MB2000/3000/5000 OPERATING AND MAINTENANCE MANUAL
TAYLOR-WHARTON (BEIJING) CRYOGENIC EQUIPMENT CO., LTD.
15
MAINTENANCE
GENERAL
The need for maintenance usually becomes apparent from inspection of the tank before filling, routine
observation during and after filling, and indications of improper operation. Typical trouble indications
would be unusually high or low tank or pipeline pressure, leakage from valves or piping connections, and
excessive venting through relief valves. Prompt action to correct damage or malfunction is required to
assure reliable operation. Keep a permanent log of all inspections, vacuum readings, and repairs
performed. Such a log can be valuable in evaluating tank performance and scheduling maintenance.
Always observe the safety precautions at the front of this manual and follow the instructions given in this
section. Before working on the tank or piping system, isolate the piping section to be repaired from the
tank, and relieve pressure on the component or piping.
Do not allow unqualified persons to attempt repairs on this equipment. Field repairs to instruments and
controls must be made by a qualified instrument specialist. Refer to the Trouble-Remedy Guide in this
manual for assistance in troubleshooting.
Make certain all parts that will come in contact with cryogenic liquid or gaseous product have been
cleaned for in conformance with CGA Pamphlet G-4.1, "Cleaning Equipment for Oxygen Service", or
other equivalent standard. If parts are purchased cleaned for oxygen service, they should be suitably
packaged to prevent contamination
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LEAK TESTING
After making repairs requiring disassembly or part replacement, leak test all valves or piping joints that
were taken apart and reconnected. Apply the leak detector to the test surface per the manufacturer's
instructions. Large leaks instantly form large bubble clusters, while fine leaks produce white foam that
builds up more slowly. All leaks must be repaired and retested before the tank is returned to service.
WARNING: For O
2
System Users: Residue of leak detectors can be flammable. All surfaces
to which the leak detector solutions have been applied must be adequately
rinsed with potable water to remove all traces of residue. Reference CGA G
4.1. Section 5.
HAND VALVES
The most common trouble with manual valves will be leakage at the stem packing. Packing leaks are
usually indicated by frost or ice accumulation more than half way up the valve stem extension. If packing
leakage cannot be stopped by tightening, add or replace packing. Use preformed packing, which can be
ordered from the valve manufacturer.
CONTROL VALVES
These tanks have three automatic valves that control operating pressures, PCV1 and PCV2 and PCV3 .
the pressure building regulator PCV1 opens on falling tank pressure and closes on rising pressure. This
valve is factory set at 1.2MPa for M series tank and 3.0MPa for V series tank.
