Pressure chamber with degassing device

Abstract

The invention discloses a hydrostatic pressure chamber with a degassing device connected at its highest point. The degassing device is connected via a throttle to a tank or to a pressureless leakage area of a hydraulic system in which the pressure chamber to be degassed is arranged.

Description

TECHNICAL FIELD

[0001] The invention relates to a pressure chamber with a degassing device, which can be filled or is filled with a liquid pressure medium. BACKGROUND

[0002] A problem in the operation of hydraulic devices is that the liquid pressure medium, mostly hydraulic oil, is not in the tank for a sufficiently long time to be completely degassed. Therefore, the pressure medium is usually degassed in the hydraulic system, wherein the gas, mostly air, collects at the high points which are not flowed through or at the back cut of the pressure chamber which is not flowed through.

[0003] By this air collection, adverse effects occur in the highly dynamic pressure change in the pressure chamber, such as cavitation or self-ignition (diesel effect).

[0004] At the internet link: https: / / www.sitema.de / de / produkte / zubehoer / ventilation automation, php?thisID0104 An automatic ventilation device is disclosed below, which enables a continuous ventilation of a clamping head, in particular a hydraulic clamping head. For this purpose, the automatic ventilation device is arranged above the line or above the clamping head. In the operation of the clamping head, the automatic ventilation device utilizes the viscosity difference between the hydraulic oil and the air which collects on the automatic ventilation device.

[0005] The disadvantage of such automatic ventilation devices is that they are not suitable for highly dynamic loaded pressure chambers. SUMMARY

[0006] In contrast thereto, it is the task of the invention to provide a pressure chamber with a degassing device, which is suitable for highly dynamic pressure changes.

[0007] This task is solved by a pressure chamber with a degassing device according to the invention.

[0008] Further advantageous design options of the invention are described in other parts of the present disclosure.

[0009] The claimed pressure chamber has at least one high point which is almost or not flowed through by the liquid pressure medium, for example hydraulic oil. The degassing device is connected to one high point or to several high points. A pressureless connection to the tank can be formed or is formed by the degassing device. The degassing device has a volume flow restriction in order to keep the leakage of the pressure medium through the degassing device as small as possible. The pressureless connection can be direct or indirect. The pressure chamber with the degassing device is suitable for highly dynamic pressure changes.

[0010] An indirect variant of this pressureless connection can be guided for example by a region inside the housing, in which also the pressure chamber is accommodated.

[0011] The volume flow limiting device can be formed or have a constant throttle in device technology. The constant throttle can be integrated into a wall of the housing.

[0012] In one embodiment, an internal leakage return device is connected on the output side of the constant throttle. The internal leakage return device can be formed by a passage in a wall of the housing.

[0013] A further constant throttle can be arranged in the internal leakage return device. The further constant throttle can be integrated into a wall of the housing.

[0014] In one embodiment, a supplementary suction valve is arranged parallel to the constant throttle. Preferably, the supplementary suction valve is formed by a check valve which is spring-loaded in the opening direction from the tank to the pressure chamber.

[0015] In one embodiment, the volume flow limiting device is formed by a shut-off valve.

[0016] In one embodiment, the volume flow limiting device has a shut-off valve in addition to the constant throttle.

[0017] The shut-off valve is preferably pre-tensioned by a spring into the closed position and is switchable into the open position by an actuator.

[0018] The shut-off valve can have a check valve by which the connection from the pressure chamber to the tank is interrupted in the closed position of the shut-off valve. Thus, a supplementary suction function is given.

[0019] The shut-off valve can be configured as a seat valve which interrupts the connection from the pressure chamber to the tank without leakage in the closed position.

[0020] The shut-off valve can be configured as a quick switch valve in order to achieve a short-term degassing at short-term operating pauses of the system or of the pressure chamber in order to thus minimize the loss power of the system. BRIEF DESCRIPTION OF DRAWINGS

[0021] In the drawings, various embodiments of a pressure chamber with a degassing device according to the application are shown. Therein, it is shown:

[0022] Fig. 1 A first embodiment of a pressure chamber with a degassing device according to the application is shown,

[0023] Fig. 2 A second embodiment of a pressure chamber with a degassing device according to the application is shown,

[0024] Fig. 3A third embodiment of a pressure chamber with a degassing device according to the application is shown, and

[0025] Fig. 4 A fourth embodiment of a pressure chamber with a degassing device according to the application is shown. DETAILED DESCRIPTION

[0026] In Figs. 1 to 4 each case, an annular hydraulic pressure chamber 1 for a liquid pressure medium, for example hydraulic oil, is shown, which extends rotationally symmetrical with respect to a longitudinal axis 4. Here, a radially outer wall portion 6 of the pressure chamber 1 has a radial constriction, thereby creating two radially enlarged regions. These two radially enlarged regions form their high points 2a and 2b due to the horizontal arrangement of the longitudinal axis 4 of the pressure chamber 1, through which the pressure medium does not or hardly flows.

[0027] The two high points 2a and 2b are degassed, in particular ventilated, via respective lines, which are formed as respective channels in the wall portion 6. A volume flow restriction device according to the application is arranged downstream and above the junction 8 of the two channels.

[0028] According to Fig. 1 , the volume flow restriction device is formed by a constant throttle 10. Downstream of the junction 8, a line 12 is connected, which leads to a tank T without pressure. Since gas always collects in the pressure chamber 1, i.e. in the two high points 2a, 2b, above, it escapes to the tank T. In order to keep the leakage and thus the power loss as small as possible, a constant throttle 10, which restricts the volume flow, is installed into this line 12.

[0029] According to Fig. 2 , the volume flow restriction device is formed by a constant throttle 10 and a shut-off valve 14. The degassing device corresponds to the degassing device according to the first embodiment in Fig. 1 , with the difference that a shut-off valve 14 is also installed between the constant throttle 10 and the tank T, which is designed as a fast switching valve. This shut-off valve is opened only at suitable times of the operating cycle by means of its actuator, thereby further reducing the power loss and ensuring functionality in (leakage) critical processes.

[0030] According to Fig. 3 , the volume flow restriction device is formed by a constant throttle 10, to the output of which a line 13 is connected, which forms an internal leakage return device that leads back without pressure to a leakage area 15 of the system. In the line 13, a constant throttle 16 is also installed in order to restrict the leakage.

[0031] According to Fig. 4The volume flow restriction is formed by a constant throttle 10 and a supplementary suction valve 18. Downstream of the junction 8, the constant throttle 10 and the supplementary suction valve 18, which is configured as a non-return valve, are arranged in parallel, the supplementary suction valve shutting off the throughflow from the pressure chamber 1. Downstream of these two elements 10, 18, the line is connected again in the direction of the tank T by a junction 20. A dead volume 22 for pressure medium is located at the junction 20. This dead volume 22 is connected pressurelessly to the tank T and is limited to a pressure medium volume which is predefined geometrically.

[0032] As long as the pressure in the pressure chamber 1 is greater than the tank pressure, the volume flow is discharged to the tank T by means of the constant throttle 10, analogously to the first embodiment, and the pressure chamber 1 is kept gas-free. If an undesired underpressure occurs in the pressure chamber 1, pressure medium can be sucked from the dead volume 22 into the pressure chamber 1 by means of the supplementary suction valve 18. The underpressure can thereby be limited or reduced.

[0033] The invention discloses a hydrostatic pressure chamber 1 which has a degassing device connected at its highest points 2a, 2b. The degassing device is connected by means of a throttle 10 to a tank or to a pressureless leakage area 15 of a hydraulic system, in which the pressure chamber 1 to be degassed is arranged.

[0034] List of reference signs

[0035] 1 pressure chamber

[0036] 2a, 2b high points

[0037] 4 longitudinal axis

[0038] 6 wall portion

[0039] 8 junction

[0040] 10 constant throttle

[0041] 12 line

[0042] 13 passage

[0043] 14 shut-off valve

[0044] 15 leakage area

[0045] 16 further constant throttle

[0046] 18 supplementary suction valve

[0047] 20 junction

[0048] 22 dead volume

[0049] a open position

[0050] b closed position

[0051] T tank.

Claims

1. A pressure chamber (1) having at least one elevated point (2a, 2b) not permeated by a liquid pressure medium, said pressure chamber being adapted for highly dynamic pressure changes, wherein a degassing device (2) is connected to said elevated point, wherein, The degassing device (2) can establish or establish a pressureless connection (12, 13) with the storage tank (T), and wherein the degassing device has a volume flow limiting device to keep the leakage of the pressure medium through the degassing device (2) as small as possible.

2. The pressure chamber according to claim 1, wherein, The volume flow limiting device is formed by a constant throttling section (10).

3. The pressure chamber according to claim 2, wherein, An internal leakage return device is connected to the output end of the constant throttling section (10).

4. The pressure chamber according to claim 3, wherein, The internal leakage return device is formed through a channel (13) in the wall (6) of the pressure chamber (1).

5. The pressure chamber according to claim 3, wherein, Another constant throttling section (16) is arranged in the internal leakage return device.

6. The pressure chamber according to claim 2, wherein, A supplementary suction valve (18) is arranged parallel to the constant throttling section (10).

7. The pressure chamber according to claim 2, wherein, The volume flow limiting device has a shut-off valve (14).

8. The pressure chamber according to claim 7, wherein, The constant throttling section (10) is arranged between the pressure chamber (1) and the shut-off valve (14).

9. The pressure chamber according to claim 7 or 8, wherein, The shut-off valve (14) is preloaded to the closed position (b) by a spring, and wherein the shut-off valve (14) can be switched to the open position (a) by an actuator.

10. The pressure chamber according to claim 9, wherein, The shut-off valve (14) has a check valve that cuts off the connection from the pressure chamber (1) to the tank (T) in the closed position (b).

Images