JPH0374692A - Seal mechanism for valve pipe - Google Patents

Abstract

PURPOSE:To perform direct adhesion of a seal surface by a method wherein a seal mechanism comprises an annualar gasket space formed between the annular coupling surfaces of two members and an annular gasket, the gasket space is formed in the shape of a wedge in cross section, and the gasket is formed in a shape in which the side of a wedge shape is swollen. CONSTITUTION:A valve body 10 is disassembled into a body part 11 and a flange part 12, and the flange part 12 is securely fastened against the body part 11 through a bolt 13 and a nut 14. An annular coupling surface 16 of the flange part 12 is adhered to an annular coupling surface 15 of the body part 11, a wedge-shaped gasket space 17 in a right angles triangle in cross section is formed between the annular coupling surfaces, and a gasket 18 is arranged. The gasket space 17 is formed in the shape of a wedge in cross section when the annular coupling surface 16 is adhered thereto. The gasket 18 is formed in a shape wherein the side of a wedge shape is swollen, and an expandable 19 is mounted externally of an outer peripheral surface. As a result, the sizes in a fastening direction of the two members are always kept at a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a sealing mechanism provided on an annular joint surface between members such as valves and pipes each having a flow path inside.

[Conventional Technique #t] When a two-part valve body is assembled or two flange pipes are connected, a sealing mechanism is provided on the annular joint surface to prevent fluid from leaking through the internal flow path. .

The conventional sealing mechanism, as shown in FIGS. 8 and 9,
The two members 11.12 are composed of an annular seat 41.42 provided separately from the opposing coupling surfaces 15.18, and an annular gasket 40 disposed on the annular seat, and the gasket 40 is connected to the bolt! 3. Natsuto! 4 was a mechanism that was compressed by force and tightly sealed against the annular seat surface.

[Problems to be Solved by the Invention] In the conventional sealing mechanism, even when the bolts 13 and nuts 14 are tightened during assembly, the connecting surfaces 15 and IBs of the two members 11 and 12 do not come into close contact with each other, so it is difficult to tighten the assembled members. The related dimension in the direction of attachment is determined by the amount of compression of the gasket 40.In the case of a ball valve, the force acts directly on the ball, but the force of tightening varies from person to person. , bolt 13, and nut 14, so the torque required to open and close the valve cannot be constant.Also, if a compressive load is applied when piping is connected to a ball valve, that load will be transferred directly to the seat. Since it is applied to the ball, the valve opening/closing torque increases, and in the case of an automatic valve, it may not be possible to open/close it with the output of the drive unit.

The present invention has been made to solve these problems, and its purpose is to provide a sealing mechanism that can bring the annular joint surfaces of two joining members into direct contact with each other.

[Means for Solving the Problems] In order to achieve the above object, the means adopted by the present invention is to bring the annular coupling surfaces surrounding the flow path of the two members into close contact with each other, and insert an annular gasket having a wedge-shaped cross section between them. A space is formed, a wedge-shaped gasket with a convex center is attached to the gasket space, and a telescopic ring is removed from the outer circumferential surface of the gasket.

C action] When two members are tightened to bring their annular joint surfaces into close contact,
The swollen portion of the gasket with a wedge-shaped cross section that is fitted into the gasket space with a wedge-shaped cross section is deformed to closely contact and seal the two wedge-shaped surfaces of the gasket space. In addition, the gasket is tightened against the telescoping ring, creating the necessary stresses for the seal.

[Example] A sealing mechanism of the present invention will be described based on an example shown in the drawings.

As shown in FIG. 1, the valve main body 10 is disassembled into a main body 11 and a flange part 12, and the flange part 12 is tightened to the main body part 11 through a bolt 13 and a nut 14. The annular coupling surface 18 of the flange portion 12 is in close contact with the annular coupling surface 15 of the flange portion 12, and a wedge-shaped gasket space 17 having a right triangular cross section is formed between the two.

A gasket 18 is arranged in the gasket space 17.

As shown in Figure 2, an annular synthetic resin gasket 1
8 has a right triangular wedge-shaped cross section with the oblique side bulging outward, and a metal telescopic ring 18 is attached to the outer periphery. An annular coupling surface 15 is formed between the main body portion 11 and the flange portion 12 of the valve body.
An annular groove 21 having a wider width than the telescopic ring 18 is provided on the inner circumferential surface 22 of the inner cylinder surrounding the 0-body connecting surface 15 where the rings 18 are respectively provided. The flange portion coupling surface 1B is surrounded by a conical surface 23, and the conical surface is fitted on the inner cylinder outer circumferential surface 24. bonding surface l
The axial distance from B to the inner cylinder outer circumferential surface 24 is equal to the axial width of the gasket 18.
When assembling the main body part joint [15] and the flange joint surface 1B, as shown in FIG. The protrusion 4125 of the annular slope contacts the flange conical surface 23 without being in close contact and without compressing the gasket 18.

When the nut shown in Fig. 1 is tightened, as shown in Fig. 3, the connecting surface 15 of the main body SLL and the connecting surface 18 of the flange portion 12 come into close contact, the gasket 18 is compressed, and its annular slope is ranked 7. The seventh annular end surface is connected to the conical surface 23 of the main body portion 15.
closely adhere to. At this time, the gasket 18 expands the telescopic ring 19, and the telescopic ring 19 fits into the annular groove 21 in the gasket space 17. Since the gasket 18 is tightened by the telescopic ring 19 and tightly seals the main body part coupling surface 15 and the flange part conical surface 23, there is no risk of internal fluid leaking.When the valve main body IO is assembled, the main body part 11 and Since the flange portions 12 are in direct contact with each other, the relative dimensions in the joining direction are always constant.

As the internal fluid becomes hot or cold, the gasket 18 expands or contracts, and the telescoping ring 18 also expands and contracts to provide the necessary internal stress to the seal, so that the first
Figure Natsuto! There is no need to tighten the ring 4. If necessary, the telescopic ring 18 may be made of a shape memory alloy to strengthen the tightening force at high temperatures.

As shown in FIG. 4 or 5, the sealing mechanism of the present invention can also be applied to a flange pipe.

The joining surface 15 of one flange pipe 31 is flat, and the joining surface 1B of the other flange pipe 32 has a gasket base l7.
form. The inner circumferential surface 38 of the gasket space 17 is shaped like a cone that becomes narrower on the end surface side. The annular gasket 18 has the same shape as in the previous embodiment, and the convex portion 25 contacts the conical inner circumference 38 as shown in FIG. 4 before the bolt 13 and nut 14 are tightened. When the bolts 13 and nuts 14 are tightened, both flange pipes 3 are tightened as shown in FIG.
The joining surfaces 15 and 16 of 1.32 come into close contact with each other, and a right triangular wedge-shaped gasket space 17 is formed, and the gasket 18 is compressed and the annular slope forms the flange pipe 3.
The conical inner peripheral surface 38 of No. 2 and the joint surface 15 of the flange pipe 31 are tightly sealed. At this time, a void remains outside the telescopic ring 13. Since the telescoping ring 18 is expanded by the gasket 18, the gasket 18 is tightened and the internal stress necessary for sealing is applied to the gasket 1B.

As shown in FIGS. 6 and 7, both 7-lunge pipes 31
．． A gasket 18 having an isosceles triangular cross section and forming a symmetrical gasket space 17' may be attached to the connecting surface 15.18 of the port 13.32, as shown in FIG. Before tightening the bolt 14, the convex portion 25.2B of the symmetrical annular slope of the gasket 18 was in contact with both conical inner circumferential surfaces 38.38, and as shown in FIG. When tightened, the connecting surfaces 15 and 18 will come into close contact with each other and the 2
A wedge-shaped gasket space 17 having an equilateral triangular shape is formed, and the gasket/1.18 is compressed to tightly seal the two annular slopes to the conical inner circumferential surfaces 3B and 38 of both flange pipes. At this time, the two telescoping rings 18 tighten the gasket 18 to provide the necessary internal stress for the seal.

[Effects of the Invention] As mentioned above, the sealing mechanism of the present invention is different from the conventional sealing mechanism in which the joining surfaces of two members to be joined cannot be brought into direct contact with each other, and the sealing mechanism of the present invention is capable of bringing the joining surfaces into direct contact with each other. Because of this, the relative dimension in the direction of tightening of the two joined members is always constant. Therefore, when the two parts are the valve body, the required rotational torque of the stem can be maintained constant without being affected by force or piping when tightening bolts and nuts, especially in the case of automatic valves. This can prevent accidents in which the opening and closing become impossible due to insufficient driving force during use. Furthermore, in the case of a ball valve, not only the force applied to the gasket but also the force applied to the ball and seat are constant, eliminating variations from valve to valve. Since the expansion and contraction of the gasket due to the temperature of the fluid is absorbed by the expansion ring, there is no need for a term line due to temperature changes. When the cross section of the gasket space and the gasket are shaped into a right triangle, processing is easier and manufacturing costs are lower than with the conventional annular bearing surface on which the gasket is attached.

Show.

FIGS. 6 and 7 are views corresponding to FIGS. 4 and 5 of another embodiment.

8 and 9 are cross-sectional views of a ball valve and a flange pipe equipped with a conventional sealing mechanism.

In the figure, numeral 11 is the main body IB (one of the two members)
, 12 is a flange part (the other of the two members), 15,
18 is an annular coupling surface, 17 is a gasket space, 18 is a gasket, and 18 is a telescopic ring.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a ball valve equipped with a sealing mechanism according to an embodiment of the present invention, and FIGS. 2 and 3 are enlarged sectional views of main parts of FIG.
Figure 2 shows the state before tightening of bolts and nuts, and Figure 3 shows the state after tightening.

Claims (1)

[Claims] 1) An annular gasket space (17) formed between the annular coupling surfaces (15, 18) surrounding the flow path of the two members (11, 12), and an annular gasket made of synthetic resin attached to the gasket space. In the sealing mechanism comprising a gasket (18), the gasket space has a wedge-shaped cross section when the annular coupling surfaces are brought into close contact with each other,
The sealing mechanism for a valve pipe is characterized in that the cross section of the gasket has a shape in which the wedge-shaped side of the gasket space is bulged, and a telescopic ring (19) is removed from the outer peripheral surface of the gasket.