General Pump VH - Manual (Page 7)

GENERAL PUMP
A member of the Interpump Group
VH SERIES
Page 7
9. PUMP INSTALLATION
9.1 Positioning
The pump should be installed flat on a rigid base by
means of the four M14 threaded feet. The base should
be rigid enough to avoid any misalignment or flexing of the
pump/transmission coupling axis due to the torque
involved during operation.
9.5 Suction line
Plunger pumps are not self priming therefore a positive
suction head should always be provided. Information for
the correct suction line:
1. Internal diameter should be at least 3”, in any
point, possibly larger depending on the drop in
pressure due to the length and shape of the line.
2. Should be as straight as possible minimizing changes
in size and direction and positioned in such a way
to allow air pockets and bubbles to escape.
3. Should be perfectly airtight.
4. Should be completely free from 90o elbows, diameter
reductions, counter slopes, “T” connections and
should not be connected to other pipelines.
5. Should positioned in such a way to prevent the pipe
emptying after the pump stops.
6. Do not use high pressure flexible hoses for the suction
line.
7. Do not use high pressure hydraulic fittings like 90o
elbows, high pressure adapters, high pressure 3 or
4 way nipples and so on.
8. Do not install any kind of detergent injector along the
suction line.
9. Do not install standing valves, check valves or other
kind of one-way valves.
10. Make sure that the feed tank capacity and the water
minimum level do not give rise to turbulence at the
tank outlet port, which, in turn, might create
cavitation at the pump.
11. Do not connect the by-pass line from the valve directly
to the pump suction line.
12. The water flow from the valve should be directed back
in the tank. Make sure that the by-pass and tank
feeding flows to not give rise to turbulence at the
tank outlet port, which, in turn, might create
cavitation at the pump. Proper baffle plates should
be provided inside the tank.
13. Before connecting the suction line to the pump inlet
port make sure the pipe is perfectly clean inside.
9.2 Direction of rotation
Fig. 5 shows the correct direction of rotation looking at the
pump from the fluid end side. Two arrows stamped on the
crankcase nearby the crankshaft provide the information
as well.
9.3 Water connections
In order to isolate the high pressure equipment from the
pump vibrations it is suggested, where applicable, to use
flexible hoses for both suction and delivery lines at least
for the first length.
9.4 Suction Line
VH pumps require an inlet pressure at the suction port
of at least 73 PSI up to 100 PSI. The feeding pump should
be of a centrifugal type , supply at least twice the rated VH
pump flow rate at the above required pressures in any
working condition at any pump soeed. The feed pump
should be operated independently from the plunger pump.
The VH pump should be started only when the inlet
pressure is at least 73 PSI. A pressure switch to control the
correct inlet pressure should always be installed in the
suction line after the filters.