Valves in the process flow must be opened before the pump operates. Users are advised to
fit a pressure relief device between the pump and any valve on the discharge side of the
pump to protect against damage caused by accidental operation with the discharge valve
closed.
9.2
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.
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If your pump is a PROFIBUS variant do ensure that it is installed in accordance with
PROFIBUS installation guidelines.
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Do not allow tight bends in any PROFIBUS signal cable.
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.
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