A

B

C

Steam

saturation

curve

A

B

C

4.1.97

Control valves

Control valves

Pressure / temperature limits

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A - A

B - B

C - C

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Pressure bar g

Maximum operating pressure on saturated steam

Maximum operating pressure on size 2"

Maximum operating pressure on sizes 1⁄2" to 11⁄2"

9 bar g

16 bar g

25 bar g

Body design conditions

Screwed BSP or NPT

1⁄2" - 11⁄2"

2"

PN25

PN16

25 bar g

180°C

-10°C

9 bar @ 180°C

180°C

-10°C

60°C

-10°C

(see page 4)

1.5 x PMA (PN rating)

ANSI class V1

On/off

Port 1 to 2

Port 2 to 1

Port 1 to 2

Port 2 to 1

60°C maximum

10 bar g

10 bar g

8 bar g

PMA Maximum allowable pressure

TMA Maximum allowable temperature

Minimum allowable temperature

PMO Maximum operating pressure for saturated steam service

TMO Maximum operating temperature

Minimum operating temperature (Note: For lower operating temperatures consult Spirax Sarco.)

Ambient temperature limits

DPMX Maximum differential pressure

Designed for a maximum cold hydraulic test pressure of:

Note: With internals fitted, test pressure must not exceed DPMX

Maximum

Minimum

PTFE soft seal

Fast opening

Flow over seat

Flow under seat

Flow over seat

Flow under seat

Air or water

360°

Maximum pilot pressure

" BSP

1⁄4" BSP

1⁄4"BSP

Technical details

Leakage

Flow characteristic

Flow direction

Pilot media

Actuator rotation

Actuator type and size

PF51G-NC

PF51G-NO

PF51G-BD

Pilot connection

Type 1 = 45 mm diameter

Type 2 = 63 mm diameter

Type 3 = 90 mm diameter

Kvs values

Size

1⁄2"

3⁄4"

1"

11⁄4"

11⁄2"

2"

Kvs

4.5

For conversion:

Cv (UK) = Kv x 0.963

8

15.6

24.6

42

57

Cv (US) = Kv x 1.156

TI-P373-14 CH Issue 4

PF51G Bronze Piston Actuated On / Off Valves

Page 2 of 8

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