6 System integration
Operating manual mzr-2521 and mzr-2921
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Technical data subject to change without prior notice!
Last update: June 2019
Warning
Prolonged dry operation of the micro annular gear pump may damage in
particular the bearing and the sealing. However, a short dry working phase at
the beginning of the operation is harmless.
6.4
Filter selection and use
In majority of cases it is recommended to integrate a filter on the suction side of
the micro annular gear pump to ensure its secure operation. The recommended
filter pore or mesh size should not exceed 10 µm. The penetration of particles or
swarf that could cause a blockage or damage to the pump can only be avoided
by using an adapted filter.
HNP Mikrosysteme offers a choice of standard filters covering a broad spectrum
of applications. You may count on our assistance for the selection of the most
suitable filter.
In order to select the best adapted filter, such operating parameters as the flow
rate, the viscosity and the degree of pollution of the liquid will be needed. An
increase in at least one of the mentioned terms will require the use of a bigger
filtering element or pressurization of the delivered liquid. In case no suitable filter
for the given high-viscosity liquid can be found, it is possible to use a filter with
slightly larger pore size. Prior discussion with HNP Mikrosysteme is here
recommended. A filter with larger pores is still better than no filter at all. As an
alternative solution an already filtered liquid may be used.
Warning
Because filters have a large internal volume, it is recommended to fill in the
filter and the induction (suction) tubing with already filtered liquid in order to
avoid a too long dry run of the pump during the first operation.
Warning
Please control regularly the filtering elements for pollution. Cleanse regularly
the filter or replace it with a new one. A polluted filter may considerably
decrease the volumetric efficiency of a pump. Furthermore, because of the
cavitation effects dosage imprecision and even pump damage may occur.
Warning
A too small filter (too little filtering surface) may considerably decrease the
volumetric efficiency of the micro annular gear pump. What is more, because
of the cavitation effects dosage imprecision and even pump damage may
occur.
