�C ______________________
Vacuum/Atmospheres
3-5 ESTABLISHING AN INERT ATMOSPHERE
If customer uses an evacuable vacuum glove box or VAC-LAB, evacuate
VAC-LAB, back fill with inert gas, then start regeneration (paragraph
3-5).
Install a valve in pressure sensing line of PEOA
TROL. Valve must be closed when VAC-LAB is evacu
ated, otherwise diaphram in PhotohelicCl) will rup
ture.
For ORI-LABS and other ambient pressure glove boxes having a PEOATROL,
the following procedure is suggested.
After instslling, electrical check (paragraph 3-2) and Leak Testing
(paragraph 3-3) of the entire ORI-LAB system, and after regeneration
(paragraph 3-4), perform the following steps:
A. Turn PEOATROL ON.
B. Set left indicator to approximately 5-inch positive and the
right indicator to approximately 4-inch positive.
C. Remove the plug from one of the service ports of the ORI-LAB.
O. This will cause continuous flow of gas from the reserve gas
supply. If the service port is large enough, the 20 psi
setting the reserve gas regulator will probably not hold more
than approximately 1-inch H2
o
positive pressure. The setting
may be raised up to 40 to 50 psi to speed the process, if
desired. Reset to 20 psi when through.
E. The regulator setting and the service port opening should be
such that the box pressure stays below 4-inch H2
o
positive,
but above 1-inch H2
o
positive.
(1) The Photohelic is a pressure sensing gage on the face of the PEOATROL.
(2) The SSG is the alternate s�nsing gage.
3-10
HE-493-Rl-7/90
