JPH049944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ball valve equipped with a spherical valve body, which is attached to a fluid piping and used for opening and closing the piping or adjusting the flow rate through which it passes.

In recent years, automation of fluid equipment has become active, and as a result, demand for electrically driven automatic valves is increasing.
BACKGROUND ART As can be seen in medical equipment, kitchen equipment, and the like, efforts are being made to actively develop fluid equipment in particular to make them more compact. As a result, smaller, lighter weight, and lower cost automatic valves are required.

Conventionally, proportional control valves have been frequently used when controlling the temperature, liquid level, liquid volume, etc. of a controlled fluid with high accuracy, and electromagnetic valves when the required accuracy is low. However, proportional control valves are large and expensive. Large-diameter solenoid valves have to be pilot-type, resulting in large flow resistance, poor sealing performance against low-pressure fluid, and because the valve continues to be energized during operation, there are many failures such as burnout of the coil.

Therefore, automatic valves using ball valves with low flow resistance and good sealing performance have been attracting attention. However, since the main use of conventional electric ball valves was simply to open and close piping, the opening and closing speed was slow, around 10 seconds, and they could not be used as a substitute for proportional control valves or solenoid valves. It is necessary to increase the opening/closing speed from 1 second to 3 seconds.

The proportion of the electric actuator in the size, weight, and cost of an electric ball valve is extremely large compared to the ball valve, and considering that there is very little room for improvement in these aspects of the ball valve itself, it is important to consider that the electric actuator is small, lightweight, and low cost. In order to obtain an electric ball valve that opens and closes at high speed and at low cost, the electric actuator must be improved. However, the reason why electric actuators are large, heavy, expensive, and have a low opening/closing speed is because the operating torque of the ball valve is large, so we ended up developing a ball valve with a small operating torque. run out.

The operating torque required to rotate the valve stem of a ball valve is due to the resistance between the valve stem and the packing disposed around it, and the resistance between the valve body and the valve seat. The present invention is directed to reducing the resistance between the valve body and the valve seat.

Furthermore, since automatic valves are frequently opened and closed, ball valves are required to have high durability. This has an elastic member placed on the back side of the valve seat that urges the valve seat toward the valve body.Even if the valve seat wears out, the contact between the valve seat and the valve body is maintained and the desired sealing function is maintained. A ball valve having a structure in which this type of valve seat is maintained is suitable, and the present invention also aims to improve a ball valve having such a valve seat structure.

Prior Art The structure of the valve seat portion of a conventional ball valve is shown in FIG. The valve casing D1 is made of metal such as cast iron, gunmetal, or stainless steel, and forms a valve chamber D7 and an inlet/outlet passage D2 communicating therewith, and a valve body D3 is disposed within the valve chamber D7. The valve body D3 is a spherical body with a through hole D4 (parallel to the paper), and the corner of the through hole D4, that is, the joint D5 with the outer surface is rounded. The valve shaft (not shown) passing through the valve casing D1 rotates around a rotation axis (perpendicular to the plane of the paper) passing through the spherical center D6.

At the connection between the valve chamber D7 and the inlet/outlet passage D2, coaxial holes D8 and D9 are formed on a wall D10 perpendicular to the hole D8 and D9.
to form a valve seat receiving space connected in an annular and stepped manner,
A valve seat D11 and an elastic member D12 are arranged.

The valve seat D11 is annularly formed of fluororesin, and has an inner diameter approximately equal to the inner diameter of the connecting hole D9 of the inlet/outlet passage D2, and an outer diameter approximately equal to the inner diameter of the connecting hole D8 of the valve chamber D7. The inner and outer ends are planes parallel to the connection vertical wall D10. The corner on the side of the valve body D3 is an approximately 45-degree slope, forming the valve seat surface D13 in contact with the outer surface of the valve body D3, and the diagonal corner is cut off to have a square cross section to connect the connection hole D8 and the vertical wall D10. An annular space having a rectangular cross section is formed at the corner formed by , and accommodates the elastic member D12. The elastic member D12 is made of synthetic rubber and formed into an annular shape, and is an O-ring with a circular cross section. The O-ring D12 is arranged in an annular space with a square cross section between the valve casing D1 and the valve seat D11 with its inner and outer circumferences and inner and outer ends crushed, and as a result, the compression reaction force pushes the valve seat D11 against the valve body D3. The valve casing D1 and the valve seat D11 are elastically biased, and the valve seat D11 is airtightly sealed.

FIG. 14 shows the operating torque characteristics when the ball valve is moved from the fully open position to the previous closing date. The horizontal axis shows the rotational position of the valve body, and the vertical axis shows the operating torque of the valve shaft. The vertical line at the left end indicates the fully open position, and the vertical line at the right end indicates the fully closed position. As shown in the figure, the operating torque characteristic curve E1 has two curves near the fully open position and near the fully closed position.
It has two peaks E2 and E3, indicating that the operating torque increases when the valve starts opening and just before the valve closes. Moreover, the mountain E3, which is just before the completion of valve closing, is larger.
Therefore, in order to reduce the operating torque of the ball valve, it is necessary to reduce the torque just before the valve closes, that is, the peak E3.

The mountain E2 is the result of the valve seat surface D13 of the valve seat D11 being pressed against and fitting into the outer surface of the valve body D3 when the valve seat D11 is fully opened. The arrow E3 is related to the deformation and displacement of the valve seat D11 when the valve body D3 is rotated. This will be explained by returning to FIG. 13. Since the valve seat D11 is biased toward the valve body by the elastic member D12, the portion that is not in contact with the outer surface of the valve body D3 is pushed toward the valve body side. The part of the valve seat D11 that has been raised in this way is connected to the opening end D5 of the through hole D4.
It must be rotated while being pushed back. This becomes noticeable just before the valve closes.

In the lower part of the valve seat D11 in FIG. 13, the valve seat surface D13' is deformed and displaced to the inside of the opening end D5 of the through hole D4 of the valve body D3, and the corner D14 of the outer peripheral surface is connected. It is strongly pressed against the inner circumferential surface of the hole D8. The closer the valve body D3 approaches the fully closed position, the more forcefully it will press the valve seat D11 downward in the drawing, and the frictional resistance of the corner D14 will become larger and larger, requiring a large force to push back the valve seat D11. do. Then, the valve seat surface D13' is scraped off at the opening end D5 of the through hole D4.

OBJECTS OF THE INVENTION The object of the present invention is to provide a ball valve with a highly durable valve seat structure in which the valve seat is biased toward the valve body by an elastic member, in which the valve seat is pushed out by the elastic member when the valve body rotates. The technical challenge is to reduce the frictional resistance when pushing back and reduce the operating torque just before closing, thereby creating a ball valve with low operating torque.

Solution to the Present Invention The technical means of the present invention taken to solve the above-mentioned technical operation is to provide a fluorine-containing fluorine-contained fluorine-container with a hole larger in diameter than the inlet/outlet passage hole at the end of the valve chamber that connects with the inlet/outlet passage. A valve seat guide member made of resin is disposed, and the outer circumferential wall of the valve seat made of fluororesin is slidably fitted into a hole of the valve seat guide member.

The operation of the above technical means will be explained. In the fully open position, the entire circumference of the valve seat surface is in contact with the outer surface of the opening edge of the through hole of the valve body. When the valve body is rotated toward the fully closed position, the valve seat surface comes off the outer surface of the valve body and is located in the through hole at the front of the rotation of the valve body, and is pushed into the through hole by the elastic means, Then, the valve seat surface that has been pushed out is pushed back by the outer spherical surface of the valve body.

During this deformation during opening and closing of the valve, the outer peripheral wall of the valve seat made of fluororesin, which has a small coefficient of friction, comes into contact with the inner wall of the hole in the valve seat guide member, which is also made of fluororesin, which has a small coefficient of friction, and slides. Crab slips. Therefore, once the valve seat is pushed out, it is pushed back lightly by the valve body, so
The operating torque just before the completion of valve closing is significantly reduced.

Effects of the Invention If the valve seat is fixed to the valve casing without using an elastic member or a stopper is provided on the valve body side of the valve seat, it is possible to prevent the valve seat from being pushed out toward the valve body. As the valve seat surface wears, the pressure contact force between the valve body and the valve seat decreases, and the sealing function deteriorates and is lost, and cannot be recovered, so it cannot withstand long-term use. With the valve seat of the present invention, even if the valve seat wears out, the valve seat can be displaced toward the valve body by being pushed by the fluid pressure acting on the elastic member and the back of the valve seat, so the desired seal performance will continue for a long time. do.

Since the operating torque just before the completion of valve closing is significantly reduced as described above, the maximum value of the operating torque is reduced, and therefore the required output of the electric actuator based on the maximum value is significantly reduced. For this reason, a small, lightweight, low-cost electric ball valve that opens and closes at high speed can be obtained. As the valve seat guide member made of fluororesin is used, the area of the elastic member in contact with the fluororesin increases. Therefore, especially for the elastic member made of synthetic rubber, the wear is less than when it comes into contact with the metal wall surface of the valve casing, and the sealing performance is improved.

Example An example showing a specific example of the above technical means will be described.

Embodiment 1 (See FIGS. 1 to 4) An electric valve using a ball valve according to the present invention will be described.

The valve casing of the ball valve 101 is the main body 102
and two end members 103 that are identical to each other.

The main body 102 roughly has the shape of a rectangular prism with a horizontal hole, and a disc-shaped electric arcuator 104 is mounted on the top.
It has an integral mounting base 105. The horizontal hole is valve chamber 10
6, and a valve shaft hole 107 and a support shaft hole 108 are coaxially bored perpendicularly to this horizontal hole.

A valve body 110 having a through hole 109 formed in a spherical body is installed in the valve chamber 106, and a valve stem 111 is inserted through the valve body 110 from the valve stem hole 107. The valve shaft 111 has a generally cylindrical shape, the lower part of which has a smaller diameter than the upper part, and forms a supporting shaft. The central part is a single-letter key with both sides cut off in parallel, and is fitted into a parallel groove formed at the top of the valve body 110. The lower part of the valve shaft 111, that is, the support shaft is
It passes through the valve body 110 from the parallel groove through the spherical center, and the tip part fits into the spindle hole 108. A sleeve-shaped bearing 1 is provided between the casing body 102 and the valve shaft 111.
12, two O-ring packings 113 made of synthetic rubber, and a sleeve-shaped bearing 11 between the support shaft
4 to intervene. Therefore, when the valve shaft 111 is turned from the outside, the valve body 110 rotates around the rotation axis passing through the spherical center.

Both end surfaces of the valve casing body 102 are valve chambers 106.
It is a plane perpendicular to the horizontal hole forming the hole, and the opening edge is formed into a lower annular plane. A cylindrical valve seat guide member 116 made of fluororesin and having an outer flange 115 that is slightly thicker than the width of the annular step is fitted and attached to this annular step. And the valve seat guide member 11
6, a ring-shaped valve seat 117 made of fluororesin and an O-ring packing 118 made of synthetic rubber are fitted, and the end member 103 is attached from the outside.

The inner diameter of the valve seat 117 and the inner diameter of the hole at the valve chamber side end of the inlet/outlet passage opened in the end member 103 are the same as those of the valve body 110.
The inner diameter of the through hole 109 is approximately the same as the inner diameter of the through hole 109. The end member 103 entrance/exit passage is provided with a thread for connecting piping. The outer flange has a rectangular shape that is approximately the same as the outer diameter of the main body 102, and is fixed to the main body 102 with bolts (not shown) through holes (not shown) drilled in the four corners. At this time, the outer flange 115 of the valve seat guide member 116 is sandwiched between the main body 102 and the end member 103 to airtightly seal the area and fix the valve seat guide member 116 there. At the same time, the O-ring packing 118 made of synthetic resin is compressed by a predetermined amount, and its elastic repulsion forces the valve seat 117 toward the valve body 110.
is energized by

Details of the valve seat portion will be explained with reference to FIG. 4. The inner peripheral wall surface of the valve seat guide member 116 made of fluororesin is finished into a perfect cylindrical surface.

The inner and outer end surfaces of the annular valve seat 117 made of fluororesin are perpendicular to the horizontal hole of the valve chamber 106, that is, parallel to the flange surface of the end member 103. Both the inner and outer peripheral wall surfaces are cylindrical surfaces. The center part of the inner corner protrudes from both sides thereof, and its annular surface, that is, the valve seat surface 119, is closer to the valve body 11.
It is a tapered surface of approximately 45 degrees parallel to the tangent of the contact outer surface of 0. The outer side of the valve seat surface 119 is recessed stepwise in the radial direction, so that even if the valve seat surface 119 wears, the contact area with the outer surface of the valve body 110 does not increase, and the pressure contact force per unit area is reduced. It is prevented. The inside of the valve seat surface 119 is continuously connected to the valve seat surface by a tapered surface having a smaller angle of expansion than the valve seat surface. This valve body guide surface 121 is such that even if the valve seat is deformed and displaced toward the valve body side, the open end 120 of the through hole 109 of the valve body 110 is not the inner surrounding surface of the valve seat, and the valve body guide surface 121
21 and then smoothly guided by the valve seat surface 119 that continues therefrom.

The outer corner of the valve seat 117 is an angle formed by cutting off the radial plane of the valve seat and a cylindrical surface coaxial with the valve seat, and forming the flange surface of the end member 103 and the inner circumferential surface of the valve seat guide member 116. An annular space having a rectangular cross section is formed between them, and an O-ring packing 118 made of synthetic rubber is placed therein. The chopstick member 103 is attached to the main body 10
2, this O-ring packing 118 is compressed by a predetermined amount from the inner and outer peripheries and both ends in the annular space having a rectangular cross section. As a result, the O-ring packing 118 urges the valve seat 117 against the valve body 110 by elastic repulsive force, and also provides an airtight sealing effect at the contact area between the valve seat 117 and the valve seat guide member 116. I do. Fluid pressure acts on the back surface of the valve seat 117. When the pressure of the fluid is low, the valve seat 117 mainly receives the biasing force from the O-ring packing 118, but when the pressure becomes high, the O-ring packing 118 pushes against the flange surface of the end member 103 as shown by the dashed line. The pressure-receiving area of the back surface of the valve seat 117 increases, and is pressed more and more strongly against the valve body in proportion to the fluid pressure.
This improves the sealing function between the valve body 110 and the valve body 110.

The outer corner 122 of the outer peripheral wall surface of the valve seat 122 is cut off into a tapered surface. As a result, when the valve seat 117 is deformed and displaced, if it had not been cut off, stress would have been concentrated and this corner would have been strongly pushed against the inner circumferential surface of the valve seat guide member 116, which would have caused frictional resistance. Reduced.

Returning to FIGS. 1 to 3, the electric actuator will be explained. A synchronous electric motor 131 and a speed reducer 132 are fixed to a circular lower box 130. Second
Reference number 133 in the figure is the electric motor 131 and the reducer 13
2 shows the screw holes for the mounting bolts (not shown).

Although the synchronous motor 131 rotates at a lower speed than the induction motor, it can obtain a large output torque. For this reason, the reduction gear 132 only needs to have a small reduction ratio, resulting in a small size and low cost.
Moreover, one-way joint (one-way clutch)
Even if you connect the output shaft of the reducer directly to the valve shaft of the ball valve as shown below without using the Even if the body becomes unable to rotate and the output shaft is restrained, the gears of the reducer will not be damaged. The overall structure of the electric actuator can be simplified and downsized.

The output shaft 134 passes through the center of the lower box 130 and projects downward. An O-ring packing 135 made of synthetic rubber provides an airtight seal between the lower box 130 and the lower box 130. A one-letter key cut parallel to both sides of the lower end of the output shaft 134 is fitted into a one-letter groove at the upper end of the valve shaft 111. The outer periphery of the fitting portion is surrounded by a bearing sleeve 112. Further, a manual operation lever 136 in the form of a strip having a thickness of several millimeters is interposed between the output shaft 134 and the valve shaft 111. Lever 1
A rectangular hole is drilled at the inner end of 36, and the single character key of the output shaft 134 is inserted into this hole, so the handle 1 covered with vinyl chloride at the outer end
36 and turn the lever 136, the output shaft 13
4, the valve shaft 111 rotates. Since the lever 136 reciprocates in a narrow groove and only the handle 136 protrudes outside the casing,
There is no risk of injury to hands or fingers.

The lower box 130 of the electric actuator 104 is fixed to the mounting base 105 of the ball valve 101 with a bolt 139 via a washer 138. The thickness of the washer 138 is made slightly larger than that of the lever 136, and the horizontal rotation of the lever 136 is guided by the lower end wall of the lower box 130 and the upper end wall of the mounting base 105. In addition, a pair of washers 139
also serves as a stopper for the lever 137, as shown by the two-dot chain line in FIG. 2 showing the other stop position of the lever 137. Since the lever 136 reciprocates together with the valve shaft 111, the position of the handle 137 indicates the open/close position of the ball valve 101.

A limit switch LS has a cam 140 attached to the output shaft 134 and arranged in two layers around it.
1. Drive LS2. Each limit switch LS
1. LS2 turns ON when the roller is on the cylindrical peripheral wall of the cam 140, and turns OFF when it falls into the groove provided on the cylindrical peripheral wall.

Control circuit components for the motor 131, such as a relay 141 and a capacitor 142, are installed in the space around the output shaft 134. Reference number 143 is a connector, 14
4 is a lead-in cable for power lines and signal lines. The cable 144 is connected to the gasket 14 by the bush 146.
5 to the lower box 130 in an airtight manner. An upper box 147 is attached to the lower box 130 covering the above actuator parts and fixed with screws 149. At this time, a gasket 148 made of synthetic rubber is interposed to airtightly seal the space between the upper box 147 and the lower box 130.

A control circuit for electric motor 131 will be explained with reference to FIG. A drive coil X of a control switch CS relay (corresponding to 141 in FIG. 1) is connected in series to the AC power source 150. The control switch CS is opened and closed manually or by a command signal from a sensor, and when it is ON, the drive coil X is excited and when it is OFF.
It is demagnetized when

Two types of coils 1 of synchronous electric motor 131
Limit switches LS1 and LS2 are connected between 51 and 152 via a phase advance capacitor C (corresponding to 142 in Fig. 1) with capacitor C in between, and a relay is connected to each limit switch LS1 and LS2. Relay terminals Xa and Xb operated by drive coil X
Connect in series. Xa is the so-called a terminal, Xb is b
When the control switch CS is turned ON, the drive coil X is excited and the terminal Xa is closed, and the limit switch LS2 is connected to the AC power supply 150.
When the control switch CS is turned OFF, the drive coil X is demagnetized, the terminal Xb is closed, and the limit switch LS1 is connected to the AC power supply 150.

As already explained, if limit switch LS1 is OFF at the fully open position, limit switch LS2 will be OFF at the fully open position, and both limit switches will be ON at intermediate positions. Then, connect the limit switch across capacitor C.
When the LS1 side is connected to the power supply 150 and when the limit switch LS2 side is connected to the power supply 150, the coils 151 and 1 of the motor 131 are
52 is reversed, and the motor 131
The left and right rotation direction of is determined.

Embodiment 2 (See Figure 5) This is an example in which the embodiment in Figure 4 is partially modified.
Corresponding parts will be given the same reference numerals and their explanation will be omitted.

The inner circumferential surface of the valve seat guide member 116 is not a straight cylindrical surface, but the cylindrical surface on the O-ring packing side is lower than the valve seat side at the boundary between the valve seat 117 and the O-ring packing 118. Make it slightly larger and connect the large and small cylindrical surfaces continuously with a tapered surface at a small angle. In this way, it is also possible to avoid concentration of stress on the outer peripheral angle of the valve seat when the valve seat 117 is deformed.

Embodiment 3 (See FIG. 6) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

The outer corner of the outer circumference of the valve seat 117 is cut off obliquely (reference number 601), an annular space with a triangular cross section is formed between the end member 103 and the valve seat guide member 116, and the O-ring packing 118 is attached. This is what was placed. The elastic repulsive force of the O-ring packing 118 acts not in the axial direction of the valve seat 117, but rather in the diagonally diagonal direction of the valve seat surface 119.
19 comes into better contact with the outer surface of the valve body, resulting in a good sealing effect. O-ring packing 1
18 is deformed as shown by the two-dot chain line when it is strongly subjected to fluid pressure, and the pressure receiving area on the back surface of the valve seat 117 is expanded, so that it can receive the fluid pressure more strongly.

Embodiment 4 (See FIG. 7) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

The entire outer periphery of the valve seat 117 is formed into a round barrel shape (reference number 701). If you do it like this,
When the valve seat 117 is deformed, stress concentration can be avoided at both the inner and outer corners of the outer periphery of the valve seat.

Embodiment 5 (See FIG. 8) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

The outer periphery of the valve seat 117 of the valve seat guide member 116 has a contact portion 801 that projects inward in a round annular shape. In this way, stress concentration can also be avoided at both the inner and outer corners of the outer periphery of the valve seat when the valve seat 117 is deformed.

Embodiment 6 (See FIG. 9) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

An annular groove with a square cross section is formed on the outer periphery of the valve seat 117 near the back surface, and an O-ring packing 118 is fitted into the groove. At that time, the width of the groove is made smaller than the O-ring packing 118, so that when the valve seat is fitted, the lip 901 on the back side of the valve seat is aligned with the end member 103.
Let it bulge out to the side. In this way, the O-ring packing 118 made of synthetic rubber is surrounded entirely by fluororesin, making it less susceptible to deterioration.

Embodiment 7 (See FIG. 10) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

The outer periphery of the valve seat 117 remains a straight cylindrical surface. However, the outer periphery of the valve seat guide member 116 is cut into a groove (reference number A01) having a rectangular cross section to make the valve seat guide member 116 more flexible as shown by the two-dot chain line. When the valve seat 117 is not deformed, the entire outer peripheral surface of the valve seat is in contact with the inner peripheral surface of the valve seat guide member, so that the valve seat is reliably held in a predetermined position. Further, since there is no gap between the contact portion between the valve seat 117 and the valve seat guide member 117, damage to the O-ring packing 118 is reduced.

Embodiment 8 (See FIG. 11) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

A corner of the outer edge of the outer periphery of the valve seat 117 is cut off squarely, and a groove is cut in the axial direction of the valve seat from the cut off part, leaving a cylindrical lip B01. and,
Two thin rings B02 made of fluororesin are interposed between the O-ring packing 118 and the O-ring packing 118. By doing this, when the valve seat 117 is deformed and displaced,
Since the lip B01 is bent as shown by the two-dot chain line, stress concentration can be avoided. The O-ring packing 118 is prevented from fitting into the inner groove of the lip by the thin plate ring B02.

Embodiment 9 (See FIG. 12) This is also an example in which the embodiment shown in FIG. 4 is partially modified, so corresponding parts are given the same reference numerals and a description thereof will be omitted.

The valve seat 117 is made of fluororesin and has an O-ring shape. However, there is a synthetic rubber O-ring C01 inside.
envelops. This valve seat 117 is the valve body 110
It is arranged in a compressed state in the annular space between the end member 103 and the valve seat guide member 116. Therefore, the elastic repulsive force of the O-ring C01 causes the valve seat 11 to
The surface of 7 is biased against the valve body 110. Moreover, since the valve seat 117 is O-ring shaped, it smoothly responds to deformation of the valve seat, and since the synthetic rubber of the O-ring C01 is not exposed to fluid at all, it has excellent chemical resistance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an electric valve using a ball valve according to the present invention, Fig. 2 is a plan view of the lower box of the electric actuator, Fig. 3 is a control circuit diagram of the electric motor, and Fig. 4 is the ball valve of Fig. 1. 5 to 12 are cross-sectional views of the valve seat portion of the valve according to other embodiments, similar to FIG. 4, and FIG. 13 is a conventional ball valve valve seat and valve body. FIG. 14 is a graph showing the operating torque characteristics of a conventional ball valve. 101: Ball valve, 102: Casing body,
103: end member, 104: electric actuator,
109: Through hole, 110: Valve body, 116: Valve seat guide member made of fluororesin, 117: Valve seat made of fluororesin, 118: Elastic member (O-ring packing), C01: Elastic member.

Claims (1)

[Claims] 1. In a valve seat structure in which the valve seat is biased toward the valve body by an elastic member, a valve made of fluororesin has a hole larger in diameter than the inlet/outlet passage hole at the end that connects to the inlet/outlet passage of the valve chamber. A ball valve in which a valve seat guide member is arranged, and an outer circumferential wall of a fluororesin valve seat is slidably fitted into a hole in the valve seat guide member.