Cla-Val 750B-4KG - Manual (Page 5)

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INLET OUTLET
750B-4KG1 Basic Components
Fire Protection Pressure Relief Valve
750B-4KG1
Description
The Cla-Val Model 750B-4KG1 Pressure Relief Valve is a hydraulically
operated pilot actuated automatic control valve designed specifically to
automatically relieve excess pressure in fire protection pumping systems.
Pilot controlled, it maintains constant system pressure at the
pump discharge within very close limits as demands change. The main
valve consists of a stainless steel body and only one moving part, an
elastomeric liner or control element.
Cla-Val Model 750B-4KG1 will control from no flow, to full open flow, with-
out any chattering or slamming. For this reason, there is never a region
of control instability. There is no slip-type friction because the valve has
no bearings. Cla-Val Model 750B-4KG1 valves have excellent resist-
ance to cavitation with a Cf factor of 0.9.
Pilot controls are fully piped at the factory and the Cla-Val Model 750B-4KG1
is shipped complete, ready for installation.
Material Specification
Body: 316L Stainless Steel
Liner: Nitrile, 70 durometer
Liner Retainer: 316 Stainless Steel
Pilot
Body: ASTM B62 Bronze *
Spring Cover: ASTM B62 Bronze *
Wetted Parts: Bronze/Stainless Steel *
Buna-N ®
Accessories
Check Control: Brass *
Control Piping: Copper *
“Y” Strainer: Bronze *
Control Fittings: Brass *
* 316 stainless steel available
Item Description
1 100-42 Roll Seal Main Valve
2 CRL5A Pressure Relief Control
3 X58A Restriction
4 81-01 Check Valve (125 psid max. reverse pressure)
5 X43 Y-Strainer
6 Pressure Gauge
FM
PENDING
At pump start, the Cla-Val Pressure Relief Valve modulates
to relieve excess pump capacity, maintaining positive sys-
tem pressure at the pump discharge.
When fire demand slows or ceases, the main valve opens,
diverting the entire pump output to discharge, allowing the
fire pump to be stopped without causing surging in the lines.
(Please note that when the Model 750B-4KG1 is to be used
on a continuous duty basis to maintain fire-system pressure,
suitable back pressure must be provided on the valve to pre-
vent cavitation damage. Consult the factory for details.)
Operation Sequence
MODEL
For Seawater Service Options See 750-20 E-sheet
For other than standard ANSI flanges consult factory
Din drilling available on all sizes