Labconco Precise Controlled Atmosphere and Basic Glove Boxes 5220131 - Manual (Page 57)

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A A p p p p e e n n d d i i x x G G : :
H H e e l l i i u u m m L L e e a a k k T T e e s s t t P P r r o o c c e e d d u u r r e e
Purpose
The purpose of this test is to assure that all gasketed joints and seams of the
enclosure are helium leak tight.
Test Setup
1. Connect one of the valves to a vacuum pump.
2. Connect the other valve to a helium supply tank regulated between 10
and 15 PSI.
3. Install two neoprene gloves onto the glove ports using standard O-
rings and clamps.
4. For testing the Precise Basic Glove Box, a test fixture attaches to one
of the glove ports and replaces one of the gloves.
Test Procedure
1. Be sure the inner transfer chamber door is latched closed and the
outer door is open.
2. Open the helium inlet test valve and allow box to pressurize to +5
H
2
O gauge than close valve. Then with the vacuum pump running,
open the test outlet valve and allow the box to be evacuated to -5"
H
2
O gauge then close valve. Repeat this purge/fill for a total of three
cycles then close both valves.
3. While Glove Box pressure is held at +5.0" minimum, sniff all Glove
Box joints, seals and seams of the Glove Box shell using a test probe
connected to a helium mass spectrometer (Inficon model or equal
calibrated at 1.7 x 10
-7 STD. CC/SEC). Also sniff the inner transfer
door seal by inserting test probe through the outer transfer chamber
door. Any detectable leaks greater than 1 x 10
-4 STD.CC/SEC is
cause for rejection. Pressure relief valve is measured 1/2" away.
4. Close and latch the outer door and open the inner door. Adjust Glove
Box pressure to +5.0".
5. Sniff the outer transfer door seal and make sure there are no leaks
greater than rate specified in Step 3 above.