Valve assembly

Abstract

Valve assembly with a valve housing (20) through which a fluid channel (21) is penetrated, in which a valve seat (24) and a valve element (22) which is movably mounted relative to the valve seat (24) are formed, with an electromechanical actuating means (23) for moving the valve element (22) between at least two functional positions to influence a free cross-section of the fluid channel (21) and with a control device (44; 54) which is configured to actuate the actuating means (23) depending on a control signal and which includes a delay means (45; 55) which, in the event of a valve shut-off process, is configured for a time-delayed movement of the valve element (22) into a shut-off position, wherein the control device (44; 54) and the delay means (45;55) are designed as electrical circuits and comprise an electrical energy storage device (47, 57) which is designed for energy-autonomous movement of the valve element (22) into the shut-off position during the valve shut-off process and wherein the control device (44; 54) is designed to provide a start signal to the delay means (45; 55) in the absence of a control signal and / or in the event of a supply voltage being switched off in order to initiate the valve shut-off process.;

Description

[0001] The invention relates to a valve device with a valve housing which is penetrated by a fluid channel in which a valve seat and a valve element which is movably mounted relative to the valve seat are formed, with an electromechanical actuating means for moving the valve element between at least two functional positions in order to influence a free cross-section of the fluid channel and with a control device which is designed to actuate the actuating means depending on a control signal and which includes a delay means which, in the event of a valve shutdown process, is designed for a time-delayed movement of the valve element into a shutdown position.

[0002] According to an undocumented prior art, a valve device is known for use in process plants such as chemical or bioreactors, or in machine tools such as lathes or milling centers. The known valve device is used to supply a fluid flow, in particular a compressed air flow, to a fluid consumer connected to the valve device, especially an actuator. The fluid supply is intended to be maintained for a certain period of time even after the shutdown of a central control system, such as a programmable logic controller (PLC), which is designed to control the valve device and the entire process plant or machine tool.By pressurizing the fluid consumer beyond its actual operating time, a flushing process can be ensured for the fluid consumer, for example, after the process plant or machine has been shut down. This flushing process serves, for instance, to prevent the unwanted ingress of cleaning fluids into fluid-pressurized areas of the fluid consumer. The known valve assembly comprises a pneumatic timer for this purpose, which is activated after the electrical supply voltage provided to the valve assembly during regular operation is switched off and, after a predefined time period, ensures a purely pneumatic movement of the associated valve element into a shut-off position.

[0003] EP 1 809 935 B1 discloses a regenerative thermal oxidation device with at least first and second heat exchange columns, each associated with a combustion zone, a valve for directing a gas flow into and out of the columns, and a drive means for actuating the valve, wherein the drive means for actuating the valve comprises an electric motor, and further comprises: means associated with the motor for increasing the torque output of the motor, and wherein the drive means comprises: a motor brake, a first position sensor for causing the motor to stop when the valve reaches a predetermined position, and a second position sensor for causing the motor to slow down when the valve reaches a second predetermined position

[0004] DE 10 2008 027 544 A1 discloses a safety valve device in which a valve which can be magnetically actuated, for example by a pull solenoid, and which can be held in the open position thermoelectrically is arranged in series with a bipolar valve with respect to the gas flow and the two valves are used alternatively for opening and closing in order to carry out function and condition monitoring with each closing cycle.

[0005] DE 44 10 103 C1 discloses a drive of fluidic or electrical design with a control system for the driving force transmitting element, including damping in at least one end position of the at least single-acting driving force element, optionally in addition to mechanical shock absorbers, wherein sensors are arranged in the region of the end positions. To achieve a particularly smooth approach to the end position of the driving force element, it is proposed that the control system include a counter-pulse module which, via a pre-positioning sensor assigned to at least one direction of movement, effects a time-adjustable switching of a energized first switching element assigned to a first end position to a previously unenergized second switching element assigned to a second end position.

[0006] DE 693 27 787 T2 discloses a failsafe circuit for ensuring the movement of a ventilation flap or valve into a failsafe position in the event of a power supply failure, comprising: a miniature rotary motor connected to the ventilation flap or valve to adjust the ventilation flap or valve within a range of several positions, a control circuit connected to the motor and which can be connected to a power supply line to be energized by it in the normal operating state and which, in the normal operating state, is used to control the motor and thus the position of the ventilation flap or valve, wherein the motor is operated at a given torque in the normal operating state to adjust the ventilation flap or valve, and failsafe devices which ensure thatthat the ventilation flap or valve is moved to its failsafe position in the event of a power failure, the failsafe devices consisting of: a capacitive power supply connected to the power supply line in a charging circuit, the charging circuit providing for the continuous charging of the capacitive power supply and functioning in such a way that the capacitive power supply is isolated in the normal operating state so that the motor is not energized by it; a sensor arrangement connected to the power supply line and consisting of a switch which is actuated in the event of a power failure and establishes the connection to the capacitive power supply to provide the energy to drive the motor so that the ventilation flap or valve is moved to its failsafe position.

[0007] The object of the invention is to provide a valve device with which the valve shut-off process can be carried out more precisely.

[0008] This problem is solved for a valve device of the type mentioned above with the features of claim 1. It is provided that the control device and the delay means are designed as electrical circuits and include an electrical energy storage device which, during a valve shutdown process, is configured for an energy-autonomous movement of the valve element into the shutdown position.

[0009] By designing the control unit and the delay mechanism as electrical circuits, and by assigning an electrical energy storage device to these circuits, a precisely predefinable and, moreover, essentially independent of environmental conditions, time-delayed control of the electromechanical actuator can be provided. In contrast to the known valve device, boundary conditions such as the supply pressure for the valve device and / or the ambient temperature do not play a significant role in the valve closing process. The electrical energy storage device is designed to provide the electrical energy for operating the control unit and / or the delay mechanism, as well as for controlling the electromechanical actuator during the valve closing process.For the valve shutdown process, it is assumed that the power supply to the valve assembly has already been interrupted, so that no externally supplied energy is available. The amount of energy stored in the electrical energy storage device is dimensioned such that it can provide the energy required for the processing operations in the control unit and / or the delay mechanism necessary to carry out the valve shutdown process, as well as the energy required to actuate the actuator to achieve the shut-off position for the valve element.

[0010] Furthermore, according to the invention, the control device is designed to provide a start signal to the delay element in the absence of a control signal and / or when a supply voltage is switched off, in order to initiate the valve shut-off process. In a normal operating state, the control device has the task of receiving control signals from a higher-level control device, in particular a programmable logic controller (PLC), via direct wiring or a bus system and, depending on the incoming control signals, moving the electromechanical actuator such that the free cross-section of the fluid channel through the valve element is adjusted so that, for example, a predefinable pressure is applied to a fluid consumer connected to the valve device and / or a predefinable fluid flow passes through the connected fluid consumer.Accordingly, the control unit comprises an electrical or electronic circuit section designed to receive control signals and process them into corresponding actuation signals for the electromechanical actuator. This circuit section also includes a detection device configured to recognize a shutdown control signal sent by the higher-level control unit and to generate a start signal for the delay device. Alternatively or additionally, the control unit's circuit section may output a start signal to the delay device if, after a predefined period has elapsed since the last valid control signal, no further valid control signal has been received from the higher-level control unit and / or if the supply voltage to the valve assembly has been switched off.The start signal activates the delay mechanism in order to achieve the desired movement of the valve element into the shut-off position by the electromechanical actuator after a predefinable shutdown condition has occurred, thus setting a subsequent rest state for the valve device.

[0011] In a further development of the invention, the delay means comprises a measuring device configured to provide a shutdown signal to the control unit when a predefinable measurement result is present. The measuring device can be configured to acquire one or more measured values, which, isolated from one another or in predefinable combinations, lead to the output of the shutdown signal by the delay means.

[0012] Preferably, the control device and / or the delay device are provided with adjustment means designed for setting the predefinable measurement result to provide a shutdown signal. The adjustment means can be configured for local setting of the predefinable measurement result on the valve device, in particular in the form of DIP switches or a coding plug. Accordingly, a user can set the valve device to the at least one predefinable measurement result, which is to serve as the criterion for providing the shutdown signal, by appropriately manipulating the DIP switches or the coding plug.Alternatively, the electronic setting of at least one predefinable measurement result can be carried out by user input on a control knob assigned to the control unit, for example designed as a rotary switch, or on another type of similarly usable setting device of the control unit, or by means of the higher-level control unit.

[0013] In an advantageous embodiment of the invention, the measuring device comprises a timer, in particular an adjustable one, configured to provide a shutdown signal to the control unit after a predefinable time interval. For many applications, it is sufficient to ensure fluid supply to the fluid consumer for a predefinable time interval after the process plant or machine tool has been shut down by the higher-level control unit. For this application, the measuring device is configured to record a time interval that begins when the start signal is triggered and ends with the shutdown signal being provided to the control unit. This signal then actuates the electromechanical actuator, moving the valve element into the shut-off position.

[0014] In an advantageous embodiment of the invention, the measuring device comprises a sensor designed to detect a physical measurement value and to provide an electrical measurement signal, dependent on the detected physical measurement value, to the delay element. The detected physical measurement value can be, for example, a mass flow rate of the fluid from the valve assembly to the fluid consumer and / or a temperature, pressure, spatial position of an actuator element, or other physical quantities, which are converted by the associated sensor into an electrical measurement signal that is provided to the delay element to generate the desired shutdown signal when a predefined measurement result is present.Preferably, the measuring device comprises several sensor means and a linkage of electrical measurement signals from these sensor means is provided to generate a shutdown signal, for example, when at least two of the physical measured values ​​have reached or exceeded the respective predetermined measurement result, or to delay the generation of the shutdown signal until, for example, a predetermined measurement configuration is reached. For example, a combination of a time delay with at least one further measured value can be provided, so that a shutdown signal is only output when, on the one hand, the predetermined time duration has been reached or exceeded, and on the other hand, the desired measured value has also been reached.

[0015] Preferably, the control device includes a switching element configured to supply an amount of electrical energy from the electrical energy storage device to the actuating element upon receipt of the shutdown signal, in order to move the valve element into a predefinable operating position at the end of the valve switching process. Preferably, the valve element and / or the actuating element are equipped with at least one preloading element to ensure that at least one operating position of the valve element is maintained without requiring energy. Using the switching element associated with the control device, the valve element can be moved from the operating position to the shutdown position; the energy required for this is supplied by the electrical energy storage device.Preferably, the valve assembly is designed as a bistable valve, so that the valve element can be moved by means of the electromechanical actuator between a first functional position, also referred to as the open position, with a free cross-section of the fluid channel, and a second functional position, also referred to as the closed position, with complete blockage of the fluid channel, which also corresponds to the shut-off position. It is provided that the valve element is held in a sealing contact with the valve seat in the closed position. Furthermore, it is provided that the valve element is held in both functional positions without the supply of external energy, for which purpose the at least one preloading device serves. The preloading device can, for example, be a spring device or a permanent magnet, which exert a holding force on the valve element in the respective functional position.

[0016] In a further embodiment of the invention, the control device and / or the delay element comprises an electrical charging circuit for the electrical energy storage device, which is designed in particular as a capacitor, supercapacitor, or accumulator. With the aid of the electrical charging circuit, the electrical energy storage device can be charged during normal operation of the valve device, i.e., when a control signal and / or a supply voltage is present, either temporarily or continuously, in order to subsequently ensure the desired time-delayed shutdown of the valve device after the supply voltage is switched off and the corresponding control signal is no longer present. Such an electrical energy storage device can be designed using various technologies; advantageous embodiments provide for a design of the electrical energy storage device as a capacitor, supercapacitor, or accumulator.

[0017] In a further embodiment of the invention, the control unit and the delay element are designed as microcontrollers, in particular in a single microcontroller. This allows for a compact and energy-efficient design of the control unit and the delay element. This is especially true when the control unit and the delay element are integrated into a single microcontroller.

[0018] Advantageous embodiments of the invention are shown in the drawing. Here, the drawing shows: Fig. 1 A schematic representation of two different embodiments of the valve device used to control a fluid consumer, Fig. 2 a schematic detailed representation of a first embodiment of a valve device and Fig. 3 a schematic detailed representation of a second embodiment of a valve device.

[0019] One in the Fig. 1. A schematically represented automation system 1, which is designed, for example, to operate a process engineering plant not shown in detail or to operate a processing machine not shown in detail, comprises a control device 2, a bus system 3 and several field devices 4, 5. By way of example, fluid consumers 6, 7, designed as pneumatic cylinders, are assigned to each of the two field devices 4, 5, which are designed to provide linear movements to the process engineering plant or processing machine not shown.

[0020] For the operation of the automation system 1, the control unit 2 is connected to the field devices 4, 5 via the bus system, which can be a fieldbus in particular, to enable the provision of bus commands to the field devices 4, 5. Each of the field devices 4, 5 includes a bus coupler 8, 9, which is configured to convert the bus commands that the control unit 2 provides via the bus system 3. The functional modules 40, 50 of the two field devices 4, 5 are, for example, fluid valves configured to control a fluid flow from a fluid source 41, 51 to the respective connected fluid consumer 6, 7.

[0021] Additionally or alternatively, at least one of the functional modules 40, 50 can be designed, for example, as an input / output module for operating sensor devices not shown in detail and for recording the sensor signals provided by these sensor devices.

[0022] As an example, it is provided that in both field devices 4, 5 the fluid consumers 6, 7 are each connected to two function modules 40: One of the function modules 40, 50 is a conventional valve module 42, 52, which is configured in a known manner to provide a fluid flow to the fluid consumer 6, 7 upon receipt of a corresponding control signal from the bus coupler 8 or 9 via an internal bus system (not shown) or a single-wire arrangement (also not shown) between the bus coupler 8, 9 and the function module 40. Upon receipt of the respective control signal, the valve module 42, 52 enables or interrupts a fluid flow from the respective fluid source 41, 51 to the associated fluid consumer 6, 7.

[0023] The valve assemblies 43 and 53, also designed as functional modules 40 and 50, differ from the valve modules 42 and 52 in that, in addition to the control unit 44 and 54, a [missing information] is integrated into the Fig. The delay means 45, 55 shown in Figures 2 and 3 are provided. The delay means 45, 55 serve to delay the movement of the component in the valve during a valve shutdown process. Fig. 2 and Fig. 3 valve element 22, which is shown and marked with identical reference symbols. As can be seen from the Fig. 2 and Fig. As shown in Figure 3, the valve element 22 is coupled to an electromechanical control device 23, which is exemplified as a solenoid coil and is also referred to as the actuating device 23. The control device 23 can be energized with an electric current when a control signal directed to the control unit 44 or 54 is present, in order to cause movement of the valve element 22 and thus to adjust the free cross-section of a fluid channel 21 formed in the valve body 20. By way of example, a valve seat 24, shown only schematically, is formed in the fluid channel 21 such that when the valve element 22, which is designed, for example, as a ball or spool valve (not shown in detail), rests against the valve seat 24, a complete blockage of the fluid channel 21 is ensured.By way of example, preloading means designed as permanent magnets, not shown in detail, are assigned to the electromechanical actuating device, which are matched to the electromechanical actuating device 23 and the valve element 22 in such a way that the opening position or closed position that can be assumed by the valve element 22 is maintained without the supply of further energy.

[0024] Thus, the valve 19 formed by the valve body 20, the fluid channel 21, the valve element 22, the electrical actuating means 23 and the valve seat 24 represents a bistable working valve which has two self-holding functional positions that can be maintained continuously even without an energy supply.

[0025] In the valve assembly 43, the control unit 44 and the delay element 45 are designed as separate microprocessors on a common printed circuit board 46, wherein the delay element 45 is electrically connected to the control unit 44 in such a way that bidirectional communication between the control unit 44 and the delay element 45 is enabled. Furthermore, an energy storage device 47, exemplified as a supercapacitor, is arranged on the printed circuit board 46. This energy storage device is designed to store electrical energy to an extent sufficient to maintain the function of the control unit 44 and the delay element 45 after the power supply to the printed circuit board 46, which can be provided via electrical lines (not shown), in particular from the bus coupler 8, is switched off.

[0026] As an example, it is provided that the control unit 44, upon switching off the supply voltage, provides a start signal to the delay element 45, which in turn comprises a measuring device designed as a timer (not shown in detail). The measuring device can, for example, be implemented as a discrete area within the microprocessor or run exclusively as a software algorithm within the microprocessor. Upon receiving the start signal from the control unit 44, the measuring device performs a timing operation and, after a predetermined time interval, provides a switch-off signal to the control unit 44.Upon receipt of the shutdown signal at the control unit 44, the control unit 44 supplies an amount of electrical energy stored in the energy storage device 47 to the electromechanical actuator 23 by means of an associated switching device 48, which may be, for example, an electronic switch such as a transistor. This transfers the valve element 22 from a de-energized first operating position to a de-energized second operating position, in which, for example, the fluid channel 21 is blocked. For setting the predefined time interval, an adjustment device, in particular a DIP switch (Dual In-Line Package), not shown in detail, is arranged on the printed circuit board 46, allowing the user to adjust the time interval by moving the individual switches.

[0027] In the valve assembly 53, which also includes a printed circuit board 56 and an energy storage device 47, the control unit 54 and the delay element 55 are arranged in a common microprocessor 58. The microprocessor 58 is electrically connected to sensor inputs 59 and 60 on the printed circuit board 56. For example, the sensor inputs 59 and 60 are connected according to the Fig. 1. A limit switch 61 assigned to the fluid consumer 7 for detecting an end position of the moving part of the fluid consumer 7, and a flow meter 62 for determining a fluid flow into the fluid consumer 7 are assigned. It is provided, by way of example, that the following are Fig.The delay means 55 shown in Figure 3 monitor both a sensor signal from the limit switch 61 and a sensor signal from the flow meter 62 during the valve shutdown process for the valve device 53 and provide a shutdown signal regardless of the time interval elapsed since the arrival of the start signal, provided that a moving part of the fluid consumer 7, in particular a piston rod, has reached a predefinable end position and a predefinable mass flow has been determined with the aid of the flow meter 63.

[0028] By appropriately programming the delay element 55, virtually any combination of logical operations can be performed between signal levels present at sensor inputs 59, 60, and, if applicable, at other sensor inputs not shown, as well as, if necessary, a connection with the timer. This ensures that a flushing process for the fluid consumer 7 connected to the valve assembly 53 is only terminated under precisely defined boundary conditions and is otherwise maintained.

[0029] By designing valve 19 as a bistable valve, the electrical energy stored in the respective energy storage devices 47, 57 is made available to the valve assembly 53 for monitoring the sensor inputs 59, 60, and to both valve assemblies 43 and 53 for operating the control device 44, 54 and the delay element 45, 55. Furthermore, the energy stored in the energy storage devices 47, 57 must be sufficient for at least one switching operation of the electromechanical actuator 23.

[0030] In an embodiment of a valve device not shown, a communication device for wireless reception and / or wireless transmission of control and / or status signals can be assigned to the control device and / or the delay device, with the aid of which communication between neighboring field devices can be carried out for the purpose of a synchronized shutdown after the control device and the supply voltage have been switched off.

Claims

[1] Valve assembly with a valve housing (20) through which a fluid channel (21) is penetrated, in which a valve seat (24) and a valve element (22) which is movably mounted relative to the valve seat (24) are formed, with an electromechanical actuating means (23) for moving the valve element (22) between at least two functional positions to influence a free cross-section of the fluid channel (21) and with a control device (44; 54) which is configured to actuate the actuating means (23) depending on a control signal and which includes a delay means (45; 55) which, in the event of a valve shut-off process, is configured for a time-delayed movement of the valve element (22) into a shut-off position, wherein the control device (44; 54) and the delay means (45;55) are designed as electrical circuits and comprise an electrical energy storage device (47, 57) which is designed for energy-autonomous movement of the valve element (22) into the shut-off position during the valve shut-off process and wherein the control device (44; 54) is designed to provide a start signal to the delay means (45; 55) in the absence of a control signal and / or in the event of a supply voltage being switched off in order to initiate the valve shut-off process.; [2] Valve device according to claim 1, characterized by , that the delay means (45; 55) includes a measuring device which is designed to provide a shutdown signal to the control device (44; 54) when a predefinable measurement result is available. [3] Valve device according to claim 2, characterized by, that the control device (44; 54) and / or the delay device (45; 55) are assigned adjustment means which are designed for adjusting the predefinable measurement result to provide a shutdown signal. [4] Valve device according to claim 2 or 3, characterized by , that the measuring device includes a timer, in particular an adjustable one, which is designed to provide a shutdown signal to the control device (44; 54) after the expiry of a predefinable time period. [5] Valve device according to claim 2, 3 or 4, characterized by , that the measuring device comprises a sensor means (61; 62) which is designed to detect a physical measured value and to provide an electrical measurement signal dependent on the detected physical measured value to the delay means (45; 55). [6] Valve device according to claim 2, 3, 4 or 5, characterized by, that the control device (44; 54) includes a switching means (48; 63) which is designed to provide an amount of electrical energy from the electrical energy storage device (47; 57) to the actuating means (23) upon arrival of the shutdown signal in order to move the valve element (22) into a predeterminable functional position at the end of the valve shutdown process. [7] Valve device according to one of the preceding claims, characterized by that the valve element (22) and / or the actuating means (23) are equipped with at least one preloading means to ensure energy-free maintenance of at least one functional position for the valve element (22). [8] Valve device according to one of the preceding claims, characterized by, that the control device (44; 54) and / or the delay device (45; 55) comprise an electrical charging circuit for the electrical energy storage device (47; 57), which is designed in particular as a capacitor or supercapacitor or accumulator. [9] Valve device according to any one of the preceding claims, characterized by , that the control device (44; 54) and the delay device (45; 55) are designed as microcontrollers, in particular in a common microcontroller (58).

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