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9.5
Suction line
For smooth operation of the pump, the suction line must have
the following characteristics:
1. Minimum inside diameter as indicated in the graph in par.
9.8 and in any case greater than or equal to the diameter
at the pump manifold.
Localized restrictions should be avoided along the
piping, as these can cause pressure drops resulting
in cavitation. Avoid 90° elbows, connections with
other piping, restrictions, reverse gradients, inverted
U-curves and Tee connections.
2. The layout must be such as to prevent cavitation
problems.
3. Completely airtight and constructed to ensure a perfectly
hermetic seal through time.
4. Prevent the pump from emptying when it is stopped,
including partial emptying.
9.6
Filtration
Two filters must be installed on the pump suction line, positioned as indicated in Fig. 7 and Fig. 7/a.
With a manually activated control valve
Inlet
Supply tank
With pneumatic control valve
Inlet
Supply tank
The filter, which is to be installed as close to the pump as
possible, must be easy to inspect and have the following
specifications:
1. Minimum flow rate at least 3 times the nominal flow rate
of the pump.
5. Do not use 3 or 4-way hydraulic fittings, adapters, swivel
joints, etc. as they could jeopardize pump performance.
6. Do not install Venturi tubes or injectors for detergent
suction.
7. Avoid use of foot valves or other types of unidirectional
valves.
8. Do not recirculate the by-pass valve drain directly to the
suction line.
9. Install suitable baffles inside the tank to prevent the water
flow from the bypass and the tank supply line creating
vortices or turbulence near the pump supply outlet port.
10. Make sure the suction line is thoroughly clean inside
before connecting it to the pump.
11. Install the pressure gauge for checking the booster
pressure near the plunger pump suction port and always
downstream from the filters.
1 Filter 1
2 Booster Pump
3 Filter 2
4 Pressure gauge
5 Pressure switch
6 Plunger pump
Bypass
1 Filter 1
5 Pressure switch
2 Booster Pump
6 Plunger pump
3 Filter 2
7 Pressure gauge
4 Pressure gauge
8 Safety valve
Bypass
2. Inlet/outlet port diameters no smaller than the inlet port
diameter of the pump.
3. Filtration grade between 200 and 360 µm.
36
7 Pressure gauge
8 Safety valve
9 Accumulator
10 Control valve
Fig. 7
9 Accumulator
10 Pneumatic control
valve
Fig. 7/a
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