5 Modular system
Operation manual mzr-2509 Ex/ mzr-2909 Ex / mzr-4609 Ex / mzr-7209 Ex
26
Technische Änderungen ohne Vorankündigung vorbehalten
Last update: October 2016
Functioning of fluidic seal module
Based on the pump design in the rotary shaft seal there is a liquid boundary
film where the liquid is in contact with the ambient. Here small amounts of
ambient humidity or oxygen can penetrate into the pump getting over the
sealing lip. To prevent penetrating molecules from outside into the pump but
also hazardous substances coming out of the pump the fluidic seal module was
designed.
For this reason a second rotary seal is added to the pump which is located in
the fluidic seal module. Between the two rotary seals a fluidic chamber (see
figure 15) is formed which is filled with a sealing liquid compatible to the
pumped liquid. The fluidic seal module has two ports opposite to each other
for filling and degassing. A pressure head can be applied to the sealing liquid to
assure a support of the sealing function. In certain cases the sealing can be
flushed.
The sealing liquid will dilute the pumping liquid during operation with a
dilution ratio of approx. 1:1,000,000. The sealing liquid has to be compatible
with the delivered liquid and has to be determined in interdependence. A
cartridge can be used as a reservoir and is sufficient at maximum flow for one
month in most cases.
fluidic chamber
figure 15
Sectional view of the micro annular gear pump with fluidic seal module
Operation with fluidic seal module
The selected
sealing liquid
has to be
compatible
with the
delivered liquid
. The
customer is in charge of the correct selection.
The filling procedure through the port has to be realized carefully. The ports
have a 1/4"-28 UNF thread. They are displaced to realize a better degassing of
the seal chamber also in a horizontal direction. The filling of the sealing liquid
starts with the lower level port. The filling of the fluidic seal module continues
until no bubbles can be seen on the outlet port side. When the liquid is free of