System Design And Installation - Johnson Pump Top Wing Series Manual

The pump is not to be exposed to rapid temperature changes to avoid damage through
sudden expansion/contraction of the pump components.
Pumps for handling abrasive liquids (causing wear) should be selected with care. Please
contact your Johnson Pump distributor for advice.
Important!
If it is proposed to modify the system/duty or to use the pump for transporting liquids
with other characteristics than for which the pump was originally selected always consult
your distributor.
2.3

System design and installation

When a pump is to be incorporated in a system, it is considered good practice to, as far
as possible, minimise the length of the pipes and the number of pipe fittings (tees,
unions, bends etc.) and the restrictions.When designing the suction lines, particular care
should be taken. These should be as short and straight as possible, using a minimum of
pipe fittings to achieve a good product flow to the pump. Always consider the following
when designing a system:
1. Ensure there is space enough around the pump to allow for:
a)
b)
2. Both the suction and the discharge ports must be provided with valves. During
check-up procedures or maintenance work, the pump must be isolated from the
system.
3. The system design, pipes and other equipment must have independant supports to
avoid heavy loads on the pump. In the case of pipe work or other equipment relying
on the pump fixings for support, there is a big risk for serious damage to the pump.
4. For positive displacement pumps as TopWing it is recommended to install some
safeguards, for example:
a)
b)
c)
d)
If the system can be ruined by reversed flow direction, safeguards must be conside-
red for both directions of rotation/flow.
5. It is considered good practice to thoroughly clean all pipework and associated
equipment from the suction port to the discharge port before installation of pump.
This is to avoid the risk of debris entering the pump and causing damage.
6. If possible, pressure gauges should be placed at the suction port and the discharge
port of the pump, so that the system pressures can be monitored. These gauges give
a clear indication of changes in the operating conditions. If a relief valve is
incorporated in the system the gauges will be necessary for setting and checking the
function of the valve.
7. It is very important that the suction condition at the pump inlet meets the NPSH
required of the pump. Failure to observe this can cause cavitation, which leads to a
noisy operation, reduced flow and mechanical damage on the pump and associated
equipment.
A.0500.301/314.A – IM-TW/10.00 GB (0401)
Routine check and maintenance of the complete pump unit, seal area,
drive motor, etc.
Good ventilation for the drive to avoid overheating.
Built-on safety relief valves
External pressure relief valve system for recirculation to tank or
suction side of the pump.
Torque device in the system, mechanical or electrical.
Rupture disc in the discharge pipework.
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