Watson-Marlow 621CC - Manual (Page 18)

16 620RE, 620RE4 and 620R Key safety
information

For close-coupled drives, ensure that the pump is isolated from mains voltage.
 Ensure that there is no pressure in the pipeline.

If a tube failure has occurred, ensure that any product in the pumphead has been
allowed to drain through the controlled waste to a suitable drain.

Ensure that protective clothing and eye protection are worn if hazardous products are
being pumped.
17 620RE, 620RE4 and 620R Safe-guarding
 Primary safety on 620 series pumps is provided by the tool-lockable pumphead
guard. On electrically-powered cased 600 series pumps, secondary (backup)
protection is provided in the form of an electrical interlock which stops the pump if
the pumphead guard is opened (and only for so long as the guard is opened). The
electrical interlock on cased pumps should never be used as primary protection.
Always disconnect the mains power supply to the pump before opening the
pumphead guard.

Only primary protection through the tool-lockable guard is provided on pneumatically
powered 621 close-coupled pumps.

Primary protection through the tool-lockable pumphead guards is provided as
standard on 621 series industrial AC motors. Secondary (backup) protection is
available in the form of an electrical interlock which stops the pump if the pumphead
guard is opened (and only for so long as the guard is opened). The electrical interlock
on close-coupled pumps should never be used as primary protection. Always
disconnect the mains power supply to the pump before opening the pumphead
guard.
18 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 working pressure, this pump will generate in excess of 4 bar
working pressure if pipeline restrictions are in place. In instances where it is critical
that a working pressure of 4 bar is not exceeded, pressure relief valves should be
installed in the pipeline.

For pumping duties of 2-4 bar pressure, use standard STA-PURE tube elements or 73
Shore hardness Marprene/Bioprene. "TM" in the tube element’s product order code
denotes suitability for this pressure.

To maintain performance at pressures above 2 bar, avoid running the pumphead
below 50 rpm. If low-flow, high-pressure operation is necessary, switching to a
smaller tube is recommended.
 When pumping duties of 0-2 bar pressure, use 64 Shore hardness elements or the
standard range of continuous peristaltic pump tubing.

Viscosity handling is maximised by using 73 Shore hardness 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.
Before opening the pumphead guard please ensure that the
following safety directions are followed.
Page 18 of 46 Watson-Marlow Bredel E-Manuals
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