Spirax Sarco DP27S Installation And Maintenance Instructions Manual
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Spirax Sarco DP27S Installation And Maintenance Instructions Manual

Pilot operated pressure reducing valves
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IM-IBR16-27IN
Issue 6
DP27S and DP27SY
Pilot Operated Pressure Reducing Valves
Installation and Maintenance Instructions
1. Safety information
2. General
product information
3. Installation
4. Commissioning
5. Maintenance
6. Spare parts
7. Fault finding
© Copyright 2016
IM-IBR16-27IN Issue 6
1
Printed in India

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Summary of Contents for Spirax Sarco DP27S

  • Page 1 IM-IBR16-27IN Issue 6 DP27S and DP27SY Pilot Operated Pressure Reducing Valves Installation and Maintenance Instructions 1. Safety information 2. General product information 3. Installation 4. Commissioning 5. Maintenance 6. Spare parts 7. Fault finding © Copyright 2016 IM-IBR16-27IN Issue 6 Printed in India...

  • Page 2: Safety Information

    Determine the correct installation situation and direction of fluid flow. iv) Spirax Sarco products are not intended to withstand external stresses that may be induced by any system to which they are fitted. It is the responsibility of the installer to consider these stresses and take adequate precautions to minimise them.

  • Page 3: Pressure Systems

    1.9 Tools and consumables Before starting work ensure that you have suitable tools and / or consumables available. Use only genuine Spirax Sarco replacement parts. 1.10 Protective clothing Consider whether you and / or others in the vicinity require any protective clothing to protect against the hazards of, for example, chemicals, high / low temperature, radiation, noise, falling objects, and dangers to eyes and face.

  • Page 4: Residual Hazards

    1.12 Handling Manual handling of large and / or heavy products may present a risk of injury. Lifting, pushing, pulling, carrying or supporting a load by bodily force can cause injury particularly to the back. You are advised to assess the risks taking into account the task, the individual, the load and the working environment and use the appropriate handling method depending on the circumstances of the work being done.

  • Page 5: General Product Information

    2.1 General description These instructions apply to the DP27S and the derivative DP27SY. The instructions primarily relate to the use of the DP27S on steam but can be used as a guide when the valve is used on compressed air.

  • Page 6: Pressure / Temperature Limits

    A-B-C Flanged ASME 150. Note: DP27S has a variable rate conical pressure adjustable spring fitted providing a downstream pressure range of 0.2 - 17 bar g. DP27SY has a pressure spring with a range of 0.2 - 3 bar g.

  • Page 7: Installation

    0.2 - 17 bar. DP27SY (Figure 1) The DP27SY is supplied as the DP27S, but has a lower rate pressure adjustment spring for a downstream pressure range of 0.2 - 3 bar. Pressure setting adjustment screw...
  • Page 8 See Section 3.6, page 9 Downstream isolating valve to provide no-load conditions for Float type setting pressure reducing valve Strainer steam trap DP27S Float type Isolation Alternative for steam trap valve draining separator Strainer Sight...

  • Page 9: Isolating Valves

    ­ ­ ­ Q Steam supply ­ ­ ­ Q ­ ­ ­ Q See Section 3.6 Fig. 3 Two pressure reducing valves in parallel 3.3 Pipeline sizing The piping on both sides of the valve must be sized so that velocities do not exceed 30 m / s. This means that a properly sized valve will often be smaller than the connecting pipework.

  • Page 10: Pressure Sensing

    1 m or 15 pipe diameters whichever is the greater. It should be arranged with a positive fall so that any condensate can drain away from the DP27S. Where the size of the reduced pressure main makes it difficult to maintain a fall when entering the top of the main, the pressure sensing pipe may be connected in the side of the main.

  • Page 11: Safety Valve

    Where a safety valve (C) is required to protect the system downstream of a DP27S and where a control valve is also being used downstream of the DP27S, it is recommended that the safety valve is fitted downstream of the control valve rather than in between the DP27S and the control valve.
  • Page 12 Section 4.1 but setting the smaller valve at a pressure higher than the larger valve. Optional bypass line (see Section 3.10) 3, 7, 8 2, 6 2, 9 Steam flow ­ ­ ­ Q Condensate ­ ­ ­ Q See Section 3.6, page 9 return Fig. 6 Setting procedure sequence DP27S IM-IBR16-27IN Issue 6...

  • Page 13: Routine Maintenance

    5. Maintenance Note: Before actioning any maintenance programme observe the 'Safety information' in Section 1. Warning: The body gasket contains a thin stainless steel support ring which may cause physical injury if not handled and disposed of correctly. 5.1 Routine maintenance It is recommended that the valve is dismantled once every twelve to eighteen months for a complete overhaul and ideally this should be carried out with the valve removed from the line.
  • Page 14 5.2 How to renew the pilot filter element 1. Isolate the reducing valve and zero the pressure. Filter 2. Unscrew the filter cap and carefully withdraw the filter element element. 3. Replace the element and tighten the filter cap to 90 - 100 N m.
  • Page 15 7. Unscrew and remove the pilot valve assembly (19 mm A/F). The pilot assembly has an integral PTFE seal. The following handling precautions should be observed. Handling precautions for PTFE Within its working temperature range PTFE is a completely inert material, but when heated to its sintering temperature it gives rise to gaseous decomposition products or fumes which can produce unpleasant effects if inhaled.
  • Page 16 Table 1 Recommended tightening torques for spring housing/actuating chamber cover securing studs and nuts Size of valve Nut size Tightening torques DN15, DN20, DN25 and DN32 40 - 50 N m DN40 and DN50 45 - 55 N m IM-IBR16-27IN Issue 6...
  • Page 17 5.5 How to clean or replace the internal strainer screen Isolate the reducing valve and zero the pressure. 13. Unscrew the unions and release the pipework. 14. Unscrew the nuts. 15. Remove the pilot valve housing; complete with spring housing assembly. 16.
  • Page 18 5.6 How to renew the pilot valve diaphragms Isolate the reducing valve and zero the pressure. 23. Unscrew the nuts and remove: spring housing, bottom spring plate and old diaphragms. 24. Ensure that all contact faces are cleaned. New diaphragms should be fitted such that the precoated sealant (which is only applied to one diaphragm) faces down contacting the sealing face of the diaphragm chamber.
  • Page 19 31. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm chamber on two bolts either side of the union connection to locate the spigot in the recess. 32. Bring the two new diaphragms together (where precoated sealant is applied this should face outwards) and slide into position.
  • Page 20 37. Remove the pilot valve housing, complete with spring housing assembly. 38. Remove the main valve plus internal strainer screen and clean. 39. Remove the main valve spring and the main valve head. Clean to remove dirt or scale as necessary. 40.
  • Page 21 Table 2 Recommended tightening torques for main valve seat Size of valve Width across flats Tightening torques DN15 and DN15 LC 30 mm A / F (External) 110 - 120 N m DN20 36 mm A / F (External) 140 - 150 N m DN25 19 mm A / F (Inside) 230 - 250 N m...
  • Page 22 48. Thoroughly clean the lower diaphragm chamber making sure contact faces are clean. 49. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm chamber on two bolts either side of the union connection to locate the spigot in the recess. 50.

  • Page 23: Spare Parts

    6. Spare parts Interchangeability of spares The following table shows how in certain sizes some parts are interchangeable. For example in the line headed 'Main diaphragm' the diaphragm used in the screwed valves ½" and ¾" is common to these sizes by the letter 'a', the letter 'c' indicates that one diaphragm is common to the DN40 and DN50 valves.
  • Page 24 Always order spares by using the description given in the column headed 'Available spares' and state the size and type of the pressure reducing valve. Example: 1 - Main valve assembly for a Spirax Sarco DN25 DP27S pilot operated pressure reducing valve. IM-IBR16-27IN Issue 6...
  • Page 25 IM-IBR16-27IN Issue 6...

  • Page 26: Fault Finding

    7. Fault finding 7.1 Preliminary procedure Before undertaking the following fault finding procedure, ensure the valve has been isolated and that upstream and downstream pressures are zero. Possible fault checks are given in a logical order below. 7.2 Downstream pressure zero or too low If downstream pressure drops below set pressure or is zero check the following: 1.
  • Page 27 7.4 Hunting Hunting may coincide with variations in steam load. If this is the case, the following checks should be made before dismantling the valve: 1. Check that the upstream pressure is stable. If the pressure drops during full-load conditions, it is possible that there is a partial blockage upstream, or that the upstream pipework is undersized.
  • Page 28 IM-IBR16-27IN Issue 6...

This manual is also suitable for:

Dp27sy

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