JP2671763B2 - Ball valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a ball valve, and more particularly to a cartridge type ball valve in which a valve ball portion can be attached to and detached from a valve body, which can be used at high temperature and can be operated remotely. Ball valve suitable for.

[0002]

2. Description of the Related Art Generally, a ball valve has a structure in which a ball having a fluid passage hole is fastened with a ball seat to rotate the ball so as to prevent or allow passage of a fluid. In order to obtain a sufficient sealing property, it is necessary that the material of the ball sheet is soft and conforms well to the surface of the ball and adheres closely. In addition to this flexibility, it is also desirable that the sheet has a good processability, and heat resistance and acid resistance are required depending on the use conditions. Conventionally, fluororesin has been favorably used as a sheet material having these properties and excellent in abrasion resistance. However, the heat resistance of the fluororesin is limited to about 150 ° C. In the environment where it is exposed to radiation, the usable limit is lower than this.

[0003] Under such usage conditions that high temperature resistance or radiation resistance is added thereto, polyether ether ketone (PEE), which is a kind of engineering plastic, is used.
K) It has been known that resins can withstand. However, this material has strength similar to steel, is hard, and lacks the flexibility of Teflon.Therefore, when it is used as a ball valve ball seat, it must be tightened sufficiently to obtain a sufficient sealing effect. Farewell. Then, the torque required to rotate the ball becomes abnormally high, which makes it practically difficult to rotate the ball. Such a valve is
Especially, it is unsuitable for remote operation by an actuator.

On the other hand, as a valve suitable for handling radioactive materials, the applicants have already developed a cartridge type valve part which is detachable from the valve body (Japanese Patent Publication No. 59-11791). It was put to practical use. In the ball valve which is a typical embodiment of this cartridge type valve, even when the above PEEK resin is used for the ball seat, the above-mentioned difficulty of ball rotation does not change. In addition, the seal between the cartridge and the valve body should also meet the conditions of high temperature resistance and radiation resistance.
Although it is necessary to use EEK resin, the problem that it is difficult to secure a seal extends to this.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide the above-mentioned cartridge type ball valve with high temperature resistance and radiation resistance, so that a hard engineering plastic such as PEEK resin is used as a material for the ball seat and the gasket. The purpose of the present invention is to provide a ball valve which is easy to operate because it requires a low rotational torque of the ball while ensuring sufficient sealing property.

[0006]

The ball valve of the present invention which achieves the above object is, as shown in FIG. 1 in its entirety, a cylindrical valve body (1) having a bottomed cylindrical fluid passage hole. A cartridge (2) having a valve is detachably provided, a valve ball (3) having a fluid passage hole is rotatably accommodated in the cartridge, and the pair of balls are arranged in the cartridge on both sides in the flow direction. Seat (4,4)
And a pair of gaskets (5, 5) arranged between the cartridge and the valve body on both sides in the flow direction.
In the ball valve sealed in 5), the ball seat and the gasket are made of engineering plastic, and the ball seat (4, 4) is a ring-shaped body having a V-shaped cross section that is open to the outside at least on the side in contact with the ball. The gasket (5, 5) is a ball valve characterized by being a ring-shaped body having a V-shaped or U-shaped groove on the side in contact with the cartridge.

The shape of the ball seat (4) is a ring (4A) having a V-shaped cross section as shown in FIG. 2, or a ball contact side having a V-shaped cross section and a straight side contacting the cartridge as shown in FIG. Any of the rings (4B) having a uniform cross section and a hook-shaped cross section as a whole may be used.

In both cases, as shown in detail in FIGS. 3 and 5, it is preferable that the ball contact side of the ball seat has a bent roof-shaped cross section, and the inclination of the fluid passage hole with respect to the axis is at the center. It is recommended to select in the range of 45 ± 5 ° on the side (41) and 60 ± 5 ° on the side (42).

As a typical shape of the gasket (5), as shown in FIG. 6, a gasket (5A) having a V-shaped groove (51) on the side contacting with the cartridge is provided. In the example shown in FIG. 7, the groove has an opening angle of about 90 °, but it may be a U-shape having a narrower angle and a curved bottom.

In the example shown in FIG. 1, the cartridge (2)
One of the surfaces passing through the fluid passage hole has a taper inclining inward downward, and the inner shape of the valve body has a corresponding taper to fix the bonnet (6) to the valve body (1). By pushing the cartridge (2) downward, the left and right gaskets (5, 5)
A lateral force is applied to 5), and the structure is such that close contact is achieved. It is needless to say that a mechanism capable of applying an appropriate force may be provided so that a gasket (5) can be satisfactorily sealed between the valve body and the cartridge with other structures.

In order to tighten the ball seat (4) with respect to the balls (3) inside the cartridge, an adjuster (7) is used in the example shown in the drawing, and the externally cut male screw and the fluid passage hole of the cartridge (2). The adjustment is performed by advancing the adjuster (7) by meshing with the internally threaded female screw. The other mechanism can also be adopted, as described above regarding the close contact between the cartridge and the valve body.

[0012]

By forming the ball seat to have a V-shaped cross section in which the side in contact with the ball is open to the outside, the bottom of the V-shape of the ball seat is deformed when the ball is tightened, and acts like a spring. . As a result, the ball and the ball seat are in close contact with each other over the entire circumference, and a good seal can be achieved.

In a preferred embodiment in which the ball-contacting side of the ball seat is formed into a bent roof shape, the tip portion is further deformed at the boundary near the change of the inclination of the fluid passage hole with respect to the axis, and a two-stage spring structure is formed. The ball seat works as an object.

On the other hand, when the gasket is pressed toward the valve body, the contact surface is easily deformed due to the presence of the V-shaped or U-shaped groove, and good adhesion is realized.

[0015]

EXAMPLE A Rejuice ball valve having a nominal diameter of 50 A and having the structure shown in FIG. 1 and the ball seats of FIGS. 2 and 4 (having the sectional shapes of FIGS. 3 and 5 which are detailed views thereof). , The gasket of FIG. 6 made of PEEK resin was incorporated.

The ball valve was examined for leak resistance, balls and rotational torque. In the test, N ₂ gas was used and the pressure was 3 kg / cm ² G, and the presence / absence of leakage in the ball seat portion and the gasket portion was checked when the valve was closed, and the ball rotation torque was opened-intermediate- It was measured at 3 points near the closing point. The results are as shown in Table 1 below.

Table 1 Ball seat leak status Rotational torque (kgf · m) shape Ball seat part Gasket part when opening Intermediate closing point Hook type Very small amount Very small amount 200 300 550 to 650 V shape None None 250 to 350 150 250 Next For an example of a V-shaped ball seat with a sufficient ball rotation torque, the N ₂ gas pressure of 3 kg / cm ² G
Under these conditions, the closing-opening cycle was repeated 100 times, and the presence or absence of leakage and the value of the rotating torque at that time were recorded. Table 2 shows the results.

Table 2 Number of Opening and Closing Leakage Rotational Torque (kgf · m) Closed → Opened Open → Closed 10 None 250-300 200-200 20 None 300-350 350-250 30 None 250-300 250-300 50 None 300-300 250-300 100 None 400-200 250-300 For the ball valve that has been subjected to the above 100 opening / closing tests, a thermal cycle load is applied by passing water after passing steam, and the influence on the sealing property is examined. It was The cycle consists of flowing steam having a temperature of 164 ° C. and a pressure of 7 kg / cm ² G for about 1 minute, and then flowing water having a temperature of 25 to 50 ° C. for about 2 minutes (the passing amount is about 50 liters). A leak test was performed by applying an air pressure of 3 kg / cm ² G every 10 cycles.

It was investigated how the temperature of the surface of the pipe connected to the valve changes before and after passing steam, and how the surface temperature of the valve changes after water is circulated. The data are shown in Table 3 together with the results of the leak test and the easiness of rotation of the handle.

[0020] Table 3 Cycle pipe temperature (℃) before and after the valve handle leak temperature (℃) Rotation test 1 27 66 27 Smooth leakage No 10 49 74 54 Smooth leakage No 20 50 74 54 None Smooth leak 30 50 74 55 Smooth No leak 40 49 75 75 49 Smooth No leak 50 48 74 75 53 No leak No 60 49 74 50 50 No leak No 70 48 48 73 54 No smooth leak 80 49 74 74 52 No smooth leak 90 49 72 50 50 Smooth no leak 100 52 75 57 57 None 110 46 73 44 No smooth leak 120 50 75 75 50 No smooth leak

[0021]

According to the present invention, the material of the ball seat and the gasket in the cartridge type ball valve is P
Even if the engineering plastic such as EEK resin is used, it is possible to obtain a good sealing property between the ball and the ball seat and between the cartridge and the valve body without excessive tightening, by using an appropriate shape. As a result, it is possible to operate the valve that is free from the risk of leakage with a small rotational torque. Since the rotation torque is small, it can be easily rotated by the actuator and does not hinder the remote operation. It is also resistant to thermal cycling during operation.

Therefore, the ball valve of the present invention is used for a valve which is exposed to a high temperature or has a large temperature difference such that a fluid of a high temperature and a fluid of a low temperature act alternately, and in particular, a fluid such as a high level radioactive waste liquid is transported. It is suitable as a valve that constitutes a plant having a piping line.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing an entire structure of an example of a ball valve of the present invention.

FIG. 2 is a cross-sectional view showing the shape of one embodiment of a ball seat used in the ball valve of the present invention.

FIG. 3 is an end view showing details of a portion A in FIG.

FIG. 4 is a sectional view similar to FIG. 2 showing the shape of another embodiment of the ball seat used in the ball valve of the present invention.

5 is an end view showing details of a portion B in FIG.

FIG. 6 is a cross-sectional view showing the shape of one embodiment of the gasket used in the ball valve of the present invention, corresponding to FIGS. 2 and 3.

7 is an end view showing details of a portion C in FIG.

[Explanation of symbols]

 1 Valve body 2 Cartridge 3 Ball 4,4A, 4B Ball seat 5,5A Gasket 6 Bonnet 7 Adjuster

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuuji Kawashima 1-8-23 Oshima, Koto-ku, Tokyo (72) Inventor Koumi ▲ Noboru 159-3, Naganuma-cho, Sakae-ku, Yokohama-shi, Kanagawa (56) References Special Kaihei 5-42586 (JP, A) Actual opening Sho 48-7821 (JP, U) Actual opening Sho 56-47959 (JP, U) Actual opening Flat 1-141968 (JP, U) Actual opening Sho 64-771 ( JP, U) Actual development Sho 58-148367 (JP, U) Special public 59-11791 (JP, B2) Special public 48-30935 (JP, B1) Special public 47-3057 (JP, B1) Actual public 60-1321 (JP, Y2)

Claims (3)

(57) [Claims] 1. A cartridge having a bottomed tubular cylindrical body having a fluid passage hole is detachably provided in a box-shaped valve body, and a valve ball having a fluid passage hole is rotatably accommodated inside the cartridge. In the ball valve, in which the valve ball is sealed by a pair of ball seats arranged on both sides in the flow direction, and the space between the cartridge and the valve body is sealed by a pair of gaskets arranged on both sides in the flow direction. Also, the gasket is made of engineering plastic, the ball seat is a ring-shaped body having a V-shaped cross section that is open to the outside at least on the side in contact with the ball, and the gasket has a V-shaped or U-shaped groove on the side in contact with the cartridge. A ball valve characterized by being a ring-shaped body having a certain cross section. 2. The ball valve according to claim 1, wherein a polyether ether ketone (PEEK) resin is used as the engineering plastic. 3. The ball seat side of the ball seat has a bent roof shape and the inclination of the fluid passage hole with respect to the axis is 45 ± 5 ° toward the center and 60 ± 5 ° toward the periphery. The ball valve according to claim 1 or 2.