Val-Matic 2-42 Flanged Vacuum Breaker - Manual (Page 2)

1
2 to 42 in. FLANGED VACUUM BREAKER
OPERATION, MAINTENANCE AND INSTALLATION
INTRODUCTION
This manual will provide you with the information to
properly install and maintain the vacuum breaker to
ensure a long service life. The vacuum breaker is
ruggedly constructed with bronze or stainless steel
trim to give years of trouble free operation. The
valve should be installed at high points along
horizontal pipelines or over tanks.
The Vacuum Breaker is designed to open fully and
allow air to re-enter the pipeline or system during
critical vacuum conditions in the pipe or tank caused
by power failure or rapid draining of the piping
system. The vacuum breaker will not allow air to
escape from the pipeline. An optional air release
valve can be piped to the side of the valve to release
trapped air during pipeline operation.
The size, cold working pressure, and model number
are stamped on the nameplate for reference. This
valve is not intended for fluids containing suspended
solids such as wastewater. For wastewater and
other high turbidity applications, use Val-Matic
Series 1800VBS Vacuum Breakers for Wastewater
Service.
RECEIVING AND STORAGE
Inspect valves upon receipt for damage in shipment.
Unload all valves carefully to the ground without
dropping. When lifting, the valve should be secured
by the body and never lifted by the bronze or
stainless steel trim.
The valves should remain crated, clean and dry until
installed to prevent weather related damage. For
long-term storage greater than six months, the
rubber surfaces of the seat should not be exposed to
sunlight or ozone for any extended period.
FIGURE 1. VACUUM BREAKER
DESCRIPTION OF OPERATION
The vacuum breaker is designed to prevent vacuum
conditions from occurring in pipes or tanks. After a
power failure or rapid draining of the system, a
vacuum condition often occurs in a pipe or tank.
The pressure difference between the inside vacuum
and outside air will cause a downward force on the
disc. At vacuum pressures greater than -0.25 psig,
the disc will compress the spring and move
downward allowing free flow of outside air into the
pipe or tank to eliminate the vacuum. When positive
pressure is restored in the pipe or tank, the valve will
automatically close and seal tightly. Optional valves
can be piped to the vacuum breaker to vent trapped
air in the pipeline if needed.
The valve may be supplied with either an optional
hooded outlet (not shown) or a flange for connection
to external piping or vent piping as shown in Figure
2. A flanged outlet is used when the valve vault is
subject to flooding or the vault cannot supply
sufficient air to the pipeline.
The only moving parts in the valve are the disc and
spring. The body bushing controls the movement of
the plug and assures that the plug contacts the seat
evenly. The valve has a resilient seal for drop tight
service.
CAUTION: This valve is not intended for
fluids containing suspended
solids or hazardous fluids.