UK Product Handbook 2026 - Volume 1

44

Control systems Pressure reducing/surplussing valves

Pressure/temperature limits

A

B

C

Body design conditions

PN40

Maximum design pressure

40 bar g @ 50 °C

Steam saturation curve

DRV4 300 °C @ 25.8 bar g DRV4G 90 °C @ 37.3 bar g

Maximum design temperature

F

F

E

D

Minimum design temperature

0 °C

Pressure bar g

DRV4 300 °C @ 25.8 bar g DRV4G 90 °C @ 37.3 bar g

Maximum operating temperature

The product must not be used in this region.

Minimum operating temperature 0 °C Note: For lower operating temperatures consult Spirax Sarco

A-C-D Flanged EN 1092 PN40 and ASME 300.

A-B-E Flanged ASME 150.

DN15 - DN50

25 bar

Maximum differential pressure

DN65 - DN100 20 bar Designed for a maximum cold hydraulic test pressure of 60 bar g Note: With internals fitted, test pressure must not exceed 40 bar g

F-F The DRV4G is limited to 90 °C.

4.6 36

Materials

No.

Part

Material

1 2 3

Body

Cast steel

GP 240 GH

Bonnet

Cast steel

DIN 17425 GS C25

Valve seat

Stainless steel

BS 970 431 S29

DN15

Stainless steel

4

Seat gasket

DN20 and DN25

Mild steel

DN32 to DN50

Reinforced exfoiliated graphite

DRV4

Stainless steel

BS 970 431 S29

5

Valve head

DRV4G (soft seated)

Stainless steel/Nitrile

BS 970 431 S29

6 7 8 9

Valve head screw

DN15 and DN20

Stainless steel

BS 6105 A2

Valve head seal

Arlon 1555

Bush

DN15 and DN20

Stainless steel

BS 970 431 S29

Bush (part of item 10)

DN25 to DN100

Stainless steel

BS 970 431 S29

10

Balancing bellows assembly DN25 to DN100

Stainless steel

AISI 316 (L)

11

Balancing bellows gasket

DN25 to DN100

Reinforced exfoiliated graphite

12 13

Bonnet gasket

Reinforced exfoiliated graphite

Bonnet nuts

Steel

DIN 267 Pt13 Gr. 8

DN15 to DN40

M10

14

Bonnet studs

DN50 and DN65

M12

Steel

DIN 267 Pt13 Gr. 8.8

DN80 and DN100

M16

15

Pillars

Steel zinc plated

BS 970 230 M07

16

Pillars nuts

Steel zinc plated

BS 3693 Gr. 8

17

Spring adjuster

Cast iron zinc plated

DIN 1691 GG 25

TI-P203-01 CTLS Issue 19

Page 2 of 11

DRV4 and DRV4G Cast Steel Pressure Reducing Valves

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