Method for determining correction value of control device for controlling valve

Abstract

The invention relates to a method for determining a correction value of a control device of a control valve, said control valve controlling a fluid flow flowing through a chamber and determining a correction value of a control device of a control valve. The closure member of the control valve is arranged by the control device in mutually different positions with respect to the flow opening for the fluid flow by means of an adjustment drive of the control valve, an encoder, in particular of the control valve, is provided, and each position of the closure member corresponds to an encoder value of the encoder, wherein pressure values, in particular representative of the fluid in the chamber, are measured at mutually different positions of the closure component by means of pressure sensors, and wherein the position of the closure component when the maximum value of the pressure values is measured is identified as a minimum flow position of the closure component by the control device, and determine the correction value as a function of the encoder value when the minimum flow position is identified.

Description

Technical Field

[0001] The invention relates to a method for determining a correction value for a control device of a control valve and also to a method for controlling the position of a closing element of a control valve using the correction value determined in this way. Background Art

[0002] Control valves are used to control the flow of fluid through a chamber, in particular in so-called vacuum technology. They can then be used to adjust the amount of fluid flowing through the chamber per unit time. Corresponding control valves are known in the prior art by publicly available prior use. They have a closing member and an adjusting drive for the closing member. The corresponding position of the closing member is determined by means of an encoder. The regulating device uses the encoder value output by the encoder as information about the current position of the closing member. If the closing member is in the minimum flow position, only the corresponding minimum fluid still flows through the flow opening. In the minimum flow position, the closing member can completely close the flow opening so that the minimum flow does not correspond to any flow. However, in the minimum flow position, a certain minimum flow is still possible. If more fluid flows through the chamber, the closing member is brought to a correspondingly wider open position by the adjusting drive, at which position, correspondingly more fluid flows through the chamber per unit time.

[0003] The encoder value reflects the corresponding position of the closing element. Ideally, the encoder value is zero in the minimum flow position. However, in practice, this is not the case when the control valve is put into operation or when the control valve must be maintained or when a component or the entire control valve must be replaced. As a rule, the encoder therefore does not necessarily output a zero value in the minimum flow position, but another value. Summary of the invention

[0004] It is therefore an object of the present invention to provide a method for determining a correction value by means of which this problem can be solved.

[0005] To this end, the invention proposes a method according to claim 1 .

[0006] Therefore, the present invention provides a method for determining a correction value of a control device of a control valve, wherein the control valve controls a fluid flow flowing through a chamber, and a closing component of the control valve is set at different positions relative to a flow opening for the fluid flow by the control device with the help of an adjusting drive device of the control valve, wherein an encoder, in particular of the control valve, is set and each position of the closing component corresponds to an encoder value of the encoder, wherein pressure values, in particular representing the fluid in the chamber, are measured at different positions of the closing component with the help of a pressure sensor, wherein the position of the closing component when the maximum value of the measured pressure value is identified by the control device as the minimum flow position of the closing component, and the correction value is determined by the encoder value when the minimum flow position is identified.

[0007] For example, the encoder value when the minimum flow position is identified can be determined as the correction value. The correction value is then equal to the encoder value when the minimum flow position is identified. However, the encoder value and the correction value when the minimum flow position is identified can also be in another mathematical relationship.

[0008] The basic idea of ​​the invention is therefore to measure the pressure in different positions of the closure member using a pressure sensor, wherein the corresponding encoder value reflects the corresponding position of the closure member. The minimum flow position of the closure member (which may also be referred to as the maximum closed position of the closure member) is identified as the position when the pressure value reaches its maximum value. A correction value is then determined based on the encoder value output by the encoder in the minimum flow position. The correction value may also be referred to as an offset.

[0009] Therefore, the method according to the invention is a calibration process, which is preferably carried out at least once during commissioning, recommissioning or after maintenance or replacement of parts of the control valve or parts of the entire device (in particular the regulating drive or the encoder). During the execution of the method, it is then determined which encoder value is output by the encoder in the minimum flow position of the closure member. Ideally, the encoder value is equal to zero in the minimum flow position. The correction value can then also be set to zero. However, usually, another encoder value is output by the encoder in the minimum flow position of the closure member, from which the correction value can be determined in the subsequent operation of the control valve in a manner that will be further explained below.

[0010] The closure member is a part of the regulating valve for completely or partially closing or opening the flow opening. In principle, the closure member can be shaped in various ways. However, in a preferred embodiment, the closure member is a plate-shaped closure member, which may also be referred to as a closure plate or valve plate.

[0011] The flow opening that is closed or opened to a corresponding degree by the closure member depending on the position of the closure member can be located in the housing of the control valve. However, for example, it is also feasible that the flow opening is located in the chamber wall of the chamber or in the fluid line connected to the chamber. In the minimum flow position, the closure member can seal or close the flow opening completely, but can still allow certain or minimum flow. Those skilled in the art can design this point according to their needs for the corresponding application. In any case, the minimum flow position can also be called the maximum closed position of the closure member.

[0012] The regulating drive of the control valve can be designed, for example, as an electric servomotor, with which the closing element can be brought into its different positions relative to the flow opening. However, the regulating drive can also be a pneumatic, hydraulic or other motor drive. Mixtures of these drive types known per se are also possible.

[0013] The encoder can but does not have to be directly a part of the control valve, in particular the regulating drive. For example, the encoder can be integrated into the regulating drive or placed on it, or the corresponding position of the closure member can be determined and reproduced in another way. But it can also be a simulated digital encoder that measures in a step-by-step manner (i.e., the encoder step-by-step manner). Therefore, in the case of a digital design, the encoder value can be an integer sequence. But for an encoder of analog measurement, the encoder value can also represent the corresponding position of the closure member as a rational number, i.e., with decimal places. In any case, it is preferably provided that each position of the closure member corresponds exactly to an encoder value of the encoder. The encoder can also be referred to as a measured value encoder, or as a rotary encoder in the case of a rotary encoder. Therefore, the encoder value can also be referred to as a measured value encoder value or a rotary encoder value.

[0014] The fluid flowing through the chamber to be regulated by the regulating valve can be a pure gas flow, but also a pure liquid flow, or also a mixture thereof.

[0015] The pressure value measured by the pressure sensor is preferably a pressure value representing the fluid in the chamber. The pressure value can be measured directly in the chamber, but can also be measured in a pipeline connected to the chamber or in another suitable location. In any case, the pressure value preferably represents the current pressure in the chamber.

[0016] When the method is performed, the position of the closure member should at least be a relevant variable that mainly affects the corresponding pressure value. Therefore, the pressure value should be clearly related to or affected by the corresponding position of the closure member. In other words, the position of the closure member should be an important and clearly identifiable influencing variable for the pressure measured by means of a pressure sensor. According to a preferred embodiment of the method of the present invention, during the execution of the method according to the present invention for determining the correction value, the position of the closure member is the only influencing variable for the pressure measured by means of a pressure sensor. In this sense, it is preferably provided that during the execution of the entire method, the fluid flows permanently through the chamber, and the change in the position of the closure member is the only variable that changes during the method and affects the flow of the fluid.

[0017] The control device receives the encoder value from the encoder and the pressure value from the pressure sensor. Usually, the control device is initially used to control the adjustment drive according to the specifications of the closing element, that is, the respectively desired position, taking into account the encoder value, so that the closing element is brought to the respectively desired position. However, in the method according to the invention, the control device is also used to carry out the method according to the invention and thereby determine the correction value. The control device can be directly part of the control valve. However, it can also be an external control device that is connected to the control valve and the pressure sensor accordingly.

[0018] Preferably, provision is made that during the implementation of the method according to the invention for determining a correction value, the fluid is pumped through the flow regulating valve and the chamber and the flow opening by means of a pump. The regulating valve is preferably located between the pump and the chamber. The regulating valve can be arranged, for example, on a fluid line extending between the pump and the chamber, or can also be arranged directly between the pump and the chamber.

[0019] In principle, it is considered sufficient to carry out the method for determining the correction value according to the invention once. However, in particular, if the closing member has a certain gap or it is a digital encoder that only outputs integer encoder values, it can also be shown that the method for determining the correction value is carried out once when the control valve is opened and once when the control valve is closed. A preferred variant of the invention provides that the method is carried out for the first time and then for the second time, wherein the position of the closing member is passed through in a first direction for the first time and the position of the closing member is passed through in a second direction opposite to the first direction for the second time, and the first correction value is determined for the first time, the second correction value is determined for the second time, and the correction value is determined based on the first correction value and the second correction value. In this case, the correction value is determined based on two correction values ​​(i.e. the first correction value and the second correction value), which can also be said to be the final correction value, which is then taken into account when operating the control valve (as will be described below). In order to calculate the final correction value, for example, an average value can be calculated based on the first correction value and the second correction value. However, it is also conceivable to simply adopt the smaller or larger value of the above two correction values ​​as the final correction value. If the method according to the invention is operated with a digital encoder whose encoder values ​​are always integers, the final correction value calculated in this way can also be rounded up or down to the next integer accordingly.

[0020] In principle, it is feasible that in the method according to the invention for determining the correction value, all possible positions of the closure member are traversed in order to ensure that the minimum flow position and the corresponding encoder value are found. However, there is usually enough prior information so that the person skilled in the art only needs to traverse the predetermined position range of the closure member in order to reliably also include the minimum flow position. Such prior information can be, for example, the encoder value at the minimum flow position of the previously used control valve when replacing the control valve or the parts of the control valve. However, it is also feasible that the control valve has a starting position predetermined by a stopper or in other ways, and when executing the method, starting from the starting position of the closure member, the closure member is arranged in different positions relative to the flow opening for fluid flow. Instead of the stopper, the starting position specified in other ways can be, for example, a position marked on the housing of the control valve, etc.

[0021] The method according to the invention for determining a correction value can be used for control valves of different designs. The control valve can then be, for example, a so-called butterfly valve, in other words a butterfly valve. It can therefore be provided that the closing component is a valve plate, which can be pivoted by an adjustment drive about a pivot axis extending along the valve plate, wherein the valve plate protrudes beyond the pivot axis on mutually opposite sides of the pivot axis. In the case of a so-called butterfly valve, it can also be said that the pivot axis extends in the plane of the valve plate, wherein the term valve plate plane is of course a certain simplification due to the spatial extent of the valve plate.

[0022] The method according to the invention for determining the correction value is implemented with a control valve, which can also be a swing valve, for example. It can therefore be provided that the closing component is a valve plate, which can be pivoted by an adjustment drive about a pivot axis extending parallel to the normal of the valve plate. In a swing valve, the pivot axis usually extends at the edge next to the valve plate. The valve plate can be connected to the rotation axis via a pivot arm. However, the bearing of the pivot axis can also be arranged directly on the edge of the valve plate.

[0023] In the control valves mentioned so far in the form of butterfly valves and swing valves, the different positions of the closing member are always different angular positions. This is not necessarily the case. The method according to the invention for determining the correction value can also be used, for example, in valves in which the closing member is arranged in a linearly displaceable manner. In such a control valve, the closing member is then pushed back and forth between different positions in which it more or less closes the flow opening. For this purpose, the closing member can be arranged, for example, on a guide, in particular a linear guide or the like.

[0024] If the correction value is determined, it can then be used in the above-described operation of the control valve, or in other words, in the normal operation of the control valve, wherein the fluid flow through the flow opening is correspondingly adjusted by the corresponding position of the closing member. In the method according to the invention for regulating the position of the closing member of the control valve by means of a control device, this operation or in other words the normal operation of the control valve provides that the corresponding position of the closing member to be controlled is determined by the control device taking into account the correction value determined by the method according to the invention described above. This method can also be referred to as a method for controlling the position of a control valve, in particular if no other controlled variables need to be taken into account in addition to the pure provision of the desired position of the closing member.

[0025] In the method, then, in operation or normal operation of the control valve, the minimum flow position is preferably an end position which is not exceeded in contrast to the method according to the invention for determining the correction value. In this operation or normal operation of the control valve, it is preferably provided that the closure member only reaches positions in which the corresponding encoder value is greater than or equal to the correction value or the corresponding encoder value is less than or equal to the correction value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further features and details of preferred embodiments of the method according to the invention are explained below by way of example using exemplary embodiments.

[0027] Figure 1 A schematic diagram shows a device having a chamber and a control valve, with which the method according to the invention can be carried out;

[0028] Figure 2is a schematic longitudinal section through a control valve in the form of a butterfly valve, with which the method according to the invention can be implemented;

[0029] Figure 3 yes Figure 2 A schematic cross-sectional view of the control valve in the region of the closing member;

[0030] Figure 4 is a view of the relationship between pressure and encoder value without the need for correction;

[0031] Figure 5 Shown in Figure 4 The position of the closed component when the encoder value in is 0;

[0032] Figure 6 Shown in Figure 4 The position of the closed component when the encoder value in is 10;

[0033] Figure 7 Similar to Figure 4 The diagram shows an example of a need for correction;

[0034] Figure 8 Shown in Figure 7 The position of the closed component when the encoder value in is 2;

[0035] Fig. 9 Shown in Figure 7 The position of the closed component when the encoder value in is 4;

[0036] Fig.10 Shown in Figure 7 The position of the closed component when the encoder value in is 12;

[0037] Fig.11 is a diagram of pressure versus encoder value to illustrate the method for determining a correction value according to the present invention;

[0038] Fig.12 Shown in Fig.11 The position of the closing member of the regulating valve when the encoder value in is 0;

[0039] Fig.13 Shown in Fig.11 The position of the closed component when the encoder value in is 4;

[0040] Fig.14 Shown in Fig.11 The position of the closed component when the encoder value in is 8;

[0041] Fig.15 is a diagram of the relationship between pressure and encoder value according to a second variant of the method for determining a correction value according to the invention;

[0042] Figures 16 to 18 It is a schematic diagram of a control valve in the form of a swing valve;

[0043] Figures 19 to 21 is a schematic diagram of a control valve having a movably mounted closing member;

[0044] Fig. 22 is a diagram of the relationship between pressure and encoder value to illustrate a method for controlling the position of a closing member of a control valve using a correction value;

[0045] Fig.23 is Fig. 22 A diagram showing the position of the closing member when the encoder value in is 4;

[0046] Fig.24 is Fig. 22 Illustration of the position of the closing member when the encoder value in is 14. DETAILED DESCRIPTION

[0047] Figure 1 The schematic diagram of a device is a method for determining a correction value K according to the invention and a method for controlling the position of a closing member 3 of a control valve 1 according to the invention can be performed. The device comprises a chamber 2. Here, it can be, for example, a processing chamber, a transfer chamber or another chamber. In general, the device is preferably used in the field of vacuum technology, but this does not necessarily have to be the case. This also applies to the method according to the invention. Vacuum technology refers in particular to working at a pressure level less than or equal to 0.001 mbar (millibar) or 0.1 Pascal. However, when working at a pressure below normal pressure (i.e. below 1 bar), it can already be said to be vacuum technology.

[0048] Here in this example, the control valve 1 is arranged on the fluid line 17 between the chamber 2 and the pump 9. The regulating drive 5 is used to adjust the closing member 3 of the control valve 1. The regulating drive 5 is controlled by the control device 4. For this purpose, the control device 4 is also connected to a pressure sensor 8 for determining a pressure value P, here a pressure value P representing the pressure in the chamber 2. A fluid, in particular a gas, can flow into the chamber 2 through the flow regulating valve 10 and the corresponding fluid line 17. The pump 9 generates the negative pressure required for this. That is, the pump is a suction pump 9, which sucks the fluid, in particular a gas, through the flow regulating valve 10 and the chamber 2 and the flow opening 6 of the control valve 1. For the sake of completeness, it should be pointed out that the pressure sensor 8 can also be arranged on the fluid line 17 between the chamber 2 and the control valve 1 in order to measure the pressure value P representing the pressure in the chamber 2. Other arrangements of the pressure sensor 8 are also feasible in principle.

[0049] Figure 2A schematic longitudinal section through a control valve 1 is shown in the form of a so-called butterfly valve or, in other words, a butterfly valve. The closing component 3 is a valve plate which can be pivoted by means of an adjusting drive 5 about a pivot axis 13 extending along the valve plate. The valve plate always protrudes beyond the pivot axis 13 on mutually opposite sides of the pivot axis 13. Such so-called butterfly valves are known per se and require no further explanation. Figure 2 and Figure 3 In the minimum flow position shown, or in other words, in the maximum closed position, the closing member 3 (i.e., the valve plate here) is arranged in the flow opening 6 so that the closing member closes the flow opening 6 to the maximum extent, i.e., in other words, only a minimum fluid flow is possible. According to an embodiment of the control valve 1, the closing member 3 can completely close or seal the flow opening 6 in the minimum flow position, so that the fluid flow is equal to zero. However, a control valve 1 is also feasible, that is, as far as the control valve is concerned, a certain minimum value of fluid flow is still allowed through the flow opening 6 in the minimum flow position.

[0050] In this embodiment of the control valve 1, the flow opening 6 is located in the valve housing 16 of the control valve 1. However, as explained at the beginning, this is not necessarily the case. It is also possible that the flow opening 6 is located directly on the chamber wall of the chamber 2 or on another housing, such as the fluid line 17.

[0051] In order to pivot the valve plate or the closing member 3 about the pivot axis 13, an adjusting drive 5 is provided in the control valve 1, which is correspondingly controlled by the control device 4. As in this embodiment, the adjusting drive can be, for example, an electric motor, but can also be other suitable adjusting drive 5 known per se in the prior art.

[0052] In accordance with Figure 2 In the longitudinal section of the closure member 3, an encoder 7 can also be seen, which determines the respective position of the closing member 3 and forwards it to the regulating device 4. The encoder 7 can, for example, directly access the pivot shaft 13 rotated by the regulating drive 5 to determine its position. Here, in this embodiment, the encoder 7 is shown as an additional component connected to the regulating drive 5. Of course, the encoder 7 can also be integrated directly into the regulating drive 5. However, it is also possible to use an encoder 7 completely separate from the regulating drive 5 or even completely separate from the regulating valve 1 to determine the position of the closing member 3.

[0053] exist Figure 3 A stopper 15 is also schematically shown, which may be present optionally, but need not be present. If the closure member 3 is pivoted so that it contacts the stopper 15, it has reached a defined starting position.

[0054] Figures 4 to 10 The problems in the prior art to be solved by the present invention will now be explained.

[0055] exist Figure 4 In FIG. 1 , the pressure value P measured by the pressure sensor 8 is plotted against the encoder value E output by the encoder 7 at the respective position for different positions of the control valve 1 . In addition, the diagram also shows the actual angle W, i.e. the actual position of the closure member 3 . Angle 0.0° corresponds to Figure 5 The minimum flow position shown in FIG. Angle W equal to 9.0° corresponds to the closing member 3 of the control valve 1 at Figure 6 The location shown in . Figure 4 The figure shows an ideal state in which the encoder outputs an encoder value of 0 when the closure member 3 is in the minimum flow position, that is, in other words, the maximum closed position. In this position, the pressure value P is maximum.

[0056] However, as explained at the beginning, Figures 4 to 6 This ideal state shown is usually not consistent with reality. Whether when the device is put into operation or after replacing the control valve 1 or the encoder 7 or the control drive 5 or its components, it may happen that the encoder 7 no longer outputs the encoder value 0 in the minimum flow position, but outputs any other encoder value. Figure 7 An example of this is shown in FIG. Here, the pressure value P measured by the pressure sensor 8 is also plotted against the encoder value E output by the encoder 7 at the corresponding position of the closing member 3. In addition, the angle W, i.e. the position, of the closing member 3 at the corresponding encoder value E is also shown here. Figure 4 As shown, this angle W is always measured relative to the minimum flow position.

[0057] Here you can choose any Figure 7 In the example shown, the maximum value Pmax of the pressure P measured by the pressure sensor 8 is not at encoder value 0, as is really desired, but at encoder value 4. The situation here is then that the minimum flow position at the maximum value Pmax of the measured pressure value P corresponds to encoder value 4, and not to encoder value 4 as would be expected according to Figure 4 Ideally this also corresponds to the encoder value 0. Figure 8 The closure member 3 is shown in Figure 7 The encoder value is 2. Fig. 9 The minimum flow position of the closure member 3 is shown, as it is in accordance with Figure 7 This is achieved in the example with an encoder value of 4. Fig.10 The closure member 3 is shown in Figure 7 The encoder value is 12 o'clock.

[0058] If you don't consider borrowing Figures 7 to 10The fact that the minimum flow position is not reached at encoder value 0, but at another encoder value, such as here in the present example at encoder value 4, leads to incorrect positions when the position of the closure member 3 is controlled by the control device 4. In the case of these incorrect positions, the closure member 3 is set at an angle W or a position that is different from what the control device 4 actually intended.

[0059] In order to be able to correct this possible error, a method for determining a correction value K of a control device 4 of a control valve 1 according to the present invention is proposed, wherein the control valve 1 controls a fluid flow flowing through a chamber 2, and a closing member 3 of the control valve 1 is arranged by the control device 4 at different positions relative to a flow opening 6 of the fluid flow through an adjusting drive device 5 of the control valve 1, wherein an encoder 7, in particular of the control valve 1, is provided, and each position of the closing member 3 corresponds to an encoder value E of the encoder 7, wherein at different positions of the closing member 3, a pressure value P, in particular representing the fluid in the chamber 2, is measured using a pressure sensor 8, wherein the position of the closing member 3 when the maximum value Pmax of the measured pressure value P is identified by the control device 4 as the minimum flow position of the closing member 3, and the correction value K is determined based on the encoder value E when the minimum flow position is identified.

[0060] With the help of Figures 11 to 14 A first variant of carrying out the method is shown. Fig.11 In FIG. 1 , the pressure value P measured by the pressure sensor 8 is again plotted for different positions of the closing element 3 against the encoder value E output by the encoder 7 in the corresponding position. Fig.11 The solid line in shows that the pressure P changes continuously with a change in the position of the closing member 3 from a small encoder value to a maximum value Pmax of the pressure value P in the range of encoder values ​​4 and that the pressure value P then decreases towards a larger encoder value. Fig.11 The crosses drawn in denoted measured values ​​in the case where the pressure P is not measured continuously but only at certain encoder values, as is the case in the present case, for example, when only integer encoder values ​​are output by the digital encoder 7 . Fig.12 Shown in Fig.11 The encoder value 0 is the position of the closed component. Fig.13 Shown in Fig.11 The encoder value 4 in the minimum flow position is the position of the closing member 3, Fig.14 As an example, it is shown Fig.11 The encoder value 8 in is the position of the closing member 3. It can be clearly seen that Fig.11In the implementation of the method according to the invention for determining the correction value K shown here by way of example, a maximum value Pmax of the pressure value P is detected at the encoder value 4. This encoder value 4 is then determined as the correction value K in this example of the method according to the invention.

[0061] If, instead of using an encoder 7 that outputs only integer encoder values ​​E, an encoder that outputs encoder values ​​E continuously is used, such as Fig.11 As shown by the solid curve in , it is possible to realize that the actual maximum value Pmax is not exactly at encoder value 4, but slightly deviates, as shown in Fig.11 This is also the case in . In order to be able to detect this situation or also to detect any gaps that may be present in the closing member 3 and to take them into account if necessary, the method for determining the correction value K according to the invention can also be performed twice, as already explained at the beginning. It can therefore be provided that the method is performed a first time and then a second time, wherein the position of the closing member 3 is passed through in the first direction 11 during the first time and in the second direction 12 that is opposite to the first direction 11 during the second time, the first correction value K1 is determined during the first time and the second correction value K2 is determined during the second time, and the correction value K is determined based on the first correction value K1 and the second correction value K2.

[0062] Fig.15 An example of this is shown in FIG. Here, the method is performed in the first direction 11, i.e. from a smaller encoder value to a larger encoder value E, and in the second direction 12 from a larger encoder value E to a smaller encoder value E. The symbol x is used in Fig.15 In the figure, the pressure value P determined when the method is carried out in the first direction 11 is represented. The pressure value P marked with a circle is determined when the method is carried out in the second direction 12. When the method is carried out for the first time, the correction value K1 is obtained. When the method is carried out for the second time, the correction value K2 is obtained from the corresponding position of the maximum value Pmax of the measured pressure value P. If this is compared with the solid line curve representing the continuous pressure measurement, it can be seen that both encoder values ​​E determined as correction values ​​K1 and K2 deviate slightly from the actual maximum value Pmax of the pressure value P. There are now various different feasible schemes for determining a common correction value K based on the first correction value K1 and the second correction value K2. For example, an averaging can be performed. It can also be decided to continue to use the smaller or larger of the two values ​​as the correction value K. If the control device 4 and the encoder 7 only work with integer encoder values ​​E, it can also be provided that the correction value K is rounded up or down to an integer. In any case, the residual error that may arise is reasonable. In Fig.15 In the example shown, the final determined correction value will also correspond to an encoder value of 4.

[0063] When carrying out the method according to the invention for determining the correction value K, as already explained at the outset, it is preferably provided in any case that during the entire execution of the method, the chamber 2 is permanently flowed through by the fluid, and the change in the position of the closure member 3 is the only change that affects the fluid flow during the method. It is also preferably provided that during the execution of the method, the fluid is pumped through the flow control valve 10, the chamber 2 and the flow opening 6 by means of the pump 9, wherein it is preferably provided that the control valve 1 is arranged between the pump 9 and the chamber 2.

[0064] In the embodiment variants of the method according to the invention for determining the correction value K described so far, as control valve 1, respectively Figure 2 and Figure 3 , or in other words, a butterfly valve. However, the method according to the invention for determining the correction value K is not limited to this type of valve. An exemplary selection of control valves 1 that can be used in the method according to the invention is very schematically and exemplarily shown in Figures 16 to 21 Shown in. Figures 16 to 18 A so-called swing valve is shown very schematically in FIG. In the case of this swing valve, the closing member 3 is also the valve plate. In the case of a swing valve, the valve plate is Figures 16 to 18 The adjusting drive 5, which is not explicitly shown in the figure, is pivoted about a pivot axis 13 which extends parallel to a normal 14 on the valve plate. The pivot axis 13 usually extends at or near the edge of the valve plate. Figures 16 to 18 Also shown in the figure is a stop 15. Such pendulum valves are known per se, so they do not need further explanation or more detailed illustration. In valves of this type, different positions of the closing member 3 are also different angular positions, which are then assigned to corresponding encoder values ​​E, respectively. Fig.16 The position of the closure member 3 on a first side of the minimum flow position is shown exemplarily. Fig.17 shows the minimum flow position, Fig.18 The method according to the invention for determining the correction value K can be used with such a control valve 1 using the above-explained and according to Figure 2 and Figure 3 It is also provided that the control device 4 identifies the position of the closing member 3 when the maximum value Pmax of the pressure value P is measured as the minimum flow position of the closing member 3, and determines the encoder value when the minimum flow position is identified as the correction value K.

[0065] exist Figures 19 to 21In the case of the control valve 1 schematically shown in FIG. 1 , the closing member 3 is likewise a valve plate. However, in a valve of this type, the valve plate is not pivotable, but is arranged to be movable by an adjusting drive 5. In the embodiment shown here, the closing member 3 is moved along a linear guide 18 by an adjusting drive 5, which is also not shown here. Such a sliding gate-like control valve 1 is known per se and likewise does not require further explanation. The method according to the invention for determining the correction value K can also be carried out with these control valves, wherein the different positions of the closing member 3 are then not different angular positions, but positions arranged along a preferably linear axis. Fig.19 It is again shown by way of example how the closure member 3 can be initially arranged on one side of the minimum flow position when carrying out the method according to the invention for determining the correction value K. Fig. 20 The minimum flow position is shown again in . Fig.21 The closing member 3 is shown in a position in which it has moved through the minimum flow position. However, even for this variant of the control valve 1, it is not necessary to have corresponding stops 15. If these stops 15 are present, the method according to the invention for determining the correction value K can provide that the method starts from an initial position of the closing member 3, in which the closing member 3 is located at the stops 15. However, as explained at the beginning, this is not necessarily the case. The stops 15 can also be omitted in all embodiments. For example, in the absence of the stops 15, it is also possible to move through all possible positions of the closing member 3 when carrying out the method according to the invention. However, it is usually sufficient to move through a certain range of positions in which the user of the method according to the invention envisages the minimum flow position.

[0066] After the correction value K has been determined according to the invention in the manner described, it can then be used for the operation or normal operation of the control valve 1. This is a method according to the invention for controlling the position of a closure member 3 of a control valve 1 by means of a control device 4, wherein the respective position of the closure member 3 to be controlled is determined by the control device 4 taking into account the correction value K determined according to the invention. This method is accomplished by means of Fig. 22 Here again, the pressure value P measured by the pressure sensor 8 is shown against the encoder value E. Also shown is the real angle W at which the closing member 3 is located in the first embodiment compared to the minimum flow position. In order to set the minimum flow position, in the method according to the invention, the control device 4 controls the closing member 3 not with an encoder value E equal to 0 but with an encoder value E equal to 4, wherein the encoder value E is precisely determined on the basis of the correction value K. Fig. 22 In the example shown, the correction value K is equal to 4. Fig.23 The minimum flow position of the closure member 3 is shown when the encoder value E is equal to 4. Fig.24The position of the closing member 3 is shown by way of example when the encoder value E is equal to 14. Fig. 22 In normal operation, which is shown by way of example, the closing member 3 preferably only reaches those positions when the corresponding encoder value E is greater than or equal to the correction value K. Alternatively, it is also conceivable that the corresponding encoder value E is less than or equal to the correction value K. Ultimately, this only means that the position of the closing member 3 is set only on one side of the minimum flow position, instead of using positions on both sides of the minimum flow position as is done when carrying out the method for determining the correction value.

[0067] List of Reference Numerals

[0068] 1 Control valve

[0069] 2 Chambers

[0070] 3 Closing components

[0071] 4 Control device

[0072] 5 Adjusting the drive

[0073] 6 Flow opening

[0074] 7 Encoder

[0075] 8. Pressure sensor

[0076] 9 Pumps

[0077] 10Flow control valve

[0078] 11 First Direction

[0079] 12 Second Direction

[0080] 13 Pivot Axis

[0081] 14 Normals

[0082] 15 stopper

[0083] 16 valve housing

[0084] 17 Fluid pipeline

[0085] 18 Linear guides

[0086] E Encoder value

[0087] P pressure value

[0088] Pmax Maximum value

[0089] K correction value

[0090] K1 first correction value

[0091] K2 Second correction value

[0092] W angle.

Claims

1. A method for determining a correction value (K) of a control device (4) of a control valve (1), wherein: The control valve (1) controls the flow of a fluid passing through a chamber (2), and the control device (4) arranges the closing member (3) of the control valve (1) at different positions relative to a flow opening (6) for the fluid flow through an adjusting drive device (5) of the control valve (1), wherein an encoder (7) is provided, in particular for the control valve (1), and each position of the closing member (3) corresponds to an encoder value (E) of the encoder (7), wherein pressure values ​​(P) representing the fluid in the chamber (2) are measured at different positions of the closing member (3) by means of a pressure sensor (8), wherein the position of the closing member (3) when the maximum value (Pmax) of the measured pressure value (P) is identified by the control device (4) as the minimum flow position of the closing member (3), and the correction value (K) is determined based on the encoder value (E) when the minimum flow position is identified.

2. The method according to claim 1, wherein: During the entire execution of the method, the chamber (2) is permanently flowed through by a fluid, and the change in the position of the closing member (3) is the only variable affecting the fluid flow that changes during the method.

3. The method according to claim 1 or 2, wherein: During the method, the fluid is pumped by means of a pump (9) through a flow control valve (10), the chamber (2) and the flow opening (6), wherein preferably provision is made for the control valve (1) to be arranged between the pump (9) and the chamber (2).

4. The method according to any one of claims 1 to 3, wherein: The method is performed for the first time and for the second time, wherein the position of the closing member (3) is passed in a first direction (11) during the first time, and the position of the closing member (3) is passed in a second direction (12) opposite to the first direction (11) during the second time, and a first correction value (K1) is determined during the first time, and a second correction value (K2) is determined during the second time, and the correction value (K) is determined based on the first correction value (K1) and the second correction value (K2).

5. The method according to any one of claims 1 to 4, wherein: The closing member (3) is a valve plate which can be pivoted by the adjustment drive (5) about a pivot axis (13) extending along the valve plate, wherein the valve plate protrudes beyond the pivot axis (13) on mutually opposite sides of the pivot axis (13).

6. The method according to any one of claims 1 to 4, wherein: The closing component (3) is a valve plate which can be pivoted by the adjusting drive (5) about a pivot axis (13) extending parallel to a normal (14) on the valve plate.

7. The method according to any one of claims 1 to 4, wherein: The closing element (3) is preferably mounted so that it can be displaced linearly by means of the adjustment drive (5).

8. The method according to any one of claims 1 to 7, wherein: The control valve (1) has a starting position which is predetermined by a stop (15) or in another way, and when the method is carried out, the closure member (3) is arranged in different positions relative to a flow opening (6) for the fluid flow starting from the starting position of the closure member (3).

9. A method for controlling the position of a closing member (3) of a control valve (1) by means of a control device (4), wherein: Taking into account the correction value (X) determined by the method according to any one of claims 1 to 8, the control device (4) determines the respective position of the closing element (3) to be controlled.

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