TW201638509A - Trunnion-type ball valve - Google Patents

Abstract

A seat retainer (14) fitted with a ball seat (15) is provided on one or both sides of a ball (12) having a through hole (12a) provided inside a body (11), the ball (12) is provided so as to be rotatable by a stem (13), and the ball seat (15) is prevented from flying out into a fitting groove (32) formed in the seat retainer (14), and is fitted in a free state. Excess pressure due to abnormal pressure increases in a cavity (35) when fully open or fully closed causes the seat retainer (14) to move in an opposite direction from the ball (12) due to a self-sealing force making use of this pressure, and excess pressure that has flowed to the rear surface side of the ball seat (15) inside the fitting groove (32) pushes the ball seat (15) toward the ball (12), and is relieved to a flow channel via a communication part (40) provided between the inner circumferential surface (27) of the ball seat (15) and the fitting groove (32).

Description

Trunnion type ball valve

The present invention relates to a trunnion type ball valve, and more particularly to a mounting structure of a ball seat and a seat holder which can exhibit high sealing properties for a high-pressure fluid.

A trunnion type ball valve, particularly a valve structure suitable for a high-pressure fluid, generally, a ball seat that becomes a valve seat is mounted on a valve body while being held in a seat holder, the ball seat is by a coil spring The elastic force is ejected toward the valve body, and the fluid is sealed by the primary side (upstream side) ball seat by pushing the ball seat.

In this case, the ball seat and the seat holder are configured to prevent the ball seat from coming off the seat holder. For example, in the ball valve of Patent Document 1, the female thread is provided in the seat, and the male thread is provided in the seal ring. Through these female threads and male threads, the sealing ring is mounted to the seat. A disc spring is mounted in the back of the seat, whereby the disc spring and the seal ring are urged toward the valve body. Therefore, the seal ring is pressed against the valve body by the compression coil spring attached to the back side in a state in which the end portions of the spiral peaks are brought into contact with each other to prevent loosening from the seat. Contact between the seal ring and the valve body The surface forms a gap.

Further, in the ball valve, a sealing member is provided on the inner diameter side of the seal ring, whereby the pressure member is prevented from infiltrating on the back side by the sealing member, and the pressure leakage due to the discharge of the seal ring caused by the negative pressure is prevented. The back of the seal ring.

In the ball valve of Patent Document 2, a zigzag-like uneven portion is formed in the seal gasket, and the seat gasket is joined to the seal gasket by allowing the gasket to enter the zigzag-shaped uneven portion. In this state, the seat gasket is fixed in a state in which the back surface is pressed into the sealing gasket, thereby preventing the occurrence of the sag caused by the negative pressure of the fluid pressure. Further, by the press-in of the seat gasket toward the sealing gasket, leakage from the back of the seat gasket is also prevented.

In the ball valve of Patent Document 3, a valve seat holding ring is engaged with the outer circumference of the valve seat back side, and a circumferential fluid communication groove is provided on the engagement surface of the valve seat holding ring. By passing through the fluid communication hole from the fluid communication groove, the pressure difference between the inlet side flow path portion pressure and the pocket portion pressure is made equal, and the valve seat is pulled back to the normal position. Thereby, the valve seat is prevented from being thrown, deformed, or damaged.

On the other hand, in the ball valve 1 shown in Fig. 14, the detachment from the seat holder 2 to the ball seat 3 is prevented, and the ball seat 3 is in a state where the seat holder 2 is free. The structure that is installed.

Further, in such a ball valve, in addition to the prevention of the fall of the ball seat, the ball seat and the valve body are required to maintain a high sealing property and can be opened and closed. For example, in the ball valve of Patent Document 1, in addition to the above-described prevention of the sealing of the seal ring, in order to ensure the sealing property, the sealing surface of the ball seat is set to be sealed with the valve body. The same curvature is used, and the spherical seats of the same curvature and the sealing faces of the valve body are in close contact with each other across the entire circumference.

In the same manner as in Patent Document 1, the ball valve in the range of the sealing valve 6 formed in the range from the primary side seal portion 4 to the secondary side seal portion 5 of the ball seat 3 is provided to the outer periphery of the ball valve body 7. The valve body sealing surface 8 has the same curvature.

That is, in these ball valves, in FIG. 14, the ball seat 3 is prevented from falling off, and the spherical shape of the ball valve body 7 and the sealing surface 6 of the ball seat 3 are the same size, from low pressure to high pressure. At this time, the fluid pressure is sealed in a state in which the sealing surface 6 is in a state in which the sealing surface 6 is in contact with the valve body sealing surface 8 in a range from the primary side sealing portion 4 to the secondary side sealing portion 5.

Patent Document 4 discloses that the ball seat is held in the seat holding portion in a state of being rotatable in the circumferential direction, and the ball valve that prevents the partial wear of the ball seat from being lowered in the sealing direction by the rotation of the ball in the circumferential direction is prevented. .

In the ball valve of Patent Document 5, the space on the bottom surface of the seat ring and the bottom surface of the seat ring holding groove of the seat holding means is such that the outer diameter becomes wider toward the ball side, and the pressing deformation when the seat ring is pressed is By the space being absorbed, the positional change of the sealing portion is prevented to maintain the sealing property.

In each of the above-described trunnion type ball valves, a resin material is generally used for the ball seat. In this case, when the fluid pressure becomes high, the ball seat seals the fluid while elastically deforming under pressure.

[Practical Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 9-133225

[Patent Document 2] Japanese Unexamined Patent Publication No. 2-124377

[Patent Document 3] Japanese New Type 2577156

[Patent Document 4] Japanese Patent No. 3815669

[Patent Document 5] Japanese Patent No. 48112091

In the ball valve of Patent Document 1, in order to prevent the ball seat from falling off from the seat holder, the ball valve has a number of parts and points in addition to the seal ring and the seat, since the disk spring, the compression coil spring, and the sealing member are provided. The structure is also complicated. Since the sealing member is disposed on the inner diameter side of the seal ring and the compression coil spring is provided on the back side of the seal ring, the assemblability is also poor. In this case, since the groove and the recess for the component mounting are mostly formed in the seal ring, the rigidity of the entire seal ring is liable to be lowered, and in order to eliminate this, it is necessary to use a high-strength material for the seal ring material.

Further, in this ball valve, the release of the case where the abnormal pressure rise occurs in the groove is not considered, and the ball seat is a structure in which the coil spring is bounced, and when the abnormal pressure rise occurs in the groove, because The ball seat moves toward the primary side together with the seat holder and releases the pressure from between the seat and the valve body, so that the contact surface between the seat and the valve body is intensively worn. As a result, the sealing point is unstable and the release pressure is uneven. When released, because it is the way to open the contact of the seat The pressure is released, so there is also the problem that the contact surface is easily broken.

In the ball valve of Patent Document 2, it is also tried to prevent the seat gasket from being thrown out, but since the seat gasket is pressed into the sealing gasket and integrated, the seat gasket becomes high temperature, and has a seal from the sealing gasket. The possibility of throwing out. This seat gasket has a structure in which the leakage preventing structure is provided with a tapered surface in the vicinity of the back surface, and the size of the sealing gasket and the seat gasket is also difficult because the wedge effect is integrated with the sealing gasket. Further, when the seat gasket is pressed into the sealing gasket by the uneven structure, the assembly work becomes difficult. For example, when the seat gasket is not deformed according to a predetermined state, the seat gasket cannot be assembled during assembly and when the valve is actuated. It is stored in a predetermined position of the gasket and has a possibility of partial wear. In order to prevent this, it is also necessary to perform the seating surface processing after pressing.

Moreover, there is also a problem that the seat gasket is easily consumed by the release of the abnormal pressure rise in the groove.

In the ball valve of Patent Document 3, the pressure difference is reduced through the fluid communication groove and the fluid communication hole during the rotation of the valve body, and the valve seat is prevented from being ejected and deformed, but the abnormal pressure rise in the groove is not considered. .

In the ball valve of the structures of the above-described Patent Documents 1 and 14, the high pressure is applied from the flow path side in the state after assembly and at the time of low pressure, and the resin ball seat 3 is indicated by the arrow in Fig. 15 The abutting portion 9 with the seat holder 2 is elastically deformed in a direction in which the center is expanded outward. When the ball seat 3 is elastically deformed, since the abutting portion 9 is located closer to the outer diameter side than the primary side seal portion 4 in FIG. 14, the primary side seal portion 4 is centered on the abutting portion 9 The outer side of the tee 3 is expanded by the rotation Moves in the direction approaching the ball valve body 7. As a result, as shown in Fig. 15, the sealing of the ball valve body 7 and the ball seat 3 is a line contact from the primary side seal portion 4 to the secondary side seal portion 5 to the line contact on the side of the primary side seal portion 4, The sealing by the line contact causes the sealing surface pressure of the primary side seal portion 4 to locally rise, and the ball seat 3 may be partially deformed. When the valve is rotated in this state, the primary side seal portion 4 cannot withstand the surface pressure and causes partial wear, which causes the fluid to easily leak.

Further, in the fifteenth figure, the ball seat 3 is rotated by the abutting portion 9 as a base point, and the primary side seal portion 4 serving as the seal portion is positioned closer to the ball valve body 7 than the second side seal portion 5. The sealing of the ball valve body 7 by the secondary side seal portion 5 becomes difficult, and the avoidance of the increase in the local surface pressure generated by the primary side seal portion 4 becomes difficult. This phenomenon is more remarkable as the valve becomes larger in diameter, and the sealing performance at the time of high pressure is remarkably lowered to ensure the sealing performance from low pressure to high pressure.

In Patent Document 4, it is possible to prevent the detachment of the ball seat and to prevent the eccentric wear caused by the rotation in the circumferential direction. In Patent Document 5, the detachment of the ball seat is prevented, and the pressing deformation of the seat ring is absorbed to prevent it. The change in the position of the seal. However, in any of the cases, when the fluid is at a high pressure, the ball seat is elastically deformed in the expanding direction as in the ball valve of Fig. 14, so that the contact with the ball valve body changes from the surface contact to the near-line contact, and the seal is sealed. The surface has a partial wear and has the possibility of a drop in sealing performance.

The present invention has been made in order to solve the conventional problems, and an object thereof is to provide an trunnion type ball valve that prevents the ball seat from being detached from the seat holder. In the case of the high pressure, the ball seat and the valve body can be improved at the time of high pressure, while avoiding the increase in the number of points and suppressing the increase in the number of parts, while ensuring the strength and improving the workability and the assemblability. The sealability prevents leakage and improves the durability of the tee.

In order to achieve the above object, the invention of claim 1 is an trunnion type ball valve in which one or both of the balls having the through holes provided in the valve body are disposed in the seat holder on which the ball seat is mounted. The ball is rotatably disposed through the rod, and the ball seat is a ball valve that is prevented from being ejected into the installation groove formed in the seat holder and is installed in a free state, and the ball valve is to be fully closed or The excess pressure generated by the abnormal pressure rise in the groove at the time of full opening is caused by the self-tightening force using the pressure to move the seat holder in the opposite direction to the ball, and the back side of the ball seat which flows into the installation groove The excess pressure pushes the ball seat toward the ball side and releases it into the flow path through the communication portion provided between the inner circumferential surface of the ball seat and the installation groove.

According to the second aspect of the invention, in the engagement portion provided on the opening side of the inner circumference of the installation groove, the locking portion provided on the outer circumferential mounting side of the ball seat is releasably facing in the loading direction. Therefore, the ball seat is prevented from being thrown out from the mounting groove of the seat holder, and the ball seat is installed in the installation groove in a free state.

According to the invention of claim 3, the female screw portion provided on the inner circumference of the installation groove is used as an engagement portion, and the male screw portion of the ball seat is screwed to the female screw portion as the locking portion, and the male screw portion is used. The rear end side and the rear end side of the female screw portion are provided to be lockable to prevent the ball seat from being thrown out.

According to the invention of claim 4, the screw peak of the inner end of the female screw portion and the peak of the outer end of the male screw portion are locked to prevent the ball seat from being thrown out.

According to the invention of claim 5, at least one of the release grooves constituting the communication portion is formed on the inner circumferential surface of the ball seat or the installation groove of the seat holder facing the inner circumferential surface.

According to the invention of claim 6, the fulcrum position of the back surface of the ball seat is set to be the inner diameter of the portion A to be larger than the sealing portion of the ball seat, and the ball seat at the high pressure is the fulcrum of the portion A. In an enlarged manner, the elastic deformation seals the sealing portion from the outer diameter side toward the inner diameter side at least in a surface contact state.

According to the invention of claim 7, the positional relationship between the fulcrum position, that is, the A portion and the sealing portion, that is, the sealing portion B and the sealing portion C is set to A < C < B for the inner diameter dimension.

The invention of claim 8 is a case where the initial stage of assembly and the fluid pressure are low pressure, the sealing portion B is in a state in which the wire is in contact, and the sealing portion C is in a non-contact state with the spherical surface.

According to the ninth aspect of the invention, the sealing portion of the ball seat is formed into a spherical surface, and the spherical surface is disposed on the flow axis of the valve body in the same manner as the center of the ball, and Its inner diameter is formed smaller than the spherical shape of the ball.

According to the invention of claim 10, a predetermined play is provided between the inner circumferential surface of the installation groove and the outer circumferential surface of the sealing surface side of the ball seat, and the spherical seat is enlarged at the time of high pressure, and excessive expansion is suppressed.

The invention of claim 11 is formed in the A clearance is provided between the inner circumferential surface of the locking portion where the groove is provided and the outer circumferential surface side of the spherical seat.

According to the invention of the first aspect of the patent application, it is possible to prevent the ball seat from being mounted in such a manner as to be thrown into the installation groove of the seat holder, and the case where the high-pressure fluid flows and the case where the valve is slightly opened can also prevent the ball seat. Shedding and high sealing. The ball seat is mounted on the seat holder in a free state, and the abnormal pressure rise occurs when the ball is fully closed or fully opened. By using the pressure in the groove, the seat holder is directed toward the ball by the self-tightening force. The opposite direction is moved, and the excess pressure generated by the abnormal pressure increase in the groove is released into the flow path through the communication portion between the inner circumferential surface of the ball seat and the installation groove, and the excess pressure is generated by the abnormal pressure increase. When the pressure is released, the wear of the contact surface between the ball seat and the ball can be prevented. Therefore, the release point at the time of closing the valve can be stabilized and the abnormal pressure rise can be surely avoided, and the high sealing property can be maintained even when the valve is closed, and the high-pressure fluid can be prevented from leaking out. Further, by forming the release mechanism by the ball seat and the seat holder, it is possible to suppress the increase in the number of parts and to simplify the internal structure, and to secure the ball seat without increasing the groove and the recess, and the workability and assembly property are also improved. Can be improved.

According to the invention of claim 2, the ball seat is movable to the seat holder when the ball seat is mounted in the mounting groove of the seat holder in a free state, and the force is applied to the ball seat. The fluid between the back side of the ball seat and the seat holder flows toward the secondary side, and the facing portion of the engaging portion and the locking portion prevent the ball seat from being thrown out.

According to the invention of claim 3, The female screw portion is used as the engaging portion, and the male screw portion is used as the locking portion, and these are provided in the loading direction, and the ball holder can be easily attached to the seat holder by the screwing. After the closing, the rear end side of the male screw portion facing each other and the rear end side of the female screw portion are locked, so that the ball seat can be surely prevented from being thrown out.

According to the invention of the fourth aspect of the patent application, while the ball seat and the seat holder are prevented from being re-threaded, the free state of the ball seat is maintained, and the locking of the screw peaks is surely prevented from being thrown out of the ball seat. Moreover, the screw peak can be easily formed without complicated processing at the time of production, and assembly is also simple.

According to the invention of claim 5, the groove and the flow path side are made connectable by the release groove, and the seat holder and the ball seat are moved in opposite directions by the self-tightening force, and the seat back side is supported by the seat holder. When separating, the pressure in the groove is discharged through the release groove, and the abnormal pressure rise can be eliminated.

According to the invention of claim 6 of the present invention, when the ball seat is prevented from falling off from the seat holder and the ball seat is installed in a free state in the installation groove, the ball seat is when the fluid pressure is low. The outer diameter side of the sealing portion is in contact with the ball line, and in the case of high pressure, the deformation is elastically deformed such that the portion A is fulcrum, so that the sealing portion is sealed with the ball in the surface contact state, and when the large-diameter valve high-pressure fluid flows, It is also possible to improve the sealing property of the ball seat and the valve body to reliably prevent leakage. It is possible to prevent the contact of the sealing portion toward the ball to be minimally suppressed and sealed, and at the low pressure, the inner diameter side of the sealing portion is prevented from being ground by the rotation of the ball and the partial surface of the sealing portion can be prevented. The occurrence of pressure can also prevent the wear of the tee and improve the durability.

According to the invention of claim 7, when the fluid pressure is a low pressure, the fulcrum position, that is, the A portion is in a state in which the back portion is sealed, and the sealing portion B is prevented from coming into contact with the ball while the sealing portion B is in contact with the ball. The wire contact seal produced by the sealing portion B prevents the ball seat from being worn and prevents leakage. When the fluid pressure is high, the spherical seat is elastically deformed in the direction in which the ball is enlarged, centering on the portion A of the fulcrum position, and the sealing portion B on the outer diameter side is brought into contact by bringing the sealing portion C side into contact with the ball. When the vicinity of the seal portion C on the radial side is in contact with the ground as a sealing portion, it is possible to prevent the occurrence of partial surface pressure and prevent partial wear of the sealed portion, and to improve the sealing property and reliably prevent leakage.

According to the invention of claim 8 of the patent application, when the fluid pressure is at a low pressure, the sealing portion B can be prevented from coming into contact with the ball and excessive wear can be suppressed, and the sealing property against leakage of the fluid can be ensured.

According to the invention of the ninth aspect of the invention, when the fluid pressure is high, the ball seat is elastically deformed so that the ball seat is enlarged, and the spherical surface of the seal portion is brought into contact with the outer peripheral surface of the ball to prevent it. The partial wear of the sealing portion and the improvement of the sealing property.

According to the invention of claim 10, it is possible to elastically deform toward the play side and maintain a high sealing property without suppressing the deformation of the ball seat at a high pressure, and to avoid the installation of the groove by the ball seat. The excess stress generated by the contact is transmitted to maintain its softness. On the other hand, by preventing the ball seat from being excessively enlarged by the clearance, it is possible to prevent the leakage of the surface contact at the time of high pressure.

According to the invention of the eleventh aspect of the patent application, the ball seat can be installed in a free state while being prevented from being pulled out from the seat holder, so that the ball can be sealed from the low pressure to the high pressure. Elastic deformation.

Part A ‧ ‧ fulcrum position

B, C‧‧‧ Sealing Department

CL‧‧‧ clearance

L1, L2, L3‧‧‧ inner diameter size

O‧‧‧Flow center axis (flow axis)

1‧‧‧Ball valve

2‧‧‧ holders

3‧‧‧ tee

4‧‧‧Primary seal

5‧‧‧Secondary side seal

6‧‧‧ sealing surface

7‧‧‧Ball valve body

8‧‧‧ valve body sealing surface

9‧‧‧Apartment

10‧‧‧ valve body

11‧‧‧ valve body

12 ‧ ‧ ball

12a‧‧‧through hole

13‧‧‧ great

13a‧‧‧上棒

13b‧‧‧下棒

14‧‧‧ holders

15‧‧‧ tee

15a‧‧‧Back

15b‧‧‧ sloped surface

15c‧‧‧ outer perimeter

16‧‧‧ spherical

20‧‧‧Circular valve body

21‧‧‧ Cap

22‧‧‧Bolt nuts

23‧‧‧Flow

25‧‧‧ sealing surface (sealing part)

27‧‧‧ inner circumference

30‧‧‧ Male threaded part (locking part)

30a‧‧‧Spiral peak

31‧‧‧ release ditch

32‧‧‧Installation ditch

32a‧‧‧ inner circumference

33‧‧‧Female thread part (engagement part)

33a‧‧‧Spiral peak

33b‧‧ ‧ parallel faces

34‧‧‧ bottom hole

35‧‧‧ Groove

40‧‧‧Connecting Department

41‧‧‧ coil spring

42‧‧‧O-ring

43‧‧‧ Seal

45‧‧‧ annular protrusion

50‧‧‧ gap

51‧‧‧ring edge

52‧‧‧ annular protrusion

60‧‧‧Care Department

61‧‧‧Cards

Fig. 1 is a longitudinal sectional view showing a first embodiment of the trunnion type ball valve of the present invention.

[Fig. 2] An enlarged cross-sectional view of the F-F in Fig. 1 .

[Fig. 3] A cross-sectional view taken along line J-J in Fig. 1.

[Fig. 4] A longitudinal sectional view showing the assembly work of the ball seat.

[Fig. 5] A partially enlarged cross-sectional view showing a state in which an abnormal boost occurs.

[Fig. 6] A partially enlarged cross-sectional view showing a state in which the ball seat of Fig. 5 is moved.

[Fig. 7] A partially enlarged cross-sectional view showing a slightly opened state of the ball in the field E of Fig. 3.

[Fig. 8] Fig. 8 is an enlarged cross-sectional view showing the main part of a second embodiment of the trunnion type ball valve of the present invention.

[Fig. 9] An enlarged cross-sectional view showing the main part of a third embodiment of the trunnion type ball valve of the present invention.

[Fig. 10] A perspective view showing a main part of a fourth embodiment of the trunnion type ball valve of the present invention.

[Fig. 11] A partially enlarged longitudinal sectional view showing a fifth embodiment of the trunnion type ball valve of the present invention.

[12] Fig. 12 is an enlarged cross-sectional view showing a state in which the ball seat of Fig. 11 is sealed.

[Fig. 13] A partially omitted enlarged cross-sectional view showing the relationship between the ball and the tee.

[Fig. 14] A cross-sectional view showing a main portion in the vicinity of a primary side portion of a conventional trunnion type ball valve.

[Fig. 15] A cross-sectional view showing a main part of a state in which the ball seat of Fig. 14 is sealed.

Hereinafter, an embodiment of the trunnion type ball valve in the present invention will be described based on the drawings. In Fig. 1, an embodiment of the trunnion type ball valve of the present invention is shown in a state in which the valve is opened, and in Fig. 3, a sectional view of JJ in Fig. 1, that is, the trunnion type ball valve of the present invention is shown. Central cross section view.

The trunnion type ball valve of the first embodiment (hereinafter referred to as the valve body 10) has a valve body 11, a ball 12, a rod 13, a seat holder 14, and a ball seat 15, and is particularly suitable for a large diameter and used for grades ( Nominal pressure) When the high pressure fluid is about 150 to 2500.

The valve body 11 is an annular valve body 20 and annular caps 21 and 21 on both sides. These are formed of carbon steel, stainless steel or the like, and are integrated by the bolt nut 22.

In the valve body 11, through the upper rod 13a, the lower rod 13b The rod 13 is rotatably provided to the ball 12, and a seat holder 14 is disposed on both sides of the ball 12, that is, on the up and down side, and the ball seat 15 is mounted on the seat holder 14. The ball 12 is formed of stainless steel as a material, and is provided with a through hole 12a that can communicate with the flow path 23 in the valve body 10. In the present embodiment, the ball seat 15 and the seat holder 14 are attached to the upstream side of the ball 12, but these may be provided on one or both of the upstream and downstream sides. As shown in Fig. 1, in the case where the ball seat body 10 of the ball seat 15 and the seat holder 14 is attached to the upstream side, the side of either the right side or the left side in the figure may be the primary side.

The ball seat 15 is formed of an elastically deformable ring shape by a resin material such as PTFE (polytetrafluoroethylene) and nylon or PEEK (polyether ether ketone), and a sealing surface 25 is provided in the abutting side of the ball 12. The annular inner peripheral surface 27 and the sealing surface 25 are continuously provided to the side of the back surface 15a of the ball seat 15.

The male screw portion 30 is provided on the side of the seat holder 14 which is provided on the outer circumference of the ball seat 15 as a locking portion. The male screw portion 30 has a length which is approximately half the thickness of the ball seat 15 in the mounting direction.

In FIGS. 3 and 4, at least one release groove 31 is formed on the inner peripheral surface 27 of the ball seat 15. The release groove 31 is provided at a predetermined depth from the vicinity of the boundary between the inner peripheral surface 27 and the sealing surface 25 to the side of the back surface 15a of the ball seat 15, and the release groove 31 can be formed in the seat holder 14 The communication portion 40 between the inner peripheral surface 27 side and the outer peripheral surface side (the male screw portion 30 side) of the ball seat 15 after installation. The release groove 31 is preferably provided at a plurality of locations on the inner peripheral surface 27 at equal intervals. And, this release groove 31, It is also possible to provide the installation groove 32 which will be described later on the seat holder 14 of the inner circumferential surface 27 on the opposite side.

Although not shown, for a large-diameter valve having a size of 10B or more, a groove and a hole which can be fastened or removed by a fastening jig may be provided on the outer circumference of the ball seat 15, and in this case, assembly of the ball seat 15 It becomes easy.

On the other hand, the seat holder 14 is formed of a metal material such as carbon steel or a stainless steel material in a substantially cylindrical shape, and the mounting side of the ball seat 15 is formed by slightly expanding the diameter, and the ball is provided in the inside. The seat 15 is provided with an annular mounting groove 32. A female screw portion 33 that can be screwed to the male screw portion 30 is provided on the opening side of the inner circumference of the installation groove 32 as a projecting engagement portion. The female screw portion 33 is formed to be substantially half the length from the opening side to the installation groove 32, and the screw peak 33a is the valve body 10 of the size 3B, and is screwed to the male screw portion 30 of the ball seat 15. Peak 30a has the same specifications. In the rear side of the female screw portion 33, a bottomed hole 34 having a larger diameter than the outer diameter of the male screw portion 30 is provided, and the depth of the bottomed hole 34 is formed larger than the length of the male screw portion 30, and has a bottom. The inner diameter of the hole 34 is formed to be slightly larger than the outer diameter of the male thread portion 30.

The male screw portion 30 is screwed into the female screw portion 33, and the male screw portion 30 is housed in the bottomed hole 34, and the ball seat 15 is loaded into the mounting groove 32. After the male screw portion 30 and the female screw portion 33 are screwed together, the rear end side of the male screw portion 30 and the rear end side of the female screw portion 33 can be locked in the loading direction of the male screw portion 30. Therefore, the ball seat 15 can be prevented from being thrown out from the installation groove 32, and the ball seat 15 is in a free state, that is, the installation groove 32 is movable in at least the direction toward the center axis O of the flow path. It is installed under the state.

After the installation of the ball seat 15, in Fig. 5, when the excess pressure generated by the abnormal pressure rise in the groove 35 of the valve body 10 at the time of full closing or full opening occurs, the flow path is exceeded. When the fluid pressure in the portion 23 is high in the groove 35, the seat holder 14 is moved in the opposite direction to the ball 12 by the self-tightening force using the high pressure, and is formed by the back surface of the ball seat 15 in the installation groove 32. The aforementioned excess pressure flowing in the 15a side causes the ball seat 15 to be pushed toward the ball 12 side, and at this time, the excess pressure generated by the abnormal pressure increase in the groove 35 is released through the communication portion 40 toward the flow path 23. . Here, the abnormal pressure increase in the groove 35 means that the temperature of the fluid rises, or becomes high temperature by the environment provided by the valve body 10, or is surrounded by the valve body 11 and the ball 12 in the valve body 10 in the valve closed state, The phenomenon in which the pressure in the sealed space (groove 35) surrounded by the ball seat 15, the seat holder 14, and the like rises. Further, the ball seat 15 is pushed out toward the side of the ball 12, and is not limited to the state in which the position of the ball seat 15 is moved toward the side of the ball 12, but at least the state in which the ball seat 15 does not follow the seat holder 14 and is pressed toward the ball 12. .

Here, as shown in Fig. 7, when the pressure is applied to the side of the back surface 15a of the ball seat 15, the pushing load of the ball seat 15 is applied to the spiral peaks 30a and 33a, so it is necessary to set it so as to ensure the application. The ball 15 and the holder 14 are provided in such a manner that the pressure of the back surface 15a prevents the peak height of the material strength (the shear strength of the peak) of the ball seat 15 from being removed. In this case, the force applied to the spiral peaks 30a, 33a is prevented from exceeding the drop point of the material of the ball seat 15, and the size at which the peaks are stuck to each other even when the ball seat 15 is contracted at a low temperature in consideration of the lowest use temperature of the valve body 10 is considered. of The way to set.

The peaks 30a and 33a are preferably fine threaded threads. In this case, the length of the bolt can be shortened as much as possible, so that the number of peaks can be ensured and the height of the peak can be adjusted. Further, since the pitch of the fine thread is short, the portion which becomes an incomplete thread in the circumferential direction is less, and it is also preferable in the trunnion type ball valve of the present invention.

In the present embodiment, the valve body 10 of the size 3B is formed as a ball seat material: PTFE, a screw height: about 0.8 mm, a screw pitch: 1.5 mm (using a fine thread), and a minimum use temperature: -46 ° C, The amount of shrinkage in the radial direction of the ball seat is about 0.5 mm, and the abutting length is about 0.6 mm (heat shrinkage on the metal side is also considered).

When the ball seat 15 is attached to the seat holder 14, the male screw portion 30 is positioned in the mounting groove 32 in Fig. 4(a), and the ball seat 15 is rotated in the screwing direction to be screwed in the direction of the arrow. As shown in FIG. 4(b), when the ball stud 15 is screwed in when the screw peak 30a is detached from the screw peak 33a, the bolts are detached, and the ball seat 15 is detached from the seat holder 14 while being stopped. The state of freedom.

At this time, by making the depth of the bottomed hole 34 larger than the length of the male screw portion 30 as described above, the screw peak 30a surely exceeds the field of the screw peak 33a, so that the male screw portion 30 can be loaded into the housing. In the bottomed hole 34, between these spiral peaks 30a and 33a, as shown in Fig. 5, a clearance CL in the loading direction (the direction of the flow path central axis O in Fig. 1) is provided. The inner diameter of the bottomed hole 34 is slightly larger than the outer diameter of the male screw portion 30, and a gap G in the radial direction is also provided between these, thereby making the gap G The ball seat 15 can advance and retreat in a state where the sliding resistance is small in the range of the play CL of the seat holder 14. The size setting of the size of the clearance CL and the gap G is set in consideration of the environmental temperature at the time of assembly and the difference in the degree of cold and warmth caused by the difference in the assembly place. The case of this embodiment can correspond to an assembly temperature of up to 40 ° C in summer and 10 ° C in winter.

After the assembly, the ball seat 15 was rotated in the opposite direction to the screwing direction, and it was confirmed that the ball seat 15 was screwed again and did not fall off. In this case, the screw peaks 33a of the seat holder 14 and the highest portion (the full thread portion) of the screw peaks 30a of the ball seat 15 are in a locked state, and the ball seat 15 is rotated so that the start portions of the threads are mutually incomplete (incomplete The positions of the rear end sides of the threaded portions are different from each other. Thereby, the re-threading of the seat holder 14 of the ball seat 15 after installation is prevented, and the ball seat 15 is surely movable.

Here, in the case where the start portion of the thread tip is, for example, a clock, it is preferable to arrange the screw peak 30a at a position x of 3 o'clock in the second drawing. This is because when the valve body 10 in the valve closed state rotates the rod 13 counterclockwise to the valve open state, the flow path 23 closed by the ball 12 expands from the position x at 3 o'clock, and the valve is enlarged. When the flow rate at the beginning is fast, the ball seat 15 is easily ejected. Specifically, it is preferable that the peaks 33a of the seat holder 14 and the highest portions of the peaks 30a of the ball seat 15 are disposed at the position of the above-mentioned three o'clock.

In the above-described embodiment, the male screw portion 30 is provided on the outer peripheral side of the ball seat 15, and the female screw portion 33 is provided on the seat holder 14. However, the female screw portion is provided on the inner peripheral side of the ball seat 15, and the female retaining member 14 is provided in the seat holder 14. Thread In the same manner as described above, the ball seat 15 may be attached to the installation groove 32 of the seat holder 14 while being screwed in the same manner as described above.

The locking portion 30 and the engaging portion 33 may each be a thread. The locking portion 30 and the engaging portion 33 are mutually locked to prevent the ball seat 15 from being thrown out from the seat holder 14 and the ball can be removed. When the seat 15 is installed in the installation groove 32 in a free state, these can be set in various shapes.

Next, the action of the above-described embodiment of the trunnion type ball valve of the present invention will be described.

In the trunnion type ball valve of the present invention, in the fifth drawing, since the ball seat 15 can be prevented from being ejected into the installation groove 32 of the seat holder 14, the high pressure fluid can be supplied by the ball seat 15 installed in a free state. Since it is sealed, the number of parts can be minimized and the structure can be simplified, and only the ball seat 15 can be screwed into the seat holder 14 to be mounted.

In this assembly, since the male screw portion 30 and the female screw portion 33 can be screwed to fit the ball seat 15 to the bottomed hole 34, it is not necessary to apply excessive force, and wear and scratch can be prevented and less The assembly man-hour is correctly and easily installed to a predetermined position. In this case, a special jig or the like is not required, and a sufficient clearance CL and a gap G can be provided between the seat holder 14 and the ball seat 15 to prevent excessive stress from being generated from the initial state of assembly, and the operation is performed. Durability is also good. Further, it can be assembled in a state where it is not easily affected by the environmental temperature.

Moreover, by the screwing of the ball seat 15 to avoid the installation by press-in, the selection of the seat material is increased, for example, a material for low temperature can be used. And materials for high temperature, or materials of low-strength materials and high-strength materials, are also easily installed in the case where the ball seat 15 is formed of a high-strength material. After the ball seat 15 is completely screwed in, the ball seat 15 can be installed in a state of being idly rotated toward the bottomed hole 34 side, so that it is not necessary to separately provide a member for preventing the looseness, and the ball seat 15 can be prevented. Naturally loose and fall off.

When the valve body 10 is in the fully closed state, as shown in FIG. 3, the ball seat 15 is pushed toward the ball 12 by the coil spring 41 through the seat holder 14, whereby the sealing surface 25 of the ball seat 15 is borrowed. The seal is sealed from the ball 12 across the entire circumference to prevent leakage. In this case, the seat holder 14 and the cap 21 are sealed by the O-ring 42 and the gasket 43.

As shown in Fig. 7(a), the back surface 15a of the ball seat 15 is in close contact with the seat holder 14 by the sealing point P at the innermost diameter position, and prevents the fluid in the flow path 23 from passing through the groove 35 from this portion.

When the valve body 10 is actuated to be in a slightly open state, the ball seat 15 that is pressed against the ball 12 is not pressed by the rotation of the ball 12, and flows through the communication portion 40. The fluid pressure is a chamfered portion (not shown) applied to the vicinity of the sealing point P in the back surface 15a of the ball seat 15, and the ball seat 15 is instantaneously pushed out toward the ball 12 side as shown in Fig. 7(b).

At this time, the pinion peak 30a of the male screw portion 30 and the rear end side of the screw peak 33a of the female screw portion 33 abut against each other (lock), thereby preventing the ball socket 15 from being thrown out. When the pressure applied to the back surface 15a of the ball seat 15 and the pressure in the groove 35 become the same pressure, the force which pushes the ball seat 15 toward the ball 12 side disappears.

When the valve body 10 is in the fully open state, as shown in Fig. 1, the sealing surface 25 of the ball seat 15 is sealed and sealed to the ball 12 again across the entire circumference.

When the pressure in the groove 35 is increased by the abnormal pressure increase, the ball seat 15 is pressed by the pressure as shown in Fig. 5 and is tilted toward the inner diameter side as indicated by the arrow in the figure. By this deformation, the ball seat 15 and the ball 12 are sealed at a sealing point R which is slightly smaller than the sealing point before the abnormal pressure rise occurs, and the ball seat 15 and the seat holder 14 are at the sealing point by the sealing diameter ΦdR. P is sealed by the back seal diameter ΦdP.

In this ball seat 15, the pressure (groove pressure) in the groove 35 is applied to both the sealing surface 25 side and the back surface 15a side. Here, in the sealing surface 25 side and the back surface 15a side, each sealing point has a relationship of a sealing diameter ΦdR>back sealing diameter ΦdP, and a difference S is set in the sealing diameter. By the difference S of the diameters, the force applied to the back side of the ball seat 15 by the groove pressure is made larger than the force applied to the side of the ball 12, and the ball seat 15 is pushed out toward the ball 12 side.

This pushing force can be expressed as follows: [groove pressure PR] × [pressure receiving area M of the groove pressure in the back surface of the ball seat 6]

And the pressure receiving area M can be expressed as follows: the pressure receiving area M = (ΦdR - ΦdP) ² × π × 4

On the other hand, in the seat holder 14, the groove pressure is applied Both the cap 21 side and the ball seat 15 are provided on the side of the groove 32. The holder 14 is sealed in the cap 21 side by the O-ring 42 and the inner circumference of the cap 21. In the present embodiment, the sealing point is set to D, and the sealing diameter is set to the holder sealing diameter ΦD.

Here, in the side of the cap 21 and the installation groove 32 of the ball seat 15, the difference T is set in the seal diameter so that each sealing point has a relationship of ΦdD > ΦdR. With the difference T of the diameter, the seat holder 14 is pulled back toward the side opposite to the ball 12 by the groove pressing force against the elastic force of the coil spring 41.

This pull-back force, which is also referred to as self-tightening force, can be expressed by [groove pressure PR] × [pressure-receiving area N of the groove in the installation groove 32 of the ball seat 15]. Further, the pressure receiving area N can be expressed by the pressure receiving area N = (ΦdP - ΦdR) ² × π × 4.

The ball seat 15 is pushed out toward the side of the ball 12 by the groove pressure, as shown in Fig. 6. Thus, the excess pressure from the groove 35 flowing into the gap G of the male screw portion 30 of the ball seat 15 in the installation groove 32 and the female screw portion 33 of the seat holder 14 is to push the ball seat 15 toward the ball 12 side. The excess pressure in the groove 35 is released from the inner peripheral surface 27 of the ball seat 15 and the communication portion 40 between the installation grooves 32 through the release groove 31 toward the flow path on the primary side of the ball 12.

And because the seat holder 14 is also pulled back toward the opposite side of the ball 12 as the aforementioned groove pressure, it can be quickly and easily attached to the back side 15a of the ball seat 15 and the seat holder 14 with the pushed ball seat 15 When a gap G is formed between the installation grooves 32, excess pressure in the groove 35 can be released from the back surface 15a of the ball seat 15 through the communication portion 40 toward the flow path 23 on the primary side.

In this way, the ball seat 15 can be held in a free state toward the seat. When the installation groove 32 of the member 14 moves and any of the factors cause abnormal pressure rise in the groove 35, a mechanism for escaping the pressure toward the flow path side is provided, so that the self-release function is exerted to seal the back side. The position of the point P is constantly stabilized by the self-release function, and the abnormal pressure rise can be surely eliminated, and further, the directivity of self-release can be easily controlled.

When the ball seat 15 is expanded by the high-pressure fluid to increase the volume, the volume increase is also moderated in the clearance CL, and the escape of the ball seat 15 and the wear of the sealing surface 25 caused by the bulging toward the ball 12 side can be avoided. .

In this case, the scooping of the ball seat 15 by the negative pressure of the fluid pressure is controlled by the relationship between the shear strength of the screw peak and the negative pressure of the ball seat, that is, the strength of the material and the pressure on the back side are adjusted. When the spherical seat 15 is formed by the relationship of the area, the sputum can be surely prevented.

In Fig. 8, a second embodiment of the trunnion type ball valve of the present invention is shown. Further, the same portions as those of the above-described embodiment after the embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

Here, as shown in Fig. 8, when the ball seat 15 is pressed against the ball 12, it is pressed against the spherical surface of the ball seat 15, particularly the sealing surface side, as shown by the arrow. A force that deforms in the direction of the diameter expansion is applied. In this case, the sealing positions of the ball seat 15 and the ball 12 may deviate.

When the ball seat 15 is expanded in diameter and the female screw portion 33 provided in the mounting groove 32 of the seat holder 14 is excessively pressed, the ball seat 15 may be damaged. The diameter expansion phenomenon of the ball seat 15 is a fluid that flows quickly in a narrow space of the ball 12 and the ball seat 15 in the slightly opened state of the valve body 10 shown in Fig. 7. It becomes more noticeable when infiltrated.

In order to prevent this, in this embodiment, the leading end side of the spiral peak 33a of the female screw portion 33 is cut away to form a surface 33b parallel to the outer circumference of the ball seat 15. Thereby, the stress concentration in the contact portion between the screw peak 33a and the ball seat 15 can be alleviated, and the damage of the ball seat 15 can be prevented.

Further, by setting the inner diameter of the parallel surface 33b to be close to the outer diameter of the ball seat 15, the diameter expansion of the ball seat 15 can be suppressed, and the deviation of the sealing position of the ball seat 15 and the ball 12 can be reduced.

In Fig. 9, a third embodiment of the trunnion type ball valve of the present invention is shown. In this embodiment, on the side of the back surface 15a of the ball seat 15, the back surface 15a of the ball seat 15 is made by the sealing point P close to the innermost diameter of the inclined surface 15b by forming the inclined inclined surface 15b toward the inner diameter. The seal between the mounting grooves 32 of the seat holder 14 is provided. Thereby, in the fully open state shown in FIG. 1 or the fully closed state shown in FIG. 3, the fluid pressure from the flow path 23 does not penetrate in the back surface 15a of the ball seat 15.

In the eighth embodiment, the back surface 15a of the ball seat 15 is formed in parallel with the bottom surface of the installation groove 32 of the seat holder 14 in a plane perpendicular to the center axis O of the flow path of the first figure, and is close to The annular projection 45 may be provided at the sealing point P at the innermost diameter position. In this case, the annular projections 45 on the most inner diameter side of the back surface 15a of the ball seat 15 can seal between the installation grooves 32 of the seat holder 14.

In Fig. 10, a seat holder and a ball seat in a fourth embodiment of the trunnion type ball valve of the present invention are shown. In this embodiment, as shown in Fig. 10(a), the seat holder 14 can be substituted for the inner circumference of the installation groove. The female screw portion is provided with an annular edge portion 51 having a notch portion 50 of 2 to 4 in the circumferential direction. Instead, the male screw portion provided on the outer circumference of the ball seat 15 may be provided in the circumferential direction corresponding to the notch portion. An annular projection 52 at 2 to 4 of 50.

When the ball seat 15 is attached to the seat holder 14, the ball seat 15 holder 14 is loaded in a state where the annular projection 52 is fitted to the cut portion 50 as shown in Fig. 10(b), and then The annular projection 52 shown in Fig. 10(c) is the direction of the arrow of the ball holder 15 with respect to the seat holder 14 toward the figure 10(b) until the position of the opposite side with respect to the annular edge portion 51. Rotate. Thereby, in FIG. 10(c), the annular projection 52 is engaged with the annular edge portion 51, whereby the spherical seat 15 can be moved in a free state, that is, movable to the installation groove 32 by the rotation engagement. Installed under the condition and prevented from falling off.

In Fig. 11, a fifth embodiment of the trunnion type ball valve of the present invention is shown.

In this embodiment, the A portion is formed to be annularly formed on the side of the installation groove 32 of the ball seat 15, and the A portion is abutting against the installation groove 32 and can be back-sealed so as to be a fulcrum position. be set to. The ball seat 15 is prevented from being ejected from the installation groove 32, and is elastically deformable in a direction in which the fulcrum position A is enlarged toward the ball 12 side, and is in the flow path to the valve body 10 of Fig. 12 . The direction in which the axis (the center axis of the flow path) O is movable is free.

In this case, the inner diameter L1 of the portion A is set to be closer to the inner diameter than the sealing portion of the ball seat 15, that is, the sealing surface 25, so that the portion A is A gap H is formed between the ball seat 15 and the bottomed hole 34 of the installation groove 32 by being formed in a ring shape. The ball seat 15 is elastically deformed so as to enlarge the portion A as a fulcrum at a high pressure, and seals the sealing surface 25 from the outer diameter toward the inner diameter side at least in surface contact with the ball 12. At this time, by providing the gap H, the gap H also contributes to the rotational action at the time of elastic deformation in such a manner that the ball seat 15 is enlarged.

The sealing surface 25 is formed by a spherical surface that is in contact with the outer peripheral surface of the ball 12, that is, a spherical surface portion. The sealing portion C is formed on the primary side in the flow path 23 direction of the sealing surface 25, and the sealing portion B is formed on the secondary side. The seal portion B is in line contact with the ball 12 at a low pressure.

The fulcrum position is the positional relationship between the A portion and the sealing surface 25, that is, the sealing portion B and the sealing portion C. When the inner diameter of the sealing portion B is set to L2 and the inner diameter of the sealing portion C is set to L3, The inner diameter dimension L1 < the inner diameter dimension L3 < the inner diameter dimension L2 is set so that the inner diameter dimension of the A portion, the seal portion B, and the seal portion C is A < C < B.

Further, when the ball seat 15 is installed in the initial stage of assembly of the installation groove 32 and the fluid pressure is low pressure, the inner diameter ΦDS from the sealing portion C of the sealing surface 25 to the sealing portion B is the ball diameter ΦDB of the ball 12. Different, these are the different diameters. In the present embodiment, the inner diameter ΦDS is a shape having a smaller diameter than the ball diameter ΦDB, that is, a relationship in which the inner diameter ΦDS of the seal portion <the ball diameter ΦDB is formed. The center Q1 of the inner diameter ΦDS and the center Q2 of the spherical diameter ΦDB are as shown in Fig. 12, and any one of them is disposed on the flow path central axis O of the valve body 10.

With these, the initial stage of assembly and fluid pressure are low pressure. In other words, the contact of the ball 12 toward the sealing portion B is maintained in the in-line contact state, and the sealing portion C is in a non-contact state with the spherical surface 16.

A predetermined clearance CL is provided between the inner circumferential surface 32a of the installation groove 32 and the outer circumferential surface 15c of the sealing surface side of the ball seat 15, and the spherical seat 15 can be enlarged toward the clearance CL side at a high pressure. And can suppress excessive expansion.

In the outer peripheral surface 15c, on the rear side of the installation groove 32, the projecting engagement portion 60 is formed to have a length which is approximately half the thickness of the installation direction of the ball seat 15. On the other hand, in the installation groove 32 of the seat holder 14, the projecting locking portion 61 is formed from the opening side to approximately half the length of the installation groove 32. The above-described play CL is provided between at least the inner peripheral surface 32a of the locking portion 61 and the outer peripheral surface 15c side of the engaging portion 60 of the ball seat 15 on the ball 12 side.

In the rear side of the locking portion 61 of the seat holder 14, a bottomed hole 34 having a larger diameter than the outer diameter of the engaging portion 60 is provided, and the depth of the bottomed hole 34 is larger than the length of the engaging portion 60. The inner diameter of the bottomed hole 60 is formed to be slightly larger than the outer diameter of the engaging portion 60.

In the seat holder 14, the ball seat 15 is attached to the installation groove 32 in a state in which the engagement portion 60 is housed in the bottomed hole 34. After the ball seat 15 is installed, the ball seat 15 is prevented by the rear end side of the engaging portion 60 and the rear end side of the locking portion 61 being slidably facing each other in the loading direction of the engaging portion 60. The ball 32 is detached from the installation groove 32, and the ball seat 15 is in a free state.

After the seat holder 15 of the ball seat 15 is mounted, the ball bearing 15 is provided between the inner peripheral surface 27 side and the outer peripheral side (the engaging portion 60 side). The communication portion 40 that communicates the groove 35 and the upstream side of the ball 12 is provided. Thus, if the excess pressure generated by the abnormal pressure rise in the groove 35 of the valve body 10 at the time of full closing or full opening occurs, that is, the fluid pressure in the flow path 23 exceeds the pressure in the groove 35. At this time, the seat holder 14 is moved in the opposite direction to the ball 12 by the self-tightening force of the high pressure, and the excess pressure is caused by the aforementioned excessive pressure flowing into the side of the back surface 15a of the ball seat 15 in the installation groove 32. The seat 15 is pushed out toward the side of the ball 12, and at this time, the excess pressure generated by the abnormal pressure increase in the groove 35 is released into the flow path 23 through the communication portion 40.

The trunnion type ball valve in this embodiment is optimal in the case of a large diameter of 8 inches or more. In the present embodiment, for example, in the case of the valve body 10 of the size 12B of the class 600, the ball seat material: PTFE, Ball diameter: Φ460mm, inner diameter ΦDS of the seal portion is reduced by 3% to 5% for the ball diameter ΦDB, the inner diameter (inner diameter size L3) of the seal portion C, and the fulcrum position is the inner diameter of the A portion (inside) The difference in size of the diameter L1) is 2 mm or less (1 mm or less in the radial direction), and the difference in size between the inner diameter (inner diameter L2) of the sealing portion B and the inner diameter (inner diameter L3) of the sealing portion C: 2 mm or more ( If it is 1 mm or more in the radial direction, it is sufficient. In this case, the expanded elastic deformation of the ball seat 15 toward the ball 12 side at the time of the high-pressure load is assumed to be expanded by 1 degree.

Further, the sealing surface 25 of the ball seat 15 is provided in the vicinity of the seal portion facing the ball 12, and may have a shape other than the spherical portion when the height of the fluid pressure is in line contact with the ball 12 or even in surface contact, and may be formed, for example, in a tapered shape. And the arc surface can also be used.

When the ball seat 15 is mounted on the seat holder 14, The ball seat 15 is inserted from the opening side in the direction of the installation groove 32 so that the locking portion 61 pushes the engagement portion 60. When the engaging portion 60 reaches the bottomed hole 34, the mounting of the ball seat 15 is completed, and the ball seat 15 is detached from the seat holder 14 and is attached in a free state. At this time, as described above, by making the depth of the bottomed hole 34 larger than the length of the engaging portion 60, the engaging portion 60 can surely exceed the area of the locking portion 61, and the engaging portion 60 can be received in the bottom. Hole 34.

After the loading of the ball seat 15, a clearance CL is formed between the mounting groove 32 and the opening CL in the direction in which the clearance CL is centered on the ball 12 side of the ball seat 15 as a fulcrum position. It can be elastically deformed.

A space U is provided in the loading direction (the direction of the axis O of the flow path in the first drawing) between the engaging portion 60 and the locking portion 61 as shown in Fig. 11 . The inner diameter of the bottomed hole 34 is set to be slightly larger than the outer diameter of the engaging portion 60, and a gap G in the radial direction is also formed between these. By the gap G, the ball seat 15 is in the range of the space U of the seat holder 14, and it is possible to advance and retreat in a state where the sliding resistance is small.

The size setting of the clearance CL, the space U, and the size of the gap G is set in consideration of the environmental temperature at the time of assembly and the difference in the degree of cold and warmth caused by the difference in the assembly place. The case of this embodiment can correspond to an assembly temperature of up to 40 ° C in summer and 10 ° C in winter.

When the fluid pressure on the upstream side of the flow path 23 is a low pressure in the valve body 10, as shown in Fig. 11, the seal is made in a state in which the A portion of the ball seat 15 abuts against the bottom surface side of the installation groove 32. Portion B is in line contact with ball 12 to maintain a sealed state. The sealing ratio of the contact of this line contact with the surface In the case of a lower pressure, the sealing force is lowered. Since the fluid is at a low pressure, the wear of the sealing performance is not caused by the failure point of the ball seat material, and the leakage at the low pressure can be reliably prevented.

When the high-pressure fluid pressure is applied, in addition to the elastic force of the coil spring 41 in the seat holder 14, since the force of the fluid pressure by the high pressure is applied, the ball seat 15 is further pushed toward the side of the ball 12, The ball seat 15 is elastically deformed in the direction in which the ball 12 side is enlarged by the height of the corresponding fluid pressure as shown in Fig. 13, and the sealing surface 25 is at least in contact with the ball 12 from the outer diameter side toward the inner diameter side. The state is sealed so that the high pressure fluid can be reliably sealed.

In this case, in the eleventh diagram, the position of the fulcrum, that is, the position A and the sealing portion, that is, the positional relationship between the sealing portion B and the sealing portion C, is A<C<B for the inner diameter dimension, and the sealing portion B is located In the outer diameter side of the A portion, the sealing portion B side is rotated to the left in a direction away from the ball 12 in the rotation action of the Fig. 13, and the sealing portion that separates the ball 12 from the rotation is thereby rotated. The C side is in contact with the ball 12 on the ground.

By providing a predetermined clearance CL between the installation groove 32 and the ball seat 15, the operation when the sealing surface 25 side is deformed in the expansion direction is prevented from being hindered, and the outer circumferential surface 15c of the ball seat 15 is mounted. When the inner peripheral surface 32a of the groove 32 is in contact, the over-expansion of the ball seat 15 can be suppressed to ensure the sealed state of the ball 12.

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit and scope of the invention.

10‧‧‧ valve body

11‧‧‧ valve body

12 ‧ ‧ ball

12a‧‧‧through hole

13‧‧‧ great

13a‧‧‧上棒

13b‧‧‧下棒

14‧‧‧ holders

15‧‧‧ tee

15a‧‧‧Back

20‧‧‧Circular valve body

21‧‧‧ Cap

22‧‧‧Bolt nuts

23‧‧‧Flow

25‧‧‧ sealing surface (sealing part)

27‧‧‧ inner circumference

30a‧‧‧Spiral peak

32‧‧‧Installation ditch

35‧‧‧ Groove

41‧‧‧ coil spring

42‧‧‧O-ring

43‧‧‧ Seal

Claims (11)

A trunnion type ball valve is provided with one or both of a ball having a through hole provided in a valve body, and the ball passing rod is rotatably provided to prevent the ball seat The ball seat is formed in the installation groove formed in the seat holder, and the ball seat is installed in a free state, and is characterized in that the abnormal pressure in the groove is fully closed or fully opened. The excess pressure generated is caused by the self-tightening force by the pressure to move the seat holder in the opposite direction to the ball, and the ball seat is moved toward the ball side by the aforementioned excess pressure flowing into the back side of the ball seat in the installation groove. It is pushed out and released into the flow path through the communication portion provided between the inner circumferential surface of the ball seat and the installation groove. The trunnion type ball valve according to the first aspect of the invention, wherein the engaging portion provided on the opening side of the inner circumference of the installation groove is fitted to the locking portion provided on the outer circumferential mounting side of the ball seat. The direction is slidably facing to prevent the ball seat from being detached from the mounting groove of the seat holder, and the ball seat is mounted in the installation groove in a free state. The trunnion type ball valve according to the second aspect of the invention, wherein the female screw portion provided on the inner circumference of the installation groove is an engagement portion, and the male screw portion of the ball seat is screwed to the female portion. The screw portion has a rear end side of the male screw portion and a rear end side of the female screw portion so as to be lockable to prevent the ball seat from being thrown out. The trunnion type ball valve according to the third aspect of the invention, wherein the screw peak of the inner end of the female screw portion and the peak of the outer end of the male screw portion are locked to prevent the ball seat from being thrown out. The trunnion type ball valve according to any one of claims 1 to 3, wherein the inner circumferential surface of the spherical seat or the mounting groove of the seat holder facing the inner circumferential surface is formed At least one release groove constituting the aforementioned communication portion. The trunnion type ball valve according to the first aspect of the invention, wherein the fulcrum position at which the back surface of the ball seat is sealed, that is, the inner diameter of the portion A is set to be larger than the inner diameter of the sealing portion of the ball seat, so that the high pressure is The ball seat is elastically deformed so that the A portion is enlarged as a fulcrum, and the sealing portion is sealed at least in surface contact state from the outer diameter side toward the inner diameter side. The trunnion type ball valve according to the sixth aspect of the invention, wherein the position of the fulcrum, that is, the portion A and the sealing portion, that is, the positional relationship between the sealing portion B and the sealing portion C, is A<C<B for the inner diameter dimension. . In the trunnion type ball valve according to the seventh aspect of the invention, in the case where the initial stage of assembly and the fluid pressure are low pressure, the sealing portion B is in a state of maintaining a line contact, and the sealing portion C is in a non-contact state with the spherical surface. The trunnion type ball valve according to any one of claims 6 to 8, wherein the sealing portion of the ball seat is formed into a spherical surface, and the spherical surface is disposed in the same manner as the center of the ball It is formed on the flow axis core in the valve body and has an inner diameter smaller than the spherical shape of the ball. Such as the trunnion type ball valve of claim 6 of the patent scope, wherein A predetermined play is provided between the inner circumferential surface of the installation groove and the outer circumferential surface of the sealing surface side of the ball seat, and the spherical seat is enlarged at a high pressure, and excessive expansion is suppressed. The trunnion type ball valve according to claim 10, wherein a play is provided between the inner circumferential surface of the locking portion formed in the installation groove and the outer circumferential surface side of the spherical seat.