Composite PA6.6 pumps with threaded flat
sealings
Since 1989, Grundfos has been manufacturing and selling
pump housings and integrated hydraulic units of polymeric
composite, primarily PA6.6 with 30 % glass-fibre
reinforcement. When using composite, the optimal design
of connections is clip or hair-pin, because of their low
internal stress-generating level.
For threaded connections, the full thread length must be
used. The maximum assembly torque (e.g. 30 Nm ± 10) is
mentioned in the specifications of the pump. We
recommend to use EPDM gaskets.
For reason of overload risk, Grundfos does not
recommend to use composite threads for standalone
connections outside appliances.
All PA6.6 housings are defined as integrated. For
integrated pumps, the respective pump heads are tested
according to EN 16297/3 on a reference housing.
Expected lifetime of composite PA6.6
housings
The expected lifetime of composite PA6.6 housings in
heating applications depends on the liquid temperature
and the system pressure.
The liquid temperature must not exceed 95 °C.
For composite housings, Grundfos recommends that the
system pressure does not exceed 3 bar (0.3 MPa), for
cast-iron housings 6 bar (0.6 MPa). For shorter periods of
time, for example in fault scenarios, the composite
housing can withstand 6 bar (0.6 MPa).
The expected lifetime also depends on the time/
temperature profile of the application, based on which an
equivalent constant liquid temperature can be calculated.
The influence of the liquid temperature between 60 °C
and 95 °C on the expected lifetime is shown in the
following diagram.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
60 65 70 75 80 85 90 95
TM064413
Diagram temperature/expected lifetime for PA 6.6 30 %
GF
X-axis Constant liquid temperature [°C]
Y-axis Expected lifetime factor
Related information
Liquid temperature
UPM3
9
42
Technical description
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