Cla-Val 38VB/AR Series - Manual

SERIES
INSTALLATION / OPERATION / MAINTENANCE
38VB
Vacuum Breaker W/Optional Air Release Valve For Water and Sewage
1/2” - 3” Threaded 4” - 10” Flange Style
INTRODUCTION
Cla-Val Vacuum Breaker Valves are designed to perform years of
trouble free operation and service life. The valve functions to open,
allowing air to enter a pipeline, tank or system to prevent vacuum
forming. Sizes 1/2” thru 3” have threaded inlet and outlet, 4” and
larger have a flanged inlet as standard and a threaded, flanged or
plain outlet covered by a steel hood.
Standard Vacuum Break valves
have an internal spring with a fixed
rate to open between 1/4 - 1/2 PSI.
See fig 1. and Fig 1A For Vacuum
Breaker adjustability, external
spring with adjusting nut is sup-
plied see Fig.3. For Sewage, a
clear flow area body with external
spring and flushing valves is sup-
plied. see fig.4
Vacuum Breaker Valves in 2 Style:
HOW THEY WORK
The vacuum breaker valve (large ori-
fice combined with Air Release (small
orifice) are both normally closed but
when installed at points where vacuum
can occur. they work as follows:
The large orifice valve will open under
vacuum, allowing air into pipeline to fill
the void, created by vacuum. Next it
instantly closes trapping air, that is
compressed, there by cushioning
return of positive fluid pressure, to pre-
vent severe pressure surge and water
hammer,
Optionally the small orifice Air Release
Valve will also open, due to vacuum
and stays open acting as the outlet, to
slowly release the trapped air, from the
system until normal pressure is
achieved at which point the small
orifice closes.
RECEIVING AND STORAGE
Immediately inspect shipment upon receipt for damage in transit and
report same to carrier.
Store valves in a dry area until ready to install to prevent damage
when storing longer than six months coat rubber seat with FDA
approval grease to preserve resiliency.
Fig.4
Optional
Air Release
Valve
SMALL
ORIFICE
AIR RELEASE
OPEN
CLOSED
VACUUM
BREAKER
LARGE
ORIFICE
AIR
OUT
AIR
IN
Large
Orifice
Fig 1A
AIR RELEASE
small
orifice
VACUUM
BREAKER
LARGER
ORIFICE
For Sewage
Fig. 4
STANDARD
ADJUSTABLE
Valve Shown in
Open Position