JP4499984B2 - High temperature valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a valve that is incorporated in a variable flow valve or the like and performs flow restriction for adjusting a flow rate, and particularly relates to a high-temperature compatible valve that can control a high-temperature fluid.
[0002]
[Prior art]
FIG. 5 is a diagram illustrating an example of a flow control valve 20 that combines a flow sensor and a flow control valve in order to control the flow rate of the fluid to be controlled. In FIG. 5, 2 is a valve block having flow paths 2a and 2b formed therein, and 3 is a diaphragm valve that contacts and opens the open ends of both flow paths 2a and 2b on one surface of the valve block 2, for example. 4 is a spacer that fixes the outer periphery of the valve body 3 so as to hold down the outer periphery of the valve body 3, and 5 is a piezo stack made of a piezoelectric element that contacts the operation portion 3a of the valve body 3 and controls the opening and closing of the valve body 3 by expansion and contraction. , 6 is a cover of the piezo stack 5, 7 is a spacer press that forms a convex portion 7 a that fits into the concave portion 4 a of the spacer 4, and the cover 6 is screwed to the inner peripheral portion, and 8 is a spacer press 7, spacer 4 Is a tightening screw that fixes the spacer retainer 7 and the spacer 4 by screwing into a female thread portion formed in the valve block 2.
[0003]
By using the piezo stack 5 as the actuator 1B of the flow control valve 20 as described above, the piezo stack 5 has a very high response, so that high speed flow control can be performed. In addition, since the structure of the valve block 2, the valve body 3, and the spacer 4 can be considered variously, in this specification, the structure which consists of these members 2-4 is expressed as the valve base 1A. Similarly, various configurations of the piezo stack 5 and its cover 6 and the spacer presser 7 are also conceivable. Therefore, the piezo stack 5 for operating the valve body 3 and its cover 6 and, further, in the case of this example, the spacer presser 7. Is added to represent the actuator 1B. Various fluids can be conceived as a control target of the flow control valve 20 having the above-described configuration, and in particular, a flow control valve incorporated in a semiconductor process may control a high-temperature fluid.
[0004]
[Problems to be solved by the invention]
However, the upper limit temperature at which the piezo stack 5 as the actuator 1B of the flow control valve can be operated is 120 ° C., and if this temperature is exceeded, the amount of elongation becomes extremely small, so that it does not operate. For this reason, when the piezo stack 5 is used for the actuator 1B of the flow control valve 20 for the high temperature process, for example, when a high temperature fluid of 200 ° C. is used, the piezo stack portion of the conventional type is 150 ° C. Therefore, it could not be used because it exceeded the operable upper limit temperature.
[0005]
Further, if a heat sink having a high heat dissipation effect is provided between the valve base 1A and the actuator 1B, a heat sink having a high heat dissipation effect generally has a high heat transfer rate, so that heat from the valve block 2 is easily transferred to the piezo stack 5. It is considered that this is adversely affected on the piezo stack 5. In addition, since a heat sink having a high heat dissipation effect is generally formed of a metal such as aluminum, there is a problem that its thermal expansion is large. That is, since the elongation of the piezo stack 5 is only about 50 μm, the thermal expansion of the heat sink becomes larger than the operation amount of the piezo stack 5 and cannot be used.
[0006]
The present invention has been made in consideration of the above-described matters, and an object of the present invention is to provide a high-temperature compatible valve that can accurately control the flow rate even for a fluid to be controlled at a high temperature. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a high temperature compatible valve according to the present invention has a valve base including a valve body that opens and closes a flow path of a fluid to be controlled, and operates an operation portion of the valve body attached to the valve base. A valve having an actuator equipped with a piezo stack, and having a spacer main body that is located between the actuator and the valve base so as to transmit the operation of the piezo stack to the valve body and to dissipate the heat transmitted from the valve body side. The spacer body is made of a material having a thermal expansion coefficient equal to or lower than that of the piezo stack. (Claim 1)
[0008]
That is, if the flow control hot controlled object by using the high temperature corresponding valve, the spacer body ho fluid to be controlled in a portion in contact with the valve body Isuzu becomes the same degree of temperature, the temperature gradient within the spacer body In the part that comes into contact with the piezo stack, the temperature becomes low. Thus, the piezo stack prevents receives heat from the fluid of the control object directly, the portion where the piezoelectric stack of the spacer body is in contact is lower than the temperature of the fluid in response to temperature gradients caused by the spacer body, the more hot fluid The flow rate can be controlled.
[0009]
Even if the spacer body receives heat from the fluid to be controlled and expands, the coefficient of thermal expansion is made of a material that is the same as or smaller than the coefficient of thermal expansion of the piezo stack. It does not become larger than the operation amount. That is, it is possible to prevent a situation where the flow rate control becomes impossible due to the thermal expansion of the spacer body .
[0010]
The spacer body has a rod-shaped first member that connects the operation portion of the piezo stack and the operation portion of the valve body, a through hole that slidably accommodates the first member, and an outer peripheral portion of the actuator and the valve base. It consists of a second member having a predetermined length to join at regular intervals, to to be the same as the length if the length of the first member and the second member (claim 2), By sandwiching the spacer main body between the valve base and the actuator, this can be used as a high temperature compatible valve, and the manufacturing cost can be reduced accordingly.
[0011]
Further, since the second member slidably accommodates the first member, the temperature gradient generated in the first member and the temperature gradient generated in the second member can be made approximately the same. That is, since the thermal expansion generated in the first member and the thermal expansion generated in the second member are approximately the same, the mutual thermal expansion is canceled, and the operation amount by the piezo stack is not affected by the thermal expansion of the spacer body. It can be transmitted to the valve body.
[0012]
When the spacer body is made of a material having a thermal expansion coefficient of 2 × 10 ^{−6 to} 6 × 10 ⁻⁶ [1 / ° C.] or less (Claim 3), the temperature gradient is suppressed while suppressing the length of the spacer. Since it can be taken large, the overall size can be reduced.
[0013]
When the spacer body is made of ceramic (Claim 4), the spacer body is excellent in heat resistance and fastness, and is highly reliable.
[0014]
The spacer body, if having a tubular heat radiating body having cooling fins in a plurality of stages which may the temperature of the spacer body with a temperature gradient and cooling at each location on the outer periphery to the outer periphery (claim 5), heat dissipation Due to the double structure comprising the body and the first member and the second member, the heat dissipation effect of the spacer body can be enhanced and more heat can be radiated. That is, the size of the spacer body for ensuring the operating temperature of the piezo stack can be reduced. In addition, the plurality of cooling fins can cool the temperature of the spacer main body having a temperature gradient at each position.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a high temperature compatible valve 1 according to the present invention. This high temperature compatible valve 1 includes a valve base 1A and an actuator 1B having various configurations similar to the conventional flow control valve 20 shown in FIG. Have Further, in FIG. 1, the portions denoted by the same reference numerals as those in FIG. 5 are the same or equivalent members, and thus detailed description thereof is omitted.
[0016]
In FIG. 1, reference numeral 10 denotes a heat insulating spacer formed by forming a convex portion 10 a that engages with a concave portion 4 b formed in the upper portion of the spacer 4 on the lower surface. The heat insulating spacer 10 is, for example, a rod-shaped first member 11 (hereinafter also referred to as a pressing pin) that connects the operation portion 5a of the piezo stack 5 and the operation portion 3a of the valve body 3, and slides on the first member 11. It has a through hole 12 that can be freely accommodated, and has a predetermined length so that the distance from the outer periphery of the actuator 1B (that is, the outer periphery of the lower end of the cover 6) to the outer periphery of the valve base 1A is constant. A spacer main body 14 composed of the second member 13 and a heat dissipating body having a cylindrical shape with excellent thermal conductivity disposed on the outer periphery of the spacer main body 14 and further provided with a plurality of cooling fins 15a on the outer periphery. Consist of 15.
[0017]
The first member 11 and the second member 13 constituting the spacer body 14 are both made of a material having a thermal expansion coefficient equal to or lower than that of the piezo stack 5, and the piezo stack 5 is formed by laminating ceramics. That is, since the thermal expansion coefficient of ceramics such as ceramic is 2 × 10 ^{−6 to} 6 × 10 ⁻⁶ [1 / ° C.], the spacer body 14 is 2 × 10 ^{−6 to} 6 × 10 ⁻⁶ [1 / ° C.]. It is necessary to consist of the following materials. Furthermore, it is desirable that the first member 11 and the second member 13 constituting the spacer body 14 have a low thermal conductivity. In the case of this example, the first member 11 and the second member 13 are made of ceramics.
[0018]
That is, since the thermal conductivity of ceramics or the like is 25 [W · m ⁻¹ · K ⁻¹ ], the thermal conductivity of the material constituting the spacer body 14 is 25 [W · m ⁻¹ · K ^−1]. It is desirable that In addition to ceramics, examples of materials that satisfy these conditions include amber (iron 64% nickel 36% alloy) and glass.
[0019]
FIG. 2 is an exploded perspective view showing the configuration of the spacer main body 14, and FIG. 3 is a longitudinal sectional view of the heat insulating spacer 10. As shown in FIGS. 2 and 3, the first member 11 has a generally cylindrical shape, and a sphere b that contacts the piezo stack 5 (see FIG. 1) and the operation portions 5 a and 3 a of the valve body 3 is vertically arranged. The recessed part 11a to hold | maintain is formed.
[0020]
The second member 13 has a substantially cylindrical shape formed with a through hole 12 that slidably holds the first member 11 in the center, and is fitted into the recess 4a (see FIG. 1) at the lower end thereof. The convex part 10b which forms is formed, and the recessed part 10b which inserts the said convex part 7a in the upper end part is formed. The concave portions 4a and 10b have the same shape, the convex portion 10a is formed slightly lower than the depth of the concave portion 4a, and the length l of the first member 11 is the height h (length) of the second member 13. ).
[0021]
13a is a flange formed at the lower end of the outer periphery of the second member 13, and 13b is a through hole for screwing. Also, the diameter D of the second member 13 shown in FIG. 3 is formed slightly smaller than the inner diameter of the heat radiating body 15, and the mounting portion between the heat radiating body 15 and the second member 13 is a flexible adhesive such as silicon. Install using.
[0022]
The heat radiator 15 is made of a material having excellent thermal conductivity such as aluminum, and is in close contact with the spacer body 14 (particularly the flange 13a of the second member 13) at the lower end portion 15b. Further, the cooling fins 15a provided in a plurality of stages on the outer periphery of the radiator 15 are configured to have a width of several millimeters so as to increase the heat dissipation effect by expanding the contact area with the surrounding air and eliminate unnecessary protrusions. ing.
[0023]
FIG. 4 is a view showing how heat is transmitted in the high temperature compatible valve 1. As shown in FIG. 4, the heat transmitted from the fluid to be controlled is transmitted from the lower valve body 3 side to the heat radiating plate 15. First, the temperature of the heat radiating plate 15 rises, and the heat radiating plate 15 expands due to the heat. Even if this occurs, the silicon adhesive is interposed in the contact portion between the spacer body 14 and the distortion is absorbed. That is, even if the heat dissipating body 15 expands to some extent due to heat, no distortion force is generated in the second member 13 due to this.
[0024]
In FIG. 4, as indicated by an arrow A, the heat transferred from the lower end side of the spacer body 14 to the second member 13 diffuses upward while forming a temperature gradient, and further moves to an arrow B while forming a temperature gradient. As shown, only the heat transmitted to the first member 11 and diffused into the information is transmitted to the piezo stack 5. On the other hand, most of the heat transmitted from the lower end side of the spacer body 14 to the second member 13 is transmitted to the heat radiating plate 8 as shown by an arrow C and released to the outside air. Further, the heat further transmitted through the second member 13 is transmitted from the upper end of the second member 13 to the spacer holder 7 as indicated by an arrow D, and is transmitted to the cover 6 via the spacer holder 7.
[0025]
Thus, even at a high temperature of heat by, for example, about 200 ° C. from the fluid in the lower end portion of the spacer body 14, at least 120 ° C. in the upper end portion of the spacer body 14 when the temperature gradient is formed by a spacer body 14 Can be reduced to: Further, as in the present example, by forming the cooling fins 15a in a plurality of stages in the vertical direction, even if the lowermost cooling fin 15a reaches a high temperature, for example, close to 200 ° C., the cooling fins 15a are directed upwards over the radiator 15 Since it is cooled by the cooling fins 15a of each part before it is transmitted, the heat of each part can be efficiently cooled at the respective height positions. Moreover, 100 degrees C or less can be maintained in the upper part of the actuator 1B.
[0026]
Further, the first member 11 and the second member 13 constituting the spacer main body 14 of this example are both made of ceramic and have the same thermal expansion coefficient (linear expansion coefficient due to heat) as that of the piezo stack 5. Therefore, the thermal expansion caused by the spacer main body 14 is the same as that of the piezo stack 5, so that the operation amount is not adversely affected, and the flow rate can be controlled even when a high-temperature fluid is controlled. The spacer body 14 preferably has a smaller coefficient of thermal expansion. Furthermore, the larger the temperature gradient formed by the spacer body 14 is, the better it is, so the smaller the thermal conductivity is, the smaller the spacer body 14 can be made. In addition to ceramic, amber, glass, or the like can be used as a material that satisfies these conditions.
[0027]
【The invention's effect】
The high-temperature compatible valve of the present invention can perform high-precision flow rate control using a piezo stack even for a high-temperature fluid.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view generally showing an example of a high temperature compatible valve of the present invention.
FIG. 2 is an exploded perspective view showing a spacer main body of the high-temperature compatible valve.
FIG. 3 is a longitudinal sectional view showing a configuration of a heat insulating spacer of the high temperature compatible valve.
FIG. 4 is a diagram for explaining the flow of heat in the high-temperature compatible valve.
FIG. 5 is a diagram illustrating a configuration of a conventional flow control valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... High temperature response valve, 1A ... Valve base | substrate, 1B ... Actuator, 2a, 2b ... Flow path, 3 ... Valve body, 3a ... Operation part, 5 ... Piezo stack, 10 ... Thermal insulation spacer, 11 ... 1st member, 12 ... Through hole, 13 ... second member, 14 ... spacer body, 15 ... heat radiator, 15a ... cooling fin, l, h ... length.

Claims (6)

  A valve base having a valve body that opens and closes a flow path of a fluid to be controlled, and an actuator having a piezo stack attached to the valve base and operating an operation portion of the valve body. A spacer body that transmits the operation of the piezo stack to the valve body and dissipates the heat transmitted from the valve body side, and the spacer body heats less than the thermal expansion coefficient of the piezo stack. A high temperature valve characterized by being made of a material having an expansion coefficient.   The spacer body has a rod-shaped first member that connects the operation portion of the piezo stack and the operation portion of the valve body, a through hole that slidably accommodates the first member, and an outer peripheral portion of the actuator and the valve base. 2. The high-temperature-compatible valve according to claim 1, comprising a second member having a predetermined length so as to be joined at a predetermined interval, wherein the length of the first member is the same as the length of the second member. The high-temperature-compatible valve according to claim 2, wherein the spacer body is made of a material having a thermal expansion coefficient of 2 x ^{10-6 to} 6 x ^10-6 [1 / ° C] or less.   The high temperature compatible valve according to claim 1, wherein the spacer body is made of ceramic.   The said spacer main body has a cylindrical heat radiator in the outer periphery which has the multistage cooling fin in the outer periphery which can cool the temperature of the said spacer main body with a temperature gradient in each position. High temperature compatible valve. A valve base including a valve body that opens and closes a flow path of a fluid to be controlled; and an actuator including a piezo stack that is attached to the valve base and operates an operation unit of the valve body, A first member located between the actuator and the valve base and transmitting the operation of the piezo stack to the valve body; and a second member having a hole for slidably receiving the first member; One member and the second member are made of a material having a thermal expansion coefficient equal to or lower than that of the piezo stack.

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