WO2016169977A1

WO2016169977A1 - Switching assembly, in particular for processing compressed air

Info

Publication number: WO2016169977A1
Application number: PCT/EP2016/058739
Authority: WO
Inventors: Fabian PRINSEN
Original assignee: Knorr-Bremse Systeme für Nutzfahrzeuge GmbH
Priority date: 2015-04-22
Filing date: 2016-04-20
Publication date: 2016-10-27
Also published as: DE102015106157A1; CN107548438A; CN107548438B; DE102015106157B4; EP3286439A1

Abstract

The invention relates to a pneumatic or hydraulic switching assembly comprising at least one device (1, 2) that can be switched from a first operating state to a second operating state by the application of pressure to a pneumatic or hydraulic control input (1a, 2a). According to the invention, a control volume (3, 3a, 3b) for a pressure medium is connected before the control input. Said control volume can be connected to a source (1, 5) for a pressure medium by means of a first solenoid valve (4) or by means of a series connection of two valves (4, 6). Furthermore, said control volume has at least one outlet (7) controlled by means of a second solenoid valve (6) or the series connection and/or at least one throttled outlet (7) for the pressure medium. It was recognized that, in such a switching assembly, the solenoid valves (4, 6) must be supplied with current only for much shorter times than according to the prior art. The switching state that is input by means of the first solenoid valve (4) can be preserved as long as desired without current. Thus, the valves (4, 6) must be supplied with current only when the switching state must be changed. In the case of such brief demands, a considerably larger range of supply voltages is permissible for a given internal resistance of the solenoid valve (4, 6). This greater range can be used to design the switching assembly as a whole for lower supply voltages.

Description

Switching arrangement, in particular for compressed air treatment

The invention relates to a pneumatic or hydraulic switching arrangement. State of the art

Electronically controlled systems for compressed air preparation generally convert the control commands from the control electronics via solenoid valves. Such systems are known for example from DE 10 2006 034 762 B3.

Although the control of the compressed air preparation via solenoid valves is extremely flexible, but requires the exact location of each solenoid valve between the inner resistance of the solenoid valve and the existing

Supply voltage. If the internal resistance is too small, the valve may overheat. If the inner resistance is too great, the current is too low, so that no sufficient switching force can be exercised. Especially in vehicles, the

Supply voltage depending on the state of charge of the battery, and due to the supply losses also depending on the distance of the solenoid valve from the location of the battery, vary considerably.

If a solenoid valve is mounted close to the controlling control unit, it can be controlled in terms of percentage clocked, so that the effective

Voltage supply can be adjusted independently of the supply voltage. However, then the supply line from the controller to the device valve as an antenna that emits a high level of electromagnetic interference. Therefore, one is clocked control of solenoid valves often not possible. Solenoid valves that have both a large torque and are designed for continuous operation are expensive. Task and solution

It is therefore the object of the invention to provide a switching arrangement available in which the scope for the coordination between the inner resistance of the solenoid valve used and the supply voltage is greater than in the prior art.

This object is achieved by a switching arrangement according to the main claim. Further advantageous embodiments will be apparent from the dependent claims.

Subject of the invention

In the context of the invention was a pneumatic or hydraulic

Scarf tanordnung developed. This arrangement comprises at least one device which is switchable by pressurizing a pneumatic or hydraulic control input from a first operating state to a second operating state.

According to the control input is preceded by a control volume for a pressure medium. This control volume is connectable by a first solenoid valve and / or by a series connection of this first solenoid valve with a second solenoid valve with a source of pressure medium. Furthermore, it has at least one by a second solenoid valve and / or by the

Connecting the first solenoid valve with the second solenoid valve controlled outlet and / or at least one throttled outlet for the

Pressure medium, wherein optionally also one and the same outlet both by a second solenoid valve controlled, as well as can be throttled. Particularly preferably, the control volume is otherwise completed. In this case, the first solenoid valve and / or its series connection with the second solenoid valve can be converted into an impermeable for the pressure in the control volume switching position.

In the simplest embodiment, the first solenoid valve is a 2/2-way valve and only responsible for the connection of the control volume with the source of the pressure medium. The second solenoid valve is then also a 2/2-way valve and only for the control of the outlet of the

Control volume responsible. The use of more complex valves, and in particular a series connection, which is responsible both for the connection of the control volume with the source of the pressure medium and for the control of the outlet from the control volume, allows a space-saving arrangement of the solenoid valves, but also an integration of additional functions , For example, different control inputs on different devices can be controlled independently, or there can be more

Compressed air paths are switched, which provide detached functions of the control volume. However, then only driving means for two valves are necessary.

Advantageously, the solenoid valves are designed as monostable valves. Then they are automatically returned to a defined position in case of failure of the electrical supply. Starting from this defined position, for example, pneumatic back-up circuits can be planned.

It was recognized that in a scarf invention tanordnung the

Solenoid valves must be subjected to power only for much shorter times than in the prior art: The control volume has been filled by the first solenoid valve and / or by the series connection with the pressure medium and it has only outlets, which are controlled by solenoid valves may be through the first solenoid valve and / or through the

Connected in series switching state can be conserved as long as desired. The valves must therefore be energized only when the switching state must be changed. With such short-term loads, a significantly greater bandwidth of supply voltages is permissible given the internal resistance of the solenoid valve. This higher bandwidth can be used to design the circuitry as a whole for lower supply voltages. Furthermore, energy is saved when the solenoid valves only have to be pressed briefly.

According to the prior art was particularly in

Compressed air treatment plants the duty cycle of the solenoid valves not determinable in advance. For example, it depended on the ones to be followed

Pressure conditions in the reservoirs and the current compressed air consumption from. Some of the conditions on which the duty cycle of the solenoid valves depend can potentially permanently stop. In the prior art, such situations have caused solenoid valves to be constantly energized. Since many compressed air consumers, such as brake systems, must be available at all times, prohibits the technical enforcement of a maximum duty cycle of the solenoid valves in many cases. According to the invention, it is now automatically ensured that the solenoid valves must be energized only for a small fraction of the operating time of the scarf tanordnung. For such short

On-time a solenoid valve can withstand a multiple of this

Continuous load permissible current.

This also has the consequence that for the same tax task significantly cheaper solenoid valves used and thus costs in the realization of

Compressed air systems can be saved. For example, for use in Antiblockiersy stars (ABS) mature, cheap solenoid valves are available in large quantities. However, they are designed for short-term use and could therefore not be used in compressed air supply systems so far. By limiting the duty cycle by the interconnection according to the invention, these valves can now be used for example in the air dryer assembly of a compressed air treatment plant.

Compressed air is also particularly advantageous as a pressure medium when the

Scarf tanordnung is not installed in a compressed air treatment plant. On the one hand, compressed air is available everywhere and, on the other hand, does not have to be returned to a reservoir after use.

If the control volume has a throttled outlet for the pressure medium, which is not blocked by a further solenoid valve, the device by single activation of the first solenoid valve and / or by the

Connected in series for a defined period of time in the second operating state: By the first solenoid valve and / or by the

Connected in series pressure of the pressure medium escapes slowly through the throttled outlet. If the pressure falls below a critical threshold, the device automatically switches from the second operating state to the first one

Operating status back. It is advantageous between the first solenoid valve and the control volume, and / or between the series connection of the first

Solenoid valve with the second solenoid valve and the control volume, arranged in the direction of the control volume pressure relief valve. Then, the first solenoid valve and / or the series connection can be relieved of pressure without the set switching state is lost.

In a particularly advantageous embodiment of the invention, the first

Solenoid valve, and / or its series connection with the second

Solenoid valve, connected in the regeneration path of a compressed air supply system. The solenoid valve or the series connection can then be in the open state, a return flow of compressed air, which from the through the System supplied by at least one facility to

Compressed air treatment leads. This device may in particular be an air dryer. The regeneration path can, for example, bridge a check valve, which otherwise allows air flow only from the air dryer into the supplied area and not vice versa. The solenoid valve or the

Series connection switches in this arrangement not only the valve to be controlled, but at the same time ensures during its duty cycle for a regeneration of the air dryer with dried compressed air. For this purpose, in a further particularly advantageous embodiment of the invention, the switchable device comprises a in the compressed air supply system promoting compressor and / or a vent valve for the volume in which promotes the compressor. In this way it can be avoided that the

Backflow through the regeneration path and through the device for

Compressed air treatment is hindered by a built-up by the compressor backpressure. After the first solenoid valve, or his

Connected in series with the second solenoid valve is turned off, the control air is included in the control volume before the control inputs of the compressor and / or the vent valve. The compressor can therefore be prevented for as long as possible to promote compressed air in the compressed air supply system, without the constant need for a solenoid valve must be active. Conversely, no permanent activation of a solenoid valve is necessary when at high

Compressed air consumption constantly compressed air must be conveyed into the system. A solenoid valve must be active only briefly, if the promotion of compressed air to be switched on or off or if a regeneration of the device for

Compressed air preparation is necessary. These regeneration periods are also in the

Compared to the total operating time of scarf tanordnung very short.

The compressed air supply system is advantageously designed so that the compressor promotes compressed air into the system during a maximum of 50% of the total operating time and the device for compressed air treatment during a maximum of 10% of

Total operating time is regenerated.

If the control volume has a leak, the delivery of the compressed air is switched on again as soon as the pressure in the control volume has fallen below a certain level. However, means for refilling pressure medium in the are advantageous

Control volume for securing a pressure enclosed in the control volume provided. These means may be, for example, in a control of the first solenoid valve or its series connection with the second solenoid valve, which in the pressurized state of the control volume of this first

Open the solenoid valve or the series connection in a cyclically timed manner, so that any pressure fluid escaped by leaks from the control volume is replaced. But it can also be provided a monitoring of the pressure in the control volume, which initiates refilling only if this pressure has dropped unintentionally.

This embodiment is particularly advantageous when the switching arrangement is used to control an electropneumatic parking brake. Such a parking brake is usually designed as a spring-loaded brake, i. It is applied by a spring force and released by applying the spring brake cylinder with a release pressure. The piston in this brake cylinder, at

Actuation of the release pressure releases the brake is then the pneumatic control input of the spring brake, and the brake cylinder is the

Control volume.

In a further particularly advantageous embodiment of the invention, a fluid-actuated valve is provided, which has an outlet for the

Pressure fluid from the control volume opens when the pressure at at least one other location in the scarf tanordnung a predetermined value or

below. This can ensure that in case of failure of electrical supply, the switchable device is switched back from the second operating state to the first operating state. If the switching arrangement is installed, for example, in a compressed air supply system and controls the control volume of the compressor and / or a venting valve for the volume in which the compressor, the shading is preferably selected so that the compressor at normal pressure control volume normal air in the

Compressed air supply system promotes. If the control volume through the first solenoid valve, or by its series connection with the second

Solenoid valve, filled with compressed air, the promotion of compressed air is suppressed. So that important compressed air consumers, such as the brake system, even in case of failure of the electrical supply continue to receive compressed air, monitors the control input of the pressure-medium valve advantageously a location in the supplied area of the compressed air supply system. For this purpose, for example, the prevailing at this location pressure can be applied via the control input against the action of the valve spring. There is sufficient supply in the supplied area

Pressure, the pressure-actuable valve is thereby held in the closed position, and the control air remains trapped in the control volume. If the pressure in the supplied area drops, the spring force predominates and switches this

pressure medium actuated valve in the open position. The control volume is vented and the supply of compressed air to the supplied area is resumed.

Advantageously, the closing pressure of the pressure-medium valve is lower than the pressure, from which the delivery of the compressor is reactivated when the electrical supply is functioning. The pneumatic venting of the

Control volume is then a pure back-up for failures of the electrical

Supply, but does not pre-vent the control volume via the second solenoid valve when the electrical supply is functioning. Advantageously, the vent valve has a second control input which, when pressurized above a predetermined value, opens the vent valve and which is connected to the volume into which the compressor delivers or to the area supplied by the compressed air supply system. Then it fulfills a dual function and not only allows the interruption of the

Compressed air delivery by driving the first solenoid valve or the

Series connection of the first solenoid valve with the second solenoid valve, but also an automatic safeguard against the construction of a dangerous overpressure, which also works in the de-energized state.

In a particularly advantageous embodiment of the invention is the

Connected in series from the first solenoid valve and the second

Solenoid valve designed such that

• the first solenoid valve and the second solenoid valve each provide at least the functionality of a 3/2-way valve;

• The second solenoid valve connects its output connected to the input of the first solenoid valve in a first switching position with a vent and in a second switching position with the source of the pressure medium; and

· The first solenoid valve has at least two outputs, which are connected to two independent control volumes for the control of different control inputs, wherein the first solenoid valve in each switching position connects at least one control volume to the input and shuts off at least a second control volume.

In this embodiment, the second solenoid valve in its first switching position, one of the control volumes is vented. Which control volume is vented is selected by switching the first solenoid valve. On the other hand, if the second solenoid valve is in its second switching position, one of the control volumes is pressurized by the pressure medium source. which

Control volume is pressurized, by switching the first

Solenoid valve selected.

Optionally, a regeneration path for the regeneration of

Feed compressed air preparation device of a compressed air supply system through at least one control volume. In this way it is ensured that this control volume always receives compressed air when the regeneration path is open. The control volume can for example control a vent valve, so that whenever the regeneration path is opened, the air flowing back through the air dryer and moisture laden air can flow through this vent valve to the outside. In a further advantageous embodiment of the invention, the output of the second solenoid valve with that control volume which is shut off in the de-energized state of the first solenoid valve of this first solenoid valve, connected via a first solenoid valve bypassing in the opening in the direction of this control pressure relief valve is arranged. Then, this control volume, regardless of whether the first solenoid valve is energized, be filled by energizing the second solenoid valve with pressure medium. If both solenoid valves are energized, both control volumes can be filled simultaneously with pressure medium. If a pressure-medium-actuated valve is provided which opens an outlet for the pressure medium from the control volume connected twice (via the first solenoid valve and via the first solenoid valve bridging pressure relief valve) depending on the pressure at at least one other location in the switching arrangement, this outlet is at a Failure of the electrical supply also act simultaneously on the second control volume, since the first solenoid valve in his first switching position falls back and thus releases a path from the second control volume to the connection between the two solenoid valves.

In a further particularly advantageous embodiment of the invention, the series connection of the first solenoid valve and the second

Solenoid valve designed such that

• The first solenoid valve in the energized state its input with at least one control volume connects and in the de-energized state part of a regeneration path for the regeneration of a compressed air treatment device of a

Comprises compressed air supply system, wherein the solenoid valve interrupts this part of the regeneration path in the energized state. By energizing both solenoid valves, the control volume can then be pressurized, for example, to shut down a compressor and / or to open a vent valve. Thereafter, a regeneration of

Compressed air treatment device (air dryer) are triggered by the first solenoid valve is de-energized. For the duration of the regeneration, only the second solenoid valve must remain energized. Will this be the end of the

Disconnected from regeneration, the control volume can be vented by subsequent brief energization of the first solenoid valve and the ground state of the scarf tanordnung be restored. Special description part

The subject matter of the invention will be explained below with reference to figures, without the subject matter of the invention being limited thereby.

It is shown:

Figure 1 compressed air supply system with an embodiment of

switching arrangement according to the invention; and

FIG. 2 realization of a pneumatic back-up for the one shown in FIG

Switching arrangement.

Extension of the scarf tanordnung shown in Figure 2 to additional pressure sensors.

Function integration by connecting two 3/2-way valves in series.

Extension of the embodiment shown in Figure 4 by simultaneous filling of the control volumes 3a and 3b.

Realization of the same functionality as in FIG. 1 with a series connection of two solenoid valves 4 and 6.

Figure 1 shows a compressed air supply system S, in which a pneumatic scarf tanordnung invention is integrated. A compressor 1 delivers into a volume V to which an air dryer cartridge 9 connects. The air dryer cartridge 9 dries the compressed air supplied by the compressor. Via a check valve 5a the dried compressed air enters the area 5 supplied by the compressed air supply system S.

The promotion of compressed air is controlled by an electronic control unit 14. To interrupt the promotion, a solenoid valve 4 is activated. This introduces compressed air from the supplied area 5 via a check valve 8 in

Control volume 3. This control volume 3 is both with a pneumatic control input la of the compressor 1 and with a pneumatic

Control input 2a of a vent valve 2 connected, which vents the volume V, in which the compressor 1, via an outlet E vented. Is located

Control pressure in volume 3, the compressor 1 is stopped, and the volume V is vented to the outlet E out. While the solenoid valve 4 is activated, also dry compressed air from the supplied area 5 to a

Regeneration path (A-B-C-D-E) in the rearward direction through the air dryer 9 passed. This dry compressed air is released via a throttle 10. she leads

Moisture from the air dryer 9 from and transported through the valve 2 and the outlet E from the system. If the solenoid valve 4 is closed again by interrupting its energization, the regeneration path is restored

interrupted. Nevertheless, the control air is stored in the control volume 3. The compressor 1 therefore remains switched off and the volume V continues to be vented through the venting valve 2 and the outlet E. Only when the control volume 3 is vented with the second solenoid valve 6, the control inputs la of the compressor 1 and 2a of the vent valve 2 are depressurized. The valve 2 returns to the closed position and the compressor starts again. The promotion of compressed air in the supplied area 5 is resumed.

The check valve 11 ensures that the control volume 3 is pressurized only via the solenoid valve 4 and not over the part (CB) of the regeneration path. The vent valve 2 has a second pneumatic control input 2b. This is connected to the volume V, in which the compressor 1 promotes. If too much pressure builds up there, this will be reduced by the outlet E. In Figures 1 to 3 are in addition to the electrical control lines for

Solenoid valves 4 and 6, the lines belonging to the control volume 3 lines drawn as dashed lines. The drawn as a dashed line rectangle encloses all elements that are involved in the installation of the invention

Compressed air supply system S in the between the compressor 1 and the

Compressed air consumer connected assembly "air dryer" are summarized.

FIG. 2 is supplemented with respect to FIG. 1 by a back-up system which maintains emergency operation in the event of a power failure. A pressure medium operable valve 12 is connected between the control volume 3 and an outlet 13. By tapped from the point A in the region 5 supplied by the system S pressure, the valve 12 is held against the force of the valve spring in the closed position. If this pressure falls below a predetermined value, this is a sign that in area 5 more compressed air is needed. In this case, it should be ensured that even in case of failure of the electrical supply, the promotion of

Compressed air is activated. For this purpose, the valve 12 is switched at decreasing control pressure at point A by the force of the valve spring in the open position and vent the control volume 3. Thus, the vent valve 2 is closed, and the compressor 1 is started. A safeguard against the build-up of a dangerous overpressure is still given, since in such a case the

Control input 2b, the vent valve 2 switches to the through position.

The control line to the control input of the valve 12 is operatively connected to the electrical control lines of the solenoid valves 4 and 6 to the effect that the valve 12 is a back-up for the failure of these lines. It also works together functionally with the control volume 3 by this if necessary. is vented. To illustrate this relationship, it is shown in dashed lines in Figures 2 and 3.

FIG. 3 is supplemented with respect to FIG. 2 to the effect that electronic pressure sensors 15a and 15b are additionally provided. The sensor 15a monitors the pressure in the region 5 supplied by the compressed air supply system S. The pressure sensor 15b monitors the pressure in the control volume 3. The signals of the pressure sensors 15a and 15b are fed to the central control unit 14 via control lines, which are not shown for reasons of clarity. Furthermore, in this embodiment of the invention, the first solenoid valve 4 is formed differently. In its closed position, its work is depressurized. This causes the pressure drop at the check valve 11 is maximum and this valve closes very tight. If the control volume 3 pressurized, that works too

Pressure drop at the check valve 8 maximum, so that is ensured for a particularly safe enclosure of the control air.

FIG. 4 shows a further embodiment of the invention. It differs from the embodiment shown in Figure 1 in that a series connection of two 3/2-way valves 4 and 6 is responsible for both the loading and for the venting of two independent control volumes 3a and 3b. In this case, the pressure in the control volume 3 a controls the control input 1 a of the compressor 1. The pressure in the control volume 3b controls the pneumatic control input 2a of the venting valve 2. The division into two independent control volumes 3a and 3b enriches the compressed air supply system by two additional functions. On the one hand, the compressor 1 can be switched off by pressurizing the control volume 3a without the venting valve 2 being opened at the same time and the pressure already built up by the compressor 1 in the volume V being lost ("supply line closing"), but on the other hand it is also possible , by Druckbeauf suppression of the control volume 3b to open the vent valve 2, while the compressor 1 remains turned on. The compressor 1 then promotes through the vent E to the outside, the extracted air waste heat of the

Compresses compressor 1 and so the air path heats ("pneumatic heating"). Since these airways are in front of the air dryer 9 and the air can still be humid here, this heating can be a freezing of the airways are prevented.

The switching state of the second solenoid valve 6 decides whether a

Control volume is pressurized or vented. On which

Control volume (3a or 3b) acts this measure respectively is determined by the

Switching state of the first solenoid valve 4 decided.

At the same time, the regeneration path A-B-C-D-E leads through the control volume 3b. By energizing the solenoid valve 6 thus this regeneration path and the vent valve 2 can be opened simultaneously. In this case, the user has a free choice as to whether the compressor 1 is switched off beforehand by enclosing a pressure in the control volume 3a or can be conveyed to the outside for the purpose of pneumatically heating the air passages. This can be made dependent on the outside temperature, for example.

The embodiment shown in Figure 5 is compared to the embodiment of Figure 4 to a bypass line 15 with a check valve 15a extended, which bridges starting from the connection between the two solenoid valves 4 and 6, the first solenoid valve 4 and into the control volume 3a. The check valve 15a opens in the direction of this control volume 3a.

An energization of the second solenoid valve 6 now basically causes the control volume 3a is pressurized. If at the same time the first solenoid valve 4 is energized, both control volumes 3a and 3b are pressurized simultaneously. The pressure in the control volume 3a can be included by the first Solenoid valve 4 is de-energized. The pressure in the control volume 3b, however, remains only as long as the second solenoid valve 6 is energized, since it can escape via the check valve 11 and the throttle 10. The embodiment shown in Figure 6 realized by the

Series connection of the first solenoid valve 4 with the second solenoid valve 6 substantially the same functionality, which also provides the embodiment shown in Figure 1. The control input la of the compressor 1 and the control input 2a of the vent valve 2 are connected to the same control volume 3, which can be acted upon by brief simultaneous energization of the two solenoid valves 4 and 6 with pressure. Will be the first

Solenoid valve 4 is de-energized, the second solenoid valve 6, however, still energized, the regeneration path is opened and the air dryer 9 rinsed. The advantage over the embodiment shown in Figure 1 is that the series connection is more compact build and that at the same time

Check valve 8 can be saved from Figure 1.

LIST OF REFERENCE NUMBERS

1 compressor

la Pneumatic control input of the compressor

2 bleed valve

2a, 2b Pneumatic control inputs of the venting valve 2

3, 3a, 3b control volumes

4 First solenoid valve

5 Area supplied by the compressed air supply system S

5a In the area 5 leading non-return valve

6 Second solenoid valve

7 outlet of the second solenoid valve 6

8 In the control volume 3 leading check valve 9 air dryer cartridge

10 throttle in the regeneration path (A, B, C, D, E)

11 Check valve in the regeneration path (A, B, C, D, E)

12 Pressure-actuated valve as a pneumatic back-up

13 outlet of the valve 12

14 electronic control unit

15 bypass line

15 a check valve in the bypass line 15th

A, B, C, D, E points along the regeneration path

E outlet of the bleeder valve 2

S Compressed air supply system

V volume in which the compressor 1 promotes

Claims

Expectations

Pneumatic or hydraulic switching arrangement, comprising at least one device (1, 2), which can be switched from a first operating state to a second operating state by pressurizing a pneumatic or hydraulic control input (la, 2a),

characterized in that

A control volume (3, 3a, 3b) for a pressure medium is connected upstream of the control input (la, 2a), this control volume (3, 3a, 3b)

• through a first solenoid valve (4) and/or through a

Series connection of this first solenoid valve

(4) with a second solenoid valve (6) with a source (1,

5) can be connected to the pressure medium and

• at least one through a second solenoid valve (6) and/or through the series connection of the first solenoid valve (4) with the second solenoid valve

(6) controlled outlet (7) and/or at least one throttled outlet

(7) for the pressure medium,

• where the first solenoid valve (4) and/or its

Series connection with the second solenoid valve (6) into one that is impermeable to the pressure in the control volume (3, 3a, 3b).

Switch position can be transferred.

Switching arrangement according to claim 1, characterized in that between the first solenoid valve (4) and the control volume (3, 3a, 3b), and/or between the series connection of the first solenoid valve (4) with the second solenoid valve (6) and the control volume (3, 3a, 3b), a pressure safety valve that opens in the direction of the control volume (3, 3a, 3b).

(8) is arranged. Switching arrangement according to one of claims 1 to 2, characterized

characterized in that the first solenoid valve (4) and/or the

Series connection of the first solenoid valve (4) with the second solenoid valve (6), in the regeneration path (A-B-C-D-E).

Compressed air supply system (S) is switched so that the first

Solenoid valve (4) or the series connection in the open state allows a return flow of compressed air, which flows from the area (5) supplied by the system (S) through at least one device (9).

Compressed air preparation leads.

Switching arrangement according to claim 3, characterized in that the switchable device comprises a compressor (1) which delivers into the compressed air supply system (S) and/or a vent valve (2) for the volume (V) into which the compressor (1) delivers .

Switching arrangement according to claim 4, characterized in that

Venting valve (2) has a second control input (2b), which opens the venting valve (2) when pressure is applied above a predetermined value and with the volume (V) into which the compressor (1) delivers, or with that through the compressed air supply system ( S) supplied area (5) is connected.

Switching arrangement according to one of claims 1 to 5, characterized

characterized in that means for refilling pressure medium into the control volume (3, 3a, 3b) are provided to ensure a pressure enclosed in the control volume (3, 3a, 3b). Switching arrangement according to one of claims 1 to 6, characterized

characterized in that a pressure medium-operated valve is provided, which opens an outlet (13) for the pressure medium from the control volume (3, 3a, 3b) when the pressure at at least one other location (A) in the switching arrangement exceeds a predetermined value. or falls below.

Switching arrangement according to one of claims 1 to 7, characterized

characterized in that the solenoid valves (4, 6) are designed as monostable valves.

9. Switching arrangement according to one of claims 1 to 8, characterized by a series connection of the first solenoid valve (4) with the second solenoid valve (6) in such a way that

• the first solenoid valve (4) and the second solenoid valve (6) each provide at least the functionality of a 3/2-way valve;

• the second solenoid valve (6) is connected to the inlet of the first

Solenoid valve (4) connected output in a first switching position with a vent and in a second switching position with the source (1, 5) for the pressure medium;

The first solenoid valve (4) has at least two outputs which are connected to two independent control volumes (3a, 3b) for controlling different control inputs (la, 2a), the first solenoid valve (4) having at least one control volume ( 3a, 3b) connects to the input and blocks at least one second control volume (3a, 3b).

10. Switching arrangement according to one of claims 1 to 9, characterized

characterized that a regeneration path (A-B-C-D-E) for the

Regeneration of a compressed air processing device (9).

Compressed air supply system (S) through at least one control volume (3, 3a,

3b) leads.

11. Switching arrangement according to one of claims 9 to 10, characterized

characterized in that the output of the second solenoid valve (6) with that control volume (3a, 3b) which is shut off by this first solenoid valve (4) when the first solenoid valve (4) is de-energized, via a line bypassing the first solenoid valve (4). is connected, in which an opening towards this control volume (3a, 3b).

Pressure safety valve is arranged.

12. Switching arrangement according to one of claims 1 to 8, characterized by a series connection of the first solenoid valve (4) with the second solenoid valve (6) in such a way that

• the second solenoid valve (6) is connected to the inlet of the first

• the first solenoid valve (4) in the energized state connects its input to at least one control volume (3, 3a, 3b) and in the de-energized state a part of a regeneration path (A-B-C-D-E) for the regeneration of a compressed air processing device (9) of a compressed air supply system (S) forms, with the solenoid valve (4) interrupting this part of the regeneration path (A-B-C-D-E) when energized.