JPH0542845U - Top entry type 3-way switching ball valve - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a top entry type three-way switching ball valve that can improve operability when opening and closing the valve and can extend the life of the seat packing. [Structure] In the lower part 1 of the valve body, first and second axial flow holes 3 and 4 extending in opposite directions with a valve seat 2 sandwiched therebetween and extending in a direction perpendicular to the axial flow holes 3 and 4 are provided. The existing vertical flow holes 12 are formed respectively. On the outer surface of the ball 5, the peripheral regions 22 and 23 surrounding each open end of the through hole 6 and the peripheral region 24 surrounding the open end of the vertical hole 16 are formed into a curved surface having a radius r with the center of the ball as the center of curvature. A region 25 on the opposite side of the peripheral region 24 is formed into a curved surface having a radius R with the center of curvature as the center of curvature. The curved surface 25 having the radius R and the curved surfaces 22, 23 and 24 having the radius r are set to R> r so that the former compresses the sheet packings 7, 8, 13 and 15 sufficiently and the latter does not substantially compress. Has been.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a top entry type three-way switching ball valve that opens and closes a valve by rotating a ball in a valve body by rotating a valve rod.

[0002]

[Prior Art]

 Three-way switching ball valves are attached to pipes, tanks, etc. and are widely used to control the fluid flowing through them. This ball valve consists of a side entry type ball valve in which the side of the valve body is divided and the ball is mounted from this divided part, and a valve body is divided into an upper part and a lower part and the ball is mounted from the upper part to the lower valve seat. It can be roughly classified into a top-entry type ball valve.

The side entry type ball valve has an advantage that the seat packing for sealing the ball can be surely loaded in the valve body. However, there is a drawback in that it is extremely difficult to replace a worn or damaged seat packing. In detail, after installing a side-entry type ball valve in a piping system, when replacing a worn or damaged seat packing, the ball valve must be disassembled. However, it is very difficult to disassemble the side entry type ball valve after mounting it on the piping system because of its structure.

On the other hand, the top entry type ball valve has the advantage that the seat packing can be replaced more easily than the side entry type ball valve. However, the top-entry ball valve has a structure in which the ball is always urged downward by a spring to firmly adhere to the seat packing so that the seat packing is easily plastically deformed. There was a problem of poor durability.

Therefore, a top entry type ball valve which solves such a drawback is disclosed in US Pat. No. 4,147,326. In this top-entry ball valve, as shown in FIG. 7, a valve seat 2 and first and second axial flow passages extending in opposite directions sandwiching the valve seat 2 are provided in a lower portion 1 of the valve body. Holes 3 and 4 are formed respectively. A ball 5 is rotatably accommodated in the valve seat 2, and a through hole 6 is formed in the ball 5 so that the first axial direction flow hole 3 and the second axial direction flow hole 4 can communicate with each other. Seat packings 7 and 8 are interposed between the ball 5 and the first and second axial flow holes 3 and 4, respectively. On the outer surface of the ball 5, only the periphery 5a of the opening end of the through hole 6 is chamfered in a tapered shape, and the remainder is formed into a perfect circular shape. Therefore, when the ball valve is opened, the tapered portions 5a face the seat packings 7 and 8, respectively, and the seat packings 7 and 8 are hardly compressed. However, when the ball 5 is rotated 90 ° and the valve is closed, the perfect circle portion of the ball 5 faces the seat packings 7 and 8 and compresses and seals them.

In the top entry type ball valve having this configuration, the seat packings 7 and 8 are compressed only when the valve is closed and not compressed when the valve is opened, so plastic deformation, wear and damage are less likely to occur. However, in this top-entry type ball valve, when the ball 5 is rotated 90 ° from the open state to the closed state, the seat packings 7 and 8 move closely from the tapered portion 5a to the perfect circle portion, so that the seat packing 7, No. 8 is subject to a sudden load and is apt to be worn or damaged, resulting in a new problem that shortens the life of the seat packing. Further, the above-described rotation of 90 ° has a problem that the operability is poor because the rotation torque rapidly increases at that time.

The present applicant has applied for a top entry type ball valve that solves these problems as Japanese Patent Application No. 2-82530. In the top entry type ball valve disclosed in this prior application, as shown in FIGS. 8 and 9, a region 9 surrounding the opening end of the through hole 6 of the ball 5 is a curved surface having a radius r, and 90 ° from this region 9. A curved surface having a radius R is formed on the displaced area 10. The curved surface 9 having the radius r and the curved surface 10 having the radius R are smoothly connected, and the curved surface 10 having the radius R sufficiently compresses the seat packing, but the curved surface 9 having the radius r does not substantially compress the seat packing. , Radius R is set to be larger than radius r. As described above, in the top entry type ball valve according to the prior application, since the curved surface 10 having the radius R and the curved surface 9 having the radius r are smoothly connected, the ball 5 rotates smoothly without a sudden torque change. .. Therefore, the operability of the ball rotation is improved and the seat packing is prevented from being worn or damaged.

[0008]

[Problems to be solved by the device]

 However, the top-entry ball valves relating to the above-mentioned US patent and the utility model registration application of the earlier application are all related to the two-way switching ball valve, not the three-way switching ball valve. This is probably because the three-way switching ball valve requires at least three seat packings, and it was difficult to reliably seal the ball and the seat packing in all of them. SUMMARY OF THE INVENTION An object of the present invention is to provide a top entry type three-way switching ball valve having a relatively simple structure, which improves the operability when opening and closing the valve and extends the life of the seat packing.

[0009]

[Means for Solving the Problems]

 To achieve this object, the present invention relates to a valve seat and first and second axial flow holes that extend in opposite directions with the valve seat sandwiched between the valve seat and the axial flow hole. A valve body having a vertical flow hole extending substantially vertically and a through hole that is rotatably housed in the valve seat and is capable of communicating the first and second axial flow holes with each other. From the ball on the side opposite to the connecting portion with the ball and the ball that is connected to the ball and drives the ball to rotate. A projecting shaft portion, a recess formed in the valve seat, which is fitted to the shaft portion to prevent the ball from moving due to fluid pressure, and the passage holes and the valve seat. Top including seat packings respectively interposed between the valve seat and the ball at a difference point In an inlet type three-way switching ball valve, the outer surface of the ball has a peripheral region surrounding each opening end of the through hole and the opening end of the vertical hole with a radius r of which the center of curvature is the center of the ball. The curved surface is a curved surface with a radius R, which is larger than the radius r with the center of curvature of the ball as the center of curvature, and the region on the opposite side of the opening end of the vertical hole faces the seat packing. When this is done, it is compressed by a predetermined amount, and the curved surface of the radius r is set so as not to substantially compress it when facing the sheet packing.

[0010]

[Action]

 When the through hole of the ball communicates with the first and second axial flow holes, the seat packings of the first and second axial flow holes are opposed to the curved surface of the ball having a radius r. Is virtually uncompressed. Since the curved surface of the ball having a radius R is opposed to the seat packing of the vertical flow hole, the seat packing is compressed and reliably seals between the vertical flow path and the ball.

When the vertical hole of the ball is located in the first axial flow hole and the through hole of the ball is located in the vertical flow hole, the seat packing of the first axial flow hole and the seat packing of the vertical flow hole are Since the curved surfaces having the radius r of the ball face each other, these sheet packings are not actually compressed. Since the curved surface having the radius R of the ball is opposed to the seat packing of the second axial direction communication hole, these seat packings are compressed and reliably seal the space between the second axial direction communication hole and the ball. When the vertical hole of the ball is located in the second axial flow hole and the through hole of the ball is located in the vertical flow hole, the radius of the ball between the seat packing of the second axial flow hole and the seat packing of the vertical flow hole. Since the r curved surfaces face each other, these sheet packings are not actually compressed. Since the curved surface of the ball having a radius R is opposed to the seat packing of the first axial direction communication hole, these seat packings are compressed and reliably seal the space between the second axial direction communication hole and the ball. As described above, since each sheet packing is not always compressed, plastic deformation hardly occurs. In addition, since the ball is formed with a smooth curved surface, it can be smoothly rotationally driven without a sudden change in torque.

[0012]

【Example】

 An embodiment of the top entry type three-way switching ball valve according to the present invention will be described below with reference to FIGS. 1 to 6 in which the same parts as those in FIGS. 1 and 2, the valve body is composed of a lower body 1 and an upper body, that is, a cap 11. In the lower part 1 of the valve body, a valve seat 2 and first and second axial flow holes 3 and 4 extending in opposite directions with the valve seat 2 interposed therebetween, and from the valve seat 2 to the first and second shafts Vertical flow holes 12 extending substantially perpendicular to the direction flow holes 3 and 4 are formed respectively. A ball 5 is rotatably accommodated in the valve seat 2, and seat packings 7, 8 and 13 are interposed between the ball 5 and the first and second axial flow holes 3 and 4 and the vertical flow hole 12, respectively. Has been done. Further, the seat packing 15 is also interposed between the ball 5 and the closing wall 14 on the opposite side of the vertical flow hole 12.

The ball 5 is provided with a through hole 6 capable of communicating the first axial direction through hole 3 and the second axial direction through hole 4, and a vertical hole 16 perpendicular to the through hole 6. Perforated. A valve rod 17 is attached to the ball 5, and a handle 18 is attached to the valve rod 17. Further, a gland packing 19, a gland sleeve 20, a gland presser 21 and the like are installed between the valve rod 17 and the cap 11.

As shown in FIGS. 2, 3, and 4, the outer surface shape of the ball 5 is such that regions 22 and 23 surrounding both open ends of the through hole 6 and a region 24 surrounding the open ends of the vertical holes 16 are shown. Are formed on a curved surface having a radius r having the center of curvature O1 as the center of curvature, and an area 25 opposite to the area 24 is formed on a curved surface having a radius R having the center of curvature of the ball center O1. The size relationship between the radius R and the radius r is such that when the curved surfaces 22, 23, 24 of the radius r face the sheet packings 7, 8, 13, 15, they are not substantially compressed and the curved surface of the radius R 2 It is determined that R> r so that when 25 is opposed to the sheet packings 7, 8, 13 and 15, it is sufficiently compressed.

Further, the ball 5 is a trunnion type, and a shaft portion 26 is projectingly provided at the bottom of the ball, and the shaft portion 26 is fitted in the recess 27 formed in the valve seat 2, so that the fluid pressure The movement of the ball 5 due to the action is prevented. The lower part 1 of the valve body, the cap 11 and the balls 5 may or may not be provided with a fluororesin lining.

Next, the operation of this embodiment will be described. In FIG. 2, the ball 5 has a through hole 6 facing the first axial flow hole 3 and the second axial flow hole 4, a vertical hole 16 facing the closing wall 14, and is open in the axial direction. The valve is closed and is closed in the direction perpendicular to the axis. At this time, since the curved surfaces 22, 23, 24 having a half diameter r face the sheet packings 7, 8, 15 respectively, these sheet packings 7, 8, 15 are hardly compressed. Since the curved surface 25 having the radius R faces the seat packing 13, the seat packing 13 is sufficiently compressed and has a sufficient sealing action. Therefore, the vertical flow hole 12 is surely closed.

FIG. 5 shows a state in which the ball 5 is rotated counterclockwise by 90 ° from the state of FIG. 2, in which the first axial flow hole 3 and the vertical flow hole 12 are communicated with each other, and the second shaft Directional flow hole 4 is closed. Since the curved surface 25 having the radius R is opposed to the sheet packing 8 of the second axial flow hole 4, the second axial flow hole 4 is reliably sealed. FIG. 6 shows a state in which the ball 5 is rotated by 90 ° in the clockwise direction from the state of FIG. 2, the second axial flow hole 4 and the vertical flow hole 12 are communicated with each other, and the first axial flow hole 3 Is closed. Since the curved surface 25 having the radius R faces the sheet packing 7 of the first axial direction through hole 3, the first axial direction through hole 3 is reliably sealed. In the above embodiment, four sheet packings 7, 8, 13, 15 were used. However, the seat packing 15 in the closing wall 14 can be omitted.

[0018]

[Effect of the device]

 As is apparent from the above description, according to the present invention, the outer surface of the ball has a radius of which the peripheral regions surrounding the open ends of the through holes and the open ends of the vertical holes respectively have the center of curvature at the center of the ball. r is a curved surface, and the area opposite to the opening end of the vertical hole is a curved surface with a radius R that is larger than the radius r with the center of curvature of the ball as the center of curvature, and the curved surface with radius R is when facing the sheet packing. It is compressed by a predetermined amount, and the curved surface with radius r is set so as not to substantially compress it when facing the seat packing, so that early plastic deformation of the seat packing can be prevented and the ball It can be rotated smoothly without a sudden torque change, and operability can be improved. Further, since the ball is a trunnion type in which the shaft is fitted in the recess formed in the valve seat, it is not moved by the fluid pressure. Therefore, a sufficient sealing effect can be obtained by forming only the area on the opposite side of the opening end of the vertical hole to the curved surface having the radius R.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a top entry type three-way switching ball valve according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a partial cross-sectional view showing the shape of the ball of the above embodiment.

FIG. 4 is a side view of the ball of FIG.

5 is a sectional view similar to FIG.

6 is a sectional view similar to FIG.

FIG. 7 is a sectional view showing a conventional top entry type two-way switching ball valve.

FIG. 8 is a partial cross-sectional view showing the shape of balls of a top entry type two-way switching ball valve according to the prior application.

9 is a side view of FIG.

[Explanation of symbols]

 2 Valve Seat 3 First Axial Flow Hole 4 Second Axial Flow Hole 5 Ball 6 Through Hole 7 Seat Packing 8 Seat Packing 12 Vertical Flow Hole 13 Seat Packing 15 Seat Packing 16 Vertical Hole 17 Valve Rod 22 Curved Radius r 23 Curved surface with radius r 24 Curved surface with radius r 25 Curved surface with radius R 26 Shaft portion 27 Recessed portion

Claims (1)

[Scope of utility model registration request] 1. A valve seat and first and second axial flow holes extending in opposite directions with the valve seat interposed therebetween, and extending from the valve seat in a direction substantially perpendicular to the axial flow hole. A valve body having a vertical flow hole, a through hole rotatably housed in the valve seat and capable of communicating the first and second axial flow holes, and a vertical direction extending from the through hole in a substantially vertical direction. Balls each having a hole, a valve rod connected to this ball to drive it, a shaft portion projecting from the ball on the opposite side of the connecting portion with the valve rod, and a valve seat. A recess formed to fit the shaft portion to prevent movement of the ball due to fluid pressure; and a space between the valve seat and the ball at each intersection of each of the flow holes and the valve seat. Top-entry three-way switching ball bal with intervening seat packing In the outer surface of the ball,
Peripheral regions surrounding the open ends of the through holes and the open ends of the vertical holes are curved surfaces with a radius r having the center of curvature as the center of curvature of the ball, respectively, and on the opposite side of the open ends of the vertical holes. The area has the radius r with the center of curvature of the ball as the center of curvature.
Is a curved surface having a radius R larger than that, and the curved surface having the radius R compresses the sheet packing by a predetermined amount when facing the sheet packing, and the curved surface having the radius r does not substantially compress it when facing the sheet packing. A top entry type three-way switching ball valve that is characterized as follows.