Instruction manual

Page 7 of 23
3. Configuration, Operation, Illustration
The cold water machines of this series mainly comprise of a low speed high
pressure inline plunger pump, which is directly flanged to and driven by a
100 % duty electric motor.
The supply water is directed with the required minimum pressure via a pre-
filter to the high pressure pump which – in connection with the required spray
nozzle – boosts it to the stated/adjusted working pressure. In order to protect
the pump against cavitation due to poor water flow, a low water cut-out is
arranged which stops the machine as soon as the flow pressure drops below
1 bar.
Downstreams of the high pressure pump a locked and sealed unloader valve
is installed which opens as soon as the operating pressure is exceeded by
more than 10 % and returns the water, which cannot be taken by the nozzle,
back into the suction line of the pump.
Model HPCExtreme 330 only: By opening of the rotary handle of the double
lance the working pressure can be adjusted as required.
The machine is equipped with a circulation shut-off system and additionally
with a thermo valve in order to protect the pump against overheating. After
closing the spray pistol the unloader valve opens, and returns the circulating
water back into the suction line. If during that procedure the water temperature
exceeds 60 °C, the thermo valve opens, releases a small amount of hot water,
and cold water can enter the pump. Re-starting and immediate generation of
required/adjusted working pressure is achieved by opening the spray pistol
again, allowing to continue the cleaning task without delay.
The range of applications can be extended by a variety of accessories
available. Contact your local UNITOR representative.