JPH0310437Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a self-pressurizing gasket used for sealing pressure-resistant stationary parts of various containers and equipment.

[Conventional technology]

Conventionally, as an example of this type of gasket, the 6th gasket
As shown in the figure, two annular lips 3 symmetrical to each other are located on one side (the inner diameter side in the figure) of an annular base 1 having a substantially rectangular cross section and having a required number of bolt insertion holes 2 in the circumferential direction. 4 are individually molded integrally. Each annular lip 3,4 defines a sealing surface 5,6 on the outside of its tip, both sealing surfaces 5,
6 is set larger than _{the width W 2 of} the annular base 1. This gasket is generally made of metal, and the sealing surfaces 5, 6 or the entire surface of the gasket is coated or plated with a soft sealing material (film) as required.

FIG. 7 shows an example of the use of the above gasket, in which the gasket is interposed between the upper and lower connecting members 7 and 8 when they are fastened with bolts 9, and the gasket is inserted between the upper and lower connecting members 7 and 8. When the bolt 9 is tightened until the screws ', 1' contact the connecting members 7, 8, both annular lips 3, 4 will close the gap between the sealing surfaces 5, 6.
It bends inward from W ₁ to W ₂ , and the reaction force at this time acts on the seal surfaces 5 and 6 as an initial load at the time of installation. When the fluid to be sealed is sent into the case constituted by the connecting members 7 and 8,
Fluid pressure acts on the back surfaces of the annular lips 3, 4 from the groove 10 between the two annular lips 3, 4, and the force generated by the pressure difference with the lip outer spaces 11, 12, which have a relatively low pressure, is applied to the sealing surface 5. , 6, and has a structure (self-pressure increasing type) in which the seal surface load increases as the pressure increases.

In this way, the gasket exhibits excellent sealing ability by effectively utilizing the working pressure of the fluid to be sealed, and furthermore, the outer part of this primary sealing part that presses the annular lips 3 and 4 against the connecting members 7 and 8 is By strongly tightening the bolt 9, a secondary seal is formed on the pressure contact surface between the annular base 1 and the connecting members 7 and 8. However, this secondary seal does not have a self-pressurizing function like the primary seal, so its sealing ability is inferior to that of the primary seal, so if there is only a small amount of leakage from the primary seal, it should not be used. Although it can be sealed, it cannot deal with cases where fluid pressure (case internal pressure) acts directly on the secondary seal portion.

[Problem that the invention attempts to solve]

In FIG. 7, which shows an example of the use of the gasket, if a leak occurs in one of the two primary seals arranged vertically in the figure, the leakage will pass through the seal and enter the lip outer space 11 or 12. The secondary seal part on the same side as the primary seal part (upper or lower in the figure) independently deals with the intruding fluid. However, as described above, the sealing ability of the secondary seal part is not so great, and for this reason, the secondary seal part often fails to seal completely and fluid leaks to the outside.

[Means for solving problems]

In view of the above points, the present invention aims to reduce leakage from the secondary seal portion without fundamentally changing the sealing ability of the secondary seal portion.
To achieve this purpose, the peripheral edge of the annular base, which is clamped between the connecting members to be connected to each other and forms the secondary sealing part, is pressed against the opposing surfaces of the connecting members to form the primary sealing part. Two annular lips are formed, and a communication hole is provided to communicate two outer spaces at both ends in the axial direction between the primary seal portion and the secondary seal portion.

[Effect]

In the gasket of the present invention having the above configuration, the two outer spaces 11 and 12 located at both ends in the axial direction are communicated with each other through the communication hole, so that when there is fluid passing through the primary seal part, the fluid can be removed. The pressure can be lowered by receiving the seal in both spaces 11 and 12 compared to the conventional case (accepting in only one of the spaces), and the opportunity for sealing at the secondary seal portion is correspondingly increased.

〔Example〕

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

In FIG. 1, reference numeral 21 indicates an annular base having a substantially rectangular cross section and having a required number of bolt insertion holes 22 in the circumferential direction. annular lip 23,
24 are integrally molded via a thin connecting portion 27, and a communicating hole 28 is formed through the connecting portion 27. Seal surfaces 25 and 26 are formed on the outside of the tips of the annular lips 23 and 24, and both seal surfaces 2
The interval W ₃ between 5 and 26 is set larger than the width W ₄ of the annular base 21 . The gasket is made of a metal material as in the conventional example, and the sealing surfaces 25, 26 or the entire surface are coated or plated with a soft sealing material (film) as required.

FIG. 2 shows the installation state of the gasket corresponding to FIG.
8 allows upper and lower outer spaces 11 and 12 in the figure to communicate with each other. If a leak occurs in the upper primary seal for some reason in this state, the fluid that has passed through the seal will enter the upper outer space 11 and pass through the communication hole 28 to the lower outer space. 12 is also accepted. Therefore, with this configuration, even if the same amount of leakage occurs as compared to the conventional example, since the receiving volume is approximately doubled, the pressure of the leaked fluid can be approximately halved, and the sealing capacity is the same as that of the conventional example. The secondary seal portion can increase the chances of sealing the fluid. The location where the communication holes 28 are formed and the number thereof are not particularly limited. It should be noted that it has become clear from the previous explanation that this configuration does not assume a case where one of the primary seals is completely destroyed.

Next, the bifurcated annular lips 23 and 24 and the thin connecting portion 27 added to the above structure will be explained.

In FIG. 7, which shows an example of the use of the prior art, if the connecting members 7, 8 themselves are deformed due to an increase in pressure or generation of high heat, a situation arises in which the annular lips 3, 4 are unable to follow the deformation. is possible.
That is, as shown in FIG. 8, when one of the connecting members 7 exhibiting a lid shape is deformed greatly, the upper annular lip 3 is structured to follow this by itself, so it quickly reaches the limit of its following, and the sealing surface 5 and A gap is formed on the lower surface of the connecting member 7, and a large amount of fluid leaks from this gap.

The structure in which the bifurcated annular lips 23 and 24 are connected to the annular base 21 via the thin connecting portion 27 is intended to enhance the sealing ability against such leakage. That is, from the state shown in FIG. 2, the pressure of the fluid to be sealed that has been sent into the case increases, and as shown in FIG. 3, the upper connecting member 7
When deformed, the bifurcated annular lip 23, 2 connected to the annular base 21 via the thin connection part 27
4, including the connecting portion 27, performs a follow-up operation. That is, the upper annular lip 23 follows the deformation of the connecting member 7 and actually moves by the same amount, and the connecting portion 27 faces upward in an angle corresponding to 1/2 of the amount of deformation (∠θ). Although the lower annular lip 24 appears to be stationary, the amount of deflection is relatively reduced as the connecting portion 27 changes direction. In this way, the gasket follows the deformation of the connecting member 7 by changing the direction of the bifurcated annular lips 23, 24, so that the amount of deflection of both the annular lips 23, 24 is always kept almost equal. It is possible to completely follow the connecting member 7 with half the displacement of the annular lip 23 compared to the conventional example. The connecting portion 27 connecting the annular lips 23, 24 and the annular base 21 can be modified in various ways, such as by forming it into a bellows shape. In this way, even if deformation to the extent that the sealing function is lost occurs in the prior art, the configuration allows the annular lip to follow the deformation, and the sealing performance can be improved accordingly. In addition, the same degree of flexure is always applied to each of the two bifurcated annular lips to maintain the same sealing load on both sides, and the load is not unevenly distributed unlike the conventional technology in which the following action is left to one lip. Problems such as one lip becoming fatigued first can be resolved.

Next, an example of a sealing mechanism using the gasket shown in FIG. 1 will be explained according to FIG. 4.
In comparison with FIG. 2, this device has a leakage fluid recovery hole 29 in the connecting member 8 on the upper and lower sides of the figure that also communicates with the outer space 12 on the lower side. The recovery pipe 30 can be opened from the recovery hole 29 without leaking from the next seal.
It is characterized by being configured so that it can be recovered to a tank or other processing system 31 via the sealing system, and is particularly suitable for use when the fluid to be sealed is toxic or potentially explosive. In addition to this configuration, it is also possible to control the flow rate of the main high-pressure pipe 32 that feeds the fluid to be sealed into the case based on the pressure and flow rate of the leaked fluid flowing through the recovery pipe 30. The branched pipe 33 is connected to a control valve 34 provided midway through the high-pressure pipe 32 to control the flow rate of the high-pressure pipe 32. 35 is a monitor. Further, a sensor 36 can also be used for this control as shown in FIG.

[Effect of idea]

As explained above, the self-pressurizing gasket of the present invention is clamped between connecting members that are connected to each other and is pressed against the opposing surfaces of the connecting members on the periphery of the annular base constituting the secondary seal. Two annular lips constituting a primary seal part are formed, and a communication hole is provided for mutually communicating two outer spaces at both ends in the axial direction formed between the primary seal part and the secondary seal part. As a result, fluid leaking from the primary seal can be effectively prevented by the secondary seal, reducing the risk of external leakage compared to the prior art.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of a gasket according to an embodiment of the present invention, Figs. 2 and 3 are sectional views showing how the gasket is used, and Figs. 4 and 5 are sectional views showing how the gasket is used. FIG. 6 is a cross-sectional view of a main part of a conventional gasket, and FIGS. 7 and 8 are cross-sectional views showing how the same gasket is used. 1, 21... Annular base, 2, 22... Bolt insertion hole, 3, 4, 23, 24... Annular lip, 5,
6, 25, 26... Seal surface, 7, 8... Connecting member, 9... Bolt, 10... Groove, 11, 12...
...Outside space, 27...Connecting portion, 28...Communication hole,
29... Leakage fluid recovery hole, 30... Recovery piping, 3
1... Processing system, 32... Main high pressure piping, 33...
... Branch pipe, 34 ... Control valve, 35 ... Monitor,
36...Sensor.

Claims (1)

[Scope of utility model registration request] 2, which is clamped between connecting members that are connected to each other;
Two annular lips are formed on the periphery of the annular base constituting the secondary seal portion, and are pressed against the opposing surfaces of the connecting members to constitute the primary seal portion;
A self-pressurizing gasket characterized in that a communication hole is provided that communicates two outer spaces at both axial ends formed between a secondary seal part and a secondary seal part.