JPH08219325A - Electro-static charge preventing type ball valve - Google Patents

Abstract

PURPOSE: To provide an electro-static charge preventing type ball valve which is of simple construction, easy to assemble, and capable of securely removing the electric charge. CONSTITUTION: The upper end 10b of a spring is allowed to elastically and springily abut on the inner face 2d of a body 2, while the lower end 10c is allowed to elastically and springily abut on the peripheral surface 3c of a recessed groove 3a of a ball 3, and further, the reduced diameter part 10a formed in the middle part of the spring is fitted on the lower end part 4a of a stem. Thus, the body 2, the ball 3, the stem 4 are electrically triggered into conduction, and the electric charge generated on the ball 3 or the stem 4 is not charged in the ball valve body to be quickly escaped to the body 2 and grounded. Since static electricity is discharged in the ball valve body, combustible fluid flowing in the ball valve body is not ignited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge for preventing fire or explosion of a controlled fluid due to discharge of static electricity by promptly releasing static electricity charged on a ball or a stem which is a valve body to the valve body. Preventive ball valve.

[0002]

2. Description of the Related Art A conventional floating ball valve has a ball, which is a valve body, sandwiched between a pair of seat rings, and is internally mounted in the valve body. When mounted on the body, it is supported by thrust washers, stem bearings and gland packing. The seat ring, thrust washer, stem bearing, and gland packing are made of electrically insulating polymer material such as PTFE. It is in an electrically floating state.

When a ball valve having such a structure is provided on a pipe to control a fluid, the ball is electrically charged by friction when the fluid passes through the ball, which is a valve body, but a seat ring that holds the ball is used. The electric charge generated on the ball as an insulator cannot escape to the valve body, and this electric charge is charged to the ball and the stem as static electricity. For this reason, when the static electricity charged on the ball or stem rises above a certain potential, discharge will occur in the bulb. In particular, when the fluid flowing in the valve is a flammable fluid such as gas, oil, chemicals, etc., the spark generated during discharge may ignite the fluid and cause a serious accident such as fire or explosion.

In order to prevent such a situation, it is necessary to promptly release the electric charge generated in the ball to the valve body and ground it. Although various means for preventing static electricity from entering the ball valve have been proposed, for example, there is a ball valve 20 having a structure as shown in FIG. This is a pair of seat rings 22 inside the valve body 21,
The ball-shaped ball 23 is held by 22 and the valve body 2
The ball 24 is formed by the stem 24 provided in the first stem hole 21a.
3 is configured to be rotatable. The stem 24 is provided with an antistatic mechanism 25.

The antistatic mechanism 25 includes a joint between the ball 23 and the stem 24, the stem 24 and the valve body 21.
It is necessary to provide each of them at each of the joint portions, and as shown in FIG. 9A, two antistatic mechanisms 25, 25 are required. As shown in FIG. 9 (b), the specific structure of the antistatic mechanism 25 is as follows: a conductive contact 27 elastically urged by a conductive spring 26 is provided in a charging hole 24 a formed in the stem 24. When the ball valve 20 is assembled, the ball 23, the stem 24, and the valve body 21 are electrically connected to each other through the spring 26 and the contact 27 when the ball valve 20 is assembled.
It is configured so that the electric charge generated in 3 is released to the valve body 21.

[0006]

However, as is apparent from the above-mentioned structure, the antistatic mechanism 25 has a large number of parts, and a mechanism having an elastically urging member such as the spring 26 takes time and effort to assemble. Therefore, there is a problem in that the assembly process is complicated and an increase in cost cannot be avoided. Moreover, such a ball valve 20 has been used for many years, and the seat ring 22, the thrust washer 28, the stem bearing 29, the gland packing 30 are used.
It is necessary to replace consumable parts, and the ball valve 20 is disassembled during such maintenance work.

In this case, the spring 2 forming the antistatic mechanism 25
Since 6 and the contactor 27 are relatively small parts, when the ball valve 20 is reassembled after maintenance, these parts 26 and 27 are often left unassembled. Further, when the ball valve 20 is disassembled, the contact element 27 pops out together with the spring 26 from the charging hole 24a formed in the stem 24, and these members 26, 27
It often happens that you lose your. When such a situation occurs, the antistatic mechanism 25 cannot function normally, which may cause an unexpected accident.

Further, as shown in FIG. 9 (b), the caulking portion 24b is formed at the opening end of the charging hole 24a formed in the stem 24.
By forming the above, it is possible to prevent the spring 26 and the contactor 27 from protruding and forgetting to assemble during the reassembly, but the number of parts is still large, the assembly process is complicated,
Various problems such as high cost have not been solved. The present invention has been developed in view of such problems of the conventional example, and an object thereof is to have a simple configuration, easy assembling, and surely removing electrostatic charge. The present invention provides an antistatic ball valve capable of

[0009]

In order to achieve the above object, in a ball valve in which a ball having a through hole in a body is provided so as to be freely opened and closed by rotating the stem, the lower end of the above-mentioned stem is located above the ball. The upper end of the spring fitted in the lower end of the stem is abutted on the inner surface of the body, the lower end is abutted on the peripheral surface of the groove of the ball, and is provided in the middle of the spring. The configuration is characterized in that the reduced diameter portion is fitted in the middle of the lower end portion of the stem.

In this case, it is preferable that the inner diameter of the reduced diameter portion is smaller than the diameter of the spring mounting surface at the lower end portion of the stem. Then, a locking groove is formed in the lower end portion of the stem in the middle of the spring mounting surface, and the reduced diameter portion of the spring is locked in the locking groove, or the reduced diameter portion of the spring is placed in the middle of the lower end portion of the stem. Welding is preferred.

[0011]

Since the antistatic ball valve of the present invention is constructed as described above, an electrically conductive state is formed from the ball, which is the valve body, to the body of the valve via the stem. In other words, the spring fitted in the lower end of the stem is elastically disposed in the cavity formed between the ball and the inner surface of the body in the ball valve, so that the upper end of the spring is aligned with the inner surface of the body. , The lower end is in contact with the peripheral surface of the groove on the upper part of the ball, and the reduced diameter part of the spring is fitted in the middle of the lower end part of the stem, so ensure the electrical connection from the ball to the body. You can In addition, since both ends of the spring come into contact with the peripheral surface of the groove at the top of the ball and the inner surface of the body with a wide contact area, the electrical contact resistance of these is small, and regardless of the opening of the ball, it is always good. It is possible to secure a good conduction state.

As a result, even if the ball of the ball valve provided on the pipe is charged by the friction due to the passage of the fluid, the ball and the body of the valve are electrically connected to each other via the stem and the spring. The ball and stem are not charged, and the electric charge generated in the ball is immediately released to the valve body and grounded.
Further, even if the stem is charged by the friction caused by the rotation of the stem, the charge generated in the stem is immediately released to the body of the valve via the spring and is grounded. Therefore, static electricity is never discharged in the valve, and the flammable fluid flowing in the valve can be safely controlled.

Further, since the static electricity prevention type ball valve of the present invention has a simple structure in which only one spring is added to a normal floating type ball valve, it is easy to assemble in the manufacturing process, and it is useless. There is no increase in cost. In addition, the conventional product can be used. Further, even if the ball valve is disassembled at the time of maintenance, the spring is fitted to the lower end of the stem so that it does not suddenly pop out and be lost. Moreover, since the above-mentioned spring is not a small member as seen in the conventional example, there is no fear of forgetting to incorporate it when reassembling.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an antistatic ball valve according to the present invention will be described in detail with reference to the drawings. The ball valve body 1 of the present embodiment is basically based on a normal floating type ball valve. FIG. 1 shows that, for example, a body 2 of a valve having a two-piece structure is provided with a fluid inlet 2a, a fluid outlet 2b, and a stem hole 2c, and a ball 3 as a valve body is rotated in the stem hole 2c. The stem 4 is provided, and the ball 3 described above is held in the body 2 by a pair of seat rings 5, 5.

In this case, a thrust washer 6, a stem bearing 7 and a gland packing 8 are appropriately provided in the stem hole 2c in which the stem 4 is provided, and the stem 4 has a lower end portion 4a for rotating the ball 3 and a stem. A flange portion 4b for preventing popping out is formed, and a handle 9 for opening and closing the ball 3 is provided at the upper end portion of the stem 4. In addition, a concave groove 3a into which the lower end portion 4a of the stem 4 is fitted and locked is formed in the upper portion of the ball 3, and a through hole 3b through which a fluid flows is formed substantially in the center portion.

The ball valve body 1 thus constructed
As shown in FIGS. 2 and 3, a cavity 2e is formed between the upper portion of the ball 3 and the inner surface 2d of the body 2. In the cavity 2e, as shown in FIG.
A spring 10 having a diameter-reduced portion 10a at an intermediate position is provided. The reduced diameter portion 10a of the spring 10 is slightly smaller than the diameter of the spring mounting surface 4c in order to be able to be fitted to the spring mounting surface 4c of the stem lower end portion 4a. Further, on the inner surface 2d of the body 2, a step portion 2f is formed around the stem hole 2c in order to improve the contact property of the spring 10.

As shown in FIG. 4, the reduced diameter portion 10a of the spring 10 is connected to the spring mounting surface 4 of the stem lower end portion 4a.
With the stem 4 fitted in the c, the stem 4 is attached to the stem hole 2 of the body 2.
By assembling the ball valve main body 1 provided in c, the upper end 10b of the spring 10 slidably contacts the inner surface 2d of the body 2 and the lower end 10c of the spring 10
Is elastically brought into contact with the peripheral surface 3c of the concave groove 3a of the ball 3 to electrically connect the members of the body 2, the ball 3 and the stem 4 to each other.

In this case, as shown in FIG. 5, a locking groove 4d is formed on a side surface of the lower end portion 4a of the stem at an intermediate position of the spring mounting surface 4c, and the spring 10 is fitted in the locking groove 4d.
The reduced diameter portion 10a of the spring 10 may be fitted, or, as shown in FIG. 6, the reduced diameter portion 10a of the spring 10 is fitted to the spring mounting surface 4c of the stem lower end portion 4a, and this portion is spotted. By welding 4e, the conductivity between the members 2, 3 and 4 can be made more reliable. Further, as shown in FIG. 8, the small-diameter portion 11b of the two springs 11, 11 including the large-diameter portion 11a and the small-diameter portion 11b,
The spring 10 can be obtained by stacking 11b on each other.

The ball valve body 1 of this embodiment is made of metal such as stainless steel, bronze, cast iron, etc. for the body 2, ball 3 and stem 4, and the spring 10 fitted to the lower end 4a of the stem 4 is also made of metal. Things are used. In this case, in order to eliminate the potential difference between the different metals, the spring 10
It is preferable to use the same metal as the ball 3 and the stem 4. The present invention can be applied to the ball valve body 1 having a one-piece structure or a two-piece structure, and can also be applied to a gas plug having a conical or cylindrical valve body.

Next, the operation of this embodiment will be described. Since the electrostatic antistatic ball valve of this embodiment is configured as described above, an electrically conductive state is formed from the ball 3 which is the valve body to the body 2 of the valve via the stem 4. That is, the spring 10 that electrically short-circuits these members 2, 3 and 4 is elastically arranged in the cavity 2e formed between the ball 3 and the inner surface 2d of the body 2 in the ball valve body 1. Since the upper end 10b of the spring 10 abuts on the inner surface 2d of the body 2, the lower end 10c abuts on the peripheral surface 3c of the groove 3a of the ball 3, and the reduced diameter portion 10a of the spring 10 is a stem lower end portion. Since it is fitted to the spring mounting surface 4c of 4a,
It is possible to secure the electrical connection from the ball 3 to the body 2 of the valve.

In addition, the peripheral surface 3c of the concave groove 3a of the ball 3
Also, since the upper and lower ends 10b, 10c of the spring 10 come into contact with the stepped portion 2f formed on the inner surface 2d of the body 2 with a large contact area, respectively, the electrical contact resistance is small, and the ball 3 is always good regardless of the opening degree. A good electrical continuity is secured. Further, since the spring 10 is urged in the thrust direction of the stem 4, the opening and closing of the ball 3 is not hindered, the turning torque is not excessively increased, and the ball 3 is opened and closed smoothly. be able to.

As a result, even if the ball 3 of the ball valve body 1 provided on a pipe (not shown) is charged by friction due to passage of fluid, the ball 3 and the body 2 are electrically connected via the stem 4 and the spring 10. Since the ball 3 and the stem 4 are not electrically charged, the electric charge generated in the ball 3 is immediately released to the valve body 2 and grounded. Further, even if the stem 4 is charged by the friction caused by the rotation of the stem 4, the charge generated in the stem 4 is immediately released to the valve body 2 via the spring 10 and is grounded. Therefore, there is no discharge of static electricity in the ball valve body 1,
The combustible fluid flowing in the ball valve body 1 can be safely controlled.

In addition, in the ball valve of the antistatic type of this embodiment, one spring 10 is provided in the ball valve body 1.
Since it has a simple structure with only the addition of, the assembling in the manufacturing process is simple and the cost is not increased. Further, the ball valve body 1 can be used as a conventional product, so that it is inexpensive. Further, even if the ball valve body 1 is disassembled during maintenance, the spring 10 is fitted to the spring mounting surface 4c of the stem lower end portion 4a, so that it does not unexpectedly pop out and be lost. Moreover, since the spring 10 is not a small member as in the conventional example, and is a member having a unique shape, it is highly recognizable to the operator and there is a risk of forgetting to assemble it when reassembling. Absent.

[0024]

As is apparent from the above description, in the antistatic ball valve of the present invention, a spring having a reduced diameter portion is disposed midway between the ball upper portion of the ball valve and the inner surface of the body, The reduced diameter portion of this spring is fitted to the lower end of the stem, the upper end of the spring is brought into contact with the inner surface of the body, and the lower end is brought into contact with the upper portion of the ball. Even if the ball and body are electrically charged through the stem and spring even if they are charged by the friction due to, the ball and stem are not charged, and the charge generated on them is immediately transferred to the valve body. Can be escaped and grounded.

As a result, static electricity is never charged in the ball valve, the combustible fluid flowing in the ball valve is not ignited by the discharge due to static electricity, and the control of these fluids can always be performed safely. it can. Moreover, since the present invention has a simple structure with a small number of essential components, it is possible to simplify the assembly,
Products can be provided at low cost. Further, since the spring having the reduced diameter part in the middle is fitted to the lower end part of the stem, it does not suddenly pop out and is lost, so the maintainability is high, and high reliability can be maintained for a long period of time. .

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is an enlarged view of a main part as seen from the side surface in FIG.

FIG. 4 is a diagram showing a method of fitting a spring to the lower end portion of the stem in FIG.

FIG. 5 is a view showing a method of fitting a spring to a lower end portion of a stem in which a spring locking groove is formed.

FIG. 6 is a view showing a state in which a reduced diameter portion of a spring is spot-welded to a lower end portion of a stem.

FIG. 7 is a view showing the shape of an embodiment of the spring in FIG.

FIG. 8 is a diagram showing the configuration of another example of a spring.

FIG. 9 is a cross-sectional view showing a structure of a ball valve having a conventional antistatic mechanism and an enlarged view of a main part.

[Explanation of symbols]

 2 body 2d body inner surface 3 ball 3a concave groove 3b through hole 3c peripheral surface 4 stem 4a stem lower end portion 4c spring mounting surface 4d locking groove 10 spring 10a reduced diameter portion 10b spring upper end 10c spring lower end

Claims (4)

[Claims] 1. A ball valve in which a ball having a through hole in a body is provided so as to be freely opened and closed by rotating a stem, and the lower end of the stem is fitted and locked in a groove formed in the upper portion of the ball. , The upper end of the spring fitted in the lower end of the stem is in contact with the inner surface of the body, the lower end is in contact with the peripheral surface of the groove of the ball, and the reduced diameter portion provided in the middle of the spring is fitted in the middle of the lower end of the stem. An antistatic ball valve characterized by being worn. 2. The antistatic ball valve according to claim 1, wherein the inner diameter of the reduced diameter portion is smaller than the diameter of the spring mounting surface of the lower end portion of the stem. 3. The antistatic ball according to claim 1, wherein a locking groove is formed in the lower end of the stem in the middle of the spring mounting surface, and the reduced diameter portion of the spring is locked in the locking groove. valve. 4. The antistatic ball valve according to claim 1, wherein the reduced diameter portion of the spring is spot-welded in the middle of the lower end portion of the stem.