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EDITION 09 /2015
OPERATING MANUAL
4.4
FUNCTIONING
4.4.1
PUMP
1
Product delivery manifold
2
Product suction manifold
3
Reversing valve unit
4
Compressed air inlet fi tting
5
Pneumatic motor protection
6
Fluid section
7
Grounding connection
8
Product inlet fi tting
9
Product outlet fi tting
10 Safety valve
Generalities
The double-diaphragm pump is operated by a pneumatic reciprocating motor. The dia-
phragms' movement inside the fl uid section (6) is obtained by a hold-and-grasp system
that makes them integral with the motor shaft.
At the end of each phase the compressed air is directed to the opposite chamber by de-
dicated commutating valves named feelers. The motor has a tandem confi guration: two
pistons simultaneously push the pump shaft.
During each stroke of the shaft, the paint is sucked and pumped into the delivery ducts at
the same time.
Pneumatic motor
Thanks to its reversing system (3) the pneumatic motor needs no lubrication. The compres-
sed air supply is obtained by a pressure reducer and a ball valve available on request with
the pump.
The pneumatic motor is equipped with a safety valve containing a pre-loaded spring. The
safety valve is mounted and calibrated in the factory. When the pressure exceeds the max.
allowed operating value, the valve opens and discharges the exceeding pressure.
Safety valve
Besides having the aim to limit the max. inlet pressure of compressed air into the pneuma-
tic motor, the safety valve (10) can be also used as depressurizing valve for the motor. To
depressurize the motor, just pull the dedicated exhaust ring when the ball valve is closed
(part n°3 in the diagram in Paragraph 4.4.2). The ring on the safety valve also allows to
check the good performance of the valve itself.
Use the safety valve ring to depressurize the pneumatic motor, in addition to the pressure
outlet procedure in the fl uid side.
Depressurize the pneumatic motor before any pump disassembly or maintenance work.
PART NO. ZZB028ENG
5
3
10
4
2
C_41_00005
Unica 4-270 N
1
.
9
6
7
8
19
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