WO2017102472A1

WO2017102472A1 - Cylinder head for a multi-stage piston compressor

Info

Publication number: WO2017102472A1
Application number: PCT/EP2016/079981
Authority: WO
Inventors: Herr Jörg NICKL
Original assignee: Voith Patent Gmbh
Priority date: 2015-12-14
Filing date: 2016-12-07
Publication date: 2017-06-22
Also published as: DE102015225065B4; CN208686535U; DE102015225065A1

Abstract

The invention relates to a cylinder head (1) for a multi-stage piston compressor for compressing a compressible working medium, comprising a cylinder head upper part (8), a cylinder head lower part (6) and a valve seat plate (9), wherein inlet and outlet valves are arranged in the valve seat plate (9), via which a working space (18) of a first compressor stage and a working space (19) of a subsequent compressor stage can be filled or emptied during the operation of the compressor, subsections of the cylinder head (1) form a suction chamber (4a, b, c) with a working medium inlet (14), a bypass opening (23a) is provided in the valve seat plate (9), via which the working space (18) of the first compressor stage can be connected to the suction chamber (4a, b, c), wherein an idle valve (2a) is provided in the connection. According to the invention, in order to improve the function, a channel (3) having a second bypass opening (23b) is provided in the valve seat plate (9), via which the working space (19) of the subsequent compressor stage can be connected to the suction chamber (4a, b, c).

Description

Cylinder head for multi-stage reciprocating compressor

The invention relates to a cylinder head for a multi-stage reciprocating compressor, which is suitable for compressing a compressible working medium, in particular air, for use in a compressed air supply device in a motor vehicle.

Piston compressor or compressor or air compressor serve the compression of gases, eg. As air, which is used as a working medium for operating various units. Compressors are used, inter alia, in motor vehicles. In operation, such compressors are used, for example, so that a compressed air tank is filled with compressed air until a predetermined pressure level is reached.

A multi-stage reciprocating compressor essentially consists of a base body, in which reciprocating pistons are arranged, and a cylinder head with valves and cooling channels. In operation, ambient air is sucked in through an inlet channel, a suction chamber and valves in the working space of the first compressor stage, compressed and then passed through an intermediate channel in a further or subsequent working space of a compressor stage and further compressed there. In a two-stage reciprocating compressor, the compressed air is then passed through an air treatment unit or control unit in the compressed air tank.

In a motor vehicle, the drive of the compressor is performed by the drive motor of the vehicle. As a rule, no switchable coupling is provided between the drive motor and the compressor so that the compressor is constantly driven, which represents an energy loss or an increased fuel consumption in non-delivery mode.

To minimize such energy losses or to reduce fuel consumption control devices are provided which switch the compressor in an idling mode upon reaching a desired filling pressure in the pressure vessel, so that at least no more compaction work. Such reciprocating compressors are disclosed for example in DE10 2013 001 147 A1 and DE 10 2009 053 133 A1.

In both documents, an idle valve is provided, which is arranged between the suction chamber and working space of the first compressor stage. In both solutions, a bypass is opened so that air conveyed by the compressor flows back into the suction chamber. The compressor itself then runs in idling mode.

However, the two solutions differ fundamentally with respect to the control and the construction of the idle valves. This is self-closing in the first case and self-opening in the second case. Both variants have their advantages and disadvantages, yet it has been shown that the no-load losses with these solutions can not be reduced far enough under certain boundary conditions.

One of the objects of the invention is to propose a cylinder head for a multi-stage reciprocating compressor which further improves the idling characteristics of the reciprocating compressor. According to the invention this object is achieved with a cylinder head according to claim 1 and a multi-stage piston compressor according to claim 1 1. Further advantageous embodiments and preferred variants of the solution are described in the subclaims dependent thereon.

According to the invention, a cylinder head for a multistage piston compressor for compressing a compressible working medium, comprising a cylinder head upper part, a cylinder head lower part and a valve seat plate is proposed. In the valve seat plate of the inlet and outlet valves are arranged, via which a working space of a first compressor stage and a working space of a subsequent compressor stage can be filled or emptied. Portions of the cylinder head form a suction chamber which has a working medium inlet. Furthermore, a bypass opening in the valve seat plate is provided, via which the working space of the first compressor stage can be connected to the suction chamber, wherein an idle valve is provided in the connection.

To improve the cylinder head is proposed that a second bypass opening is provided in the valve seat plate, via which the working space of the following Coming compressor stage is connected to the suction chamber.

The cylinder head is intended in particular for a reciprocating compressor, as used in motor vehicles. In these, the suction chamber is connected to the ambient air or the vehicle filter air via the working medium inlet. When the idle valves are open, the displacements of the compressor stages are connected to the environment via the bypass openings and the suction chamber. This ensures that the piston compressor in idle mode, a defined reduction in power, even if the pressure line remains under pressure.

In one possible embodiment, a single idle valve can be assigned to both bypass openings. Thus, it is achieved that the connection between the displacements and the suction chamber, when switching from the conveying mode, is promoted in the compressed air in a compressed air tank, in the idle mode and vice versa, takes place simultaneously.

In another possible embodiment, each bypass opening is assigned an idle valve. As a result, the bypass openings could also be switched, opened and closed independently of each other.

Furthermore, the idle valves can be positioned in the cylinder head and the control of the valves can be pneumatic. If the idle valves integrated in the cylinder head, the idle valves may include a closing body which is movable against a sealing surface which surrounds the bypass openings.

Furthermore, the idle valves may comprise a spring which hold the closing body in a closed position, wherein the spring of the individual idling valves may be designed differently. As a result, for example, with simultaneous control, a different switching characteristic can be achieved. In order to continue to allow a favorable positioning of the idle valves, a discharge channel may be provided in the valve seat plate, which connects the second bypass opening with the working space of the subsequent compressor stage.

Preferably, the idle valves can be acted upon via a control pressure line with compressed air, so that the closing body of the idle valves against the spring force to be moved in an open position.

Alternatively, however, each idle valve via a separate control pressure line can be acted upon with compressed air, so that the closing body can be moved independently against the spring force in an open position. Advantageously, the cylinder head described can be mounted on a multi-stage reciprocating compressor for compressing compressible media. So it is possible to convert existing reciprocating compressors. For this purpose, only the old cylinder head would have to be replaced with the cylinder head according to the invention.

Further features of the cylinder head or the piston compressor according to the invention and further advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings.

The invention will be explained in more detail with reference to drawings.

In these show:

Figure 1 is the circuit diagram of the improved idle circuit

Figure 2 shows a reciprocating compressor in the operating mode

Figure 3 is an idle valve in detail

Figure 1 shows the circuit diagram of the improved idle circuit according to the invention for a multi-stage compressor, here shown a reciprocating compressor with two compressor stages, each having a working space 18, 19. The first compressor stage, or the working chamber 18 of the first stage, the suction chamber 4a, b associated. Via the working medium inlet 14, the suction chamber 4a, b, and an inlet valve, not shown, the working space 18 can be filled with working medium, in particular ambient air.

The intermediate channel 21 between the displacements 18, 19 is connected once to the working space 18 via the outlet valve (not shown) and to the second-stage working space 19 on the other side via an inlet valve (not shown). The intake and exhaust valves, not shown here, are known to those skilled in the art. For cooling the pre-compressed air discharged from the first stage, a cooler with a cooling channel 10 is provided in the intermediate channel 21 so that compressed air at a lower temperature can be supplied to the working space of the subsequent stage.

The compressed air leaving the subsequent stage is also called APU via an air treatment device with a control device, which is supplied to a compressed air tank.

Each compressor stage is assigned an idle valve 2a, b. The control of the idle valves, for example, as shown here, via the control unit of the APU, by means of which a valve 22 is controlled. In the switching position of the valve 22 shown here, the idle valves 2a, b switch to the idling position. That is, the bypass openings 23a, b between the displacements 18, 19 and the Saugkammerabschnitt 4c are open. There is thus a connection between the environment at the working medium inlet and the displacements 18, 19, whereby the air is no longer compressed during a piston movement.

The compressed air for the control of the idle valves 2a, b can be removed, for example, from the compressed air tank.

Figure 2 shows a reciprocating compressor in the operating mode with a cylinder head 1 in which the idle valves 2 a, b are positioned. Figure 3 shows a possible embodiment of an idle valve in detail. The illustrated idle valves 2a, b are in both representations in the closed position. In this position, the valve body 12 are pressed by the spring 1 1 against the valve seat plate 9. The bypass openings 23a, b are thus closed in this position. To open the idle valves 2a, b they are pressurized via the control air connection 14 and the control pressure chamber 25 with compressed air. As can be clearly seen in Figure 3, the compressed air from the control pressure chamber 25 via the connecting channel 5 in the piston chamber 27. By pressurizing the valve body 12 moves against the spring force along the guide body 13, in an open position. Furthermore, it can be seen how the idle valves are arranged in the cylinder head base 6 and how they are attached to the partition plate 7. In order to keep the structure simple, both idle valves 2a, b are positioned in a portion of the suction chamber 4c. In the upper cylinder part 8, the control pressure chamber 25 is arranged, are controlled via the two idle valves simultaneously, so that as possible a simultaneous circuit of the idle valves. In order to connect the offset to the working space 19 arranged bypass opening 23b with the working space 19 of the subsequent stage, a discharge channel 3 is provided in the valve seat plate.

FIG. 3 shows an alternative idling valve 2. The illustrated idling valve is in the closed position. In this position, the valve body 12 is pressed by the spring 1 1 against the valve seat plate 9. The bypass opening 23a, b is thus closed in this position.

The idling valve essentially comprises a valve body 12, a guide body 13 and a spring element 1 1. Due to this simple structure, the idle valve is only functional when it is installed in a cylinder head.

Thus, it is necessary that the idle valve 2 is fixed to a component of the cylinder head 1, here on the partition plate 7 of the cylinder head. 1 Furthermore, a counter-sealing surface 26b is required, against which the valve body 12 can be pressed with its end face arranged sealing surface 26a. This is here the valve seat plate 9 of the cylinder head 1 and the compressor.

The central component of the idle valve 2 is the guide body 13, which can be made in one piece by the simple structure. Furthermore, the guide body 13 essentially has four sections. The attachment portion 28, the guide portion 29, the piston portion 30 and the head portion 31. The diameters of the individual sections are graduated from one another such that the assembly is very simple and errors or malfunctions can be virtually ruled out.

The sealing of the piston chamber 27 by means of the sealing pack (23a, b) is solved very easily. These are inserted in grooves, in each case at least one sealing packet 23a, b in the guide section 29 and in the piston section 30. Preferably, a sealing pack 23a, b consists of a sliding ring and O-ring. The invention is not limited to a two-stage compressor. Rather, more than two stages can be connected in series, in which case one idle valve per compressor stage can then be provided in each case.

LIST OF REFERENCES

cylinder head

a, b idle valve

relief channel

a, b, c suction chamber, suction chamber channel

connecting channel

Cylinder head lower part

separating plate

Cylinder head shell

Valve seat plate

0 cooling channel

1 spring

2 valve body

3 guide body

4 working medium inlet

5 working medium outlet

6 a, b reciprocating piston

7 compressor housing

8 working room first stage

9 working space second stage

0 cooling water connection

1 intermediate channel

2 valve

3 a, b Bypass opening

4 control air / control air connection5 control pressure chamber

6a, b Sealing surface / counter surface area7 Piston space

8 fixing section

9 guide section

0 piston section

1 head section

2 chamfer

Claims

claims

1 . Cylinder head (1) for a multi-stage piston compressor for compressing a compressible working medium, comprising a cylinder head upper part (8), a cylinder head lower part (6) and a valve seat plate (9), wherein

- In the valve seat plate (9) inlet and outlet valves are arranged, via which a working space (18) of a first compressor stage and a working space (19) of a subsequent compressor stage can be filled or emptied in compressor operation,

Parts of the cylinder head (1) form a suction chamber (4a, b, c) with a working medium inlet (14),

a bypass opening (23a) is provided in the valve seat plate (9), via which the working space (18) of the first compressor stage can be connected to the suction chamber (4a, b, c), wherein an idling valve (2a) is provided in the connection, characterized,

a channel (3) with a second bypass opening (23b) and in the valve seat plate (9) is provided, via which the working space (19) of the subsequent compressor stage can be connected to the suction chamber (4a, b, c).

2. Cylinder head (1) according to claim 1,

characterized,

in that the idling valve (2a) is associated with both bypass openings (23a, b).

3. Cylinder head (1) according to one of the claims,

characterized,

in that each bypass opening (23a, b) is assigned an idling valve (2a, b).

4. Cylinder head (1) according to claim 2 or 3,

characterized,

in that the idling valves (2a, b) are positioned in the cylinder head (1), in particular in the cylinder head lower part (6).

5. Cylinder head (1) according to claim 4,

characterized,

the idle valves (2a, b) are pneumatically controlled.

6. Cylinder head (1) according to claim 4,

characterized,

in that each idling valve (2a, b) comprises a valve body (12) which is movable against a sealing surface (25a, b) which encloses the bypass openings (23a, b).

7. Cylinder head (1) according to claim 4,

characterized,

in that each idling valve (2a, b) comprises a spring (26) which holds the valve body (12), in the non-actuated state, in a closed position.

8. Cylinder head according to claim 1,

characterized,

in that a discharge channel (3) is provided in the valve seat plate (9), which connects the second bypass opening (23b) to the working space of the second stage (19).

9. Cylinder head according to claim 6,

characterized,

the idling valves (2a, b) can be acted upon by compressed air via a common control pressure supply.

10. Cylinder head according to claim 6,

characterized,

that each idle valve (2a, b) can be acted upon by compressed air via a separate control pressure line. Multi-stage piston compressor for compressing compressible media send a cylinder head according to one of claims 1 to 10.