Compressed Air Maintenance Unit and Consumer Control Device Equipped with the Same

Abstract

A compressed air conditioning apparatus (2) and a load control device (1) equipped therewith are proposed, the compressed air conditioning apparatus (2) comprising a switch-on valve (14) with 3/3-valve functionality. By means of the switch-on valve (14), an outlet passage (22) leading to a load device (A) can, among other aspects, be optionally supplied with compressed air or disconnected from the compressed air supply. By means of a pressure sensor (24) and/or a flow sensor (25), actual pressure and/or flow data can be recorded and compared to reference data previously stored in a teaching mode. As a function of the comparison result, an electric diagnostic signal can be generated, offering, among other aspects, the opportunity for monitoring leakage from the load device (A) or excessive air consumption.

Description

The Invention relates to a compressed air conditioning apparatus comprising the following components:

• • an electrically actuated switch-on valve which comprises a feed inlet connectable to a compressed air source, a vent outlet connected to the atmosphere and an operating outlet and which can be switched into a working position connecting the operating outlet to the feed inlet and into a venting position connecting the operating outlet to the vent outlet,
  • an apparatus outlet connectable to an external load device and connected to the operating outlet of the switch-on valve via an outlet passage,
  • a pressure sensor suitable for measuring the outlet pressure prevailing in the outlet passage and/or a flow sensor suitable for measuring the output flow prevailing in the outlet passage,
  • and an internal electronic control unit which is connected in terms of signalling technology to the switch-on valve and to the pressure sensor and/or the flow sensor and which can be operated in a monitoring mode.

The invention further relates to a load control device suitable for controlling a load device, which is equipped with at least one compressed air conditioning apparatus of the type referred to above and with an electronic control device connected or connectable thereto.

Prior art designed in the above sense is known from DE 19746179 C2. This publication describes a compressed air conditioning unit which is fluid-connectable to a load device to be supplied with compressed air. The compressed air conditioning unit is composed of a plurality of modules which can be lined up in any sequence or number. One module of the known compressed air conditioning unit is designed as a monitoring module which comprises an electronic central unit and can be connected to an external bus system via a suitable interface. The monitoring module may be fitted with indicating and control elements or may alternatively be provided with a diagnostic and control interface for an external indicating and control device. A pressure sensor for pressure detection is connected to the central unit in the monitoring module. A further module of the compressed air conditioning unit may be a flow meter module for measuring the air flow rate. Finally, the known compressed air conditioning unit comprises a switching valve module provided with a switch-on valve, by means of which the compressed air fed in at the inlet can either be let in or blocked. Switch-on valves frequently also have a three-way function, so that, if the compressed air is blocked, they adopt a venting position in which the operating outlet is connected to the atmosphere, so that the outlet passage adjoining the operating outlet including the load device connected thereto is vented.

From DE 102004005982 B3, a compressed air conditioning apparatus is known which is made up of a plurality of modules, which may for example include a switch-on valve, a flow meter, a control module or a monitoring module. Sensor devices for pressure or flow detection may also be provided.

DE 10355250 A1 describes a method and an associated device for leak detection in an operating device equipped with an operating cylinder. The device includes a pressure sensor detecting the pressure of the pressure fluid, a loss of pressure fluid being detected on the basis of pressure fluctuations. In addition, a flow sensor installed into the supply lines detects the flow rate of the flowing pressure fluid, wherein, on the basis of a physical equation, the measured pressure value and the measured flow rate are brought into a specific relationship to one another in order to determine any existing leakage on this basis.

From WO 95/19589 A1, the use of a monitoring device for monitoring cyclically operating systems is known.

Compressed air conditioning units of the type referred to above are generally fitted with switch-on valves having two possible switching positions. A first switching position is conceived as a working position and establishes a connection between the feed inlet and the operating outlet and thus a connected external load device. In the second switching position, the feed inlet is disconnected from the operating outlet. If the second switching position is a venting position, the outlet passage is simultaneously vented together with the external load device connected thereto. Other types of switch-on valves completely block the outlet passage in the second switching position, making venting impossible. The venting function, however, is an important aspect of the compressed air supply of any connected load device.

A disadvantage of compressed air conditioning apparatus of the present time, the switch-on valve of which has a venting position, lies in the fact that air is consumed unnecessarily while the connected external load device is inoperative. If the switch-on valve remains in the working position, compressed air is continuously pushed at high pressure into the outlet passage irrespective of the non-operation of the load device, and this air is lost owing to unavoidable leakage. If the switch-on valve is switched into the venting position, on the other hand, the outlet passage and the load device connected thereto are emptied completely, with the result that the emptied passage system has to be refilled completely when the load device is restarted. In terms of energy efficiency, such circumstances accompanying the start of external loads are no longer in keeping with the times.

The present invention is based on the problem of providing measures facilitating the energy-efficient operation of air-operated load devices.

To solve this problem, it is provided in a compressed air conditioning apparatus of the type referred to above

• • that the switch-on valve has a 3/3-valve functionality and can additionally be switched into a blocking position in which its operating outlet connected to the apparatus outlet is isolated both from the feed inlet and from the vent outlet,
  • that the internal electronic control unit can in the blocking position and/or in the working position be operated in a teaching mode as an alternative to the monitoring mode, in which teaching mode a time-dependent pressure drop of the outlet pressure can be determined in the blocking position and/or a time-dependent flow profile of the outlet flow rate can be determined in the working position and these values can be stored in the form of reference data in storage means of the internal electronic control unit,
  • that the internal electronic control unit comprises comparator means whereby actual data supplied by the pressure sensor and/or the flow sensor during the monitoring mode can be compared to the relevant reference data,
  • and that the internal electronic control unit comprises outputting means which can output a diagnostic signal as a function of the comparison result of the comparator means.

The problem is further solved in a load control device which comprises a compressed air conditioning apparatus of this design and an external electronic control device connected or connectable thereto.

The inventive idea includes that the compressed air conditioning apparatus may be equipped both with a pressure sensor and with a flow sensor or—depending on the type of monitoring required—with a pressure sensor or a flow sensor only.

The term “flow” is here used to represent in a simplified fashion inherently correct terms such as “volumetric flow rate”, “flow rate” or “throughput” and indicates a flow value per unit of time.

A special measure of the invention is the aspect that the switch-on valve having a three-way function is designed as a 3/3-way valve and can adopt three alternative switching positions. In this context, it is advantageous that, in addition to the working position provided as standard, a venting position or a blocking position can be selected in order to either discharge the compressed air present in the outlet passage and in the external load device connected thereto completely or to keep it as an enclosed volume during temporary interruptions in the operation of the external load device. Without losing the advantages of a venting facility, both an excessive leakage and the unnecessary emptying of the outlet-side passage system can therefore be avoided during a temporary stop of, for example, a machine acting as a load device. This allows for energy-efficient operation.

A further contribution to increased efficiency is provided by the internal electronic control unit, which can optionally be operated either in a teaching mode or in a monitoring mode. The latter facilitates the output of an electric diagnostic signal for general use if the internal pressure sensor and/or the flow sensor of the compressed air conditioning apparatus detect(s) pneumatic conditions which deviate from the values expected or tolerable in normal operation. Such deviating operating states may for example be leakage from of a malfunction of components of a connected external load device. Monitoring is made particularly effective by providing that the internal electronic control unit—in particular in combination with the initial start-up of a connected external load device—can be operated in a teaching mode for recording individual reference data for pressure and/or flow, which can in the subsequent operation of the system be used for comparison to actually measured data in a monitoring mode of the internal electronic control unit. The monitoring functionality of the compressed air conditioning apparatus can therefore be adapted to the respective application very flexibly.

Using the pressure sensor, it is in particular possible to monitor the drop in the outlet pressure in the blocking position of the switch-on valve and, if this pressure drops too fast, to output an alarm signal following a comparison with the taught reference data. This facilitates leakage monitoring in the external load device, which may for example be represented by a machine.

Using the data supplied by a flow sensor, conclusions can be drawn regarding an increased air consumption of the connected external load device in the working position of the switch-on valve, for example as overall information relating to a whole operating cycle of the load device or relating to specific sub-cycles of the operating cycle.

The compressed air conditioning apparatus is preferably designed as a self-supporting unit with all of its components being integrated, resulting in an extremely compact compressed air conditioning apparatus which can easily be integrated into existing pneumatic systems.

If the compressed air conditioning apparatus is equipped with a flow sensor which determines the flow rate on the basis of detected pressure values, in particular on the basis of detected pressure differentials, a pressure sensor belonging to the flow sensor can also be used as pressure sensor for the detection of the outlet pressure prevailing in the outlet passage. In this case, there is no need for a separate pressure sensor.

The compressed air conditioning apparatus is expediently directly provided with visual display means and/or with audible warning means which can be actuated on the basis of an electric diagnostic signal generated by the outputting means in order to indicate operating problems directly on site.

The compressed air conditioning apparatus is expediently designed such that the electric diagnostic signal it generates can be processed externally. For this purpose, the compressed air conditioning apparatus can be provided with at least one communication interface to which can be connected an external electronic control device which in particular acts as a host and/or an electronic data reader and/or at least one further external electronic device. There may for example be two communication interfaces of which one can be used for communication with the external electronic control device, while the other can be used as diagnostic interface for connection to the data reader. The respective communication interface is preferably of an electromechanical type, which facilitates a very secure signal transmission, in particular via an electric cable connectable thereto. At least one of the communication interfaces is preferably designed as a bus interface, which allows the connection of a bus leading to an external electronic control device; any bus standards can be used.

In an alternative embodiment, at least one communication interface is configured for wireless signal transmission, in particular for fault indication via a cellular radio system, and/or for any other wireless network connection.

In a particularly advantageous embodiment, the at least one communication interface is designed such that a bidirectional signal transmission is possible.

At least one communication interface can be designed for inputting and/or outputting binary and/or analogue signals. Such a communication interface is in particular provided in addition to a communication interface designed as a bus interface.

The switch-over commands for the switch-on valve are expediently supplied to the compressed air conditioning apparatus from the outside and come from the connected external electronic control device. In this case, the internal electronic control unit only has to act as a transmitter of switch-over signals without specifically processing the latter. This reduces the load on the at least one microprocessor of the internal electronic control unit.

For the activation and/or parameterisation of the teaching mode, the compressed air conditioning apparatus is expediently equipped with suitable inputting means. Such inputting means may for example comprise at least one key and/or at least one switch easily accessible on the outside of the housing of the compressed air conditioning apparatus. In addition or alternatively, facilities may be provided for purely electric teaching, for example via a special user interface or by means of an external electronic control device which generally communicates with the compressed air conditioning apparatus; for this purpose, the compressed air conditioning apparatus can be provided with at least one electric interface which may in particular be represented by the communication interface referred to above.

The current data required in the monitoring mode of the internal electronic control unit are expediently recorded at the same time interval as the reference data recorded in the teaching mode.

In the monitoring mode, the internal electronic control unit records the current data once or repeatedly, or repeatedly at regular intervals, depending on operating conditions.

In addition to mere operation monitoring, the electric diagnostic signal can be used to initiate specific, in particular safety-relevant, actions. The compressed air conditioning apparatus can for example be designed to initiate a switch-over action of the switch-on valve in response to the comparison result of the comparator means. A switching of the switch-on valve into the blocking position can for example be initiated if no significant flow is detected in the outlet passage for an extended period of time in the working position.

The invention is explained in greater detail below with reference to the accompanying drawing. The single FIGURE (FIG. 1) is a diagrammatic representation of a preferred structure of a load control device according to the invention, comprising an integrated compressed air conditioning apparatus according to the invention, which has a particularly expedient structure.

The load control device identified as a whole by the reference number 1 comprises as its main component a compressed air conditioning apparatus 2, preferably in the form of a self-supporting unit. This compressed air conditioning apparatus 2 can, if required, be combined with other conditioning modules, of which one is indicated by dot-dash lines at 3, to form a compressed air preparation device 4. The at least one further conditioning module may for example be a pressure control module, a filter module and/or an air drier module.

The compressed air conditioning apparatus 2 has an apparatus housing 5 which is illustrated as a frame for simplicity and which supports and/or encloses the further components of the compressed air conditioning apparatus 2.

On the outside of the apparatus housing 5, an apparatus inlet 6, an apparatus outlet 7 and a vent outlet 8 are provided. The apparatus inlet 6 is designed for connection to a compressed air source P via a fluid line identified as feed line 12. This compressed air source P is shown in a state in which it is connected to the apparatus inlet 6.

The apparatus outlet 7 is designed for the connection of a fluid line identified as operating line 13, which leads to an external load device A. The drawing shows a state in which a load device A is connected to the apparatus outlet 7—for example a machine having several fluid-operated working components.

The vent outlet 8 communicates with the atmosphere R. For this purpose, a silencer not shown in detail is expediently connected to the vent outlet 8. Ducted air discharge by means of a connectable fluid line is also possible.

The compressed air conditioning apparatus 2 is provided with an electrically actuated multiway valve identified as “switch-on valve” 14 on the basis of its function. The switch-on valve 14 is expediently accommodated in the interior of the apparatus housing 5. It has a 3/3-functionality, i.e. three ways or ports and three possible switching positions. In the illustrated embodiment, it is implemented in the form of a single valve unit, but can also be implemented by the suitable interconnection of several valve units of lower functionality. The switch-on valve 14 is preferably an electro-pneumatically pilot-actuated valve, but it could also be designed as a directly electrically actuated valve.

The switch-on valve 14 of the illustrated embodiment has a first switching position conceived as central position, which is shown in the drawing. From this, it can be switched into a second or a third switching position by activating one of two electrically actuated valve drives 15a, 15b. The second and third switching positions are in each case maintained as long as the associated valve drive 15a, 15b is electrically activated. The electric valve drive 15a, 15b is in particular a solenoid device, but other electric drive means can be used as well.

The three ports of the switch-on valve 14 form a feed inlet 16, an operating outlet 17 and a vent outlet 18. The feed inlet 16 is permanently connected to the apparatus inlet 6 or directly represented thereby. The operating outlet 17 is permanently connected to the vent outlet 18 or directly represented thereby. The operating outlet 17 is connected to the apparatus outlet 7 via an internal outlet passage 22 of the compressed air conditioning apparatus 2. The outlet passage 22 expediently extends in the interior of the apparatus housing 5.

The switch-on valve 14 can adopt a blocking position which in the illustrated embodiment corresponds to the central position adopted in the non-actuated state. In this position, the operating outlet 17 is disconnected both from the feed inlet 16 and from the vent outlet 18. In this way, the outlet passage 18 is blocked and the fluid volume present therein as well as in the operating line 13 and the adjoining passage system of the load device A is locked in.

The two other possible switching positions of the switch-on valve 14 define a working position and a venting position. In the working position, the operating outlet 17 is connected to the feed inlet 16 while being disconnected from the vent outlet 18. In the venting position, the operating outlet 17 is connected to the vent outlet 18 while being disconnected from the feed inlet 16. In this way, the outlet passage 22 and the connected load device A are supplied with compressed air from the compressed air source P in the working position of the switch-on valve 14 and vented to the atmosphere in the venting position.

While the connected load device A is in operation, the switch-on valve 14 is held in the working position. During this time, the load device A completes a preset operating cycle once or periodically. This operating cycle is controlled by an external electronic control device which communicates in a manner not shown in detail with the load device A in terms of control technology.

If the load device A is not to operate for an extended period of time, for example at the weekend, the switch-on valve 14 can be switched into the venting position, so that the load device A is vented and no hazardous situations can develop.

If the load device A is inoperative for a short time only, the switch-off valve 14 can be positioned in the blocking position. In this way, the air volume present in the load device A is maintained and is available for renewed operation. There is therefore no need for again refilling the load device A completely with compressed air.

The compressed air conditioning apparatus 2 is provided with a pressure sensor 24 and a flow sensor 25. Both of the sensors 24, 25 are expediently accommodated in the interior of the apparatus housing 5. In addition, both of the sensors 24, 25 communicate with the outlet passage 22; in the illustrated embodiment, the pressure sensor 24 is connected to the outlet passage 22, while the flow sensor 25 is installed into the run of the outlet passage 22.

The pressure sensor 24 is capable of measuring the pressure prevailing in the outlet passage 22, this pressure being referred to as outlet pressure in further explanations. The flow sensor 25 is capable of determining the current flow rate of the compressed air flowing through the outlet passage 22, i.e. the flow of said compressed air. This measured flow will be referred to as outlet flow in further explanations.

If the measuring principle of the flow sensor 25 is based on pressure detection, a pressure sensor forming part of the flow sensor 25 can take over the function of the above pressure sensor 24, so that there is no need for an autonomous pressure sensor 24.

The compressed air conditioning apparatus 2 comprises an internal electronic control unit 26, which is preferably accommodated in the interior of the apparatus housing 5 and which is equipped with at least one microprocessor or microcontroller. To simplify matters, this will be referred to as “internal control unit 26” in further explanations.

In tennis of signal technology, the internal control unit 26 is connected to the valve drives 15a, 15b of the switch-on valve 4, to the pressure sensor 24 and to the flow sensor 25 by internal electric signal lines 27 of the compressed air conditioning apparatus 2. The internal control unit 26 can receive electric pressure values and flow values from the pressure sensor 24 and the flow sensor 25 respectively and output electric actuating signals to the switch-on valve 14.

The compressed air conditioning apparatus 2 is provided with an electric interface which is identified as first communication interface 28 in further explanations for better differentiation and which allows a signalling communication between the internal control unit 26 and the external electronic control device 23. The first communication interface 28 is in particular located on an outside of the apparatus housing 5 and expediently connected to the internal control unit 26 via internal electric conductors 32. The first communication interface 28 is preferably electro-mechanical in design and in particular designed as a plug-in connection device, so that an external signal cable 33, which is indicated diagrammatically only and which provides a connection to the external electronic control device 23, can be connected, in particular releasably.

As an alternative, the first communication interface 28 can be designed as a wireless interface for communication with the external electronic control device 23, in particular by way of radio signals.

The first communication interface 28 is preferably a bus interface which is capable of transmitting serial bus signals between the internal control unit 26 and the external electronic control device 23. Like the internal electric conductors 32, the external signal cable 33 can be implemented in the form of a serial bus system.

The internal control unit 26 comprises electronic storage means 34, comparator means 35 and outputting means 36. In the storage means 34, pressure values of the outlet pressure measured by the pressure sensor 24 and flow values of the outlet flow measured by the flow sensor 25 can be stored as reference data and preferably as actual values as well. The comparator means 35 are capable of comparing stored reference data to actual values which are in particular also buffered or else measured directly. The outputting means 36 are capable of outputting an electric diagnostic signal as a function of the comparison result determined by the comparator means 35.

The outputting means 36 of the internal control unit 26 preferably output the electric diagnostic signal to the first communication interface 28, from where it can be transmitted to the external electronic control device 23 for further processing as required.

The electric diagnostic signal can also be transmitted to visual display means 37 of the compressed air conditioning apparatus 2 for visualisation in a preferred way.

It is further possible to provide the compressed air conditioning apparatus 2 with audible warning means 38 as indicated by broken lines, for example with a buzzer, for outputting an audible warning signal on site on receipt of a corresponding diagnostic signal.

The internal control unit 26 can be operated in a monitoring mode in which it can receive and process measurement signals from the pressure sensor 24 and/or from the flow sensor 25 as actual data. In this way, the internal control unit 26 receives time-dependent current values of the outlet pressure and/or outlet flow as actual data. The internal control unit 26 can therefore be designed for outputting these actual data at the first communication interface 28 and/or at the visual display means 37 either electrically or visually.

In an advantageous way, the internal control unit 26 can, as an alternative to the monitoring mode, be operated in a teaching mode. Within this teaching mode, the internal control unit 26 can take up the reference data mentioned above and store them in the storage means 34 for further processing.

The compressed air conditioning apparatus 2 is expediently provided with inputting means 42 for activating the teaching mode if required. It may also be provided that the system can switch between the teaching mode and the monitoring mode as required by way of these inputting means 42. The internal control unit 26 is preferably equipped with an internal control programme which initiates an automatic switch-over to the monitoring mode as soon as the teaching phase is completed.

The teaching mode can expediently be activated both in the blocking position and in the working position of the switch-on valve 14. If the teaching mode is active in the blocking position, a time-dependent pressure drop of the outlet pressure prevailing in the outlet passage is recorded and stored as reference data 43 in the storage means 34. This may for example happen in response to pressing or activating a key or switch 42a of the inputting means 42 twice at any time interval preferred. The internal control unit 26 then records the pressure drop of the outlet pressure over time and forms a reference curve 43a which is represented by a straight line in the illustrated embodiment. The shape of this curve does, however, not affect any subsequent evaluation, because only the absolute value of the pressure drop (p1-p2) in the measured time interval (t2-t1) is relevant.

By operating in the teaching mode in the working position of the switch-on valve 14, a time-dependent flow profile Q(t) of the outlet pressure in the outlet passage as indicated by the reference number 44a can be determined and likewise stored in the storage means 34 of the internal control unit 26 in the form of second reference data 44. This happens during the operation of the connected load device A, and the flow profile 44a representing the second reference data 44 preferably covers the time of a whole working cycle of the load device A. The second reference data 44 can therefore be envisaged as a curve which represents the current outlet flow at any point in time during a typical working cycle.

In the subsequent normal operation of the load control device 1, the internal control unit 26 operating in the monitoring mode can generate an electric diagnostic signal which indicates the energetic situation of the connected load device A from a comparison between the measured actual data and the first or second reference data 43, 44.

The compressed air conditioning apparatus 2 in particular offers the opportunity for leakage monitoring in the blocking position of the switch-on valve 14. For this purpose, actual data delivered by the pressure sensor 24 in the blocking position of the switch-on valve 14 are recorded by the internal control unit 26 and compared to the first reference data 43 recorded and stored in the teaching mode. The measuring interval for recording the actual data is as long as that used for recording the first reference data 43, and this arrangement is monitored and controlled by a control programme in the internal control unit 26. If possible, the actual pressure should be measured at an outlet value of the outlet pressure which is at least approximately identical to that used in the reference pressure measurement, which is likewise monitored by the internal control unit 26. This ensures that the data to be compared can be assigned to one and the same operating state.

Via the outputting means 36, the internal control unit 26 then for example initiates the output of a diagnostic signal if the pressure drop of the outlet pressure determined in the monitoring mode falls below the reference value recorded in the teaching mode by a preset tolerance value.

The measurement of the actual data can be coupled to the switch-over process of the switch-on valve 14. The actual data can for example be recorded simultaneously with the outputting of a switch-over signal from the internal control unit 26 to the switch-on valve 14, or else delayed by a preset period of time.

When monitoring the outlet flow, the outputting of a switch-over signal for the switch-on valve 14 by the internal control unit 26 can likewise be used as an initiator for recording actual flow data.

Like in the monitoring of the outlet pressure, actual data can be recorded once only or repeatedly when monitoring the outlet flow, and in the repeated recording of actual data, regular time intervals can be used in particular.

Alternatively or in addition, the compressed air conditioning apparatus 2 preferably offers the opportunity of basing the recording of the actual data on a trigger signal supplied by the connected electronic control device 23, which trigger signal acts as an initiator. This trigger function of the external electronic control device 23 is particularly advantageous in flow monitoring, because it offers the possibility of monitoring the operating cycle of the load device A not only as a whole, but also of monitoring one or more sub-cycles of the overall operating cycle individually.

Flow is monitored in the working position of the switch-on valve 14. In this working position, compressed air normally flows from the compressed air source P to the load device A and there actuates one or more working components of the load device A which are activated by fluid power. One or more of these working components may for example be pneumatic drives. By comparing the actual outlet flow detected in the monitoring mode to the associated second reference data 44, it is made easy to monitor whether there is an increased air consumption during the operating cycle or during some of its phases or sub-cycles, which would indicate a malfunction of faulty working components.

In flow monitoring, too, the internal control unit 26 is in particular designed such that it outputs an electric diagnostic signal if detected actual data deviate by a preset tolerance value from the associated second reference data 44 recorded in the teaching mode. In the case of flow monitoring, the tolerance values are expediently stored in the internal control unit 26 in the form of tolerance bands 45a, 45b, which flank the characteristics 44a of the second reference data 44 from above and below.

The tolerance values to be taken into account when generating the diagnostic signal can preferably be input individually into the internal control unit 26. In this way, the used of the compressed air conditioning apparatus 2 can adapt the tolerance values and thus the outputting of the diagnostic signal individually to requirements. To input the tolerance values, the inputting means 42 referred to above can be used in particular, for example an arrangement of keys and/or switches 42 and/or—for electronic inputting—an electric interface which may for example be represented by the first communication interface 28 and to which a user interface and/or a personal computer (PC) can expediently be connected.

The tolerance values are expediently input in the teaching mode. The compressed air conditioning apparatus 2 may, however, alternatively offer the possibility of altering the tolerance values while the monitoring mode is running, in order to respond flexibly to changing operating conditions.

The teaching mode can expediently be parameterised individually using inputting means 42. This can be done at the compressed air conditioning apparatus 2 itself by activating keys and/or switches 42, or else by the external electronic control device 23 using the serial bus connection 33. This parameterisation can for example determine how often the actual data in the internal control unit 26 are evaluated during the relevant operating position of the switch-on valve 14. The changing of the tolerance values, for example the changing of the band width of the tolerance bands 45a, 45b, can also be subsumed under the tern of parameterisation.

In the illustrated embodiment, the compressed air conditioning apparatus 2 is provided with a further, second, communication interface 29 which can be used as a diagnostic interface and to which an electronic data reader 46 of the load control device 1 can in particular be connected at least intermittently. Such an electronic data reader 46 for example allows the reading of measured actual data, in particular in combination with the associated reference data, so that, for example in the context of flow monitoring, it is possible to verify either simultaneously or later at which point of the recorded reference profile an irregularity has occurred.

The internal control unit 26 is expediently designed or at least programmable in such a way that it can, as a function of the comparison result determined by the comparator means 35, trigger at least one further action in addition to the outputting of a diagnostic signal. In the illustrated embodiment, this additional function is the initiation of a switch-over action of the switch-on valve 14. This is for example switched from the working position into the blocking position if there is no or at least no significant outlet flow in the outlet passage 22 during a longer period of time, which can in particular be parameterised freely. Alternatively, it may be provided that the electric diagnostic signal directly causes a switch-over action of the switch-on valve 14.

While in the cases described above the output of a switch-over signal for the switch-on valve 14 can be initiated by the internal control unit 26, the switching position of the switch-on valve 14 is otherwise expediently determined exclusively by the external electronic control device 23, which for this purpose feeds the required switch-over signals into the internal control unit 26 via the first communication interface 28. The latter control unit exclusively acts as a transmitter of switch-over signals to the switch-on valve 14 without further processing the switch-over signals received from the external electronic control device 23 in any way. In this way, the load on the microprocessor in the internal control unit 26 is kept to a minimum.

The compressed air conditioning apparatus 2 can obviously be equipped with further electric interfaces of any kind. In this way, any number of switching outputs can be made available, analogue values can be output, or a facility can be provided for a configuration by means of a connectable personal computer. The preferably provided external electronic control device 23 is, as described above, expediently connected using serial signal transmission technology by means of a suitable bus which may, among other features, correspond to the so-called IO link standard.

One advantage of the compressed air conditioning apparatus 2 lies in its easy initial start-up. In principle, all that is required is the installation of the compressed air conditioning apparatus 2 into an existing pneumatic system, followed by a teaching phase. The apparatus is now ready for operation.

Further advantages of the arrangement described above lie in the fact that the connected load device A can be pneumatically blocked without venting its supply line 22, 13, so that no energy is wasted in periods of temporary non-operation. Nevertheless, the three-position functionality of the switch-on valve 14 provides a facility for venting the connected load device A if required. The pressure sensor 24 provided compares the pressure drop in the outlet passage 22 following its blocking to a taught reference curve and outputs a diagnostic signal if pressure drops too fast. This allows for the leakage monitoring of the load device A.

In normal operation, when the switch-on valve 14 is in the working position, the development of the flow value measured in the outlet passage 22 can be monitored in order once again to output a diagnostic signal of this deviates from the taught value. This allows for the consumption monitoring of the load device A.

If the compressed air conditioning apparatus 2 is implemented as a unit, it offers compact dimensions and combines a multitude of functions within a small space.

Finally, it should be pointed out that the compressed air conditioning apparatus 2 can be equipped with a reduced monitoring functionality by monitoring either the outlet pressure or the outlet flow only. In these cases, either the flow sensor 25 or the pressure sensor 24 can be omitted. However, the dual implementation of both monitoring measures in one and the same compressed air conditioning apparatus 2 is particularly advantageous, because it ensures that energy-relevant parameters are monitored in a particularly effective way.

Claims

1. A compressed air conditioning apparatus comprising:

an electrically actuated switch-on valve which comprises a feed inlet connectable to a compressed air source, a vent outlet connected to the atmosphere and an operating outlet and which can be switched into a working position connecting the operating outlet to the feed inlet and into a venting position connecting the operating outlet to the vent outlet;

an apparatus outlet connectable to an external load device and connected to the operating outlet of the switch-on valve via an outlet passage;

a pressure sensor suitable for measuring the outlet pressure prevailing in the outlet passage and/or a flow sensor suitable for measuring the outlet flow rate prevailing in the outlet passage; and

an internal electronic control unit which is connected in teens of signalling technology to the switch-on valve and to the pressure sensor and/or the flow sensor and which can be operated in a monitoring mode,

wherein the switch-on valve has a 3/3-valve functionality and can additionally be switched into a blocking position in which its operating outlet connected to the apparatus outlet (7) is isolated both from the feed inlet and from the vent outlet, and

wherein the internal electronic control unit can in the blocking position and/or in the working position be operated in a teaching mode as an alternative to the monitoring mode, in which teaching mode a time-dependent pressure drop of the outlet pressure can be determined in the blocking position and/or a time-dependent flow profile of the outlet flow rate can be determined in the working position and these values can be stored in the form of reference data in storage means of the internal electronic control unit, and

wherein the internal electronic control unit comprises comparator means whereby actual data supplied by the pressure sensor and/or the flow sensor during the monitoring mode can be compared to the relevant reference data, and

wherein the internal electronic control unit comprises outputting means which can output a diagnostic signal as a function of the comparison result of the comparator means.

2. A compressed air conditioning apparatus according to claim 1, wherein the apparatus is designed in the form of a unit.

3. A compressed air conditioning apparatus according to claim 1, further comprising visual display means and/or audible warning means which can be actuated on the basis of the electric diagnostic signal.

4. A compressed air conditioning apparatus according to claim 1, further comprising at least one communication interface connected to the internal electronic control unit to which can be connected an external electronic device for communication with the internal electronic control unit the at least one communication interface being designed as a bus interface.

5. A compressed air conditioning apparatus according to claim 4, wherein the at least one communication interface is of an electromechanical type and/or the at least one communication interface is designed for wireless signal transmission.

6. A compressed air conditioning apparatus according to claim 4, wherein the internal electronic control unit is designed for transmitting the electric diagnostic signal to at least one communication interface of the compressed air conditioning apparatus.

7. A compressed air conditioning apparatus according to claim 4, wherein the internal electronic control unit is designed for transmitting switch-over signals from an external electronic control device connected to a communication interface to the switch-on valve, in such a way that switch-over signals fed in via the communication interface can be transferred directly to the switch-on valve without any processing by the internal electronic control unit.

8. A compressed air conditioning apparatus according to claim 1, further comprising inputting means for activating and/or parameterising the teaching mode.

9. A compressed air conditioning apparatus according to claim 8, wherein the inputting means comprise at least one key and/or at least one switch and/or at least one electric interface.

10. A compressed air conditioning apparatus according to claim 1, wherein the actual data are recorded at a same time interval as the associated reference data.

11. A compressed air conditioning apparatus according to claim 1, wherein in the monitoring mode a switch-over signal intended for the switch-on valve and generated and output by the internal electronic control unit or a trigger signal delivered by an external electronic control device acts as an initiator for the recording of actual data.

12. A compressed air conditioning apparatus according to claim 11, wherein the actual data can be recorded by the internal electronic control unit starting with the output of a switch-over signal intended for the switch-on valve or thereafter with a preset time delay.

13. A compressed air conditioning apparatus according to claim 11, wherein actual data of the pressure sensor are recorded starting with or delayed after the output of a switch-over signal switching the switch-on valve into the blocking position, in order to allow leakage monitoring by way of a comparison with the associated reference data.

14. A compressed air conditioning apparatus according to claim 11, wherein actual data of the flow sensor are recorded once or repeatedly starting with or delayed after the output of a switch-over signal switching the switch-on valve into the working position, in order to allow air consumption monitoring by way of a comparison with the associated reference data.

15. A compressed air conditioning apparatus according to claim 1, wherein the internal electronic control unit tolerance values are or can be stored, which are taken into account when generating the electric diagnostic signal to be output, wherein the tolerance values can be present in the form of at least one tolerance band.

16. A compressed air conditioning apparatus according to claim 15, wherein the tolerance values can be input individually and freely selectable, using existing inputting means of the compressed air conditioning apparatus and/or via at least one electric interface of the compressed air conditioning apparatus.

17. A compressed air conditioning apparatus according to claim 1, wherein the internal electronic control unit is designed for initiating a switch-over action of the switch-on valve as a function of the comparison result of the comparator means.

18. A load control device comprising at least one compressed air conditioning apparatus according to claim 1 and an external electronic control device connected or connectable thereto.