UK Product Handbook 2026 - Volume 1

Control systems Self-acting controls

4

Pressure/temperature limits

Pressure psi g

0

72.5

145

217

290

362

500 449 392 302 212 122 32

Steam saturation curve

Pressure bar g

The product must not be used in this region. When the valve is operated with a self-acting temperature control system in this region, a Spirax Sarco spacer must be used.

Body design conditions

PN25

Fitted to a Spirax Sarco spacer

260 °C

500 °F

Maximum design temperature

Fitted directly to an actuator

232 °C

450 °F

4.5 23

BX

17.2 bar

250 psi

Maximum differential pressure

BXRA

10.3 bar

150 psi

Designed for a maximum cold hydraulic test pressure of:

38 bar g

550 psi g

Kv values BX2

BX3

BX4

BX6

BXRA

For conversion: Cv (UK) = Kv x 0.963 Cv (US) = Kv x 1.156

0.38

0.64

1.03

1.65

0.59

Capacities For saturated steam sizing capacities, see TI-GCM-08. For water sizing capacities, see TI-GCM-09.

TI-P036-02 CTLS Issue 7

Page 3 of 5

BX and BXRA Gunmetal Self-acting Control Valves

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