JPH0334521Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The invention consists of a main valve stem with one end of the drive side protruding outward, and a valve stem located opposite The present invention relates to a butterfly valve in which a valve body is rotatably supported by both valve stems, which are divided into two parts, and an auxiliary valve stem inserted into the auxiliary valve stem.The butterfly valve is widely used for fluid control, etc.

[Conventional technology]

Conventionally, in butterfly valves coated with corrosion-resistant and chemical-resistant non-metallic materials, as shown in Fig. 6,
a valve body 2 coated with a corrosion-resistant and chemical-resistant material 2a;
A valve stem 3 supported by a bearing 1a on the main body 1 is fixed via a taper bolt 7, and after the fixation, both ends of the taper bolt 7 are coated again with the corrosion-resistant and chemical-resistant material 2a. The need arose.
In addition, in the figure, 4 is a seat ring.

However, in the above-mentioned case, if the final covering repair after driving the taper bolt 7 is not securely connected to the first covering material 2a, fluid will penetrate through this joint and cause a seal failure, resulting in damage to cast iron, ductile cast iron, etc. Valve body 2 made of non-corrosion-resistant and chemical-resistant material
There was a risk that the base material would be corroded and quality assurance could not be ensured.

Therefore, as shown in Fig. 4, the valve stem is divided into two vertically into a main valve stem 3A and an auxiliary valve stem 3B, and one of the divided drive-side main valve stems 3A is inserted into the valve body hole 2b. In some valve stems, the inner end of the valve stem is formed into a square shaft 3a, and the hole end on the valve body side is also made into a square hole, thereby integrating the valve body 2 and the valve stem 3A. Note that the sub-valve rod 3B is rotatably supported by the round hole of the valve body.

This eliminates the need for recoating as in the prior art example (FIG. 6), and also eliminates the risk of fluid penetration from the tapered bolt joint.

[Problem that the invention attempts to solve]

In the conventional butterfly valve described above, in which the valve stem is divided into upper and lower halves, when the valve stem is inserted into the valve body hole from each direction for coupling with the valve body, the drive side Air is trapped and compressed in the square hole of the valve body into which the main valve stem is inserted and the round hole of the valve body into which the auxiliary valve stem on the non-drive side is inserted.For example, in the round hole of the valve body on the non-drive side, Figure 5a
As shown in ~c, as the lower valve stem 3B is inserted into the valve body hole 2b of the valve body 2, the valve body hole 2
Air in b (indicated by crossed diagonal lines)2
There was a problem in that the valve stem 3B could not be inserted to the predetermined position shown in c in the figure because c was compressed.

The technical problem of the present invention is to provide a valve stem that is divided into upper and lower halves, which is easy to assemble and process, and which also prevents external leakage even if the primary seal between the valve body and the seat ring is destroyed.

[Means for solving problems]

In order to solve the problems and technical problems of the prior art described above, the present invention provides a butterfly valve equipped with a two-part valve stem, which is inserted into two valve body holes in the periphery of the valve body. At least one of the divided valve stems is composed of a core rod having an air vent groove on its circumferential surface and a cylindrical body tightly fitted to the core rod, and a sealing mechanism is provided in the air vent groove. It is characterized by having the following.

In addition, in implementation, it is desirable to use a check valve in the sealing mechanism.

[Effect]

Since the present invention is constructed as described above, when inserting (fitting) the divided valve stem into the valve body hole from the outside of the valve body, just like inserting a piston into a cylinder. The air trapped between the inner end of both valve stems and the valve body hole passes through an air vent groove and a seal mechanism on the circumferential surface of the core rod, which is tightly fitted into the cylindrical body that forms part of the valve stem. Excluded to the outside. Therefore, the valve stem is placed at a predetermined position in the valve body hole (usually
can be easily inserted to the deepest part).

Further, since a sealing mechanism is provided at an appropriate position in the air vent groove, even if fluid leaks from the primary seal portion during use of the valve, the sealing mechanism prevents external leakage.

In addition, in the case where the air vent grooves are provided on each divided valve stem, the air is removed from the valve body hole through the respective air vent grooves, and the air vent grooves are also separated. In the case of a valve provided only in one valve stem, the air trapped in the other valve body hole passes through the appropriate passage provided in the valve body and is mixed with the air in the one valve body hole. After that, it is expelled to the outside through the air vent groove of one of the valve stems.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view showing the lower half of a butterfly valve showing an embodiment of the present invention, and in the figure, the fourth
The same reference numerals as those shown in the figures and FIG. 5 indicate the same or similar parts.

In the figure, a main body (lower half from the center line is shown) 1 includes a valve body 2, which is divided into upper and lower halves, a main valve stem and a sub-valve stem (only the lower sub-valve stem 3B is shown in the figure). ) is rotatably supported by
As clearly shown in FIGS. 2 and 3, the sub-valve rod 3B is shrink-fitted to a core rod 32 having an air vent groove 31 along its circumferential surface in the axial direction of the valve rod. A hollow cylindrical body (sleeve) 33 is inserted and fitted in the direction of arrow a in this state.

A ball valve 35 is located between the lower end of the air vent groove 31 and a passage 34 bored in the center of the bottom of the core rod 32, and is pressed toward the passage 34 by a coil spring 36. At this time, a sealing mechanism is provided that seals (blocks) the air vent groove 31. In the figure, 6 is a bottom cover, 7 is a thrust support rod which is screwed onto the bottom cover 6 so that the vertical position of the valve body 2 can be adjusted, 8 is a bearing, and 9 is an O-ring.

Although not shown, the main valve rod 3A (see FIG. 4) that supports the valve body 2 at its upper portion has a similar configuration.

With the structure described above, when inserting the upper and lower two-split valve stems 3A and 3B into the hole 2b of the valve body 2 when assembling the valve body, the primary seal between the valve body 2 and the seat ring 4 is The ball valve 35, which also serves as a check valve in case of damage, is pushed up using a special tool against the coil spring 36, and the air vent circuit consisting of the air vent groove 31 is opened. When the air in the confined space b inside the valve body hole 2b escapes to the outside through the air release groove 31, it is easy to insert both valve stems to the predetermined position in the valve body hole. It is easy to assemble.

In addition, in the event that fluid leaks into the valve stem from the primary seal between the valve body and the seat ring during use of the butterfly valve, the bottom cover 6 can be removed and the ball valve 35 can be removed from the passage 34 using a special tool. By pushing up with , the above leakage detection becomes possible.

According to this embodiment, the valve rods 3A and 3B, which are composed of the cylindrical body 33 and the core rod 32, the ball valve 35, and the coil spring 36 can be made of various combinations of materials depending on the fluid.

In addition, since the O-ring 9 allows fluid sealing even if leakage occurs from the primary seal, it is also possible to make the cylindrical body 33 of a corrosion-resistant material and to use a strong and inexpensive material for the core rod 32.

In addition, since the sealing mechanism is composed of a ball valve 35 pressed by a coil spring 36, the structure is not only simple, but also easy to prevent minute dust contained in the air from adhering to the ball surface. It falls off and maintains its sealing properties.

In the above-mentioned embodiment, a structure in which an air vent groove is provided in each of the two divided valve stems has been explained, but as partially shown in FIG. A passage 10 communicating between the valve stems 2b and 2b is bored, and when the valve is assembled, air in the valve body hole of the main valve stem is discharged through the communication passage 10 to the valve body hole 2b of the auxiliary valve stem 3B. It is also possible to do so.

In this way, the upper valve stem 3A on the driving side is not provided with an air release groove, so when detecting leakage, etc., it is convenient from the viewpoint of the surrounding situation of the valve device installed in the piping system. There is.

It is also possible to use a check valve other than a ball valve as the sealing mechanism provided in the air vent groove, and it goes without saying that the number of air vent grooves, the cross-sectional shape, etc. can also be changed in design.

[Effect of idea]

As explained above, according to the present invention, at least one of the two divided valve stems inserted into the two valve body holes around the valve body is connected to the air vent groove on the circumferential surface. The air vent includes a core rod and a cylindrical body tightly fitted to the core rod, and by providing a sealing mechanism in the air vent groove, the following effects can be achieved.

(i) When assembling the divided valve stems by inserting them into the valve body holes, the air trapped in these valve body holes can easily escape to the outside and eliminate air retention, so two split valve stems are used. can be easily inserted to a predetermined position within the valve body. Therefore, the number of assembly steps is reduced, and it is possible to avoid assembling and shipping the air compressed air due to unreasonable assembly.

Furthermore, since the valve body hole cannot be brought into a vacuum state during disassembly, the two divided valve stems can be easily taken out and disassembled.

(ii) Since the air vent groove is equipped with a sealing mechanism, even if fluid leaks from the primary seal when the valve is in use, the sealing mechanism will prevent it from leaking to the outside through the air vent groove. Ru. Further, by temporarily canceling the sealing action of the sealing mechanism, it is possible to detect the leakage from the outside.

(iii) By configuring the air release passage of the valve stem from the valve body hole with a groove formed on the circumferential surface of the core rod that is tightly fitted into the cylindrical body, the passage of air according to the amount of released air is achieved. Grooving of the cross-sectional area is easy, and there is only a slight decrease in the strength of the valve stem due to the groove machining, and the core rod and cylindrical body that make up the valve stem are made of various combinations of materials depending on the fluid used. It is possible to do so.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing the lower half of the butterfly valve showing an embodiment of the present invention, and Fig. 2 is a -
A cross-sectional view of the line, Figure 3 is an exploded perspective view of the valve stem,
Fig. 4 is a vertical cross-sectional view of a butterfly valve equipped with a two-part valve stem showing a conventional example, Figs. FIG. 1... Main body, 2... Valve body, 2b... Valve body hole,
3A... Main valve stem, 3B... Sub-valve stem, 31... Air vent groove, 32... Core rod, 33... Cylindrical body, 34...
...Passage, 35...Ball valve, 36...Coil spring, 4...Seat ring.

Claims (1)

[Claims for Utility Model Registration] 1. A seat ring is stretched over the inner peripheral surface of a hollow cylindrical main body made of a rigid material, and a main valve rod with one end of the driving side protruding outward is provided within the main body. In a butterfly valve in which a valve body is rotatably supported by two valve stems that are divided into two parts and a sub-valve stem inserted in opposite positions, two valve body holes are provided around the valve body. At least one of the two divided valve stems inserted into the valve stem is composed of a core rod having an air vent groove on its circumferential surface and a cylindrical body tightly fitted to the core rod, A two-part valve stem for a butterfly valve, characterized in that a sealing mechanism is provided in the air vent groove. 2. The two-part valve stem of a butterfly valve according to claim 1, wherein the sealing mechanism is constituted by a ball valve pressed by a coil spring.