JPS6210529Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pressure seal gasket used in high-pressure pressure vessels such as valves and reactors.

The pressure seal structure (Bridgeman type seal structure) is widely used for sealing the lids of high-pressure vessels. FIG. 1 shows an example of this, in which an annular gasket 5 made of metal and having a wedge-shaped cross section is fitted near the end of the pressure vessel 1. The gasket 5 is held down by a cover 9 fixed to the end of the pressure vessel 1 with screws 2 so as not to come off. Furthermore, a ceiling plate 10 having a slope 11 is inserted inside the gasket 5. The ceiling plate 10 is suspended from the cover 9 by clamp bolts 12.

In the seal structure configured in this manner, when internal pressure P is applied, the ceiling plate 10 is pushed up.
As shown in FIG. 2, the angle of inclination of the slope 11 of the ceiling plate 10 with respect to the perpendicular is approximately 5 degrees larger than the angle of inclination θ of the inner circumferential surface 6 of the gasket 5. 7) is in contact with the inner circumferential surface 6. The tongue portion 7 expands in the outer radial direction due to the force F pushing up the ceiling plate 10, and the outer circumferential surface of the lower tongue end portion 8 closely contacts the inner circumferential surface 4 of the container to maintain a seal. The higher the internal pressure P is, the greater the force F' that pushes out the lower end 8 of the tongue becomes larger, and the sealing effect is further enhanced.

However, when assembling the pressure vessel 1, the initial tightening force is only applied by the clamp bolt 12, and the gasket 5 is often unable to obtain a sufficient spreading force F'. Therefore, when the internal pressure P is low or when the internal pressure P is low at the start of operation of the apparatus, fluid tends to leak from between the inner circumferential surface 4 of the container and the gasket 5. Further, even if the clamp bolt 12 is tightened to prevent leakage, sufficient gasket tightening force is often not obtained. In such a case, leakage marks may appear in the gasket 5 over time, and even if the internal pressure P increases and sufficient tightening force is generated, the leakage may not be stopped.

Although the inner circumferential surface 6 of the sublingual end portion 8 is in contact with the ceiling plate 10, a sufficient seal can be maintained between the two simply by the contact surface pressure of the ceiling plate 10 pressing against the inner circumferential surface 6. However, a large contact surface pressure cannot be obtained between the outer circumferential surface 6' of the sublingual end 8 and the inner circumferential surface 4 of the container as between the inner circumferential surface 6 of the sublingual end 8 and the ceiling plate 10. This is because part of the outward force that the lower tongue end 8 receives from the ceiling plate 10 is spent deforming the tongue 7, and the direction of this outward force does not match the direction of the contact surface pressure. (Therefore, the component of the force directed outward acts as the contact surface pressure.) For this reason, as described above, it is difficult to maintain a seal at low pressure using only the tightening force of the clamp bolt 12.

In order to obtain a sufficient sealing effect at low pressures, a gasket as shown in FIG. 3 has been proposed. In this gasket 13, the base 15 of the tongue 14
The thickness t of the tongue portion 14 is made small to facilitate deformation of the tongue portion 14. However, even if the base portion 15 is made thin in this manner, the large bending deformation of the gasket 13 cannot be obtained as in the case of a flat plate because the gasket 13 is annular. Therefore, the sealing effect cannot be increased to that extent at low pressure.

Further, as an auxiliary measure against leakage, it is conceivable to insert soft packing, an O-ring, etc. between the inner circumferential surface of the container 4 and the gasket 5 (see FIG. 2). However, handling these requires great care and also poses mechanical limitations.

This idea was made in order to solve the above-mentioned problems with conventional pressure seal gaskets.The idea was to create a pressure seal gasket that can obtain a sufficient sealing effect even when the internal pressure of the container is low. This is what we are trying to provide.

The pressure seal gasket of this invention has a groove provided along the circumference on the outer peripheral surface of the lower end of the tongue.

The area around the gasket groove is thin, and sudden changes in shape cause stress concentration. Therefore,
The area around the groove is easily deformed, and most of the deformation of the gasket due to the force from the ceiling board is taken care of by this area. That is, the deformation area of the gasket is limited to the area around the groove. For this reason, even if the gasket receives a relatively small force from the ceiling plate, the lower end of the tongue will be largely displaced in the outer radial direction.
The contact surface pressure with the inner peripheral surface of the container is large. As a result, a high sealing effect can be obtained between the inner peripheral surface of the container and the outer peripheral surface of the gasket.

Examples of this invention will be described below.

FIG. 4 shows an example of the gasket of this invention. The gasket 16 has a main body 17 and a tongue 18.
It's getting more familiar. The main body 17 constitutes the upper part of the gasket 16 and has a cylindrical shape. Tongue 18
has a wedge-shaped ring cross section,
It extends downward from the main body 17. The outer circumferential surface of the entire gasket 16 constructed in this manner is a cylindrical surface, and its outer diameter is large enough to fit snugly into the inner circumferential surface 4 of the container. The inner circumferential surface 19 of the tongue portion 18 is an inclined surface, and the inclination angle α with respect to the perpendicular line is within 30 degrees as in a normal gasket.
Incidentally, the inclination angle β of the slope 11 of the ceiling plate 10 in contact with the tongue inner circumferential surface 19 with respect to the perpendicular line is about 5 degrees larger than that of the tongue inner circumferential surface 19.

A groove 22 is provided along the circumference on the outer peripheral surface 21 of the tongue portion 18 near the lower end 20. The cross-sectional shape of the groove 22 is semicircular, and its radius R is the same as that of the gasket 1.
It depends on the size of 6, but about 0.5 to 5 mm is appropriate. If R is smaller than 0.5 mm, sealing performance will deteriorate. Further, even if R is made larger than 5 mm, the sealing performance does not particularly improve, and as R becomes larger, the distance l must be increased accordingly. lower end of tongue 20
The distance l from the groove 22 to the groove 22 is preferably as small as possible from the viewpoint of narrowing the deformation region and increasing the sealing effect as described above. However, if the distance l is too small, the thickness t' of the groove bottom becomes thin, and the gasket 16
There is a risk that the groove 22 will be crushed when more force is applied. That is, when the ceiling plate 10 is pushed up by the internal pressure P, the lower tongue end 23 (the part below the groove 22) that the ceiling plate 10 contacts also touches the ceiling plate 1.
0, and is pushed up by the frictional force between the groove and the bottom of the groove, producing a large compressive stress at the bottom of the groove. Therefore, if the thickness t' of the groove bottom is too thin, the groove bottom portion will be crushed. If the distance l is too large, the deformation will be unnecessarily wide for sealing. An appropriate distance l from these points is approximately (2 to 5)×Rmm.

The width b of the lower tongue end 20 is suitably about 0.5 to 2 mm in order to prevent damage when the gasket 16 is inserted into the container 1 and to facilitate deformation of the lower tongue end 23. Further, in order to prevent the above-mentioned damage and to improve conformity with the inner circumferential surface 4 of the container, the outer corner of the lower end 20 of the tongue may be rounded by 0.2 to 1 mm.

The gasket 16 configured as described above is the fifth
As shown in the figure, the inner corner of the lower end 20 of the tongue is in contact with the ceiling board 10. When the ceiling plate 10 receives an upward force from internal pressure or a clamp bolt, the gasket 16 deforms as shown by the chain line. Deformation is groove 22
The force is concentrated around the area around the sulcus, especially near the bottom of the groove, so even with a small force, the sublingual end 23 widely expands outward. Due to this deformation, the outer corner of the tongue lower end 23 comes into contact with the inner circumferential surface 4 of the container, and a seal is maintained.

In the conventional gasket 5, when a force is applied from the ceiling plate 10 as shown by the chain line in FIG. 6, the entire lower lingual end 8 deforms, and in order to maintain a seal, it must receive a stronger force from the ceiling plate 10. Therefore, sealing at low pressure is difficult as described above.

FIG. 7 shows another embodiment of this invention. The gasket 24 is shaped like a combination of two sets of tongues in a chevron shape. gasket 24
Grooves 25 are provided near the upper and lower ends of the housing. An intermediate piece 26 having a slope having the same inclination angle as the slope of the ceiling plate 10 is inserted between the gasket 24 and the cover 9.

The function of the gasket 24 in this embodiment is similar to that shown in FIG. 4, but since it is structured to seal at two locations, upper and lower, higher sealing performance can be obtained.

This invention is not limited to the above embodiment. For example, the cross-sectional shape of the groove may be a semi-ellipse or a U-shape instead of a semicircle. However, the groove bottom must have a smooth curved surface to avoid large stress concentration in the groove.

[Brief explanation of the drawing]

FIG. 1 is a sectional view explaining the entire pressure seal structure, FIG. 2 is a sectional view explaining the function of a conventional gasket, FIG. 3 is a sectional view showing another example of a conventional gasket, and FIG. The figure is a sectional view showing an example of the gasket of this invention, FIG. 5 is an enlarged sectional view of the tongue of the gasket shown in FIG. 4, and FIG. 6 is an enlarged sectional view of the tongue of the gasket shown in FIG. FIG. 7 is a sectional view showing another embodiment of the gasket of this invention. 1...Pressure vessel, 4...Inner peripheral surface of the container, 5, 1
3, 16, 24... Gasket, 6, 19... Tongue inner peripheral surface, 6', 21... Tongue outer peripheral surface, 7, 1
4, 18...Tongue, 9...Cover, 10...Ceiling plate, 11...Ceiling plate slope, 17...Gasket body, 20...Longer lower end, 22, 25...Groove, 23
...lower end of tongue.

Claims (1)

[Scope of utility model registration request] The circumferential surface 19 expands downward and has a tongue portion 18 with a wedge-shaped cross section, and the lower tongue end portion 23 contacts the slope 11 of the ceiling plate 10 and is expanded in the outer radial direction, so that the pressure vessel 1 In the annular solid gasket which is in close contact with the inner circumferential surface 4 of the tongue and self-seals fluid, a groove 22 having a semicircular cross-sectional shape is provided along the circumference on the outer circumferential surface 21 near the lower end 20 of the tongue. The radius of curvature R of the cross section of the groove 22 is from 0.5 to
5 mm, and the distance l from the lower end 20 of the tongue to the center of the radius of curvature R is (2-5)×R mm.