JP2024095863A - Ball seats and ball valves - Google Patents

Abstract

To provide a technology which can inhibit shifting and deformation of a seat link even if a ball seat is used in a cryogenic fluid and achieves more stable sealability with the ball seat regardless of a use environment.SOLUTION: A ball seat (1) comprises: an annular seat ring (10); an outer ring (20) at the outer periphery side; and an inner ring (30) at the inner periphery side. A radial cross section of the inner ring (30) is a shape which protrudes to the radial inner side and in which a width of the inner ring (30) gradually reduces.SELECTED DRAWING: Figure 3

Description

The present invention relates to a ball seat and a ball valve.

Ball valves are used in a variety of technical fields for controlling fluid flow, as they are applied to control the flow of large volumes of fluid. In ball valves, a ball seat is used to seal between the fluid flow path and the ball valve body. The ball seat has a seat ring that contacts the ball valve body, but may be accompanied by an additional ring in the circumferential direction for reinforcement. A known ball seat of this type is one that is composed of a seat ring and an outer ring on its outer periphery (see, for example, Patent Document 1). Another known ball seat is one that is composed of a seat ring, an outer ring on its outer periphery, and a backup ring on its inner periphery (see, for example, Patent Document 2).

International Publication No. 2021/172457 Japanese Utility Model Publication No. 7-49146

The seat ring is usually made of a deformable material such as resin. The outer ring and inner ring are made of a material with higher rigidity such as metal to protect the seat ring. Therefore, the seat ring is more easily deformed than other rings, and is more likely to expand and contract due to heat, for example. When a ball valve is used for cryogenic fluids such as liquefied hydrogen, the ball seat is exposed to the cryogenic environment, and the seat ring deforms, particularly shrinking toward the inner diameter.

Therefore, in the above-mentioned conventional technology, when a ball seat is used with a cryogenic fluid, the seat ring shrinks in the radial direction, causing the position of the part of the seat ring that abuts against the ball valve body or the seat retainer to shift, or the backup ring to fall off due to deformation of the seat ring, which can result in the desired sealing performance not being achieved. As such, the conventional technology leaves room for further study in terms of enabling the ball seat to achieve the desired sealing performance regardless of the usage environment.

One aspect of the present invention aims to provide a technology that can suppress misalignment and deformation of the seat ring even when the ball seat is used with cryogenic fluids, and that can provide stable sealing performance with the ball seat regardless of the usage environment.

In order to solve the above problems, the ball seat according to one aspect of the present invention is an annular ball seat that is sandwiched between a ball valve body and a seat retainer in a ball valve to seal the space between the two, and has an annular seat ring, an annular outer ring that contacts the seat ring on the outer periphery side of the seat ring, and an annular inner ring that contacts the seat ring on the inner periphery side of the seat ring, and the cross-sectional shape of the inner ring in the radial direction is a shape that is convex toward the inside in the radial direction, and the width of the inner ring gradually increases from the inside in the radial direction toward the seat ring.

In order to solve the above problems, a ball valve according to one aspect of the present invention has a ball valve body, a seat retainer, and the above-mentioned annular ball seat that is sandwiched between them to seal the space between them.

According to one aspect of the present invention, even when the ball seat is used with cryogenic fluids, it is possible to suppress displacement and deformation of the seat ring, and it is possible to achieve a more stable sealing performance than the ball seat regardless of the usage environment.

1 is a diagram showing a ball seat according to a first embodiment of the present invention, as viewed from one side in the axial direction. FIG. 3 is a diagram showing a ball seat according to the first embodiment of the present invention, as viewed from the other axial side. FIG. 1 is a diagram showing a schematic radial cross section of a ball seat according to a first embodiment of the present invention; FIG. 4A to 4C are diagrams for explaining the relationship between tapered surfaces in the ball seat according to the first embodiment of the present invention. 1 is a cross-sectional view showing a schematic configuration of a ball valve according to a first embodiment of the present invention. FIG. 6 is an enlarged schematic cross-sectional view of a portion A in FIG. 5, viewed obliquely in a radial direction. FIG. 6 is an enlarged schematic front view of a radial cross section of part A in FIG. 5 . FIG. 1 is a diagram for explaining a state in which a seat ring is burned in the ball valve according to the first embodiment of the present invention. FIG.

[Ball seat]
An embodiment of the present invention will be described in detail below. FIG. 1 is a diagram showing a ball seat according to the first embodiment of the present invention, as viewed from one side in the axial direction, and FIG. 2 is a diagram showing a ball seat according to the first embodiment of the present invention, as viewed from the other side in the axial direction. FIG. 3 is a diagram showing a cross section in the radial direction of the ball seat according to the first embodiment of the present invention. The ball seat 1 has a seat ring 10, an outer ring 20, and an inner ring 30. The Z direction in the figure is the radial direction of the ball seat 1, and the Y direction is the axial direction of the ball seat 1. An acute angle among the angles formed by an arbitrary virtual line L1 in the radial direction of the ball seat 1 and a straight line along a certain surface is also called the inclination angle of the surface. Furthermore, the "cross section" of the ball seat means a cross section in the radial direction unless otherwise specified.

[Seat ring]
The seat ring 10 is a ring made of, for example, graphite or resin such as polychlorotrifluoroethylene (PCTFE) and ultra-high molecular weight polyethylene (UHMW-PE). The seat ring 10 has a substantially rectangular cross-sectional shape. The seat ring 10 has a first seat tapered surface 11 on one side in the axial direction and a second seat tapered surface 12 on the other side in the axial direction. The first seat tapered surface 11 is a surface designed to abut against a ball valve body when the ball seat 1 is applied to a ball valve. The second seat tapered surface 12 is a surface designed to abut against a seat retainer when the ball seat 1 is applied to a ball valve. The inclination angle of the first seat tapered surface 11 is larger than the inclination angle of the second seat tapered surface 12.

The seat ring 10 has an outer cutout 13 on one side, on the radially outer side, and an inner cutout 14 on the other side, on the radially inner side. The outer cutout 13 is a portion cut out in a radially elongated rectangular shape. The inner cutout 145 is a portion cut out in an axially elongated rectangular shape.

The seat ring 10 also has a groove 15 on its outer circumferential surface. The groove 15 has a rectangular cross-sectional shape that is elongated in the radial direction.

[Outer ring]
The outer ring 20 is an annular member that contacts the seat ring 10 on the outer circumferential side of the seat ring 10. The outer ring 20 is made of a metal such as stainless steel. The outer ring 20 has a generally rectangular cross-sectional shape that is elongated in the axial direction compared to the inner ring.

The outer ring 20 has an outer protrusion 21 that protrudes radially inward on one side of the cross section. The outer protrusion 21 is a generally rectangular part that is elongated in the axial direction.

The outer ring 20 has a first outer tapered surface 22 on the inside of one axial side, and a second outer tapered surface 23 on the inside of the other axial side. The inclination angle of the first outer tapered surface 22 is greater than the inclination angle of the second outer tapered surface 23.

The outer ring 20 also has a groove 24 on its inner circumferential surface. The groove 24 faces the groove 15 of the seat ring and has a rectangular cross-sectional shape that is elongated in the axial direction. In other words, the groove 24 is shallower than the groove 15.

In addition, the corners of the outer peripheral surface and both side surfaces of the outer ring 20 are chamfered.

[Inner ring]
The inner ring 30 is an annular member that contacts the seat ring 10 on the inner circumferential side of the seat ring 10. The inner ring 30 is made of a metal such as stainless steel. The inner ring 30 has a cross-sectional shape that is convex toward the inside in the radial direction, and the width of the inner ring 30 gradually increases from the inside in the radial direction toward the seat ring 10. For example, the inner ring 30 has a substantially triangular cross-sectional shape that increases toward the outside in the radial direction.

The inner ring 30 has a first inner tapered surface 31 on one axial side and a second inner tapered surface 32 on the other axial side. The distance between the two tapered surfaces in the axial direction gradually increases radially outward. The inclination angle of the first inner tapered surface 31 is larger than the inclination angle of the second inner tapered surface 32.

The inner ring 30 also has an inner protrusion 33 that protrudes radially outward on the other side of the cross section. The inner protrusion 33 has a rectangular cross-sectional shape.

[Engagement between rings]
The groove 15 of the seat ring 10 faces the groove 24 of the outer ring 20, and a C-ring 40 is disposed across both grooves. The C-ring 40 is made of, for example, metal. The C-ring 40 is a substantially annular member with a portion missing in the circumferential direction, and has a rectangular cross-sectional shape. The seat ring 10 and the outer ring 20 are fixed to each other by fitting the C-ring 40 into the grooves 15, 24 provided on the opposing surfaces of the two. The cutout portion of the C-ring 40 is slightly expanded, and when housed in the grooves 15, 24, the entire ring is biased toward the outside in the radial direction. Therefore, the C-ring 40 is biased toward the outer ring 20, and its outer peripheral surface comes into contact with the bottom surface of the groove 24, and a gap may be formed between the inner peripheral surface of the C-ring 40 and the bottom surface of the groove 15. The inner ring 30 and the seat ring 10 are not connected by such a C-ring, but the inner ring 30 is firmly fitted into the seat ring 10. Therefore, the two will not easily become detached or misaligned.

The outer protrusion 21 of the outer ring 20 engages with the outer cutout 13 of the seat ring 10. The inner protrusion 33 of the inner ring 30 engages with the inner cutout 14 of the seat ring. In this way, the outer ring 20 engages with the seat ring 10 on one side in the axial direction on the outer circumferential side, and the inner ring 30 engages with the seat ring 10 on the other side in the axial direction on the inner circumferential side.

[Positional relationship of seat ring to tapered surface]
When the ball seat 1 is applied to a ball valve that handles flammable fluid, if a fire or the like occurs in the flow path, only the seat ring 10 may be burned away from the ball seat 1. Even in this case, the fact that the ball seat 1 exhibits sealing properties against the ball valve body (fire-safe function) is preferable from the viewpoint of suppressing the spread of damage caused by fluid leakage from the ball valve due to a fire. From this viewpoint, the ball seat 1 is configured so that, if the seat ring 10 is burned away, the inner ring 30 contacts both the ball valve body and the seat retainer in the ball valve.

As described above, the first seat tapered surface 11 of the seat ring 10 is the contact surface for the ball valve body, and the second seat tapered surface 12 of the seat ring 10 is the contact surface for the seat retainer. From the above perspective, the shortest distance in the axial direction between the extension lines of these surfaces in the cross section of the ball seat 1 and the outer ring 20 is greater than the shortest distance in the axial direction between the extension lines and the inner ring 30. This will be explained in more detail with reference to the drawings.

Figure 4 is a diagram for explaining the relationship between the tapered surfaces in the ball seat according to the first embodiment of the present invention. In the cross section of the ball seat 1, the extension line L2 of the first seat tapered surface 11 does not intersect with either the outer ring 20 or the inner ring 30, and is separated from them. Similarly, the extension line L3 of the second seat tapered surface 12 does not intersect with either the outer ring 20 or the inner ring 30, and is separated from them.

As shown in the figure, in the same cross section, the first inner tapered surface 31 of the inner ring 30 is located inside the extension line L2 of the first seat tapered surface 11, and the second inner tapered surface 32 of the inner ring 30 is located inside the extension line L3 of the second seat tapered surface 12. The first inner tapered surface 31 is inclined so as to approach the extension line L2 of the first seat tapered surface 11 as it approaches the seat ring 10, and the second inner tapered surface 32 is inclined so as to approach the extension line L3 of the second seat tapered surface 12 as it approaches the seat ring 10. In other words, the first inner tapered surface 31 and the second inner tapered surface 32 have a larger inclination angle than the extension line L2 of the first seat tapered surface 11 and the extension line L3 of the second seat tapered surface 12, respectively. In this way, the distance between the first inner tapered surface 31 and the second inner tapered surface 32 is widest at the position closest to the seat ring 10, and the inner ring 30 supports the seat ring 10 on its inner diameter side with this widest surface.

If the seat ring 10 were to burn, the portions of the outer ring 20 and the inner ring 30 that are closest to the seat ring 10 on the ball valve body side or the seat retainer side would likely come into contact with the ball valve body or the seat retainer. That is, in the case of the outer ring 20, when the seat ring 10 burns, the radially inner end of the first outer tapered surface 22 may come into contact with the ball valve body, and the radially inner end of the second outer tapered surface 23 may come into contact with the seat retainer. In the case of the inner ring 30, when the seat ring 10 burns, the radially outer end of the first inner tapered surface 31 may come into contact with the ball valve body, and the radially outer end of the second inner tapered surface 32 may come into contact with the seat retainer.

Therefore, the sum of the distance G21 between the radially inner end of the first outer tapered surface 22 and the extension line L2 and the distance G22 between the radially inner end of the second outer tapered surface 23 and the extension line L3 is the shortest distance d20 in the axial direction between the extension line of the contact surface in the cross section and the outer ring 20. In addition, the sum of the distance G31 between the radially outer end of the first inner tapered surface 31 and the extension line L2 and the distance G32 between the radially outer end of the second inner tapered surface 32 and the extension line L3 is the shortest distance d30 in the axial direction between the extension line of the contact surface in the cross section and the inner ring 30. In the ball seat 1, the shortest distance d30 is designed to be smaller than the shortest distance d20. Thus, in the cross section of the ball seat 1, the gap between the part of the tapered surface of the inner ring 30 closest to the seat ring 10 and the extension line L2 of the first seat tapered surface 11 and the extension line L3 of the second seat tapered surface 12 is smaller than the gap between the part of the outer ring 20 closest to the seat ring 10 and the extension line L2 and extension line L3.

In this way, the ball seat 1 is constructed with a cross-sectional shape in which the axial length (width) gradually decreases from the outer periphery to the inner periphery. In the cross section of the ball seat 1, as with the tapered surfaces of each ring described above, the contour on one side in the axial direction is more inclined than the contour on the other side.

〔Ball valve〕
The ball seat 1 is applied to a ball valve. Fig. 5 is a cross-sectional view showing a structure of a ball valve according to a first embodiment of the present invention. Fig. 6 is a cross-sectional view showing a schematic enlargement of a portion A in Fig. 5 as viewed obliquely, and Fig. 7 is a cross-sectional view showing a schematic enlargement of a portion A in Fig. 5 as viewed from the front.

The ball valve 100 has a ball valve body 140, a seat retainer 130, and an annular ball seat 1 that is sandwiched between them to seal the space between them. The structure of the ball valve 100 will be further described below.

The ball valve 100 has a body 110, a lid portion 150, a ball valve body 140, a stem 160, and a bonnet 170.

The body 110 has a valve chamber 111 and a cylindrical portion 112 connected thereto from below. The valve chamber 111 has two flow passage openings 120, 120 that open at positions facing each other. In the valve chamber 111, a ball valve body 140 is rotatably arranged so as to communicate and block the flow passage openings 120, 120. In addition, the valve chamber 111 contains annular ball seats 1, 1 that are in close contact with the ball valve body 140 from each flow passage opening side, and seat retainers 130, 130 that are in contact with the ball seats 1, 1 from each flow passage opening side and are biased toward the ball valve body 140. The seat retainer 130 has a seal material 130a that is provided around its outer periphery. The seal material 130a is in contact with the inner peripheral wall surface of the flow passage opening 120, and seals between the seat retainer 130 and the inner peripheral wall surface. The sealant 130a is made of a fire-resistant material, such as graphite, so that it will not disappear in the event of a fire.

The cylindrical portion 112 is a cylindrical structure having a tube axis in the vertical direction (Z direction). One end of the cylindrical portion 112 (the lower end in the figure) is connected to the valve chamber portion 111 via an opening.

The inner lid portion 150 closes the opening of the valve chamber portion 111 on the cylindrical portion 112 side, separating the valve chamber portion 111 from the cylindrical portion 112.

The stem 160 is a generally cylindrical structure that penetrates the inner lid portion 150 and connects to the ball valve body 140. The stem 160 constitutes a valve shaft that extends in the Z direction in the figure. The stem 160 protrudes upward from the upper end of the body 110.

The bonnet 170 seals the opening at the other end (the upper end in the figure) of the cylindrical portion 112. The stem 160 passes through the bonnet 170 and is arranged so as to be rotatable relative to the bonnet 170. The bonnet 170 is detachably connected to the upper end of the body 110 by a bolt or the like.

A shaft seal is interposed between the inner lid portion 150 and the stem 160, and an outer circumferential seal having a pressure seal structure is interposed between the outer edge of the inner lid portion 150 and the opposing inner circumferential wall portion of the body 110. An operating unit (not shown) is fixed onto the bonnet 170. By rotating a handle installed on the operating unit, the stem 160 and the ball valve body 140 rotate, and the fluid flow path in the valve chamber portion 111 opens and closes.

In the ball valve 100, the ball seat 1 abuts against the ball valve body 140 at the first seat tapered surface 11, and against the seat retainer 130 at the second seat tapered surface 12. The outer peripheral surface of the outer ring 20 abuts against the inner lid portion 150. In the above state, the outer ring 20 and the inner ring 30 are both separated from the ball valve body 140 and the seat retainer 130 and do not come into contact with each other.

When comparing the outer ring 20 and the inner ring 30, the inner ring 30 is positioned further inward in the radial direction, and the distance between the surface of the ball valve body 140 and the seat retainer 130 is narrower.

Here, if a fire occurs in the flow passage and the flames propagate through the flow passage, only the resin seat ring 10 may melt or burn due to heat. However, when comparing the outer ring 20 and the inner ring 30, the inner ring 30 is located further inward in the radial direction, and the distance between the surface of the ball valve body 140 and the seat retainer 130 is narrower. In addition, the outer ring 20 is biased toward the outer periphery by the C-ring 40. Furthermore, the seat retainer 130 presses the ball seat 1 toward the ball valve body 140 along the axial direction. Therefore, while the seat ring 10 is burned, the first inner tapered surface 31 and the second inner tapered surface 32 of the seat retainer 130 abut against the ball valve body 140 and the seat retainer 130. In this state, the first outer tapered surface and the second outer tapered surface of the outer ring 20 do not abut against the ball valve body and the seat retainer. In this way, the ball seat 1 is configured so that when the seat ring 10 burns down, the inner ring 30 contacts both the ball valve body 140 and the seat retainer 130 before the outer ring 20.

In addition, in the ball valve 100, the position P2 of the radially innermost portion of the inner ring 30 is located further outward than the position P1 of the radially inner circumferential surface of the ball valve body 140 and the seat retainer 130.

Here, the state in which the seat ring has been lost due to a fire or the like will be further explained with reference to Figure 8. Figure 8 is a diagram for explaining the state when the seat ring 10 in the ball valve 100 is burned away. Figure 8 shows a schematic cross-sectional configuration of the ball seat and its surroundings in a state in which the seat ring 10 has been completely lost.

When the seat ring 10 has disappeared, a force acts on the remaining ring-shaped member in a direction that pushes the seat retainer 130 toward the ball valve body 140. This is because a spring or the like is arranged on the opposite side of the seat retainer 130 from the ball valve body 140, and the spring acts as a biasing force. In addition to this, the seat retainer 130 is sealed on its outer diameter side with a sealing material 130a, while the ball valve body 140 side contacts the inner ring 30, and the contact position becomes the sealing point. Therefore, the force due to the pressure difference (autofrettage force) caused by the fluid based on the difference in the sealing area is also generated as a force that pushes the seat retainer 130 toward the ball valve body 140.

These forces push the seat retainer 130 towards the ball valve body, which brings it into contact with the end faces of the inner ring 30 and the outer ring 20 on the seat retainer 130 side. At this time, the contact position between the seat retainer 130 and the inner ring 30 is on the outer diameter side of the second inner tapered surface 32, and the contact position between the seat retainer 130 and the outer ring 20 is on the inner diameter side of the second outer tapered surface 23. Due to the formation of these tapered surfaces, the respective contacts are formed linearly. Therefore, even when the seat ring 10 is missing, the seat retainer 130 and the inner ring 30 or the outer ring 20 can provide high sealing performance with each other.

On the other hand, on the ball valve body 140 side, the inner ring 30, which is pressed toward the ball valve body 140 by the seat retainer 130, comes into contact with the ball valve body 140. The contact position is on the outer diameter side of the first inner tapered surface 31. This contact is also formed in a line, so high sealing performance can be achieved.

In response to this, the outer ring 20 is pushed toward the ball valve body 140 by the seat retainer 130, but due to the relationship between the distances G21, G22, G31, and G32 described above, the inner ring 30 and the ball valve body 140 come into contact first. Therefore, the inner ring 30, which is in contact with both the seat retainer 130 and the ball valve body 140, becomes a blockage, and the outer ring 20 and the ball valve body 140 do not come into contact, and a small gap c is formed between them.

In this way, in this embodiment, even if the ball seat is destroyed by fire or the like, a fire-safe function can be achieved that allows the inner ring 30 to maintain its sealing performance.

According to the above explanation alone, in a state where the seat ring 10 is lost due to, for example, a fire, the inner ring 30 contacts both the ball valve body 140 and the seat retainer 130 to provide a seal, but the outer ring 20 does not provide a seal because there is a gap between it and the ball valve body 140. However, in reality, the seat ring 10 may not disappear completely and parts of it may remain, or the inner ring 30 or the outer ring 20 may tilt due to the influence of fluid pressure, so it is possible that the inner ring 30 does not form a seal and the outer ring 20 contacts the ball valve body 140 and the seat retainer 130 to provide a seal.

In this way, in the ball valve 100 of this embodiment, even if the seat ring 10 is lost due to a fire or the like, the inner ring 30 provides high sealing performance. Also, even if the inner ring 30 does not provide a good seal, the outer ring 20 provides sealing performance. Because the ball valve 100 can provide such a double fire-safe function, it can provide high safety without fluid leakage even in the event of a fire or the like.

However, the seal provided by the outer ring 20 is close to the radial position of the sealing material 130a on the outer diameter side of the seat retainer 130, so the self-sealing force described above is weak, and this may result in a weaker seal. In this embodiment, the tapered surfaces on both sides of the outer ring and inner ring are designed to satisfy the above-mentioned predetermined distances G21, G22, G31, and G32, making it easier for the inner ring 30 to form a seal even if the seat ring 10 is burned down. This allows for a particularly excellent fire-safe function.

[Major effects]
The ball seat 1 has an annular seat ring 10, an annular outer ring 20 that holds the seat ring 10 on the outer periphery side of the seat ring 10, and an annular inner ring 30 that holds the seat ring 10 on the inner periphery side of the seat ring 10. The inner ring 30 has a cross-sectional shape that is convex toward the inside in the radial direction, and the width of the inner ring gradually increases toward the outside in the radial direction.

In this embodiment, the ball seat 1 is disposed in the valve chamber 111 simply by being sandwiched between the ball valve body 140 and the seat retainer 130. In the ball valve 100, although the upper portion abuts against the inner lid portion 150, there is no other structure for fixing the ball seat 1 in the valve chamber 111. In other words, the ball seat 1 is basically fixed and positioned by the abutment of the ball valve body 140 at the first seat tapered surface 11 and the abutment of the seat retainer 130 at the second seat tapered surface 12. Therefore, the ball seat 1 is susceptible to forces that cause misalignment and deformation due to the sliding of the seal surface accompanying the rotation of the ball valve body 140 or the application of fluid pressure from the flow path.

In contrast, in the ball seat 1, the seat ring 10 is sandwiched between the outer ring 20 on its outer diameter side and the inner ring 30 on its inner diameter side. Therefore, when the ball valve body 140 rotates, for example, a torsional force is applied to the ball seat 1 due to the sliding of the ball valve body 140 against the first seat tapered surface 11. However, the outer ring 20 and the inner ring 30 prevent torsional deformation.

In addition, when fluid pressure is applied to the ball seat 1 from the flow path side, a force is applied that causes the fluid to flow out to the contact surface between the first seat tapered surface 11 and the ball valve body 140 or the contact surface between the second seat tapered surface 12 and the seat retainer 130, and a force acts to tilt the ball seat 1 toward the ball valve body 140 or the seat retainer 130. However, due to the support provided by the outer ring 20 and the inner ring 30, such forces can be resisted, and deformation of the ball seat 1 is unlikely to occur.

As a result, even though the ball seat 1 is relatively loosely fixed in position within the valve chamber 111, it is not prone to deformation, such as twisting, even when subjected to external forces. Therefore, the ball seat 1 is able to exhibit high sealing properties.

In this way, in the ball seat 1, the inner ring 30 holds the radially inner side of the seat ring 10 so that the seat ring 10 does not deform. Therefore, even if the ball seat 1 is exposed to extremely low temperatures, deformation such as a reduction in diameter of the seat ring 10 can be suppressed, and the sealing position of the ball seat 1 can be properly maintained.

In particular, the inner ring 30 has a shape that widens radially outward, and its relatively wide circumferential outer surface abuts against most of the inner peripheral surface of the seat ring 10, holding the seat ring 10. This is effective in holding the seat ring 10 more firmly and preventing it from coming off the inner ring 30 when the seat ring 10 tries to contract. In particular, the inner ring 30 has a thick cross-sectional shape that widens toward the outer diameter side, so it has strength that is particularly strong against forces in the direction of diameter contraction, and is excellent in preventing the contraction of the seat ring 10 when cryogenic fluid is passed through it.

The inner ring 30 is not simply a ring made of a thin plate, but has a generally trapezoidal cross section and a certain degree of thickness. Therefore, for example, when the first inner tapered surface 31 and the second inner tapered surface 32 are machined by cutting during manufacture, the inner ring 30 has the strength to withstand the machining. Furthermore, compared to a thin plate, it is easier to fix the inner ring 30 with a jig during machining. In this way, the inner ring 30 also has advantages in terms of manufacturing.

In addition, even though the inner ring 30 is located radially inside the seat ring 10 in this manner, inside the ball valve 100, it has a shape that narrows radially inward, so it does not come into contact with the ball valve body 140, which has a shape that increases in diameter toward the center, and does not interfere with its rotational movement, allowing for smooth valve body operation.

Furthermore, the ball seat 1 is also excellent in terms of improving sealing performance. Usually, the ball seat in a ball valve is held only by being sandwiched between the seat retainer and the ball valve body, and is not supported in the radial direction of the ball seat. In addition, when the ball valve body in a ball valve is rotated, fluid may flow into the cavity (the space that houses the ball valve body 140 in the valve chamber 111) at an intermediate opening. In this case, the fluid flows through a narrow space such as the gap formed by the ball seat and the through hole of the ball valve body. Therefore, the flow speed is fast, and the force that draws the ball seat toward the cavity may act strongly on the ball seat. Conversely, when the fluid pressure in the cavity increases abnormally, the fluid may rapidly flow from the cavity through the aforementioned gap toward the flow path in the valve chamber. In this case, the force that draws the ball seat toward the flow path may also act strongly on the ball seat. In the conventional ball seat, the seat ring may be crushed or deformed by the strong flow of fluid that may occur at the intermediate opening as described above, and may come out of its designated position in the ball valve.

In contrast, in the ball seat 1 of this embodiment, the seat ring 10 is fixed in a state in which it is sandwiched between the inner ring 30 and the outer ring 20 in the radial direction. Therefore, the seat ring 10 is not easily deformed even by the flow of fluid outside the flow path as described above, and the ball seat 1 does not move from its predetermined position in the ball valve 100. Therefore, problems such as seat detachment are unlikely to occur. In particular, the outer ring 20 is arranged so as to cover substantially the entire width in the axial direction of the outer periphery of the seat ring 10, and the inner ring 30 has a specific cross-sectional shape that expands in diameter toward the outer diameter side, so that the inner ring 30 can be arranged so as to cover substantially the entire width in the axial direction of the inner periphery of the seat ring 10. In this case, deformation such as the seat ring 10 being tilted toward the ball valve body 140 side or the seat retainer 130 side is also unlikely to occur in the ball seat 1, and the seat ring 10 is even less likely to fall off the ball seat 1.

In addition, in the ball seat 1, the inner ring 30 has a first inner tapered surface 31 on one axial side (the ball valve body 140 side) and a second inner tapered surface 32 on the other axial side (the seat retainer 130 side), and the distance between the two tapered surfaces gradually increases radially outward.

In this way, both side surfaces of the inner ring 30 are tapered surfaces. In particular, as described above, the first inner tapered surface 31 and the second inner tapered surface 32 have a larger inclination angle than the extension line L2 of the first seat tapered surface 11 and the extension line L3 of the second seat tapered surface 12, respectively. This makes it possible to maximize the width of the outer diameter side surface of the inner ring 30 that holds the seat ring 10, while minimizing the thickness of the inner ring 30. This makes it possible to achieve a high level of both holding the seat ring 10 and smooth valve body operation.

Furthermore, in the unlikely event that the ball seat 1 is burned or the seat ring 10 is lost, the first inner tapered surface 31 may contact the surface of the ball valve body 140, and the second inner tapered surface 32 may contact the seat retainer 130. Therefore, even if the seat ring 10 is burned, the inner ring 30 maintains the sealing between the ball valve body 140 and the seat retainer 130. In this way, the above-mentioned ball seat 1 can further exhibit a fire-safe function. In particular, when both tapered surfaces contact the ball valve body 140 or the seat retainer 130, a linear contact that is advantageous for sealing can be formed, so that high sealing properties can be exhibited even during fire-safe.

In addition, in the ball seat 1, the inclination angle of the first inner tapered surface 31 relative to the radial direction is greater than that of the second inner tapered surface 32.

The ball valve body 140 has a spherical surface, and the seat retainer 130 has a tapered surface on the radially inner side where the distance from the ball valve body 140 surface gradually decreases in the axial direction. The tapered surface on the ball valve body 140 side of the seat retainer 130 is more "upright" than the spherical surface of the ball valve body 140 in order to press the ball seat 1 toward the ball valve body 140. The both side surfaces of the inner ring 30 described above may also have a tendency similar to the surface shape of the adjacent components in the axial direction. This allows the line seal during the fire-safe state described above to be formed even better.

The ball valve 100 is a top-entry type ball valve. Therefore, when assembling the ball valve 100, the ball seat 1 is inserted together with the ball valve body 140 through the cylindrical portion 112 into the valve chamber portion 111 in which the seat retainer 130 is pre-installed. Therefore, the tapered surfaces on both sides of the inner ring 30 also function as good guides for the seat retainer 130 and the ball valve body 140. Therefore, the above structure is advantageous from the viewpoint of more easily positioning the ball seat 1 in the ball valve 100.

In addition, in the ball seat 1, the seat ring has a first seat tapered surface that abuts against the ball valve body on one side in the axial direction, and a second seat tapered surface that abuts against the seat retainer on the other side in the axial direction. In the cross section of the ball seat, the gap between the part of the tapered surface of the inner ring closest to the seat ring and the extension line of the first seat tapered surface and the extension line of the second seat tapered surface is smaller than the gap between the part of the outer ring closest to the seat ring and the extension line of the first seat tapered surface and the extension line of the second seat tapered surface. In this way, a configuration in which the gap formed on both sides of the inner ring 30 based on the tapered surface of the seat ring 10 is smaller than the gap formed on both sides of the outer ring 20 is also effective from the viewpoint of realizing a fire-safe function.

In the ball seat 1, the outer ring 20 has an outer protrusion 21 that protrudes radially inward on one side of the cross section, and the inner ring 30 has an inner protrusion 33 that protrudes radially outward on the other side of the cross section. The seat ring 10 engages with the outer protrusion 21 at the outer cutout 13 on one radially outer side of the cross section, and engages with the inner protrusion 33 at the inner cutout 14 on the other radially inner side.

In this way, the seat ring 10 is held by the outer ring 20 and the inner ring 30, with the corners of the cross-sectional shape surrounded diagonally on the radially outer side from the ball valve body side and on the radially inner side from the seat retainer side. The flow of fluid from the flow path to the cavity as described above occurs mainly by expanding the diameter of the ball seat 1 in the direction of the ball valve body 140, but the ball seat 1 has an outer protrusion 21 formed in this direction. Therefore, it is possible to reliably prevent the ball seat 1 from slipping out and deforming in this direction.

In addition, if an abnormal pressure rise in the cavity causes a flow from the cavity into the flow path, a force is applied to the ball seat 1 that draws it in toward the inner diameter in a direction away from the valve body, but the inner protrusion 33 is formed in the ball seat 1 in this direction. This is advantageous in resisting the force in the drawing direction. In this way, the outer protrusion 21 and the inner protrusion 33 are provided in diagonal positions that can exactly resist the direction in which the high-speed flow of the fluid into and out of the flow path described above occurs. Therefore, even if the force of the flow that draws in the ball seat 1 is applied to the ball seat 1, deformation of the ball seat 1 can be further suppressed. This is also more effective in terms of maintaining the shape of the seat ring 10 even when the ball seat 1 is exposed to extremely low temperatures.

In addition, the outer protrusion 21 on the outer ring 20 and the inner protrusion 33 on the inner ring 30 are also effective when mounting the outer ring 20 to the seat ring 10. That is, when mounting the outer ring 20 to the seat ring 10, first, mount the C-ring 40 in the groove 15 of the seat ring 10, and then fit the seat ring 10 on the inner periphery of the outer ring 20. In this case, the outer cutout 13 on the seat ring 10 fits in so as to just engage with the step portion of the outer protrusion 21 of the outer ring 20. At this time, the seat ring 10 and the outer ring 20 are naturally aligned by both steps, and the two are fixed in the correct positional relationship. Similarly, when the inner ring 30 is fitted on the inner periphery of the seat ring 10, the inner protrusion 33 of the inner ring 30 is aligned so as to fit into the inner cutout 14 of the seat ring 10. Therefore, the two are fixed in the correct positional relationship. The above-mentioned effect of the inner ring 30 and the outer ring 20 in preventing the seat ring 10 from shifting or deforming can be particularly pronounced when the seat ring 10 and the inner ring 30, and the seat ring 10 and the outer ring 20, are securely fitted together. Therefore, this effect can be further increased by the engagement of these stepped portions.

In addition, the inner ring 30 is formed with an inner protrusion 33, and the outer ring 20 is formed with an outer protrusion 21, so that the inner ring 30 and the outer ring 20 both have a substantially L-shaped cross-sectional shape. This shape can exhibit high strength against twisting and bending compared to a simple plate-shaped ring. By having such a cross-sectional shape, the reinforcing effect of the inner ring 30 and the outer ring 20 described above is further enhanced.

In addition, in the ball valve 100, the ball seat 1 is configured so that, when the seat ring 10 is burned, the inner ring 30 contacts both the ball valve body 140 and the seat retainer 130 before the outer ring 20. This configuration can be appropriately configured using various components or combinations thereof that prioritize contact with the tapered surface of the inner ring 30 when the seat ring 10 is burned. In this way, a seal can be reliably formed by the inner ring 30 when the seat ring is burned due to a fire or the like.

The outer ring 20 has a cross-sectional shape that is long (horizontally long) in the axial direction. Therefore, if pressure is applied in the compression direction when the seat ring 10 is burned away, tilting or the like may occur. However, the cross-sectional shape of the inner ring 30 is not as long as that of the outer ring 20. Therefore, it is easier to be supported between the ball valve body 140 and the seat retainer 130 in contact with both without tilting or the like, and it is easier to achieve better sealing performance. This type of configuration is more effective in terms of realizing the fire-safe function described above.

In addition, in the ball valve 100, the innermost portion of the inner ring 30 of the ball seat 1 is located radially at the same position as or outside one or both of the innermost portion of the ball valve body 140 and the innermost portion of the seat retainer 130. This configuration is preferable from the viewpoint of allowing the fluid to flow smoothly in the ball valve 100 without interfering with the intended flow path of the inner ring 30 of the ball valve 100. It is also more effective from the viewpoint of preventing interference with the operation of the ball valve body 140.

[Modifications]
As long as the cross-sectional shape of the inner ring is a shape that is convex radially inward and the width of the inner ring gradually increases radially outward, the inner ring may have a side surface other than the tapered surface described above.

In addition, various configurations and combinations of configurations that provide a fire-saving function are possible. It may also include configurations other than the tapered surface, its positional relationship, and the use of a C-ring as described above.

The position of the inner peripheral surface of the inner ring in the ball valve may be specified as a specific position relative to the position of the seat ring's contact surface on the ball seat. From the viewpoint of preventing interference with the operation of the ball valve, it is desirable for the position of the inner peripheral surface of the inner ring to be located at least on the outer diameter side of the intersection point formed by connecting the extension line L2 of the first seat tapered surface 11 and the extension line L3 of the second seat tapered surface 12. From the viewpoint of preventing interference with the flow of fluid in the ball valve, the suitable position of this inner peripheral surface is determined by the positional relationship with the ball valve body and the seat retainer when the ball seat is attached to the ball valve.

The ball seat may further have a configuration that indicates the orientation of the ball seat when it is attached to the ball valve. Examples of such configurations include an arrow that indicates the position of the ball valve body when it is attached.

〔summary〕
As is clear from the above description, the ball seat (1) of the first aspect of the present invention is an annular ball seat that is sandwiched between a ball valve body (140) and a seat retainer (130) in a ball valve (100) to seal between them, and includes an annular seat ring (10), an annular outer ring (20) that contacts the seat ring on the outer periphery side of the seat ring, and an annular inner ring (30) that contacts the seat ring on the inner periphery side of the seat ring, and the cross-sectional shape of the inner ring in the radial direction is a shape that is convex toward the inside in the radial direction, and the width of the inner ring gradually increases from the inside in the radial direction toward the seat ring. According to the first aspect, a technology can be provided that allows the ball seat to exhibit the desired sealing performance regardless of the usage environment.

In the ball seat of the second aspect of the present invention, in the first aspect, the inner ring has a first inner tapered surface (31) on one axial side and a second inner tapered surface (32) on the other axial side, and the distance between the two tapered surfaces gradually increases from the radial inside toward the seat ring. The second aspect is even more effective in terms of improving sealing performance during fire-safe operation.

In the ball seat of the third aspect of the present invention, the inclination angle of the first inner tapered surface relative to the radial direction is larger than the inclination angle of the second inner tapered surface relative to the radial direction in the second aspect. The third aspect is even more effective from the viewpoint of improving the sealing performance during fire-safe operation and from the viewpoint of facilitating installation of the ball seat by top entry.

In the fourth aspect of the ball seat of the present invention, in the second or third aspect, the seat ring has a first seat tapered surface (11) that abuts against the ball valve body on one side in the axial direction, and a second seat tapered surface (12) that abuts against the seat retainer on the other side in the axial direction. In the radial cross section of the ball seat, the first inner tapered surface and the second inner tapered surface are formed between the extension line (L2) of the first seat tapered surface and the extension line (L3) of the second seat tapered surface, respectively. Furthermore, the first inner tapered surface is inclined so as to approach the extension line of the first seat tapered surface as it approaches the seat ring, and the second inner tapered surface is inclined so as to approach the extension line of the second seat tapered surface as it approaches the seat ring. The fourth aspect is even more effective in terms of expressing the fire-safe function.

The ball seat of the fifth aspect of the present invention is any one of the second to fourth aspects, in which the seat ring has a first seat tapered surface that abuts on one axial side of the ball valve body and a second seat tapered surface that abuts on the seat retainer on the other axial side. In addition, in a radial cross section of the ball seat, the gap between the part of the tapered surface of the inner ring closest to the seat ring and the extension line of the first seat tapered surface and the extension line of the second seat tapered surface is smaller than the gap between the part of the outer ring closest to the seat ring and the extension line of the first seat tapered surface and the extension line of the second seat tapered surface. The fifth aspect is even more effective in terms of realizing a fire-safe function.

The ball seat of the sixth aspect of the present invention is any one of the first to fifth aspects, in which the outer ring has an outer protrusion (21) protruding radially inward on one side of the radial cross section, the inner ring has an inner protrusion (33) protruding radially outward on the other side of the radial cross section, and the seat ring has an outer cutout (13) that engages with the outer protrusion on one radially outer side of the radial cross section, and an inner cutout (14) that engages with the inner protrusion on the other radially inner side. The sixth aspect is even more effective in terms of preventing deformation and detachment of the seat link at the ball seat.

The ball valve of the seventh aspect of the present invention has a ball valve body, a seat retainer, and an annular ball seat that is sandwiched between them to seal the space between them, and the ball seat is a ball seat described in any of the first to sixth aspects. According to the seventh aspect, a technology can be provided that allows the ball seat to exhibit the desired sealing properties regardless of the usage environment.

The eighth aspect of the ball valve of the present invention is the seventh aspect, but the ball seat is configured such that, in the event of seat ring burning, the inner ring contacts both the ball valve body and the seat retainer before the outer ring. The eighth aspect is even more effective in terms of realizing a fire-safe function.

The ninth aspect of the ball valve of the present invention is the seventh or eighth aspect, in which the innermost part of the inner ring of the ball seat is located radially at the same position as or outside one or both of the innermost part of the ball valve body and the innermost part of the seat retainer. The ninth aspect is even more effective in terms of suppressing interference with the normal fluid flow in the ball valve and the operation of the ball valve body.

According to the present invention, an excellent ball seat can be obtained even in an extremely low temperature environment, and a fire-saving function that can exhibit sealing properties even when the valve is lost can also be exhibited. Therefore, the present invention is suitable for ball valves for liquid hydrogen fluids and ball seats therefor. This invention is expected to make a significant contribution to the creation of a hydrogen society, and is expected to contribute to the achievement of Goal 7 of the Sustainable Development Goals (SDGs) proposed by the United Nations, "Affordable and Clean Energy."

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.

REFERENCE SIGNS LIST 1 ball seat 10 seat ring 11 first seat tapered surface 12 second seat tapered surface 13 outer cutout portion 14 inner cutout portion 15, 24 groove 20 outer ring 21 outer protruding portion 22 first outer tapered surface 23 second outer tapered surface 30 inner ring 31 first inner tapered surface 32 second inner tapered surface 33 inner protruding portion 40 C-ring 100 ball valve 110 body 111 valve chamber portion 112 cylindrical portion 120 flow passage opening portion 130 seat retainer 130a sealing material 140 ball valve body 150 inner lid portion 160 stem 170 bonnet

Claims (9)

A ball valve has an annular ball seat that is sandwiched between a ball valve body and a seat retainer to seal the space between them,
An annular seat ring;
an annular outer ring that contacts the seat ring on an outer circumferential side of the seat ring;
an annular inner ring in contact with the seat ring on an inner circumferential side of the seat ring;
The cross-sectional shape of the inner ring in the radial direction is a shape that is convex toward the inside in the radial direction, and the width of the inner ring is gradually increased from the inside in the radial direction toward the seat ring.
Ball seat. The inner ring has a first inner tapered surface on one axial side and a second inner tapered surface on the other axial side,
2. The ball seat according to claim 1, wherein the distance between the tapered surfaces gradually increases from the radially inner side toward the seat ring. The ball seat according to claim 2, wherein the inclination angle of the first inner tapered surface relative to the radial direction is greater than the inclination angle of the second inner tapered surface relative to the radial direction. the seat ring has a first seat tapered surface that contacts the ball valve body on one side in the axial direction and a second seat tapered surface that contacts the seat retainer on the other side in the axial direction,
In a radial cross section of the ball seat, the first inner tapered surface and the second inner tapered surface are respectively formed between an extension line of the first seat tapered surface and an extension line of the second seat tapered surface, and
3. The ball seat of claim 2, wherein the first inner tapered surface is inclined so as to approach an extension of the first seat tapered surface as it approaches the seat ring, and the second inner tapered surface is inclined so as to approach an extension of the second seat tapered surface as it approaches the seat ring. the seat ring has a first seat tapered surface that contacts the ball valve body on one side in the axial direction and a second seat tapered surface that contacts the seat retainer on the other side in the axial direction,
3. The ball seat of claim 2, wherein in a radial cross section of the ball seat, a gap between a portion of the tapered surface of the inner ring closest to the seat ring side and an extension line of the first seat tapered surface and an extension line of the second seat tapered surface is smaller than a gap between a portion of the outer ring closest to the seat ring side and an extension line of the first seat tapered surface and an extension line of the second seat tapered surface. the outer ring has an outer protruding portion protruding radially inward on one side in a radial cross section,
the inner ring has an inner protruding portion protruding radially outward on the other side in a cross section in the radial direction,
2. The ball seat according to claim 1, wherein the seat ring has an outer cutout portion on one radially outer side in a radial cross section thereof that engages with the outer protrusion, and an inner cutout portion on the other radially inner side that engages with the inner protrusion. A ball valve having a ball valve body, a seat retainer, and an annular ball seat that is sandwiched between them to seal the space therebetween,
A ball valve, wherein the ball seat is the ball seat according to any one of claims 1 to 6. The ball valve according to claim 7, wherein the ball seat is configured such that the inner ring contacts both the ball valve body and the seat retainer when the seat ring burns down. The ball valve according to claim 7, wherein the radially innermost portion of the inner ring of the ball seat is located at the same position as or outside one or both of the radially innermost portion of the ball valve body and the radially innermost portion of the seat retainer.

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