Y692VB Series
3
INLET PRESSURE
CONTROL PRESSURE (VACUUM)
ATMOSPHERIC PRESSURE
Type Y692VB
B2579
VACUUM
BEING LIMITED
VACUUM
PUMP
indicated by the arrow cast on the body. If
continuous operation is required during inspection
or maintenance, install a three-valve bypass around
the equipment.
!
WARNING
This equipment may vent some gas
to the atmosphere. In hazardous or
flammable gas service, vented gas may
accumulate and cause personal injury,
death, or property damage due to fire or
explosion. Vent equipment in hazardous
gas service to a remote, safe location
away from air intakes or any hazardous
area. The vent line or stack opening
must be protected against condensation
or clogging.
Principle of Operation
An increase in vacuum (decrease in absolute
pressure) beyond the setpoint registers on the
diaphragm, opening the disk. This permits body
inlet pressure to enter the system and restore the
controlled vacuum to the setpoint. On Type Y692VB,
the pressure at the regulator body outlet registers
directly into the diaphragm casing. Type Y692VBM
has a control line connecting the diaphragm casing
to the vacuum being controlled and an O-ring stem
seal blocking the throat allowing for registration
only through the control line connection (outlet body
pressure may or may not be the same as the pressure
in the diaphragm casing).
Startup and Adjustment
All Y692VB Series vacuum breakers can be placed
in operation by slowly introducing inlet pressure.
The unit takes control when vacuum is established.
This equipment is suitable for the vacuum control
pressure range stamped on the nameplate (key 50,
Figure 5). To adjust the pressure setting, remove
the closing cap (key 3) and turn the adjusting nut
(key 2) clockwise to increase the pressure setting or
counterclockwise to decrease the setting. Replace
the closing cap after adjustment. The closing cap
may be wired to the hole provided in the spring case
(key 23) to discourage tampering.
Shutdown
To shut down the unit, close the upstream shut-off
valve, and then close the downstream shut-off valve to
vent the equipment properly. Next, open the vent valve
Figure 2. Operational Schematic
INLET PRESSURE
CONTROL PRESSURE (VACUUM)
ATMOSPHERIC PRESSURE
POSITIVE PRESSURE, ATMOSPHERE,
OR A LESSER VACUUM THAN THE
VACUUM BEING LIMITED
UNION NUT
TYPE Y692VB
VACUUM BREAKER
INLET PRESSURE
CONTROL PRESSURE (VACUUM)
ATMOSPHERIC PRESSURE
Type Y692VB
B2579
VACUUM
BEING LIMITED
VACUUM
PUMP
B2579
