Watson-Marlow 620U - Manual (Page 82)

Watson-Marlow 620UN, 620U, 620SN, 620S User Manual 82
26.3 620RE, 620RE4 and 620R
pumping conditions
Pressure and viscosity
All pressure values in this operating instruction, from which performance and
life figures have been calculated, relate to peak pipeline pressures.
Although rated to 4 bar peak pressure, this pump will generate in excess of 4
bar peak pressure if pipeline restrictions are in place. In instances where it is
critical that a peak pressure of 4 bar is not exceeded, pressure relief valves
should be installed in the pipeline.
For pumping duties of 2-4 bar pressure, fit hard Marprene/Bioprene or standard
Sta-Pure or Chem-Sure tube elements. “M” or “P” in the tube element’s product
order code denotes suitability for higher pressure use.
For pumping duties of 0-2 bar pressure, use standard hardness elements or the
standard range of continuous peristaltic pump tubing.
Viscosity handling is maximised by using hard Marprene/Bioprene or Sta-Pure
tube elements in the pumphead.
Ensure that there is always a minimum of one metre of smooth bore flexible
tubing connected to the discharge port of the pumphead. This will help
minimise any impulse losses and pulsation in the pipeline. This is especially
important with viscous fluids and rigid pipework.
26.4 620RE, 620RE4 and 620R
pump installation
A correctly engineered installation will promote the best possible tube life, so please
ensure that the following guidelines are followed:
Avoid tight pipeline bends, pipe reducers and excessive lengths of smaller bore
tubing than that in the pumphead, particularly in pipelines on the suction side.
Ensure that connecting pipe work and fittings are suitably rated to handle the
predicted pipeline pressure.
If rigid pipe work comes in close proximity to the pumphead, a drop out section
of pipe work will simplify tube replacement.
Ensure that the controlled waste blanking plug is in position if the controlled
waste port is not in use. See below.
It is advisable to use controlled waste pipe work if pumping hazardous, aggres-
sive or abrasive fluids or products which will harden in contact with air.