CN216153016U

CN216153016U - Pneumatic system

Info

Publication number: CN216153016U
Application number: CN202120256566.6U
Authority: CN
Inventors: J·施米特; E·多马申科; W·文德利希
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2020-02-04
Filing date: 2021-01-29
Publication date: 2022-04-01
Anticipated expiration: 2031-01-29
Also published as: DE102020201300A1; DE102020201300B4

Abstract

The utility model relates to a pneumatic system for supplying compressed air to a compressed air consumer, having a compressed air consumer and having a valve assembly which is designed to influence a fluid flow from a compressed air source to the compressed air consumer, and having a sensor assembly which is assigned to the valve assembly and is designed to detect a change in a functional state of the valve assembly and to provide a sensor signal which is dependent on the functional state, and which is connected to a control assembly which is designed to evaluate the sensor signal and to provide a control signal to the valve assembly. According to the utility model, it is provided that the sensor arrangement comprises an acceleration sensor which is coupled to the valve arrangement and the control arrangement is designed to detect a valve end position as a function of a sensor signal which changes as a function of the functional state.

Description

Pneumatic system

Technical Field

The utility model relates to a pneumatic system for supplying compressed air to a compressed air consumer, having a compressed air consumer and having a valve assembly which is designed to influence a fluid flow from a compressed air source to the compressed air consumer, and having a sensor assembly which is assigned to the valve assembly and is designed to detect a change in the functional state of the valve assembly and to provide a sensor signal which is dependent on the change in the functional state, and which is connected to a control assembly which is designed to evaluate the sensor signal and to provide a control signal to the valve assembly.

Background

From WO 2019/002113 a1 an apparatus for forming plastic parisons into plastic containers with a plurality of injection moulding stations (Blassationen) is known, wherein the injection stations each have a blow molding mechanism which forms a cavity within which a plastic parison can be molded into a plastic container, wherein at least one loading mechanism is provided, by means of which the plastic parison can be loaded with a flowable medium for its expansion and wherein at least one valve mechanism is provided, the valve mechanism is arranged between the at least one pressure reservoir and the loading mechanism and via which the supply and/or discharge of the flowable medium to the loading mechanism can be influenced, at least one adjusting mechanism is provided, by means of which the state of the valve mechanism can be adjusted at a predetermined processing time of the plastic containers.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is to provide a pneumatic system, by means of which an improved compressed air supply to a compressed air consumer can be achieved.

For a pneumatic system of the type mentioned at the outset, this object is achieved by the following features: a pneumatic system for providing compressed air to a compressed air consumer, having a compressed air consumer and having a valve assembly, the valve assembly is configured for influencing a fluid flow from a compressed air source to the compressed air consumer, and a sensor assembly associated with the valve assembly, which sensor assembly is designed to detect a change in the functional state of the valve assembly and to provide a sensor signal dependent on the change in the functional state and is connected to a control assembly, the control assembly is configured for evaluating the sensor signal and for providing a control signal to the valve assembly, characterized in that the sensor assembly comprises an acceleration sensor coupled with the valve assembly and the control assembly is configured for detecting a valve end position from a sensor signal that is dependent on the change in the functional state. In this case, it is provided that the sensor arrangement comprises an acceleration sensor which is coupled to the valve arrangement and the control arrangement is designed to detect the valve end position as a function of a sensor signal which changes as a function of the functional state. In the case of the use of an acceleration sensor for detecting the end position of the valve, it is advantageous if no special measures have to be provided at the valve mechanism to enable scanning through the sensor arrangement. For example, when detecting the valve end position by means of a magnetic-field-sensitive sensor, it must be provided that the valve ring of the valve assembly, which is mounted movably in the valve housing, is provided with a permanent magnet, which can then be scanned by means of the magnetic-field-sensitive sensor assembly. In contrast, when the valve end position is detected by means of an inductive proximity sensor (N ä herengsschalters), it is necessary for the sensor arrangement necessary for this to be arranged in direct proximity to the respective valve end position for the valve member movably mounted in the valve housing, in order to be able to detect a change in the magnetic field provided by the proximity sensor, which change depends on the position of the valve member. In contrast, when an acceleration sensor is used to determine the valve end position, a particularly physical proximity between the sensor assembly and the valve assembly is not necessary. Rather, it is sufficient for the sensor assembly to be fastened, for example, to a carrier plate, to which the valve assembly is also fastened. In an exemplary embodiment, the valve member can be moved into a valve housing of the valve assembly by a valve member, which is movably accommodated in the valve housing of the valve assembly in order to influence the flow of compressed air for the compressed air consumer. The acceleration of the valve housing occurring here can be transmitted further via the carrier plate to the sensor assembly.

The control assembly can relate to a local valve controller with a microprocessor, which is designed to actuate the valve assembly and which can communicate with a machine controller of a higher level, if appropriate, in order to synchronize with other machine components, for example a blow-molding machine. Alternatively, it can be provided that the control assembly comprises a plurality of control components arranged in a distributed manner, wherein one is designed as a valve controller and the other as a machine controller, in particular as a controller which can store a program, and thereby enables complete control of the blow molding machine, for example.

Advantageous refinements of the utility model are explained below.

The valve assembly expediently comprises at least one switching valve having a valve housing with an inlet connection and an outlet connection and a valve ring, in which the valve member is movably accommodated in the valve housing in order to release a fluid channel extending between the inlet connection and the outlet connection in the open position and to close said fluid channel in the closed position, and the control assembly is designed to detect the arrival of the open position and/or the closed position for the valve member. The switching valve has the task of influencing the compressed air volume flow in such a way that a favorable use of the compressed air consumer is ensured. For this purpose, it can be provided that the pneumatic system is connected to a compressed air source which is in fluid-communicating connection with the inlet connection of the valve housing and which is designed to provide compressed air to the valve assembly. The switching valve can be an 2/2 bypass valve, in particular a central valve (Sitzventil) or a slide valve. Depending on the position of the valve member movably accommodated in the valve housing between the closed position and the open position, the compressed air provided by the compressed air source can flow through a fluid channel formed in the valve housing and be made available to the compressed air consumer at the outlet connection of the valve assembly or be blocked in terms of the flow through of the fluid channel by the valve member, so that no supply of compressed air to the compressed air consumer takes place. The control assembly has the task of determining a change in the functional state of the valve assembly, in particular the reaching of the open position and/or the reaching of the closed position, as a function of the sensor signal of the sensor assembly. The control assembly can thus determine, for example, the switching time, i.e. the duration between the provision of control signals for the movement of the valve element between the open position and the closed position and/or between the closed position and the open position of the valve assembly. In addition or alternatively, the control module can determine the time at which the respective functional state, i.e. the open position or the closed position, is assumed, in order to be able to derive information therefrom regarding the continued operation of the pneumatic system, such as, for example, the next switching time for the valve assembly.

It is preferably provided that the switching valve is assigned an electrically actuable pilot valve which is electrically connected to the control module and has a pneumatic control outlet which is pneumatically connected to the pneumatic control inlet of the switching valve and to which the switching valve which is pneumatically pre-controlled by the pilot valve is connected to the compressed air consumer and is designed for arrangement between the compressed air source and the compressed air consumer. The pilot valve can be, for example, a solenoid valve which can be switched between a closed state and an open state depending on a control signal of the control assembly and in the open state provides a connection for fluid communication between the compressed air source and the switching valve. The pneumatically controlled switching valve requires only a small compressed air volume in order to perform the desired switching between the two functional states, i.e. the open position and the closed position, so that the entire switching process starting from the supply of the control signal of the control module to the pilot valve until the desired functional state is assumed can be performed in a time interval of a few milliseconds. Typical values for the switching time of the pilot valve can be assumed to be 2 milliseconds. Typical values for the switching time of the switching valve can be assumed to be at 5 milliseconds. The control unit can be set up, for example, in such a way that it determines the time interval between the supply of the control signal to the pilot valve and the detection of the acceleration value from the sensor signal supplied by the sensor unit, from which the impact of the valve collar of the switching valve at the valve housing can be derived when the corresponding functional state is assumed. Depending on the time interval, it is possible on the one hand in the control module to determine the time at which or from which a subsequent switching process for the valve arrangement is triggered by the control module. In addition or alternatively, the wear state of the valve assembly can be determined from the time intervals, in particular by comparison with the time intervals determined and stored before in time, since it is possible to proceed from the fact that the switching time increases with increasing valve wear due to increased friction for the valve ring segments of the switching valve and, if appropriate, also due to increased friction for the valve ring segments of the pilot valve. Preferably, the sensor arrangement can be coupled to the valve arrangement in such a way that it is possible to determine the occupation of the functional state of the switching valve as well as the occupation of the functional state of the pilot control valve. Thereby a more accurate analysis of the behavior of the pneumatic system is achieved.

In a development of the utility model, it is provided that the valve assembly comprises a plurality of switching valves and that the acceleration sensor is designed to detect a respective functional state of the plurality of switching valves. In an exemplary embodiment, a plurality of switching valves can be used to supply the compressed air consumer with compressed air in a predetermined temporal sequence in order to reach a respective pressure level that can be set higher and to obtain a pressure drop for the compressed air consumer to the pressure level that can be set higher by drawing compressed air out of the compressed air consumer in the predetermined temporal sequence. In this application of a plurality of switching valves or also in other applications of a plurality of switching valves, the advantage of the use of a sensor arrangement designed as an acceleration sensor initially yields a gain, since a plurality of, preferably all, switching valves of the valve arrangement can be evaluated with regard to their respective occupation of the functional state by means of a single acceleration sensor. In this case, it is assumed that the control unit carries out the actuation of the respective switching valve over time, wherein a temporal overlap of the first switching process for the first switching valve and the second switching process for the second switching valve is excluded, in order to avoid a misinterpretation of the occurring acceleration by the control unit, which is measured by means of the acceleration sensor. In particular, it is preferably provided that a temporally subsequent actuation of the switching valve is initially assumed that the function state that can be preset is successfully assumed by the temporally previously actuated switching valve.

In a further embodiment of the utility model, it is provided that the sensor arrangement comprises a pressure sensor which is arranged at the inlet connection of the switching valve or at the outlet connection or at the pneumatic control inlet or at the pneumatic control outlet of the pilot control valve and is designed to detect a fluid pressure, in particular a supply pressure or a control pressure, and to provide a sensor signal dependent on the fluid pressure to the control arrangement and/or the control arrangement is designed to adapt a control signal for the pilot control valve dependent on the sensor signal of the sensor arrangement. By means of the pressure sensor, it can be determined, for example, whether the supply pressure, at which a sufficient compressed air supply to the compressed air consumer is ensured or whether a possible deviation of the supply pressure from the presettable range requires a shortening or lengthening of the control time for the valve assembly, is within a presettable range. Alternatively, it can be determined by means of a pressure sensor whether the control pressure for actuating the switching valve is sufficient to be able to carry out the switching process of the switching valve within a presettable duration. Depending on the at least one sensor signal, it can be necessary for the control module to adapt the control signal for the pilot control depending on the at least one sensor signal. The sensor signal can relate either only to a sensor signal of an acceleration sensor or, in particular, only to a sensor signal of a pressure sensor. It is alternatively provided that the control unit is designed to take into account not only the sensor signal of the acceleration sensor but also the sensor signal of at least one pressure sensor, in particular the sensor signals of both pressure sensors, when adapting the control signals for the pilot control valve. In this case, the adaptation of the control signal can comprise not only a change of the point in time for providing the control signal but also a change of the duration for providing the control signal.

Advantageously, the valve assembly is assigned a compressed air consumer in the form of a blow mold and the blow mold is designed for producing a plastic hollow body. Such blow moulds are used in stretch blow moulding processes, as they are used in the production of plastic hollow bodies, in particular in the production of beverage bottles made of PET (polyethylene terephthalate). In order to prepare such a stretch blow molding process, the blank, also referred to as a plastic parison, is heated to a temperature which effects plastic deformation of the plastic material. The blank is received in a mold cavity of a blow mold, which is typically formed by two mold halves mounted so as to be movable relative to one another, and is placed on a compressed air connection belonging to the blow mold. The two mold halves are then moved relative to one another in such a way that the mold cavity forms a closed volume and a compressed air supply takes place from a compressed air source through the valve assembly to the blow mold at the compressed air connection. In this case, the preformed cavity in the blank is enlarged, so that the plastic material comes into contact with the wall section of the mold cavity by plastic deformation and thereby describes the geometry of the mold cavity. Then, after sufficient cooling of the now almost produced plastic hollow body, the opening of the blow mold and the removal of the plastic hollow body can be carried out by a relative movement of the two mold halves. The supply of compressed air to the blow mold usually takes place in a plurality of steps, wherein at the end of each step a preset pressure level is set. In the same way, the extraction of compressed air from the blow mold also usually takes place in a plurality of steps. Accordingly, a plurality of ventilation valves and a plurality of venting valves are associated with each blow mold, the change in the functional state of which can preferably be detected by a single acceleration sensor.

Expediently, a plurality of blow moulds are arranged in a circular manner on a blow wheel which is rotatably mounted on the machine frame and in which the valve assemblies assigned to the blow moulds are arranged in the (berandeten) inner circle of the blow wheel which is bordered by the blow moulds. The circular arrangement of the blow moulds in this case allows the integration of the pneumatic system into a continuous or clocked production line (Taktverfahren), in which preheated blanks, for example made of plastic, are supplied to the blow moulds arranged on the blow wheel in a suitable working cycle at a loading position and the plastic hollow bodies can be removed from the blow moulds after the blow moulding process is carried out in an unloading position in order to carry out further processing thereof. Since the blow moulds have to be accommodated on the blow wheel in such a way that the mould halves can perform a relative movement with respect to one another, and since the blow moulds are arranged for integration into the production line in a region of the preferably disk-shaped blow wheel which is radially on the outside, a substantially circular inner face results in the region of the blow wheel which is radially on the inside, which inner face can be used for space-saving arrangement of the valve assembly. Accordingly, the valve assembly performs a rotational movement equivalent to that of the blow mold, so that a complex rotational movement for the fluid lines extending between the valve assembly and the respectively associated blow mold is not necessary.

In a further embodiment of the utility model, it is provided that the valve arrangement is arranged in a star-shaped manner with respect to the axis of rotation of the blow-moulding wheel and that a sensor arrangement for detecting the functional state of the valve arrangement is arranged centrally in the region of the axis of rotation of the blow-moulding wheel and/or that the valve arrangement and the sensor arrangement are arranged on a carrier plate, and that the carrier plate is connected to the blow-moulding wheel by means of a vibration damper. It is provided, for example, that the blow mold and the associated valve assembly are arranged on a common axis which extends radially outward from the axis of rotation of the blow wheel. In the case of such an assignment of the valve assemblies to the blow mold, a star-shaped arrangement of the valve assemblies results in the case of a plurality of blow molds accommodated on the blow wheel and the assigned valve assemblies. This enables a space-saving design for the blowing wheel and the components accommodated therein. By arranging the sensor arrangement in the central region of the blow-moulding wheel, for example in the region of the axis of rotation of the blow-moulding wheel, it is ensured that the spacing of the sensor arrangement relative to the valve arrangement accommodated on the blow-moulding wheel is as equal as possible, in order to achieve the same type of scanning of all valve arrangements by the sensor arrangement. In addition or alternatively, it can be provided that the carrier plate accommodated by means of the vibration damper at the blow wheel is designed to accommodate the valve assembly and the sensor assembly in order to ensure a largely vibration-related decoupling of the sensor assembly from the blow wheel and a drive coupled thereto, which is arranged at the machine frame and is designed to introduce a rotational movement onto the blow wheel.

In an advantageous development of the utility model, it is provided that the control module has an electrical interface, in particular a bus interface, wherein the interface is designed for receiving control commands for the valve module. In principle, it can be provided that the control assembly is designed for autonomous actuation of the at least one valve assembly. When integrating the pneumatic system into a production line, which is configured for example for the batch production of PET bottles, it is advantageous if the control assembly can be operated synchronously with the upstream and/or downstream production units. For this purpose, the control module has an electrical interface, at which a higher-level machine controller, in particular a control command of a coded controller (SPS), can be provided, which can be used to influence the control behavior of the control module. The control commands can in particular relate to commands directed to the control assembly, which are converted in the control assembly into corresponding control signals for actuating the pilot control valve. Alternatively, the control commands can relate to commands for upstream and/or downstream production units, from which the control module can derive information for actuating the valve assembly, such as, for example, a clock signal. Such transfer of control commands between the machine controller and the control components at the upper level can be performed in a similar manner. The transmission of the control commands between the machine controller and the control module of the higher level is preferably carried out in digital form, in particular in the form of bus telegrams, wherein the interface is in this case designed as a bus interface.

Preferably, it is provided that the control unit comprises artificial intelligence for pattern recognition (musterkennung) from at least one sensor signal of the sensor unit. The artificial intelligence relates to computer programs, for example, that can learn, and more particularly to neural networks. The task of artificial intelligence is to recognize from a plurality of signal levels of the acceleration sensor that occur with strongly varying frequencies and strongly varying amplitudes, a signal level that is actually caused by a change, in particular an occupation, of the switching valve of the valve assembly or, if appropriate, a change in the functional state of the pilot valve. In an exemplary manner, it can be provided that the artificial intelligence is supplied with additional information about the specific occupation of the respective functional state of the respective actuated valve assembly during the evaluation of the signal profile of the acceleration sensor during the initialization phase for the pneumatic system, in order to thereby learn, within the scope of a learning process, a reliable distinction between a collision of the valve collar of the switching valve or pilot valve at the respective valve housing and other accelerations (as typically occurs during operation of the pneumatic system). It can be provided, for example, that the artificial intelligence is set up such that it does not evaluate the sensor signal of the sensor arrangement for a period of time in which, for technical reasons, it is not possible to take up the functional status of the valve arrangement monitored by the sensor arrangement. This can be achieved in particular by including the control signal of the control assembly which is supplied to the pilot control valve. It can also be provided that the artificial intelligence is designed to factor in the control commands of the machine controller of the upstream stage, wherein the control commands can be sent to a production device arranged upstream or downstream and that the artificial intelligence, during an initialization phase, has learned which acceleration can be transmitted via the production device to the blow-moulding wheel, without the acceleration indicating a change in the functional state of the valve assembly to be monitored.

Advantageously, the control module is designed, in particular using artificial intelligence, to be able to provide status information about the operating principle of the valve module. Such status information can, for example, consist in that a deviation between a stored switching time for the valve assembly and a actually determined switching time for the valve assembly already exceeds a threshold value, from which it can be derived, for example, that the maximum service life of the valve assembly is reached or will soon be reached. Such status information can be issued by the control component, particularly in the illustration according to VDMA 24526.

Drawings

The utility model is explained in more detail subsequently on the basis of the figures. Wherein the content of the first and second substances,

figure 1 shows a strictly schematic top view of a blow-moulding wheel towards a stretch blow-moulding machine not shown in more detail,

FIG. 2 shows a highly schematic, partially cut-away front view of the blow-moulding wheel according to FIG. 1, an

Fig. 3 shows a very schematic representation of a pneumatic circuit, as it can be used for compressed air supply of blow molds arranged on the blow wheel according to fig. 1 and 2.

Detailed Description

The pneumatic system 1 shown in fig. 1 and 2 purely exemplarily comprises a blow wheel 2 configured for application in a stretch blow molding machine which is not shown in more detail. The blowing wheel 2 is accommodated in a rotationally movable manner about a rotational axis 3 at a machine frame 4 and is configured purely exemplarily in a disk shape. In the purely exemplary machine frame 4, which is designed in a box-like manner, a drive mechanism, not shown in greater detail, is accommodated for introducing a rotational movement about the axis of rotation 3 onto the blow wheel 2 and a compressed air source, also not shown, which can be designed, for example, as a high-pressure compressor.

On the upper side 5 of the blowing wheel 2, a plurality of blowing molds 6 are arranged on a circle 7, wherein the circle 7 is oriented coaxially to the axis of rotation 3. For reasons of clarity, only a small number of blow moulds 6 are arranged on the blow-moulding wheel 2, in practice 30 to 40 or more blow moulds can also be arranged on the blow-moulding wheel. The blow mold 6, which is embodied purely exemplarily in a cylindrical manner, has a first mold half 8 and a second mold half 9, respectively, which are linearly movable relative to one another in the illustrated plane of fig. 1, in order to be able to transfer the blow mold from an open state 10 into a closed state 11 and back into the open state 10, respectively. It is provided by way of example that the blow-moulding wheel 2 performs a continuous rotational movement about the rotational axis 3 in the clockwise direction, so that each of the blow-moulding tools 6 passes through the loading position 15 and each of the blow-moulding tools 6 passes through the unloading position 16. It is provided by way of example that, during the course of the rotational movement of the blow-moulding wheel 2, when the respective blow-moulding tool 6 approaches the unloading position 16, an opening process for the blow-moulding tool 6 takes place by means of a drive, not shown, which is integrated in the blow-moulding wheel, in which the two

tool halves

8, 9 are moved linearly away from one another in opposite directions. Accordingly, at the unloading position 16, the plastic hollow bodies 18 molded in the respective blow molds 6 can be removed from the blow molds 6 and supplied to a subsequent process step, which can be carried out by means of a downstream production device, which is not shown in greater detail. Proceeding from the unloading position 16, the respective blow mold 6 remains in the open state until the loading position 15 is reached, at which a supply of blanks 17, also referred to as plastic parisons, which are supplied preheated into the respective blow mold 6 and can be placed into a compressed air connection formed in the blow mold 6, takes place. The blow mold is then closed by the linear approach of the two

mold halves

8, 9 and, during the rotational movement of the blow wheel 2 about the rotational axis 3, the desired blow molding process can be carried out by the compressed air supply into the blow mold 6, which must not be ended until the unloading position 16 is reached.

As can also be seen from the illustration in fig. 1, each of the blow moulds 6 is assigned a valve assembly 25 which is designed for ventilating and venting the respective blow mould and which, as described in greater detail below, comprises a plurality of switching valves and pilot valves. It is provided by way of example that the valve assembly 25 is arranged in a star-shaped manner with respect to the axis of rotation 3, as a result of which a space-saving arrangement of the valve assembly 25 at the blow-moulding wheel 2 can be achieved. Furthermore, purely by way of example, it is provided that a control assembly 26 is arranged in the interior region of the blowing wheel 2 limited by the valve assemblies 25, said control assembly being electrically connected to the respective valve assembly 25 via a control line 27. Purely exemplarily, a first sensor arrangement configured as an acceleration sensor 28 is disposed at each of the valve assemblies 25, which first sensor arrangement is electrically connected to the control assembly 26 and which first sensor arrangement is configured for determining an acceleration caused by a switching process of the respective valve assembly 25.

The control unit 25 is provided, for example, with an interface which enables the control unit 25 to be connected to a data line, not shown, in particular a bus line of a bus communication system. The control module 25 can thus be connected to the data line either as a purely passive, listening (mith minitor) participant and process control commands communicated on the data line for its own purpose. Alternatively, the control module 25 is designed for bidirectional communication with further components of the production line, which are also not shown, connected to the data lines and for this purpose can, for example, receive and transmit digital bus telegrams.

In order to obtain a mechanical decoupling of the valve assembly 25 and the acceleration sensor 28 from the vibrations of the machine frame 4 and the blowing wheel 6 and the accelerations associated therewith to the greatest possible extent, it is provided that the valve assembly 25 and the control assembly 26 are arranged on a common carrier plate 29. The carrier plate 29, which is embodied purely exemplarily in the form of a circular ring, is fastened to the blow-moulding wheel 2 by means of a vibration damper 30, which can be purely exemplarily a rubber-metal structural component, wherein the vibration damper 30 ensures a presettable damping of vibrations transmitted from the machine frame 4 and from the blow-moulding wheel 6 to the carrier plate 29.

As can be derived from the illustration of fig. 2, each of the valve assemblies 25 purely exemplarily comprises four valve modules 31 stacked on one another in the vertical direction, wherein each of the valve modules 31 comprises a pilot valve 250 shown in more detail in fig. 3 and a switching valve 51. It is provided by way of example that two of the valve modules 31 of the respective valve assemblies 25 are used as ventilation valves and the other two valve modules 31 of the respective valve assemblies 25 are used as ventilation valves. In practice, usually up to five valve modules are used as ventilation valves and up to five valve modules are used as ventilation valves. In practice, it is also provided that the ventilation and ventilation valves of the plurality of blow moulds are connected to one another in a pneumatic manner such that, for example, when a ventilation process for the blow moulds is carried out, the use of compressed air for the already ventilated blow moulds can take place in order to achieve a prespecifiable pressure level, which should be ventilated from a higher pressure level at the time point in order to thus ensure an advantageous multiple use of the supplied compressed air.

In order to ensure an advantageous mode of operation for the pneumatic system 1, it is provided that the occupation of the functional state is determined for the respective valve assembly 25. For this purpose, a respective acceleration sensor 28 is used, which is electrically connected to the control assembly 26 and is designed to detect an acceleration caused by the switching process of the valves of the respective valve assembly 25.

In fig. 3, for reasons of clarity, only two valve modules 31 are shown, wherein a ventilation module 32 and a ventilation module 33 are referred to here. Purely exemplarily, the ventilation module 32 comprises a first pilot valve 52 and a first switching valve 54. Further, the exhaust module 33 includes a second pre-control valve 53 and a second switching valve 55. It is provided by way of example that the two

pilot valves

52 and 53 are identically constructed. Furthermore, it is provided that the two switching

valves

54 and 55 are configured identically.

For the sake of simplicity, only the supply of the blow moulds 6 directly from the compressed air source 41 is furthermore shown, in practice the valve modules 31 of the blow moulds 6 are pneumatically connected with the valve modules 31 of the preceding and subsequent blow moulds 6, in order to be able to achieve multiple utilization of the compressed air in the different pressure stages of the individual blow moulds 6.

As can be taken from fig. 3, the first pilot valve 52 and the first switching valve 54 as well as the second switching valve 55 are connected in fluid communication with the compressed air source 41. In this case, a first pilot control valve 52, which is electrically connected to the control assembly 26 via a control line 27, serves to influence the fluid flow between a first control outlet and a first control inlet 56 of a first switching valve 54. It can be provided by way of example that the first switching valve 54 can be transferred from the closed position according to fig. 3 into an open position, not shown, when the connection of the fluid communication between the compressed air source 41 and the first control inlet 56 is released by means of the first pilot control valve 52 connected therebetween in dependence on a control signal of the control assembly 26. In this case, the connection of the fluid communication between the compressed air source 41 and the compressed air connection 40 associated with the blow mold 6 is released by the first switching valve 54, so that compressed air can flow from the compressed air source 41 into the blow mold 6, whereby a plastic hollow body can be produced with the blow mold closed and a blank not shown placed onto the compressed air connection 40. Accordingly, the first pilot valve 52 and the first switching valve 54 form the vent valve 32.

To end the blow molding process, the control signal for the first pilot valve 52 is first switched off, whereby the first pilot valve 52 is transferred into the closed position according to fig. 3. As a result, the control pressure provided at the first control inlet 56 of the first switching valve 54 is reduced in pressure, as a result of which the first switching valve 54 is guided from an open position, not shown, into a closed position according to fig. 3.

The control module 26 can then initiate a switching of the second pilot valve 53 and thus a supply of compressed air from the second control outlet to the second control inlet 57 of the second switching valve 55 by supplying a control signal via the associated control line 27 to the second pilot valve 53, as a result of which it is brought from the closed position according to fig. 3 into an open position, which is not illustrated. In the open position, a flow of compressed air out of the blow mold 6 into an outflow line 60 is achieved, which can be connected, for example, to a valve module 31 of a downstream blow mold 6 in order to achieve a compressed air supply there, without the compressed air supplied by the compressed air source 41 having to be used.

For a reliable execution of the blow molding process and for ensuring a complete shaping of the inner surface of the blow mold 6 by means of the blank 17, it is provided that the control assembly 26 is electrically connected to the acceleration sensor 28 and comprises a processor 45 which is configured for evaluating the sensor signal of the acceleration sensor 28 and for electrically operating the

pilot valves

52 and 53 by means of suitable control signals. For this purpose, the processor 45 has an electrical output stage, not shown in greater detail, which is able, for example, to convert the digital control signals of the processor 45 into corresponding control currents for the

pilot valves

52 and 53.

It can be provided, for example, that the processor 45, which is designed to execute a fixedly or interchangeably stored computer program, does not evaluate the sensor signal of the respective acceleration sensor 28 before the control signal is supplied to one of the two

pilot valves

52 or 53. Preferably, the processor 45 is provided to evaluate the sensor signal of the respective acceleration sensor 28 after issuing a control signal to one of the two

pilot valves

52 or 53. It can be provided, for example, that the respective acceleration sensor 28 is arranged in relation to the

pilot valves

52 and 53 and in relation to the switching

valves

54 and 55 in such a way that it can detect all accelerations which occur when a valve collar of the valves 52 to 57, which is not shown in greater detail, hits into the respective functional position, that is to say into the open position or the closed position.

By evaluating the sensor signal of the respective acceleration sensor 28, the processor 45 can, for example, determine the time interval that elapses between the emission of a control signal to one of the two

pilot valves

52 or 53 and the acceleration that results from the collision of the respective valve loop, not shown, into the respective functional position, and thus obtain knowledge about the switching time of the

respective pilot valve

52 or 53. Furthermore, the processor 45 can carry out an evaluation of the sensor signal of the respective acceleration sensor 28 in a time window in which a switching process for the

respective switching valve

54 or 55 can be expected, in order to be able to deduce therefrom what extent the switching time of the

respective switching valve

54 or 55 lies within a presettable time range. It is particularly advantageous if the processor 45 is set up in such a way that it can bring both the acceleration occurring as a result of the switching process of the

respective pilot valve

52 or 53 and the acceleration occurring as a result of the switching process of the

respective switching valve

54 and 55 into a temporal relationship with the supply of the control signal to the

respective pilot valve

52 or 53. The processor 45 can thus draw conclusions about not only the switching time for the

respective pilot valve

52 or 53 but also about the switching time for the

respective switching valve

54 or 55.

Furthermore, the processor 45 can execute the actuation of further not shown ventilation and ventilation modules assigned to the respective blow mold 6 as a function of the time at which the attainment of the predetermined functional position by the respective valve 52 to 55 as a function of the acceleration determined by the respective acceleration sensor 28 can be determined.

In addition, it can be provided that the processor 45 takes into account the change in the switching times of the valves 52 to 55 in such a way that, in the case of a plurality of valve assemblies 25 to be actuated, it selects the time points for actuating the

respective pilot valves

52, 53 in such a way that, on the one hand, no large pressure fluctuations are ensured with respect to the supply pressure provided by the compressed air source 41 and, on the other hand, it is advantageously ensured that the compressed air which has been supplied to the blow mold 6 is used for pressure loading of the further blow mold 6.

It can optionally be provided that the ventilation module 32 is assigned a first pressure sensor 46 which is electrically connected to the processor 45 of the control module 26 and which is pneumatically connected to a first inlet connection 58 at a valve housing 61 of the first switching valve 54, whose first outlet connection 62 is connected to the compressed air connection 40. The supply pressure provided by the compressed air source 41 can be determined by means of the first pressure sensor 46, so that the control unit 26 can adapt the opening duration for the vent valve 32, if necessary. For this purpose, the processor 45, using a computer program stored therein, determines an opening time for the ventilation module 32, which is dependent on the supply pressure of the compressed air source 41, and actuates the first pilot control valve 52 accordingly.

Such a pressure sensor 46 can also be provided for a ventilation module, not shown, which is not coupled to the compressed air source 41 but to a ventilation module, not shown, of the upstream blow mold, since pressure fluctuations can likewise occur here, which may require a change in the opening duration for the respective ventilation module, not shown.

In addition or as an alternative to the first pressure sensor 46, a second pressure sensor 47 can be provided, which is designed to determine the control pressure provided by the first pilot valve 52 to the switching valve 54 and which is electrically connected to the processor 45 of the control unit 26. Based on the sensor signal provided by the second pressure sensor 47, which is dependent on the measured control pressure, the control assembly 26 can determine whether there is sufficient control pressure to switch the switching valve 54.

The acceleration sensor 28, the first pressure sensor 46 and/or the second pressure sensor 47 form a sensor arrangement 20 for the pneumatic system shown purely exemplary in fig. 1 to 3.

It is preferably provided that the computer program running on the processor 45 is equipped with learning capabilities, which are also referred to as artificial intelligence and which can be implemented in particular in the form of a neural network. The processor 45 is thus positioned in a position such that, even in the event of difficult boundary conditions, such as disappearing sensor signals and/or vibration influences which are transmitted from the machine frame 4 to the blow wheel 2 and via the vibration damper 30 to the carrier plate 29, a reliable recognition of accelerations which result from the impact of the respective valve ring segment in the respective functional position is carried out.

Claims

1. Pneumatic system (1) for supplying compressed air to a compressed air consumer (6), having a compressed air consumer (6) and having a valve assembly (25) which is designed for influencing a fluid flow from a compressed air source (41) to the compressed air consumer (6), and having a sensor assembly (20) which is assigned to the valve assembly (25) and which is designed for detecting a change in the functional state of the valve assembly (25) and for providing a sensor signal which is dependent on the change in the functional state and which is connected to a control assembly (26) which is designed for evaluating the sensor signal and for providing a control signal to the valve assembly (25), characterized in that the sensor assembly (20) comprises an acceleration sensor (28), the acceleration sensor is coupled to the valve assembly (25) and the control assembly (26) is designed to detect a valve end position as a function of a sensor signal that changes as a function of the functional state.

2. Pneumatic system (1) according to claim 1, characterized in that the valve assembly (25) comprises at least one switching valve (54, 55) having a valve housing (61) with an inlet coupling (58) and an outlet coupling (62) and a valve ring movably accommodated in the valve housing (61) in order to release a fluid channel extending between the inlet coupling (58) and the outlet coupling (62) in an open position and to close the fluid channel in a closed position, and in that the control assembly (26) is configured for detecting the reaching of an open position and/or a closed position for the valve ring.

3. Pneumatic system (1) according to claim 2, characterised in that the switching valves (54, 55) are assigned an electrically controllable pilot valve (52, 53) which is electrically connected to the control assembly (26) and has a pneumatic control outlet which is pneumatically connected to a pneumatic control inlet (56, 57) of the switching valve (54, 55) and to which the switching valve (54, 55) which is pneumatically pre-controlled by the pilot valve (52, 53) is connected to the compressed air consumer (6) and is designed for arrangement between the compressed air source (41) and the compressed air consumer (6).

4. A pneumatic system (1) according to claim 2 or 3, wherein the valve assembly (25) comprises a plurality of switching valves (54, 55) and the acceleration sensor (28) is configured for detecting respective functional states of the plurality of switching valves (54, 55).

5. The pneumatic system (1) according to claim 3, characterized in that the sensor assembly (20) comprises a pressure sensor (46, 47) arranged at an inlet connection (58) or at an outlet connection (62) of the switching valve (54, 55) or at a pneumatic control inlet or at a pneumatic control outlet of the pilot valve (52, 53), which pressure sensor is configured for detecting a fluid pressure and for providing a sensor signal dependent on the fluid pressure to the control assembly (26) and/or the control assembly (26) is configured for matching a control signal for the pilot valve (52, 53) dependent on the sensor signal of the sensor assembly (20).

6. Pneumatic system (1) according to claim 1 or 2, characterised in that a compressed air consumer (6) configured as a blow mould is assigned to the valve assembly (25) and the blow mould is configured for producing a plastic hollow body.

7. Pneumatic system (1) according to claim 6, characterised in that a plurality of blow moulds are arranged circularly at a blow wheel (2) which is rotatably supported at a machine frame (4) and in that valve assemblies (25) respectively assigned to the blow moulds are arranged in the inner circle of the blow wheel (2) which is bordered by the blow moulds.

8. The pneumatic system (1) according to claim 7, characterized in that the valve assembly (25) is arranged star-shaped with respect to the rotational axis (3) of the blow-moulding wheel (2) and a sensor assembly (20) configured for detecting a functional state of the valve assembly (25) is arranged centrally in the region of the rotational axis (3) of the blow-moulding wheel (2) and/or the valve assembly (25) and the sensor assembly (20) are arranged on a carrier plate (29), and the carrier plate (29) is connected with the blow-moulding wheel (2) by means of a vibration damper (30).

9. The pneumatic system (1) according to claim 1 or 2, wherein the control assembly (26) has an electrical interface, wherein the interface is configured for receiving control commands for the valve assembly (25).

10. The pneumatic system (1) according to claim 1 or 2, characterized in that the control assembly (26) comprises artificial intelligence for pattern recognition from at least one sensor signal of the sensor assembly (20).

11. Pneumatic system (1) according to claim 5, characterized in that the pressure sensor is configured for detecting a supply pressure or a control pressure.

12. The pneumatic system (1) according to claim 9, characterized in that the control assembly (26) has a bus interface.