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Summary of Contents for Forbes Marshall FMPRV41
- Page 1 Installation and Maintenance Manual Forbes Marshall Pilot Operated Pressure Reducing Valve FMPRV41 Energy Conservation | Environment | Process Efficiency www.forbesmarshall.com...
- Page 2 PLEASE NOTE - Throughout this manual this cautionary symbol is used to describe a potential damage or injury that might occur if the safety considerations are overlooked. This symbol denotes CAUTION, WARNING or DANGER. Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 3 The product is suitable for use as defined in the technical information sheet. In case the need arises to use the product on any other fluid please contact Forbes Marshall for assistance.
- Page 4 2.10 Returning products: Customers and Stockist are reminded that, when returning products to Forbes Marshall they must provide information on any hazards and the precautions to be taken due to contamination residues or mechanical damage which may present a health, safety or environmental risk.
- Page 5 Brief Product Information: 3.1 Description: The Forbes Marshall Pilot Operated Forbes Marshall Pilot Operated Pressure Reducing Valve, FMPRV41 is a SG iron pilot operated Forbes Marshall Pilot Operated Pressure Reducing Valve suitable for steam or compressed air. 3.2 Sizes and End Connections:...
- Page 6 Figure 1: Forbes Marshall Pilot Oprated Presure Reducing valve - FMPRV41 steam. Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 7 27 Main diaphragm pad SS Type 304 ASTM A240 28 Lower diaphragm pad SS Type 304 ASTM A276 29 Pushrod SS Type 431 30 Lock nut SS Type 316 31 Control pipe assembly SS Type 304 ASTM A213 32 Name plate FMPRV41...
- Page 8 Screwed A Flanged A1 DN15 ..DN15 LC ..DN20 ..DN25 ..DN40 ..DN50 ..FMPRV41 STEAM Figure 2: Dimensional drawing of FMPRV41-STEAM FMPRV41 (Air) Size Screwed A Flanged A1 ..DN15 LC ..DN20 ..DN25 ..DN40 ..
- Page 9 6 bar g upstream pressure line crosses the horizontal 4 bar g downstream pressure line. A perpendicular dropped from this point gives the capacities of all FMPRV41 sizes under these conditions. Superheated steam Because of the higher specific volume of superheated steam a correction factor must be applied to the figure obtained from the chart above.
- Page 10 SIZE DN15 DN20 DN25 DN40 DN50 For conversion Cv (UK)=Kv x 0.963 Cv (US)=Kv x 1.156 Compressed Air Capacity Chart Upstream pressure bar g Figure 5: FMPRV 41 Sizing (air application) Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 11 Product Working Principle: [Refer to Figure 1] A Forbes Marshall Pilot Operated Pressure Reducing Valve balances the downstream pressure through the pressure sensing pipe (23) against the pressure adjustment control spring (5). This in turn moves the pilot valve plunger (10) in the pilot valve assembly (10, 11, 12, 13 and 14), to modulate a control pressure which is directly proportional to the pilot valve opening.
- Page 12 8. Figure 6: Recommended installation of FMPRV41 *This is a typical representation of Forbes Marshall Pilot Operated Pressure Reducing Valve Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 13 Fig. 7: Installation of Two FMPRV41 in parallel *This is a typical representation of Forbes Marshall Pilot Operated Pressure Reducing Valve Figure 8: Installation of Two FMPRV41 in series *This is a typical representation of Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 14 5.2 Pipeline sizing: The piping on both sides of the valve must be sized so that velocities do not exceed 30 m/s. normally, a correctly sized FMPRV41 will be smaller than the connecting pipe work. 5.3 Pipeline stresses: Line stresses caused by expansion or inadequate support should not be imposed on the valve body.
- Page 15 It should be arranged with a positive fall so that any condensate can drain away from the FMPRV41.Where the size of the reduced pressure main makes it difficult to maintain a fall when entering the top of the main, the pressure control pipe may be connected in the side of the main.
- Page 16 Where a safety valve is required to protect the process system downstream of a FMPRV41 and where a temperature control valve is also being used downstream of the FMPRV41, it is recommended that the safety valve is fitted downstream of the temperature control valve rather than in between the FMPRV41 and the temperature control valve.
- Page 17 Check that the pressure gauge isolating valve (13) are open. For correct operation of the FMPRV41 (5) it is important that the pilot and main valves are not subjected to dirt or other hard particles .Therefore, prior to bringing the...
- Page 18 Clean Pilot valve chamber assembly kit Check & clean Main / Pilot diaphragm Clean SS tube & stud coupling with split pin Main valve cleaning FMPRV41 overhauling and push rod checking Pilot Valve chamber Strainer Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 19 7.2 Tool Kit: To carry out maintenance of the Forbes Marshall Pilot Operated Pressure Reducing Valve FMPRV41 refer the tools mentioned in the table below. Size Component Tool used and Size DN 15 / Main valve seat assembly Ring spanner 36 mm (A/F) Veriner to measure depth &...
- Page 20 Remove and replace the pressure adjustment spring (4) and the top spring plate (5). Reassemble in reverse order. Adjustment Screw (1) Adjustment Locknut (2) Spring Housing securing Nuts and Bolts (3) Top Spring Plate Adjustment Spring (4) Figure 11: Pressure adjustment spring Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 21 Straight edge Spring (3) Spring Hsg.securing nuts and bolts (2) Bottom Spring Plate (5) Pilot Diaphragms (6) Plunger (8) Pilot Valve Assembly (7) Unions of balancing Unions of pipe (1) balancing pipe (1) Figure 12: Pilot valve assembly FMPRV41 steam FMPRV41...
- Page 22 45-55 Nm Table 1 : Recommended tightening torques for spring housing nuts 7.6 Procedure to renew the pilot valve assembly for FMPRV41 air: ( Refer to fig.13 & 14) Isolate the reducing valve and zero the pressure. Unscrew the unions of balancing pipe and controlling pipe (1) and release the pipe work.
- Page 23 Ensure the sharp edges formed as a result of machining are removed, as these can damage the diaphragm. 7.7 Procedure to clean or replace the internal strainer screen: (FMPRV41 Steam / Air) (Refer to Figure 15) Isolate the reducing valve and zero the pressure.
- Page 24 Main Valve return spring (6) Figure 15: Procedure to clean or replace the internal strainer screen 7.8 Procedure to renew the pilot valve diaphragms: (FMPRV41 Steam/Air) (Refer to Figure 16) Isolate the reducing valve and zero the pressure. Unscrew the unions of balancing pipe and controlling pipe (1) and release the pipe work...
- Page 25 Bring the valve back into commission, following as many steps as necessary in section 6 M12 nuts and bolts (2) Push Rod assembly (6) 17 (a) Diaphragm Plate (5) Main Diaphragms (4) Union nut (1) Lower Diaphragm Chamber (3) 17 (c) 17 (a) Figure 17: Main Diaphragms FMPRV41...
- Page 26 7.10 Procedure to service or renew the main valve and seat (FMPRV41 Steam/Air): (Refer to Figure 18, 19 and 20) Isolate the reducing valve and zero the pressure. For this section refer to figure 18 Unscrew the unions of balancing pipe and controlling pipe (1) and release the pipe...
- Page 27 (2) and pushrod assembly (5). M12 nuts and bolts (1) Push Rod assembly (5) Diaphragm Plate (2) Main Diaphragms (3) Lower Diaphragm Chamber (4) Figure 20: Resetting the main valve pushrod Table 2: TORQUE FOR MAIN VALVE SEAT FMPRV41 STEAM/AIR FMPRV41...
- Page 28 Refit the main valve head, make sure valve locates on seat. Check the valve lift shown in Table 3 using a depth gauge and adjust if necessary byscrewing the pushrod in or out of the diaphragm plate. Table 3 : VALVE LIFT FMPRV41 STEAM/AIR Size of Valve Valve Lift...
- Page 29 Replace the main valve return spring (2). Fit a new gasket (1). Replace the internal strainer screen (5). FMPRV41 - Steam Assemble the pilot valve housing complete with spring housing assembly and tighten the nuts to the recommended torques. FMPRV41 - AIR Assemble the pilot valve housing and tighten the nuts to the recommended torques Refit the pipework and retighten the unions (4) to ensure a tight seal.
- Page 30 A pressure reducing valve typically has the following failure modes: Downstream pressure zero or too low: If downstream pressure of Forbes Marshall Pilot Operated Pressure Reducing Valve is zero, please check following before dismantling the Forbes Marshall Pilot Operated Pressure Reducing Valve.
- Page 31 Downstream pressure is equal to upstream pressure: If downstream pressure of Forbes Marshall Pilot Operated Pressure Reducing Valve is equal to upstream pressure, please check following before dismantling the Forbes Marshall Pilot Operated Pressure Reducing Valve. By Pass isolation valve: - Please ensure that it should not be leaking & should be in full closed condition.
- Page 32 Hunting: Hunting or Pressure Fluctuations may coincide with variations in steam load. In such case, check following before dismantling the Forbes Marshall Pilot Operated Pressure Reducing Valve. WET Steam- Ensure steam is not wet and Moisture separator is installed before the pressure reducing valve &...
- Page 33 Available Spares: STEAM STEAM Push rod assembly STEAM Figure 23: Parts Available as spares (Heavy outline ) for FMPRV41 FMPRV41...
- Page 34 Control Pipe Assembly Kit DN 50 S2055888 Control Pipe Assembly Kit DN 15/20 S2019606 Control Pipe Assembly Kit DN 25 S2019607 Control Pipe Assembly Kit DN 40 S2019608 Control Pipe Assembly Kit DN 50 S2019609 Forbes Marshall Pilot Operated Pressure Reducing Valve...
- Page 35 S2055939 How to Order: 1 no. Forbes Marshall Pilot Operated Forbes Marshall Pilot Operated Pressure Reducing Valve, DN 40 FMPRV41 having a 0.2-17 bar g spring and flanged BS10 table “F/H” connections. Warranty Period: As per the ordering information and agreement in the contract.
- Page 36 Any dissemination, use, review, distribution, printing or copying is strictly prohibited, if you are not the intended recipient or user of this information. Forbes Marshall Pvt Ltd Manufacturing: B-85, Phase II Chakan Indl Area, Sawardari, Chakan Tal.
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