6.10 LUBRICATION SPTF NEED TO INCLUDE IN THIS SECTION:

A) SPECIFICATION FOR TURBINE OIL ASTM D 4304

B) OIL VISCOSITY FOR ROLLING ELEMENT BEARINGS

C) TABULATION OF DIFFERENT OIL PROPERTIES VS MFG REQUIREMENTS (ADD ON TO A&M TUTORIAL)

D)

6.10.1 Unless otherwise specified, bearings and bearing housings shall be arranged designed for oil lubrication using a mineral oil in accordance with ISO 3448 8068:1987 type AR. [API 617]

Discussion: ISO 3448:1992 only establishes a system of viscosity classification for industrial liquid lubricants and related fluids. ISO 8068:1987 specifies required characteristics of mineral oils for use as lubricants and control fluids for steam turbine systems requiring oils of category TSA and that may be used for Gas turbines using oils of category TGA. These oils are not intended for service when extreme pressure properties are required. ISO 8068:1987 references ISO 3448. ISO 8068:1987 covers ISO VG 32, 46, 68 oils and other required properties such as Kinematic viscosity, Viscosity index, Pour point, Density, Flash Point, Total Acid Number (TAN), Foaming, Air Release, Water Separabiliy, Rust-Preventing properties, Corrosiveness to copper, and Oxidation stability.

ISO 8068:1987 defines the requirements of two types of oil type AR with air release and type B with no air release requirements. Type AR has been specified.

Note 1. For the purpose of this provision, ASTM XXX is equivalent to ISO 8068:1987.

Note to TFChairmen: Refer to the note for 6.10.5 for the ISO grade of oil.

Synthetic lubricants may have advantages over mineral oils, particularly in certain classes of machinery operating at high temperatures and/or high pressures. A bearing designed for synthetics will not easily run on mineral oil lubricants due to cooling and space considerations. A user would need a relatively sophisticated inventory control system to prevent inadvertent mixing of mineral oils and synthetics., which are chemically incompatible. Synthetic lubricants may also be incompatible with certain paints and coatings and they may be difficult to dispose of.

SPTF Consider adding the following [616]4.9.2 When specified by the purchaser or required by the vendor, a synthetic lubrication oil may be used In the proposal, the vendor shall provide a complete description of the proposed system

6.10.2 For a process gas compressor, the seal-oil (if required) and lube-oil systems shall be separate or combined as specified. If separate systems are specified, the means of preventing interchange of oil between the two systems shall be described in the vendor's proposal. [5.2.3, Item k] Even with sophisticated buffer gas systems, there is usually some process gas contamination of the seal oil. if that contamination is incompatible with the lube system materials or with the lube additives (e.g. H2S attacks the tin in babbitt metal, ammonia destroys antioxidants, etc.) then the preference is for separate systems. In these cases, sour oil trap flow

should be treated as once through. (Stripping and other forms of degassing are not sufficiently effective). Sweet seal oil flow may also be contaminated occasionally by mist carryover splash, etc. along the shaft from the seals to the bearings.To prevent interchange of oil between the two systems, it is important to have equal pressures in both drain chambers. To assist in the separation, circumferential surface seals with purge or buffer gas supplied will be more effective than labyrinth type seals. [ D.Sales ISO- Sentences containing provisions must be in normal text, not part of a note.]

6.10.3 Unless otherwise specified, a pressurized oil system shall be furnished to supply oil at a suitable pressure or pressures, as applicable, to the following:a. The bearings of the driver and of the driven equipment (including any gear).b. Any continuously lubricated couplings.c. Any governor and control-oil system.d. The seal-oil system, if combined with the lube-oil system.

Discussion: This is an example where unit responsibility is required.

6.10.4 Pressurized oil systems shall be supplied in accordance with ISO 10438-1 and, as specified, ISO 10438-2, ISO 10438-3 and/or ISO 10438-4; or in accordance with API Std 614 Chapter 1 and, as specified, API Std 614 Chapters 2, 3 and/or 4. [D.Sales ISO]

Note to Task Force Chairs: If the equipment your standard covers is special purpose, require the the oil systems to be in accaordance with Chapter 1 (General) and 2(Special Purpose) and 4 (Gas seals) as specified. If the equipment your standard covers is general purpose, require the LO systems to be in accordance with Chapter 1 (General) and 3 (General Purpose). API 614 Chapter 3 also has a table with system options. You may want to standardize from this table on a default system. If TF agreement can not be obtained for a default system, just refer to Chapter 3 and let the purchaser decide what components he wants in the system.

6.10.5 Where oil is supplied from a common system to two or more components of a machinery train (such as a compressor, a gear, and a motor), the vendor having unit responsibility shall ensure compatibility of type, grade, pressure and temperature of oil for all equipment served by the common system.

6.10 5.1 The usual lubricant employed in a common oil system is a mineral oil that corresponds to ISO 3448 Grade 32. In some cases there can be significant differences in individual component needs. For example, a refrigeration compressor may need low pour point oil, a gear may need high viscosity and a turbine may need a conventional mineral oil. In such cases it may be necessary to change the design of a component or to provide separate oil systems. [ Moved note to paragraph since cant use “may” in a note. ]

Note to TF Chairmen: Suggest standardization of the ISO grade for your standard and move the grade requirement to the body of the paragraph and not in a note. For example, 617 Chapter 2 standardized on ISO VG 32 unless otherwise specified. Chapter 3 which addresses integrally geared machines allows ISO VG 46 with purchasers approval.

Discussion: For inventory control the ISO VG 32 is usually standardized as the viscosity grade of oil for SOME machinery. In certain applications with high ambient conditions an oil with

higher viscosity may be recommended by the manufacturer. For example, air cooled heat exchangers in high ambient temperature conditions which results in high oil supply temepratures. However an overriding concern from the users standpoint is the ability to inventory the minimun number of oil Viscosity Grades.

For general information, a chart of viscosity vs temperature is provided below.

For An approximate conversion of cST to SUS multiply the cST by 5 to get SUS.

6.10.6 Any points that require grease lubrication during operation and which cannot be easily and safely accessed during operation shall be provided with austenitic stainless steel extension lines terminating at one location.

Discussion: Grease life (relube interval) is typically shorter than time between machinery inspections. On-line relube is frequently necessary.

6.10.7 Pressure lubrication systems not required to be in accordance with ISO 10438 (API Standard 614) shall consist of an oil pump with a suction strainer, a supply-and-return system an oil cooler (when required), a full-flow filter, a low lube-oil pressure shutdown switch, and other necessary instruments. The requirements of 6.10.7.1 through 6.10.7.7 shall apply.

Discussion: As of this writing, API Standard 614 is being modified to include general purpose lubrication systems. When API 614 is published the need to include these paragraphs in individual standards may be eliminated.

6.10.7.1 Oil-containing pressure components not mounted inside a reservoir or sump shallbe steel.

Discussion: This is a generally required safety feature for components subjected to overheating during a fire. If the component can be expected to receive direct impingement of fire fighting water, it should not be constructed of a material which will fracture and add fuel to the fire. Steel is ductile and will not fracture. Cast and ductile iron, the more common and less expensive alternative could fail and add fuel to the fire.

6.10.7.2 Unless otherwise specified, a shaft driven main oil pump shall be provided.Note to TF Chairmen: Review and tailor this requirement to the specific type of machinery under consideration.

Discussion: If the shaft driven pump fails, it will result in the need to shut down the machinery train. Particular care needs to be given to the design of any lubrication system with a shaft driven pump. Suction piping design and layout is often critical. Standardized designs with known operating characteristics are often quite reliable. Custom engineered systems are prone to reliability problems and/or failure.

6.10.7.3 If specified or if required by the vendor, a hand-operated standby pump shallbe provided.

Discussion: This pump is sometimes required for pre-lube (prior to starting) or for hand turning during periods of idleness and maintenance. Standby pumps may also be necessary to prime a shaft driven pump. For most machines with hydrodynamic bearings, a pressurized oil supply prior to startup is essential.

6.10.7.4 If specified, or for equipment that will operate at idling speeds or will require rapid starting, a separately-driven, automatically-controlled standby pump of the same capacity as the main pump shall be provided.

Discussion: The lube oil system needs to be up and running with warm oil for fast starting of many types of machinery. Shaft driven oil pumps will not provide enough oil during rapid startup. To maintain high machinery reliability, a standby pump is usually required.

An overhead gravity lube oil supply should be provided for rundown protection in the event of loss of oil supply pump(s); for example when both pumps are driven by AC motors and both take power from the same feeder and/or motor control center (MCC). For high reliability in cases where both pumps are AC motor driven. one common configuration is to have each motor connected to a separate MCC and each MCC supplied by a separate transformer and feeder. An overhead gravity tank may also be required to maintain the oil supply while a standby pump is starting up and establishing the required pressure.

6.10.7.5 Oil Cooler

An oil cooler shall be provided in accordance with 6.10.7.5.1 through 6.10.7.5.8.

6.10.7.5.1 General

6.10.7.5.1.1Each oil cooler shall maintain the oil supply temperature at or below 50 °C (120 °F). The cooler shall be water-cooled, shell-and-tube type or plate type or air-cooled type, as specified. Coolers shall be in accordance with the standard specified. Internal oil coolers shall not be used.[D.Sale – ISO]

The vendor shall include in the proposal complete details of any proposed shell-and-tube type, plate type or air-cooled type cooler.

Discussion: 120 °F is a typical design requirement for bearings to prevent condensation and to provide enough mobility to distribute oil adequately. The 120 °F design temperature is usually based on the maximum ambient temperature and normal cooling water temperatures and flows.

Tube-sides of shell-and-tube type coolers are easier to clean than shell-sides. Water is more prone to fouling than the lube oil.

Internal oil coolers are difficult to maintain, prone to leaks and cannot be easily uprated. The machine must be shut down to work on them.

API Standards 661 (for air coolers) and 662 (for plate coolers) were not referenced as design standards because these standards are intended for process application and they result in an over-design for a general purpose lubrication system.

Plate type coolers offer space saving advantages. One disadvantage is the disassembly required for maintenance. Due to small cooling water passages, plate type coolers plug more easily than shell-and-tube designs. Maintenance is therefore highly dependent on cooling water quality.

6.10.7.5.2 Each cooler shall be sized to accommodate the total cooling load.

6.10.7.5.3 An oil bypass line around the cooler with a temperature control valve shall be included to regulate the oil supply temeperature. This includes oil systems where the purchaser supplies the cooler. In no case however shall the oil bypass the filter. The control valve shall be in accordance with 6.10.7.3.1 through 6.10.7.5.3.4 [API 614]

Note: When fouling or freezing of the water side of a cooler is a factor, and oil temperature is regulated by adjusting water flow through the cooler, it is possible for the water side to silt up or freeze and break at low water flow rates. [API 614]

6.10.7.5.3.1 Unless otherwise specified, the oil bypass valve shall be flanged and pneumatically oprated (air-to-open, fail close), two-port or three port temperature control valve. Failure of the control valve shall cause all oil to pass through the cooler. [API 614]

6.10.7.5.3.2 If specified, the temperature control valve shall be an internal, thermostatically-operated three-port valve. [API 614]

6.10.7.5.3.3 The temperature control valve shall be provided with a manual override that permits operation independent of temperature conditions. [API 614]

6.10.7.5.3.4 The temperature control valve and piping shall be sized to handle all oil flow passing through the cooler. For a three-way temperature control valve, the pressure drop should not exceed that through the cooler. For a two-way temperature control valve, pressure drop should not exceed 50% of th pressure drop through the cooler. [API 614]

An oil temperature control system with a manual over-ride or bypass shall be provided. For water cooled services, this system shall be based on an arrangement by which a portion of the oil flow bypasses the cooler to maintain constant oil temperature to the equipment. Control valves shall be of flanged steel construction. [9.2.3, Item k]

Discussion: For water cooled services, this arrangement allows bypassing the oil cooler without the need to reduce cooling water flow rates. This helps avoid fouling of the cooling water side at low flow rates. It is also a simpler, less costly type of temperature control arrangement. Normally, fan control and louver adjustment is used to control air-coolers.

6.10.7.5.4 Shell-and-tube coolers shall have water on the tube side. With purchasers approval, for applications with oil pressures greater than 3 450 kPa (34,5 bar) (500 psi), oil may be on the tube side. Unless otherwise specified, a removable-bundle design is required for coolers with more than 0,5 m2 (5 ft2) of surface. Removable-bundle coolers shall be in accordance with TEMA Class C or other heat exchanger code specified and shall be constructed with a removable channel cover. Nominal tube outside diameter shall be at least l6 mm (5/8 in) and nominal tube wall thickness shall be at least l8 BWG [1,2 mm (0.050 in)]. U-bend tubes may be supplied with purchaser's approval. [API 614]

Discussion: TEAM C is generally considered minimum construction robustness for reliable continuous service. Removable bundles are required for larger size bundles. For small bundles less than 0.5 square meters, it is often more economical to replace the entire cooler than require a removable bundle design. Channel cover designs allow good access for tube cleaning. Tubes smaller than l6mm are difficult to mechanically clean. Tubes thicknesses of 18 BWG or less are more prone to mechanical damage when cleaning by hydroblast and when handling. U-tubes are difficult to mechanically clean but may be chemically cleaned in smaller sized coolers.

Discussion: For high pressure applications, it may be more economical to place the oil inside the tubes and not require the cooler casing to be capable of the 500 psi oil.[API 614]

6.10.7.5.5 Unless otherwise specified, cooler shells, channels, and covers shall be of steel; tube sheets shall be of brass; and tubes shall be of a copper/zinc/tin non-ferrous material such asin accordance with UNS C44300 (ASTM B-111???) (inhibited admiralty) or other internationally recognized standard as approved by the purchaser..Note: Alternative materials should be considered for salt and brackish water services. Tube materials such as 90-10 copper-nickel may can be an appropriate choice for such services. [The use of the word “may” is not appropriate for use in a NOTE since it implies “permission” to perform a requirement, and requirements are not allowed in a NOTE. The use of the word “can” is used to indicate a possibility and is therefore not a requirement and is appropriately used in a NOTE. [ISO Directives Part 2 Annex G paragraph G.3].

Note: High-pressure oil coolers can require steel tubes and tubesheets.

Discussion: Steel covers are robust and resist rough handling. Brass tube sheets are desirable for corrosion resistance. Naval brasses (60/40/1 % and 70/30/1 % copper/zinc/tin) are particularly resistant to impingement of high velocity water and are commonly used in marine condensers. An alternate choice is one of the aluminum bronze materials. Stainless steel lubes are generally not recommended because of chloride cracking problems in salt and brackish water services and poorer heat transfer characteristics.

6.10.7.5.6 To prevent the oil from being contaminated if the cooler fails, the oil-side operating pressure shall be higher than the water-side operating pressure.

6.10.7.5.7 Both the water side and oil side of the cooler shall be self-venting and self-draining or shall be completely drainable on the water and oil sides with valved vent and drain connections.Coolers shall be equipped with high point vent and low point drain connections on their oil side and water side (when applicable). [API 614]

Discussion: The requirement for vent and drain connections is included to prevent manufacturers from requiring the user to break a flanged connection to accomplish venting and draining operations. Valved connections are not specifically required for small general purpose lubrication system equipment. If valved connections are needed, the requirement should be added.

6.10.7.5.8 Oil coolers shall not be located inside the reservoir.

6.10.7.5.9 If specified, shell and tube or plate frame coolers shall be suitable for use of a 150 ºC (300 ºF) heating medium. [API 614] Note Steam may be used for auxiliary heating on startup by sparging it intothe cooling water. Live steam should not be introduced directly into the cooler. [API 614] [ moved note to paragraph since it contained a provision –Per D. Sales ISO]

4.5.3 Multi-plate type coolers

4.5.3.1 If specified, and in addition to the requirements of the general cooler section 6.10.7.5 , multi-plate type coolers shall be in accordance with 4.5.3.2 and. 4.5.3.3

4.5.3.2 Multi-plate coolers shall have plates of austenitic stainless steel for fresh water cooling or titanium for brackish or salt water, or as specified by the purchaser.

4.5.3.3 To prevent the oil from being contaminated if the cooler fails, the oil-side operating pressure shall be higher than the water-side operating pressure. Covered in 6.10.7.5.6

4.5.4 Fin fan coolers4.5.4.1 Air-cooled heat exchangers are not often required on these systems and, if provided, their details are usually specified by the purchaser. When a detailed specification is not available, guidance is provided in 4.5.4.2 through 4.5.4.8.

4.5.4.2 Fin  fan coolers shall meet the requirements of the general cooler section 6.10.7.5

4.5.4.3 The cooler shall be provided with two fans. Each fan shall be capable of 100 percent of the duty requirement

4.5.4.4  If specified the cooler tubes shall be series 300 stainless steel.

4.5.4.5  If specified the header boxes shall be made of hardened stainless steel plate, The header plug material shall be selected to prevent galling.

4.5.4.6 Two separate headers shall be provided for each cooler.

4.5.4.7  Electronic vibration switches shall be provided for each fan and shall alarm on high vibration.

4.5.4.8 Belt drives shall meet the requirements of 7.3

4.5.4.9 Turbulance promotors may only be used with purchaser approval. When supplied turbulance promotors shall be 300 series stainless steel.

6.10.7.6 Filters

6.10.7.6.1 Full-flow filters with replaceable elements located downstream of the cooler shall be supplied. Filters shall not be equipped with a differential pressure limiting valve or any automatic bypass arrangement which can cause bypass of unfiltered (dirty) oil around the filter elements. Any filter having a cover with a mass greater than 15 kg (35 lb) shall be provided with a mechanical lifting device for removing the cover.

Discussion: Oil cleanliness is essential to machinery reliability. To ensure cleanliness, filters should be the last piece of equipment in the oil system before oil enters the machine. Integral relief valves typically cannot be checked on standard maintenance shop test rigs.

6.10.7.6.2 If specified, or if systems include aluminum or microbabbitted bearings, filtration shall be 10 microns or finer. Other systems shall be provided with filtration of 25 microns or

finer. Filters shall remove at least 90 % of the particles with a size equal to the specified micron rating.Note To avoid confusion, the terms nominal and absolute filter ratings are avoided. Filter cartridge or element micron rating is based on 90% efficiency. Micron particle size implies the shape of a spherical bead; thus, a l0-micron particle is a sphere with a diameter of l0 microns. Within the element's recommended maximum pressure drop, l0 microns implies that the efficiency of the filter on particles that are l0 microns or larger in diameter will be no less than 90% for the life of the element.

Discussion: For in-depth discussion of filter performance, Beta ratio, ISO cleanliness code and associated terms should be referenced.

Cleanliness of lube oil systems is one of the most important factors affecting machinery bearing life. For optimum life of a typical hydrodynamic bearing, a filter which will keep the system to a cleanliness level of ISO Code 18/14 (which is equivalent to 2 000 particles under IS micron size and 100 particles over IS micron size) is desirable.

25 micron filtration is standard for systems supplying babbitted bearings where oil films are a minimum of 25 micron (0.001-in) and bearings have good embeddability characteristics. However, 25 micron filtration is generally insufficient to minimize silt buildup within the oil system.

Aluminum alloy bearing surfaces do not have the embeddability of babbitt metal and are therefore less tolerant to contaminants. These contaminants partially embed and score the mating surface of the journal. Solid particulate erosion is sharply reduced by keeping maximum particle size less than 40% of the minimum film thickness.

Microbabbitt bearings have a very thin layer of babbitt [approximately 400 (0.015-in)]. and relatively poor embeddability. Systems providing oil to these bearings need to be as clean as systems providing oil to aluminum alloy bearings.

6.10.7.6.3 Filter cartridge materials shall be water and corrosion resistant. Filter cartridges shall be resistant to deterioration by water up to a water-in-oil volume fraction of 5 %, and shall be suitable for operating temperatures up to 70 °C (160 °F). Metal-mesh or sintered-metal elements shall not be used. If specified, filters shall be designed to use filter elements or cartridges of the make, model number and type of construction specified. [David Sales ISO]

Discussion: Typically, oil systems operate with water contamination levels in the range of one percent or less and operating temperatures of 60 °C (140 °F) or less. Requiring filter cartridges to perform at water contamination levels up to five percent provides enough margin to avoid equipment upsets in machinery such as steam turbine drives.

Metal-mesh and sintered-metal filter cartridges are prone to plugging. Corrosion of the media causes internal plugging, collapse, potential contamination of the oil system and makes cleaning very difficult.

6.10.7.6.4 Oil flow shall be from the outside toward the center of the filter cartridge or cartridges. Filter elements shall be supported to prevent them from rupturing and to prevent unfiltered (dirty) oil from bypassing the elements. Design of the complete filter, including the filter/cartridge components shall ensure proper assembly so that internal bypassing cannot occur. All components (excluding the filter cases and heads) in contact with filtered oil shall be made of stainless steel.

Discussion: Prevents bypassing due to poor fit up. Stacked cartridges have the potential of bypassing. One-piece cartridges minimize this problem. All filter and cartridge design and assembly features need to address potential filter-to-cartridge or cartridge-to-cartridge misalignment problems, inadequate end cover sealing and other deficiencies which can result in bypassing.

Filter cases and heads are not significantly in contact with filtered oil. Therefore, there is no need for these components to be stainless steel.

6.10.7.6.5 The pressure drop for clean filter elements or cartridges shall not exceed 0.30 bar (5 psi) at an operating temperature of 40°C (100°F) and normal flow.

NOTE 1   Pressure drop across the total filter system may exceed these values by the amount of pressure drop across the transfer valve and other filter system components.

NOTE 2 The 0.30 bar (5 psi) is the difference between the drop across the filter housing with no elements installed, and the drop across the filter housing with clean elements installed.Cartridges shall have a minimum collapsing differential pressure of 5,0 bar (70 psi). [API 614]

Discussion: 15% yields a pressure drop ratio of about 6 from clean to dirty. This gives a adequate life between replacements. 5 bar (70 psi) provides a suitable margin in excess of2,5 bar (35 psi) differential pressure limiting device or relief valve plus accumulation to avoid accidental collapse of elements.

6.10.7.6.6 For systems with centrifugal oil pumps, filter cases and heads shall be suitable for operation at the maximum pump discharge pressure with the pump running at driver-trip speed. For systems with positive displacement pumps, filter cases and heads shall be suitable for operation at a pressure not less than the pressure limiting device setting.

Discussion: Pressure limiting device (modulating type valve) terminology is used because these devices do not open instantaneously. Conversely, pressure relief valves (snap acting type valves) open instantaneously and normally do not reset at the same relief pressure. Frequently, pressure relief valves reset at a substantially lower pressure—sometimes below the trip pressure level.

6.10.7.6.7 The filters shall be equipped with valved vents and clean- and dirty-side valved drain connections. The dirty-side connections shall be located lower in the housing than the filter elements or cartridge support bases to allow complete drainage of the dirty side [614 4.6.1.6]

6.10.7.6.8 Unless otherwise specified, dual filters shall be supplied, complete with a separate or integral continuous flow transfer valve (or coupled pair of valves) that provides tight-shut-off of

the idle filter. The system shall be designed to permit cartridge replacement and repressuring during operation.

6.10.7.7 If specified, a removable steam-heating element external to the oil reservoir or a thermostatically controlled electric immersion heater with a sheath of austenitic stainless steel shall be provided for heating the charge capacity of oil before start-up in cold weather of the equipment being supplied by the oil system. The heating device shall have sufficient capacity to heat the oil from the specified minimum site ambient temperature to the lubricated equipment’s required start-up temperature within 12 hours. The heat flux through surfaces in contact with the oil shall not exceed 2,3 W/cm2 (15 W/in2).[D Sales ISO]

Discussion: A sheath is not a can. Generally, a can is not used in general purpose lubrication system heater designs. If a can is used. it must be carefully designed to avoid high internal temperatures.

In cold weather conditions, lube oil charges in exposed reservoirs can get cold and very viscous. One of the most effective ways to deal with this problem is to heat the oil to make it less viscous. Under cold weather conditions, the lube oil pump may not be able to move the oil through the system. Also, the power required by the lube oil pump may be excessive and pressure limiting device sizing may be inadequate to prevent the discharge pressure from exceeding the equipment rating. Lube oil pumps are sized for 10 °C (50 °F) oil. If site temperatures are lower than 10 °C (50 °F). the oil in the reservoir needs to be heated to 10 °C (50 °F) before starting the pump.

Heaters may also be used to maintain oil reservoir temperature. Maintaining bulk oil in the reservoir at 50 °C (120 °F) aids the separation of water condensation.

Limiting heat flux prevents oil coking due to locally high temperatures. Twelve hours is a practical and commonly agreed-upon time period to heat the reservoir oil. If much more rapid heatup is used, it results in excessively high heat fluxes and oil coking problems.

6.10.7.8 The oil reservoir shall:a) be constructed of austenitic stainless steel unless it is an integral part of the machine being

served or is built into the baseplate;b) have sufficient capacity to avoid the need for frequent refilling, to provide adequate

allowance for system rundown, and to provide a retention time of at least 3 min;c) have provisions to eliminate air and to avoid foreign matter being drawn into the pump

suction;d) have filling connections, an armoured weld pad oil level sight glass (with maximum and

minimum levels permanently marked or indicated) and breathers suitable for outdoor use;e) have a sloping bottom and connections for complete drainage;f) have cleanout openings as large as practicable. [Rearranged and reworded per David Sales

recommendatons ISO]

Discussion: With residence times of less than 3 minutes, complete disengagement of air cannot be ensured under all oil system operating conditions and air will be drawn into the

pump and downstream equipment. Subsequent separation of air may interfere with the proper functioning of filters, coolers. and control systems.

SPTF Add filter/breather requirement from 614 with the following discussion:

Discussion: From the "Lubrication Excellence 2004 Conference Proceedings"

(An excerpt from the "Best Practices in Bulk Lubricant Storage and Handling" paper.)

Above the tank's oil level and beneath the roof of the same tank lies the headspace. Every tank produces different conditions within its headspace as the contents of oil mist, dirt and water vapor vary considerably. A high percentage of moisture and solid contaminants that enter lubricating oils and hydraulic fluids in storage vessels must pass through the headspace.

Breathers are necessary to exclude contamination. The breather needs to have a particle size and capture efficiency similar to what the transfer oil filter is expected to have. For example, if the oil filter that is used when discharging the lubricant out of the tank has a 10-micron filter and 90 percent capture efficiency (Beta 10 = 10), then the breather performance should be the same or better. If the lubricant is a hydraulic fluid, then the breather usually requires fine breather filtration - around 3 microns. Gear oils by comparison may need only 10- to 20-micron filters at 90 percent capture efficiency.

6.10.8 Oil disks and oil rings shall be metal and shall have an operating submergence of3mm to 6 mm (1/8 in to 1/4 in) above the lower edge of the disk or above the lower edge of the bore of an oil ring. Oil disks shall have mounting hubs to maintain concentricity and shall be positively secured to the shaft.

Discussion: Oil rings and disks are simple pumping devices to provide lubrication by transporting oil from a local bearing housing oil drainage reservoir to the shaft (oil ring) or an upper reservoir (oil disk). The amount of submergence is critical. Too little submergence of an oil ring results in the ring skipping on the oil surface and loss of efficiency in picking up oil. Too much submergence results in excessive drag on the ring. The ring will run at less than normal speed or will stops resulting in shaft wear. Also, if the ring runs at less than normal speed it can result in oil starvation.

Oil flingers (slingers) are used to prevent oil migration along a shaft, not as a means of transporting oil.