Viking Pump TSM275: AL-05 - Manual (Page 11)

Page 11
3.1 System Design and Installation.
When incorporating any pump into a system it is considered good practice to minimize piping
runs and the number of pipe fittings (tees, unions, bends etc.) and restrictions. Particular
care should be taken in designing the suction line, which should be as short and straight as
possible with a minimum of pipe fittings to minimize restricting product flow to the pump. The
following should be considered at the design stage of any system:
• Be sure ample room is provided around the pump to allow for:
• Access to the pump and drive for routine inspection and maintenance, i.e. to
remove pump front cover and rotors.
• Ventilation of the drive to prevent over heating.
• The exterior of the pump unit may exceed 68 ° C (154 ° F), appropriate measures must
be taken to warn or protect operators.
• The pump must not be used to support piping. All piping to and from the pump unit
must be independently supported. Failure to observe this may distort the pump head
components or assembly and cause serious consequential damage to the pump.
• Valves should be provided adjacent to the pump suction and discharge connections
to allow the pump to be isolated from the system for routine inspection and
maintenance.
Rotary lobe pumps are of the positive displacement type and therefore an overload
protection device must be provided. This can take the form of:
• An in-line pressure relief system, i.e. external to the pump.
• Incorporation of a torque-limiting device in the drive system.
It is recommended that all piping and associated equipment from the tank to the
discharge point is thoroughly cleaned before installation of the pump to avoid the
possibility of debris entering the pump and causing damage.
Pressure gauges should be installed adjacent to the pump suction and discharge
connections such that system pressures can be monitored. These gauges will
provide a clear indication of changes in operating conditions and where a relief valve
is incorporated in the system, will be necessary for setting and checking the
functioning of the valve.
It is imperative that the suction condition at the pump inlet meets the Net Positive
Suction Head Required (NPSHr) by the pump. Failure to observe this could cause
cavitation, resulting in noisy operation, reduction in flow rate and mechanical damage
to the pump and associated equipment.
The Net Positive Suction Head Available (NPSHa) from the system must always
exceed the Net Positive Suction Head Required (NPSHr) by the pump. Observing the
following general guidelines should ensure the best possible suction condition is
created.
• Suction piping is at least the same diameter as the pump connections.
WARNING
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WARNING
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WARNING