3.30 Operating Pressure Range
3.31
Aspiration/Filtration Vacuum Systems are designed to be run from slightly below atmospheric to their
maximum vacuum level on the intake side. Consult the Specification Table for the ratings of
your specific model (See Section 6, Specifications).
3.40 Shutdown Procedures
3.41
After use, Welch recommends the pump be run for about 2 minutes disconnected from the vacuum
process. The air pumped through the mechanism will purge out water vapor or droplets of water
condensate that may have formed on the inside of the pump. This purge of the pump mechanism helps
prevent corrosion.
SECTION 4: MAINTENANCE
4.10 Maintenance Procedures
4.11
Maintaining a Welch Aspiration/Filtration Vacuum System
These units are 100% oil-free. The pump employs a non-lube piston and cylinder. No maintenance is
necessary for the bearings. All bearings are sealed and permanently lubricated. Lubrication should not
be attempted. The units are built for continuous duty operation with the quietness and durability of a
diaphragm, but with piston performance.
4.12
Hydrophobic Filter Replacement
Change the filter whenever foreign material is drawn into it or if you notice a reduction in vacuum level.
1.
Disconnect the long tube from the fitting on top of the jar lid.
2.
Gently pull the hydrophobic filter off of the short tube, that is connected to the
regulator inlet port, and then remove the long tube from the hydrophobic filter .
3.
With the green dot facing down, push the new hydrophobic filter into the short tube,
that is connected to the regulator inlet port, then push the long tube.
4.
Connect the long tube to the green dot facing barb, and then connect to the fitting
on top of the jar lid.
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