TW202102962A - Flow rate control device, flow rate measuring method, and computer readable storage medium - Google Patents

Abstract

In order to provide a flow rate control device capable of guaranteeing the correctness of a valve flow rate without increasing the flow path resistance between a flow rate control valve and the supply target, the disclosures provides a flow rate control valve V2 provided in a main flow path ML; a second pressure sensor P2 provided on the upstream side of the flow rate control valve V2; a flow rate controller 2 which controls the flow rate control valve V2 based on at least a second pressure measured by the second pressure sensor P2 and a set flow rate; a first branch flow path DL1 which branches at the downstream side of the flow rate control valve V2 in the main path flow ML and is connected to the supply target of the fluid; a second branch flow path DL2 which branches at the downstream side of the flow rate control valve V2 in the main flow path ML; a third pressure sensor P3 provided on the second branch flow path DL2; and a valve flow rate calculator 3 which calculates the flow rate of the fluid passing through the flow rate control valve V2 based on at least the second pressure and a third pressure measured by the third pressure sensor P3.

Description

Flow control device, flow measurement method, and computer readable storage medium

The present invention relates to a flow control device such as a mass flow controller.

For example, in a semiconductor manufacturing process, it is necessary to accurately supply process gas, etc., to a supply target such as a chamber at a predetermined set flow rate. For example, as described in Patent Document 1, among the mass flow controllers used for this purpose, there are the following ones, which include a pressure control valve provided on the upstream side, and a flow control valve provided on the downstream side and including an opening sensor Valves and various sensors that measure the temperature and pressure of the fluid in the volume between the two valves.

The mass flow controller uses a pressure control valve located on the upstream side to control the pressure of the gas in the volume at a constant level, and then uses a flow control valve located on the downstream side to control the flow rate of the gas flowing out of the volume. Take control.

Specifically, the mass flow controller memorizes a map indicating the relationship between the temperature and pressure of the fluid in the volume, the flow rate of the fluid passing through the flow control valve, and the opening degree of the flow control valve. Then, the mass flow controller outputs the corresponding opening degree as the set opening degree based on the set flow rate and the measured temperature and pressure reference map. In addition, the flow control valve is controlled so that the measured opening degree measured by the opening degree sensor becomes the set opening degree.

In addition, in the above-mentioned mapping, the relationship between the various parameters changes due to changes over the years or the use environment, and it may not be possible to output an accurate flow rate from the mass flow controller. Therefore, the mapping must be appropriately corrected based on a certain reference flow rate.

In Patent Document 1, for the correction of the mapping, the following correction operation is performed, for example, during the period during which no process is performed in the chamber. First, the flow control valve on the downstream side is completely closed, and a gas of a predetermined pressure is stored in the volume between the pressure control valve and the flow control valve. Then, the pressure control valve on the upstream side was completely closed, and the flow control valve was opened, and the pressure and temperature changes in the volume from that point in time were measured. The flow rate of the gas flowing out of the volume through the flow control valve is calculated by substituting the differential value of the pressure representing the time change of the pressure and the temperature into the flow calculation formula derived from the gas state equation. When the measured flow rate calculated as above is compared with the flow rate under the corresponding condition memorized in the map, if there is a difference of a predetermined value or more, the flow rate memorized in the map is updated to the measured flow rate.

However, even if the map is updated by this correction method, the various valve operations as described above cannot be performed during the actual flow control period. Therefore, the flow rate of the gas flowing from the flow control valve, that is, the valve flow rate cannot be monitored. That is, in the actual manufacturing process, it is impossible to guarantee whether a truly accurate flow rate is supplied to the chamber.

On the other hand, if a flow sensor is installed between the downstream side of the flow control valve of the mass flow controller and the chamber to measure the valve flow rate to ensure the accuracy of the valve flow rate, the flow path resistance is used for The fluid resistance members etc. installed for flow measurement are greatly enlarged. Therefore, for example, the response speed during transient response is greatly reduced, and the required specifications may not be met. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-064893

[The problem to be solved by the invention]

The present invention is made in view of the above-mentioned problems, and its object is to provide a flow control device capable of ensuring the accuracy of the valve flow rate without causing an increase in the flow path resistance between the flow control valve and the supply target. [Means to solve the problem]

That is, the flow control device of the present invention includes: a flow control valve provided in the main flow path; a second pressure sensor provided on the upstream side of the flow control valve; and a flow controller based at least on the second pressure sensor The second pressure and the set flow rate measured by the detector are used to control the flow control valve; the first branch flow path is branched on the downstream side of the flow control valve in the main flow path, and is connected to the supply target of the fluid Connection; a second branch flow path, which branches on the downstream side of the flow control valve in the main flow path; a third pressure sensor, which is provided on the second branch flow path; and a valve flow calculation unit, based on at least The second pressure and the third pressure measured by the third pressure sensor are used to calculate the flow rate of the fluid passing through the flow control valve.

In addition, the flow control method of the present invention is used in a flow control device. The flow control device includes: a flow control valve arranged in the main flow path; a second pressure sensor arranged on the upstream side of the flow control valve; and a flow control valve. The controller controls the flow control valve based on at least the second pressure measured by the second pressure sensor and the set flow rate. In the flow measurement method, a first branch flow path is provided, and a first branch flow path is provided in the flow rate measurement method. The main flow path is branched on the downstream side of the flow control valve and connected to the supply target of the fluid; the second branch flow path is branched on the downstream side of the flow control valve in the main flow path; and the third pressure sense A sensor is arranged on the second branch flow path, and calculates the amount of fluid passing through the flow control valve based on at least the second pressure and the third pressure measured by the third pressure sensor flow.

If it is the above, the third pressure sensor for calculating the valve flow rate is provided on the second branch flow path, and the second branch flow path is connected to the downstream side of the flow control valve. The first branch flow path to which the supply target is connected is branched separately, and therefore it is possible to prevent an increase in flow path resistance between the flow control valve and the supply target. In addition, the valve flow rate calculation unit can always calculate the valve flow rate of the fluid passing through the flow control valve based on the second pressure and the third pressure, and therefore can always monitor the valve flow rate.

In order to be able to estimate the flow rate of the fluid passing through the flow control valve, that is, the valve flow rate, and realize flow feedback control, the following may be listed, which further includes: a fluid resistance member disposed on the upstream side of the second pressure sensor; A first pressure sensor is provided on the upstream side of the fluid resistance member; and a resistance flow calculation unit that calculates based on the first pressure measured by the first pressure sensor and the second pressure For the flow rate of the fluid flowing in the fluid resistance member, the flow rate controller includes: a mapping memory unit that at least represents the resistance flow rate calculated by the resistance flow rate calculation unit, the second pressure, and the flow rate A map of the relationship between the flow rates of the fluids of the flow control valve; a map reference unit, based on the measured resistance flow rate and the second pressure, refers to the map, and passes through the corresponding flow control The flow rate of the fluid of the valve is output as an estimated valve flow rate; and an opening degree control unit that controls the flow rate control valve so that the estimated valve flow rate becomes the set flow rate. In addition, if it is as described above, whether the result of controlling the flow control valve based on the estimated valve flow rate is operating accurately can be determined by referring to the actually measured valve flow rate calculated by the flow rate calculation unit. confirm.

For example, in order to further improve the response speed of the transient response in the flow control, or in the flow control, the influence caused by the fluctuation of the supply pressure to the chamber is not easily displayed, as long as it is the following, which further includes: a pressure control valve , Provided on the upstream side of the first pressure sensor; and a pressure control unit that controls the pressure control valve so that the first pressure becomes a set pressure.

As a control method for realizing flow control without using a fluid resistance member in the flow control device, an opening sensor for measuring the opening of the flow control valve is further included. The following can be listed, wherein the flow controller includes: a mapping memory portion that stores at least the relationship between the second pressure, the opening degree of the flow control valve, and the flow rate of the fluid passing through the flow control valve A map of the relationship; a map reference unit that refers to the map based on the measured second pressure and the set flow rate, and outputs the corresponding opening of the flow control valve as the set opening; and an opening control unit , Controlling the flow control valve so that the measured opening degree measured by the opening degree sensor becomes the set opening degree.

In order to implement a constant pressure control in the control method and improve the response speed of the flow control, the following may be cited, which further includes: a pressure control valve provided on the upstream side of the second pressure sensor; and a pressure control unit , Controlling the pressure control valve so that the second pressure becomes the set pressure.

In order to output the valve flow rate output from the flow control valve at an accurate value even if there is a change over the years, the following may be sufficient, which further includes a corrector based on the valve flow rate calculation unit calculated Measure the valve flow rate and update the mapping.

In order to directly use the map when occasional errors occur, and only update the map when systematic errors occur, the following may be sufficient, among which the estimated valve flow rate and the measured valve flow rate If the difference between is greater than or equal to a predetermined value, the corrector updates the map.

As a specific configuration for calculating the valve flow rate passing through the flow control valve based on the second pressure and the third pressure, the following can be cited. That is, the valve flow calculation unit is based on the flow of the flow control valve. The differential pressure between the second pressure and the third pressure is used to calculate the actual valve flow rate.

For example, as an example of a configuration for speeding up the transient response control of the flow rate of the fluid passing through the flow control valve, it may be as long as it includes: a fluid resistance member provided on the second pressure sensor The upstream side of the sensor; the first pressure sensor is provided on the upstream side of the fluid resistance member; the resistance flow calculation unit is based on the first pressure measured by the first pressure sensor and the first pressure sensor Two pressures to calculate the flow rate of the fluid flowing in the fluid resistance member; and a pressure control valve, which is provided on the upstream side of the first pressure sensor, and the flow controller includes: a valve flow estimating unit based on The flow rate through the flow control valve is estimated from the resistance flow rate calculated by the resistance flow rate calculation unit and the time change amount of the first pressure measured by the first pressure sensor; and an opening degree control unit , Controlling the flow rate control valve so that the estimated valve flow rate estimated by the valve flow rate estimating unit becomes the set flow rate. If it is as described above, the information of the pressure between the pressure control valve and the fluid resistance member can be used to calculate the flow rate of the fluid passing through the flow control valve to improve the control performance of the transient response.

If it is the following flow control device, it includes: a flow control valve arranged in the main flow path; a second pressure sensor arranged on the upstream side of the flow control valve; a pressure control valve arranged on the second pressure sensor And one or more temperature sensors arranged in the volume formed between the pressure control valve and the flow control valve, and a temperature sensor is arranged on the outside of the volume, Compared with the case where the temperature of the fluid is measured indirectly, it is possible to accurately measure the temperature of the fluid actually flowing. As a result, the accurate fluid temperature can be used to calculate, for example, an accurate flow rate.

In order to stabilize the temperature of the fluid in the volume, the temperature of the fluid flowing in the volume can be measured more accurately, as long as it is as long as it further includes a mesh member filled in the volume.

In order to achieve more accurate flow control based on the accurately measured fluid temperature than before, it only needs to be the following, which further includes: a flow controller, based at least on the second pressure sensor measured by the second pressure sensor The second pressure, the temperature measured by the temperature sensor, and the set flow rate are used to control the flow control valve.

As long as it is configured as follows, it further includes a valve flow calculation unit that calculates the flow rate of the fluid passing through the flow control valve based on at least the second pressure and the measured temperature measured by the temperature sensor. The accurately measured temperature is used to accurately calculate the flow rate of the fluid passing through the flow control valve.

In order to be able to more accurately calculate the flow rate of the fluid passing through the flow control valve in the flow control, without increasing the flow path resistance between the flow control valve and the fluid supply target, the following may be sufficient: It further includes: a first branch flow path, which branches on the downstream side of the flow control valve in the main flow path, and is connected to the supply target of the fluid; a second branch flow path, which is in the main flow path at the flow rate The downstream side branch of the control valve; and a third pressure sensor provided on the second branch flow path, and the valve flow calculation unit is configured to be based on at least the second pressure by the third pressure sensor The measured third pressure and the measured temperature are used to calculate the flow rate of the fluid passing through the flow control valve.

In order to enjoy the same effect as the flow control device of the present invention by updating the program used in the existing flow control device, it is sufficient to use the following flow control device program, that is, for the flow control device, the flow control The device includes: a flow control valve arranged in the main flow path; a second pressure sensor arranged on the upstream side of the flow control valve; a first branch flow path in the main flow path downstream of the flow control valve Side branch, and connected to the supply target of the fluid; a second branch flow path, which branches on the downstream side of the flow control valve in the main flow path; and a third pressure sensor, which is provided in the second branch flow On the road, in the program for the flow control device, the computer functions as a flow controller and a valve flow calculation unit, and the flow controller is based on at least the second pressure and the set flow rate measured by the second pressure sensor To control the flow control valve, and the valve flow calculation unit calculates the flow through the flow control valve based on at least the second pressure and the third pressure measured by the third pressure sensor The flow rate of the fluid.

Furthermore, the flow control device program can be transmitted electronically, or recorded on compact discs (Compact Disc, CD), digital versatile discs (Digital Versatile Disc, DVD), hard disk drives (Hard Disk Drive, HDD), Program recording media such as flash memory. [Effects of the invention]

In this way, in the case of the flow control device of the present invention, the third pressure sensor is provided on the second branch flow path formed on the downstream side of the flow control valve and not connected to the supply target of the fluid. Therefore, the flow rate of the fluid passing through the flow control valve can be actually measured based on the output of the third pressure sensor without increasing the flow path resistance on the downstream side of the flow control valve. As a result, it is actually possible to monitor the valve flow rate and perform flow control.

The flow control device 100 according to the first embodiment of the present invention will be described with reference to Fig. 1. The flow control device 100 of the first embodiment is used, for example, in a semiconductor manufacturing process to supply a gas as a fluid to the chamber CN at a set flow rate.

That is, as shown in FIG. 1, the flow control device 100 includes a sensor provided in a flow path, a fluid device including a valve, and a control mechanism COM that controls the fluid device.

For the main flow path ML, a supply pressure sensor P0, a pressure control valve V1, a first pressure sensor P1 as a first pressure sensor, a fluid resistance member R, and a second pressure sensor are arranged in order from the upstream side. The second pressure sensor P2 of the sensor, the flow control valve V2. In addition, the downstream side of the flow control valve V2 of the main flow path ML is branched into two flow paths, and a first branch flow path DL1 connected to the chamber CN as the supply target of the fluid is provided, and the downstream side which is not connected to the chamber CN is provided. The second branch flow path DL2 whose ends are closed. Furthermore, the second branch flow path DL2 is provided with a third pressure sensor P3 as a third pressure sensor that measures the pressure on the downstream side of the flow control valve V2. Here, the fluid resistance member R is, for example, a laminar flow element, and generates a differential pressure corresponding to the flow rate of the flowing gas before and after it.

The supply pressure sensor P0 is used to monitor the pressure of the gas supplied from the upstream side. Furthermore, regarding the supply pressure sensor P0, it may be omitted when the supply pressure is ensured to be stable, etc.

The first pressure sensor P1 measures the first pressure, which is the pressure of the gas charged in the volume between the pressure control valve V1 on the upstream side and the fluid resistance member R in the flow path, that is, the upstream volume .

The second pressure sensor P2 measures the second pressure, which is the pressure of the gas charged in the volume between the fluid resistance member R and the downstream flow control valve V2 in the flow path, that is, the downstream volume .

In this way, the first pressure sensor P1 and the second pressure sensor P2 respectively measure the pressure of the two volumes formed by the pressure control valve V1, the fluid resistance member R, and the flow control valve V2. In addition, if other expressions are made, the first pressure sensor P1 and the second pressure sensor P2 measure the pressure in the respective volumes arranged before and after the fluid resistance member R.

The pressure control valve V1 and the flow control valve V2 are the same type of valve in the first embodiment, for example, a piezoelectric valve in which a valve body is driven relative to a valve seat by a piezoelectric element. The pressure control valve V1 and the flow control valve V2 each change the opening degree in accordance with the voltage input as the operation amount. Here, at least the flow control valve V2 includes an opening sensor V21, which can measure the current opening. As the opening degree sensor V21, a displacement sensor etc. which output based on the operation|movement of a valve body, a plunger connected to a valve body, an actuator, etc. are mentioned.

Next, the control mechanism COM will be described in detail.

The control mechanism COM includes, for example, a central processing unit (Central Processing Unit, CPU), memory, analog to digital (Analog to Digital, A/D) converters, digital to analog (D/A) converters, input and output The so-called computer such as components, etc., by executing the program for the flow control device stored in the memory to make various devices work together, at least the resistance flow calculation unit 1, the flow controller 2, the valve flow calculation unit 3, the corrector 4, and the pressure The function of the control unit 5.

The resistance flow calculation unit 1 constitutes a so-called differential pressure type flow sensor FM together with the first pressure sensor P1, the fluid resistance member R, and the second pressure sensor P2. That is, the resistance flow calculation unit 1 takes the first pressure measured by the first pressure sensor P1 and the second pressure measured by the second pressure sensor P2 as inputs, and calculates the value of the fluid flowing in the fluid resistance member R The flow rate is the resistance flow rate and is output. Here, the calculation formula of the flow rate used in the resistance flow rate calculation unit 1 can use an existing one. The resistance flow rate calculated by the resistance flow rate calculation unit 1 changes continuously, but a predetermined time delay occurs with respect to the actual flow rate through the flow rate control valve V2 achieved by the control of the flow rate control valve V2.

The flow controller 2 controls the flow control valve V2 based on at least the second pressure measured by the second pressure sensor P2 and the set flow rate set by the user so that the flow rate of the fluid passing through the flow control valve V2 is equal to The valve flow rate becomes the set flow rate. In the first embodiment, the flow controller 2 estimates the valve flow rate based on the resistance flow rate calculated by the resistance flow calculation unit 1 and the second pressure measured by the second pressure sensor, and performs control on the flow control valve V2. Flow rate feedback control so that the valve flow rate becomes the set flow rate. Here, the estimation of the valve flow rate is performed based on the resistance flow rate and the second pressure with reference to the map.

Specifically, as shown in FIG. 2, the flow controller 2 includes a map storage unit 21, a map reference unit 22, and an opening degree control unit 23.

The map storage unit 21 stores a map representing at least the relationship between the resistance flow rate, the second pressure, and the valve flow rate. Such a mapping is, for example, in a state where the combination of each resistance flow rate and the second pressure is realized, a flow sensor is actually arranged on the downstream side of the flow control valve V2 for actual measurement, and the relationship database of each parameter is formed. . For the mapping, it may be in the form of a table or an expression that expresses the relationship between the parameters.

The map reference unit 22 refers to the map stored in the map storage unit 21 based on the measured resistance flow rate and the second pressure, and outputs the corresponding valve flow rate to the opening degree control unit 23 as the estimated valve flow rate. The valve flow rate estimated as described above is configured to have a smaller delay with respect to the actual valve flow rate than the resistance flow rate.

The opening degree control unit 23 controls the flow control valve V2 so that the estimated valve flow rate becomes the set flow rate. In the first embodiment, the opening degree control unit 23 performs feedback control on the voltage applied to the flow control valve V2 so that the deviation between the estimated valve flow rate and the set flow rate is reduced.

The valve flow calculation unit 3 shown in FIG. 1 calculates the flow rate of the fluid passing through the flow control valve V2 based on at least the second pressure and the third pressure measured by the third pressure sensor. Specifically, the valve flow calculation unit 3 calculates the actual valve flow based on the conductance determined by the opening degree of the flow control valve V2 and the differential pressure between the second pressure and the third pressure. Here, the valve flow calculation unit 3 memorizes a table showing the relationship between the opening degree and the conductance, and uses the conductance corresponding to the opening measured by the opening sensor V21 to output the actually measured valve flow. In this way, the valve flow calculation unit 3 calculates the flow rate of the fluid passing through the flow control valve V2 based on the actual measurement value. Therefore, unlike the estimated valve flow rate, the valve flow rate is a value actually measured in real time during flow control. In addition, in this embodiment, the actually measured valve flow rate is used to update the map.

As shown in FIGS. 1 and 2, the corrector 4 updates the map in the flow controller 2 based on the actual valve flow rate calculated by the valve flow calculation unit 3. Specifically, when the difference between the estimated valve flow rate and the actual valve flow rate used in the control of the flow control valve V2 is greater than a predetermined value, the valve corresponding to the second pressure and the resistance flow rate at that point in the map The flow rate is updated to the actual valve flow rate.

The pressure control unit 5 controls the pressure control valve V1 based on the set pressure set by the user and the first pressure measured by the first pressure sensor P1. Specifically, the pressure control unit 5 performs pressure feedback control on the voltage applied to the pressure control valve V1 so that the deviation between the set pressure and the first pressure is reduced.

According to the flow control device 100 of the first embodiment configured as described above, the flow control valve V2 can perform flow feedback control so that the set flow rate can be achieved, and the flow control valve V2 can be used to pass through the flow control valve based on the second pressure and the third pressure. V2 fluid flow rate is monitored.

In addition, the third pressure sensor P3 provided on the downstream side of the flow control valve V2 is provided on the second branch flow path DL2 that is not connected to the chamber CN as the supply target, so it will not be used to control the valve flow rate. The equipment installed in actual measurement increases the flow path resistance between the flow control valve V2 and the chamber CN. Therefore, the flow control device 100 of the first embodiment can ensure the accuracy of the valve flow of the fluid passing through the flow control valve V2 and keep the response speed high.

A modification example of the first embodiment will be described.

Regarding the map, in order to consider the influence of the temperature of the fluid, it can also be set to represent the relationship between the resistance flow rate, the second pressure, the temperature, and the valve flow rate.

In this case, for example, the temperature of the fluid resistance member R can be measured by a temperature sensor such as a thermistor, and the map reference unit 22 may be configured to refer to the map based on the measured temperature, second pressure, and resistance flow rate. Just output the valve flow.

In addition, regarding the conductance used in the valve flow calculation unit 3, a different value may be used according to the temperature measured by the temperature sensor.

Next, the second embodiment of the present invention will be described.

As shown in FIGS. 3 and 4, in the flow control device 100 of the second embodiment, the configuration of the flow controller 2 is different from that of the first embodiment.

Specifically, the configuration for calculating the estimated valve flow rate in the flow controller 2 is not a reference map, but a configuration based on the time change amount of the first pressure. Therefore, the second pressure is input to the flow controller 2 of the first embodiment, while, as shown in FIG. 3, the first pressure is input to the flow controller 2 of the second embodiment.

Specifically, as shown in FIG. 4, the flow controller 2 includes a valve flow estimation unit 24 instead of the map memory unit 21 and the map reference unit 22, which is based on the value calculated by the resistance flow calculation unit 1 The resistance flow rate and the time change amount of the first pressure measured by the first pressure sensor P1 are used to estimate the flow rate passing through the flow control valve V2.

The valve flow estimation unit 24 includes: a time change calculation unit 25 that calculates, for example, a time differential value of the first pressure as the time change of the first pressure, and outputs a value obtained by multiplying the differential value by a predetermined coefficient; and output The section 26 calculates the estimated valve flow rate based on the time change amount and the resistance flow rate from the time change amount calculation section 25. Furthermore, the time change calculation unit 25 is not limited to differentiating the first pressure, and may also perform a difference calculation for each sampling time of the first pressure sensor P1.

In addition, in the second embodiment, when the difference between the estimated valve flow rate and the actual valve flow rate is greater than or equal to a predetermined value, the corrector 4 corrects the coefficient used in the time change amount calculation unit 25 based on the difference.

With the flow control device 100 of the second embodiment configured as described above, the resistance flow rate can be corrected based on the time differential value of the first pressure to calculate the estimated valve flow rate. In addition, the resistance flow rate can be output in consideration of the change in the pressure on the upstream side, so that the transient change of the valve flow rate can be corrected.

Next, a flow control device 100 according to a third embodiment of the present invention will be described with reference to FIGS. 5 and 6.

Unlike the flow control device 100 shown in the first and second embodiments, the flow control device 100 of the third embodiment does not have a fluid resistance member R between the pressure control valve V1 and the flow control valve V2, and the pressure control valve A large volume VL is formed between V1 and the flow control valve V2. In addition, regarding the pressure sensor, the first pressure sensor is omitted, and only the second pressure sensor P2 is provided. That is, the function for measuring the flow rate is omitted in this volume, and the control of the pressure control valve V1 is also performed based on the output of the second pressure sensor P2.

In addition, since the resistance flow rate is not measured, as shown in FIG. 6, the configuration of the flow controller 2 is also different from the first embodiment and the second embodiment. That is, the flow controller 2 calculates the set opening corresponding to the realized valve flow based on the second pressure and the set flow measured by the second pressure sensor P2, and controls the flow control valve V2 so that The deviation between the calculated setting opening degree and the measurement opening degree measured by the opening degree sensor V21 becomes smaller.

Specifically, in the flow controller 2 of the third embodiment, the map shows at least the relationship between the second pressure, the opening degree of the flow control valve V2, and the flow rate of the fluid passing through the flow control valve V2. Then, the map reference unit 22 outputs the corresponding set opening degree with reference to the map based on the measured second pressure and the measured opening degree, and the set flow rate set by the user.

In addition, the opening control unit 23 controls the voltage applied to the flow control valve V2 so that the measured opening output from the opening sensor V21 provided in the flow control valve V2 becomes the set opening output from the map reference unit 22 degree.

As shown in FIG. 5, the valve flow calculation unit 3 inputs the second pressure, which is the upstream pressure of the flow control valve V2, the third pressure which is the downstream pressure, and the measured opening degree, and calculates the actual valve flow based on these values. More specifically, the valve flow calculation unit 3 calculates the actual valve flow rate for each control cycle based on the differential pressure between the second pressure and the third pressure and the conductance corresponding to the measured opening of the flow control valve V2.

As shown in FIGS. 5 and 6, the corrector 4 updates the map every time the valve flow calculation unit 3 calculates the actual valve flow rate. Specifically, in the set of the second pressure, the opening degree, and the flow rate referred to in order to output the set opening degree, the flow rate is updated to the actual measured flow rate.

With the flow control device 100 of the third embodiment configured in this way, even if the flow rate is not measured based on the differential pressure using the fluid resistance member as in the first and second embodiments, it can be estimated that the flow through the flow control valve The valve flow rate of V2 is used for flow control.

In addition, the valve flow rate passing through the flow control valve V2 is actually measured based on the pressure before and after the flow control valve V2, and the map is sequentially updated. Therefore, even if the flow control valve V2 is controlled as described above, it can be based on substantially constant measurement. The flow rate of the valve is used to control the valve flow rate.

Therefore, unlike before, the flow rate of the chamber CN can be ensured even in the state where the fluid is supplied to the chamber CN. In addition, since it is possible to avoid disposing devices as flow path resistance in the main flow path ML and the second branch flow path DL2 as much as possible, it is possible to improve, for example, transient response characteristics and ensure flow accuracy.

A modification example of the third embodiment will be described.

Regarding the third embodiment, the flow control valve V2 may not be controlled by referring to the map, but the opening degree of the flow control valve V2 may be directly controlled based on the measured flow rate. Specifically, the flow controller 2 may not include the map storage unit 21 and the map reference unit 22, and the actual valve flow rate calculated by the valve flow rate calculation unit 3 may be fed back to the opening degree control unit 23. That is, the opening degree control unit 23 may also control the voltage applied to the flow control valve V2 so that it is based on the second pressure measured by the second pressure sensor P2 and the voltage measured by the third pressure sensor P3. The deviation between the actual valve flow rate calculated by the measured third pressure and the set flow rate becomes smaller.

In addition, the flow control device 100 may further include a temperature sensor that measures the temperature of the fluid flowing in the volume VL between the pressure control valve V1 and the flow control valve V2, based on the consideration The temperature mapping is used for flow control. That is, a map may be used to indicate the relationship between the second pressure, opening degree, temperature, and flow rate, and the map reference unit 22 may output the set opening degree based on the measured second pressure, opening degree, and temperature.

Next, a fourth embodiment of the present invention will be described with reference to Figs. 7 and 8. In addition, the same reference numerals are given to members corresponding to the members described in the third embodiment.

Similar to the flow control device 100 shown in the third embodiment, the flow control device 100 of the fourth embodiment does not have a fluid resistance member R between the pressure control valve V1 and the flow control valve V2, and the pressure control valve V1 and the flow control A large volume VL is formed between the valves V2.

More specifically, between the pressure control valve V1 and the flow control valve V2, there are provided a volume VL as a cavity formed inside, an introduction path for introducing or discharging gas to the volume VL, and a block with a discharge path formed inside. BL. In addition, a pressure control valve V1 is provided to the gas inlet of the block BL, and a flow control valve V2 is provided to the gas outlet of the block BL. As shown in FIG. 8, in a volume VL formed inside the block BL, a mesh member M filled in the entire volume VL and a temperature sensor for measuring the temperature of the gas in the volume VL are provided TS.

Regarding the mesh member M, for example, a member having a mesh number such that the temperature of the gas existing in the volume VL is almost uniform without substantially obstructing the passage of gas is selected. By filling the mesh member M in the volume VL, it is possible to improve the stability of the measured temperature at the time of temperature measurement for map update, which will be described later, and obtain an accurate value.

The temperature sensor TS is arranged in contact with a part of the mesh member M in the volume VL. As shown in FIG. 8, the temperature sensor TS is in contact with the inner wall surface of the block BL in the volume VL, or is in contact with the mesh member M at a position close to the inner wall surface, and the wiring is easily drawn out of the block BL. Since the temperature sensor TS is installed at a position in direct contact with the gas, for example, one having corrosion resistance can be appropriately selected according to the type of gas flowing. In this embodiment, two temperature sensors TS are provided in the volume VL, and the average value of the measured temperatures of these temperature sensors TS is used as the gas temperature. Furthermore, the number of temperature sensors TS can be appropriately selected, and it can be one or three or more. In addition, the temperature sensor TS may be one that is installed in the volume VL and directly measures the temperature of the fluid.

In addition, in the flow controller 2 of the fourth embodiment, the map shows at least the relationship between the second pressure, the opening degree of the flow control valve V2, the temperature of the gas, and the flow rate of the gas passing through the flow control valve V2. Then, the map reference unit 22 outputs the corresponding setting opening degree with reference to the map based on the measured second pressure, the measured opening degree, the measured temperature measured by the temperature sensor TS, and the set flow rate set by the user.

In addition, the opening control unit 23 controls the voltage applied to the flow control valve V2 so that the measured opening output from the opening sensor V21 provided in the flow control valve V2 becomes the set opening output from the map reference unit 22 degree.

The valve flow calculation unit 3 calculates the actual valve based on the second pressure and the measured temperature acquired during the correction control for updating the map without performing flow control by the opening control unit 23. flow. If the ROF method is briefly explained, it is as follows. First, the space between the pressure control valve V1 and the flow control valve V2 is filled with gas of a predetermined pressure. Then, the flow control valve V2 is opened at a predetermined opening degree to reduce the pressure of the gas in the space. Based on the second pressure measured at the time of the pressure drop, the measured temperature, the volume value of the space filled with gas, and the equation of the gas state equation time-differentiated, the flow rate through the flow control valve V2 can be calculated. In the fourth embodiment, the mesh member M is filled in the volume VL to make the temperature of the gas uniform, and therefore it is also possible to accurately measure the temperature of the gas when the pressure drops. As a result, the valve flow calculation unit 3 can accurately calculate the actually measured valve flow.

The corrector 4 updates the map every time the valve flow calculation unit 3 calculates the actual valve flow rate. Specifically, the flow rate corresponding to the set of the second pressure, opening degree, and temperature used when the valve flow calculation unit 3 calculates the actual valve flow rate is updated to the actual measurement valve flow rate.

In the flow control device 100 of the fourth embodiment configured as described above, the mesh member M is filled in the volume VL between the pressure control valve V1 and the flow control valve V2, and the temperature sensor TS is installed in the volume VL Therefore, for example, the gas temperature required for calculating the actual valve flow rate based on the gas state equation can be accurately obtained. As a result, the actual valve flow rate calculated during the update of the flow rate map can be made more accurate, and the accuracy of the final flow control can be further improved.

A modification example of the fourth embodiment will be described. In the fourth embodiment, the mesh member M is filled in the volume VL, but the mesh member M may be omitted, and only the temperature sensor TS is provided in the volume VL. In addition, as in the third embodiment, in the fourth embodiment, the main flow path ML is also branched into a first branch flow path DL1 connected to the supply destination of the fluid on the downstream side of the flow control valve V2, and a first branch flow path DL1 that is not connected to the fluid. The second branch flow path DL2 connected to the supply target is provided with a third pressure sensor P3 as a third pressure sensor in the second branch flow path DL2. In the case where the branch flow paths DL1, the branch flow paths DL2, and the third pressure sensor P3 are provided in this way, the valve flow calculation unit 3 may also be configured to be based on at least the second pressure sensor P2 measured by the second pressure sensor P2. The second pressure, the third pressure measured by the third pressure sensor P3, and the measured temperature measured by the temperature sensor TS, calculate the flow rate of the fluid passing through the flow control valve V2.

Other embodiments will be described.

The method of calculating the actual valve flow rate based on the second pressure and the third pressure is not limited to the calculation using conductance as shown in each embodiment. For example, it can also be set to pre-measure a map showing the relationship between the second pressure, the third pressure and the valve flow rate, and make it a database, and refer to the map under the measured second pressure and the third pressure to correspond The flow rate is output as the valve flow rate. In addition, it is also possible to omit the corrector and provide only the valve flow calculation unit, and perform feedback control on the flow control valve based on the actually measured valve flow calculated by the valve flow calculation unit.

In addition, as long as it does not violate the gist of the present invention, a part of each embodiment may be combined with each other, or may be modified. [Industrial availability]

In this way, according to the present invention, it is possible to provide a flow control device capable of ensuring the accuracy of the valve flow rate without causing an increase in the flow path resistance between the flow control valve and the supply target.

1: Resistance flow calculation unit 2: flow controller 3: Valve flow calculation section 4: corrector 5: Pressure Control Department 21: Mapping Memory Department 22: Mapping reference part 23: Opening degree control section 24: Valve flow estimation section 25: Time change calculation department 26: output section 100: Flow control device BL: block CN: Chamber COM: control mechanism DL1: The first branch flow path (branch flow path) DL2: The second branch flow path (branch flow path) FM: Flow sensor M: Mesh component ML: Mainstream Road P0: Supply pressure sensor P1: The first pressure sensor P2: The second pressure sensor P3: Third pressure sensor R: fluid resistance member TS: Temperature sensor V1: Pressure control valve V2: Flow control valve V21: Opening sensor VL: Volume

Fig. 1 is a schematic diagram showing the configuration of a flow control device according to a first embodiment of the present invention. Fig. 2 is a schematic diagram showing the configuration of a flow controller of the flow control device according to the first embodiment of the present invention. Fig. 3 is a schematic diagram showing the configuration of a flow control device according to a second embodiment of the present invention. Fig. 4 is a schematic diagram showing the configuration of a flow controller of a flow control device according to a second embodiment of the present invention. Fig. 5 is a schematic diagram showing the configuration of a flow control device according to a third embodiment of the present invention. Fig. 6 is a schematic diagram showing the configuration of a flow controller of a flow control device according to a third embodiment of the present invention. Fig. 7 is a schematic diagram showing the configuration of a flow control device according to a fourth embodiment of the present invention. Fig. 8 is a schematic cross-sectional view showing the details of the internal structure of a flow control device according to a fourth embodiment of the present invention.

1: Resistance flow calculation unit

2: flow controller

3: Valve flow calculation section

4: corrector

5: Pressure Control Department

100: Flow control device

CN: Chamber

COM: control mechanism

DL1: The first branch flow path (branch flow path)

DL2: Second branch flow path (branch flow path)

FM: Flow sensor

ML: Mainstream Road

P0: Supply pressure sensor

P1: The first pressure sensor

P2: The second pressure sensor

P3: Third pressure sensor

R: fluid resistance member

V1: Pressure control valve

V2: Flow control valve

V21: Opening sensor

Claims (16)

A flow control device, which is characterized by comprising: Flow control valve, set in the main flow path; The second pressure sensor is arranged on the upstream side of the flow control valve; A flow controller, which controls the flow control valve at least based on the second pressure and the set flow measured by the second pressure sensor; A first branch flow path, which branches on the downstream side of the flow control valve in the main flow path, and is connected to the supply target of the fluid; A second branch flow path that branches on the downstream side of the flow control valve in the main flow path; The third pressure sensor is arranged on the second branch flow path; and The valve flow rate calculation unit calculates the flow rate of the fluid passing through the flow control valve based on at least the second pressure and the third pressure measured by the third pressure sensor. The flow control device according to claim 1, further comprising: The fluid resistance member is arranged on the upstream side of the second pressure sensor; The first pressure sensor is arranged on the upstream side of the fluid resistance member; and The resistance flow rate calculation unit calculates the flow rate of the fluid flowing in the fluid resistance member based on the first pressure and the second pressure measured by the first pressure sensor, and The flow controller includes: A mapping memory unit that stores a map representing at least the relationship between the resistance flow rate calculated by the resistance flow rate calculation unit, the second pressure, and the flow rate of the fluid passing through the flow control valve; A map reference unit, which refers to the map based on the measured resistance flow rate and the second pressure, and outputs the flow rate of the fluid passing through the corresponding flow control valve as the estimated valve flow rate; and The opening degree control unit controls the flow control valve so that the estimated valve flow rate becomes the set flow rate. The flow control device described in claim 2 further includes: The pressure control valve is arranged on the upstream side of the first pressure sensor; and The pressure control unit controls the pressure control valve so that the first pressure becomes a set pressure. The flow control device according to claim 1, further comprising an opening sensor for measuring the opening of the flow control valve, The flow controller includes: A mapping memory unit, which stores a map representing at least the relationship between the second pressure, the opening degree of the flow control valve, and the flow rate of the fluid passing through the flow control valve; A map reference unit, which refers to the map based on the measured second pressure and the set flow rate, and outputs the corresponding opening degree of the flow control valve as the set opening degree; and The opening degree control unit controls the flow control valve so that the measured opening degree measured by the opening degree sensor becomes the set opening degree. The flow control device according to claim 4 further includes: The pressure control valve is arranged on the upstream side of the second pressure sensor; and The pressure control unit controls the pressure control valve so that the second pressure becomes a set pressure. The flow control device according to claim 1, further comprising: a corrector that updates the map based on the actually measured valve flow rate calculated by the valve flow rate calculation unit. The flow control device according to claim 6, wherein the corrector updates the map when the difference between the estimated valve flow rate and the actual measured valve flow rate is a predetermined value or more. The flow control device according to any one of claims 1 to 7, wherein the valve flow calculation unit is based on the conductance of the flow control valve and the differential pressure between the second pressure and the third pressure , To calculate the measured valve flow. The flow control device according to claim 1, including: The fluid resistance member is arranged on the upstream side of the second pressure sensor; The first pressure sensor is arranged on the upstream side of the fluid resistance member; A resistance flow rate calculation unit that calculates the flow rate of the fluid flowing in the fluid resistance member based on the first pressure and the second pressure measured by the first pressure sensor; and The pressure control valve is arranged on the upstream side of the first pressure sensor, The flow controller includes: The valve flow rate estimating unit estimates the flow rate passing through the flow control valve based on the resistance flow rate calculated by the resistance flow rate calculation unit and the time change amount of the first pressure measured by the first pressure sensor Flow; and The opening degree control unit controls the flow control valve so that the estimated valve flow rate estimated by the valve flow estimation unit becomes the set flow rate. A flow control device, which is characterized by comprising: Flow control valve, set in the main flow path; The second pressure sensor is arranged on the upstream side of the flow control valve; The pressure control valve is arranged on the upstream side of the second pressure sensor; and One or more temperature sensors are arranged in the volume formed between the pressure control valve and the flow control valve. The flow control device according to claim 10, further comprising a grid member filled in the volume. The flow control device according to claim 10, further comprising: a flow controller based at least on the second pressure measured by the second pressure sensor, the temperature measured by the temperature sensor, and settings The flow rate is used to control the flow rate control valve. The flow control device according to any one of claim 10 to claim 12, further comprising: a valve flow calculation unit that calculates based on at least the second pressure and the measured temperature measured by the temperature sensor The flow rate of fluid passing through the flow control valve. The flow control device according to claim 13, further comprising: A first branch flow path, which branches on the downstream side of the flow control valve in the main flow path, and is connected to the supply target of the fluid; A second branch flow path that branches on the downstream side of the flow control valve in the main flow path; and The third pressure sensor is arranged on the second branch flow path, The valve flow calculation unit is configured to calculate the amount of fluid passing through the flow control valve based on at least the second pressure, the third pressure measured by the third pressure sensor, and the measured temperature. flow. A flow measurement method for a flow control device, the flow control device comprising: a flow control valve arranged in the main flow path; a second pressure sensor arranged on the upstream side of the flow control valve; and a flow controller, The flow control valve is controlled based on at least the second pressure and the set flow rate measured by the second pressure sensor, and the flow rate measurement method is characterized by: A first branch flow path is provided, which branches on the downstream side of the flow control valve in the main flow path, and is connected to the supply target of the fluid; a second branch flow path is located in the main flow path at the flow control valve And a third pressure sensor arranged on the second branch flow path, and The flow rate of the fluid passing through the flow control valve is calculated based on at least the second pressure and the third pressure measured by the third pressure sensor. A computer-readable storage medium stores a program for a flow control device, the program for the flow control device is used for a flow control device, and the flow control device includes: a flow control valve arranged in a main flow path; a second pressure sensing The detector is arranged on the upstream side of the flow control valve; a first branch flow path that branches in the main flow path on the downstream side of the flow control valve and is connected to the supply target of the fluid; the second branch flow path , Branch in the main flow path on the downstream side of the flow control valve; and a third pressure sensor arranged on the second branch flow path, the flow control device program is characterized by: A computer is made to function as a flow controller and a valve flow calculation unit, the flow controller controlling the flow control valve based on at least the second pressure and the set flow measured by the second pressure sensor, The valve flow calculation unit calculates the flow rate of the fluid passing through the flow control valve based on at least the second pressure and the third pressure measured by the third pressure sensor.

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