Spirax Sarco SRV2S - General Installation; Safety Valve

IM-P186-03 CH Issue 4
8
3. Installation
A Steam trap
B Strainer
C Isolating valve
D Safety valve
E Pressure gauge
F Separator
3.1 General installation
Always install the SRV2S with the flow direction arrow (on the body) pointing downstream.
The
SRV2S pressure reducing valve is available as follows:
Screwed
½", ¾" and 1" BSP (BS 21 Rp) or
Flanged
DN15, DN20 and DN25 EN 1092 PN25 and ANSI 150.
The
Spirax Sarco SRV2S pressure reducing valve should always be fitted in a horizontal
pipeline. The adjustment head may be above or below the valve.
Isolating
valves should be installed, upstream and downstream of the SRV2S, with a clear run
of
8 to 10 pipe diameters on either side.
It
is important that line stresses, caused by expansion or inadequate pipe support, are not
imposed
on the valve body.
Upstream
and downstream piping must be of ample size to avoid undue pressure drop.
Any
reduction in line size should be made using eccentric reducers.
Fitting
a strainer on the upstream side will give additional protection to the valve. Install the
strainer
on its side to prevent the body filling with water, which will reduce the effective
screening
area. If the steam supply is wet a separator/trap set should be installed upstream.
Alternatively,
an adequate drain pocket and a trap from the Spirax Sarco range should
be fitted.
A pressure gauge is essential on the downstream pipework to allow setting of the operating
pressure.
It is an advantage to have a gauge on the upstream side of the valve, as well.
Safety valve
A safety valve should be fitted to protect the downstream equipment from excessive pressure
(to
meet local standards). It should be set to lift below the safe working pressure of the
downstream
equipment, and will normally be sized to pass the full capacity of the SRV2S should
it fail in the fully open position. The safety valve set pressure should take account of its reseat
characteristic
and the 'No-load' pressure setting of the SRV2S. Discharge pipework should
be
taken to a safe place.
Note: Before actioning any installation observe the 'Safety information' in Section 1.
Note: If you experience difficulty with installation or operation of this equipment please contact:
Spirax-Sarco Limited, Charlton House, Cheltenham, Gloucestershire, GL53 8ER
Tel: +44 (0)1242 521361, Fax: +44 (0)1242 573342
Fig. 2 Recommended installation
C1
C2
C3
F
A
B
SRV2S
D
E2
E1