JP4084861B2 - Control valve with heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a control valve (usually called a “butterfly valve”) that rotates a valve body provided in a circular fluid passage of a valve body (base) to open and close the fluid passage.
[0002]
[Prior art]
FIG. 6 shows such a conventional control valve.
The control valve 60 includes a valve main body (base) 64 having a circular fluid passage 63 and a disc-like valve body 70 that fits the fluid passage 63. The valve body 70 is fixed to a valve shaft 62 that penetrates the valve main body 64, and the valve shaft 62 is connected to a motor 66. The valve body 70 is rotated by the motor, and the circular fluid passage 63 is opened and closed.
In the conventional control valve 60, a rubber O-ring is provided on the outer periphery of the valve body 70 to emphasize the shut-off function in the closed state, and the operability and control function are emphasized without providing the O-ring. There are some types.
[0003]
[Problems to be solved by the invention]
However, in the control valve that places importance on the shut-off function in the closed state, when the valve body 70 is closed, the O-ring provided on the outer periphery of the valve body 70 slides with respect to the fluid passage 63, so that friction powder is generated. Then, there is a problem of mixing in the liquid. On the other hand, in a control valve not provided with an O-ring, a slight gap is provided between the fluid passage 63 and the valve body 70 in advance so that the inner periphery of the valve body 64 and the valve body 70 do not come into contact with each other. There are also problems that sometimes fluid easily leaks and it is difficult to control a minute flow rate.
[0004]
[Means for Solving the Problems]
The present invention provides a control valve that opens and closes a circular fluid passage provided in a valve body with a valve body rotated by a valve shaft.
Comprising a heater in said valve body, which valve body have a valve plate made of Teflon (registered trademark), is expanded by heating of the heater,
The above problem has been solved by a control valve that adjusts the clearance of the fluid passage by adjusting the degree of thermal expansion of the valve body by the voltage applied to the heater .
In a typical embodiment of the present invention, the heater is provided inside the valve shaft, and the valve body sandwiches the valve plate made of Teflon (registered trademark) , the valve shaft and the valve plate. It consists of a metal valve plate fixing plate.
If the valve body has a tapered surface or a curved surface that converges in the fluid flow direction in a state where the fluid passage is closed, the effective area of the fluid passage greatly changes due to the rotation of the valve body. It is possible to prevent and control the flow rate more finely.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a front view showing a main part of a control valve 10 of the present invention in cross section.
The control valve 10 includes a valve body (base) 14 including a fluid passage 13 having a circular cross-sectional shape, and a substantially disc-shaped valve body 20 that fits the fluid passage 13. The control valve 10 is made of a metal such as stainless steel (SUS) as a whole except for a part of the valve body 20.
[0006]
The valve body 20 is fixed to a valve shaft 12 that is pivotally supported by the valve body 14, and the valve shaft 12 is connected to a motor 16. When the valve body 20 is rotated by the operation of the motor 16, the fluid passage 13 having a circular cross section is opened and closed.
The control valve 10 includes a fluid passage even when the valve is fully closed so that the turning function of the valve body 20 is not hindered by sliding friction between the fluid passage 13 and the valve body 20 when the valve body 20 is rotated. A minute gap is formed between the valve body 13 and the valve body 20.
[0007]
FIG. 2 is a perspective view of the valve shaft 12 and the valve body 20 separated from each other.
A disc-shaped valve plate 20a having a diameter suitable for the fluid passage 13 of the valve body 14 includes a notch 20e extending in the diametrical direction for receiving the valve shaft 12, and a valve plate sandwiching both side surfaces of the valve plate 20a. Circular recesses 20f and 20g for receiving the fixing plates 20b and 20c are formed.
Like the valve plate 20a, the one valve plate fixing plate 20b is provided with a notch 20h extending in the radial direction for receiving the valve shaft 12. However, the other valve plate fixing plate 20c has such a notch. There are no notches.
[0008]
3 is a cross-sectional view taken along line 3-3 of FIG.
The valve plate 20a is fixed by four fixing screws 20d in a state where the valve shaft 12 is received in the notch 20e, and the valve plate fixing plate 20b and the valve plate fixing plate 20c are received in the side recesses 20f and 20g, respectively. Yes.
In the valve body 20, the valve plate 20a is made of Teflon (registered trademark) , and the others are made of metal such as stainless steel. The material of the configuration other than the valve plate 20a is not limited to stainless steel, but stainless steel is lightweight and corrosion resistant, so when controlling the flow rate of corrosive gas, Is preferred.
[0009]
FIG. 4 is a longitudinal sectional view of the valve shaft 12.
A heater 30 is provided in the hollow interior of the cylindrical valve shaft 12 via a lead wire 31. As the heater 30, an appropriate electric heater such as a nichrome wire type or a tungsten wire type can be used.
[0010]
Since Teflon (registered trademark) has a coefficient of thermal expansion approximately 10 times that of stainless steel, when the heater 30 inside the valve shaft 12 is energized, the valve shaft 12, the valve plate 20a, and the valve plate fixing plate 20b. , 20c is heated, but the valve plate 20a made of Teflon (registered trademark) significantly expands in the radial direction.
The valve plate 20 a expanded in the radial direction reduces the gap between the fluid passage 13 and the valve body 20.
[0011]
As an actual usage,
1. A method of controlling the flow rate of the fluid by rotating the valve body 20 in a state where a predetermined voltage is applied to the heater 30 to generate heat and the gap between the fluid passage 13 and the valve plate 20a is reduced in advance;
2. Normally, the heater 30 is not used, and the heater 30 is energized only when the valve body 20 is in the closed state, and the gap between the fluid passage 13 and the valve plate 20a is finely adjusted by the strength of the voltage so that the flow rate is fine. There is a method of performing control.
In addition to the above method, it goes without saying that the heater 30 can be used in the same manner as before without energizing the heater 30 at all.
[0012]
FIG. 5 is an example of a diagram showing the relationship between the temperature of the valve plate 20a and the fluid outflow amount in the control valve 10 of the present invention when the valve opening is constant.
[0013]
The shape of the valve body 20 of the control valve 10 of the present invention is formed so that the cross section thereof is a curved surface converging in the fluid flow direction, but is not limited to this shape. As disclosed in Japanese Patent Laid-Open No. 7-317919, a tapered surface may be employed instead of a curved surface.
When the valve body 20 is formed to have a tapered surface or a curved surface, the effective area of the flow path changes greatly even if the valve body 20 rotates a little in a range where the rotation angle of the valve body 20 with respect to the valve body 14 is relatively small. It is prevented.
[0014]
In addition, although the thing which incorporated the heater 30 in the valve shaft 12 was shown as embodiment of this invention, as a place which provides the heater 30, it is not limited in the valve shaft. It can also be provided on the valve plate itself.
[0015]
【The invention's effect】
According to the configuration of the present invention, since the valve body can be heated by the heater, the valve body is expanded in the radial direction, and the gap provided in advance between the fluid passage and the valve body is reduced in the fully closed state. Thus, it is possible to enhance the shut-off function and to control a minute flow rate.
In addition, the degree of thermal expansion of the valve element can be adjusted by the voltage applied to the heater, and the gap between the flow paths can be adjusted more finely. It is possible to control the flow rate.
[0016]
Furthermore, since the valve body is heated by the heater, it is possible to prevent the contaminants from adhering to the valve body and to prevent the gas from being liquefied.
Further, by forming a tapered surface or a curved surface on the valve body, it is possible to prevent the effective area of the fluid passage from changing greatly due to the rotation of the valve body, and to control the flow rate more finely.
[Brief description of the drawings]
FIG. 1 is a front view showing a cross section of a main part of a control valve of the present invention.
FIG. 2 is a perspective view in which a valve shaft and a valve body are separated.
3 is a cross-sectional view taken along line 3-3 in FIG.
FIG. 4 is a longitudinal sectional view of a valve shaft. FIG. 5 is a diagram showing the relationship between the temperature of a valve body and the amount of fluid flowing out.
FIG. 6 is a front sectional view of a conventional control valve.
[Explanation of symbols]
10: Control valve 12: Valve shaft 13: Fluid passage 14: Valve body 20: Valve body 20a: Valve plate 20b: Valve plate fixing plate 20c: Valve plate fixing plate 30: Heater

Claims (3)

In a control valve that opens and closes a circular fluid passage provided in a valve body with a valve body rotating by a valve shaft,
Comprising a heater in said valve body, which valve body have a valve plate made of Teflon (registered trademark), is expanded by heating of the heater,
By adjusting the degree of thermal expansion of the valve body by the voltage applied to the heater, the gap of the fluid passage is adjusted ,
Control valve. The heater is provided inside the valve shaft, and the valve body includes a valve plate made of Teflon (registered trademark) and a pair of metal valve plate fixing plates sandwiching the valve shaft and the valve plate. The control valve of claim 1.   The control valve according to claim 1 or 2, wherein the valve body has a tapered surface or a curved surface that converges in a fluid flow direction in a state where the fluid passage is closed.

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