JP6738617B2 - Thermal actuators, thermal valves, and mass flow controllers - Google Patents

Description

The present invention relates to a thermal actuator, a thermal valve, and a mass flow controller used for semiconductor manufacturing equipment and the like.

Conventionally, there has been proposed a configuration in which an electric current is applied to a heater wire to generate heat, and a metal element around which the heater wire is wound is deformed to control an apparatus. For example, Patent Document 1 discloses a configuration in which an insulating tape is wound around the outer periphery of a cylindrical bimetal, a heater wire is spirally wound around the insulating tape, and a current is passed through the heater wire to bend the bimetal. ing.

JP, 2006-73405, A

By the way, when the configuration disclosed in Patent Document 1 is applied to a thermal actuator of a thermal valve that opens and closes a fluid passage by heating a stem with a heater wire to thermally expand the stem to drive a valve element, the outer circumference of the stem The insulating coating is formed on the entire surface of the. For this reason, even if the stem is heated by the heater wire, the stem is less likely to thermally expand, and it takes time until the valve element is driven, and the responsiveness of the thermal valve deteriorates. Also, it becomes difficult to obtain a desired stroke.

Therefore, it is an object of the present invention to provide a thermal actuator, a thermal valve, and a mass flow controller which have good responsiveness and can obtain a desired stroke.

In order to solve the above-mentioned object, a thermal actuator according to one aspect of the present invention is a thermal actuator for driving a valve body, the stem having the valve body attached to one end, and the stem made of an insulating material. And a heater wire wound around the stem and connected to the heater wire along the spiral insulating portion by contacting only the insulating portion spirally formed on the outer peripheral surface of the And a lead wire.

Further, a thermal valve according to an aspect of the present invention includes a valve body having a valve chamber and a flow path forming portion in which a fluid passage communicating with the valve chamber is formed, and an actuator support portion, and the thermal valve is disposed in the valve chamber. A valve body capable of opening and closing the fluid passage, a stem to which the valve body is attached at one end, an insulating portion formed of an insulating material in a spiral shape on the outer peripheral surface of the stem, and only the insulating portion. A heater wire abutting on and wound around the stem along the spiral insulating portion, a lead wire connected to the heater wire, and fixed to the actuator support portion provided on the other end side of the stem. And a thermal actuator having a fixing portion.

Further, a mass flow controller according to one aspect of the present invention includes a flow rate sensor for measuring a flow rate of a fluid, the above-mentioned thermal valve provided on the downstream side of the flow rate sensor, and the thermal valve based on a measurement result of the flow rate sensor. And a control unit for controlling.

According to the present invention, it is possible to provide a thermal actuator, a thermal valve, and a mass flow controller which have good responsiveness and can obtain a desired stroke.

The whole block diagram of the mass flow controller in which the thermal valve which concerns on this embodiment is an open state is shown. The whole block diagram of a thermal actuator is shown. The whole block diagram of the mass flow controller with a thermal valve closed is shown. The explanatory view of the manufacturing process of a thermal actuator is shown.

A thermal actuator 20, a thermal valve 10, and a mass flow controller 1 according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an overall configuration diagram of a mass flow controller 1 in which a thermal valve 10 according to the present embodiment is in an open state.

As shown in FIG. 1, the mass flow controller 1 mainly includes a body 2, a flow rate sensor 3, a control unit 4, and a thermal valve 10.

The body 2 is made of stainless steel or the like. An inflow passage 2a, a bypass flow passage 2b, a sensor inflow passage 2c, a sensor outflow passage 2d, a joint flow passage 2e, a valve chamber 2f, and an outflow passage 2g are formed in the body 2. The periphery of the portion of the body 2 where the confluent passage 2e and the valve chamber 2f communicate with each other forms a valve seat 2H.

The fluid that has passed through the inflow passage 2a flows into the bypass flow passage 2b. The sensor inflow path 2c branches from the bypass flow path 2b to flow the fluid to the flow rate sensor 3. The sensor outflow path 2d causes the fluid that has passed through the flow rate sensor 3 to flow out. In the joint flow passage 2e, the fluid that has passed through the bypass flow passage 2b and the fluid that has passed through the sensor outflow passage 2d merge.

Further, the bypass flow passage 2b and the sensor inflow passage 2c are configured so that the fluid flows at a predetermined flow rate ratio (for example, 1:2 to 1:1000). A plurality of resistance elements 2I are arranged in the bypass flow passage 2b.

The flow rate sensor 3 is a thermal type flow rate sensor, has a thin tube and a heating coil (not shown), measures the flow rate of the fluid, and outputs the measurement result to the control unit 4.

The control unit 4 controls opening/closing of the thermal valve 10 based on the measurement result of the flow rate of the fluid by the flow rate sensor 3 and the like.

The thermal valve 10 is a normally open valve, and is composed of a body 2 (flow path forming portion), an actuator support portion 11, a valve body 12, and a thermal actuator 20. A portion of the body 2 that forms the valve chamber 2f, the joint passage 2e, and the outflow passage 2g and the actuator support portion 11 constitute a valve body. A portion of the body 2 that forms the valve chamber 2f, the combined flow passage 2e, and the outflow passage 2g corresponds to a flow passage forming portion.

The actuator support portion 11 has a tubular shape, is fixed to the body 2, and has an internal thread formed on the inner periphery of its upper end portion.

The valve body 12 is located in the valve chamber 2f and has a substantially columnar base portion 12B in which an annular groove 12a is formed, and a projection portion 12D protruding downward from a lower surface 12c of the base portion 12B and having a tapered shape (conical shape). Have. An O-ring 13 is attached to the annular groove 12a of the base portion 12B.

FIG. 2 shows an overall configuration diagram of the thermal actuator 20.

The thermal actuator 20 includes a stem 21, an insulating coating 22, a fixing portion 23, a heater wire 24, first and second lead wires 25 and 26, and first and second adhesive portions 27 and 28.

The stem 21 is made of, for example, stainless steel, has a round bar shape, and is attached to the base portion 12B so as to extend upward from the base portion 12B. An insulating coating 22 (see FIG. 4C) made of a resin material or the like is spirally coated on the outer peripheral surface 21 a of the stem 21 over the top and bottom of the stem 21. The insulating coating 22 corresponds to an insulating portion.

The fixing portion 23 has a substantially columnar shape, and an external thread 23A is formed on the outer periphery thereof. The external thread 23A is fixed to the actuator support section 11 by being screwed into the internal thread of the actuator support section 11. The upper end of the stem 21 is attached to the fixed portion 23. Further, the fixed portion 23 is formed with two through holes 23b extending in the vertical direction.

The heater wire 24 is in contact with only the insulating coating 22, and is wound around the stem 21 along the spiral insulating coating 22. That is, the insulating coating film 22 is interposed between the stem 21 and the heater wire 24 to prevent the conduction of current from the heater wire 24 to the stem 21.

The first lead wire 25 penetrates one of the through holes 23 b of the fixing portion 23, and the lower end thereof is located near the upper end of the heater wire 24 wound around the stem 21. The upper end of the heater wire 24 is welded to the first lead wire 25.

The second lead wire 26 penetrates through the other through hole 23 b of the fixing portion 23, and the lower end thereof is located near the lower end of the heater wire 24 wound around the stem 21. The lower end of the heater wire 24 is welded to the second lead wire 26.

The first adhesive portion 27 is made of, for example, a resin adhesive and covers the welded portions of the first lead wire 25 and the heater wire 24 and the vicinity of the welded portion of the stem 21.

The second adhesive portion 28 is made of, for example, a resin adhesive, and covers the welded portion of the second lead wire 26 and the heater wire 24 and the vicinity of the welded portion of the stem 21.

In the thermal actuator 20 configured in this way, the heater wire 24 generates heat by causing an electric current to flow through the heater wire 24 via the first and second lead wires 25 and 26 based on the control signal from the controller 4. The heat of the heater wire 24 is transmitted to the stem 21 through the insulating coating 22, and the stem 21 is thermally expanded and expanded. As a result, as shown in FIG. 3, the protrusion 12D of the valve body 12 contacts the valve seat 2H of the body 2 and the fluid passage of the body 2 is closed.

Next, a method for manufacturing the thermal actuator 20 will be described with reference to FIG.

FIG. 4 shows an explanatory diagram of the manufacturing process of the thermal actuator 20.

As shown in FIG. 4A, the stem 21 is fixed to the valve body 12 by welding or the like. As shown in FIG. 4B, masking is performed on the stem 21 with a masking tape 29 or the like so that the spiral exposed region 21b is formed on the outer peripheral surface 21a thereof. An insulating material such as a resin material is applied and cured on the spiral exposed region 21b of the outer peripheral surface 21a of the stem 21, and the masking tape 29 is peeled off. As shown in FIG. 22 is formed.

As shown in FIG. 4D, the heater wire 24 is brought into contact with only the insulating coating 22 and wound around the stem 21 along the insulating coating 22. The O-ring 13 is attached to the valve body 12. As shown in FIG. 4E, the fixing portion 23 to which the first and second lead wires 25 and 26 are attached is fixed to the upper end of the stem 21 by welding or the like. The upper end of the heater wire 24 is welded to the lower end of the first lead wire 25, and the lower end of the heater wire 24 is welded to the lower end of the second lead wire 26.

As shown in FIG. 4F, a resin adhesive is applied and cured so as to cover the welded portions of the first lead wire 25 and the heater wire 24 and the vicinity of the welded portions of the stem 21, and the first adhesive is applied. The adhesive portion 27 is formed. A resin adhesive is applied and cured so as to cover the welded portions of the second lead wire 26 and the heater wire 24 and the vicinity of the welded portion of the stem 21 to form the second adhesive portion 28.

In this way, the thermal actuator 20 is manufactured.

As described above, in the thermal actuator 20 of the thermal valve 10 of the present embodiment, the insulating coating 22 is spirally formed on the outer peripheral surface 21 a of the stem 21, and the heater wire 24 is in contact with only the insulating coating 22 to form the spiral coating. The stem 21 is wound around the insulating coating 22.

With such a configuration, the insulating coating 22 is formed only on a necessary portion of the stem 21, not on the entire outer peripheral surface 21a of the stem 21, so that the responsiveness of the thermal actuator 20 can be improved and a desired stroke can be obtained. Can be obtained. Further, since the mass flow controller 1 has the thermal valve 10, it is possible to provide the mass flow controller 1 that is inexpensive and is compatible with a minute flow rate and a high magnetic field.

The present invention is not limited to the above embodiment. Those skilled in the art can make various additions and changes within the scope of the present invention.

For example, the thermal valve 10 is normally open, but may be normally closed. Instead of the insulating coating 22, an insulating tape may be wrapped around the stem 21. The valve seat 2H may be formed separately from the body 2 and made of a different material. Further, the actuator support portion 11 is not limited to a tubular shape, and may be a hollow cube (not shown).

1: Mass flow controller 2: Body 2e: Joint flow path 2f: Valve chamber 2g: Outflow path 3: Flow rate sensor 10: Thermal valve 11: Actuator support 12: Valve body 20: Thermal actuator 21: Stem
21a: outer peripheral surface 22: insulating coating 24: heater wire 25: first lead wire 26: second lead wire

Claims (3)

A thermal actuator for driving the valve body,
A stem to which the valve body is attached at one end,
An insulating portion which is made of an insulating material and is formed in a spiral shape so that a spiral exposed region is formed on the outer peripheral surface of the stem;
A heater wire that is in contact with only the insulating portion and is wound around the stem along the spiral insulating portion,
And a lead wire connected to the heater wire. A valve body having a valve chamber and a flow passage forming portion in which a fluid passage communicating with the valve chamber is formed; and an actuator support portion,
A valve body arranged in the valve chamber and capable of opening and closing the fluid passage,
A stem to which the valve body is attached at one end, an insulating portion formed of an insulating material and formed in a spiral shape so as to form a spiral exposed region on the outer peripheral surface of the stem, and abutting only on the insulating portion. Heater wire wound around the stem along the spirally shaped insulating portion, a lead wire connected to the heater wire, and a fixing portion provided on the other end side of the stem and fixed to the actuator supporting portion. And a thermal actuator having: A flow rate sensor that measures the flow rate of the fluid,
The thermal valve according to claim 2, which is provided on the downstream side of the flow rate sensor,
A control unit that controls the thermal valve based on the measurement result of the flow rate sensor.

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