Flow rate measurement mechanism and fluid control apparatus

Abstract

To enable highly accurate flow rate measurements while reducing costs.SOLUTION: A flow rate measurement mechanism includes: a fluid resistance element 41 provided on a flow path 2R through which a fluid flows and having a resistance flow path 41a formed therein; a fluid receiving portion 4x provided on the flow path 2R and configured to be hit by the fluid flowing from upstream of the fluid resistance element 41, so as to cause the fluid to flow to a side; flexible members 42a, 42b configured to support the fluid resistance element 41 and to deform in accordance with a flow rate of the fluid; a displacement sensor 43 configured to measure a displacement of the flexible components 42a, 42b; and a flow rate calculation unit 44 configured to calculate a flow rate of the fluid, based on the displacement measured by the displacement sensor 43. The fluid that is caused to flow to the side by the fluid receiving portion 4x flows along the resistance flow path 41a of the fluid resistance element 41.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flow rate measurement mechanism and a fluid control device.

Background Art

[0002] Conventionally, as a flow rate sensor used in a fluid control device (so-called mass flow controller), there is a pressure type one. This pressure type flow rate sensor measures the upstream pressure of a fluid resistance element in a flow path using an upstream pressure sensor, measures the downstream pressure of the fluid resistance element using a downstream pressure sensor, and measures the flow rate based on the upstream pressure and the downstream pressure measured by these pressure sensors.

[0003] However, two sensors, an upstream pressure sensor and a downstream pressure sensor, are required to measure the flow rate. To measure a high-precision flow rate, a high-precision pressure sensor is required, resulting in a high cost.

[0004] On the other hand, as shown in Patent Document 2, a method of calculating the flow rate by measuring the displacement of a diaphragm provided in a linear flow path without using a pressure sensor has been considered. Specifically, an opening through which fluid can pass is formed in the diaphragm.

[0005] However, in the above configuration, the opening is formed along the direction of the linear flow path, and since the portion other than the opening is configured to be deformed by receiving pressure from the fluid, the area receiving pressure from the fluid is restricted by the opening. As a result, the amount of deformation of the diaphragm based on the change in the flow rate becomes small, and it becomes difficult to accurately obtain the flow rate from the amount of deformation of the diaphragm.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to enable highly accurate flow rate measurement while reducing costs.

Means for Solving the Problems

[0008] That is, the flow rate measurement mechanism according to the present invention is provided in a flow path through which a fluid flows, and includes a fluid resistance element in which a resistance flow path is formed, a fluid receiving portion provided in the flow path, against which the fluid flowing from the upstream side of the fluid resistance element hits and causes the fluid to flow sideways, a flexible member that supports the fluid resistance element and deforms according to the flow rate of the fluid, a displacement sensor that measures the displacement of the flexible member, and a flow rate calculation unit that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor, and is configured such that the fluid flowing sideways by the fluid receiving portion flows through the resistance flow path of the fluid resistance element.

[0009] With such a flow rate measurement mechanism, it is not necessary to use two pressure sensors, an upstream pressure sensor and a downstream pressure sensor, as in the prior art, so that the cost of the flow rate measurement mechanism can be reduced. Further, since the fluid flowing from the upstream side of the fluid resistance element hits the fluid receiving portion and then the fluid flowing sideways flows through the resistance flow path of the fluid resistance element, the area for receiving the pressure of the fluid flowing through the flow path can be increased, and the amount of deformation of the diaphragm based on the change in the flow rate can be increased. As a result, when the displacement of the flexible member is measured and the flow rate of the fluid is calculated based on the displacement, highly accurate flow rate measurement becomes possible.

[0010] As a specific embodiment of the fluid resistance element, it is conceivable that the fluid resistance element is composed of a laminate, and the resistance flow path is formed in a direction intersecting the lamination direction. In this case, it is desirable that the flexible member supports the upstream portion of the fluid resistance element.

[0011] As a specific embodiment of the fluid resistance element, it is conceivable that a fluid introduction portion is formed at the center of the fluid resistance element when viewed from the lamination direction, and the resistance flow path extends from the fluid introduction portion toward the outer peripheral portion. In this configuration, it is desirable that the fluid receiving portion is provided facing the fluid introduction portion on the downstream side of the central portion of the fluid resistance element. With this configuration, the area for receiving the pressure of the fluid flowing through the flow path can be increased, and the amount of deformation of the diaphragm based on the change in the flow rate can be increased.

[0012] The flexible member has an upstream flexible member and a downstream flexible member that support the fluid resistance element therebetween, and no through hole is formed in the downstream flexible member, and it is desirable that the fluid flows out from between the upstream flexible member and the downstream flexible member. Further, a through hole for introducing the fluid into the fluid resistance element is formed in the upstream flexible member, and it is desirable that the fluid that has passed through the fluid resistance element flows out from between the upstream flexible member and the downstream flexible member.

[0013] Further, when the downstream flexible member in the pair of flexible members is flat, the amount of displacement of the downstream flexible member can be increased. In that configuration, it is desirable that the displacement sensor measures the displacement of the downstream flexible member in the pair of flexible members.

[0014] When a fluid resistance element is sandwiched between a pair of flexible members, a space is formed outside the fluid resistance element between the upstream flexible member and the downstream flexible member. In order to effectively utilize this space to miniaturize the flow rate measuring mechanism, it is desirable that the displacement sensor be provided outside the fluid resistance element between the upstream flexible member and the downstream flexible member.

[0015] It is desirable that the flow rate measuring mechanism of the present invention further includes an annular spacer member provided so as to surround the periphery of the fluid resistance element between the upstream flexible member and the downstream flexible member. With this configuration, it becomes easy to fix a pair of flexible members sandwiching the fluid resistance element to the flow path block. That is, a pair of flexible members may be sandwiched by the flow path block via the spacer member. In this configuration, in order to allow the fluid that has passed through the fluid resistance element to flow out to the outside of the pair of flexible members, it is desirable that the spacer member be formed with an outflow path through which the fluid that has passed through the fluid resistance element passes.

[0016] It is desirable that the flow rate measuring mechanism of the present invention further includes a magnetic force adjustment mechanism that adjusts the displacement of the flexible member or the fluid resistance element by magnetic force, and the flow rate calculation unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor and the magnetic force by the magnetic force adjustment mechanism. With this configuration, since the displacement of the flexible member or the fluid resistance element according to the flow rate of the fluid can be adjusted by magnetic force, the flow rate measurement range or the flow rate measurement sensitivity can be dynamically adjusted. That is, by combining the deformation by the flexible member and the magnetic force, the flow rate calculated by the flow rate calculation unit can be varied. For example, when expanding the flow rate measurement range, it is conceivable to increase the magnetic force by the magnetic force adjustment mechanism to make it difficult for the flexible member to deform according to the flow rate. Also, when increasing the flow rate measurement sensitivity, it is conceivable to decrease or set the magnetic force to zero by the magnetic force adjustment mechanism to make it easy for the flexible member to deform according to the flow rate.

[0017] Further, the flow rate measurement mechanism according to the present invention is provided in a flow path through which a fluid flows, and includes a fluid resistance element in which a resistance flow path is formed, a flexible member that supports the fluid resistance element and deforms according to the flow rate of the fluid, a displacement sensor that measures the displacement of the flexible member or the fluid resistance element, a magnetic force adjustment mechanism that adjusts the displacement of the flexible member or the fluid resistance element by magnetic force, and a flow rate calculation unit that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor.

[0018] With this flow rate measurement mechanism, since the displacement of the flexible member or the fluid resistance element according to the flow rate of the fluid can be adjusted by magnetic force, the flow rate measurement range or the flow rate measurement sensitivity can be dynamically adjusted. That is, by combining the deformation by the flexible member and the magnetic force, the flow rate calculated by the flow rate calculation unit can be varied. For example, when expanding the flow rate measurement range, it is conceivable to increase the magnetic force by the magnetic force adjustment mechanism to make it difficult for the flexible member to deform according to the flow rate. Also, when increasing the flow rate measurement sensitivity, it is conceivable to decrease or set the magnetic force to zero by the magnetic force adjustment mechanism to make it easy for the flexible member to deform according to the flow rate.

[0019] As a specific embodiment, it is desirable that a magnet on which the magnetic force acts is provided on the flexible member or the fluid resistance element, and the magnetic force adjustment mechanism has an electromagnetic coil that generates the magnetic force. With this configuration, by controlling the current flowing through the electromagnetic coil, the displacement of the flexible member or the fluid resistance element can be adjusted by magnetic force. Also, by passing a high current pulse through the electromagnetic coil, the fluid resistance element can be quickly returned to its original position.

[0020] As a specific embodiment, it is desirable that the flow rate calculation unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor and the magnetic force by the magnetic force adjustment mechanism.

[0021] The flow rate measurement mechanism according to the present invention preferably further includes a pressure sensor provided upstream of the fluid resistance element in the flow path and a temperature sensor for measuring the temperature of the fluid flowing through the flow path. In this configuration, it is desirable that the flow rate calculation unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor, the pressure measured by the pressure sensor, and the temperature measured by the temperature sensor. Specifically, it is desirable that the flow rate calculation unit corrects the density of the fluid using the pressure measured by the pressure sensor and calculates the flow rate of the fluid.

[0022] Further, the fluid control device according to the present invention is characterized by including the above-described flow rate measurement mechanism and a fluid control valve provided upstream or downstream of the flow rate measurement mechanism.

Advantages of the Invention

[0023] Thus, according to the present invention, it is possible to achieve highly accurate flow rate measurement while reducing costs.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0025] Hereinafter, an embodiment of the fluid control device according to the present invention will be described with reference to the drawings. Note that, for the sake of clarity, all the figures shown below are schematically drawn with appropriate omissions or exaggerations. The same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0026] <Configuration of the fluid control device> The fluid control device 100 of the present embodiment is used, for example, in a semiconductor manufacturing process, and is provided in one or a plurality of gas supply lines to control the flow rate of the process gas flowing through each gas supply line.

[0027] Specifically, as shown in FIG. 1, the fluid control device 100 includes a flow path block 2 in which an internal flow path 2R is formed, and a fluid control device 3 mounted on the flow path block 2.

[0028] The flow path block 2 is provided with an introduction port P1 for introducing fluid into the internal flow path 2R and a discharge port P2 for discharging fluid from the internal flow path 2R. An upstream pipe (not shown) is connected to the introduction port P1, and a downstream pipe (not shown) is connected to the discharge port P2.

[0029] The fluid control device 3 controls the fluid in the internal flow path 2R, and includes a flow rate measurement mechanism 4 for measuring the flow rate of the fluid flowing through the internal flow path 2R, a fluid control valve 5 provided on the upstream side or the downstream side (downstream side in FIG. 1) of the flow rate measurement mechanism 4, and a valve control unit 6 that feedback-controls the valve opening degree of the fluid control valve 5 based on the deviation between the measured flow rate and the set flow rate of the flow rate measurement mechanism 4.

[0030] The fluid control valve 5 controls the flow rate, for example, by moving the valve body forward and backward with respect to the valve seat by an actuator such as a piezo actuator.

[0031] Further, the valve control unit 6 is a so-called computer including, for example, a CPU, a memory, an A / D·D / A converter, and input / output means. By executing a fluid control program stored in the memory and causing various devices to cooperate, the valve control unit 6 exhibits its function as the valve control unit 6.

[0032] <Specific Configuration of the Flow Rate Measurement Mechanism 4> Next, the specific configuration of the flow rate measurement mechanism 4 of the present embodiment will be described with reference to FIGS. 2 and 3.

[0033] Specifically, as shown in FIGS. 2 and 3, the flow rate measurement mechanism 4 includes a fluid resistance element 41, a fluid receiving portion 4x, flexible members 42a and 42b that support the fluid resistance element 41 therebetween and deform according to the flow rate of the fluid, a displacement sensor 43 that measures the displacement of the flexible members 42a and 42b, and a flow rate calculation unit 44 that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor 43.

[0034] In the flow rate measurement mechanism 4 of the present embodiment, the fluid resistance element 41, the fluid receiving portion 4x, the flexible members 42a and 42b, and the displacement sensor 43 are provided in a measurement block 40 that forms a measurement space 40S. The measurement space 40S formed in the measurement block 40 communicates with the internal flow path 2R. Here, the measurement block 40 is formed with an introduction path 40a for introducing the fluid flowing through the internal flow path 2R into the measurement space 40S and a lead-out path 40b for leading the fluid from the measurement space 40S to the internal flow path 2R. Further, the introduction path 40a and the lead-out path 40b are in a positional relationship of intersecting (for example, orthogonal) with each other. Note that the introduction path 40a is formed in a first block element 401 of the measurement block 40 described later. The lead-out path 40b is formed between the first block element 401 and a second block element 402 of the measurement block 40 described later.

[0035] The fluid resistance element 41 is provided in the measurement block 40, and a resistance flow path 41a communicating with the measurement space 40S is formed therein. This fluid resistance element 41 is provided so as to face the inlet of the introduction path 40a. The fluid resistance element 41 of the present embodiment is composed of a laminate in which a plurality of thin plates are laminated, and a plurality of resistance flow paths 41a are formed inside in a direction intersecting (for example, orthogonal) to the lamination direction.

[0036] Specifically, the fluid resistance element 41 has a substantially rotating body shape, and a fluid introduction portion 411 in which the start end of the resistance flow path 41a opens at the center portion thereof as viewed from the lamination direction is formed, and the resistance flow path 41a extends from the fluid introduction portion 411 toward the outer peripheral portion. That is, in the fluid resistance element 41 of the present embodiment, the end of the resistance flow path 41a opens on the outer peripheral surface thereof, and the fluid flows out from the outer peripheral surface. That is, the fluid resistance element 41 changes the flowing direction of the fluid introduced from the introduction path 40a (here, the introduction direction of the introduction path 40a) to a direction intersecting therewith (here, the derivation direction of the derivation path 40b) and causes it to flow out.

[0037] The flexible members 42a and 42b have an upstream flexible member 42a and a downstream flexible member 42b that support the fluid resistance element 41 with the measurement block 40 interposed therebetween. The pair of flexible members 42a and 42b are provided so as to face the inlet of the introduction path 40a. Further, the pair of flexible members 42a and 42b are deformed according to the flow rate of the fluid flowing in from the introduction path 40a of the measurement block 40. The pair of flexible members 42a and 42b are formed of thin metal plates (diaphragms).

[0038] A pair of flexible members 42a and 42b sandwich and support the fluid resistance element 41 in the stacking direction. Among the pair of flexible members 42a and 42b, the upstream flexible member 42a supports the upstream portion of the fluid resistance element 41, and a through hole 421 for allowing fluid to flow into the fluid resistance element 41 is formed therein. This through hole 421 is formed corresponding to the fluid introduction portion 411 of the fluid resistance element 41 and communicates with the fluid introduction portion 411. Further, among the pair of flexible members 42a and 42b, the downstream flexible member 42b supports the downstream portion of the fluid resistance element 41, and no through hole is formed at the position corresponding to the fluid resistance element 41.

[0039] That is, the downstream flexible member 42b has a configuration having a fluid receiving portion 4x. This fluid receiving portion 4x deflects the fluid hitting it from the upstream side of the fluid resistance element 41 to the side. Specifically, the fluid receiving portion 4x is provided facing the fluid introduction portion 411 on the downstream side of the central portion of the fluid resistance element 41. Since the fluid introduction portion 411 in the fluid resistance element 41 of the present embodiment penetrates the central portion, the flexible member 42b closes the end of this through portion, and the portion closing the through portion becomes the fluid receiving portion 4x. Then, the fluid flowing laterally by the fluid receiving portion 4x flows through the resistance flow path 41a of the fluid resistance element 41.

[0040] Here, an annular spacer member 45 is provided between the pair of flexible members 42a and 42b so as to surround the periphery of the fluid resistance element 41. This spacer member 45 keeps the gap between the pair of flexible members 42a and 42b sandwiching the fluid resistance element 41 constant. In the present embodiment, the measurement block 40 has a first block element 401 and a second block element 402, and these block elements 401 and 402 sandwich the pair of flexible members 42a and 42b. Here, a pair of flexible members 42a and 42b are sandwiched using fixing screws 403. Therefore, the spacer member 45 keeps the gap between the pair of flexible members 42a and 42b constant in a state where the pair of flexible members 42a and 42b are sandwiched by the block elements 401 and 402.

[0041] Further, the spacer member 45 is provided at a predetermined distance from the outer circumferential surface of the fluid resistance element 41. The spacer member of the present embodiment has an annular shape and is arranged concentrically with the fluid resistance element 41. Here, in the pair of flexible members 42a and 42b, a deformed portion 422 is mainly formed between the spacer member 45 and the fluid resistance element 51. And an outflow passage 45a through which the fluid that has passed through the fluid resistance element 41 passes is formed in the spacer member 45.

[0042] In such a configuration, the fluid that has flowed into the measurement space 40S from the introduction passage 40a of the measurement block 40 flows into the fluid introduction portion 411 of the fluid resistance element 41 through the through hole 421 of the upstream flexible member 42a. The fluid that has flowed into the fluid introduction portion 411 hits the fluid receiving portion 4x, and the flowing direction is changed and the fluid goes toward the side (here, the radially outer side) of the fluid resistance element 41. Then, it flows through the resistance passage 41a of the fluid resistance element 41 and flows out between the pair of flexible members 42a and 42b from the outer circumferential surface of the fluid resistance element 41. Here, the fluid that has flowed in from the introduction passage 40a hits the pair of flexible members 42a and 42b and the fluid resistance element 41, and the pair of flexible members 42a and 42b are bent and displaced to the side opposite to the introduction passage 40a. And the fluid that has passed through the fluid resistance element 41 passes through the outflow passage 45a of the spacer member 45 and flows out to the outside from between the pair of flexible members 42a and 42b. Then, it flows through the outlet passage 40b of the measurement block 40 and flows out to the internal flow path 2R.

[0043] The displacement sensor 43 measures the displacement of the pair of flexible members 42a and 42b. In the present embodiment, it measures the displacement of the downstream flexible member 42b. Specifically, the displacement sensor 43 is provided on the side opposite to the measurement space 40S (introduction passage 40a) with respect to the downstream flexible member 42b. That is, the displacement sensor 43 of the present embodiment is provided outside the measurement space 40S. As the displacement sensor 43, a capacitance type sensor, an oil-filled pressure sensor, a position sensor, a magnetic sensor, an eddy current sensor, or the like can be used.

[0044] The flow rate calculation unit 44 calculates the flow rate of the fluid flowing through the internal flow path 2R (fluid resistance element 41) based on the displacement measured by the displacement sensor 43. Specifically, the flow rate calculation unit 44 calculates the flow rate from the displacement measured by the displacement sensor 43 using the relational data indicating the relationship between the displacement measured by the displacement sensor 43 and the flow rate.

[0045] In the present embodiment, a pressure sensor 46 for measuring the upstream pressure of the fluid resistance element 41 and a temperature sensor 47 for measuring the temperature of the fluid flowing through the fluid resistance element 41 are provided. The flow rate calculation unit 44 corrects the fluid flow rate based on the upstream pressure measured by the pressure sensor 46 and the temperature measured by the temperature sensor 47. That is, the flow rate calculation unit 44 can perform density correction of the fluid by using the upstream pressure and temperature. Note that the pressure sensor 46 and the temperature sensor 47 are mounted on the flow path block 2.

[0046] <Effects of the present embodiment> As described above, according to the fluid control device 100 in the present embodiment, it is not necessary to use two pressure sensors, an upstream pressure sensor and a downstream pressure sensor, as in the prior art, so the cost of the flow rate measurement mechanism 4 can be reduced. Further, since the fluid flowing from the upstream side of the fluid resistance element 41 hits the fluid receiving portion 4x, and then the fluid flowing laterally flows through the resistance flow path 41a of the fluid resistance element 41, the area for receiving the pressure of the fluid flowing through the flow path can be increased, and the amount of deformation of the diaphragm based on the change in the flow rate can be increased. As a result, when the displacements of the flexible members 42a and 42b are measured and the flow rate of the fluid is calculated based on the displacements, highly accurate flow rate measurement becomes possible.

[0047] <Other embodiments> For example, in the above embodiment, the pressure sensor 46 and the temperature sensor 47 are provided on the upstream side of the fluid resistance element 41, the gas density is obtained from the upstream pressure obtained by the pressure sensor 46 and the temperature obtained by the temperature sensor 47, and the flow rate is corrected by the gas density. However, it is not necessary to correct the flow rate by the gas density. It is not necessary to use it for flow rate correction.

[0048] Also, as shown in FIG. 4, the displacement sensor 43 may be provided outside the fluid resistance element 41 between the pair of flexible members 42a and 42b. In this case, the displacement sensor 43 may be provided between the fluid resistance element 41 and the spacer member 45 between the pair of flexible members 42a and 42b. With this configuration, the flow rate measurement mechanism 4 can be miniaturized.

[0049] Further, in the above embodiment, the measurement block 40 is configured to be provided with the fluid resistance element 41, the pair of flexible members 42a and 42b, and the displacement sensor 43. However, it may be configured to be provided in the flow path block 2 without using the measurement block 40.

[0050] Furthermore, in the above embodiment, the spacer member 45 is provided between the pair of flexible members 42a and 42b. However, a spacer portion may be integrally provided on at least one of the pair of flexible members 42a and 42b.

[0051] In addition, in the above embodiment, the fluid flows out between the pair of flexible members 42a and 42b. However, for example, a configuration may be adopted in which an outlet is formed outside the fluid resistance element 41 in the downstream flexible member 42b.

[0052] The above embodiment has a configuration having a pair of flexible members 42a and 42b, but may have a configuration having only the upstream flexible member 42a.

[0053] Also, in the above embodiment, the fluid receiving portion 4x is constituted by the downstream flexible member 42b. However, the fluid receiving portion 4x may be constituted without using the downstream flexible member 42b by closing the opening on the downstream side of the fluid introduction portion 411 of the fluid resistance element 41 with a thin plate or the like.

[0054] Moreover, the fluid resistance element of the above embodiment may be a ceramic restrictor in which a large number of through holes are formed in the ceramic. In this case, it is conceivable to support the ceramic restrictor by sandwiching it from both sides along the through holes with a pair of flexible members.

[0055] Further, as shown in FIG. 5, the flow rate measuring mechanism 4 may have the following configuration. In FIG. 5, the same reference numerals are given to the members and parts identical or corresponding to those in the above embodiment.

[0056] The flow rate measuring mechanism 4 shown in FIG. 5 includes a fluid resistance element 41, a fluid receiving portion 4x, a flexible member 42 that supports the fluid resistance element 41 and deforms according to the flow rate of the fluid, a displacement sensor 43 that measures the displacement of the fluid resistance element 41 or the flexible member 42, a magnetic force adjusting mechanism 48 that adjusts the displacement of the fluid resistance element 41 or the flexible member 42 by magnetic force, and a flow rate calculation unit 44 that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor 43. Here, the fluid resistance element 41 is the same as that in the above embodiment, but it may be other things such as a ceramic restrictor or an orifice in which a large number of through holes are formed in the ceramic. Further, the fluid receiving portion 4x is configured by closing the opening on the downstream side of the fluid introduction portion 411 of the fluid resistance element 41 with a thin plate or the like.

[0057] The flexible member 42 is provided so as to close the flow path 40R in, for example, a cylindrical measurement block 40 that forms a flow path 40R communicating with the internal flow path 2R. This flexible member 42 supports the fluid introduction portion 411 side of the fluid resistance element 41, and a through hole 421 for allowing the fluid to flow into the fluid resistance element 41 is formed. This through hole 421 is formed corresponding to the fluid introduction portion 411 of the fluid resistance element 41 and communicates with the fluid introduction portion 411. Note that the flexible member 42 may support the fluid resistance element 41 by being connected to the peripheral edge portion on the fluid introduction portion 411 side of the fluid resistance element 41.

[0058] The displacement sensor 43 measures the displacement of the fluid resistance element 41 or the flexible member 42. In this embodiment, it measures the displacement of the fluid resistance element 41. Specifically, the displacement sensor 43 is provided on the downstream side of the flow path 40R with respect to the fluid resistance element 41. As the displacement sensor 43, a capacitance type sensor, an oil-filled pressure sensor, a position sensor, a magnetic sensor, an eddy current sensor, or the like can be used.

[0059] The magnetic force adjustment mechanism 48 adjusts the displacement of the fluid resistance element 41 or the flexible member 42 by magnetic force. This magnetic force adjustment mechanism 48 has a magnet 48a provided on the fluid resistance element 41 or the flexible member 42, and an electromagnetic coil 48b that generates a magnetic force acting on the magnet 48a. In this embodiment, the magnet 48a is provided on the fluid resistance element 41. Specifically, the magnet 48a is provided on the outer peripheral portion of the fluid resistance element 41. This magnet 48a has, for example, an annular shape along the outer appearance shape of the fluid resistance element 41. Note that a part of the fluid resistance element 41 may be constituted by a magnet.

[0060] Further, the electromagnetic coil 48b is provided so as to be located on the side of the fluid resistance element 41 (magnet 48a) in the measurement block 40. This electromagnetic coil 48b has an annular shape provided so as to surround the fluid resistance element 41 (magnet 48a) in the measurement block 40. Note that the magnetic force generated by the electromagnetic coil 48b is adjusted by controlling the current flowing through the electromagnetic coil 48b by the current control unit 48c.

[0061] Then, when a current is passed through the electromagnetic coil 48b by the current control unit 48c, as shown in FIGS. 5 and 6, a magnetic force acts on the magnet 48a. Here, a magnetic attraction force acts between the electromagnetic coil 48b and the magnet 48a. As shown in FIG. 6, when the flexible member 42 receives pressure from the fluid and deforms downstream, a force opposite to the pressure received from the fluid acts on the fluid resistance element 41 and the flexible member 42 by the magnetic force acting on the magnet 48a. Note that in a state where the flexible member 42 is not deformed, even if a magnetic force acts on the magnet 48a, the above-described opposite force is not configured to act.

[0062] For example, when the flow rate control unit 48c expands the flow rate measurement range (measurement range), it increases the current flowing through the electromagnetic coil 48b, increases the magnetic force acting on the magnet 48a, and makes it difficult for the flexible member 42 to deform according to the flow rate. Also, when the flow rate control unit 48b increases the flow rate measurement sensitivity, it decreases or sets to zero the current flowing through the electromagnetic coil 48b, decreases or sets to zero the magnetic force acting on the magnet 48a, and makes it easy for the flexible member 42 to deform according to the flow rate.

[0063] In addition, the current control unit 48c can switch to a plurality of set currents preset corresponding to each of the plurality of flow rate measurement ranges (measurement ranges) or flow rate measurement sensitivities. Furthermore, the current control unit 48c can also adjust the current flowing through the electromagnetic coil 48b based on the displacement amount measured by the displacement sensor 43. For example, the current control unit 48c can increase the current flowing through the electromagnetic coil 48b as the displacement amount measured by the displacement sensor 43 increases.

[0064] The flow rate calculation unit 44 calculates the flow rate flowing through the internal flow path 2R (fluid resistance element 41) based on the displacement measured by the displacement sensor 43 and the magnetic force by the magnetic force adjustment mechanism 48. Specifically, the flow rate calculation unit 44 calculates the flow rate flowing through the internal flow path 2R (fluid resistance element 41) based on the displacement measured by the displacement sensor 43 and the current flowing through the electromagnetic coil 48a. Here, the flow rate calculation unit 44 calculates the flow rate from the displacement measured by the displacement sensor 43 and the current flowing through the electromagnetic coil 48a using relationship data indicating the relationship between the displacement measured by the displacement sensor 43, the current flowing through the electromagnetic coil 48a, and the flow rate.

[0065] In addition, the flow rate calculation unit 44 corrects the flow rate of the fluid based on the upstream pressure measured by the pressure sensor 46 and the temperature measured by the temperature sensor 47 in the same manner as in the above embodiment. That is, the flow rate calculation unit 44 can perform density correction of the fluid by using the upstream pressure and temperature.

[0066] In the case of the flow rate measurement mechanism 4 shown in FIG. 5, since the displacement of the fluid resistance element 41 or the flexible member 42 generated according to the flow rate of the fluid can be adjusted by magnetic force, the flow rate measurement range or the flow rate measurement sensitivity can be dynamically adjusted.

[0067] In addition, various modifications and combinations of the embodiments may be made as long as they do not depart from the spirit of the present invention.

Explanation of Signs

[0068] 100 ··· Fluid control device 2R ··· Flow path 41a ··· Resistance flow path 4 ··· Flow rate measurement mechanism 41 ··· Fluid resistance element 4x ··· Fluid receiving part 411 ··· Fluid introduction part 42a ··· Upstream flexible member 421 ··· Through hole 42b ··· Downstream flexible member 43 ··· Displacement sensor 44 ··· Flow rate calculation part 45 ··· Spacer member 45a ··· Outflow path 46 ··· Pressure sensor 5 ··· Fluid control valve 42 ··· Flexible member 48 ··· Magnetic force adjustment mechanism 48a ··· Magnet 48b ··· Electromagnetic coil

Claims

1. A fluid resistance element provided in a flow path through which a fluid flows and having a resistance flow path formed therein, a fluid receiving portion provided in the flow path, configured such that the fluid flowing from the upstream side of the fluid resistance element strikes against it and causes the fluid to flow sideways, a flexible member that supports the fluid resistance element and deforms according to the flow rate of the fluid, a displacement sensor that measures the displacement of the flexible member, a flow rate calculation unit that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor, and a flow rate measurement mechanism configured such that the fluid flowing sideways by the fluid receiving portion flows through the resistance flow path of the fluid resistance element.

2. The fluid resistance element is composed of a laminate, and the resistance flow path is formed in a direction intersecting the lamination direction thereof, The flexible member supports an upstream portion of the fluid resistance element. The flow rate measurement mechanism according to claim 1.

3. The fluid resistance element is formed with a fluid introduction portion in which a start end of the resistance flow path opens at a central portion thereof as viewed from the lamination direction, and the resistance flow path extends from the fluid introduction portion toward an outer peripheral portion, The fluid receiving portion is provided facing the fluid introduction portion on the downstream side of the central portion of the fluid resistance element. The flow rate measurement mechanism according to claim 1 or 2.

4. The flexible member has an upstream flexible member and a downstream flexible member that support the fluid resistance element with the fluid resistance element interposed therebetween, No through hole is formed in the downstream flexible member, and the fluid flows out from between the upstream flexible member and the downstream flexible member. The flow rate measurement mechanism according to any one of claims 1 to 3.

5. The upstream flexible member is formed with a through hole for allowing the fluid to flow into the fluid resistance element, The fluid that has passed through the fluid resistance element flows out from between the upstream flexible member and the downstream flexible member. The flow rate measurement mechanism according to claim 4.

6. The downstream flexible member has a flat plate shape, The displacement sensor measures the displacement of the downstream flexible member. The flow rate measurement mechanism according to claim 4 or 5.

7. The displacement sensor is provided outside the fluid resistance element between the upstream flexible member and the downstream flexible member. The flow rate measurement mechanism according to claim 4 or 5.

8. An annular spacer member is further provided between the upstream flexible member and the downstream flexible member so as to surround the periphery of the fluid resistance element. The flow rate measuring mechanism according to any one of claims 4 to 7, wherein an outflow passage through which the fluid that has passed through the fluid resistance element passes is formed in the spacer member.

9. A magnetic force adjusting mechanism for adjusting the displacement of the flexible member or the fluid resistance element by magnetic force is further provided. The flow rate calculating unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor and the magnetic force by the magnetic force adjusting mechanism. The flow rate measuring mechanism according to any one of claims 1 to 8.

10. A fluid resistance element provided in a flow path through which a fluid flows and having a resistance flow path formed therein; A flexible member that supports the fluid resistance element and deforms according to the flow rate of the fluid; A displacement sensor that measures the displacement of the flexible member or the fluid resistance element; A magnetic force adjusting mechanism for adjusting the displacement of the flexible member or the fluid resistance element by magnetic force; A flow rate measuring mechanism including a flow rate calculating unit that calculates the flow rate of the fluid based on the displacement measured by the displacement sensor.

11. A magnet on which the magnetic force acts is provided on the flexible member or the fluid resistance element. The flow rate measuring mechanism according to claim 10, wherein the magnetic force adjusting mechanism has an electromagnetic coil that generates the magnetic force.

12. The flow rate calculating unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor and the magnetic force by the magnetic force adjusting mechanism. The flow rate measuring mechanism according to claim 10 or 11.

13. A pressure sensor provided upstream of the fluid resistance element in the flow path; A temperature sensor that measures the temperature of the fluid flowing through the flow path is further provided. The flow rate calculating unit calculates the flow rate of the fluid based on the displacement measured by the displacement sensor, the pressure measured by the pressure sensor, and the temperature measured by the temperature sensor. The flow rate measuring mechanism according to any one of claims 1 to 12.

14. A flow rate measuring mechanism according to any one of claims 1 to 13; A fluid control device including a fluid control valve provided upstream or downstream of the flow rate measuring mechanism.

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