ProMinent mikro g/5a Instruction Manual page 11

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ProMinent mikro g/5a
Precision feeding pump
Parts subject to wear
In spite of carefully choosing materials and the optimum design of the seals they can
possibly become defective. The plunger V packings are prestressed with disc
springs from the side turned away from the medium so that an automatic adjustment
of the V packing takes place until it is finally worn down. Under certain circumstances
the V packing can also become untight if this has not yet worn down. It can for
example take place due to deposits from carbon abrasion from the V packing onto
the plunger, e.g. during prolonged metering with water with high surface tension.
When the metering plunger sealing is not tight the leaking medium drops out of the
mounting flange between the liquid head and housing.
Remedy:
a) Let the metering pump feed dichloromethane or acetone, the impurity then sorts
itself out, the plunger sealing is once again intact.
b) If this is not successful the V packing is worn out and must be replaced by a new
one.
c) Trouble shooting
If there is no flow from the metering pump due to an unknown reason the nearest
disturbance source is first to be tracked down. Switch on the pump, set maximum
stroke length and stroke frequency, push the sliding lock of the liquid end to the front.
If a stroke movement takes place, the fault must be sought in the liquid end. Loosen
the bleed screw on the back-pressure valve. If this is unsuccessful the valve must
be rinsed with the appropriate media as described above. If there is no stroke
movement at the plunger the electronic circuit is probably faulty. In this case change
the fuse, if necessary the control must be changed at the factory or on location.
Instruction manual
mikro g/5a
Page 11