Varian 979 Series, Руководство по эксплуатации

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Model 979 Series Helium Mass Spectrometer Leak Detector
1-10
DRAFT 9/15/03
1.3.2 Helium
For testing products, or leak checking the 979, welding grade helium in a standard cylinder
with pressure regulating valve and hose is required.
1.3.3 Recommended Additional Services
The following additional services are recommended, especially in the case of clean room
use:
❑
A roughing/foreline pump exhaust hose to the outside of the room using the
connection on pump exhausts. This can help reduce the particulate count and the
helium background signal.
❑
When using oil lubricated mechanical pumps, an oil mist eliminator can be used on
the exhaust port of the mechanical pump to reduce the oil mist from the exhaust. Oil
mist eliminators can, however, become saturated with oil causing slower pumping
speeds and higher helium backgrounds in the leak detector. The replacement time
interval of the oil mist eliminator is determined by whether the user frequently
operates at elevated roughing pressures, pumps on large volumes, or frequently
cycles the system. Refer to Section 4.6 “979 Spare Parts List” on page 4-22 and
Section 4.7 “979 Accessory Item List” on page 4-24 for the mist eliminator and
replacement cartridge part number.
1.4 Preparation for Operation
Pre-operational set up is minimal for the 979 Series leak detector.
Oil sealed vacuum pumps are shipped with the proper initial charge of oil. On the front of
the roughing and forepumps is an oil level sight glass. The oil level should be in the middle
of the glass when the pump is not running. Check the oil level after running the pump for at
least 10 minutes. For additional information, see the
Mechanical Pump Operation Manual
that was enclosed with your pump.