JPS62233584A - Bellows valve - Google Patents

Abstract

PURPOSE:To aim at the promotion of long service life in a bellows, by forming a sealing chamber between a cylindrical barrel part of a valve plug and a guide ring, while interconnecting this sealing chamber to an inner chamber of the sealing bellows, and charging an incompressible fluid into both these chambers before sealing. CONSTITUTION:A sealing chamber 11, where the content volume of a valve is increased or decreased at the time of its actuation, is formed between a cylindrical barrel part 7 of a valve plug 5 and a guide ring 6, and this sealing chamber 11 is interconnected to a bellows inner chamber 12 via an interconnecting passage, while an incompressible fluid is charged into both these chambers 11 and 12 and sealed up. With this constitution, the volume increment and decrement values between the bellows inner chamber 12 and the sealing chamber 11 are accorded with each other, and since internal pressure top be added to a bellows 10 is maintainable to the specified value, partial plastic deformation or the like in this bellows 10 is prevented, thus improvement in pressure resistance and the promotion of long service life for the bellows 10 can be attained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is used for fluid control in the petroleum industry, chemical industry, etc., and is configured so that leakage of fluid from a moving part of a valve to the outside can be sealed by a bellows. Regarding bellows valves.

[Conventional technology]

This type of bellows valve completely prevents leakage of fluid from the part that supports the valve's moving parts to the outside of the valve, when the fluid to be controlled is toxic, volatile, flammable, etc., or is expensive. It is effective when adopted when it is necessary to prevent such problems, and its usefulness is great.

That is, this type of conventional bellows valve includes a valve plug having a fluid control section that opens and closes a fluid passage formed within the valve body by being externally operated by a valve shaft disposed through the upper cover, and the valve plug. The valve body includes a guide ring provided on the valve body side so as to slidably support the cylindrical body. In order to prevent the control fluid flowing in the fluid passage from leaking to the outside of the cell from between the cylindrical body of the valve plug as the valve movable part and the guide ring that slidably supports the body. A molded bellows for sealing is fitted onto the cylindrical body of the valve plug, and its movable end is welded to the tip of the valve plug, and its fixed end is welded to the end of the guide ring. , the bellows was configured to seal the control fluid acting at a predetermined pressure from the outside.

[Problem that the invention seeks to solve]

However, as mentioned above, in the case of molded bellows that are fixed to the valve plug and guide ring sides by welding, etc., the bellows It was inevitable that the respective bulges would vary in strength.

According to a bellows that has such variations in strength, when the bellows expands and contracts during valve operation, the weak bulging portion displaces more than the other bulging portions, and the degree of deformation increases. It becomes large, and if external pressure is applied in this state, the above-mentioned part will buckle and collapse.

The final one caused problems such as damage and shortening the life of the bellows.

In particular, such sealing bellows are generally made of thin sheet material because of the required flexibility, and as a result, processes that use high-pressure control fluids require This poses an application problem in that a bellows valve cannot be used, and it is desired to take some measures to improve the pressure resistance of the bellows as described above and to extend the life of the bellows.

[Means for solving problems]

In order to meet such demands, the bellows valve according to the present invention has a valve actuation mechanism between the cylindrical body of the externally operated valve plug and the guide ring on the valve body side that slidably supports the cylindrical body of the valve plug. It forms a sealed chamber whose internal volume increases and decreases over time, and communicates this sealed chamber with the inner chamber of a sealing bellows interposed between the valve plug and the guide ring. It is designed to be filled and encapsulated.

[Effect]

According to the present invention, when the valve is operated, the volume increase/decrease of the bellows inner chamber and the containment chamber are made to match each other, thereby maintaining the internal pressure applied to the bellows at a predetermined value, and thereby causing partial plastic deformation of the bellows. 11-, etc., and can achieve a longer service life.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 1 shows an embodiment of a bellows valve according to the present invention. In the same figure, first, the general structure of the bellows valve, which is indicated by reference numeral 1, will be briefly described. This bellows valve 1 has two ends. A valve body 2 has a flange for connecting piping to the valve body 2, an upper cover 3 that is fixedly attached to the upper part of the valve body 2 with bolts and closes the upper opening of the valve body 2, and a valve body 2 that is disposed through the upper cover 3 and is not shown in the drawings. a valve plug 5 that is provided at the inner end of the valve shaft 4 that is externally operated by a drive device, faces into the fluid passage 2a in the valve body 2, and is operated from the outside;
A guide ring 6 is provided between the opening of the valve body 2 and the upper cover 3 so as to slidably support the valve plug 5.
It is equipped with Note that 2b in FIG. 1 is a communication hole provided in a partition wall 2C that defines a fluid passage into an inflow side and an outflow side in the valve body 2, and whose opening and closing are controlled by a fluid control section at the tip of the valve plug 5. Further, reference numeral 7 in the figure represents a cylindrical body portion that constitutes the valve plug 5 and is slidably supported within the center hole 6a of the guide ring 6. Furthermore, 5a in the figure is a seat portion made of synthetic resin or the like that sits on a planar valve seat provided at the upper opening edge of the flow hole 2b, and a tightening screw 5b.
The attachment is fixed to the inner end surface of the valve plug 5.

The control fluid flowing in the fluid passage 2a is prevented from leaking to the outside of the valve from between the cylindrical body 7 of the valve plug 5 as a valve movable part and the guide ring 6 that slidably supports it. The molded bellows 10 is formed into a substantially cylindrical shape from a thin plate material having the required flexibility, and is used as a seal for sealing the valve plug 5.
The movable end is welded and fixed to the tip side of the valve plug 5 and the fixed end to the inner end side of the guide ring 6, so that a predetermined pressure is applied from the outside of the bellows 10. It was designed to seal the control wave body.

Now, according to the present invention, in the bellows valve 1 having the above-described configuration, the valve plug 5 is provided between the cylindrical body 7 of the valve plug 5 and the guide ring 6 on the valve body 2 side that slidably supports the valve plug 5. Forms a filling chamber 11 whose internal volume is increased or decreased when the valve is operated by the downward movement of 5.
1 is communicated with the bellows inner chamber 12 via a communication passage 13, and both chambers 11 and 12 are filled with an incompressible fluid 14.

Here, according to an unimplemented example, an annular groove 6b is formed in the central hole 6a of the guide ring 6 on the valve shaft 4 side, and this annular groove 6b and the outer circumference of the cylindrical body 7 are connected to each other, and furthermore, the cylindrical shape A space formed by a cover ring 15 as a flange-like member provided at the end of the body 7 on the valve shaft 4 side is used as the sealing chamber 11. Note that 15a and 15b are O-rings for sealing the joint portion formed by the cover ring 15.

According to the above-mentioned configuration, when the valve is operated, the volume increase/decrease of the sealing chamber 11 and the bellows inner chamber 12 are made to match each other, thereby maintaining the internal pressure applied to the bellows 10 at a predetermined value, and thereby This prevents partial plastic deformation of the bellows 10, improves the pressure resistance of the bellows 10, and extends its service life.

Here, by having the above-mentioned configuration, the bellows 10, the sealing chamber 11, and the valve plug are arranged so that the volume changes of the filling chamber 11 and the bellows inner chamber 12 are approximately the same when the valve is operated. It is only necessary to set the dimensional relationship of each part, such as 5, etc., as appropriate.

That is, the dimensional relationships set as described above will be briefly explained. First, let the inner diameter of the annular groove 6b of the guide ring 6 be D, the effective diameter of the bellows 10 be d, the outer diameter P of the cylindrical body 7 of the valve plug 5, the valve stroke be 12 volume changes A and B
Then, A=π/4 fist (D2-p2)・Sentence B=π/4- (d!1-P2) 0 sentences.

In this case, if D=d, when the valve operates from the open state to the closed state, the volume reduction of the sealing chamber 11 becomes the volume increase of the bellows inner chamber 12, and the valve plug 5
Normal operation is obtained, and when the valve 1 operates from closing to opening, the above-mentioned increase/decrease relationship is simply reversed, and the sealed liquid (incompressible fluid 14) is filled throughout the entire opening. . Therefore, the filled liquid (14) holds each bulge of the bellows 10 from the inside, and the conventional problem of stress concentrating on the bulge, which has a strength problem and buckling, is eliminated, and the bellows 10
It has the advantage that it can achieve a long life of 0 and can be used even under high pressure.

Here, the incompressible fluid 14 sealed in the sealed chamber 11 and the bellows inner chamber 12 described above may generally be water, but it is more effective to use, for example, oil with high viscosity. Moreover, when using in a low temperature state, it is preferable to use liquid helium or the like.

FIG. 2 shows another embodiment of the present invention. In this embodiment, instead of the cover ring 15 that closes the valve shaft 4 side of the sealing chamber 11, a flange portion 20 is provided on the valve plug 5 side.
are integrally formed, and this flange portion 20 closes the enclosure chamber 11.
The structure is such that it seals. In this case, the incompressible fluid 14 is sealed in the fluid control section (
It is preferable to use the screw hole 21 of the tightening screw 5b on the side 5a) as an introduction passage.

In addition, FIG. 3 shows the inner hole portion of the guide ring 6 (center hole 6a).
) are formed with the same diameter, and FIG. 4 shows an embodiment in which the outer diameter of the containment chamber 11 does not match the effective diameter d of the bellows.

In this case, if the volume changes of the inclusion chamber 11 and the bellows inner chamber 12 are C and D, and the outer diameter of the cylindrical body 7 forming the inclusion chamber 11 is p, then C=π/4 (D2-p2
)e sentence=π/4・(d!l psi)Φ sentence. In both of these equations, it is preferable to appropriately select dimensions I), p; d, and P such that C=D, that is, the cross-sectional areas are equal.

Note that the present invention is not limited to the structure of the embodiments described above, and the shape and structure of each part may be modified or changed as appropriate.
Various modifications are possible. For example, in the above-mentioned embodiment, the bellows valve l according to the present invention was explained as a single-seat valve type, but it can also be effectively applied to a valve having an angle type valve body, and the tip shape of the valve plug 5 It will be readily understood that it may have various type characteristics.

〔Effect of the invention〕

As explained above, according to the bellows valve according to the present invention, there is a seal whose internal volume increases or decreases when the valve is operated, between the cylindrical body of the valve plug and the guide ring that slidably supports it. A chamber is formed, and this sealed chamber is communicated with the inner chamber of the sealing bellows interposed between the valve plug and the guide ring, and both chambers are filled and sealed with an incompressible fluid. Despite its inexpensive configuration, when the valve is actuated, the volume increase and decrease of the bellows internal chamber and the containment chamber are made to match each other, thereby maintaining the internal pressure applied to the bellows at a predetermined value, and thereby partially reducing the volume of the bellows. It has various excellent effects such as preventing plastic deformation, improving the pressure resistance of the bellows, and extending its life.

[Brief explanation of drawings]

FIG. 1 is an overall schematic sectional view showing one embodiment of a bellows valve according to the present invention, and FIGS. 2 to 4 are sectional views of essential parts showing other embodiments of the present invention. 1 fist... bellows valve, 2... valve body, 2a...
・Fluid passage, 3-fist fight ・Top lid, 4.・valve stem, 5...
...Valve plug, 5a... Seat part (fluid control part), 6... Guide ring, 6a... Center hole, 6
b... annular groove, 7... cylindrical body, 10...
-Bellows, 11--Enclosed chamber, 12--Fist/bellows inner chamber, 13-Fist/Series passage, 14--Incompressible fluid as enclosed liquid, 15--Covering.

Claims (1)

[Claims] A movable end is fitted to a cylindrical body of a valve plug that is externally operated by a valve shaft, and a movable end is fixed to a part of the cylindrical body, and a fixed end is provided on the valve body side that slidably supports the cylindrical body. In a bellows valve comprising a sealing bellows fixed to a guide ring, a sealed chamber whose internal volume increases or decreases when the valve is actuated is formed between the cylindrical body of the valve plug and the guide ring, A bellows valve characterized in that the sealed chamber is communicated with the bellows inner chamber, and both chambers are filled and sealed with an incompressible fluid.