Taylor-Wharton LP3 - Manual (Page 19)

9. When reinstalling the pressure building regulators on the system, orient the regulator so the flow
arrow points toward the pressure building valve.
Adjustment of the economizer regulator should be accomplished with the regulator removed from the system.
The regulator bench adjustment fixture shown above should be used.
1.
Leak test joints between the high pressure cylinder regulator and the dump valve. Joints must be
leak free before proceeding.
2.
Close the on/off valve. Open the dump valve.
3.
Open the high pressure cylinder valve.
4.
Set the high pressure regulator above the desired set point for the economizer.
5.
Slowly open the on/off valve for a few seconds and then close it.
6.
When the regulator under adjustment closes, the economizer set point is indicated on the
upstream pressure gauge.
7.
To reset the regulator, loosen the lock nut on the adjusting screw. Raise the setpoint by turning
the adjusting screw clockwise; lower the setpoint by turning the screw counterclockwise. After
adjustment, repeat steps 5 and 6 to check the setting before reinstalling the regulator on the liquid
container.
Instruments
User adjustment of the pressure gauge or liquid level gauge is not possible. If the gauges are malfunctioning,
they must be replaced. Empty the container of liquid and completely depressurize it before replacing either
gauge.
Note that the liquid level gauge may read erratically while the safety valve is venting. This is normal and will
stop when the safety valve reseats.
Checking Vacuum
Cryogenic containers are two containers, one within the other. The space between the containers acts as a
highly efficient thermal barrier including high technology insulation, a vacuum, and a vacuum maintenance
system. Each serves a very important part in the useful life of the container. The high technology insulation is
very effective in preventing radiated heat from entering the inner container. Unfortunately, the perfect
vacuum cannot be achieved since trace gas molecules begin to enter the vacuum space from the moment of
manufacture. The vacuum maintenance system consists of materials that gather trace gas molecules from the
vacuum space. The maintenance system can perform its function for years, however it has a limited capacity.
When the vacuum maintenance system becomes saturated it can no longer maintain the vacuum integrity of
the container. The change will be very gradual and may go unnoticed for several years. When the vacuum in
the insulation space is no longer effective, the following symptoms may appear:
1.
With liquid in the container, the outer casing will be much colder than comparative containers.
2.
Frost, indicating the liquid level, may be visible on the outer casing of the container.
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