Watson-Marlow 505Du - Manual (Page 25)

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Fit the other end of the tubing into the second spring loaded clamp, ensuring that
the tubing is not slack in the pumphead, since this can reduce tube life.
Close the crank handle and shut and lock the guard.
After the pump has been started, open the downstream clamp for a short time,
so that the tube can find its natural length.
The 501RL pumphead is fitted with four-position tube clamps, to accommodate
various tube diameters, which can be adjusted by pushing in or pulling out the
bars at the top of the upper clamp and the bottom of the lower clamp. Set the
clamps so that the minimum necessary pressure is applied to the tubing.
Roller adjustment
The 501RL has a factory set gap of 2.6mm between the rollers and the track and
is suitable for tubing having wall thicknesses of between 1.6 and 2.0mm.
Adjustment of the gap will be required if tubing having a wall thickness of less
than 1.6mm is required. There is an adjusting screw on each of the two roller
arms, and each of these screws will require adjustment. The correct gap is twice
the wall thickness less twenty percent. Correct adjustment is important: over
occlusion will reduce tube life; under occlusion will reduce pumping efficiency.
To change the gap setting, turn each adjusting screw clockwise to increase the
gap, or anticlockwise to decrease the gap. A full turn changes the gap by 0.8mm.
To restore the original settings of 2.6mm, turn the adjusting screws until both
rollers are just touching the track, then tighten each screw by three and a quarter
turns.
Care and maintenance
If aggressive liquids are spilled on to the pumphead, the head should be
removed and cleaned using a mild solution of detergent and water. Remove any
tubing from the pumphead, and swing out the crank handle to expose the rotor
retaining screw. Turn the screw anticlockwise one turn to release the collet, and
withdraw the rotor from the shaft. Unscrew the track retaining screw and detach
the track from its spigot.
Check moving parts of the rotor from time to time for freedom of movement.
Lubricate pivot points and rollers occasionally with a light lubricating oil. To
obtain effective lubrication of the roller spindles, remove the rotor from the
pumphead and clean thoroughly prior to applying a light machine oil.