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International Service Information
International Service Information
Dec. 22nd,1999
HD 1050 DE Cage
New Unit Information
1. Servopress handgun is open.
When the servopress handgun is completely
open, water flows from the pressure chamber (7)
through the non-return valve (6) and through 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).
The motor runs with operating speed when the
handgun is open.
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 connection bore
(17) 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.
As soon as the handgun is closed, the non-return
valve closes (6). Therefore the entire pressure
in the system between handgun and non-return
valve (6) is trapped.
The pump continues running with decreased
pressure in circulation operation.
The motor continues running via automatic r.p.m.
control with decreased circulation r.p.m.
4. Servopress handgun is opened.
When the handgun is opened, the pressure in
the system decreases.
The overflow valve spindle (16) is pushed back
by the spring (14) to its original position to the
left. 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.
The engine r.p.m. increases to the operating
speed.
Unit function: overflow valve
