WO2024143518A1

WO2024143518A1 - Ball valve

Info

Publication number: WO2024143518A1
Application number: PCT/JP2023/047174
Authority: WO
Inventors: 正澄船渡
Original assignee: 株式会社キッツ
Priority date: 2022-12-29
Filing date: 2023-12-28
Publication date: 2024-07-04

Abstract

The present invention achieves a ball valve with which it is possible to sufficiently seal a valve chamber with respect to a cylindrical body part even when the ball valve has a large diameter. A ball valve (1) has a pressure seal structure comprising a pressing member (70) that is fixed to an inner lid (20) partitioning a valve chamber (11), and comes into contact with a regulating part protruding from an inner circumferential surface of the valve chamber (11), thereby improving sealing performance of a sealing member (60) between the inner lid (20) and the pressing member (70).

Description

Ball valve

The present invention relates to a ball valve.

Ball valves are useful as valves for controlling the flow of large volumes of fluid, and various types have been studied to suit a variety of conditions. For example, a ball valve for extremely low-temperature fluids such as liquefied hydrogen (-253°C) is known in which the valve body includes a valve chamber in which a ball valve element is housed and a cylindrical portion connected to it, and the valve chamber is sealed from the cylindrical portion by two plates that make up the inner lid. In this ball valve, the plate on the cylindrical portion side of the inner lid is fixed to the valve body in the axial direction, and the plate on the valve chamber side presses the seal member interposed between the two plates against the plate on the cylindrical portion side under the internal pressure of the valve chamber, resulting in the valve chamber being sealed from the cylindrical portion (see, for example, Patent Document 1).

International Publication No. 2021/172457

However, in the conventional technology described above, in order to seal the valve chamber, through which the fluid flows, from the cylindrical portion, it is necessary to fix the plate on the cylindrical portion side to the valve body in the axial direction. Therefore, the larger the size of the ball valve, the greater the force acting on the plate, which can cause it to distort, and it can become difficult to fix the plate to the valve body, or the plate can be insufficiently fixed in the axial direction. These types of problems tend to become more pronounced as the diameter of the ball valve becomes larger.

One aspect of the present invention aims to realize a ball valve in which the valve chamber can be adequately sealed against the cylindrical portion even in a large-diameter ball valve.

In order to solve the above problems, a ball valve according to one embodiment of the present invention has two or more flow passage openings which serve as a flow passage for a fluid and a accommodating opening through which a ball valve body can pass, and comprises a valve chamber in which the ball valve body is accommodated so as to be rotatable and capable of opening and closing the flow passage openings, a cylindrical portion connected to the valve chamber at the accommodating opening, a middle cover portion which closes the accommodating opening of the valve chamber and separates the valve chamber from the cylindrical portion at one end side of the cylindrical portion, a bonnet which closes the opening at the other end side of the cylindrical portion, a rotatable stem which penetrates the bonnet and the middle cover portion and is connected to the ball valve body, and a valve chamber side which is connected to the ball valve body. and an outer periphery seal part having a pressure seal structure in which the sealability between the outer edge of the middle lid part and the inner wall surface of the valve chamber increases as the pressure on the middle lid part from the pressure increases. The outer periphery seal part includes a seal member stored in the gap between the outer edge of the middle lid part and the inner wall surface of the valve chamber, and a pressing member that overlaps the middle lid part from the barrel part side, has a gap between it and the middle lid part, is connected to the middle lid part so that it can move toward and away from the middle lid part, and sandwiches the seal member between the outer edge of the middle lid part and the inner wall surface of the valve chamber, and restricts movement toward the barrel part.

According to one aspect of the present invention, the valve chamber can be adequately sealed against the cylindrical portion even in a large-diameter ball valve.

1 is a diagram showing a schematic appearance of a ball valve according to an embodiment of the present invention; 2 is a cross-sectional view showing a cross section of the ball valve taken along line AA shown in FIG. 1. 3 is a schematic cross-sectional view of the ball valve taken along line BB in FIG. 2. FIG. 4 is a partially see-through view of the cross section shown in FIG. 3 . 3 is a diagram showing a schematic cross section of a portion C shown in FIG. 2 . FIG. 3 is a diagram showing another cross section of the portion C shown in FIG. 2 . FIG. 3 is a diagram showing another cross section of the portion D shown in FIG. 2 . FIG.

One embodiment of the present invention will be described in detail below. Figure 1 is a diagram showing a typical appearance of a ball valve according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view of the ball valve taken along line A-A in Figure 1. In the following description, the Z direction in the diagram is also referred to as the vertical direction, one side of the vertical direction is also referred to as the upper or lower direction depending on the position shown in the diagram, and one or both of the X and Y directions are also referred to as the horizontal direction.

〔overall structure〕
As shown in FIG. 1 , the ball valve 1 has a body 10 , a lid portion 20 , a ball valve element 30 , a stem 40 and a bonnet 50 .

The body 10 has, from below, a valve chamber 11 and a cylindrical portion 12 connected to the valve chamber 11. The valve chamber 11 has a first flow passage opening 111 which serves as a flow passage for the fluid, a second flow passage opening 112, and a housing opening 113 through which the ball valve body 30 can pass from the cylindrical portion 12 side. The valve chamber 11 also has a recess 114 in the center of its bottom. The recess 114 forms a roughly cylindrical space at the bottom of the valve chamber 11. The first flow passage opening 111 and the second flow passage opening 112 have the same diameter. The diameter is greater than 10 inches, for example, 20 inches or more.

The cylindrical portion 12 is a cylindrical structure with a tube axis in the vertical direction (Z direction). One end of the cylindrical portion 12 (the lower end in the figure) is connected to the valve chamber portion 11 at the accommodation opening 113 of the valve chamber portion 11.

The inner lid portion 20 closes the accommodation opening 113 of the valve chamber portion 11 and separates the valve chamber portion 11 from the cylindrical portion 12 at one end side of the cylindrical portion 12. The configuration of the inner lid portion 20 will be explained further in the explanation of the sealing structure later.

The ball valve body 30 is accommodated in the valve chamber 11. The ball valve body 30 has a generally spherical shape with the upper and lower parts cut out, and has a through hole 31 that serves as a flow path, and a protrusion 32 that protrudes downward (Z direction) from the lower part of the ball valve body 30. The through hole 31 is formed in the ball valve body 30 in a direction (horizontal direction in the figure) perpendicular to the Z direction (vertical direction in the figure) that is the axial direction of the stem 40 connected to the ball valve body 30. The diameter of the through hole 31 is generally the same as the diameter of the first flow path opening 111 and the second flow path opening 112. The protrusion 32 is a generally cylindrical part and has generally the same shape as the cavity of the recess 114. The protrusion 32 is fitted into the recess 114.

In addition, the valve chamber 11 contains

annular ball seats

115, 115 that are in close contact with the ball valve body 30 from each fluid opening side, and

seat retainers

116, 116 that are in contact with the

ball seats

115, 115 from each fluid opening side and are biased toward the ball valve body 30. The valve chamber 11 also has a circumferential groove 117 near the boundary with the cylindrical portion 12 in the Z direction.

The stem 40 is a generally cylindrical structure that penetrates the inner lid portion 20 and connects to the ball valve body 30. The stem 40 constitutes a valve shaft that extends in the Z direction. Between the stem 40 and the inner lid portion 20, there is an axis seal structure constructed in the inner lid portion 20. The axis seal structure will be described in further detail later. The stem 40 protrudes above the upper end of the body 10.

The bonnet 50 seals the opening at the other end (the upper end in the figure) of the cylindrical portion 12. The stem 40 passes through the bonnet and is arranged to be rotatable relative to the bonnet 50. The bonnet 50 is detachably connected to the upper end of the body 10 by a bolt or the like. In this embodiment, the bonnet 50 is structured to seal the other end of the cylindrical portion 12, but the fluid in the valve chamber 11 hardly flows above the inner lid portion 20, i.e., into the cylindrical portion 12, due to the pressure seal structure and shaft seal structure described below. Therefore, the sealing performance of the bonnet 50 is not required to be as high as that of the inner lid portion 20. The bonnet 50 only needs to close the cylindrical portion 12 via a gasket or the like to prevent excess fluid from flowing out of the cylindrical portion 12 or the intrusion of external dust and dirt.

In addition, an operating unit (not shown) is fixed onto the bonnet 50. The operating unit has a rotatable handle and is connected to the stem 40 so that the rotational motion of the handle can be transmitted as rotational motion of the stem 40. Depending on the amount of rotation of the handle, the stem 40 and the ball valve body 30 connected thereto rotate around the central axis of the ball valve 1.

[Peripheral seal part]
The ball valve 1 further has an outer circumferential seal portion between the outer edge of the inner lid portion 20 and the opposing inner circumferential wall portion of the body 10. The outer circumferential seal portion will be described below. Fig. 3 is a schematic diagram showing a cross section of the ball valve when cut along line B-B shown in Fig. 2, and Fig. 4 is a see-through diagram of a portion of the cross section shown in Fig. 3. Fig. 4 particularly shows a state in which the pressing member 93 has been removed, the cylindrical portion 12 above the groove 117 has been seen through, and the bolts for fixing the pressing member 70 have been removed.

FIG. 5 is a schematic diagram showing one cross section of part C shown in FIG. 2, and FIG. 6 is a schematic diagram showing another cross section of part C shown in FIG. 2. FIG. 5 is a schematic diagram showing a cross section at a position where a clamping bolt 77 that fixes a wedge member 76 (described below) is cut. FIG. 6 is a schematic diagram showing a cross section at a position where a bolt 75, a spacer 74, and a bolt hole 24 (described below) are cut.

The middle lid portion 20 is a member in which the stem 40 is inserted into its central through-hole, which fits into the accommodation opening 113 of the valve chamber portion 11 in the body and reaches the inner peripheral edge of the valve chamber portion 11. The middle lid portion 20 has a through-hole in the center when viewed in a plane. The middle lid portion 20 has a substantially disk-shaped main body portion 21 that reaches the edge of the valve chamber portion 11 that is connected to the cylindrical portion 12 in the XY plane direction, a convex portion 22 that protrudes from the main body portion 21 toward the cylindrical portion 12 around the through-hole, and a fitting portion 23 that protrudes from the main body portion 21 toward the valve chamber portion 11 and fits into the accommodation opening 113.

The convex rib portion 22 has a plurality of bolt holes 24 extending in the Z direction. In addition, a plurality of bolt holes 25 extending in the Z direction are formed on the outer peripheral edge of the body portion 21 on the cylindrical portion 12 side. Furthermore, a step portion 26 is provided around the outer peripheral edge of the body portion 21 on the cylindrical portion 12 side, which is one step lower than the main surface of the body portion 21 on the cylindrical portion 12 side. The step portion 26 forms a gap between the outer edge of the middle lid portion 20 and the inner wall surface of the valve chamber portion 11, which is surrounded by the inner wall surface of the valve chamber portion 11 and the outer wall surface of the middle lid portion 20, which are parallel to each other along the vertical direction, and the bottom surface of the inclined surface whose distance to the inner wall surface of the valve chamber portion 11 gradually decreases vertically downward.

The sealing member 60 is a member that has a circular shape when viewed in a plane. The cross-sectional shape of the sealing member 60 has inner and outer wall surfaces that are parallel to each other, a top surface that runs horizontally, and a slanted bottom surface that becomes longer from the top surface toward the outer periphery. The material of the sealing member 60 is, for example, graphite or a resin such as polychlorotrifluoroethylene (PCTFE) or ultra-high molecular weight polyethylene (UHMW-PE). The sealing member 60 is stored in the gap formed by the step 26 of the inner lid portion 20 and the inner wall surface of the valve chamber portion 11 at the outer edge of the inner lid portion 20.

The pressing member 70 has a generally circular ring shape when viewed in a plan view. The pressing member 70 has a convex ridge portion 71 that protrudes toward the valve chamber portion 11 at its outer periphery, a step 72 formed on the cylindrical portion 12 side of the outer periphery, and a hole 73 that passes vertically through the pressing member 70. The lower surface of the convex ridge portion 71 is located opposite the upper surface of the seal member 60.

The holes 73 are formed so as to be arranged at equal intervals along the circumferential direction of the pressing member 70. The holes 73 are formed at positions that overlap the bolt holes 24 of the inner lid portion 20 in the Z direction. A tubular spacer 74 is inserted into each of the holes 73 of the pressing member 70. The spacer 74 is made of, for example, stainless steel, has an outer diameter that is approximately the same as the inner diameter of the hole 73, is fitted into the hole 73, and has a length (length of the hole 73 + c) that is slightly longer than the thickness of the pressing member 70 (length of the hole 73). The slightly longer portion of this "slightly longer length" is the same as the gap c described below, and thus, when the bolt 75 is fully tightened, the gap c between the pressing member 70 and the inner lid portion 20 is reliably formed. A bolt 75 is inserted into the spacer 74 housed in the hole 73. Each bolt 75 is inserted into the spacer 74 and screwed into the bolt hole 25 of the inner lid portion 20. As a result, the bolt 75 is fixed to the inner lid portion 20 via the spacer 74, but the spacer 74 and the pressing member 70 are not fixed to each other. Therefore, when internal pressure is applied to the inner lid portion 20 from the valve chamber 11 side, the outer circumferential surface of the spacer 74 slides against the hole 73, and the inner lid portion 20 can move in a direction approaching the pressing member 70 by an amount that is slightly longer than the thickness of the pressing member 70. This kind of movement is possible, and a pressure seal, which will be described later, is realized.

The regulating portion 80 is a member that protrudes from the inner wall surface side of the valve chamber 11 toward the center and abuts against the pressing member 70 on the cylindrical portion 12 side. The regulating portion 80 fits into the groove 117 formed on the inner wall surface of the valve chamber 11, forming a convex portion that protrudes inward from the inner wall surface of the valve chamber 11 around the entire circumference. The regulating portion 80 is, for example, a member made of stainless steel. In this embodiment, the regulating portion 80 is formed by fitting a plurality of arc members 81 (for example, each of the four portions of the annular member) that have a shape obtained by dividing an annular member having an outer diameter that is approximately the same as the inner diameter at the bottom of the groove 117 in the valve chamber 11 into the groove 117. However, the structure of the regulating portion 80 is not limited to a structure using the arc members 81 of this configuration, and may be a structure that protrudes from the inner wall surface side of the valve chamber 11 by a method other than fitting. Thus, the outer periphery seal portion includes a seal member 60, a pressing member 70, and a restricting portion 80.

Furthermore, a wedge member 76 is disposed on the outer periphery of the pressing member 70. The wedge member 76 is an annular member having an inner diameter approximately equal to the outer diameter of the pressing member 70 at the step 72, and is fitted onto the step 72. The wedge member 76 has inner and outer periphery wall surfaces that are parallel to each other, a horizontal upper surface, and a bottom surface that is an inclined surface whose distance to the upper surface gradually decreases radially outward. Thus, when the wedge member 76 is fitted onto the pressing member 70 from above, it has a shape that moves an object that comes into contact with the bottom of the wedge member 76 toward the outer periphery. The upper surface of the wedge member 76 abuts against the head of a pressing bolt 77 that is fastened into a bolt hole on the upper surface of the pressing member 70. In this way, the pressing bolt 77 prevents the wedge member 76 from coming out upward. In this embodiment, the combination of the arc member 81, the wedge member 76, and the holding bolt 77 constitutes a restricting portion 80 that can reliably restrict the movement of the holding member 70 toward the cylindrical portion 12.

The pressing member 70 is fixed from above by bolts 75 to the outer peripheral edge of the upper surface of the inner lid portion 20 so that a slight gap can be created between the upper surface of the inner lid portion 20 and the lower surface of the pressing member 70. The "slight gap" referred to here is the gap indicated by "c" in FIG. 5, which is the gap between the main body 21 of the inner lid portion 20 and the surface of the step 72 of the pressing member 70 facing the valve chamber 11. This gap is maintained by the seal member 60 being sandwiched between the step 26 of the inner lid portion 20 and the convex ridge portion 71 of the pressing member 70. This "slight gap" (gap c) is a gap large enough to allow the aforementioned shaft seal to be established while still providing sufficient sealing performance from the pressure seal structure described below; for example, in the case of a 20-inch ball valve, it is about 1 to 2 mm.

In FIG. 5, two gaps c are provided, and these two gaps are set to the same width. The gaps are set so that the inner lid portion 20 and the pressing member 70 do not come into contact with each other when the initial squeezing of the inner lid portion 20 and the pressing member 70 described below is completed. Within the range set in this way, the width of the gaps c may be smaller than the value described above, or the widths of the two gaps c may be different.

On the other hand, the upper surface of the sealing member 60 abuts against the lower surface of the convex portion 22 of the pressing member 70, and thus the sealing member 60 is pre-pressed by the inner lid portion 20 and the pressing member 70 to an extent that the required initial compression amount of the sealing member 60 is obtained.

[Shaft seal structure]
7 is a schematic diagram showing another cross section of part D shown in FIG. 2. The "other cross section" here means a cross section having substantially the same configuration as part D shown in FIG. 2. The ball valve 1 has an axial seal structure for the stem 40 at the center of the inner lid part 20. The axial seal structure includes a seal material 91, a biasing member 92, and a pressing member 93. These members form a packing chamber between the stem 40 and the inner lid part 20, which is a cylindrical gap separated from the valve chamber. Above the packing chamber, a recess formed closer to the center than the protruding rib part 22 is formed as a gap that is larger than the packing chamber.

The seal material 91 is a substantially cylindrical member. The material of the seal material 91 is, for example, graphite or resin such as PCTFE and UHMW-PE. The seal material 91 has an inner diameter substantially the same as the outer diameter of the stem 40, and an outer diameter substantially the same as the inner diameter of the through hole in the center of the inner lid portion 20. The seal material 91 is disposed within the through hole (packing chamber), fits around the stem 40, fits inside the through hole, and fills the space between the stem 40 and the inner lid portion 20.

More specifically, the sealing material 91 is composed of a washer 911, a packing 912, and a packing retainer 913, from the ball valve body 30 side (lower side). All of these have an inner diameter that is approximately the same as the outer diameter of the stem 40, an outer diameter that is approximately the same as the inner diameter of the through hole in the center of the inner lid portion 20, and are fitted onto the stem 40 and into the through hole (packing chamber). The washer 911 is disposed at the bottom end of the packing chamber. The washer 911 is made of resin (e.g., PTFE). Multiple packings 912 are stacked and disposed on top of the washers 911. The packing retainer 913, also called the "gland," is disposed at the top of the packing chamber, above the topmost packing 912.

The biasing member 92 is housed in a recess formed on the inside of the convex rib portion 22 of the inner lid portion 20. The biasing member 92 biases the sealing material 91 from vertically upward to vertically downward so that the sealing material 91 is compressed in the vertical direction. The biasing member 92 is, for example, a disc spring. The inner peripheral edge of the biasing member 92 abuts against the upper surface of the packing retainer 913.

The pressing member 93 is a generally plate-like member having an annular shape, and covers the recess inside the convex rib portion 22 from above. The pressing member 93 has a number of through holes on its periphery. The through holes are located at positions overlapping with the bolt holes 24 of the convex rib portion 22. The pressing member 93 is fixed to the upper surface of the convex rib portion 22 by bolts 94 which screw into the bolt holes 24 through the through holes. Within the recess inside the convex rib portion 22, the biasing member 92 abuts against the pressing member 93 in the vertical direction in a position such that an appropriate biasing force is generated vertically downward. The packing presser 913 abutting against the biasing member 92 presses the packing 912 in the packing chamber under the pressing force of the biased biasing member 92. The packing 912 is compressed vertically and comes into contact with both the peripheral wall surface of the stem 40 and the inner peripheral wall surface of the through hole in the inner lid portion 20, sealing the periphery of the stem 40 while allowing the stem 40 to rotate.

[Assembly example]
The ball valve 1 is assembled, for example, as follows. The seat retainer 116 is installed inside the body 10. Next, the ball valve element 30 and the ball seat 115 are held as a unit and accommodated in the valve chamber 11 through the accommodation opening 113. Next, the stem 40 is connected to the ball valve element 30. These operations are performed from the outside of the body 10 through the upper end opening of the cylindrical portion 12, using a dedicated jig as necessary.

Then, the inner lid portion 20 is housed inside the body 10 while the stem 40 is inserted through the through hole in the center of the inner lid portion 20. The fitting portion 23 of the inner lid portion 20 fits into the housing opening 113, and the inner lid portion 20 is housed inside the body 10.

Then, the seal member 60 is introduced into the cylindrical portion 12 and fitted onto the step portion 26 of the inner lid portion 20. The seal member 60 is sandwiched between the inner lid portion 20 and the valve chamber portion 11.

Next, the pressing member 70 is placed. The spacer 74 may be inserted into the hole 73 of the pressing member 70 beforehand, or may be inserted after the pressing member 70 is placed. Then, the hole 73 of the pressing member 70 is aligned with the bolt hole 25 of the inner lid portion 20, and the bolt 75 is inserted into the spacer 74 and screwed into the bolt hole 25.

The bolt 75 is fastened to connect the pressing member 70 to the inner lid portion 20. The more the bolt 75 is fastened, the closer the pressing member 70 and the inner lid portion 20 are to each other, and the sealing member 60 is pressed by the inner lid portion 20 and the pressing member 70. The pressing member 70 and the inner lid portion 20 are not fixed to the valve chamber portion 11, so they are integrated by fastening the bolt 75 and are placed on the step of the accommodation opening of the valve chamber portion 11 and the ball valve body. In this state, the bolt 75 is fastened with the spacer 74 interposed, but the spacer 74 is stretched between the head of the bolt 75 and the inner lid portion 20, and the bolt 75 is fastened to a point where it becomes difficult to further tighten the bolt 75. Therefore, the fastening length of the bolt 75 is determined by the length of the spacer 74. Therefore, the sealing member 60 is compressed between the inner lid portion 20 and the pressing member 70, and the initial sealing properties required for the pressure seal structure described later can be expressed. This state also maintains the appropriate "slight gap c" between the inner lid portion 20 and the pressing member 70. Therefore, the tightening strength of the pressing member 70 against the inner lid portion 20 is uniform in the circumferential direction, and excessive tightening is prevented.

In the above state, the step 72 of the pressing member 70 faces the groove 117 that opens into the inner peripheral wall surface of the valve chamber 11, forming a gap between the step 72 and the inner peripheral wall surface. The bottom surface of the step 72 is located at approximately the same height as the lower side surface of the groove 117.

Then, the arc member 81 is dropped into the gap formed by the step 72. The arc member 81 has a cross-sectional shape in which the corners between the upper surface and the inner peripheral surface are cut away, and is bent with a curvature slightly larger than the circumference of the groove 117 when viewed in plan. When the four arc members 81 are lined up in the circumferential direction, the central portion in the longitudinal direction of the arc member 81 fits into the groove 117, and the ends protrude slightly from the groove 117 toward the center. During assembly, the inner lid portion 20 and the pressing member 70 are connected and integrated by tightening the bolts 75. This tightening adjusts the position of the inner lid portion 20 in the vertical direction by the pressing member 70 so that the upper surface of the pressing member 70, which is connected to the inner lid portion 20, just touches the lower surface of the arc member 81.

Next, the wedge member 76 is dropped and fitted into the step 72 of the clamping member 70. At that time, the portion of the arc member 81 that protrudes toward the step 72 abuts against the bottom surface of the wedge member 76 and is guided toward the outer periphery by its inclination. Then, the outer peripheral wall surface of the wedge member 76 abuts against the inner peripheral wall surface of the arc member 81, so that the entire circumferential direction of each arc member 81 is stored within the groove 117. In this way, a regulating portion 80 is formed that protrudes from the inner wall surface side of the valve chamber portion 11 toward the center. Next, the clamping bolt 77 is screwed into the bolt hole of the clamping member 70, and the head of the clamping bolt 77 abuts against the upper surface of the wedge member 76. The wedge member 76 prevents the arc member 81 from coming off the groove 117, and the clamping bolt 77 prevents the wedge member 76 from coming off the clamping member 70. Therefore, this configuration is advantageous in terms of preventing the restricting portion from falling off.

In this way, forming the regulating portion using the arc member 81 and the wedge member 76 is preferable from the viewpoint of more easily forming a convex structure that protrudes from the inner wall surface of the valve chamber portion 11 all around.

Then, the washer 911, packing 912, packing retainer 913, biasing member 92 and pressing member 93 constituting the sealing material 91 are fitted onto the stem 40 in this order and slid down to the center of the inner lid portion 20. The sealing material 91 is located between the inner peripheral wall surface of the through hole of the inner lid portion 20 and the outer peripheral wall surface of the stem 40 (packing chamber), the biasing member 92 (bellows spring) is located in a recess on the inside of the convex rib portion 22 of the inner lid portion 20, and the pressing member 93 is located on the upper surface of the convex rib portion 22. The hole of the pressing member 93 is aligned with the bolt hole 24 of the convex rib portion 22, and the bolt 94 is screwed into the bolt hole 24. In this way, the pressing member 93 is fixed to the upper surface of the convex rib portion 22 while biasing the biasing member 92.

Then, the body 10 is closed with the bonnet 50. In this way, the ball valve 1 as shown in FIG. 1 is assembled. In the ball valve 1 of this embodiment, which has the above-mentioned configuration and is constructed by the above-mentioned assembly method, the inner lid portion 20 and the pressing member 70, which are not fixed to the body 10, are connected with the sealing member 60 sandwiched between them to be approximately integrated. Then, while the sealing member 60 is initially crushed in this state, the rise of the integrated inner lid portion 20 and pressing member 70 is restricted by the restricting portion 80 (arc member 81). The ball valve 1 is characterized in these respects, and has a very advantageous structure in that a pressure seal structure can be easily formed even in a deep position at the bottom of the vertically long, cylindrical body 10 as in this embodiment.

[Sealing by peripheral seal part]
When the liquid flows and the internal pressure of the valve chamber 11 rises, a force is applied to the inner lid portion 20 in a direction pushing it upward. Since the inner lid portion 20 is not fixed to the valve chamber 11, it tries to move upward. This movement of the inner lid portion 20 also applies a force to the seal member 60 in a direction moving it upward. This force is also transmitted to the pressing member 70 via the seal member 60, and since the pressing member 70 is not fixed to the valve chamber 11, it also tries to move upward. However, the step 72 of the pressing member 70 comes into contact with the lower surface of the arc member 81. Therefore, the upward movement of the pressing member 70 is restricted. As a result, the seal member 60 is pressed upward from below by the bottom surface of the step portion 26 of the inner lid portion 20 due to the force of the inner lid portion 20 trying to move upward, and is sandwiched between the convex rib portion 71 of the pressing member 70, whose upward movement is restricted by the arc member 81. Furthermore, the sealing member 60 is pressed not only upward but also outward in the circumferential direction by the inclined bottom surface of the step portion 26. In this way, the sealing member 60 is compressed within the space surrounded by the step portion 26 of the inner lid portion 20, the convex ridge portion 71 of the pressing member 70, and the inner wall surface of the valve chamber portion 11. The higher the pressure that the inner lid portion 20 receives, the stronger the pressing force of the sealing member 60 by the inner lid portion 20, and the higher the sealing performance is. Therefore, pressure leakage from the outer circumferential edge portion of the inner lid portion 20 is prevented.

Here, the inner lid portion 20 and the pressing member 70 are connected so that they can move toward each other, but by fastening them with the bolt 75 with the sealing member 60 sandwiched between them, they are almost fixed in a state where they are separated by the above-mentioned "slight gap c" (initial state). In other words, the inner lid portion 20 and the pressing member 70 cannot be separated any further than this initial state, but can move toward each other by a maximum of the gap c. As a result, when upward pressure is applied to the inner lid portion 20, the sealing member 60 can theoretically be crushed by the amount of the gap c. If there was no gap between the inner lid portion 20 and the pressing member 70 and the two were in contact from the beginning, the inner lid portion 20 would not be able to move upward even if upward pressure was applied to the inner lid portion 20, so no pressure would be applied to the sealing member 60 and the sealing performance would not improve.

However, in reality, in the initial state, the sealing member 60 may be almost completely crushed, in which case it will be difficult to compress the sealing member 60 any further. Therefore, even if internal pressure from the valve chamber is applied to the inner lid portion 20, the inner lid portion 20 will not rise, and only the compressive force on the sealing member 60 will increase. As long as the gap between the inner lid portion 20 and the pressing member 70 is maintained, the compressive force on the sealing member 60 can continue to increase with the increase in internal pressure. As a result, the pressure seal by the outer periphery seal portion exhibits extremely excellent performance. In this way, the ability to reliably crush the initial state of the sealing member 60 (initial crushing) by connecting the inner lid portion 20 and the pressing member 70 can be a very advantageous point in the structure of this embodiment.

In this way, in this embodiment, the pressing member 70 is connected to the inner lid portion 20 but is not fixed to the body 10, and even within the body 10, it indirectly restricts the upward movement of the inner lid portion 20 but does not press the inner lid portion 20 downward. Furthermore, the pressing member 70 enables suitable initial squeezing of the seal member 60 between the inner lid portion 20. Therefore, a configuration that restricts the upward movement of the inner lid portion 20 and achieves an excellent peripheral seal can be constructed more easily than in the past.

In this way, the outer peripheral seal portion includes a pressure seal structure. This pressure seal structure further improves the sealing performance between the outer edge of the inner lid portion 20 and the inner wall surface of the valve chamber portion 11 as the pressure on the inner lid portion 20 from the valve chamber portion 11 side increases.

[Sealing by shaft seal structure]
With respect to the axial circumference of the stem 40, the biasing member 92, which exerts a specific biasing force by being fixed by the pressing member 93, presses the packing retainer 913 of the sealing material 91, thereby preventing pressure leakage near the peripheral surface of the stem 40. Thus, the axial circumference shaft seal structure of the stem 40 is a seal structure other than the pressure seal function in which the inner lid part 20 seals between the stem 40 and the through hole of the inner lid part 20 in the ball valve 1. More specifically, the shaft seal structure is a live load structure that includes a cylindrical sealing material 91 interposed between the inner peripheral surface of the through hole in the inner lid part 20 and the outer peripheral surface of the stem 40, and biases the sealing material 91 so as to maintain a substantially constant compressed state.

In general, when the inner lid portion 20 is subjected to fluid pressure under severe operating conditions such as high fluid pressure, extremely high or low temperature, or a larger ball valve 1, the inner lid portion 20 is likely to be deformed into a shape in which the center of the inner lid portion 20 rises, or the center of the inner lid portion 20 drops due to its own weight, resulting in distortion. If the shaft seal portion also has a pressure seal structure similar to that of the outer periphery seal portion, when upward pressure is applied to the inner lid portion 20 due to the internal pressure of the valve chamber, the sealing performance of the shaft seal portion is improved, just like the outer periphery seal portion, which may at first glance be considered preferable. However, as described above, in reality, it is difficult for the inner lid portion 20 to maintain a completely horizontal shape, so if either the outer periphery or the shaft pressure seal is effective first, the upward pressure is absorbed by it, and the other pressure seal cannot be effective, resulting in insufficient sealing performance in the other portion.

In contrast, in this embodiment, the axial seal structure of the stem 40 does not have a pressure seal structure due to the fluid pressure received by the inner lid portion 20, and is therefore suitable for achieving and maintaining sufficient sealing around the stem 40 regardless of whether the inner lid portion 20 is distorted.

The shaft seal structure is basically a seal structure suitable for sealing against the rotational movement of the stem shaft, and is often not suitable for the axial movement of the stem. Therefore, if the pressure seal causes the inner lid portion 20 to rise significantly, the seal by the shaft seal portion may be insufficient. In contrast, in this embodiment, the gap c caused by the connection between the inner lid portion 20 and the pressing member 70 is not actually intended to cause the inner lid portion 20 to rise, and therefore the gap c can be made smaller. In particular, by performing an initial crushing of the seal member 60, the inner lid portion 20 hardly rises. Therefore, the pressure seal structure as the outer periphery seal portion in this embodiment is suitable for maintaining the sealing properties of the shaft seal portion.

In addition, in the shaft seal structure, the packing chamber is separated from the valve chamber. Therefore, even if the position of the ball valve body 30 or stem 40 rises due to the pressure of the fluid flowing through the valve chamber, this does not affect the sealing provided by the packing 912.

In addition, in this embodiment, there is a possibility that the inner lid portion 20 may move in the vertical direction due to the pressure seal. However, in the shaft seal structure of this embodiment, the packing 912 in the independent packing chamber is always pressed with a constant force by a biasing member 92 (bellows spring) whose upper part is fixed by a pressing member 93 that moves up and down accompanying the inner lid portion 20. Therefore, the sealing performance of the packing 912 is not affected by the vertical position and movement of the inner lid portion 20. Therefore, even if the inner lid portion 20 is deformed (for example, the central region bulges) due to fluid pressure or the like, the shaft seal structure of this embodiment can independently exert a constant sealing performance only in that part.

Furthermore, because the washer 911 is made of resin, the washer 911 tends to shrink toward the inner diameter under extremely low temperature conditions. By using such a washer 911, the packing 912 is prevented from dropping (being pulled in) toward the valve chamber. A metal washer is normally used for the washer 911, but if a metal washer is used, the shrunken washer 911 may interfere with the rotational movement of the stem 40, damaging the stem 40 or causing an increase in the operating torque of the stem 40. By using a resin washer 911, the above concerns are essentially eliminated.

The ball valve 1 has a structure that is sufficiently durable for use under harsh operating conditions. Therefore, the ball valve 1 is suitable as a valve for extremely low temperature fluids such as liquid hydrogen. In addition, because it is a ball valve 1, it is suitable as a valve for large flow rates of fluids.

[Modifications]
The shaft seal structure may be a seal structure other than the live load structure.

The ball valve of the present invention is suitable for relatively large-diameter ball valves with a flow passage opening diameter of 10 inches or more, but can also be applied to valves with smaller diameters.

In the present invention, the movement of the pressing member toward the cylindrical portion may be restricted by a configuration other than the restricting portion. For example, the movement of the pressing member toward the cylindrical portion may be restricted by screwing the pressing member along the axial direction of the valve chamber using a threaded portion formed on the outer circumferential surface of the pressing member and a portion of the inner wall surface of the valve chamber facing the outer circumferential surface. Alternatively, the movement of the pressing member toward the cylindrical portion may be restricted by engaging a member such as a bolt that can advance into the unevenness of the inner wall surface of the valve chamber with the unevenness. Alternatively, the movement of the pressing member toward the cylindrical portion may be restricted by arranging a rod-shaped member extending in the axial direction of the cylindrical portion between the pressing member and the bonnet so that it is tensioned.

〔summary〕
As is clear from the above description, the ball valve (1) of the first embodiment of the present invention has two or more flow passage openings (111, 112) which serve as flow passages for a fluid and a storage opening (113) through which a ball valve body can pass, and has a valve chamber (11) in which a ball valve body (30) is stored so as to be rotatable and capable of opening and closing the flow passage opening, a cylindrical portion (12) connected to the valve chamber by the storage opening, an inner lid portion (20) which closes the storage opening of the valve chamber and separates the valve chamber from the cylindrical portion at one end side of the cylindrical portion, a bonnet (50) which closes the opening on the other end side of the cylindrical portion, a rotatable stem (40) which penetrates the bonnet and the inner lid portion and is connected to the ball valve body, and an outer circumferential seal portion having a pressure seal structure in which the sealing property between the outer edge of the inner lid portion and the inner wall surface of the valve chamber increases as the pressure on the inner lid portion from the valve chamber side increases. The outer circumferential seal portion includes a seal member (60) that is accommodated in a gap between the outer edge of the inner lid portion and the inner wall surface of the valve chamber, and a pressing member (70) that overlaps the inner lid portion from the cylindrical portion side, is connected to the inner lid portion with a gap between them so that it can move toward and away from the inner lid portion, and sandwiches the seal member between the outer edge of the inner lid portion and the inner wall surface of the valve chamber. Movement of the pressing member toward the cylindrical portion is restricted by a restricting portion (80) that protrudes from the inner wall surface side of the valve chamber toward the center and abuts against the pressing member on the cylindrical portion side. According to the first aspect, a ball valve in which the valve chamber can be sufficiently sealed against the cylindrical portion can be realized even for a large-diameter ball valve.

The second aspect of the ball valve of the present invention is the first aspect, in which the inner lid portion further comprises an axial seal structure other than a pressure seal structure that seals between the stem and the through hole in the inner lid portion. The second aspect is even more effective in terms of achieving and maintaining sufficient sealing around the stem regardless of the presence or absence of distortion in the inner lid portion.

The ball valve of the third aspect of the present invention is a live-loaded structure in which the shaft seal structure is provided with a cylindrical seal material (91) interposed between the inner circumferential surface of the through hole in the middle lid portion and the outer circumferential surface of the stem, and the seal material is biased so as to maintain a substantially constant compressed state. The third aspect is even more effective in terms of achieving and maintaining sufficient sealing performance around the stem.

The fourth aspect of the ball valve of the present invention is any of the first to third aspects, in which the pressing member has a further gap between it and the restricting portion in the protruding direction of the restricting portion, and the restricting portion includes a portion whose outer periphery is inserted into a groove (117) provided around the inner wall surface of the valve chamber, and a portion that protrudes from the inner wall surface in this state, and further includes a wedge member (74) that is inserted into the further gap and abuts against both the pressing member and the restricting portion, maintaining the restricting portion inserted into the groove. The fourth aspect is even more effective in terms of preventing the restricting portion from falling off.

The fifth aspect of the present invention is a ball valve that is the fourth aspect, but further includes a fixing member (pressing bolt 77) that abuts against the wedge member from the cylindrical portion side and is fixed to the pressing member. The fifth aspect is even more effective from the viewpoint of easily forming a restricting portion that protrudes from the inner wall surface of the valve chamber over the entire circumference.

The sixth aspect of the ball valve of the present invention is any one of the first to fifth aspects, in which the retaining member has a through hole (hole 73) through which the bolt (75) is inserted, and a tubular spacer (74) having a length equal to or greater than the thickness of the retaining member, inserted into the through hole and through which the bolt is further inserted, and the bolt is inserted in an untightened state through the spacer inserted into the through hole of the retaining member, and the tip of the bolt is fastened and fixed into a female threaded hole (bolt hole 25) provided in the inner lid portion, supporting the spacer in a state of tension between the head of the bolt and the inner lid portion. The sixth aspect is even more effective in terms of fixing the retaining member to the inner lid portion with appropriate and uniform strength in the circumferential direction.

The seventh aspect of the present invention is a ball valve in which the diameter of the flow passage opening is greater than 10 inches in any of the first to sixth aspects. The seventh aspect is advantageous in that the sealing effect of the peripheral seal portion is further enhanced.

With the above configuration, the valve chamber of the ball valve can be adequately sealed against the cylindrical body, even in the case of a large-diameter ball valve. This makes it suitable for handling large flow rates of fluids that require harsh operating conditions, such as cryogenic fluids like liquid hydrogen. 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) advocated 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 valve 10 body 11 valve chamber 12 cylindrical portion 20 inner lid portion 21

main body portion

22, 71 convex rib portion 23

fitting portion

24, 25 bolt hole 26 step portion 30 ball valve body 31 through hole 32 convex portion 40 stem 50 bonnet 60

seal member

70, 93 pressing member 72 step 73 hole 74

spacer

75, 94 bolt 76 wedge member 77 pressing bolt 80 restricting portion 81 arc member 91 seal material 92 biasing member 111 first flow passage opening 112 second flow passage opening 113 accommodation opening 114 recess 115 ball seat 116 seat retainer 117 recess 911 washer 912 packing 913 Packing retainer

Claims

a valve chamber having two or more flow passage openings which serve as flow passages for a fluid and an accommodation opening through which a ball valve body can pass, the ball valve body being accommodated in the valve chamber so as to be rotatable and to open and close the flow passage openings;
a cylindrical portion connected to the valve chamber portion at the accommodation opening;
an inner lid portion that closes the accommodation opening of the valve chamber portion and separates the valve chamber portion from the cylindrical portion at one end side of the cylindrical portion;
a bonnet for closing an opening at the other end of the cylindrical portion;
a rotatable stem that penetrates the bonnet and the inner lid portion and is connected to the ball valve body;
an outer circumferential seal portion having a pressure seal structure in which the sealability between the outer edge of the inner lid portion and the inner wall surface of the valve chamber increases as the pressure on the inner lid portion from the valve chamber side increases,
The outer circumferential seal portion is
a seal member that is accommodated in a gap between an outer edge of the inner lid portion and an inner wall surface of the valve chamber;
a pressing member that overlaps the inner lid portion from the cylindrical portion side, has a gap between itself and the inner lid portion, is connected to the inner lid portion so as to be movable toward and away from the inner lid portion, and sandwiches the seal member between an outer edge of the inner lid portion and an inner wall surface of the valve chamber, and is restricted in its movement toward the cylindrical portion side.
Ball valve.
The ball valve according to claim 1, further comprising a restricting portion that protrudes from the inner wall surface side of the valve chamber toward the center and abuts against the pressing member on the cylindrical portion side, restricting the movement of the pressing member toward the cylindrical portion side.
The ball valve of claim 1, wherein the inner lid portion further comprises an axial seal structure other than a pressure seal structure that seals between the stem and the through hole of the inner lid portion.
The ball valve according to claim 3, wherein the shaft seal structure is a live-load structure that includes a cylindrical seal material interposed between the inner circumferential surface of the through hole in the middle lid portion and the outer circumferential surface of the stem, and is biased so that the seal material can maintain a substantially constant compressed state.
the pressing member has a further gap between itself and the restricting portion in a protruding direction of the restricting portion,
the restricting portion includes a portion the outer circumferential side of which is inserted into a groove formed around the inner wall surface of the valve chamber, and a portion which protrudes from the inner wall surface in this state,
3. The ball valve according to claim 2, further comprising a wedge member that is inserted into the further gap to abut against both the pressing member and the restricting portion and maintains an inserted state of the restricting portion in the groove.
The ball valve according to claim 5, further comprising a fixing member that abuts against the wedge member from the cylindrical portion side and is fixed to the pressing member.
the pressing member has a through hole through which the bolt is inserted, and a tubular spacer having a length equal to or greater than a thickness of the pressing member, inserted into the through hole, and through which the bolt is further inserted,
2. The ball valve according to claim 1, wherein the bolt is inserted in an untightened state through the spacer inserted into the through hole of the retaining member, and the tip of the bolt is fastened and fixed into a female threaded hole provided in the inner lid portion, so that the spacer is supported in a tensioned state between the head of the bolt and the inner lid portion.
The ball valve of claim 1, wherein the flow passage opening has a diameter greater than 10 inches.