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International Service Information
International Service Information
June 24th, 1999
HD 1050 B
New Unit Information
1. Servopress handgun is open.
When the handgun is completely open, water
flows from the pressure chamber (7) through the
non-return valve (6) and both injectors (2+4) to
the high-pressure outlet (1).
The ball (9) is pressed against the valve seat by
the pump pressure, thus sealing the connection
bore (12) to the suction chamber (11).
The pressure gauge (5) indicates the operating
pressure.
The pressure in the connection bore (17) is
approx. 30 bar less due to the injector influence
(4) (control pressure).
2. Servopress handgun is partly closed.
When the handgun is partly closed, the pressure
in the pressure chamber (7) does not increase.
Due to the decreased water flow rate, the
influence of the injector (4) is reduced so that the
control pressure in the connection bore (17)
increases. The increasing control pressure
pushes the overflow valve spindle (16) against
the spring (14) and slightly to the right. The tip of
the spindle pushes the ball (9) off its seat so that
part of the water can flow through the connection
bores (8) and (12) to the suction chamber (11).
3. Servopress handgun is completely
closed.
When the handgun is completely closed, the
pressure in the pressure chamber (7) increases.
The increased control pressure pushes the
overflow valve spindle (16) via the connection
bore (17) against the spring (14) completely to
the right. The tip of the spindle pushes the ball
(9) off its seat, so that the entire water volume
can flow through the connection bores (8) and
(12) to the suction chamber (11).
As soon as the handgun is closed, the non-return
valve (6) closes. Therefore the complete
pressure in the system between handgun and
non-return valve (6) is trapped.
The pump continues running in circulation mode.
4. Servopress handgun is opened.
When the handgun is opened, the entire pressure
in the system dercreases.
The overflow valve spindle (16) is pushed back
to its original position to the left via the spring
(14). The spring (10) and the pump pressure of
the connection bore (8) push the ball (9) back
onto the valve seat.
The connection bore (8) is thereby closed and
the operating pressure can be built up again.
Function of overflow valve
