Valve arrangement

Abstract

Valve arrangement with a control valve device (12) for the fluidic actuation of a main valve (13) actuated by means of a fluidic pressure medium, wherein the main valve (13) controls a passage for process medium such that in a deactivated state of the main valve (13) the passage is closed and in an activated state is open from an opening pressure of the applied pressure medium, and wherein the control valve device (12) has a supply port (17) connectable to a fluidic pressure source and at least one working port (19) connected to the main valve (13) via a pressure medium line (18) and connectable to the supply port (17) in order to supply pressure medium to the main valve (13), characterized in thatthat the control valve assembly (12) has a pressure control module (22) for regulating the pressure of the pressure medium when the main valve (13) is deactivated to a filling pressure that is above atmospheric pressure and below the opening pressure and is present at the main valve (13).

Description

[0001] The invention relates to a valve arrangement with a control valve device for the fluidic control of a main valve that can be actuated by means of a fluidic pressure medium, wherein the main valve controls a passage for process medium such that in a deactivated state of the main valve the passage is closed and in an activated state it is open from an opening pressure of the applied pressure medium, and wherein the control valve device has a supply port connectable to a fluidic pressure source and at least one working port connected to the main valve via a pressure medium line and connectable to the supply port in order to supply pressure medium to the main valve.

[0002] Valve arrangements for controlling a fluidically actuated main valve have been known for a long time. For example, in the field of process automation, it is common practice to actuate main valves, which can also be called process valves, fluidically. In this case, the main valves are equipped with a fluid-actuated, for example, pneumatically actuated valve actuator, whereby the output motion of the valve actuator is transmitted to a valve element that opens or closes the passage for the process medium formed in the main valve. The simplest embodiment of such main valves is a pure 2 / 2-way main valve, in which the passage is either completely closed or completely open. In other embodiments, a proportional function of the main valve is also conceivable, meaning that the passage can be opened to a defined degree, depending on the required mass flow of process medium.

[0003] DE 602 01 144 T2 discloses a device for controlling a variable pressure. The control valve system described therein has a housing in which two valves are arranged, which can be actuated by means of a double-acting pneumatic actuator, so that the valve elements of the valves can be moved selectively between a closed position and different open positions. A proportional controller is provided to adjust the degree of opening.

[0004] An important parameter of such main valves is the switching time, that is, the time required between a signal sent to the valve assembly to open it and the moment the main valve actually opens. The switching time of fluidically actuated main valves depends on several factors, one of which is the so-called opening pressure, above which the passage is opened. In the example of a single-acting pneumatic cylinder, the spring force of the spring element that pushes the valve element into the closed position must be overcome in order to move the valve element out of its closed position.

[0005] In many applications, switching time has a significant impact on the process quality. A prime example is the semiconductor industry, particularly wafer processing in a wafer processing system. Wafer processing typically involves the sequential use of several different process gases. To maintain consistently high processing quality, the processing time for each gas must be precisely the same. Therefore, the main valve controlling the process gas must have a consistent opening and closing time. Furthermore, the switching time until the main valve opens or is activated must be as short as possible.

[0006] The object of the invention is therefore to create a valve arrangement of the type mentioned above with which the main valves to be controlled can be switched reliably, with functional certainty and as quickly as possible.

[0007] This problem is solved by a valve arrangement having the features of independent claim 1. Further developments of the invention are described in the dependent claims.

[0008] The valve arrangement according to the invention is characterized in that the control valve device has a pressure control module for regulating the pressure of the pressure medium when the main valve is deactivated to a filling pressure that is above atmospheric pressure and below the opening pressure and is present at the main valve.

[0009] The opening pressure required to open the main valve is only reached when the system (valve assembly with main valve), i.e., the control valve assembly, any connected pressure medium line, and any pressure chamber in the main valve, are completely filled with pressure medium or pressure fluid, especially compressed air, and the opening pressure is established. If the system has been previously vented and is at approximately atmospheric pressure, it takes a certain amount of time for this opening pressure to be reached.

[0010] The invention aims to avoid completely venting the system. Instead, when the main valve is deactivated (i.e., when the passage for the process medium is closed), a filling pressure is maintained in the system at the main valve. This means that when the main valve is activated, it is not necessary to fill from a low pressure (e.g., atmospheric pressure) to the opening pressure, but rather from the filling pressure, which is typically significantly higher than atmospheric pressure, to the opening pressure. This allows the opening pressure to be reached much faster, thus reducing the switching time of the main valve. The closer the filling pressure is to the opening pressure, the shorter the switching time. However, a certain "safety margin" should be maintained between the filling pressure and the opening pressure to prevent pressure fluctuations in the system from unintentionally opening the main valve.

[0011] The term pressure control module refers to any module capable of providing the filling pressure, also in the sense of a pressure supply module, for example a lockable pressure or buffer storage tank filled with a fluidic pressure medium, such that the desired filling pressure is provided after the pressure storage tank is opened.

[0012] In a further development of the invention, the control valve device has, in addition to the pressure control module, a control valve fluidically coupled to the pressure control module, via which the feed port can be selectively connected to or disconnected from the working port.

[0013] In a particularly preferred embodiment, the control valve is designed as a switching valve which, in a first switching position, connects the supply port to the working port and, in a second switching position, disconnects the working port from the supply port. In this embodiment, the switching valve can, for example, be designed as a 2 / 2-way valve.

[0014] In a particularly preferred embodiment, the switching valve, in addition to the supply port and at least one working port, has at least one vent port, wherein in the second switching position the working port is connected to the vent port and the fluidically coupled pressure control module provides the filling pressure via the vent port. This design prevents venting to the atmosphere via the vent port, since, with the main valve deactivated, pressure medium is supplied up to the filling pressure. Such a switching valve can be configured, for example, as a 3 / 2-way valve or, with two working ports and two vent ports, as a 5 / 2-way valve.

[0015] In a further development of the invention, the pressure control module is designed as a pressure control valve, in particular a proportional pressure control valve. Advantageously, an electronically controlled proportional pressure control valve is provided. With the proportional pressure control valve, especially in its electronic version, it is possible to vary the pressure between atmospheric pressure and the operating pressure in a simple and quick manner, thus also allowing the filling pressure to be set precisely. A directly actuated pressure control valve, for example with a piezoelectric valve element, is also suitable as a pressure control valve, enabling very short switching times.

[0016] Alternatively, it is conceivable that the pressure control module is designed as a throttle valve, in particular an air supply throttle valve.

[0017] In a further development of the invention, the pressure control module has a regulator supply port on a regulator working port that can be coupled to or is coupled to the regulator supply port, wherein the regulator supply port is connected either to the control valve, in particular to the vent port of the switching valve, or directly to the main valve via the pressure medium line without the intermediate control valve. It is therefore possible for the control valve assembly to comprise a combination of pressure control module and control valve, or simply the pressure control module without a control valve. In the latter case, the regulator supply port corresponds to the supply port and the regulator working port to the working port of the control valve assembly.Alternatively, it is also conceivable to connect a pressure accumulator or buffer tank upstream of the venting port of the control valve, the outlet port of which can be shut off, for example by means of a shut-off valve (2 / 2-way valve), is connected to the venting port.

[0018] In a particularly preferred embodiment, the control valve assembly is a control valve assembly designed separately from the main valve.

[0019] In a particularly preferred embodiment, the control valve assembly is arranged at a distance from the main valve, and the working port is connected to the main valve via the pressure medium line, which is preferably designed as a hose. Since the main valve becomes relatively warm or even hot in various applications, particularly due to preheated process gases, it is necessary to arrange the heat-sensitive control valve assembly at a distance from the main valve to ensure the operational reliability of the control valve assembly.

[0020] In a further development of the invention, the valve arrangement comprises a main valve that can be actuated by means of a fluidic pressure medium. Advantageously, the main valve has a fluid-actuated valve actuator that controls a valve element arranged in a valve assembly of the main valve, which in turn can selectively open or close the passage for process medium in the main valve.

[0021] The invention further relates to a method for operating a valve arrangement, with a control valve device for the fluidic actuation of a main valve actuated by means of a fluidic pressure medium, wherein the main valve controls a passage for process medium such that in a deactivated state of the main valve the passage is closed and in an activated state is open from an opening pressure of the applied pressure medium, and wherein the control valve device has a supply port connectable to a fluidic pressure source and at least one working port connected to the main valve via a pressure medium line and connectable to the supply port in order to supply pressure medium to the main valve, the method comprising the following steps: - Pressurizing the main valve in its deactivated state with pressure medium supplied via a pressure control module of the control valve device up to a filling pressure above atmospheric pressure and below the opening pressure, - Switching the control valve device to connect the feed port to the working port, thereby allowing pressurized pressure medium to reach the main valve, - Activating the main valve, which opens the passage for the flow of process medium from an opening pressure.

[0022] The prior art and preferred embodiments of the invention are illustrated in the drawing and are explained in more detail below. The drawing shows: Fig. 1 a schematic representation of a first embodiment of a valve arrangement according to the prior art, Fig. 2 a schematic representation of a second embodiment of a valve arrangement according to the prior art, Fig. 3 a first embodiment of the valve arrangement according to the invention in schematic representation, Fig. 4 a second embodiment of the valve arrangement according to the invention in schematic representation and Fig. 5 a third embodiment of the valve arrangement according to the invention in schematic representation.

[0023] The Fig. 1 and Fig. Figure 2 shows different design variants of conventional valve arrangements 11 according to the state of the art.

[0024] The prior art valve arrangement 11 shown in the figure as an example and schematic has a control valve device 12 for the fluidic control of a main valve 13 which can be actuated by means of a fluidic pressure medium.

[0025] Compressed air is particularly suitable as a fluidic pressure medium.

[0026] Although not shown, a main valve 13 could be designed as follows: The main valve has a valve assembly with a through-channel extending between a first and a second port through the valve assembly. This channel has a flow orifice that can be selectively opened or closed by a valve element movable between an open and a closed position. The opening and closing movement of the valve element is generated by a valve actuator mounted on the valve assembly, which is designed as a fluidically actuated valve actuator. Such a fluidically actuated valve actuator can, for example, be designed like a single-acting pneumatic cylinder. In the example shown, a valve actuator with a normally closed function is suitable; that is, when the main valve is deactivated, the passage for the process medium is blocked or closed.This can be achieved, for example, by an actuating spring acting on the valve element, which pushes the valve element into the closed position. To activate the main valve, i.e., to move the valve element from the closed position to the open position, thereby allowing the flow of process medium between the two ports, the valve actuator requires compressed air. This forces the valve element out of the closed position against the spring force of the actuating spring, thus opening the main valve. A characteristic feature of this process is the opening pressure, determined by the spring force of the actuating spring, which must be overcome by the compressed air to open the valve element against the spring force of the actuating spring.

[0027] In certain application areas, particularly semiconductor manufacturing, such as wafer processing in a wafer processing system, the main valve must meet various requirements, conditions, or parameters. During wafer processing, the wafer is typically treated with different process gases.

[0028] The processing time with the different process gases should always be the same. This means that the switching time of the main valve, i.e., the opening and closing process of the main valve, should always be the same. Another criterion is that the switching time, i.e., the time calculated from the moment the signal is sent to the control valve until the main valve opens by reaching the opening pressure, should be as short as possible.

[0029] The switching time depends on several factors, including the switching time of the control valve device 12, the pressure currently present at the main valve before activation of the main valve, and the length of the pressure medium line between the control valve device 12 and the main valve 13.

[0030] As particularly in Fig. As shown in Figure 1 of the conventional valve arrangement 11, the control valve assembly 12 has a single control valve 14, which in the example shown is designed as a switching valve. In the example shown, a 3 / 2-way valve is provided. The control valve assembly 12 has a supply port 17 connected to a fluidic pressure source 15 via a supply line 16 and at least one working port 19 connected to the main valve 13 via the pressure medium line 18 and connectable to the supply port 17. In the case of the arrangement shown in Figure 11, the control valve assembly 12 has a single control valve 14, which in the example shown is designed as a switching valve. Fig. In the embodiment shown in Figure 1, the pressure medium line 18 is a working line leading from the working port 19 to the main valve 13, for example in the form of a hose. Furthermore, the supply port 17 and the working port 19 of the control valve assembly 12 are identical to the supply port 17 and working port 19 of the control valve 14.

[0031] In the case of the control valve 14, which is designed as a 3 / 2-way valve, it has a vent port 20 in addition to the supply port 17 and the working port 19. Here, too, as with the main valve 13, the control valve 14 is designed as a normally closed (NC) control valve. This means that in the deactivated state, the control valve 14 assumes a first switching position in which the working port 19 is disconnected from the supply port 17. By actuating or switching the control valve 14, it can be switched to a second switching position in which the supply port 17 is connected to the working port 19 to supply pressure medium from the pressure source 15, at an operating pressure of, for example, 6 bar, to the main valve 13.

[0032] In the first switching position of the control valve 14, the working port 19 is also connected to the vent port 20, whereby the main valve 13 is vented via the vent port 20, so that a pressure is present at the main valve 13 which is generally in the range of atmospheric pressure. Furthermore, a silencer 21 is also connected to the vent port 20.

[0033] As particularly in Fig. As shown in Figure 1, the switching time for the main valve, i.e., the time from the signal transmission to the control valve 14 for switching from the first to the second switching position until the main valve is activated and opens, depends significantly on the switching time of the control valve for switching from the first to the second switching position and on the volume to be filled until the opening pressure is established. The volume to be filled depends on the length and diameter of the pressure medium line, as well as on the dimensions of the working chamber of the main valve to be filled; in the case of a single-acting pressure cylinder, it depends on the spring force of the return spring.

[0034] The Fig. Figure 2 shows a second embodiment of a valve arrangement 11 according to the prior art. The valve arrangement 11 according to the second embodiment is essentially identical in construction to the first embodiment. Only the pressure medium line 18, i.e., the working line between the working port 19 of the control valve 14 and the main valve, has been shortened, thereby reducing the volume to be filled and therefore shortening the switching time.

[0035] However, this measure is not sufficient to achieve a significant reduction in switching time; in particular, such valve arrangements 11 are only moderately or not at all suitable for wafer processing in a wafer processing plant.

[0036] The Fig. Figure 3 shows a first embodiment of the valve arrangement 11 according to the invention, with which the switching time is reduced compared to the ones described in the Fig. 1 and Fig. The length of the conventional valve arrangements 11 shown in the prior art could be shortened.

[0037] As particularly in Fig. As shown in Figure 3, the same type of main valve 13 is provided here, for example one as already described in connection with the previously described design variants.

[0038] A key aspect of the invention is that the control valve device 12 has a pressure control module 22 for regulating the pressure of the pressure medium when the main valve 13 is deactivated to a filling pressure that is above atmospheric pressure and below the opening pressure and is present at the main valve.

[0039] In the Fig. In the embodiment shown in Figure 3, a combination of control valve 14 and pressure control module 22 is shown. The pressure control module 22 ensures that the main valve 13 is not vented in the first switching position, i.e., in the switching position in which the working port 19 and the vent port 20 are connected. On the contrary, the pressure control module 22 ensures that the filling pressure is present at the main valve 13, so that when the control valve 14 switches to the first switching position, significantly less volume needs to be filled, so that the opening pressure is reached much sooner and thus the switching time is reduced.

[0040] According to the first embodiment, the pressure control module 22 is designed as a pressure control valve, in particular a proportional pressure control valve, which in the illustrated example is electronically controlled. The pressure control valve has a regulator feed port 23, which is connected to the pressure source 15 via a regulator feed line, for example by connection to the feed line 16. The pressure control module 22 also has a regulator working port 24 which is fluidically coupled to the vent port 20 of the control valve 14. Thus, pressure medium from the pressure source 15 reaches the pressure control module 22, which, in the case of a proportional pressure control valve, specifies a precise filling pressure with which the volume is pre-filled up to the main valve 13, so that the filling pressure is present at the main valve 13.

[0041] Typical opening pressures for a main valve at an operating pressure of 6 bar are, for example, 4 to 4.5 bar, with the filling pressure then ranging from 2.5 to 3.5 bar. However, these figures are purely examples; the opening pressure, and consequently the filling pressure, can deviate from these values.

[0042] In the example shown, a control valve device 12 is equipped with a control valve 14 in the form of a switching valve in combination with a pressure control module 22, in particular a proportional pressure control valve, wherein the feed port 17 of the control valve device 12 does not coincide with the regulator feed port, since in the example shown the feed channel is divided into a regulator feed channel and a control valve feed channel.

[0043] The Fig. Figure 4 shows a second embodiment of the valve arrangement 11 according to the invention. In this example, the control valve assembly 12 is equipped only with the pressure control module 22. No control valve 14 is provided here. Thus, the feed port 17 of the control valve assembly corresponds to the controller feed port 23, and the working port 19 of the control valve assembly 12 corresponds to the controller working port 24. Advantageously, a proportional pressure control valve is again provided here, which is electronically controlled and, for example, as a directly controlled proportional pressure control valve, switches very quickly, particularly as a result of at least one valve element designed as a piezoelectric element. This allows the pressure to be raised very quickly from a filling pressure set by the proportional pressure control valve, which is present at the main valve in the deactivated state, to the operating pressure.

[0044] The Fig.Figure 5 shows a third embodiment of the valve arrangement 11 according to the invention. The third embodiment is designed similarly to the first embodiment, with the difference that the pressure control module 22 is not a pressure control valve, in particular a proportional pressure control valve, but a throttle valve in the form of an air intake throttle valve. Here, too, a regulator supply port 23 and a regulator working port 24 are provided.

[0045] A characteristic feature of such an air supply throttle valve is a bypass line 25, which, however, is closed in the flow direction from the regulator supply port 23 to the regulator working port 24 by means of a check valve 26, meaning that no pressure medium can reach the regulator working port 24 via the bypass line 25, but the bypass line 25 would be available for venting.

[0046] Here too, the regulator working port 24 of the throttle valve is connected to the vent port 20 of the control valve and ensures that the volume from the regulator working port to the main valve is filled with pressure medium at a pressure equal to the filling pressure.

[0047] The procedure for operating the valve assembly is as follows: First, the main valve 13, in its deactivated state, is pressurized with pressure medium supplied via the pressure control module 22 of the control valve device 12 until a filling pressure is above atmospheric pressure and below the opening pressure.

[0048] The control valve assembly is then switched to connect the feed port 17 to the working port 19, allowing pressurized pressure medium to reach the main valve 13. The main valve is then activated by opening the passage for the process medium once a certain opening pressure is reached.

[0049] According to the first embodiment, the main valve is pressurized with filling pressure via the pressure control module 22, which is designed as a proportional pressure control valve and whose control working port 24 is connected to the vent port 20 of the control valve 14. The control valve assembly is switched by switching the control valve 14 from the first switching position to the second switching position, in which the supply port 17 is connected to the working port 19 and pressure medium at operating pressure flows to the main valve 13.

[0050] According to the second embodiment, the main valve 13 is actuated in its deactivated state via the pressure control module 22, which is designed as a proportional pressure control valve, whereby the switching of the control valve device 12 is carried out here by raising the pressure of the proportional pressure control valve.

[0051] According to the third embodiment, the main valve 13 is pressurized with filling pressure via the throttle valve, whose regulator working port 24 is connected to the vent port 20 of the control valve 14. The control valve assembly 12 is switched by switching the control valve 14 from the first to the second switching position.

[0052] All three described embodiments of the control valve arrangement according to the invention have in common that a filling pressure is present at the main valve 13, so that for the subsequent activation of the main valve only the difference between the opening pressure and the filling pressure has to be overcome, i.e. significantly less volume has to be refilled, which reduces the switching time overall.

Claims

[1] Valve arrangement with a control valve device (12) for the fluidic control of a main valve (13) actuated by means of a fluidic pressure medium, wherein the main valve (13) controls a passage for process medium such that in a deactivated state of the main valve (13) the passage is closed and in an activated state is open from an opening pressure of the applied pressure medium, and wherein the control valve device (12) has a supply port (17) connectable to a fluidic pressure source and at least one working port (19) connected to the main valve (13) via a pressure medium line (18) and connectable to the supply port (17) in order to supply pressure medium to the main valve (13), characterized by, that the control valve device (12) has a pressure control module (22) for regulating the pressure of the pressure medium when the main valve (13) is deactivated to a filling pressure that is above atmospheric pressure and below the opening pressure and is present at the main valve (13). [2] Valve arrangement according to claim 1, characterized by , that the control valve assembly (12) has, in addition to the pressure control module (22), a control valve (14) fluidically coupled to the pressure control module (22), via which the feed port (17) can be selectively connected to or disconnected from the working port (19). [3] Valve arrangement according to claim 2, characterized by , that the control valve (14) is designed as a switching valve which in a first switching position separates the working port (19) from the supply port (17) and in a second switching position connects the supply port (17) to the working port (19). [4] Valve arrangement according to claim 3, characterized by, that the switching valve has, in addition to the feed port (17) and at least one working port (19), at least one vent port (20), wherein in the second switching position the working port (19) is connected to the vent port (20) and the fluidically coupled pressure control module (22) provides the filling pressure via the vent port (20). [5] Valve arrangement according to one of the preceding claims, characterized by , that the pressure control module (22) is designed as a pressure control valve, in particular a proportional pressure control valve. [6] Valve arrangement according to any one of claims 1 to 4, characterized by , that the pressure control module (22) is designed as a throttle valve, in particular an air supply throttle valve. [7] Valve arrangement according to one of the preceding claims, characterized by, that the pressure control module (22) has a regulator supply port (23) and a regulator working port (24) that can be coupled to or connected with the regulator supply port (23), wherein the regulator supply port (23) is connected either to the control valve (14), in particular to the vent port of the switching valve, or directly to the main valve (13) via the pressure medium line (18) without the control valve (14) being connected. [8] Valve arrangement according to one of the preceding claims, characterized by , that the control valve assembly (12) is a control valve assembly designed separately from the main valve (13). [9] Valve arrangement according to claim 8, characterized by , that the control valve assembly is arranged at a distance from the main valve (13) and the working connection (19) is connected to the main valve (13) via the pressure medium line (18) which is designed in particular as a hose line. [10] Valve arrangement according to one of the preceding claims, characterized by a main valve (13) that can be actuated by means of a fluidic pressure medium. [11] Method for operating a valve arrangement, in particular a valve arrangement according to one of features 1 to 10, wherein the valve arrangement has a control valve device (12) for fluidic actuation of a main valve (13) actuated by means of a fluidic pressure medium, wherein the main valve (13) controls a passage for process medium such that in a deactivated state of the main valve (13) the passage is closed and in an activated state is open from an opening pressure of the applied pressure medium, and wherein the control valve device (12) has a supply port (17) connectable to a fluidic pressure source and at least one working port (19) connected to the main valve (13) via a pressure medium line (18) and connectable to the supply port (17), the method comprising the following steps: - Pressurizing the main valve (13) in its deactivated state with pressure medium supplied via a pressure control module (22) of the control valve assembly (12) up to a filling pressure above atmospheric pressure and below the opening pressure, - Switching the control valve device (12) to connect the feed port (17) to the working port (19), thereby allowing pressure medium (22) under operating pressure to reach the main valve (13), - Activation of the main valve (13) by opening the passage to allow the flow of process medium from an opening pressure.

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