Fluid control device, vaporization system, and piezo actuator

Abstract

The present invention provides a fluid control device, a vaporization system and a piezoelectric actuator to prevent cracking of the piezoelectric element and reduce the thermal impact on the control board. The fluid control device includes: a fluid control valve (3) driven by a piezoelectric actuator (32); a fluid sensor (4) for measuring the pressure or flow rate of the fluid; a control board (5) for controlling the fluid control valve (3) based on the measured value measured by the fluid sensor (4); and a discharge resistor (7) disposed in a component different from the control board (5).

Description

[Technical Field]

[0001] The present invention relates to a fluid control device, a vaporization system using the fluid control device, and a piezoelectric actuator for the same. [Previous Technology]

[0002] As shown in Patent Document 1, as a conventional fluid control device, a fluid control device that uses a piezoelectric actuator as a fluid control valve can be considered.

[0003] The piezoelectric actuator has a piezoelectric stack consisting of many piezoelectric elements stacked together. If a piezoelectric element cracks, a short circuit will occur between the piezoelectric elements, leading to failure.

[0004] In addition to impacts caused by external forces, the crack can also be caused by rapid charging and discharging of the piezoelectric element. Therefore, in order to prevent rapid charging and discharging, the following countermeasures are taken: a discharge resistor is mounted on the control board, and the discharge resistor is connected in parallel with the positive and negative terminals of the piezoelectric actuator.

[0005] In addition, as a reason for charging and discharging, besides the voltage applied from the control board and the discharge, the pyroelectric effect caused by temperature change and the piezoelectric effect caused by external force can also be cited.

[0006] However, if a discharge resistor is provided in the control board, the resistive heating caused by the discharge resistor will have an adverse effect on other components mounted on the control board.

[0007] Existing Technical Documents

[0008] Patent Document 1: International Publication No. 2020 / 066491 [Summary of the Invention]

[0009] Therefore, the present invention was made in view of the above-mentioned problems, and the main object of the present invention is to prevent cracks in the piezoelectric element and reduce the thermal impact on the control substrate.

[0010] That is, the fluid control device of the present invention is characterized by comprising: a fluid control valve driven by a piezoelectric actuator; a fluid sensor for measuring the pressure or flow rate of a fluid; a control board for controlling the fluid control valve based on the measured value measured by the fluid sensor; and a discharge resistor disposed in a component different from the control board.

[0011] In such a fluid control device, even if the piezoelectric element is charged due to the pyroelectric effect caused by temperature changes or the piezoelectric effect caused by external force, it can be discharged through the discharge resistor each time, thus preventing cracks in the piezoelectric element. In addition, since the discharge resistor is placed in a component different from the control board, the thermal impact of the resistance heating of the discharge resistor on the control board can be reduced.

[0012] As a simple connection method for discharging the piezoelectric actuator, it is preferable that the discharge resistor is connected in parallel with the piezoelectric actuator.

[0013] When a fluid control device is used in a high-temperature environment, the heat resistance of the control board becomes a problem. Therefore, in order to enable the fluid control device to be used even in a high-temperature environment, it is preferable that the main body unit having the fluid control valve and the fluid sensor is separated from the control board, and the discharge resistor is disposed in the main body unit.

[0014] Preferably, the discharge resistor is disposed at a power supply terminal extending from the housing of the piezoelectric actuator that houses the piezoelectric stack.

[0015] If this configuration is used, visual inspection becomes easier in the event of a malfunction in the discharge resistor. Furthermore, the assembly of the discharge resistor also becomes easier.

[0016] Specifically, preferably, the discharge resistor is obtained by forming a resistive film on a substrate made of an insulating material such as ceramic, and a through hole is formed on the substrate for mounting to the power supply terminal.

[0017] With this configuration, a reliable conductive connection can be made to the power supply terminal portion through the through-hole. In addition, by forming a gap and placing the substrate between the piezoelectric stack and the resistive film of the piezoelectric actuator, the effect of resistive heating on the piezoelectric stack can be reduced.

[0018] Preferably, the discharge resistor is disposed inside the housing of the piezoelectric actuator containing the piezoelectric stack.

[0019] If this configuration is used, since the discharge resistor is placed inside the piezoelectric actuator, the assembly of the fluid control device can be the same as in the past.

[0020] Preferably, the main unit has a connecting cable or connector connected to the control board, and the discharge resistor is disposed on the connecting cable or the connector.

[0021] With this configuration, visual inspection becomes easier in the event of a malfunction in the discharge resistor. Furthermore, since it is sufficiently isolated from the piezoelectric stack, the impact of resistor heating on the piezoelectric stack can be reduced. In addition, the discharge resistor can be kept away from high-temperature environments, eliminating the need for expensive discharge resistors with heat resistance.

[0022] Preferably, the main body unit has an internal substrate for processing signals from the fluid sensor, and the discharge resistor is disposed on the internal substrate.

[0023] With this configuration, the discharge resistor can be placed inside the main unit. Furthermore, by placing the discharge resistor on the internal substrate, assembly becomes easier. In addition, visual inspection becomes easier in the event of a malfunction in the discharge resistor.

[0024] In addition, the vaporization system of the present invention is characterized by comprising: a vaporization section for vaporizing liquid materials; and the above-described fluid control device for controlling the flow rate of gas obtained by vaporization through the vaporization section.

[0025] Furthermore, preferably, the piezoelectric actuator of the present invention is used to drive the fluid control valve of a fluid control device, the fluid control device comprising: the fluid control valve; a fluid sensor for measuring the pressure or flow rate of a fluid; a control board for controlling the fluid control valve based on the measured value measured by the fluid sensor; and a discharge resistor disposed in a component different from the control board, the discharge resistor being connected in parallel with a power supply terminal portion extending from the housing of the piezoelectric actuator that houses the piezoelectric stack.

[0026] As a specific embodiment of the discharge resistor, it is conceivable that the discharge resistor is formed by forming a resistive film on a substrate made of insulating material. In this configuration, it is preferable that a through hole is formed on the substrate for mounting to the power supply terminal portion.

[0027] According to the present invention described above, cracks in the piezoelectric element can be prevented and the thermal impact on the control substrate can be reduced.

Implementation Method

[0029] Embodiments of the present invention will be described below with reference to the accompanying drawings. Furthermore, all figures shown below have been appropriately omitted or depicted schematically with exaggerated representations for ease of understanding. The same reference numerals are assigned to the same components, and descriptions are appropriately omitted.

[0030] <First Embodiment>

[0031] First, an embodiment of the fluid control device of the present invention will be described with reference to the accompanying drawings.

[0032] <Device Configuration>

[0033] The fluid control device 100 in this embodiment is a so-called mass flow controller, for example, used to control the flow rate of gas supplied to the chamber where the semiconductor manufacturing process is carried out. In addition, the fluid control device 100 can control not only gas, but also liquid.

[0034] Specifically, as shown in FIG1, the fluid control device 100 includes: a main body 2 having a flow channel R formed therein; a fluid control valve 3 for controlling the fluid in the flow channel R; a flow sensor 4 for measuring the flow rate in the flow channel R; and a control board 5 for controlling the fluid control valve 3 based on the measured value measured by the flow sensor 4.

[0035] As shown in FIG. 1, the fluid control valve 3 and the flow sensor 4 of this embodiment are mounted on one side (e.g., the upper surface) of the main body 2 and housed within a housing 6 mounted on one side of the main body 2. Thus, the fluid control valve 3 and the flow sensor 4 are integrated as a main body unit 10. Furthermore, the control unit 20, which has a control board 5, is separately disposed from the main body unit 10 and is connected via a connecting cable K for controlling various parts of the main body unit 10. Additionally, the connecting cable K is detachably connected at least with respect to the control unit 20.

[0036] In this configuration, when the fluid control device 100 is used in a high-temperature environment, the main unit 10 is used in the high-temperature environment while the control unit 20 is removed from the high-temperature environment and placed separately. This solves the problem of the heat resistance of the control board 5. Furthermore, the fluid control device 100 is packaged and installed separately as the main unit 10 and the control unit 20 during transportation and installation.

[0037] The fluid control valve 3 is a so-called piezoelectric valve, whose opening degree is controlled according to the applied voltage. Specifically, the fluid control valve 3 includes: a valve mechanism 31, which consists of a valve seat 31a and a valve body 31b housed in a recess formed on the upper surface of the main body 2; a piezoelectric actuator 32, which exerts a driving force to change the position of the valve body 31b relative to the valve seat 31a; and a plunger 33, which connects the valve mechanism 31 and the piezoelectric actuator 32. In addition, the fluid control valve 3 of this embodiment is a normally open valve, but it can also be a normally closed valve. Furthermore, the configuration of the valve mechanism 31 is not limited to the above; it can also be configured to house the valve seat 31a or the valve body 31b in a recess formed on the upper surface of the main body 2, or it can be configured to have the valve seat formed on the upper surface of the main body 2.

[0038] The piezoelectric actuator 32 includes: a piezoelectric stack 32a, which is composed of a plurality of plate-shaped piezoelectric elements that extend in the thickness direction through energization; and a housing 32b that houses the piezoelectric stack 32a. Each piezoelectric element is composed of a plate-shaped piezoelectric ceramic body and electrode bodies disposed on both sides of the piezoelectric ceramic body. The piezoelectric actuator 32 is voltage-driven by a drive circuit (not shown). In addition, the drive circuit outputs a voltage according to the command voltage output from the control board 5.

[0039] The flow sensor 4 is a thermal flow sensor, comprising: a flow divider element (resistance element) 41 disposed on the flow channel R; a thin tube 42 branching from the upstream side of the flow divider element 41 and converging at the downstream side of the flow divider element 41; two heating coils 43 wound around the thin tube 42 and subjected to voltage in a manner that maintains them at a certain temperature; and a detection circuit 44 that detects the difference in voltage applied to each heating coil 43. This flow sensor 4 is disposed on the upstream or downstream side of the fluid control valve 3 on the flow channel R. In addition to being thermal, the flow sensor 4 can also be, for example, a pressure type.

[0040] The control board 5 controls the fluid control valve 3 based on the measured flow rate measured by the flow sensor 4. The control board 5 is a computer equipped with a CPU, memory, A / D converter, D / A converter, and various input / output devices. By executing the fluid control program stored in the memory, the CPU and peripheral devices cooperate to perform the functions of the flow calculation unit 51 and the valve control unit 52, etc.

[0041] The flow calculation unit 51 calculates the flow rate of the gas flowing through the flow channel R based on the output of the detection circuit 44 of the flow sensor 4.

[0042] The valve control unit 52 controls the opening degree of the fluid control valve 3 based on the command flow rate input from the outside and the measured flow rate measured by the flow sensor 4. Specifically, the valve control unit 52 controls the opening degree of the fluid control valve 3 in a manner that minimizes the deviation between the command flow rate and the measured flow rate. In this embodiment, the valve control unit 52 performs PID calculation on the deviation between the command flow rate and the measured flow rate, and outputs a command voltage corresponding to the result of the PID calculation to the drive circuit of the piezoelectric actuator 32. The drive circuit applies a voltage corresponding to the input command voltage to the piezoelectric stack 32a.

[0043] <Composition of the discharge resistor 7>

[0044] As described above, the fluid control device 100 is packaged and installed as a main unit 10 and a control unit 20 during transportation and installation. Especially during transportation, large temperature changes cause the piezoelectric stack 32a to charge due to the pyroelectric effect. Furthermore, the piezoelectric effect caused by vibration during transportation charges the piezoelectric stack 32a. Subsequently, for example, during installation, a rapid discharge may occur due to a short circuit in the piezoelectric stack 32a, potentially causing cracks in the piezoelectric elements of the piezoelectric stack 32a.

[0045] Therefore, as shown in Figures 2 to 6, the fluid control device 100 of this embodiment also includes a discharge resistor 7 provided in a component different from the control board 5. This discharge resistor 7 is provided in the main body unit 10 and is connected in parallel with the piezoelectric actuator 32.

[0046] Because the discharge resistor 7 is configured in this way, even if the piezoelectric stack 32a is charged due to pyroelectric effect caused by temperature change or piezoelectric effect caused by external force, it can still be discharged through the discharge resistor 7. As a result, cracks in the piezoelectric elements of the piezoelectric stack 32a can be prevented. In addition, since the discharge resistor 7 is located in a component different from the control board 5, the thermal impact of the resistive heating of the discharge resistor 7 on the control board 5 can be reduced.

[0047] The specific structure of the discharge resistor 7 will be explained below.

[0048] In the configuration shown in FIG2(a), the discharge resistor 7 is provided at the power supply terminal portion 32c extending from the housing 32b of the piezoelectric actuator 32, which houses the piezoelectric stack 32a. This power supply terminal portion 32c is a so-called sealed terminal, extending from the upper surface of the housing 32b, and is composed of a positive terminal 32c1 and a negative terminal 32c2. Furthermore, the discharge resistor 7 is connected to the positive terminal 32c1 and the negative terminal 32c2.

[0049] Specifically, as shown in Figures 2(a) and 2(b), the discharge resistor 7 is constructed, for example, by forming a resistive film 72 on a substrate 71 made of an insulating material such as ceramic. As shown in Figure 2(b), the substrate 71 is generally rectangular in shape when viewed from above, and a through-hole 71h is formed on the substrate 71 for mounting the power supply terminal portion 32c. The through-hole 71h is a semi-circular shape formed on opposite sides of the substrate 71. The discharge resistor 7 thus constructed is disposed between the positive terminal 32c1 and the negative terminal 32c2, and the positive terminal 32c1 and the negative terminal 32c2 are respectively embedded in two through-holes 71h. Furthermore, the discharge resistor 7 is soldered to the positive terminal 32c1 and the negative terminal 32c2 through the through-holes 71h.

[0050] Here, the resistance value of the resistive film 72 formed on the substrate 71 of the discharge resistor 7 can be changed to various resistance values ​​according to the insulation resistance of the piezoelectric actuator 32. For example, the resistance value of the resistive film 72 can be 1MΩ, 10MΩ, or 100MΩ. These resistance values ​​can be set by changing the printed pattern of the resistive film 72. In addition, from the point of view of universality, the shape of the substrate 71 (including the through hole 71h) is the same regardless of the different resistance values ​​of the resistive film 72.

[0051] In addition, the discharge resistor 7 may be configured to have a resistor film 72 formed on the substrate 71, or it may be configured to have a resistor mounted on the substrate 71, as shown in FIG3. Alternatively, it may be configured to not have a substrate 71 but to connect the resistor to the positive terminal 32c1 and the negative terminal 32c2.

[0052] If the configuration shown in Figure 2 is used, a reliable conductive connection can be made through the through-hole 71h. Furthermore, if the configurations shown in Figures 2 and 3 are used, visual inspection becomes easier in the event of poor conductivity of the discharge resistor 7. Additionally, by positioning the gap or substrate 71 between the piezoelectric actuator 32 (piezoelectric stack 32a) and the resistive film 72, the impact of resistor heating on the piezoelectric stack 32a can be reduced.

[0053] In the configuration shown in FIG. 4, the discharge resistor 7 is disposed within the housing 32b of the piezoelectric actuator 32, which houses the piezoelectric stack 32a. Specifically, the discharge resistor 7 is connected to the positive terminal 32c1 and the negative terminal 32c2 of the power supply terminal portion 32c extending into the housing 32b. Furthermore, if it is inside the housing 32b, the discharge resistor 7 may also be connected to the internal wiring connected to the power supply terminal portion 32c.

[0054] If it is the configuration shown in Figure 4, since the discharge resistor 7 is placed inside the piezoelectric actuator 32, the fluid control device 100 can be assembled in the same way as before.

[0055] In the configuration shown in FIG5, the discharge resistor 7 is provided in the connection cable K or connector C of the main body unit 10. When the discharge resistor 7 is provided in the connection cable K or connector C, the discharge resistor 7 is connected to the power line K1 connected to the power supply terminal 32c of the piezoelectric actuator 32 in the connection cable K or connector C. FIG5(a) is an example of connecting the discharge resistor 7 to the power line K1 of the connection cable K, and FIG5(b) is an example of connecting the discharge resistor 7 to the power line K1 of the connector C.

[0056] If the configuration shown in Figure 5 is used, the discharge resistor 7 is connected to the power supply line K1, making assembly easier. Furthermore, visual inspection is easier in the event of a malfunction in the discharge resistor 7. Additionally, since it can be sufficiently isolated from the piezoelectric stack 32a, the impact of resistor heating on the piezoelectric stack 32a can be reduced. Moreover, the discharge resistor 7 can be kept away from high-temperature environments, eliminating the need for a high-cost, heat-resistant discharge resistor 7.

[0057] In the configuration shown in FIG. 6, a discharge resistor 7 is provided on a relay board 8 provided in the main body unit 10. The relay board 8 is an internal board that processes signals from the flow sensor 4 and relays the power line K1 of the connecting cable K. The relay board 8 has a connecting pin 81 for connecting the power line K1, and the discharge resistor 7 is connected to the connecting pin 81.

[0058] If the configuration shown in Figure 6 is used, the discharge resistor 7 can be placed inside the main unit 10. Furthermore, since the discharge resistor 7 is connected to the relay board 8, assembly becomes easier. Additionally, visual inspection is easy in the event of a malfunction in the discharge resistor 7.

[0059] <Second Embodiment>

[0060] Next, an embodiment of a vaporization system in which the fluid control device of the present invention is assembled will be described with reference to the accompanying drawings.

[0061] The vaporization system 1000 of this embodiment is assembled, for example, into a semiconductor manufacturing line, for supplying a predetermined flow rate of gas to a chamber where semiconductor manufacturing processes are performed. As shown in FIG7, the vaporization system 1000 includes: a vaporization section 200 for vaporizing liquid materials; a fluid control device 100 for controlling the flow rate of gas vaporized through the vaporization section 200; and a control device 400 for controlling the operation of the vaporization section 200 and the fluid control device 100. Furthermore, the configuration of the fluid control device 100 is the same as in the first embodiment.

[0062] In this embodiment, the vaporization unit 200 and the fluid control device 100 are housed in a common housing 500, thereby forming a vaporization unit 600, and the control device 400 is provided separately from the vaporization unit 600. In addition, the vaporization unit 600 and the control device 400 are connected by a connecting cable K for controlling each part of the vaporization unit 600.

[0063] The vaporization unit 200 includes: a vaporizer 201, which vaporizes liquid material, for example, by means of heat drying; a supply quantity controller 202, which controls the supply quantity of liquid material to the vaporizer 201; and a preheater 203, which preheats the liquid material supplied to the vaporizer 201 to a predetermined temperature.

[0064] These vaporizers 201, supply controllers 202, and preheaters 203 are mounted on a device mounting surface Bx, which is located on a surface of a main body block B in which flow channels R are formed internally. Here, the main body block B is made of a metal such as stainless steel and has a generally cuboid shape with its long side facing upwards. The main body block B is mounted on a semiconductor manufacturing line or the like with the liquid material inlet P1 located on the lower side and the vaporized gas outlet P2 located on the upper side, and its long side facing upwards and downwards (vertically).

[0065] The vaporizer 201 includes: a storage container 201a, which is a vaporization tank for storing liquid material inside; and a vaporization heater 201b disposed in the storage container 201a for vaporizing the liquid material. A liquid level sensor 201c for detecting the amount of stored liquid material is disposed in the storage container 201a.

[0066] The supply quantity controller 202 is a control valve that controls the supply flow rate of liquid material to the vaporizer 201. In this embodiment, it is an electromagnetic switch valve. Specifically, the valve body of the electromagnetic switch valve 202 (not shown) supplies or stops the supply of liquid material to the vaporizer 201 by opening or closing an opening formed in the internal flow channel of the main body block B.

[0067] The preheater 203 includes: a preheating block 203a, in which a flow channel for liquid material is formed; and a preheating heater 203b disposed in the preheating block 203a for preheating the liquid material. Through the preheater 203, the liquid material is heated to a temperature (below the boiling point) just before it vaporizes.

[0068] Through the vaporization section 200 configured as shown above, the liquid material introduced from the liquid material inlet P1 flows through the flow channel of the preheating block 203a of the preheater 203, thereby being preheated to a predetermined temperature. By controlling the solenoid valve 202, which serves as a supply quantity controller, the liquid material preheated by the preheater 203 is introduced into the vaporizer 201. Furthermore, the vaporizer 201 is always in a state where liquid material is stored, and the liquid material vaporizes, continuously generating vaporized gas of the liquid material, which is continuously discharged to the fluid control device 100.

[0069] The fluid control device 100 is mounted on a device mounting surface Bx on one side of the main body block B, similar to the vaporization unit 200. Specifically, the fluid control device 100 is located on the main body block B downstream of the vaporization unit 200. The configuration of this fluid control device 100 is the same as in the first embodiment.

[0070] The control device 400 controls the vaporization operation of the liquid material in the vaporization system 1000. Specifically, the control device 400 is configured to supply liquid material to the vaporizer 201 during vaporization operation by controlling the aforementioned electromagnetic switching valve 22. Furthermore, the control device 400 is configured to control the fluid control valve 3 based on the measured flow rate measured by the flow sensor 4. This control device 400 includes the control board 5 of the first embodiment.

[0071] In this vaporization system 1000, the configuration of the discharge resistor 7 provided in the fluid control device 100 is also the same as in the first embodiment.

[0072] Specifically, the configuration of placing the discharge resistor 7 in the power supply terminal 32c of the piezoelectric actuator 32 is the same as that in FIG2 or FIG3, and the configuration of placing the discharge resistor 7 inside the housing 32b of the piezoelectric actuator 32 is the same as that in FIG4.

[0073] Furthermore, in FIG5, the main body unit 10 is replaced by the vaporization unit 600, and the discharge resistor 7 is provided in the connecting cable K or connector C of the vaporization unit 600. In addition, in FIG6, the discharge resistor 7 is provided in the relay board 8 provided in the vaporization unit 600.

[0074] <Other Implementation Methods>

[0075] For example, in each of the embodiments, the fluid sensor is a flow sensor that measures the flow rate of the fluid, but it may also be a pressure sensor that measures the pressure of the fluid.

[0076] In addition, the discharge resistor 7 can be connected in series with the piezoelectric actuator 32 (piezoelectric stack 32a) in a configuration that allows the piezoelectric stack 32a to be discharged when connected to the control power supply or when the signal line of the piezoelectric stack is short-circuited.

[0077] Furthermore, in the above embodiment, the fluid control device 100 is configured such that the main unit 10 and the control board 5 are separate, but it may also be configured such that the main unit 10 and the control board 5 are not separate. Specifically, the control board 5 may also be integrated and housed within the housing 6.

[0078] Furthermore, various modifications and combinations of embodiments are possible as long as they do not violate the spirit of the present invention. [Simplified Explanation of the Diagram]

[0028] FIG1 is a schematic diagram showing the configuration of the fluid control device according to the first embodiment of the present invention. FIG2 is a schematic diagram showing Embodiment 1 of the discharge resistor of the same embodiment. FIG3 is a diagram showing a modified example of Embodiment 1. FIG4 is a schematic diagram showing Embodiment 2 of the discharge resistor of the same embodiment. FIG5 is a schematic diagram showing Embodiment 3 of the discharge resistor of the same embodiment. FIG6 is a schematic diagram showing Embodiment 4 of the discharge resistor of the same embodiment. FIG7 is a schematic diagram showing the configuration of the vaporization system in which the fluid control device of the present invention is assembled.

Claims

1. A fluid control device, characterized in that the fluid control device comprises: a fluid control valve driven by a piezoelectric actuator; a fluid sensor for measuring the pressure or flow rate of a fluid; a control board for controlling the fluid control valve based on the measured value measured by the fluid sensor; and a discharge resistor disposed in a component different from the control board; wherein the discharge resistor is disposed at a power supply terminal extending from a housing of the piezoelectric actuator that houses a piezoelectric stack.

2. The fluid control device as claimed in claim 1, wherein the discharge resistor is connected in parallel with the piezoelectric actuator.

3. The fluid control device according to claim 1, characterized in that the discharge resistor is formed by forming a resistive film on a substrate made of insulating material, and a through hole for mounting to the power supply terminal is formed on the substrate.

4. A fluid control device, characterized in that the fluid control device comprises: a fluid control valve driven by a piezoelectric actuator; a fluid sensor for measuring the pressure or flow rate of a fluid; a control board for controlling the fluid control valve based on the measured value measured by the fluid sensor; and a discharge resistor disposed in a component different from the control board; wherein a main unit comprising the fluid control valve and the fluid sensor housed within a housing, and the control board disposed separately from the main unit outside the housing, are connected via a connecting cable or connector, and the discharge resistor is disposed within the housing of the main unit.

5. The fluid control device as claimed in claim 4, characterized in that the main body unit has an internal substrate for processing signals from the fluid sensor, and the discharge resistor is disposed on the internal substrate.

6. A vaporization system, characterized in that the vaporization system comprises: a vaporization section for vaporizing a liquid material; and a fluid control device for controlling the flow rate of gas obtained by vaporization through the vaporization section, wherein the fluid control device is the fluid control device described in any one of claims 1 to 5.

7. A piezoelectric actuator, characterized in that the piezoelectric actuator is used to drive a fluid control valve of a fluid control device, the fluid control device comprising: the fluid control valve; a fluid sensor for measuring the pressure or flow rate of a fluid; a control board for controlling the fluid control valve based on the measured value measured by the fluid sensor; and a discharge resistor disposed in a component different from the control board, the discharge resistor being connected in parallel with a power supply terminal portion extending from a housing of the piezoelectric actuator that houses a piezoelectric stack.

8. The piezoelectric actuator as claimed in claim 7, characterized in that the discharge resistor is formed by forming a resistive film on a substrate made of insulating material, and a through hole for mounting to the power supply terminal is formed on the substrate.

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