Welch Vacuum 2534 WOB-L Pinston Pump - Manual (Page 8)

Section 3: OPERATION
3.10 STARTING PROCEDURES
3.11 Starting A Welch Pressure/Vacuum Pump
Before attaching the pump to a system, familiarize yourself with the function and action of the
pressure/vacuum pump that you have acquired. Review the power requirements as described in
Section 2.60. Welch recommends running the pump for a few minutes to warm it up, before use.
The warm-up improves the pumps ability to handle humid air.
3.12 Cleanliness
Take every precaution to prevent foreign particulates from entering the pump. Particulates
will damage the pump’s performance. If you fi nd that particulates come off the process during
evacuation, a particulate trap in the foreline will work. A simple, inexpensive trap may be made
by placing glass wool in a glass or plastic tube. Screens must be inserted to hold the glass wool
in place.
3.20 LEAK DETECTION
The importance of eliminating all leaks in a vacuum system is obvious. The pump must remove
this added volume of leaked gas to maintain the desired vacuum. Leaks for these pump can
be located by slightly pressuring the system and painting the suspected area with a thick soap
solution. Escaping air will produce soap bubbles.
3.30 PRESSURE RANGE
Pressure/Vacuum pumps are designed to be run from slightly below atmospheric to their
maximum vacuum level on the intake side. The pumps also may be run from atmospheric
to their maximum rated pressure rating. Consult the Specifi cation Table (See Section 6,
Specifi cations) for the ratings of your specifi c model.
3.40 SHUTDOWN PROCEDURES
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 GENERAL MAINTENANCE
Welch dry pressure/vacuum 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.
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