Watson-Marlow 120F/DV - Manual (Page 10)

Watson-Marlow 120 IP31 pumps: general information 8
Valves
Peristaltic pumps are self-priming and self-sealing
against backflow. No valves are required in inlet or
discharge lines. Valves in the process flow must be
opened before the pump operates. Users are
advised to fit a pressure relief device between the
pump and any valve on the discharge side of the
pump to protect against damage caused by acciden-
tal operation with the discharge valve closed.
Pressure advice
In most circumstances,
rotor and tube life are
maximised if the pump-
head is run slowly, partic-
ularly when pumping at
high pressure. Do not
exceed the pressures
shown here.
1.8.2 Do’s and do not’s
Do not build a pump into a tight location without
adequate airflow around the pump.
Do not strap together the control and and external
DC power supply cables.
Do keep delivery and suction tubes as short and
direct as possible - though ideally not shorter than
1m - and follow the straightest route. Use bends of
large radius: at least four times the tubing diame-
ter. Ensure that connecting pipework and fittings are
suitably rated to handle the predicted pipeline pres-
sure. Avoid pipe reducers and lengths of smaller
bore tubing than the pumphead section, particular-
ly in pipelines on the suction side. Any valves in the
pipeline (not usually needed) must not restrict the
flow. Any valves in the flow line must be open when
the pump is running.
Do use suction and delivery pipes equal to or larg-
er than the bore of the tube in the pumphead. When
pumping viscous fluids use pipe runs with a bore
several times larger than the pump tube.
Do site the pump at or just below the level of the
fluid to be pumped if possible. This will ensure
flooded suction and maximum pumping efficiency.
Do keep the pumphead track and all moving parts
clean and free from contamination and debris.
Do run at slow speed when pumping viscous fluids
(though see Pressure advice in 1.8.1 General rec-
ommendations). Flooded suction will enhance
pumping performance in all cases, particularly for
materials of a viscous nature.
120 pumps may be wiped with a damp cloth, but
should not be hosed or immersed. The front of the
pump is further protected against light spillages.
When using Marprene or Bioprene continuous
tubing, do re-tension the tube after the first 30 min-
utes of running.
Tube selection: The chemical compatibility lists
published in Watson-Marlow publications are
guides. If in doubt about the compatibility of a tube
material and the duty fluid, request a Watson-
Marlow tube sample card for immersion trials.
120 pump RMS
pressure ratings
120F + any
pumphead
0 bar
120S+102R
120S+400DM2
120S+400DM3
120U+114DV
120U+400D1
120U+400DM2
120U+400DM3
2 bar