Watson-Marlow 205S User Manual
Page 8
8
CA cassette removal
Lift the cassette release lever and pull out the cassette.
With care, a single cassette can be removed for tube changing without stopping the drive and disturbing the
pumping action of other cassettes.
All cassettes should be in position in the pumphead during normal running, even if some
do not contain tubing. Do not place fingers inside the pumphead.
CA Cassette adjustment and flow rates
Flow rates for pumping water at 20C with zero suction and delivery pressure in PVC tubing, with clockwise
rotation of the pumphead are published at the back of this manual.
Dedicated occlusion adjustment with a vernier indicator has been incorporated into the cassette. This is to enable
repeatable accurate flow rates despite variations that may be caused by the system or when pumping fluids other
than water.
The track geometry has been designed so that when the indicator is at the centre position it is indicating the
normal set-up.
To adjust, pull out the adjusting knob and turn. To lock, push back.
Moving the indicator towards the '+' will increase the track occlusion (reduced roller/track gap) enabling higher
pressures to be obtained without a fall off in flow rate.
Moving the indicator towards the '-' will reduce the occlusion. Remember that higher the occlusion, the shorter the
tube life.
The mechanism also enables small adjustments in the flow rate. This is particularly useful when using a number
of channels where the inter channel flow rate is critical. As a guide only, one graduation move will vary the flow by
approximately 1%
Care and maintenance
When the pumphead needs cleaning, switch the drive off and isolate it from the mains. Remove the cassettes from
the pumphead and remove the tubing. Wash the cassettes in water and mild detergent.
If fluid has been spilled into the pumphead, removal of the pumphead from the drive will make cleaning easier.
Periodically, inspect all moving parts for wear and ensure all bearings and rollers are free to rotate.