Taylor-Wharton EF-1000 - Manual (Page 11)

BT-472 Rev. B
11
The switch should be set to close at pressure below 125 psi and open after a predetermined pressure rise. To check the
setting, vent the container from a pressure greater than 125 psi where the HEATER lamp is off indicating the switch is
open and the heater is not receiving power. As the container vents, observe the container pressure gauge. At
approximately 125 psi the switch should close and the HEATER lamp will light. Close the vent at this point and allow
the heater to cycle until the pressure rises and the HEATER lamp goes out. Note the pressure rise on the pressure gauge
as well as the time interval between ‘heater on’ and ‘heater off’.
Warning:
The pressure switch/control box contains live 120VAC or 240VAC connections. Always disconnect the power
from the wall receptacle before removing the cover from this box for adjustment or maintenance.
If adjustment is needed, unplug the unit and unscrew four Phillips-head screws on top of the pressure control box. The
clockwise movement of the adjusting screw will raise the ‘heater on’ setting; counterclockwise will lower it. The
amount of pressure rise (or the heater ‘off’ setting) will adjust automatically. Move the set point adjustment a small
increment in the desired direction and repeat the venting procedure to determine the new set point. Repeat the process
as necessary until the set point is 125 psi.
Figure 4B: Pressure Switch Adjustment Screw
Gas Withdrawal Circuit
The gas withdrawal circuit vaporizes cryogenic liquid and warms it to ambient temperature for use in the final
application. Opening the gas withdrawal valve (V-3) allows liquid, driven by the pressure within the vessel, to flow
through the vaporizer (VC-1). The vaporizer uses heat from the ambient air to convert the liquid into a gas and warm it.
The vaporizer, like the pressure building coil, is attached to the inside surface of the vacuum jacket. The vaporizer is
located in the upper ¾ of the jacket, the pressure builder in the lower ¼.
Figure 5: Gas withdrawal circuit highlighted in blue.
CN-4
V-3
adjustment screw