Pratissoli MW Serie Manuel D'utilisation Et D'entretien page 53

5. Use pressure gauges suitable to withstand pulsating loads
typical of the plunger pumps.
6. During the design stage, keep in mind the line load losses
which result in a drop in pressure during use with respect
to the pressure measured on the pump.
7. For those applications where pulses produced by the
pump on the outlet line may prove harmful or unwanted,
install a pulsation dampener of sufficient size.
9.9 Calculation of the internal diameter of the
duct pipes
To determine the internal diameter of the duct, refer to the
following diagram:
Suction duct
With a flow rate of ~ 400 l/min and a water velocity of 1 m/sec.
The graph line joining the two scales meets the central scale,
showing the diameters, corresponding to a value of ~ 90 mm.
Outlet duct
With a flow rate of ~ 400 l/min and a water velocity of 5.5 m/
sec. The graph line joining the two scales meets the central
scale, showing the diameters, corresponding to a value of ~
40 mm.
Optimal speeds that can be obtained with the Booster
pump:
- Suction: ≤ 1 m/sec.
- Outlet: ≤ 5.5 m/sec.
The graph does not take into account pipe
resistance, valves, load loss produced by the length
of the ducts, the viscosity of the liquid pumped or
the temperature itself.
If necessary, contact our Technical or Customer
Service Departments.
9.10 V-belt transmission
As indicated in par. 9.1 in exceptional cases only, the pump
can be controlled by a V-belt system.
For proper layout sizing, consult with our Technical or
Customer Service Departments.
9.11 Transmission of power from the second PTO
Upon request, MW series pumps can be supplied with an
auxiliary PTO on the opposite side to the drive.
Transmission can be carried out:
- By means of the V-belts
- By means of the joint
By means of the V-Belts, withdrawable Max Torque is: 150 Nm
corresponding to 12.5 kW (17HP) at 800 rpm.
By means of the joint, withdrawable Max Torque is: 220 Nm
corresponding to 18.4 kW (25HP) at 800 rpm.
With transmission by means of the joint, pay
particular attention to perfect alignment so that
no transverse forces are generated on the pump
shaft.
For applications differing from those specified
above, contact our Technical or Customer Service
Departments.
10 START-UP AND OPERATION
10.1 Preliminary checks
Before start-up, ensure that:
The suction line is connected and pressurised
(see chapter 9): the pump must never run dry.
1. The suction line ensures a hermetic seal over time.
2. Any shut-off valves between the supply source and
the pump are fully open. The outlet line during is free
discharge, to permit air present in the pump head to come
out quickly and therefore favour fast priming.
3. All suction and outlet fittings and connections are
properly tightened.
4. The coupling tolerances on the pump/transmission axis
(half-joint misalignment, Cardan joint tilt, belt pulling,
etc.) remain within limits required by the transmission
manufacturer.
5. Oil in the pump casing is at the required level, verified with
a dipstick (pos. , Fig. 8).
In case of prolonged storage or long-term
inactivity, you need to restore the proper
functioning of the suction valves by opening the
three valve-lift devices (see pos. ‚ Fig. 9). Make
sure you have closed the valves before starting
the pump.
For the "work" and "rest" positions, see Fig. 10.
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Fig. 8