Fluke Biomedical 940-513 - Manual (Page 14)

Operation
Installation and Set-up
3
3-2
NOTE:
The potential exists for radioactive gas to be present
within the sample volume. It is recommended that
this procedure be reviewed by the local plant Health
Physist
3.1.1.4 Gently push the detector forward, until the detector end cap stops against the internal
Gas Chamber Cap. The Gas Chamber Cap, P/N 940-513-11, is located on the opposite
end of the sampler, inside of the sampler and attached to the P/N 841A-123-5 Filter Plug
and Solenoid assembly, and defines the outer edge of the sample volume.
3.1.1.5 Tighten the six (6) detector flange mounting screws that were loosened in above.
3.1.1.6 Loosen and remove the six (6), 10-24 x 0.75 in socket head cap screws that retain the
adapter flange to the sampler body. Carefully remove the detector and mounting flange
assembly.
3.1.1.7 With the detector and mounting flanges removed, draw a line on the detector body,
adjacent to the detector mounting flange, on the side of the detector mounting flange
facing the connector end of the detector. This will indicate the position of the detector
when fully inserted.
3.1.1.8 Loosen the six (6), 10-32 x 0.5 in detector flange mounting screws, the screws that retain
the detector to the detector mounting flange.
3.1.1.9 If the detector has not been replaced for over 18 months, the detector mounting flange
should be removed, and the 46-103 Quad lobed seal should be inspected for wear or
damage. If the seal is worn, it should be replaced at this time. When replacing the seal,
the new seal should be lubricated with O-ring lubricant, Dow Corning #55, or equivalent,
and the detector mounting flange loosely re-installed
3.1.1.10 With the detector mounting flange mounting screws loosened, slide the detector
mounting flange forward, toward the sensitive end of the detector, until the distance
between the mark applied above and the detector mounting flange is 0.25 inches. Re-
tighten the six (6) detector mounting screws to lock the detector and mounting flange
assembly in position (i.e.with the detector withdrawn 0.25 inches from the Gas Chamber
cap, when re-installed, providing a sensitive volume of approximately 11cc’s).
3.1.1.11 Using the caliper, recheck the distance between the line marked on the detector body,
the fully inserted position, and the detector mounting flange. This distance must be 0.25
inches to ensure the efficiency obtained in the primary isotopic calibration will be realized
in operation.
3.1.1.12 If the detector has not been replaced for over 18 months, the 46-104 Quad lobed seal
that seals the adaptor mounting flange to the sampler body should be removed and
inspected for wear or damage. If the seal is worn, it should be replaced at this time.
When replacing the seal, the new seal should be lubricated with pneumatic grease, Dow
Corning #55, or equivalent, and the Quad lobed seal re-installed
3.1.1.13 Carefully re-insert the detector assembly into the sampler body.
3.1.1.14 Install and tighten the six (6), 10-24 x 0.75 in socket head cap screws and split lock
washers that retain the detector assembly to the sampler body.
3.1.1.15 Again, using the caliper, measure the distance from the cable end of the detector to the
rear face of the detector mounting flange. Record this distance on the Data Sheet
provided. This dimension may be used in the future to verify the installed detector
position.