JPH0220542Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an improvement of a ball valve, and particularly to an improvement of a wiper in a sealing portion between a ball valve and a valve body.

PRIOR ART FIG. 1 is a side sectional view of a conventional ball valve, in which a spherical ball 2 with a transverse through hole 1 in the center is attached to an upper stem provided on the vertical axis of a centrally welded valve body 3. 4 and lower stem 5
The inflow hole 6 and the outflow hole 7 on the valve body 3 side communicate with each other through the through hole 1 when the valve is fully opened as shown in FIG. .

The upper stem 4 and the ball 2 are integrally connected by a key 8.
When rotated 90 degrees, the inlet and outlet holes 6 and 7 of the valve body and the through hole 1 on the ball 2 side are perpendicular to each other,
The communication between the inflow and outflow holes 6 and 7 is cut off. This state is the fully closed state of the ball valve.

From the inflow hole 6 to the outflow hole 7 in such a fully closed state
In order to eliminate fluid leakage, a seal ring 10 for preventing leakage is attached to the sliding contact portion 9 between the valve body 3 and the ball 2.

FIG. 2 is a side sectional view showing an example of the structure of such a conventional seal ring. In this case, sliding holes 12 and 13 are cut through a stepped portion 11 in the sliding contact portion of the valve body with the ball. An annular seat retainer 15, which is always urged in the direction of the ball 2 by a spring 14, is mounted in the sliding hole 13 so as to be slidable in the direction of the valve axis shown by an arrow 16. There is.

Reference numeral 17 denotes an O-ring for sealing, and an annular seat ring 18 made of synthetic rubber or the like is attached to the tip of the seat retainer 15.
The outer annular portion 22 of the seat ring 18 and the seat retainer 15 is provided between the claw 20 of the outer ring 19 slidably attached to the outer ring 2 and the outer ring 21 bolted to the outer ring.
The seat ring 18 is fixed to the seat retainer 15 by sandwiching the seat ring 18.

Therefore, the seat ring 18, outer ring 19, settling ring 21 and seat retainer 15
are integrally slidable in the axial direction within the sliding holes 12 and 13, and the seat surface 23 of the seat ring 18 is pressed against the surface 24 of the ball 2 by the pressing force of the spring 14. .

When the valve is fully open or the ball 2 is rotating as shown in Fig. 2, the upstream pressure P ₁ and the downstream pressure P ₂ are equal, so
As shown in the figure, a gap 26 exists between the contact surface 25 of the seat retainer 15 facing the balls 2 and the surface of the balls 2. Therefore, ball 2
When it is rotated 90 degrees from the state shown in the figure to bring it into a fully closed state, the upstream pressure P ₁ becomes greater than the downstream pressure P ₂ , and the seat retainer 15 is pushed in the direction of the arrow 27 by the differential pressure. , the contact surface 25 of the seat retainer 15 contacts the surface 24 of the ball 2, and the gap 26 becomes zero.

In this way, the seat retainer 15 slides in the direction of the arrow 16 depending on the upstream and downstream pressure conditions, and especially in the fully closed state, the gap 26 becomes 0, so the sealing condition is significantly improved. However, when the ball is fully opened or when the ball is rotating, when no differential pressure is generated, the gap 26 is created as described above, so foreign matter adhering to the ball 2 enters the gap 26 and is moved to the seat surface 23 by the rotation of the ball 2. This can lead to sheet leakage.

Problems with conventional technology The third method was developed to eliminate these drawbacks.
A wiper 27 shown in the figure, the wiper 27
The wiper is made of a ring-shaped synthetic resin or the like that is fitted and fixed in a groove 29 bored in the surface 28 of the seat retainer 15 facing the balls 2. Since such a wiper is also a fixed type, the valve is not attached to the wiper. When the wiper 27 is fully closed, there must be a gap 26' between the wiper 27 and the ball 2, which is about the same as the gap 26 between the contact surface 25 of the seat retainer 15 and the surface of the ball 2. Therefore, such a fixed type wiper does not function as a wiper against foreign matter smaller than the gap 26', and there is a problem in that sheet leakage occurs if the wiper and the ball surface are constantly in contact with each other.

Purpose of the invention In order to solve the above-mentioned problems, the present invention makes the wiper movable so that it can be moved even when the seat retainer moves or the wiper itself is worn out.
The purpose of this is to keep the ball surface in constant contact with an appropriate pressure and prevent foreign matter attached to the ball surface from getting around to the seat surface, thereby preventing seat leakage.

Structure of the Invention The gist of the means adopted by the present invention to achieve the above object is to provide a seat retainer that is slidable in the valve axis direction in the sealing portion between the valve body and the ball. A first elastic member is interposed between the seat retainer and the valve body to elastically urge the seat retainer toward the ball, and the seat portion of the seat ring provided at the tip of the seat retainer is pressed against the ball to prevent leakage. In the ball valve, an annular groove is formed in the side surface of the seat retainer facing the ball, and a wiper that is slidable in the groove and a second wiper that presses the wiper against the ball surface are provided in the groove. At the same time, the force of the second elastic member and the seat ring to separate the seat retainer from the balls is set to be greater than the force of the first elastic member to press the seat retainer against the balls. This is a ball valve seal structure in which the seat ring and wiper are always in contact with the ball surface regardless of movement or wear of the wiper.

Example Next, we will explain the fourth example embodying the present invention.
This will be explained with reference to the accompanying drawings below.

Here, FIGS. 4a and 4b are side sectional views of a seal structure that is an embodiment of the present invention, and a is a fully opened ball;
Alternatively, it shows the state during rotation, and b shows the fully closed state. FIG. 5 is a side sectional view showing a modified example of the wiper, and FIG. 6 is a side sectional view showing a wiper fall prevention mechanism.

In the drawings, the same reference numerals are used for parts common to those shown in FIGS. 1 to 3.

In FIG. 4a, reference numeral 18 denotes a seat ring for pressing the seat surface 23 against the surface 24 of the ball 2 to prevent leakage, as described above.
An outer ring 19 and a set ring 2 are attached by bolts to the tip of a seat retainer 15 which is slidable in the axial direction in a sliding hole 13 cut in the seat retainer 15.
The seat surface 23 is always fixed to the surface of the ball 2 by the pressing force of the compression spring 14, which is an example of a first elastic member compressed between the valve body 3 and the seat retainer 15. 24 is pressed.

An annular groove 31 is carved all around the side surface 30 of the seat retainer 15 facing the balls, and a second elastic member having a U-shaped cross section is formed in the inner part 35 of the groove 31. A type of spring 32 is attached to the outlet side of the groove 31.
An annular wiper 33 is mounted in contact with the groove 31 and slidable in the axial direction of the groove 31.

The wiper 33 is pressed by the spring 32 and is set to be in close contact with the surface 24 of the ball 2 at all times.
4 is formed in a tapered shape so as to follow the surface shape of the ball 2.

FIG. 4b shows the fully closed state of the valve, and the seat retainer slides in the direction of the ball 2 due to the differential pressure between the upstream pressure _P1 and the downstream pressure _P2 , and the ball of the seat retainer 15 The contact surface 30 on the second side is shown in contact with the ball 2. In this way, the seat retainer 15 must be able to freely slide left and right between the state shown in FIG. 4 a and the state shown in FIG. 4 b. Dimensions of part 35 and spring 3
The dimension 2 must be such that the movement allowance of the seat retainer 15 can be absorbed.

Further, when the upstream pressure P ₁ and the downstream pressure P ₂ are approximately equal, that is, when the valve is open or the valve is rotating, the seat retainer 15 moves in the upstream direction,
Conversely, when the valve is fully closed, that is, when the upstream pressure P ₁ becomes greater than the downstream pressure P ₂ , the differential pressure and the force of the spring 14 cause the valve to move downstream. That is, in this case, the movement range of the wiper 33 is the difference between the width of the deep bottom part 35 of the groove 31 and the width of the U-shaped spring 32, as is clear from the figure. It must be wider than the gap 26 between the surface 24 and the surface 24.

Next, the operation of the above embodiment will be explained.
In the state shown in FIG. 4a, in which the balls are fully open or rotated, the upstream pressure P ₁ and the downstream pressure P ₂ are equal, so the force that presses the seat retainer 15 toward the ball is the force that pushes the seat retainer 15 upstream. This is the difference between the elastic force of the seat ring 18 and the force of the spring 32 that try to press the seat retainer 15 in the downstream direction, and the pressing force of the spring 14 that tries to press the seat retainer 15 downstream against the balls 2.
Since the force is set to be weaker, the seat retainer 15 moves upstream, and a gap 26 exists between the pressing surface 30 of the seat retainer and the surface 24 of the ball, and the seat ring 18 Seat surface 2
3 is pressed against the surface 24 of the ball 2, and at the same time, the wiper 33 housed in the groove 31 is urged toward the ball 2 by the spring 32, and the contact surface 34 at the tip thereof is pressed against the surface 24 of the ball 2. come into contact with
Foreign matter that has entered the gap 26 may be removed from the seat surface 23.
prevent it from entering.

In this state, if the ball is fully closed as shown in Figure 4b, the upstream pressure P ₁ will be the downstream pressure
_P2 , and the resultant force of the differential pressure and the force of the spring 14 causes the seat retainer 15 to move toward the ball 2.
The seat retainer 15 moves until the contact surface 30 of the seat retainer 15 contacts the surface 24 of the ball 2 . Therefore, the wiper 33 is pushed by the surface 24 of the ball 2 and moves relatively within the groove 31 in the direction opposite to the ball 2, and the U-shaped spring 32 is moved as shown in FIG.
The wiper 33 is deformed by the amount of movement as shown in FIG.

In this way, the wiper 33 is always in contact with the surface 24 of the ball 2 with a force corresponding to the elastic force of the spring 32, regardless of the sliding state of the seat retainer 15, so that foreign matter attached to the surface of the ball 2 can be removed. Before reaching the sheet surface 23, it is wiped off and removed by a wiper 33.

The wiper 33 wears out quickly due to foreign substances such as slurry, but as described above, the wiper 33 is slidable relative to the seat retainer 15 and is always elastically biased against the surface of the ball 2. So,
Despite the wear of wiper 33, wiper 3
The sliding contact surface 3 is always pressed against the surface of the ball 2, so that the function of wiping off foreign matter is not deteriorated.

In this way, the wiper of the present invention is not fixed and contacts the ball with an arbitrary surface pressure depending on the elastic force of the spring 32, so no excessive surface pressure is applied to the contact surface between the wiper and the ball. , the material of the wiper can be freely selected.

Therefore, it is possible to use metal as the material for the wiper, and when metal is used, there is no risk of it sagging like with synthetic resin, so its shape is stable for a long time, and it can be formed into any shape. can be selected.

For example, as shown in FIG. 5, the contact portion of the wiper 33' with the surface of the ball 2 is formed into an acute angle,
It is also possible to enhance the effect of wiping foreign matter on the ball surface by the wiper 33'.

In addition, the wiper 33 can take various forms regardless of the shape described above, and the elastic member that presses the wiper in the direction of the ball is not limited to the above-mentioned U-shaped spring. It is possible to use elastic members having a V-shaped cross section, a wave shape, and various other shapes.

Further, the wiper 33 is always urged outward of the groove 31 by the elastic member 32. Therefore, when assembling the valve, it is desirable to fix the wiper 33 in the groove 31 against the elastic force of the elastic member 32.

For this purpose, a set bolt 38 is attached to a threaded portion 37 formed on the inner surface 36 of the seat retainer 15.
The wiper 33 is prevented from falling off by screwing it in, drilling an insertion hole 39 for the set bolt at a position on the wiper side corresponding to the position of the set bolt, and protruding the set bolt into the insertion hole. This makes assembly of the valve extremely easy. If the size of the insertion hole 39 is made larger than the amount of sliding in the sliding direction with respect to the set bolt 38,
The set bolt can be left in place.

Effects of the Invention As described above, in the present invention, a seat retainer that is slidable in the valve axis direction is provided at the sealing portion between the valve body and the ball, and a seat retainer is provided between the seat retainer and the valve body. In a ball valve that includes a first elastic member that elastically biases the seat retainer toward the ball, and presses the seat portion of the seat ring provided at the tip of the seat retainer against the ball to prevent leakage, the seat retainer An annular groove is formed in the side surface facing the ball, and a wiper that is slidable in the groove and a second elastic member that presses the wiper against the ball surface are installed in the groove, and the above-mentioned The force with which the second elastic member and the seat ring separate the seat retainer from the balls is set to be larger than the force with which the first elastic member presses the seat retainer against the balls, and the force with which the seat retainer is moved away from the balls is set to be greater than the force with which the first elastic member presses the seat retainer against the balls. Regardless of the situation, the seal structure of the ball valve is such that the seat ring and wiper are always in contact with the ball surface, so the wiper is always in contact with the ball surface with an appropriate pressing force, and the ball surface is kept in contact with the ball surface. Since attached foreign matter does not reach the seat surface, there is less damage to the seat surface, and its lifespan is extremely long.In addition, since the material and shape of the wiper can be selected arbitrarily, the wiper's effectiveness in wiping away foreign matter is improved. This has various effects such as reducing the change over time.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a conventional general ball valve, Figures 2 and 3 are side sectional views of the sealing part of the same ball valve, and Figures 4a and b are an embodiment of the present invention. FIG. 5 is a side sectional view showing a modified example of the wiper that can be used in the same embodiment; FIG. 6 is a side sectional view showing the wiper's falling-off prevention structure. . Explanation of symbols, 2... Ball, 3... Valve body, 9... Seal portion, 15... Seat retainer, 18... Seat ring, 23... Seat surface (seat portion), 30... Contact surface, 31...groove, 32
...Elastic member (U-shaped spring), 33,3
3'...Wiper.

Claims (1)

[Claims for Utility Model Registration] 1. A seat retainer that is slidable in the direction of the valve axis is provided in the seal between the valve body and the ball, and a seat retainer is provided between the seat retainer and the valve body in the direction of the ball. In a ball valve in which a first elastic member that is elastically biased is interposed and the seat portion of a seat ring provided at the tip of the seat retainer is pressed against the ball to prevent leakage, the side surface of the seat retainer facing the ball is An annular groove is bored, and a wiper that is slidable in the groove and a second elastic member that presses the wiper against the ball surface are installed in the groove, and the first elastic member is The force with which the second elastic member and the seat ring separate the seat retainer from the balls is set to be greater than the force that presses the seat retainer against the balls, so that the seat ring A ball valve seal structure characterized in that the wiper and the wiper are always in contact with the ball surface. 2. The seal structure described in claim 1 of the utility model registration, in which the wiper is made of metal. 3. The seal structure described in claim 1 of the utility model registration claim, in which the elastic member has a U-shaped or V-shaped cross section. 4. The seal structure according to claim 1 of the utility model registration, in which the contact portion with the wiper ball surface is formed at an acute angle. 5. The scope of the utility model registration claim, in which the seat retainer is carved with a threaded portion that opens toward the groove, and the wiper is provided with a hole for inserting the tip of a set bolt screwed into the threaded portion. Seal structure described in Section 1.