Cashco 1088 - Tank Blanketing - Manual (Page 2)

2 IOM-1088
the gauge.) This port is an optional horizontal outlet for
remote sensing valve type.
NOTE: The sense chamber is not a dead-ended cham-
ber. In addition to the fl ow when the valve is open, there
is also a very small fl ow from the valve into the ves-
sel through the sense connection. Therefore the sense
tube must be large enough so that the fl ow will not be
restricted. Premature closing of the valve may occur if
excess pressure builds up in the sense chamber due to
a sense line that is too small.
SECTION IV
IV. START-UP
Operation of the Model 1088 is automatic once the set
pressure has been set. (The set pressure is usually
bench-set at the factory prior to shipment.) NOTE:
The set pressure is defi ned as the pressure at which
the valve should be fully closed on increasing tank
pressure.
Refer to applicable drawing dependent on sensing style.
Temporarily keep valve A closed. Use an appropriate
pressure indicating instrument for G2 to measure the
pressure in the vessel.
For external sensing open valves C and E, then valve
B. For internal sensing open valve B. For integral dip-
tube proceed to the next step.
Now very slowly open valve A while watching gauge
G2. NEVER SLAM OPEN VALVE A! The Vacu-Gard
should close when the tank pressure reaches the set
CAUTION
If the valve must be disassembled for any reason, fi rst
make sure all pressure to the valve is blocked and
pressure trapped in the valve is vented safely. Refer to
your company procedure for any special precautions
when handling toxic or other hazardous materials.
CAUTION
A pressure/vacuum relieving device large enough to
vent excess pressure and to serve as an emergency
vacuum breaker must be installed to protect the tank.
CAUTION
DO NOT overtighten threaded connections since dam-
age or breakage may result. Use tefl on tape and/or
anti-seize compound on pipe thread joints.
CAUTION
DO NOT exceed the maximum inlet pressure on the
nameplate.
pressure. To adjust the set pressure, remove the hex
cap at the top of the valve and loosen the jam nut
around the adjusting screw. Clockwise rotation of the
adjusting screw will increase the set pressure. Counter
clockwise will decrease the pressure provided there is
a manual valve to vent the excess pressure. Do not set
the set pressure beyond the nameplate range. Tighten
the jam nut after adjustments are made and replace
the hex cap.
In the event that the adjusting screw is backed off without
compressing the spring, intentionally or unintentionally,
the valve will begin to open when the tank pressure
reaches about 1” w.c. vacuum.
SECTION V
V. SHUT-DOWN
To shutdown the Vacu-Gard, reverse start-up procedure and bleed off trapped pressure before disassembly.
SECTION VI
VI. MAINTENANCE
The Model 1088 should be periodically actuated and
all sliding surfaces and seals lubricated to ensure
smoothness of operation. The frequency required
depends on the severity of the service conditions. At
least once a year is recommended.