Rotation Direction; Version Change; Hydraulic Connections; Pump Supply - Pratissoli HF Serie Manuel D'utilisation Et D'entretien

Replace the oil filling hole closing service
plug (red) positioned on the rear casing cover.
Check the correct quantity with the oil dipstick.
The oil dipstick must always be reachable, even
when the unit is assembled.
The pump shaft (PTO) must not be rigidly
connected to the drive unit.
The following types of transmission are
recommended:
‑ Hydraulics by flange, for proper application
consult with our Technical or Customer Service
Departments.
‑ V‑belts.
‑ Universal joint (comply with the maximum
working angles recommended by the
manufacturer).
‑ Flexible coupling.
9.2

Rotation direction

The rotation direction is indicated by an arrow located on the
casing near the drive shaft.
From a position facing the pump head, the rotation direction
will be as in Fig. 5.
LH SIDE
clockwise
9.3

Version change

The pump version is defined as right when:
Observing the pump facing the head side, the pump shaft
must have a PTO shank on the right side.
The pump version is defined as left when:
Observing the pump facing the head side, the pump shaft
must have a PTO shank on the left side.
Note. The version shown in Fig. 5 is right.
The version can only be modified by trained and
authorised personnel and carefully following the
instructions below:
1. Separate the hydraulic part from the mechanical
part as indicated in chapter 2 par. 2.2.1 of the
Repair manual.
2. Turn the mechanical part 180° and reposition
the rear casing cover in such a way that the
oil dipstick is turned upward. Reposition the
lifting bracket and relative hole closing plugs
in the upper part of the casing. Finally, properly
reposition the specification label in its housing
on the casing.
Make sure that the lower casing draining
holes in correspondence with the pistons are
open and not closed from the plastic plugs
provided for the previous version.
3. Unite the hydraulic part to the mechanical part
as indicated in chapter 2 par. 2.2.5 of the Repair
manual.
9.4
In order to isolate the system from vibrations produced by
the pump, it is advisable to make the first section of the duct
adjacent to the pump (both suction and outlet) with flexible
piping. The suction hose must be sufficiently rigid to prevent
deformation due to the negative pressure exerted by the
action of the pump.
9.5
To obtain the best volumetric efficiency, feed the pumps with
a positive head (NPSHr).
The recommended value, measured on the head suction
flange, is given in the following table:
NPSH (m)
r
The values given apply to the rated speed of
rotation; otherwise, contact our Technical or
Customer Service Departments.
For any supply conditions other than those
specified above, contact our Technical or
Customer Service Departments.
9.6
For smooth operation of the pump, the suction line must have
the following characteristics:
1. Minimum internal diameter as indicated in the graph in
par. 9.9 and in any case equal to or exceeding that of the
pump head.
Localised restrictions should be avoided along the
piping, as these can cause pressure drops resulting
in cavitation. Avoid 90° elbows, connections with
RH SIDE other piping, restrictions, reverse gradients, inverted
anticlockwise
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
Fig. 5
hermetic seal through time.
4. Prevent the pump from emptying when it is stopped,
including partial emptying.
5. Do not use 3 or 4‑way hydraulic fittings, adapters, swivel
joints, etc. as they could jeopardise 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. Provide for proper guards inside the tank to prevent that
water flow from the bypass and the tank supply line can
create vortexes or turbulence near the pump supply pipe
port.
10. Make sure the suction line is thoroughly clean inside
before connecting it to the pump.
27

Hydraulic connections

Pump supply

HF 18
HF 20
WK355 HF 22N
2.5 4.0
Suction line
HF 25
HF 22
HF 25N
HF 25N‑F
4.0 4.5