8.2
Dos and don'ts
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Do not build a pump into a tight location without adequate airflow around the pump.
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Do keep delivery and suction tubes as short and direct as possible - though ideally not
shorter than one metre - and follow the straightest route. Use bends of large radius: at least
four times the tubing diameter. Ensure that connecting pipework and fittings are suitably
rated to handle the predicted pipeline pressure. Avoid pipe reducers and lengths of smaller
bore tubing than the pumphead section, particularly in pipelines on the suction side. Any
valves in the pipeline must not restrict the flow. Any valves in the flow line must be open
when the pump is running.
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Do ensure that on longer tube runs at least one metre of smooth bore, flexible tubing is
connected to the inlet and discharge port of the pumphead to help to minimise impulse
losses and pulsation in the pipeline. This is especially important with viscous fluids and when
connecting to rigid pipework.
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Do use suction and delivery pipes equal to or larger than the tubing diameter bore. When
pumping viscous fluids use pipe runs with a bore several times larger than the pump tube.
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Do site the pump at or just below the level of the fluid to be pumped if possible. This will
ensure flooded suction and maximum pumping efficiency.
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Do run at slow speed when pumping viscous fluids. Flooded suction will enhance pumping
performance, particularly for materials of a viscous nature.
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Do recalibrate after changing tubing, fluid or any connecting pipework. It is also
recommended that the pump is recalibrated periodically to maintain accuracy.
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Do not pump any chemical not compatible with the tube or pumphead.
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Do not run the pump with no tube or element fitted to the pumphead.
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Do not strap the control and mains cables together.
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Do ensure if your product has an N module, that the module is fitted with the seals intact
and properly located. Ensure that the holes for the cable glands are properly sealed to
maintain the IP/NEMA rating.
Tube selection: The chemical compatibility guide published on the Watson Marlow website is for
guidance. If in any doubt about the compatibility of a tube material and the duty fluid, request a
Watson-Marlow tube sample card for immersion trials.
When using Marprene or Bioprene continuous tubing, do re-tension the tube after the first 30
minutes of running.
m-730en-en-09 02-02-22
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