Do's And Do Not's - Watson-Marlow 501CC Manual Del Usuario

All Watson- Marlow ATEX rated pumpheads include provision for the prevention and dissipation of
electrostatic charge. In order to dissipate electrostatic charge effectively there must be sufficient electrical
contact between the pumphead and the suitably earthed drive.
It is imperative that the 500, 600 and 700 series ATEX pumps are earthed. The pumphead
guard, track, gearbox and motor and baseplate (where applicable) already have earth
straps installed. The user must ensure that these earth straps are connected to a suitable
earth point on installation.
It is possible to check the effectiveness of any earth connection by measuring its electrical resistance. To
ensure reliable dissipation of static, the maximum resistance from the earth point
identified above to earth should not exceed 1 MOhm.
Peristaltic tubing is insulating and so its use should be limited to the length adjacent to the pumphead.
Earthed, conductive pipework should be used elsewhere in the system.
AC motor/Air motor
Please refer to the manufacturer's instructions as supplied with the ATEX certified motor.
9.1

Do's and do not's

Do not build a pump into a tight location without adequate airflow around the pump.
Do keep delivery and suction tubes as short and direct as possible 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 (not usually needed) must not restrict the flow. Any valves in the flow line must be open
when the pump is running.
Do use suction and delivery pipes equal to or larger than the bore of the tube in the pumphead. When
pumping viscous fluids use pipe runs with a bore several times larger than the pump tube.
Do ensure that your system fluid supply and discharge pipework is suitable for the hazardous
environment in which the pump is operating and doesn't allow for the accumulation of electrostatic
charge.
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.
Do keep the pumphead track and all moving parts clean and free from contamination and debris.
Do run at slow speed when pumping viscous fluids. Flooded suction will enhance pumping
performance in all cases, particularly for materials of a viscous nature.
Do limit peristaltic tubing to the length adjacent to the pumphead because peristaltic tubing is insulating.
Electrostatic testing has been used to determine which Watson- Marlow tubing is suitable for use in
hazardous environments. Refer to pumphead manual for more information. Earthed, conductive
pipework should be used elsewhere in the system.
When using Marprene or Bioprene continuous tubing, do re- tension the tube after the first 30
minutes of running.
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