Troubleshooting
6-4
E 1999 Nordson Corporation
All rights reserved
104 330H
Issued 8/99
Manual 1-8
The following information is given as an aid to solving pump problems.
Use the following guidelines to minimize pressure deviations in the 25B
pump.
Air Supply
Correct sizing and installation of the pump air supply system will reduce
pressure deviation problems. One indication of an inadequate air supply
is excessive needle deflections on the incoming air line gauge as the
pump strokes 0.35 bar (5 psi) or less is normal. Fluctuations above 0.35
bar (5 psi) indicate a restricted air supply.
If it is inconvenient or expensive to install a larger air supply line, an air
accumulator can be installed at the pump. This will minimize the air line
pressure drop that occurs when the pump reverses at the end of each
stroke and ensure an adequate air volume during pump changeover.
Air Exhaust
Restricted exhaust air can have the same effect as a restricted air supply.
The restriction can be caused by ice build-up, wrong size or design of
mufflers, or contamination. Icing can be caused by high cycle rates at
high air pressures, by moisture laden supply air, or by restricted mufflers.
If the pump needs to be operated at high cycle rates and air pressures to
maintain the desired fluid pressure and flow rate, a larger pump may be
needed. The air supply must be clean and dry. Use of a refrigerated air
drier and air filter/separators is recommended. Another way to reduce
ice build-up and exhaust noise is to exhaust the air into a large common
pipe manifold fabricated from 3- to 4-inch PVC pipe.
3. General Pump
Information
Minimizing Pressure
Deviations
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