DE20207106U1 - Device for controlling suction valves - Google Patents

Description

G 10882 EN

Wepuko Hydraulik GmbH & Co.

Pump and compressor factory

Max-Planck-Strasse 10

72555 Metzingen

Device for controlling suction valves

The invention relates to a device for controlling suction valves of high-pressure piston pumps, in which the suction valves are arranged coaxially to the pressure valves and to the pump pistons. It is already known in high-pressure piston pumps with several cylinders to make the pump switchable depending on the operating and usage conditions of the pump, whereby only individual cylinders can be switched off. DE 30 28 396 A1 describes, for example, high-pressure piston pumps in which the suction valves are actuated by force control. In some of the high-pressure piston pumps described, the stroke movement of the closing element of the suction valve is arranged perpendicular to the direction of movement of the associated pump piston, which can, however, lead to breakage of the pump body in high-pressure piston pumps that operate at pressures above 400 bar. The above-mentioned publication also describes piston pumps with a so-called central valve arrangement in which the suction valve and the pressure valve are arranged coaxially to the pump piston. With this valve arrangement, the pump housing is subjected to much lower loads when switching the pump cylinder than

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with a T-shaped arrangement of the suction and pressure valves and the pump pistons. However, due to space constraints, operating the suction valves is more difficult here than with a T-shaped arrangement of the valves and the pump pistons. In the above-mentioned publication, a lever mechanism is proposed for switching such a suction valve, but this is very susceptible to wear, particularly in the area of the joints.

The present invention is based on the object of proposing a device for switching the suction valves of high-pressure piston pumps with a central valve arrangement, which is simple in construction and thus not susceptible to wear.

The object is achieved according to the invention with a device for controlling suction valves of high-pressure piston pumps, in which the suction valve is arranged coaxially to the pressure valve and the pump piston, in that it has a switching element that acts on the closing element of the suction valve at an acute angle to the stroke direction of the closing element. This type of actuation of the suction valves avoids the use of lever mechanisms with joints that are susceptible to wear. The oblique guidance of the switching element enables linear actuation of the switching element, whereby the type of drive can be selected differently. In a preferred embodiment, the switching element can be the tappet of a piston of a hydraulic or pneumatic switching cylinder.

The closing elements of the suction valves are usually provided with a conical area. With such a design, it is advantageous if the switching element acts perpendicularly on the conical surface of the conical area, as this optimizes the force transmission to the closing element.

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The device according to the invention can bring about a forced control of the suction valves. For this purpose, for example, a control valve actuated depending on the pump piston movement can be assigned to the switching cylinder, whereby the switching element causes the suction valve to open depending on the position of the pump piston. The switching element can open the closing element against the force of a return spring.

A preferred embodiment of a device according to the invention is explained in more detail below with reference to the drawing.

Show it:

Fig. 1 a cross section through a suction and

Pressure valve arrangement of a high pressure piston pump;

Fig. 2 a sectional view of a section

the suction valve and pressure valve arrangement of Fig. 1 with an actuating mechanism for the suction valve.

Fig. 1 shows a pump body 10 in which a valve seat 11 is arranged. On one side of the valve seat 11, a closing element 12 of a suction valve 13 is arranged. When the suction valve 13 is opened, pump medium can be sucked in from a suction channel 14 by the movement of the pump piston (not shown here). On the opposite side of the valve seat 11, a further closing element 15 of a pressure valve 16 is arranged. If this valve 16 is opened, the pump medium can be pressed into a pressure channel 17 by the pump piston.

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If the pump piston is to be switched off, the closing element 12 of the suction valve 13 can be forcibly opened with the mechanism shown in Fig. 2 against the force of a return spring 18. The pump piston then presses the medium sucked in from the suction channel 14 back into the channel 14, so that no pressure medium is delivered by the pump piston. The closing element 15 of the pressure valve 16 can also be opened against the force of a return spring 19.

Fig. 2 now shows how the suction valve 13 can be opened by force control. For this purpose, the tappet 20 of a piston 21 of a switching cylinder 22 acts on the closing member 12. The closing member 12 has a conical area 12.1, and the tappet 20 engages the conical surface of the area 12.1 approximately perpendicularly. This acute-angled guidance of the tappet 20 to the stroke direction 23 of the closing member 12 enables the closing member 12 to be actuated despite the confined space conditions without lever and joint mechanisms. The piston 21 with the tappet 20 can be actuated against the force of a return spring 24, so that when the tappet 20 is in the rest position, the closing member 12 is always closed.

Claims (6)

1. Device for controlling suction valves ( 13 ) of high-pressure piston pumps, in which the suction valve ( 13 ) is arranged coaxially to the pressure valve ( 16 ) and to the pump piston, characterized in that it has a switching element ( 20 ) which acts on the closing element ( 12 ) of the suction valve ( 13 ) at an acute angle to the stroke direction of the closing element ( 12 ). 2. Device according to claim 1, characterized in that the closing member ( 12 ) has a conical region ( 12.1 ) and the switching member ( 20 ) acts perpendicularly on the conical surface of the conical region ( 12.1 ). 3. Device according to claim 1 or 2, characterized in that the switching element ( 20 ) is the tappet of a piston ( 21 ) of a hydraulic or pneumatic switching cylinder ( 22 ). 4. Device according to one of claims 1 to 3, characterized in that it effects a positive control of the suction valves ( 13 ). 5. Device according to claim 3 or 4, characterized in that the switching cylinder ( 20 ) is assigned a control valve actuated in dependence on the pump piston movement. 6. Device according to one of claims 1 to 5, characterized in that the switching element ( 20 ) opens the closing element ( 12 ) against the force of a return spring ( 18 ).