Metrohm 843 Pump Station with peristaltic pump - Manual (Page 31)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭ 5 Handling and maintenance
843 Pump Station with Peristaltic Pumps ￭￭￭￭￭￭￭￭ 23
￭ Shearing force of the rollers
￭ Twisting or kinking of the tubing
￭ Excessive tubing length under the pressure clamp
￭ Changes in wall thickness
Observe the following when using tubings:
￭ If the tubing is not pulled sufficiently tightly around the rotor, then this
will have a negative effect on the service life of the tubing. The tubing
has a tendency to unfold in such situations. If the tubing is too tightly
pulled, then the flow will be narrowed.
￭ The tubing will last longer if you loosen the pressure clamp when the
pump is not being used.
￭ In order to achieve good repeatability of feed rate following a change in
tubing, it is imperative that you always choose the same tubing length.
￭ Before replacing the tubing turn off the peristaltic pumps with the
mains switch, or pull out the mains cable of the Pump Station in order
to prevent any unintended starting of the pump.
￭ Before replacing the tubing, make sure that all of the liquid has been
pumped out of the tubing.
￭ Loosen the pressure clamp and remove the old tubing.
Note
Use only Pharmed ® tubing as replacements for the pump tubing.
5.3.4 Suitability test for tubings
Place a short piece of the tubing for 48 hours in an enclosed container that
has been filled with the liquid that is to be conveyed. Afterwards, inspect
the piece of tubing for signs of swelling, brittleness or other limitations.
Caution
An incorrectly selected tubing materials can endanger both users and
instruments.