MB2000/3000/5000 OPERATING AND MAINTENANCE MANUAL
TAYLOR-WHARTON (BEIJING) CRYOGENIC EQUIPMENT CO., LTD.
17
PCV2,the iLI1et pipe of atmospheric vaporizer become clod that means the valve is
opened
。
INNER VESSEL AND PIPING SAFETY DEVICES
These tanks are equipped with a dual safety device manifold that permits servicing of one set of safety
devices while the other set is in service.
If a pressure vessel tank rupture disc ruptures, determine and correct the cause of the rupture before
replacing the device. This device should be replaced annually as a preventive maintenance procedure. The
bursting disc on this tank is a sealed assembly that must be replaced as a unit.
Main tank pressure relief valves that leak or fail to operate at the set pressure should be replaced
immediately. Repair and recalibration of these valves should oLI1y be done by experienced personnel
with proper equipment. Return the valves to the manufacturer or to an ASME approved repair station for
overhaul or recalibration. In certain cases these valves shall be tested every five years per CGA S-1.3,
section 9, “Pressure Relief Device Standards Part 3 – Stationary Storage Containers For Compressed
Gases”.
Replace thermal expansion relief valves when leakage or improper functioning occurs. Do not attempt to
repair or reseat these components since they are of the throw-away type
。
PRESSURE AND LIQUID LEVEL GAUGES
The major cause of malfunctioning tank pressure gauge, inner vessel, or liquid level gauge is an open
equalization valve or leakage in the gauge lines. Refer to the Trouble-Remedy Guide in this manual for
maintenance procedure. If the problem is not readily corrected, replace the gauge with a spare. Return the
defective gauge to the manufacturer for repair.
Include a description of the difficulty encountered.
CASING VACUUM MAINTENANCE
CHECKING VACUUM
Some vacuum deterioration may occur over an extended period of time due to out gassing of materials
within the vacuum space or from leakage. A history of vacuum readings taken over a period of time can
be valuable when evaluating tank performance and scheduling maintenance work.
To detect vacuum deterioration, periodic measurement of the tank vacuum is recommended. A
thermocouple-type vacuum probe, located on the lower head of the tank, is provided for this puPCV1ose
To check tank vacuum perform the following steps:
1
Remove the protective plastic cap from the gauge tube connector.
2
Connect a Hastings-Raydist Model No. TV-4A or VT-6 Vacuum Gauge to the vacuum probe.
3
Open the vacuum probe isolation valve and wait at least 60 minutes before taking the vacuum
reading.
4
After the vacuum reading is recorded, close the vacuum probe isolation valve, disconnect the
Vacuum Gauge, and replace the protective cover on the vacuum probe connector.
The vacuum reading obtained on a cold tank is initially less than 50 microns (0.05 mm Hg) absolute;
