Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 5675 (1987): Specification for Rotary-disc VacuumFilters [MED 17: Chemical Engineering Plants and RelatedEquipment]

r;’ . rRRY LEVEL L

1

H

1

\ \

LIQUID

AUTOMATIC - _. . . . ._ VAI VF / .-_. _

mK

.__ --...-

8 SlUi=FINC Box/

Note - Agitator drive may also be mounted on filter frame.

FIG. 1 DIMENSIONS OF ROTARY DISC VACUUM FILTERS

IS:5675 -1987

TABLE 1 GENERAL CHARACTERISTICS AND DIMENSIONS OF ROTARY DISC VACUUM FILTERS WITH PADDLE AGITATOR

( Clause 5.1 ) -

I Dimensions Filter- ing Area

Motor Power

for Disc

Drive

Tank Capa- city up to O/F Lever

m2 kw

(3) (4) (5) (6)

Disc Dia-

meter D

m

(1)

H

mm

L

mm

(7)

S% Feed mm

(9)

mm

&e Feed mm

(8)

2 500

(11)

1 425

1 575

(10)

2 400

2 700

1’83 0’75 %: 4100 4 500 4 900 5 300 5 700

4 500 5100 5 800 6 500 7 200 7 900 8 500

5 600 6 300 7 000 7 700 8 500 9 200

10000

2 300

2’13 :5” 3”: 49 50 56

1’1 3 700 4100 4 500

z”o: 5 700 6100

4100 4 500

“5% 5 700 6100 6 500

4 500 4 900 5 300 5 700

: % 6 900

4 900

:% 6100 6 500 6 900 7 300

2 800 2 600

2 900

3 300

2’44 7 000 7 800 8 600 9 500

10300 11 200 12 000

3 000 1 730

8 600 9 600

10600 11 600 12600

:zx::

6’2

;:;

I:*: 11’7 12’8

::::i I?*: 13 500 12’5 14 500 14’0 15500 15’5 17 000 17’0 18 000 18’5

1’5

2’2

3150

3 550

2’74 ::

2 98

109 120

I 930 3 400

3 700

4 000

3’05 xi 109

:,‘; 150 164

2’2

3 900 3 600

4 200

--

3 900

2 085

3’35 117 134 150 167 184 200 218

2’2 1: %i 16000

:; % 19 500 21 000

12’5 14’0 16’0 17’5 19’0 20’5 22’0

5 300 5 700 6100

%8

:: %

2 235

Note 1 - Disc rotation speed range 0’33 to 1 rev/min or 0’17 to 0’5 rev/min.

Note 2 - Paddle agitator speed 70 to 100 rev/min Paddle agitator drive:

Dia 1’83 to 2’44 m 2’3 kW Dia 2’74 to 3’55 m 3’8 kW

Note 3 - For special application the data may be modified as agreed to between the purchaser and the manufacturer.

3

IS : 56751987

6.5.2 The automatic valve may have the provision to suck the cloth before it passes through the scrapers.

6.6 Tolerances and Runout - The face runout of the surface near the outer edge of the rotating disc shall not exceed 4 mm for discs with 2.74 m diameter and 5 mm for discs with 3.35 m diameter. The relative displacement of the cell ribs of coupled parts of the shaft shall not exceed 3 mm. The blades of the cake scrapers shall be parallel to the surface of the disc. The disparallelism on the length of the blade shall not exceed 4 mm.

6.7 The drives of the filter discs and agitators shall be made separately. The disc drive shall provide for stepless or stepped variation of disc rotation within the limits specified in Table 1. The type of drive and the variations of disc speed shall be as agreed to between the purchaser and the supplier, The electric motors for the filter drives shall be of protected construction (with moisture-proof insulation) or, if warranted, of explosion-proof construction in accordance with IS : 2148-1981 ‘Specification for flameproof enclosures of electrical apparatus ( second revision )‘.

6.8 Tank - Tank shall have provision for variable submergence of disc.

6.8.1 A leakproof sealing shall be provided between the tank and the centre shaft for hi-submergence filters, with minimum maintenance.

7. Acceptance Tests - The acceptanca test shall include the check tests consisting of inspection, measurement of dimensions and running in test for tightness between the walls and the joints at the manufacturer’s works and testing it in operation at the site of installation.

7.1 Test at the Manufacturer’s Works - The check test at the manufacturer’s works shall be conducted as follows:

a)

b)

cl 4

d

f)

The dimensions and the conditions of the surfaces of the component before and after running- in is checked.

The interchangeability of the disc sectors and the contact between the sealed surfaces in the shaft sockets is checked.

The contacting surfaces of the wear and bridge plates are checked for evenness.

The adhesion of rubber to the surface of the rubber-coated parts shall be checked by tapping with a wooden mallet. The continuity of the rubber lining shall be checked by means of the high frequency spark test as specified in 7.6.2 of IS : 4682 (Part I)-1968 ‘Code of practice for lining of vessels and equipment for chemical processes: Part 1 Rubber lining’,

Running-in test -The vacuum filter shall be tested at the maximum no-load speed of the disc and worked in the course of 6 hours. During this test, the standard of the assembly and drive of all mechanisms, disc runout and consumed power shall be checked. After running-in, examine the surfaces, shafts and bearings contacting surfaces of the wear and bridge plates and those of the gear drives.

Hydraulic tightness test-The walls and joints between the parts shall be tested for tightness before painting the filter as follows:

1) The cells of the shaft sections and the tank- by pouring in water and keeping it there for 10 minutes, and

2) Automatic valve chambers - by filling them with kerosene.

There shall be no leaks or sweating during the water test and no darkening of the chalk paste on the reverse side of the wall during the kerosene test.

7.2 Testing-in Operation -The operational test of the filter shall be made at the site of its installation. During this test, it is necessary to check the compliance of the consumed power, vacuum and its steadi- ness (as read by the vacuum gauge on the automatic valve) as well as of the other factors with the requirements of this standard and delivery specifications, and serviceability of all the mechanisms and items of vacuum filter equipment. The duration, procedure and methods of this test shall be as agreed to between the parties concerned.

8. Auxiliary Items -The equipment to be delivered shall include the following:

a)

b)

Vacuum gauges, pressure gauges, flexible vacuum hoses and control and measuring instru- ments as may be agreed to between the purchaser and the supplier:

Auxiliary equipment as may be agreed to between the purchaser and the supplier. The capacity of the vacuum pumps and air blowers as well as the volumes and diameters of the receivers and traps shall be selected from the values given in Table 2.

4

IS: 5675-1987

TABLE 2 CAPACITY AND DIAMETER OF RECEIVERS AND TRAPS

( Clause 8 )

Capacity ( sucked volume ) : 1-6 ms/h/m2 of filtering area

Air blower capacity : 0’15 m’/min/m* of filtering area

Air blower pressure : 0’35 kgf/cm*

Sucked Volume m’/min Receiver/Trap Nominal Size to be Used Dia x Height ( mm )

4‘2 250 x 600

11’3 400 x 900

28’3 600 x 900

56’7 750 x 1 200

85’0 1 050 x 1 200

122’0 1 200 x 1 200

163’0 1 350 x 1 350

204’0 1 650 x 1 650

261’0 1 850 x 1 850

326’0 2 000 x 2 000

425’0 2 300 x 2 300

482’0 2 450 x 2 450

Note ‘l - For vacuum pumps, the smaller capacity shall be taken for the suspension producing a solid non-cracking filter cake and the larger capacities for porous or cracking cake. Depending upon the properties of suspension, the vacuum shall range from 500 to 650 mm Hg.

Note 2 - Capacities of receivers/traps shown are for non-foaming filtrates with temperature below 65°C.

Note 3 - Inlet connection of receiver must be in line or below filter automatic valve connections.

Note 4 - To avoid turbulence, keep a minimum distance equivalent to 6 pipe diameters of straight pipe between any elbow and the receiver inlet flange. Use of long radius elbow is recommended.

Note 5 - Locate moisture trap 9’5 m above ground level when drained to open sump. This is called barometric leg.

9. Spare Parts - The spare parts as listed in Table 3 shall be provided by the manufacturers.

TABLE 3 SPARES FOR VACUUM FILTERS

Name of Spare Part Quantity F___---__.----A --- ------T

For Filters with For Filters wrth One Automatic Two Automatic

Valve Valves

Bridge plate, R H 1 1

Bridge plate, L H - 1

Wear plate 1 2

Flexible vacuum hose 1 2

Disc sector ( complete ) Set for one disc

Note 1 - The shut-off pipe fittings on the connecting pipe unions and the filtering cloth are not included in the standard equipment to be delivered.

Note 2 - The spare parts in excess of the quantities indicated in this table may be de!ivered on special agreement on the contracting parties.

10. Certificate - Each vacuum filter shall be supplied along with a certificate certifying its compliance with this standard and giving the following information:

a) b)

c) d) e)

Name of the manufacturer and his identification;

Serial No. of the vacuum filter;

Date of manufacture;

Results of tests, inspection and measurement; and

In addition a set of assembly drawings including lubrication charts, instructions for erection and operation of the vacuum filter shall also be supplied.

5

IS : 5675-1987

11. Designation

11.1 Rotary-disc vacuum filters shall be designated by the type, the diameter of the disc in metres and the number of this standard.

Example:

An A type filter with a disc diameter of 2’44 metres and number of disc equal to 8 shall be designated as:

Rotary Disc Vacuum Filter, Type A x 2’44 x 8, IS : 5675

12. Painting and Surface Protection

12.1 The non-machined external surfaces of the filter shall be painted with anti-corrosive paints as may be specified by the purchaser. The surfaces of the wooden discs shall be impregnated with linseed oil or coated with phenol-formaldehyde-resin-based darnish. The surface of the parts made from acid- resistant steel and rubber-coated surfaces shall not be painted. The internal surfaces of the filter tank made from carbon steel shall be painted or otherwise suitably protected as may be agreed to between the purchaser and the supplier. All the machined surfaces of vacuum filter’s parts shipped to the purchaser shall be coated with a suitable corrosion-preventive grease of fluid in accordance with IS : 1153-I 975 ‘Specification for temporary corrosion preventive, fluid, hard film, solvent deposited (first revision )’ and IS : 1674-1960 ‘Specification for temporary preventive, fluid, soft film solvent deposited’.

13. Marking, Packing and Despatch

13.1 A name-plate shall be securely fastened to the outside surface of the vacuum filter tank at the drive end at a prominent place bearing the following information:

a) Manufacturer’s identification;

b) Name and type of the vacuum filter; and

c) Serial No., year and the month of manufacture.

13. I. 1 Standard Mark - Details available with the Bureau of Indian Standards,

13.2 Packing - The vacuum filters may be shipped to the purchaser either in the assembled condition or unassembled. When shipped assembled, the vacuum filter shall be protected against damage and against the weather. When shipped unassembled, the larger components of the vacuum filter may be transported unpacked provided they are adequately protected against damage and corrosion. Smaller components, spares and instruments shall be packed in boxes to ensure protection and preservation of the parts in transit. The parts shall be marked with the number of the vacuum filter and shall bear identifying mark to facilitate assembly of the vacuum filter at the installation site. When the vacuum filter is transported with rubber-coated parts, the latter shall be protected against temperatures above 50°C.

IS:5675-1987

EXPLANATORY NOTE

This standard which was published in 1971 has been revised to modify the requirements consider- ing the new developments that have taken place during this period. The general characteristics and dimensions of rotary-disc vacuum filters as given in Tables 1 and 3 have been changed.

Rotary-disc vacuum filter is a continuous vacuum filter. It has its filter medium shaped in sectors that are assembled to make a disc. Each section is connected through a central axis or shaft to an auto- matic valve. A number of discs may be assembled on the common shaft.

Each sector has an outlet nipple that passes through the centre shaft joining a conduit running along the entire length of the shaft and terminating in a port at the automatic valve. Each serves as a filtrate channel for all sectors along the shaft of that length. Any sector may be replaced without dis- turbing the others and at slow speeds, it is necessary to stop the filter and to make the change. Filter covers are in the form of bags slipped over the sectors. The assembly of filter discs on the centre shaft is mounted in a feed tank so that the sectors are completely submerged during the cake building opera- tion of the cycle. On the discharge side, the filter tank is crenalated to accommodate the discs. The space between these divisions is utilized for cake discharge. Scrapers or tapered discharge rollers for each disc are mounted at the top of the tank. During operation, the feed is supplied from one side of the tank. The disc rotates slowly and as soon as the sectors are submerged, vacuum is applied by the action of the automatic valve. A layer of cake solids forms upon the cloth on both sides of the sectors and the filtrate passes from the sector through the conduit in the centre shaft and out through the automatic valve. Vacuum is still maintained when the sectors emerge and are exposed to the air. As each sector reaches the scrappers, the vacuum is cut off and gentle air blast is applied. This causes the filter bag to inflate since it is not held fast to the sector by any grip or wiring. Depending upon the application, air or mechanical agitator is provided at the bottom of the tank. In case of air agitation, tank is modified at the bottom to accommodate paddle agitator consisting of a pipe shaft mounted with flat blades located in between the discs.

Stuffing boxes at both ends of the shafts prevent leakage from tank sides.

In the preparation of this standard, considerable assistance has been derived from GOST 5743-63 ‘Rotary-disc vacuum filters’, issued by the State Committee on Standards, Measures and Measuring Instruments of the USSR.

7

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