m.engineering -- piping systems

HULL PIPING-ABS RULES CSN 1001/1005 KORDALIS KIRIAKOS

RULES (ABS, MACHINERY)

GENERAL PROVISIONS-DEFINITIONS

PIPES: are pressure-tight cylinders used to contain and convey fluids. The material and the dimensions should be according to the Rules or equivalent standards (ASTM, BS, JIS etc.).Pipe schedule is the designation of the pipe wall thickness according to ASTM Standards.

PIPING SYSTEM: is a network of piping and associated pumps designed to serve a specific purpose; but major equipment such as boilers, diesel engines are excluded.

PIPING COMPONENTS: are instruments connected to the pipes such as fittings, gaskets, bolts, expansion joints, filters, strainers, temperature and pressure indicators etc.

PIPE FITTINGS: are used to connect pipes such as sleeves, elbows, tees, bends, flanges etc.

VALVES: are used to control the flow of the liquid inside the pipe. Test cocks, drain valves and other similar components which perform similar function are considered as valves.

DESIGN PRESSURE: is the pressure that the system is designed (it is similar with the design pressure of the weakest component in the system). This pressure must not be less than the pressure and temperature at the most severe conditions expected during service.

FLAMMABLE FLUIDS: are considered all fluids that are liable to support a flame, regardless of the flash point. Fuel, lubricating oils, hydraulic oil (except in case that are specified as non-flammable).

TOXIC FLUIDS: are those that can cause injury, harm or death in case of shallow, inhaled or by skin contact.

CORROSIVE FLUIDS: excluding sea water are these that are able through chemical action to cause damage by coming into contact with living tissues, vessel or cargo when escaped from their containment.


CLASSES OF PIPING SYSTEMS

Pipes are divided into 3 classes according to service, pressure and temperature. Each class has specific requirements for joint design, fabrication and testing.


PIPING AND PUMP CLASS AND CERTIFICATION

FROM THE ABOVE TABLE:

ONLY CLASS I AND II PIPES REQUIRE CERTIFICATION FROM THE CLASSIFICATION SOCIETY AND ARE SUBJECT TO SHOP TEST. CLASS III PIPES DO NOT REQUIRE SHOP TEST TO BE CARRIED OUT,

ALL FITTINGS AND VALVES MUST HAVE PERMANENT IDENTIFICATION.

PUMPS THAT NEED TO BE CERTIFIED (FOR CSN 1001/1005):

1. FUEL OIL TRANSFER PUMP2. HYDRAULIC PUMPS FOR STEERING GEAR, WINDLASS3. FIRE PUMP AND EMERGENCY FIRE PUMP4. BILGE PUMP5. BALLAST PUMP6. FUEL OIL SERVICE-BOOSTER PUMPS7. SEA WATER COOLING PUMP8. FRESH WATER COOLING PUMP9. LUBRICATING PUMP

REQUIRED TEST FOR PUMP IN PRESENCE OF SURVEYOR:

1. HYDROSTATIC TEST: the pressure must be equal to 1.5P (P=maximum working pressure) and not less than 4 bars. Test can be carried out to suction side of the pump independently with 1.5Ps (maximum pressure available from the system at suction side).

2. CAPACITY TEST: that the capacity of the pump compared with the required capacity of the system at designed condition (speed and pressure head) for centrifugal pumps the characteristics curves is subject to Surveyor satisfaction).


3. RELIEF VALVE CAPACITY TEST: this test is for positive displacement pumps with an intergraded relief valve. The valve’s settings to be verified and the flow capacity.


METALLIC PIPING (MATERIALS)

Application of seamless and welded pipes

There pipes are divided into three types according the method that they are constructed:

1. Seamless, there is no welding bead on the bead2. Electric resistance welding ERW, there is a welding bead but is obvious only inside3. Welded pipes, with welding bead. This type is not used often.

Gray cast iron

Gray cast iron material should not be used in systems that are exposed to pressure shock, vibration and/or excessive strain. In general they can be used only to Class III piping systems.

Specific they cannot be used to the following:

1. Valves and fittings for temperature more than 220 C.2. Valves connected to collision bulkheads.3. Valves connected to the side shell of the vessel.4. Valves fitted outside of fuel oil, lubricant oil, cargo and hydraulic oil tanks where

are subject to static head of oil.5. Valves mounted on boilers.6. In cargo oil piping systems on weather deck for pressures exceeding 16 bars.7. Piping systems in cargo oil manifolds.8. Fixed gas extinguishing systems.

ERW, welding bead “only” inside.


Nodular (Ductile) Iron

Is not permitted for temperatures exceeding 350 C (for valves and fittings).

Nodular iron can be used for Class I, II piping systems provided it has elongation of not less 12% in 50mm (2 inches).

Carbon and carbon manganese steel

This kind of steels for pressure services are not to be used for temperatures above 400 C; unless their metallurgical behavior is specified and guaranteed from the manufactures. Consideration is to be given to the possibility of graphite formation from a specific temperature and above as below:

1. Carbon steel above 425 C.2. Carbon-molybdenum steel above 470 C.3. Chrome-molybdenum steel above 525 C with chromium less than 0.60%.

Copper and copper alloys

They can be used for Class I, II systems provided that they are of seamless type. For Class III they can be of welded type.

They should not be used for systems with temperatures as below:

1. Copper-nickel 300 C2. High temperature bronze 260 C3. All other copper and copper alloys 200 C


METALLIC PIPING (DESIGN)

Pipe wall thickness

The minimum value of the wall thickness is obtained by the ABS Rules (Part 4.6.2/5, Page 347).

Pipe branches

They can be made by the use of standard branch fittings or by welded fabrication. In the case of welded fabrication the main pipe is weakened by the hole that must be made in it to accommodate the branch pipe.

The opening is to be compensated as follow:

1. With excess wall thickness above the one specified from the requirements2. With reinforcement pads

Pipe joints

1. Butt welded joints: where complete penetration at the root is achieved and can be used for classes of piping.

2. Socket welding joints: they can be used for Class I, II for nominal diameter up to 80mm except in toxic and corrosive fluids or other services that fatigue; severe erosion is expected to occur. For class III pipes they can be used without limitation. The fillet weld leg length is to be at least 1.1 times the nominal diameter of the pipe.

3. Slip-on welded flange joints: they can be used for Class I, II for nominal diameter up to 80mm except in toxic and corrosive fluids or other services that fatigue; severe erosion is expected to occur. For class III pipes they can be used without limitation. They must provided that:

a. The inside diameter of the sleeve is not to exceed the outside diameter of the pipe by more than 2mm.

b. The depth of insertion of the pipe into the sleeve is to be at least 9.5mm.c. The gap between the two pipes to be at least 2mm


4. Flanged joints: all types of flanges must be conforming and marked in accordance with a recognized standard and they can be used for pressure and temperature rating that they are recognized. The means that flanges are attached to the pipes must be in accordance with the recognized standard that conforming to.

5. Taper thread joints: are not to be used for toxic and corrosive fluids services and for all services of temperature exceeding 495 C. they can be used for class I, II but with the following limitations and for class III without any limitation:

Flexible hoses

Flexible hose assembly is a short length of metallic or non-metallic hose normally with prefabricated end fittings ready for installation.

Flexible hoses are acceptable for fuel, lubricants, hydraulic oil, fresh water and sea water cooling systems, compressed air, bilge and ballast systems.

ARE NOT ACCEPTABLE IN HIGH PRESSURE FUEL OIL INJECTION SYSTEM.

DESIGN AND CONSTRUCTION:

Material:

1. Must be designed and constructed in accordance with a recognized standard. 2. They are incorporating a single or double closely woven integral wire braid or

other suitable material reinforcement. 3. Where rubber or plastic material hoses are to be used in oil supply for burners the

hoses are to have external wire braid protection in addition to the integral reinforcement.

4. For use in steam systems are to be of metallic construction.

Fittings:

1. Use of hose clamps is not acceptable for steam, flammable media, starting air or sea water where failure may result in flooding.


2. In other systems they may be accepted provided that the working pressure is less than 5 bar and there are at least two stainless steel clamps at each end connection.

Marking:

1. Hose manufacturer’s name or trademark2. Date of manufacture (month/year)3. Designation type reference4. Nominal diameter5. Pressure rating6. Temperature rating

Valves

All valves are to comply with national standards and permanently marked.

Design Pressure:

1. The design pressure is to be at least the maximum pressure to which they will be subjected during operation, but at least 3.5 bars.

2. For open-ended systems the design pressure can be less than 3.5 bar (including drain valves, vent valves, gauges, cocks etc.).

Construction details:

1. Handwheel: all valves must close with a right hand motion. They can be either of raising stem or fitted with an indicator to show when is closed or open.

2. Bonnet: a. Class I, II having nominal diameter exceeding 50mm are to have bolted,

pressure seal or breech lock bonnets.b. For steam and oil services are to be constructed so that the stem is

positively restrained from being screwed out of the body.c. Cast iron valves are to have bolted bonnets or are to be of the union

bonnet type, the bonnet ring is to be of steel, bronze or malleable iron.3. Valve trim: stems discs or disc faces, seats and other wear parts of valves are to

be of corrosion resistant material suitable for intended use.

Valves end:

All valves of classes I, II piping systems having nominal diameters above 50mm are to have flanged or welded ends. Welded ends are to be butt welding type except socket welding ends may be used up to 80mm.

Certificates for pressure test can be requested from the manufacturer upon request.


METALLIC PIPING (INSTALLATION DETAILS)

Protection for mechanical damage

All piping located in a position where it is liable to mechanical damage must be suitable protected. The protection arrangements are to be capable of being removed to enable inspection.

Protection of electrical equipment

The routing of pipes in the vicinity of switchboards and other electric equipment is to be avoided as far as possible. When this arrangement is necessary care is to be taken to ensure that no flanges or joints are installed over or near the equipment unless provisions are made to prevent any leakage.

Expansion joints

When expansion joints are used the following requirements apply:

1. Pipe support: adjoining pipes are to be suitably supported so that the expansion joints are not carry any significant pipe weight.

2. Alignment: expansion joints are not to be used to make up for piping misalignment errors. Misalignment reduces the expansion rates movements and can induce severe stresses into the joint material, thus causing reduced service life. Alignment is to be within manufacturer tolerance.

3. Anchoring: expansion joints are to be installed as close as possible to an anchor point.

4. Must be protected against mechanical damage.5. Must be easily accessible to permit inspection and periodic servicing.6. Rubber expansion joints with beaded end flange are not to be installed next to

wafer type check or butterfly valves.

Piping penetration through bulkheads, decks and tank top

Collision bulkheads penetration requirements:

1. Valves are to be secured directly to the collision bulkhead inside FPT. If the valves are located out of the FPT they must provide that they are secured to the after side of the collision bulkhead and are readily available at all times. They should not be located in cargo hold area.

2. The valves are to be operable from a position above the bulkhead deck and to have indicators for open/close position.

3. Grey cast iron valves are not acceptable, nodular iron is acceptable.4. No valves or cocks for sluicing (draining) purposes are to be fitted on a collision

bulkhead.


Valve in watertight bulkhead for sluicing purposes:

1. Where valves are fitted directly onto watertight bulkhead without piping on either side for sluicing, drainage or liquid transfer, the valves are to be readily accessible at all times and are to be operable from a position above the bulkhead deck. Indicators should be provided.

Protection from overpressure

A. Each piping system that may exposed to a pressure greater than the design pressure must be protected from over pressurization by a relief valve or other protecting device.

B. In case of centrifugal pump no protection is necessary because there is no possibility to exceed the design pressure.

C. For systems convey flammable liquids or gases, relief valves are to be arranged to discharge back to the suction of the pump or to a tank.

D. In case of discharge to the atmosphere the discharge is not to impinge on other piping equipment and is to be directed out from areas used by personnel.

E. Relief valves are to be set at pressure not exceed the piping design pressure.

Temperature and pressure sensing devices

A. Where such a devices are fitted in piping system, they devices should be removed without impairing the integrity of the system.

B. In case of a tank where valves are subject to static head they are to be arranged such that they may be removed without emptying the tank.

Shell connections

A. Valves must be of positive closing arrangementB. Distance piece can be usedC. Materials that in case of fire danger of flooding occur they should not be usedD. All discharges must be away from lifeboat E. Gray cast iron valves should not be usedF. The valve arrangement must be such that in case of removing the piping the water

integrity is not affectedG. Power operated valves are to be arranged for manual operation.

INSPECTION: 1. Confirm class mark, 2. Check if the supports ribs/carlings are in accordance with the approved drawing (number and position), 3. Proper operation is very important, 4. Name plates must be clean and easily readable.


PLASTIC PIPING

Where they can be used? (ABS Part 4, Page 393)


Plans and Data to be submitted:

1. Confirmation that is made in accordance with a recognized standard2. Thermal and mechanical properties3. Chemical resistance4. Spacing of supports5. Dimensions (pipes and fittings)6. Maximum internal and external working pressure7. Working temperature range8. Intended services and installation location9. Level of fire endurance10. Electric conductivity11. Fluids 12. Limits of flow rates13. Serviceable life14. Installation instructions15. Details of marking16. Supporting documents: certificates, standards, calculations, catalogues and data

sheets describing the function of each fitting.

Hydrostatic test:

The test must be carried out under the following conditions:

1. Atmospheric pressure=1 bar2. Relative humidity= 30%3. Fluid temperature 25 C

External pressure:

A pipe must be designed for an external pressure not less than the sum of pressure imposed by the maximum potential head of liquid outside of the pipe plus full vacuum inside the pipe (=1 bar). The maximum external pressure is to be determined by dividing the collapse test pressure by a safety factor of 3.

Axial strength:

Must considered thermal expansion, contraction and external loads. The allowable stress can verify experimentally or by a combination of testing and calculation methods.

Temperature:

The maximum allowable temperature to be in accordance with maker’s recommendations and in all cases must be at least 20 C below the heat distortion temperature of the pipe.

Impact resistance:After the impact test the specimen is to be subject to hydrostatic test equal to 2.5 the design pressure for at least one hour.


Installation of plastic pipes:

Supports:

1. The spacing of supports should not be less than the manufacture recommendation. Must take into account: the material, the fluid mass, thermal expansion, external forces, pressure, thrust forces, water hammer and vibrations.

2. Its support should distribute the load of the pipe over the full width of the support.3. Heavy components such as valves and expansion joints are to be independently

supported.4. Supports must allow relative movement between the hull structure and the pipes.

Shell conductivity:

The valves installed on the shell and the pipe connection to the shell are to be metallic.

HULL PIPING-SPECIFICATION CSN 1001/1005 KORDALIS KIRIAKOS

SPECIFICATION

General1. The materials and dimensions of pipes, joints, valves including bolts and nuts, etc. to

be manufactured in accordance with KS, JIS, ISO.2. The connection flanges of fuel oil manifold to be in accordance with ANSI standards.3. The material and wall thickness of pipes to meet the requirements of Classification

Society and Specification and/or changes during Plan Approval.4. All upper deck pipes should run adjacent to hatch coaming.5. Avoid arrangements which will likely cause drains to stay.6. The removal of one piping will not necessitate the disturbance of more than one pipe.7. Overboard discharges to be kept clear from accommodation ladder, embarkation

ways, load line markings and lifeboat launching.8. In way of Cargo Hold countermeasures against damage should be conducted

a. Thicker-seamless pipes to be usedb. The pitch of pipe supports to be shortenedc. The pipes to be arranged in recessed positions like inside corrugation, corner of

C/H.9. The sea valves should be fitted with short piece of heavy wall thickness. Installation

of the sea side valve to be in accordance with Rules.10. The system to be suitable arranged to allow expansion from thermal stresses and

deflections of hull structure.11. Liquid pipe lines to be kept away from electric appliances. If it is not possible welded

joint to be provided.12. No fluid pipes to penetrate the ECR.

Valves 13. In general ball valves to be provided for small bore pipes and butterfly for large bore

valves above 100mm.14. Butterfly valves to be of lug type and have nitrite butadiene rubber seat except

otherwise specified.15. Material of butterfly valves to be cast iron in general and cast steel where required

from Rules. Valve seat material to be Stainless steel, Al-Bronze for Sea water and Cast Iron for others.

16. Remote control valves to be provided with local manual operation device.17. Pressure indicators to be fitted in way of all pressure reducing valves.18. Anti-corrosion flanges to be fitted at each suction side of the S.W Pumps.

CHECK ONBOARD


Pipe joints19. The material of pipe connection to be of same material or similar to that of pipe.20. The flanges to be of steel slip on welding for steel pipes.21. Where the flange joint of larger size stainless steel pipe or non-ferrous type is

applied, the inner ring must be of same material and the outer flanges to be of hot dip galvanized mild steel.

22. Corrosion flanges should be installed for the pipes of material that are on a different level in the galvanic series.

23. Steel pipe flange for liquid handling to have seal weld at the pipe inside.24. Weather deck only steel hexagonal head bolts and nuts electroplated with zinc.25. Preformed welding socket to be used for high pressure pipes.26. Butt welding for elbow, reducer, and tee. To be penetration welding.27. Convex coupling to be used for water ballast, cable, fuel, tank cleaning, where

necessary to compensate the pipes from expansion and contraction.28. Sleeve type coupling joint with gland packing to be used for high temperature pipe

lines such as steam, hydraulic line for control valves.29. Offset expansion bends-loop may be applied to the compressed air line, steam

line in fuel tanks/heating coils and hydraulic oil lines.30. In water ballast tanks stainless steel (SUS 316) bolts and nuts to be used for flange

connections.

Branches, bends and other fittings31. Branch pipes for the low pressure piping up to 50 kg/cm2 to be welded to the main

pipe with axis angles of at least 450. For high pressure of high temperature socket type tee shall be used.

32. Branches of sanitary system to be connected to main using Y-fittings and not right angle tees.

33. Fittings forming a part of pipe to be of the equivalent material as adjoining pipes34. If the cold bending is not applicable or the radius is small, commercial elbows (bend

pieces) shall be used.35. Hot bending process may be limited adopted in special cases, like piping alignment

for adjustment.36. Fittings to be fitted by butt welding.37. Loose fittings to be selected by pipe size, pipe pressure and material according to

KS/JIS.38. Proper double plate to be fitted under all the suction bell mouth.39. Reach rod on exposed deck and in tanks to be made of stainless steel (SUS 304) and

to other places from steel round bar.

Pipe supports40. Support of non-ferrous material pipes to be inserted with similar non-ferrous material

sheet or similar hanger so as steel not to be directly contacted with the pipe.


41. Pipe supports should be attached to structural members, if possible double plate to be used.

42. Support for mainlines of 125mm and above on upper deck to be fitted with phenolic resin sliding pad to allow free sliding movement.

43. Sliding pads shall be inserted between pads and support for all ballast lines in pipe duct and ballast tanks arranged cargo hold area.

Treatment and cleaning44. The galvanizing to be carried out after fabrication. In case of welding after

galvanizing two coats of zinc coating paint shall be applied to internal and external members.

45. Pipes after pickling to be covered at ends to keep clean.46. Before connecting with the machinery flashing is required and procedure to be

submitted to Owners for approval.47. Where acid pickling is necessary after inside to be treated with oil or phosphate to

prevent rust before installation.

HULL PIPING-INSPECTION CSN 1001/1005 KORDALIS KIRIAKOS

INSPECTION OF PIPING SYSTEMS

Material confirmation and structure:a. Materials of pipes, valves and fittings should be confirmed according to drawing.b. When special materials are used such as rubber hose, plastic pipes they should be

approved by Classification Society.c. Mechanical joints should be approved also by Classification Society.d. Special attention should be paid to cast iron items such as pipes, valves and fittings

with an elongation less than 12% which they cannot be used for Class I & II except steam pipes.

Welding work for pipes and pipe fittings:a. Welders should hold welder certificate approved by Society.b. Welding procedure qualification (WPS) is required before starting welding work

and especially for special welding works such as SUS (stainless steel), aluminum etc. and for special welding procedure such as friction welding, electro beam, plasma, laser welding etc.

c. Pipes used for high temperature or/and high pressure such as main steam pipes should be inspected for grooves before welding.

d. Pre-heating should be carried out where consider necessary with oxygen-acetylene or propane gas to the proper extend about 300-350mm from the welding line.

e. Post welds heat treatment and non destructive tests.f. Inspection of welding normally is carried out during hydraulic test in manufacture

promises, the following items should be checked: 1. Overlap and undercut shall not exist.2. No pits on bead.3. Fillet beads size according to Rules.4. Proper height of welds.5. Penetration must be good.6. Slag must be completely removed.7. No deformation on flanges caused by welding may exist.8. Welding condition at butt joints and branches must be good.

Hydraulic test:a. No fragile materials to be used for gaskets.b. Standards of flange must be correct.c. Pipes required to be annealed should be annealed before test.d. No leak must be found.e. Seal welding on inner surface of flange must be carried out.f. Welding parts and penetrating parts on pipe inside must be finished with grinders.g. In case of backing plate for welding no defect may be found on the inner side.h. Bending radius of pipes must be at least 2-3 times the outside diameter except

otherwise specified by Society.i. No trouble must be found in wrinkle condition by bending.j. No defective part such as seizing sand may be found on pipe inner surface.k. No defects such as hammer traces, cramp traces may be found on the outside

surface of pipes.


General inspection items:b. All items such as pipes, valves, fittings, cocks, rods, handles of valves etc. should

be surely fitted.c. If they are fitted to place where damage can easily occur they must protected by

covers that they can easily removed.d. A proper clearance approximately 20mm should be provided around each pipe

and between pipe and pipe or hull structuree. Piping should be arranged so that neither drain on air can stay insidef. Air relieving systems or drainage systems should be provided whether air or drain

can accumulateg. Opening position of relieving valves or drain valves should be arranged in a

position that cannot sustain damage to the crew or to other equipment.h. Removal joints should be arranged to an easily accessed place so maintenance

and removal can easily carried out.i. Consideration should be given to pipe expansion, contraction and hull

deformation.j. Valves should be arranged where they can easily operated, stands or reach rods

can provided.k. Uneven fastenings should be avoided.l. Pipe supports should not fix parts which expand, contract or move.m. When large pipes are support alongside shell or tank wall, pipe support should be

fitted to locations which the back sides are reinforced.n. Oil fuel lines are not to be fitted close to high temperature units.o. Joints of heating pipes are recommended to have butt welded joints instead of

flange joints.p. When drain pipes are used in engine room area proper non-return devices should

be arranged.q. Stop valves should be provided on suction pipes of the APT at the forward

bulkhead.r. Slip joints should not be used for pipes inside cargo holds, deep tanks and other

compartments difficult to access. The joints of bilge pipes and ballast pipes in these compartments should be provided with flange joint or welded joints.

s. Pipes supports are not to be unreasonable fastened in order to avoid badly affect on pipe or equipment.

t. In the case that pipes are going through watertight compartments suitable measures should be provided.

u. Spindles of various valves shall not go through this sections which sustain liquid head pressure such as inner bottom plates. When it is unavoidably for pipes to pass through these compartments special consideration should be given. For instance, protecting pipes should be arranged to stuffing boxes of spindles to avoid liquid head pressure.


Other items for consideration/design:a. Piping should not be located near to electric equipment and if this is unavoidable

joints construction shall be considered to prevent leakage. Usually butt joints are preferable.

b. Non interference between boiler feed water piping/tank system and oil system shall exist.

c. The gaskets that are used for the piping system should be in accordance with recognized standard and their selection should be made after consideration of the working environment (temperature, pressure etc.)

d. When non-asbestos gaskets are being used, it should be confirmed that works are carried out according to maker recommendations (kind of packing, fastening torques etc.)

e. PVC and GRP pipes can be used for piping except for importance uses.f. There is a limitation regarding the usage of rubber sheet butterfly valves,

especially for temperatures above 70 degrees or/and pressure above 1.6 Mpa the valve must be of an approved type. Exceptions are the EPMD type valves that are used for the Sea water or Fresh water system.

g. Surfaces with temperature above 220 degrees must be properly insulated.

Pump installation inspection (Newbuildings)

In order to prevent vibration and noise and long life operation of the pump and safeguard the best efficiency and safety, it is necessary to pay special attention to the alignment of the pump with its driver.

The maximum allowable offsets are:

1. Between the driver and intermediate shaft:a. Parallel misalignment at coupling <0.2 mmb. Angular misalignment at coupling <0.2 mm

2. Between intermediate shaft and pumpa. Parallel misalignment at coupling <0.4 mmb. Angular misalignment at coupling <0.2 mm

During the installation of the pump, place, foundation and the finishing of the pump at mounting seats are to be carefully considered to obtain a proper alignment.

Excessive vibration is also unacceptable and the following issues should be considered:

1. Piping should present any deformation and parallel/angular misalignment.2. Suction pipes should exempt of air pocket, to prevent leakage and should be

clean and perfectly tightened.3. The permissible deformations are as below:

a. Vertical deviation +/- 10mmb. Angle <50

c. Perpendicular deviation +/-8mm

HULL PIPING-PUMPS KORDALIS KIRIAKOS

PUMPS There are in the market various types of pumps with different characteristics and for different usage depending from the working conditions. Usually the most common pumps for use on board are positive displacement type and centrifugal (dynamic pressure pumps). Their main characteristic of the positive displacement is that they discharge a known quantity of liquid with each revolution of the main element. The pump discharge liquid by creating a space between the pumping element and the case. Rotary pumps are self-priming and deliver a smooth flow regardless of pressure variations. Dynamic pressure pumps, a tangential acceleration are imparted to the fluid centrifugal, axial and mixed flow pumps). Depending to supply head they may require a priming device (vacuum mechanism or a displacement pump); they are used general for medium and high discharge rates and for low viscosity liquids.

For liquids and piping systems with different conditions different type of pumps is used:i. For cooling/ballast water system-centrifugal pressure low pressure/high capacityii. Lubricant oil-screw type, constant supply and pressureiii. Boiler feed water-2 or 3 stage centrifugal pumps or piston pumpsiv. Fire pumps-high pressure centrifugal pumpsv. High viscosity fuels-gear type pumpsvi. Dirty water-piston pumps, reciprocating type

The selection of the type of the pump is not always an easy decision and the parameters that they have to be considered are many. The first consideration is the pumping conditions the amount of liquid that has to transferred, the temperature, the type of the liquid, the viscosity, the suction/discharge head.

INSTALLATION, OPERATION AND MAINTENANCE

Preparation for shipment:

After a pump is assembled at manufacturer shop it should be suitably prepared for shipment. There are some cases that the rotor must be blocked and this can be identified by weather resistant tags. The preparation must withstand at least 6 months outdoor storage. The pump and the driver should be prepared for shipment only after all testing’s and inspections have been completed.

The pump must be completed dried and drained before the shipment and all the internal parts should be coated with a suitable rust preventative within four hours from the testing. Alternatively within four hours from the testing the pump and the seal chamber should be drained to the extend practical, filled with a water displacing inhibitor and re-drained for shipment.

Flanged openings should be provided with covers at least 5mm thick and sealed with an elastomeric gasket.

Threaded openings should provided with caps or plugs and all openings that have been prepared for welding in the field should be provided with closures devices and must be surely secured so foreign materials don’t get in the equipment.


Exposed shafts or rotors should be wrapped with waterproof cloth or paper and sealed with oil-proof tape.

Bearings must be protected from moisture and dust. If vapor phase inhibitor in bags used, their location must be marked so they will be removed before installation.

Care of equipment in the field:

All equipment should be stored free from ground contact. Away from areas that there is a possibility to collect water. Indoor storage should be used wherever is possible. Especially carbon and alloys should be protected from corrosive environments

(machined surfaces also) in order to prevent rust formation. Periodic rotation of shafts should be carried out (first check that there is adequate

lubricity). Preservatives and storage lubricants can affect safety and operating life especially if

they will react with the process fluid and operating lubricant.

Pump location:

Working space must be considered, suitable for maintenance and lifting operations. Axial split casing pumps require sufficient headroom to lift the upper half of the

casing. For large parts the location must be within the limits of the crane arrangement. Pumps generally should be located as close as practicable to the source of liquid

supply.

Foundations:

May consist of every structure heavy enough to afford permanent rigid support and to absorb any shocks.

The most satisfactory are concrete foundations built up from solid ground. Mis-alignment is corrected with shims. Each foundation bolt should be surrounded by a pipe sleeve three or four diameters

larger than the diameter of the bolt. Then unit should be arranged as close as possible to main strength members and

special care should be given that the base plate cannot be distorted and affect the alignment.

Alignment:

When a complete unit is assembled at the factory, the baseplate is installed on a flat-even surface. The pump is usually doweled on the baseplate at the factory and the driver is left to be doweled after installation on site.

The coupling halves are also aligned at the factory and can aligned during installation by adding shims under the mounting surface of the driver.

Space around 2-5mm must be allowed between the bottom of the baseplate and the top of the foundation for grouting.

Coupling bolts should be removed before the unit is leveled and the coupling halves are aligned.

The steel supporting strips or shims under the baseplate should be adjusted until the pump shaft is aligned. The nuts on the foundation bolts should be made handtight.


The alignment should be checked with filler gauges. For all alignment checks both shafts should be pressed hard to one side when taking the readings.

When the peripheries of the coupling are true circles with equal diameter and the faces are flat and perpendicular to the shaft axis, exact alignment exists when the distance between the faces is everywhere equal.

In some cases for accuracy reason the diameters maybe different or then shape different than a true circle. To check the alignment in this case you can hold one shaft stationary and rotate the other one. The alignment shall be checked to each quarter turn.

A more exact method for measuring the alignment is with a dial gauge, the method called face and rim alignment because both radial and axis alignment can be measured. The button of the indicator should be rest to one coupling, the dial should be set to zero and a chalk mark needs to indicate the point that the indicator touch the surface. For any check the shafts must be rotated with the same amount and the indicator should remain on chalk mark. After any movement of the shaft the coupling surface must be checked that remain parallel.

Allowances are necessary for pump that they will handle liquids at high temperature because of the thermal expansion.

When the unit has been aligned the hold down bolts should be gently and evenly tightened before grouting.

The alignment must be rechecked after suction and discharged piping have been bolted.

Grouting:

Baseplate is grounded before the piping connection is made and before the final alignment of the coupling halves is rechecked.

Purpose of grouting is: to prevent lateral shifting, to increase the mass, to reduce the vibration and to fill irregularities in foundation.

The pump must be removable without disturbing the grout. There are two types of grouts; these are epoxy type and cement-base type. The epoxy

type has significant advantages as higher strength and non-porous surface but is more expensive. Generally is used for pumps installation.

A preliminary alignment check is carried out before the grouting in order to ensure that the final alignment is possible after the baseplate is finally grouted.

Grout and air holes allow air to escape as the grout fills the cavity. The foundation/holding down bolts can be finally torque after the grout has cured and

the coupling halves can be rechecked for alignment. The grout must be hardened permanently.

HULL PIPING-CENTRIFUGAL PUMPS KORDALIS KIRIAKOS

CENTRIFUGAL PUMPS (Rotor dynamic/pressure pump)An introduction to Centrifugal Pumps

A centrifugal pump converts the input power to kinetic energy in the liquid by accelerating the liquid by a revolving device - an impeller. The most common type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radically outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump.

The energy created by the pump is kinetic energy according the Bernoulli Equation. The energy transferred to the liquid corresponds to the velocity at the edge or vane tip of the impeller. The faster the impeller revolves or the bigger the impeller is the higher will the velocity of the liquid energy transferred to the liquid be. This is described by the Affinity Laws.

Pressure and Head

If the discharge of a centrifugal pump is pointed straight up into the air the fluid will pumped to a certain height - or head - called the shut off head. This maximum head is mainly determined by the outside diameter of the pump's impeller and the speed of the rotating shaft. The head will change as the capacity of the pump is altered.

The kinetic energy of a liquid coming out of an impeller is obstructed by creating a resistance in the flow. The first resistance is created by the pump casing which catches the liquid and slows it down. When the liquid slows down the kinetic energy is converted to pressure energy.

It is the resistance to the pump's flow that is read on a pressure gauge attached to the discharge line. A pump does not create pressure, it only creates flow. Pressure is a measurement of the resistance to flow.

In Newtonian fluids (non-viscous liquids like water or gasoline) the term head is used to measure the kinetic energy which a pump creates. Head is a measurement of the height of the liquid column the pump creates from the kinetic energy the pump gives to the liquid. The main reason for using head instead of pressure to measure centrifugal pumps energy is that the pressure from a pump will change if the specific gravity (weight) of the liquid changes, but the head will not. The pump's performance on any Newtonian fluid can always be described by using the term head.

Different Types of Pump Head

•Total Static Head - Total head when the pump is not running

•Total Dynamic Head (Total System Head) - Total head when the pump is running

•Static Suction Head - Head on the suction side, with pump off, if the head is higher than the pump impeller

•Static Suction Lift - Head on the suction side, with pump off, if the head is lower than the pump impeller

•Static Discharge Head - Head on discharge side of pump with the pump off

•Dynamic Suction Head/Lift - Head on suction side of pump with pump on

HULL PIPING-CENTRIFUGAL PUMPS KORDALIS KIRIAKOS

•Dynamic Discharge Head - Head on discharge side of pump with pump on

The head is measured in either feet or meters and can be converted to common units for pressure as psi or bar.

It is important to understand that the pump will pump all fluids to the same height if the shaft is turning at the same rpm. The only difference between the fluids is the amount of power it takes to get the shaft to the proper rpm. The higher the specific gravity of the fluid the more power is required.

•Centrifugal Pumps are "constant head machines"

Note that the latter is not a constant pressure machine, since pressure is a function of head and density. The head is constant, even if the density (and therefore pressure) changes.

Converting head in meter to pressure in bar

Pump curves in meter of head can be converted to pressure - bar - by the expression:

p = 0.0981 h SG

Where h= head (m), p= pressure (bar), SG=Specific Gravity

Centrifugal pump characteristics selection:

1. Depends mainly upon duty and space available.

2. Flow and total head requirements.

3. Speed of rotation, impeller dimensions, number of impellers.

4. Range of temperature of fluid to be pumped.

5. Viscosity of liquid to be pumped.

6. Type of liquid, corrosive or non-corrosive, this would affect the choice of material and the difference is mainly to main casing material.

7. Materials could be used are: casing-gunmetal-cast iron for fresh water, impeller-aluminum-bronze, shaft-stainless steel, casing bearings-bronze.

Vertically arranged pumps require less floor space and no hydraulic balance is necessary further impeller access is simple and no pipe joints need to be broken.

HULL PIPING-AXIAL AND MIXED FLOW PUMPS

KORDALIS KIRIAKOS

AXIAL AND MIXED FLOW PUMP (Rotor dynamic/pressure pump)

When large capacity and wide variation of low lift head at a constant speed have to be met, the horizontal or vertically arranged axial pump is more suitable. It can be also operate in reversible mode (a friction clutch is required between motor and pump) and is ideally suited to scoop intake condensers as it offers very small resistance when idling.

The casing is usually made of cast iron or gun metal and the impeller made of aluminum or bronze. The pump shaft is made of stainless steel with solid and flexible couplings.

A water cooled thrust is required because of the thrust that generated.

Due to the casing shape the water is made to flow from and towards the rotor centre during each revolution. The water motion is utilised to act as suction and discharge for the air through appropriate sets of ports. The rotor casing is continuously cooled by a closed water circuit from the pump discharge round the air pump jacket and returns to the pump suction. The air pump can be placed in or out of operation by a control cock on the front of the air pump casing. The principle of operations is referred to as the 'water ring principle'. The figure shows this in simplified form. As the impeller vanes pass the suction port air is drawn in and trapped between the water ring and the pump shaft. This 'slug' of air is carried around and delivered to the discharge port, hence this pump is a positive displacement type. In some ship plants all the priming connections for all pumps, etc, are let to a central exhausting system, this system under the operation of auto compressors functions to give priming from a central control station to all units in the engine room as required.

A screw propeller is used to accelerate the liquid. The outlet passages and guide vanes are arranged to convert the velocity increase of the liquid into a pressure. The type of pump shown opposite is of reversible type. The casing is of split type to provide access in case of maintenance. In the area that the shaft leaves the casing a mechanical seal is provided to prevent leakage.

A thrust bearing of the tilting pad is fitted on the drive shaft and it may need cooling system.

Suitable for: large capacity of liquid in low head.

The advantage in comparison with a centrifugal pump is the use of a smaller driving motor with higher speed.

In case of scoop of a condenser system the pump can be used when the speed of the vessel is small or the vessel has stopped.

HULL PIPING- POSITIVE DISPLACEMENT PUMPS

KORDALIS KIRIAKOS

POSITIVE DISPLACEMENT PUMPS (GENERAL)

The displacement pumping action is achieved by the reduction/increase in volume of a space causing the trapped liquid to be physically moved. The method employed with:

1. Piston in a cylinder using a reciprocating motion2. Rotating units such as:

i. Vanesii. Gearsiii. Screws

The pumping conditions must be evaluated before the type of pump that will be used. Positive displacement pumps are used in case of; requirement of standard amount of floe regardless the differential pressure; high viscosity; need for high differential pressure. But they can be usually used for small to medium discharge rates. They are used and as priming devices for other pumps with high flow rate.

Inlet conditions: flow rate; differential pressure; temperature; particle size; liquid characteristics.

A pump needs proper suction conditions to work well. PD pumps are self-priming, and it is often assumed that suction conditions are not important. But they are. Each PD pump has a minimum inlet pressure requirement to fill individual pump cavities. If these cavities are not completely filled, total pump flow is diminished. Pump manufacturers supply information on minimum inlet conditions required. If high lift or high vacuum inlet conditions exist, special attention must be paid to the suction side of the pump.

HULL PIPING-RECIPROCATING PD PUMPS KORDALIS KIRIAKOS

RECIPROCATING PD

Is self priming pump and has extremely flexibility in operation, from no load to full load and can handle with manual and automatic control.

The pump is double-acting, the liquid is admitted from the one side of the piston and it is discharged from the other side.

There are two types:

1. Simplex type that has the disadvantage that the flow is not steady and there is a series of flu actions. This can result in vibrations and heavy shock loadings with possible damage to the pump and to piping system if there is no arrangement to accommodate the pulsation. This type of pump is normally fitted with air-vessel that absorbs the flu actions in discharge pressure.

2. Duplex type that has the advantage against of the Simplex type that produce a continuous uniform flow. This is particularly important is such systems as boiler feed water. There are two pistons and when the first one has reached the end of its stroke the other is still moving and so maintaining a smooth flow without flu actions. No dead centre exists as one of the seam ports is always open and the pump will start immediately because steam is admitted to the cylinder.


Reciprocating Piston Pumps

The basic principle of the reciprocating single piston pump is shown below. The piston expels liquid through a one-way valve (check valve). The pumping rate is usually adjusted by controlling the distance the piston retracts, thus limiting the amount of liquid pushed out by each stroke, or by the cam rotating speed.

Schematic of the reciprocating single piston pump. CAM is pushing a sapphire piston back and force. When the piston is moving backwards it sucks the eluent through the inlet check valve (on the bottom). The sapphire ball is lifted and opens the path for the eluent. When the piston moves forward, the liquid pushes the inlet ball down and closes the path, but the outlet ball is lifted and opens the outlet valve (upper).

The main disadvantage of this type of pump is sinusoidal pressure pulsations which lead to the necessity of using pulse dampers.

Dual Piston Pumps

A more efficient way to provide a constant and almost pulse free flow is the use of dual-headed reciprocating pumps. Both pump chambers are driven by the same motor through a common eccentric cam; this common drive allows one piston to pump while the other is refilling. As a result, the two flow-profiles overlap each other significantly reducing the pulsation downstream of the pump; this is visualized below. Since the acceleration/deceleration profile is somewhat non-linear, the more efficient types of these pumps use eccentricity-shaped cams to obtain the best overlapping of the pressure curves and to obtain smooth flow.

http://hplc.chem.shu.edu/NEW/HPLC_Book/Instrumentation/pmp_damp.html


Schematic of a dual-head reciprocating pumps.

The advantages of this pump are the unlimited solvent reservoir allowing long-term unattended use and quick changeover and clean out capability. However, unless special care has been exercised in manufacture, these pumps may have several disadvantages. There is a tendency for the incompletely compensated pulsations to be observable at high refractive index detector sensitivities, especially at low flow rates where piston cycles are widely spread. Furthermore, since each head has two check valves, pump reliability depends on the cleanliness of the mobile phase and continued sealing capability of four check valves on each cycle, with cycles normally occurring several times per minute.

Recent improvements to this popular pumping system include:

A computer-designed camshaft is used to achieve maximum overlap of pump strokes, resulting in virtually undetectable pulsation or ripple.

Staggered inlet/outlet lines are employed to allow complete flushing when liquids are changed or if air is inadvertently drawn through the pump.

Small-volume check valves are used to allow the pumps to function reliably at flow rates as low as 0.001 mL/min. This has the added benefit of providing excellent gradient reproducibility especially when programs start from extremely low concentrations.

There are fewer moving parts, with all maintenance-requiring components (pump seals, check valves) readily accessible from the front of the instrument.

A wide flow rate range (0.01 to 10 ml/min) is provided without gear change.

Check valves on the reciprocating pump are the weakest part. It may be easily contaminated or clogged which leads to the pump malfunction. Most of the recent HPLC instruments use improved dual piston pumps which have three or even two check valves.

http://hplc.chem.shu.edu/NEW/HPLC_Book/Detectors/det_ri.html


The schematic of this pump is shown above. The first piston, called low pressure, is sucks the liquid from the reservoir while the second (high pressure piston) is supplying the fluent to the system. Then the first piston refills the second piston very fast, during 1/100 of the whole pump cycle. This scheme allows the use of only 3 check valve, one of which is working under low pressure. There are no cavitations effects. Because the piston volumes are small, pressure pulsations are small and sharp and easy to damp.

Another type of dual piston pump uses only two check valves, but piston volumes are different.

While the smaller piston dispenses an fluent in the HPLC system, the bigger piston is sucking an fluent. When pistons change their direction, the bigger piston simultaneously refills the smaller chamber and dispenses fluent into the system.

This set-up allows only two check valves for the dual piston pump.

Pressure Dampers

It is obvious that these pumps deliver a series of "pulses" of the mobile phase. Most detectors, but in particular the refractive index detector, are sensitive to flow "pulses" and for both trace analysis or good quantitation, it may be necessary to eliminate the pulsations. Several methods have been developed to accomplish this. The most simple involves placing a large coil of narrow-bore tubing in the line between the pump and the injector.

As the pump strokes, the coil flexes, absorbing the energy of the pulsations. This type of pulse damper holds a large amount of liquid which must be purged during solvent changes or when performing gradient elution. Another variation of this is a pressure gauge with a large Bourdon tube (usually of the follow-through type, to prevent trapping of liquid) which also flexes with each pulse. The most usual damper type is a membrane one, usually having low volume (less than 0.5 ml). The left part is filled with inert liquid . Compressibility of this liquid is enough to compensate for the pulsations of the dual piston pump with piston volume around.

http://hplc.chem.shu.edu/NEW/HPLC_Book/Instrumentation/pmp_recp.html#DUAL%20PISTON%20PUMPS

http://hplc.chem.shu.edu/NEW/HPLC_Book/Instrumentation/pmp_recp.html#DUAL%20PISTON%20PUMPS

http://hplc.chem.shu.edu/NEW/HPLC_Book/Detectors/det_ri.html


Flow and pressure profiles for different types of pumps and cam shape.

The piston movement profile which is used for new pumps is shown above. First stage (1) has a sharp slope to compensate liquid compressibility. The second stage (2) is the solvent delivering step and it is the largest in the pumping cycle, the third stage (3) is the filling procedure; this stage is about 1/50 of total cycle time. This type of cycle is controlled by a microprocessor and driven by a stepping motor. Pulsation profile produced by this pump is shown above. A small volume diaphragm damper combined with electronic pressure gauge is more than enough to compensate for short term pressure peaks.


SCREW TYPE:

Considering the figure it is seen that the fluids enters the outer suction manifolds and passes through the meshing worm wheels which are gear driven from a motor to the central discharge manifold. Such pumps are quiet and reliable and are suited to pumping all the fluids. The pump can deal with large volumes of air whilst running smoothly and maintaining discharge pressure. Some pumps are fitted with timing gears to ensure that correct clearance is maintained at all times between the screws thus preventing overheating and possible seizure.


Screw pumps are rotary, positive displacement pumps that can have one or more screws to transfer high or low viscosity fluids along an axis. A classic example of screw pumps is the Archimedes screw pump that is still used in irrigation and agricultural applications.

Although progressive cavity pumps can be referred to as a single screw pumps, typically screw pumps have two or more intermeshing screws rotating axially clockwise or counterclockwise. Each screw thread is matched to carry a specific volume of fluid. Like gear pumps, screw pumps may include a stationary screw with a rotating screw or screws. Fluid is transferred through successive contact between the housing and the screw flights from one thread to the next. Geometries can vary. Screw pumps provide a specific volume with each cycle and can be dependable in metering applications.

The geometries of the single or multiple screws and the drive speed will affect the pumping action required. The capacity of screw pumps can be calculated based on the dimensions of the pump, the dimensions of the surface of the screws, and the rotational speed of the rotor since a specific volume is transferred with each revolution. In applications where multiple rotors are used, the load is divided between a numbers of rotating screws. The casing acts as the stator when two or more rotors are used. Based upon the needs of the application, timed or untimed rotors may be chosen. Untimed rotors are simpler in design.

The combination of factors relating to the drive speed, flow, and the characteristics of the fluid transferred may affect the flow rate and volume fed through each cavity. In water and wastewater treatment applications, a less viscous solution will require a lower power drive compared to untreated sewage, excess sludge, or concentrated slurries, which may require a higher power motor. The viscosity of the fluid transferred and the lift required may affect the speed and power required. Indicators of pump malfunction include decrease in flow rate or increased noise. The efficiency of screw pumps requires that each rotor turns at a rate that allows each cavity to fill completely in order to work at full capacity.

http://www.globalspec.com/datasheets/1916/areaspec/media_waste_water

http://www.globalspec.com/datasheets/1916/areaspec/power_water

HULL PIPING-VALVES KORDALIS KIRIAKOS

VALVES

Many types of valves are used to control the flow of the fluid. The valves that are used in shipping industry can categorize to following groups:

1. Stop valves

2. Check valves

Beside the basic types of valves there are some special valves that they cannot categorize to above mentioned groups. Some of these are the pressure control valves, thermostatic recirculating valves and many others.

Basic valves figures:

1. STOP VALVES

Are used to shut off (partially or totally) the flow of the fluid. The valves are controlled by the movement of the valve stem. Stop valves can be divided into four categories:

c. Globe valvesd. Gate valvese. Butterfly valvesf. Ball valves

GLOBE VALVES


Are probably the most common valves in use. The name derives from the globular shape of the valve body (this is not exhaustive because it is possible and other types of valves to have globular body shape).

Globe valves are consisting of a movable disk element, a stationary ring seat and generally a spherical body. The body inside is separated by an internal baffle. This has an opening that forms the seat onto which a movable plug can be screwed. The plug is also called disk.

The plug is connected with a stem which is operated by screw action for manual valves. The stem is operated by a hand wheel.

Globe valves are used for applications requiring throttling (control the flow amount of the liquid) and frequent operation. Because of the internal baffle there is a considerably increase of the fluid resistance so they are not recommended for systems that unobstructed floe is required.

Bonnet: provides a leak proof closure for the valve, it can be screw-in, bolted or union, it contains also the packing material that provide the seal between the bonnet and the stem during operation. The packing is wearable material and has to be replaced during overhauling.

Plug or Disc: is the closure member of the valve and are connected to the stem which is slid or screwed in order to throttle the flow. There are two types of plugs, unbalanced and balanced. The unbalanced are solid and they are used for small valves (for big valves the forces that are required to control the flow are impracticable) and low pressure systems, the design is simpler and lower cost is involved. Balance plugs have holes through the plug, the advantage is easier shut off as the plug has no static forces to overcome, the disadvantage is that a second leak path is created and the cost involved is generally higher.

Stem: serves to transmission of the movement from the wheel to the valve. Stem can be treated if serves manual operation or smooth for actuator controlled valves. With a smooth stem the ends are treated to allow connection to the plug and to the actuator. The stam must be straight in order to ensure proper closure of the valve and to minimize the packing material wear. A shroud can be provided to prevent foreign materials entering the body.


Cage: The cage is part of the valve that surrounds the plug and is located inside the body of the valve. Typically, the cage is one of the greatest determiners of flow within the valve. As the plug is moved more of the openings in the cage are exposed and flow is increased and vise versa. The design and layout of the openings can have a large effect on flow of material (the flow characteristics of different materials at temperatures, pressures that are in a range). Cages are also used to guide the plug to the seat of the valve for a good shutoff, substituting the guiding from the bonnet.

Seat Ring: The seat ring provides a stable, uniform and replaceable shut off surface. Seat rings are usually held in place by pressure from the fastening of the bonnet to the top of the body. This pushes the cage down on the lip of the seat ring and holds it firmly to the body of the valve. Seat rings may also be threaded and screwed into a thread cut in the same area of the body. However this method makes removal of the seat ring during maintenance difficult if not impossible. Seat rings are also typically bevelled at the seating surface to allow for some guiding during the final stages of closing the valve.

GATE VALVES (SLUICE)

Gate valves are used when a straight line flow and minimum restriction is desired. It acts like opening and closing a gate and so as this name. When the valve is open the gate is drawn up into the valve. The pressure drop through the valve exists but is very small in conjunction with other type of valves.

The Gate valves are not suitable for throttling purpose and serious damage to the gate occurs.

http://en.wikipedia.org/wiki/Temperatures


There are two types of gate valves;

1. The first one is with rising stem (as first figure below) where the stem is attached to the gate and so gate and stem moving up and down together as the valve operates. Rising stems are provided with a visual indicator.

2. The second is with non-rising stem where the stem is threaded to the lower part and into the gate. As the hand wheel on stem is rotated the gate moving on the stem threads and the stem remain to the same vertical position. This type is used when the vertical space is limited.

They used mainly to steam systems and they use flexible gates in order to prevent binding of the gate inside the gate when the valve is in close position. The reason is that steam systems have high temperatures and the lines will expand; causing distortion to valve bodies.

The gate face can form a wedge shape or to be planar. Usually they are provided with bonnet for leak proof; screw in bonnet is the simplest and offer a pressure tight seal; union bonnet is suitable for applications requiring frequent inspection and maintenance; and bolted bonnet is used for large valves and high pressure operations.

If the pressure exceed 15 Mpa (150 kg/cm2), pressure seal bonnet is normally used. In this kind of bonnet the joint-seal between the valve body and the bonnet is increased as the pressure increased. In other types when the internal pressure increases the joint tends to leak. The material that they are constructed can be cast iron, cast steel, stainless steel, alloy steels and forged steels.

BUTTERFLY VALVES

They used in variety systems on a vessel. The advantages of this kind of valve are that they are:

1. Light in a weight2. Relatively small3. Quick acting4. Provide positive shut off


5. Suitable for throttling

The elements of a butterfly valve are: body; resilient seat; stem; packing; positioning plate and a handle.

It is important, the resilient seat to be under compression during the installation, thus making a seal around the disk and the upper and lower points where stem is passing through. Packing is provided to form a positive seal around the stem for protection in case that the seal deformed by the seat. Some large valves or in case that there is not enough space for a wheel with a large diameter the valve can be operated through a gearing arrangement.

Butterfly valves are ease to maintenance and the seal held in place by mechanical means and either bonding or cement is necessary. The seat is replaceable so there is no need for lapping, grinding or machine work.

BALL VALVES

Ball valves as their name they are using a ball to stop the flow of the fluid. The action of the ball is the same like the disk in the globe valve. When the valve is open the hole is in-line with flow and when it is closed 90 degrees angle is required and the hole is perpendicular to the flow.


Most of the ball valves are of quick acting type because requiring only 90 degrees turn to operate the valve. Also there are some other types that they use a gear for the operation, the benefit is small diameter hand-wheels can be used for large valves but the requiring angle for operation is bigger and is depend from type of the gear.

Some ball valves contain a swing check valve inside the ball and they have a check valve feature. Ball valves are durable and they can achieve a perfect shut off of the flow even after many years of operation. They are not suitable for throttling purposes although they can be used for this in some conditions.

They are used extensively to industry because they are very versatile and they can operate safely under high pressures and temperatures. There are also 3-way ball valves with L or T shape and they can control the flow with different combinations. Multi port ball valves are also available with 4 or more ways. These are used to special applications such as driving air powered motors from forward to reverse.

There are single, two and three pieces design. One piece are generally throw-away because they cannot repaired, two pieces design can be throw-away or repair. The 3-piece design allows for a better maintenance and the elements can easily removed from the pipeline with result that deposits can be cleaned, replacement of packing gland-seat is easy and small scratches on ball body can be repaired.

CHECK VALVESCheck valves are used to allow flow direction in only one direction. They are operated by the flow of fluid in the piping. A check valve may be of swing type, lift type or ball type.

Some valves however function either as stop valve or as check valves depending on the position of the valve steam. These valves are known as stop-check valves. This type of valve is shown in figure below and it looks very much like a lift check valve. The stem in these valves is long enough so when it is screwed all the way down it holds the disc


firmly against the seat; thus preventing any flow of fluid. In this position the valve acts as a stop valve. When the stem is raised, the disc valves acts as a check valve allowing the flow of the liquid in only one direction.

The maximum lift of the disk can be controlled by the position of the valve stem. So the amount of the fluid passing through can be easily controlled and when the valve is operate as check valve. They are used on many drain lines and on the discharge of many pumps to prevent backflow.

HULL PIPING-BALLAST SYSTEM KORDALIS KIRIAKOS

HULL PIPING SYSTEMS

BALLAST WATER SYSTEM

SPECIFICATION

1. Shifting of water between port and starboard side should be considered. 2. Line for APT shall be independent and to be led through the engine room. 3. No ballast through fuel tanks. 4. A stripping system shall be led directly from main line to each DB tank with

individual valves. The valves shall be located inside lower stools for easy maintenance.

5. The eductor for stripping is to be driven from Bilge and Fire-General service pumps.6. Two (2) ballast eductors.7. Doubling plates to be provided under bell mouths inside ballast tanks.8. 300mm diameter pipe to be provided in Cargo hold No. 3 on both port and starboard

side at the aft end. The pipe shall be installed in lower stool of the cargo hold. 9. Each valve to be equipped with manual Hydraulic operated.

10. All valves to be remote hydraulically controlled. 11. Connection pipe from Fire line on deck to be provided for topping up the Cargo hold

No.3. 12. The ballast main line to be also connected to Fire & Bilge pump.

ABS Rules (Machinery Part 4, Chapter 6, Section 4)

1. At least two power driven ballast pumps are to be provided2. Pumps must be certified according to Rules (Hydro, Capacity, Relief valve test)3. Ballast valves must be arranged to controlling the flow to the ballast tanks and they

must remain closed at all times except ballasting. Where butterfly valves are used they are to be of positive holding arrangement, or equivalent, that will prevent movement of the valve position due to vibration or flow of fluids.

4. Remote control valves are to be arranged so that they will remain closed in the event of loss of control power, alternatively they can remain in the last ordered position provided that there is an accessible manual mean for operate the valve upon loss of power.

5. Remote control valves are to be clearly identified as to the tanks they serve and are to be provided with position indicators at the ballast control station.

RUNNING AND MAINTENANCE (IMAREST)

When a vessel must proceed between two ports without cargo or partially loaded, it may be necessary to take ballast on it for many reasons or combination of them:

1. To increase the draft and give sufficient immersion of the propeller.2. To give better rudder reaction due to the greater depth of water flow.3. To provide satisfactory stability conditions.4. To assist in better weight distribution, thus reducing hull stresses.5. To give to the ship better see-keeping abilities in heavy weather.

There are some loading conditions that the vessel’s stability tends to decrease due to fuel oil consumption from double bottom tanks, in this condition the ship may be flop

BA 23


from side to side and possible to become dangerous. In this case the double bottom tanks must be filled in order to obtain the desired degree of stability.

The order in which either port or starboard tanks are filled is of great importance.

The double bottom tanks are not filled haphazardly but only after all the facts have been studied and instructions are passed on by the chief engineer.

If a cargo ship is fitted with heavy lift cargo gear, a part of ballast system must be designed to accommodate the rapid changes of heel and stability which occur during heavy lift operations. The port and starboard ballast tanks must be capable of being filled very rapidly, emptied or transferred from port to starboard and vice versa. A deep tank usually is fitted in front of engine room for this purpose and is divided into center and port, starboard wings tanks which they are giving the maximum amount of leverage.

Ballast pumps capacities are positioned by the minimum time requirement for filling or discharging ballast prior to, during or after cargo operations. BALLASTING AND DE-BALLASTING OPERATIONS: there is no set of specific rules for these operations. The certain conditions of the vessel must be evaluated before start an operation. The conditions that must be observed related with the stability, pollution, reducing hull stresses and to avoid hull damage due to tank pressurization.Before the tanks are filled or emptied the closing devices or covers to air pipes must be removed so that the air can easily enter or leave from the tank. Failure or ignorance to remove the closing devices has sometimes resulted in serious damages to tank plating and internal structure because of the increased internal pressure or the creation of vacuum.

Generally it is desirable to use minimum amounts of estuary and river water, in order to prevent the built-up of unpumpable mud and sand in double bottom or other tank. One more reason is that maybe this water is corrosive. If it is necessary to pump in ballast from an estuary or a river, when it is safe this water must be pumped out and replaced with clean sea water and the ballast pumps must be washed out by pumping the clean water before shutdown.

The study of the stability criteria before the ballasting operation usually is carried out from the deck department and operations can be started only after written instructions from the chief engineer or the deck officer.

It must be remembered that if tanks pumped up and an overflow occurs the pressure head that take place on the tank structure and tank top will be greater than if it is run up by opening the tank connections through to the sea and filling by gravity flow.

Special care should be given if any manhole is arranged on tank top for leakage. Cargo damage maybe sustained and claims involved.

PROBLEMS WITH BALLASTING SYSTEMS: the problems associated with the removal of ballast water from a ship are similar to the problems associated with the removal of bilge water-vacuum loss due to air leaking into the system.When the surface of the water in the ballast tank has a positive head above the level of the ballast pump there is usually no problem with de-ballasting the vessel.


The problem commence when the level of the water falls to slightly above the level of the ballast pump and resistance to water flow in the suction lines causes a partial vacuum at the pump inlet branch.

When any air leakage occurs into the ballast suction line a reduction in vacuum gauge will be shown. As the vacuum is reduced, the efficiency of ballast pump falls away and the pumping action finally ceases

For centrifugal pumps a common problem occurs when the water sump becomes dry. The sump is then filled from the water filling the line and an attempt is then made to prime the pump. If this still results in failure then the float control gear and shut off valves must be examined.

Another cause of problem is if the non-return valve on discharge line stuck open and allows air to flow back down and destroy the vacuum.

VARIOUS:

The ballast system is connected to spaces which ballast water can be supplied (FPT, APT, DB, TS). The suction pipes for ballast water must be completely different from the suction pipes of the bilge system. The system should be arranged so that the water may be drawn from any tank to another tank or overboard.

When tanks are being filled by pump pressure, provision must be made to protect the structure of the tank against overpressure.

A ballast system in consisting of ballast pumps, pipes, valves and remote control of the valves. For ballasting and be-ballasting this system is normally used. For stripping purposes the pipe system is the same but the eductors are driven by another pump (G.S or Fire) and not from the ballast pumps.

INSPECTION-CHECK POINTS:

1. Check if the piping arrangement is according with the drawing.2. The ballast lines are isolated and made as a closed system by use of closing valves

and installing blind flanges. The line is filled with water until the pressures reach the test pressure (normally 1.5 times the design pressure).

3. Check for any leaks in the valves, flanges and fittings.4. Check if washers are put under the nut for all flange bolts.5. Check if tooth washers for electric conductivity, two in each flange are installed.6. Check if there is sliding shoe under the ballast lines where U-clamp is used.7. In case of GRP pipes special attention to erection joints because flame or strikes

during the welding can destroy the plastic pipe.


http://www.google.co.kr/imgres?imgurl=http://www.simerics.com/animation/centrifugal_pre_ani.gif&imgrefurl=http://www.simerics.com/gallery_centrifugal_pump.html&usg=__aaSZuDGBYHrLinQZzHkLalQG6zc=&h=270&w=280&sz=274&hl=el&start=0&zoom=1&tbnid=wTo8HHse6s9t9M:&tbnh=156&tbnw=162&prev=/images?q=centrifugal+pump&um=1&hl=el&newwindow=1&sa=N&rlz=1G1ACAW_ELKR391&biw=1282&bih=623&tbs=isch:1&um=1&itbs=1&iact=hc&vpx=149&vpy=250&dur=7005&hovh=216&hovw=224&tx=159&ty=117&ei=fDeSTPG7PJDyvQPwkvyKBA&oei=LDeSTJa5CouEvAPy26zqAw&esq=14&page=1&ndsp=17&ved=1t:429,r:6,s:0

HULL PIPING-AIR VENT SYSTEM KORDALIS KIRIAKOS

BILGE SYSTEM SPECIFICATION1. Bilge suction pipe to be provided with non-return valve and rose box (galvanized)

at open end. 2. International flange connections to be provided for bilge overboard discharge one

at each side of aft part of the vessel.3. Bilge line straight without bends as far as practicable. 4. Stainless steel bolts and nuts for non-return valves and rose boxes.5. Hydraulic butterfly to bilge well. 6. Remote control of bilge system from ballast control room. 7. Perforated division plate inside bilge well. 8. Bilge in the upper stool to be drained to adjacent cargo hold through drain holes.

CSN 1001/1005 air vent pipe is used for drainage. 9. High level float alarms and level switches to be provided. 10. Aft ship bilges to be drained through self closing valve into bilge well in engine

room.11. Fore ship bilges bilge eductor to be provided and the driving water to be taken

from fire and wash deck line with an isolating valve. 12. Pump characteristics 120/240-90/45.

RULES ABC (Machinery Part 4, Page 402)

1. A bilge system is intended to dispose water which may accumulate in spaces. It is to be capable of controlling flooding in the propulsion machinery space as a result of limited damage to piping systems.

2. It must be designed to avoid the possibility of cross flooding between the spaces and between the vessel and the sea.

3. At least two bilge pumps are provided and must be tested and certified before the delivery. Pumps that they are used for other main use on board can be acceptable in case that they are not handle oil fluids during their normal operation. The bilge pump if it is of centrifugal type must be of self-priming type. When the pump is used for one operation the others must be isolated.

4. Non-watertight compartment liable to accumulate water such chain lockers are also to be provided with an efficient bilge pumping system. A gravity drain system is also acceptable.

5. The valves must be accessible for maintenance at all times. All valves that they are connected to bilge suction must be of stop-check valve type (or non-return valve) with remote operators.

6. For combination carriers the bilge lines are to be blanked-off when oil or ballast is to be carried. To CSN 1001/1005 flash type water tight blanking is provided in case of carriage water in floodable hold 3.

7. OIL POLLUTION PREVENTION MEASURES: from machinery spaces bilges means are to be provided to process oil contaminated water before discharging it overboard (oil-water separator with alarm, permissible maximum contamination is 15 PPM). Bilges from cargo holds can be led directly to overboard connection.

8. SLUDGE TANK: is to receive oily residues from the filtering equipment or separating equipment during the purification of the fuel and lubricating oils. Heating arrangements are to be provided in case those heavy fuel oil residues are expected. The sludge pump with suitable type and capacity is provided for discharge to shore


reception facilities. No connection between sludge and bilge system is acceptable and sludge tank should not have any direct connection overboard.

The bilge system is fitted on vessels for removal of loose water from machinery. It consists by pumps, oil-water separator, piping and valves (check valves are very important for the system). The location of the bilges can be between the tank top and the side of the vessel. Drain hats are fitted on the after part of the cargo holds. The overboard outlet is monitored for oil content and an alarm is activated if the oil content approaches the allowable figure.

Non-return valves are necessary as a safety measure to prevent water flowing back into, and flooded the various compartments that are connected.

A combination of pumps can be used for emergency operation. Usually the bilge is interconnected with the pump with the greater capacity, in most cases this pump is the ballast pump. Automatic bilge piping arrangements by float switches require attention to the float control and the strainers. In cargo ship the strainers should be cleaned when the cargo hold is empty and the equipment should be tested by water added from a hose. A log book entry is necessary after the testing.

During maintenance, for example painting or chipping all rust and residuals must swept up and removed from the bilge system because they can cause serious damages to piping elements and especially to the pumps. So when the works have been carried out it is essential to clean the tank top with special care.

In case of emergency a pump must be connected with the emergency switchboard.

A typical bilge system arrangement is shown in the below sketch. The bilge system must capable of pumping from any draining and watertight compartment that it is not served by another system; like ballast tanks that they are pumped out by the ballast pump.

All bilge suctions are fitted with suitable strainers. In the engine room these will placed so that they are easily accessible from the floor plates and they should be of a type that is easily cleaned. The open area of the strainer must be at least 3 times the area of the suction pipe.

BILGE INJECTION SYSTEM:

The sketch shows a bilge injection valve. It is provided for use in the event of serious flooding of the engine room. By closing the main injection valve and opening up the bilge injection valve the largest pump or pumps in the engine room are drawing directly from the lowest point in the engine room space, this process can remove large quantities of water. A double plate is welded to the skin and machined, usually after welding operations. The chest flange being bedded into the doubler and then studded in place. A joint of either spigot and jointing compound or flat with a joint of canvas and red lead putty is used.

The diameter of the bilge injection valve is at least two thirds of the diameter of the main sea inlet. The valve spindles will be clear of the engine room platform and valves and the


operating gear will require regular examination and greasing along with cleaning of the strainer.

Typical bilge systems and troubleshooting these systems:

Components of a bilge pumping system

Trouble shooting the system

Mechanical Failure of Pump:

Pump not turning - check power source. If the pump is driven from an engine it is possible that the clutch is slipping or not engaging properly. Flexible impeller pumps shed their vanes either through old age or having been run dry. If this is the case then the impeller will need to be replaced according to manufacturer’s instructions.

Air Leaks

This is a common problem and may be caused by:

leaking glands on pump drive shafts leaking glands on valves or cocks holes in the pipework caused by mechanical damage or corrosion empty compartment valves being opened or leaking

Blocked Bilge Strainers

This is a common problem and may be caused by: leaking glands on pump drive shafts leaking glands on valves or cocks holes in the pipe work caused by mechanical damage or corrosion empty compartment valves being opened or leaking

Therefore it is important to keep the bilges clean at all times.


High bilge levels can lead to dangerous situations including:

Free surface effect on stability Fire hazard due to oil in the bilges Dangerous and explosive gases from bilges Slippery and dangerous surfaces to work on Corrosion Oil and water getting on machinery situated lower down Effect on trim, heel and draft of the ship Cleanliness Impaired visibility of lower spaces covered by bilges

Back Flooding

Back Flooding, where sea water from the sea suction floods back through the system into a bilge space or water from one bilge space floods through the system into another, is not a desirable situation and may lead to the sinking of the vessel.

Back flooding can also occur via the deck hose being left trailing over the side when the pump has stopped. Sea water can siphon back through the hose and pump into any compartments where a valve was left open. Even where non return valves are fitted, back flooding can occur where a little debris is stuck under the valve leaving it opens.

Back Flooding must be prevented at all times and is achieved by never leaving the deck hose over the side and by having non return valves in each of the bilge lines which reduce the chance of back flow into the compartments.

The strum box fitted in the holds is to be kept clean and the perforations are to be checked that they are not closed due to muck and rust. Same with the mud boxes in the ER fitted into the system.


SOUNDING SYSTEM

ABS (Part 4, Ch. 6, Sec. 4):

All tanks, cofferdams, void spaces and normally all dry compartments which are not easily accessible and they have the possibility of accumulation (adjacent to sea, or pipe passing through) are to be provided with means of sounding level. The means generally is sounding pipe or a gauge glass or both. A remote gauging system may also be accepted.

Arrangement:

1. They have to be led as straight as possible from the lower level of the compartment and normally at the after end of the tank.

2. The upper end must be accessible under all conditions of the vessel. Sounding pipes to be terminated on upper deck which is normally always accessible.

3. The internal diameter not to be less than 32 mm. 4. The termination of the sounding pipe is to be provided with a proper watertight

closing devise, permanently attached, such as a screw cap attached to the pipe with a chain.

CLOSING MEANS OF SHORT SOUNDING PIPES IN E/R

One of following automatic closing methods is required at upper end

HFO SOUNDING PIPES

1. Self closing blanking devises at ends of sounding pipes.2. Small diameter cock control located below blanking device for checking presence

of fuel oil before opening.3. Means to ensure that spillage of F.O. through control cock involves no ignition

hazard

L.O. & OTHER FLAMMABLE OILS

1. Sluice Valves or cocks with self closing means.

COFFERDAMS & OTHER TANKS

1. Sluice valves, cocks or screw caps attached to pipes by chains.

SURVEYS & TESTS DURING NEW-CONSTUCTION

A. Closing MeansB. Striking padsC. Improper bendingD. Leakage testsE. Function of self closing means


AIR VENT SYSTEM

ABS (4.6.4 Page 409)

1. All tanks served by pumps are to be provided with vents.2. The vents must locate at the highest point of the tank.3. They can be used and for overflow purposes in case that they fulfill some

requirements.4. The ends must provided with suitable means to prevent sea water from entering the

tanks through the openings.5. Small spaces that they are not permanently served by pump; may exempted from

being fitted with vents.6. Automatic means of closure are to be fitted to the outlets of the vents which will be

submerged in case of damage.7. Each tank served by a pump system should be fitted with at least two air vents. If the

area of the tank is small one vent may be acceptable.8. Vent pipes exposed on main deck are to have at least 760 mm height. For

superstructures decks 450 mm.9. Termination in machinery spaces can be within the machinery space but special

consideration should be taken in case of overflow that there is no electric equipment or hazard for fire.

10. For vents that they serve oil/lubricant service tanks they termination shall be arranged in such location that there is no risk of water ingress in case of a broken vent pipe.

11. For fuel oil tanks overflow arrangements are necessary in order to prevent pollution.


AIR PIPES TO BALLAST TANKS OR FUEL OIL TANKS

The above figure shows a design of air pipe cover.In normal condition – the ball remains at the bottom of the air pipe head and the tank breathes in and out through the vent.However in the event that the air pipe is submerged then the ball floats up and closes the opening at the top thus preventing any water from entering the tank.Sea spray and rain is prevented from entering the tank by the design of the head. It is totally enclosed and a rectangular plate, which leaves a small gap between the mesh and itself, allowing the breathing of the tank.

SURVEYS & TESTS DURING NEW-CONSTRUCTION


Number ,Position & Nameplate Height Above Deck (Measurement) Pipe head (Closing means, Gauze Wire ,Air passage hole, Function of float) LEAKAGES – To be checked at same time as tank testing or separately

GAUZE WIRE NETS FOR FIRE PROTECTION

At open ends of air pipes to F.O., Cargo Oil Tanks & adjustment cofferdams detachable corrosion resistant metal gauge (brass or stainless steel) is to be provided.

Not to be provided in ballast tanks since rusting occurs and maybe closing pipe

HULL PIPING-ENGINE ROOM PIPING KORDALIS KIRIAKOS

ENGINE ROOM PIPING

SPECIFICATION

1. The pipes to be designed to absorb stresses caused by thermal expansion and deflection of hull structure.

2. Leaking of pipe fittings should not disturb the electric gear, if it is unavoidable proper protection to be provided.

3. Pipe supports should be attached to vessel’s structural members.4. Piping to be kept away from electric equipment and flanged connections to be

arranged away from switchboard and electric fittings.5. For non-ferrous pipes, neoprene, lead or brass plate to be inserted in pipe straps6. Minimum clearance to be left around all valves, fitting and strainers to allow

overhauling without removal of the connected pipe.7. Generally slip-on flange joints to be used for steel pipe connections. For 10mm and

below to be connected by union or sleeve joint.8. Galvanized to be carried out after the fabrication and zinc rich paint to be applied to

welding damaged areas.9. Emergency shut-off valves which are fitted on the oil tank suction to be of such a

design that can be shut quickly by means of pneumatic device controlled from outside of the engine room.

PLAN APPROVAL

1. All fittings to be provided with name-plates constructed from non-corrosive material.2. Sight flow glasses on the tanks shall be on a visible position. Steps if height 2m.3. Lining of cover insulation shall not be water and/or oil pervious. Maker confirmation.4. Color code.5. No liquid pipe through ECR.6. Ship side valves of diameter 80A and less should be fitted with short piece of Sch.

160.7. Easy handling of the valves8. Miter joints bend to be used only for the exhaust pipe.9. No overboard discharge connection should in the area of lifeboat, ladder, etc.

10. Glass gauge for oil tanks should be self closing.11. Flange joints should be included to avoid long length of the pipe (less than 3m).12. Hydraulic pipes should not be arranged in bundles.13. Pressure gauges to be fitted to pressure reducing valves outlet.14. 1 spare rubber ring for every three butterfly valves.15. O2 and C2H2 gas systems’ pipes should follow segregate paths. 16. Vents and drain lines to be sloped effectively. If it is not possible a plug to be fitted for

drainage.17. Local temperature indicators should be provided with boss for F.O and L.O tanks.18. The number of sleeve joints subject to Owners satisfaction.

m.engineering -- piping systems

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