Control valves

Self-acting controls

4.5.43

Stea m

saturation

curve

NS and NSRA

Gunmetal

Self-acting Control Valves

TI-P049-01

CH Issue 6

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© Copyright 2011

Description

The NS range of two-port valve are used in conjunction with

Spirax Sarco SA control systems to provide a self-acting temperature

control unit. Alternatively, they can be used as electrically actuated

temperature control valves by fitting an EL7200 Series electric

actuator with a suitable temperature transmitter and controller.

Available types:

NS

Normally open, double seat

NSRA Normally closed, double seat

Sizes and pipe connections

21⁄2" and 3" screwed BSP (BS 21 parallel) (NPT to special order).

DN65 and DN80 flanged EN 1092 PN25 (ASME / ANSI 150 and BS 10

Table 'H', which meets the requirements of Table F, to special order).

Pressure/temperature limits

NS

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Pressure bar g

The product must not be used in this region.

A Spirax Sarco spacer is required for use in this region.

(see TI-P033-01 for further details).

Body design conditions

Maximum design pressure

Maximum design temperature

Minimum design temperature

Maximum operating pressure for saturated steam service 17.5 bar g

PN25

25 bar g @ 120°C

260°C

-200°C

NSRA

Maximum operating

With spacer

temperature

Without spacer

Minimum operating temperature

Note: For lower operating temperatures consult Spirax Sarco

260°C @ 10.5 bar g

232°C @ 15.5 bar g

10.0 bar

10.0 bar

-10°C

Maximum differential pressure

Note: As supplied the test pressure must not exceed 25 bar g

NS

DN65 - 21⁄2"

DN80 - 3"

NSRA

DN65 - 21⁄2"

DN80 - 3"

2.7 bar

2.0 bar

Designed for a maximum cold hydraulic test pressure of 38 bar g

Materials

No. Part

1

Body

2

Body gasket

3

Valve closure member

4

Plunger

5

Plunger guide

6

Return spring

7

Spring housing

8

Bonnet

9

Stem

10

Body studs

Body nuts

Material

Gunmetal

BS 1400 LG2

Semi-ridged graphite BS 2815 Gr. A

Gunmetal

Brass

Brass

Stainless steel

Gunmetal

Gunmetal

Brass

Steel

Steel

BS 1400 LG2

BS 2874 CZ 121

BS 2874 CZ 121

BS 2056 302 S 26

BS 1400 LG 2

BS 1400 LG 2

BS 2874 CZ 121

BS 4439 Gr. 8.8

BS 3692 Gr. 8

Local regulations may restrict the use of this product to below the conditions quoted.

In the interests of development and improvement of the product, we reserve the right to change the specification without notice.

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