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CROSBY STYLE JQ 4 IN. PRESSURE RELIEF VALVE
INSTALLATION AND MAINTENANCE INSTRUCTIONS
11 REASSEMBLY OF SAFETY VALVE PROPER
AND THE BREAKING PIN ASSEMBLY
11.1 Installation of the Breaking Pin Assembly
CAUTION
Failure to follow these instructions may result in
improper function of the valve.
Always wear proper PPE.
Check the safety valve proper and the breaking
pin assembly to be sure that both are rated
for service at 300 psig or 375 psig. Visually
inspect the threads and gasket surfaces of
both the Breaking Pin Housing (35) and the
Valve Base (17). If necessary, carefully clean
the threads and gasket sealing surfaces to
remove any foreign materials. Lubricate one
surface of a new Safety Mechanism Gasket (16)
and the threads of both the Breaking Pin
Housing (35) and Valve Base (17) (6.2.3). Screw
the breaking pin assembly into the safety valve
proper handtight using caution to assure proper
thread engagement. Holding the breaking pin
assembly on the flat surface, tighten the safety
valve proper onto the Housing (35) using a hook
shaped wrench or strap wrench. As a check
against tampering prior to valve installation,
insert a sealing wire through the handle on the
Cap (1) and then through the Lock Strip (21) in
the Base (17).
11.2 Paint
After testing, mask the surface of the Breaking
Pin Housing (35) and paint the exterior of the
valve if necessary.
CAUTION
Do not obliterate data plate.
11.3 Storage and Handling
Safety valves may be on location months before
they are installed. These valves should be stored
indoors in a location where dirt, moisture and
other forms of contamination are at a minimum.
It is best to leave safety valves stored in a dry
place with protected covering on the gasket
surface until they are to be installed.
Safety valves should be handled carefully.
Rough handling may damage the Lower
Diaphragm (37), gasket tongue, valve seats or
the breaking pin assembly.
12 SPECIAL MAINTENANCE PROCEDURES
12.1 Cleaning
CAUTION
Failure to follow these instructions may result in
improper function of the valve.
Always wear proper PPE.
Completely disassemble the safety valve proper
and the breaking pin assembly. Place parts in
a wire basket and clean by direct impingement
of steam on the parts. Alternatively, cleaning
parts in a pail with boiling water has been
successful. Some parts have also been cleaned
utilizing high pressure blasting with a water
and aluminum oxide mixture. Heavily coated
or corroded parts may require wire brushing,
steel grit blasting of steel parts and glass bead
blasting (or equivalent) of Monel parts. In all
cases, seating surfaces should be protected to
avoid damage. After cleaning, all parts should be
dried and carefully inspected for suitability for
continued use.
12.2 Converting from Metallic Seat to
Elastomeric Seat Design
The elastomeric seat valves are identical to
the metallic seat valves except as noted in
Table 6.1.A. Existing metallic seat valves may be
altered as follows:
• Disassemble the safety valve proper
per Section 8.2 and remove the Lock
Pin (12), Adjusting Ring (11), Nozzle (13)
and Nozzle Washer (14) from the
Base (17); install the new Nozzle (13),
O-ring (14), and the existing Adjusting
Ring (11) per Section 9. 3. Replace the
Disc Guide (7) per Section 9. 3.3, and
install the new Disc Assembly (10A-E)
per Section 9.3.4. Continue assembly per
Sections 9.3.6 and 9.5.1.
• Valves changed over to O-ring seat
design should carry identification
Type 4 JQ valve, Shop No. 86006 for
4 in. JQ 300 valve or Shop No. 86007 for
4 in. JQ 375.
14
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