Watson-Marlow 401U - Manual (Page 7)

7
400D, 400DM2 and 400DM3 pumpheads
Tube life and performance against pressure
The pressure and the suction height can be increased by compressing the spring in the sprung track pin. A
smaller gap between the rollers and track will give better performance against pressure but will reduce tube
life.
Other application factors that will influence tube life in peristaltic pumps are pump speed and number of
rollers (roller impacts/minute), temperature, chemical compatibility of the duty fluid and viscosity of the duty
fluid. Several tubing materials are available offering different levels of life expectancy. The tubing’s
dimensional tolerances from the manufacturing process will also influence the life of a tube.
This means that it is impossible to predict tube life in any particular application.
In perfect conditions of no suction or discharge pressure, in a clean environment at normal room temperature,
and pumping water, nominal tube life may be:
Marprene and Bioprene less than 6,000 hours
Silicone less than 250 hours
Others less than 100 hours
The factors highlighted above will tend to reduce tube life. Users are advised to determine likely tube life
in their application and make routine tube changes at suitable intervals.
Key Safety Information
Before changing the tubing in the pumphead
• Ensure that there is no pressure, liquid or gas in the pipeline.
• Disconnect the pump from the mains to prevent the pump from starting unexpectedly.
• Always replace any protective guard after tube changeover.
• If a tube failure has occurred, ensure that any product in the pumphead has been allowed to drain to
a safe area.
• Ensure that protective clothing and eye protection are worn if aggressive products are being pumped.
400D pumphead setup (used on 401U/D pump)
The 400D pumphead is designed to accept 1.6mm wall standard laboratory tubing from 0.5mm bore up to
3.2mm bore. Care should be taken to establish the normal tube life experienced within a set of operating
parameters. Subsequent tubing replacement should be scheduled within the normal expected life of a
tube. This will avoid unnecessary tube failure and unplanned pump maintenance.