Nilfisk-ALTO NEPTUNE 5-46 PE, Service Manual

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NEPTUNE PE-DE_en_Ver.1.0_October 2010
Function
By-Pass valve function NEPTUNE 7-61PE, 7-66DE, 7-72DE
Operation:
The water from the pump is lead into
the chamber ”A” in the by-pass valve.
From here the water passes through
the holes “B” in the by-pass valve pis-
ton “C” and out to the high pressure
nozzle. When water is pressed
through holes in the piston “C”, there is
a pressure drop over the piston (this
means the pressure is higher on one
side of the piston). This will keep the
valve cone “D” closed against its seat
“E”, because the piston “C” is fixed to
the valve cone.
By-Pass:
When the water consumption stops
(spray handle is released/closed), the
pressure drop over piston “C” disap-
pears, the pressure in the by-pass
valve increases briefly until the safety
valve “F” opens. The safety valve just
opens briefly, and closes again. The
safety valve opens when the pump
pressure overcomes the tension of the
spring in the safety valve. (The safety
valve is adjusted to open 25-30 bar
above normal working pressure). Now
the valve cone “D” lift from its seat “E”,
and water runs in by-pass.
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