Table of Contents
Advertisement
CROSBY STYLE JQ 4 IN. PRESSURE RELIEF VALVE
INSTALLATION AND MAINTENANCE INSTRUCTIONS
10.3 Reassembly of the Breaking Pin Assembly
CAUTION
Failure to follow these instructions may result in
improper function of the valve.
Always wear proper PPE.
10.3.1 Install Breaking Pin (31)
Insert the Breaking Pin (31) into the Yoke (30)
and fasten the upper Clip (34). Be careful to
avoid any side strain on the notched portion
of the Breaking Pin (31) when handling or
assembling. Then, insert the lower half of
the Breaking Pin (31) into the Housing (35)
and fasten the lower Clip (34). Be sure to use
the proper Breaking Pin (31) and Clips (34)
(Section 6).
10.3.2 Insert Lower Diaphragm (37)
Carefully insert the new Lower Diaphragm (37)
into the Housing (35). The diaphragm must lay
flat on the serrated surface and not ride up
on the side of the Housing (35). No lubrication
is allowed between the diaphragm and the
serrated Housing (35) surface.
10.3.3 Install Follower (36)
Lightly lubricate both sides of the
Follower (36) (6.2.3). Place the Follower (36) into
the Housing (35) with the smooth side down
against the Lower Diaphragm (37).
10.3.4 Install Spanner Nut (33) and Vacuum Grill (38)
Lightly lubricate the threads of the Spanner
Nut (33), the curved interface surface and the
threads on the Housing (35) (6.2.3).
Insert the Vacuum Grill (38) with the notches
resting on the Follower (36) and centered.
Thread the Spanner Nut (33) into the
Housing (35). The Spanner Nut (33) must
turn freely by hand pressure only until
the Follower (36) contacts the Lower
Diaphragm (37). Tighten the Spanner Nut (33)
using the Spanner Nut Driver (48) and Holding
Fixture (49). The Spanner Nut (33) must be very
tight to compress lead into the sealing grooves.
No wrinkling of the Lower Diaphragm (37) is
permitted during this assembly. The Vacuum
Grill (38) should not be tight against the Lower
Diaphragm (37).
10.4 Test the Lower Diaphragm (37) for Leaks
WARNING
Failure to follow these instructions can cause
damage to the valve and potentially personal injury
from an over pressure event.
A person should NEVER stand directly over or in
front of or look directly into a relief valve when the
tank or test stand is pressurized. The relief valve
could suddenly "pop" open blowing gas, dirt and
other debris into the person's face and eyes.
The Lower Diaphragm (37) must be absolutely
gas tight. This test is very important because if
gas leakage should occur, pressure will build
up in the Breaking Pin Housing (35) increasing
the pressure at which the Breaking Pin (31)
will fracture.
Place the Gasket (44) and the breaking pin
assembly on the Adapter Flange (40). Then,
bolt the Test Bonnet (47) with bubble counter
device to the Adapter Flange (40) using a Safety
Mechanism Gasket (16).
• Bubble Cap Tester Method
Fill the cup of the bubble counter until the
tube opening is 0.5 in. below the surface of the
water. Using helium, gradually apply pressure
to 300 psig for the 375 psig Breaking Pin (31)
or 240 psig for the 300 psig Breaking Pin (31).
After the pressure is reached, observe the
bubble counter for three minutes. There
should be no bubbles observed during this
period. Any leakage is cause for rework
and retest.
• Electronic Leak Tester Method
Secure the breaking pin assembly to the test
plate. Apply 5 psig helium pressure to the test
assembly, followed by air pressure to
300 psig for the 375 Breaking Pin (31) or
240 psig for the 300 Breaking Pin (31). Using
an electronic leak tester with the probe
inserted near the Lower Diaphragm (37)
or hole in Test Bonnet (47), check for any
leakage. Any leakage is cause for rework
and retest.
13
Advertisement
Table of Contents
