JP4243120B2 - High pressure gas sealed structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing structure for sealing high-pressure gas, and particularly to a sealing structure for sealing highly permeable hydrogen gas or helium gas.
[0002]
[Prior art]
Few known sealing seals are suitable for sealing a high-pressure gas with a significant pressure fluctuation as a fluid and have a simple structure. For high-pressure gas with no pressure fluctuation (constant pressure), rubber O-rings provide excellent sealing (sealability), but under operating conditions that cause frequent pressure fluctuations between low pressure and high pressure (under the environment In this case, this O-ring cannot be used.
[0003]
[Problems to be solved by the invention]
The reason why the pressure fluctuation cannot be used under the use conditions is that blisters are generated in the rubber O-ring.
[0004]
That is, gas such as hydrogen gas or helium gas (highly permeable) as a sealed fluid penetrates inside the rubber O-ring, and is held inside the O-ring as a high-pressure gas (in a compressed state) inside the O-ring at high pressure. Has been. When the high-pressure environment is released (suddenly low pressure), the high-pressure gas held inside the O-ring is about to be released while expanding rapidly, so a phenomenon that microbubbles appear inside the O-ring. Blister is generated and sealability (sealability) is lost.
[0005]
Therefore, an object of the present invention is to provide a sealing structure that is sufficiently applicable and simple and compact even in an environment in which a pressure fluctuation between the low pressure and the high pressure is remarkably generated. .
In particular, a blister is prevented from being generated by a simple structure, and a sealing structure having excellent durability (long life) is provided.
[0006]
[Means for Solving the Problems]
According to the present invention, a secondary seal with a sealing lip made of resin is disposed on the high pressure side of an O-ring as a main seal for high-pressure gas sealing, and the opening groove of the secondary seal is provided with the O-ring. Arranged to face. The high pressure gas is high pressure hydrogen gas.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
[0008]
FIGS. 1 to 3 show a first embodiment of the present invention, and are sectional views of a principal part of a sealing structure for sealing a gap 13 between a first member 11 and a second member 12.
[0009]
One of the first member 11 and the second member 12 is, for example, a valve body, a joint body, a casing, and the like, and the other is, for example, a spool (valve rod), a joint insertion cylinder, a pipe end, or the like. The fixing part sealing structure in which the second member 12 is inserted into the hole of the first member 11 or the fixing part sealing structure in which the first member 11 is inserted into the hole of the second member 12. Alternatively, the second member 12 is inserted into the hole of the first member 11, or the first member 11 is inserted into the hole of the second member 12, and the axial direction is relatively relative to the vertical direction in the figure. ── shows the sliding part sealing structure that reciprocates or rotates relatively around the axis.
[0010]
In any case, the gap 13 is generally cylindrical. On the other hand, one of the first member 11 and the second member 12 is a casing flat part, a joint flange flat part, etc., and the other is a lid member flat part, a joint flange flat part, etc., and does not move relatively. A fixed part sealing structure may be used. In this case, the gap 13 has a planar shape.
[0011]
FIG. 1 is a cross-sectional view of a main part that also serves as a schematic explanation of the arrangement, FIG. 2 shows a state in which high pressure P is applied (high pressure action state), and FIG. 3 rapidly decreases the high pressure P after FIG. Indicates (decompressed) state ─── decompressed state ───.
[0012]
Reference numeral 1 denotes a rubber O-ring as a main seal for high-pressure gas sealing. In the drawing, the upper side is a high pressure side H, and a secondary seal 2 with resin seal lips 3, 3 is disposed (attached) on the high pressure side H with respect to the O-ring 1.
[0013]
In addition, the secondary seal 2 is disposed so that the opening groove 4 formed by the pair of seal lips 3 and 3 faces the O-ring on the low pressure side L.
In the illustrated example, two concave grooves 6 and 7 are formed in the second member 12, and an O-ring 1 and a secondary seal 2 are attached to each.
[0014]
The sub-seal 2 has a U-shaped cross-sectional shape in FIGS. 1 to 3 and uses a fluorine-based resin such as PTFE, nylon, or the like. As shown in FIG. 2 from the state of FIG. 1, if the high pressure P of the high pressure gas acts from the high pressure side H, the seal lip 3 of the sub seal 2 in which the opening concave groove 4 faces the low pressure side L becomes narrow. 2 is deformed in the direction, and instantaneously (if extremely illustrated), the gap G in FIG. 2 is generated, and high pressure P is passed through the O-ring (main seal) 1, and the O-ring (main seal) 1 Seal. FIG. 2 shows a state where the O-ring 1 is pressed (elastically compressed) in the concave groove 6 toward the low-pressure side and has a sealing action.
[0015]
After that, as shown in FIG. 3, when the pressure on the high-pressure side H suddenly decreases, the opening groove 4 of the secondary seal 2 faces the O-ring 1 side and tries to escape from the O-ring 1 side to the high-pressure side H. The high pressure gas is immediately sealed (sealed) by the seal lips 3 and 3, and as shown by an arrow P in FIG. 3, the contact portion 8 of the O-ring 1 and the seal lip 3 of the sub seal 2 are in contact with each other. The range Z up to the portion 3a is maintained at a high pressure. That is, even if the high pressure side H is suddenly reduced, in this range Z, the pressure remains high for a while, and the pressure in this range Z is gradually (slowly) reduced. As a result, it is possible to effectively prevent the high-pressure gas that has penetrated into the O-ring 1 under high pressure from suddenly expanding and releasing to generate blisters. In this way, the self-sealing property of the sub-seal 2 is utilized, and when the sub-seal 2 is suddenly depressurized from the high pressure P, the pressure acting on the O-ring 1 in a high pressure state is gradually increased ( It can be said that it has a function as a pressure reduction rate relaxation seal for reducing pressure slowly. And as said high pressure gas, when it applies to high pressure hydrogen gas, the sealing effect of the sealing structure which concerns on this invention is remarkable. That is, hydrogen gas has recently increased its use at high pressure and has a property of being easy to permeate due to its small molecular particle size. However, the sealed structure according to the present invention is resistant to such high-pressure hydrogen gas. Significant sealing performance can be demonstrated.
[0016]
Next, FIG. 4 shows a second embodiment of the present invention. FIG. 4 shows that a backup ring 14 for preventing protrusion at high pressure may be added to the O-ring 1 as the main seal. Furthermore, it is also preferable to provide another resin seal 15 on the high pressure side H than the above-described sub seal 2. The resin seal 15 is disposed so that the seal lips 16 and 16 face the high-pressure side H. When the high pressure P is applied, the resin seal 15 is sealed as a self-sealing seal, and the pressure is directly applied to the O-ring 1. It plays the role of a buffer that is not subject to sudden increase fluctuations. Other than that, the same reference numerals as those in FIG.
[0017]
Next, FIG. 5 is a cross-sectional view showing a modification of the sub seal 2, and an annular coil spring 17 may be provided as shown in FIG. In particular, the coil spring 17 is preferably added to the seal lip 3 side that contacts the first member 11. Further, as shown in FIG. 5 (B), the secondary seal 2 is formed into an elongated U-shape having a large length from the front end portion of the seal lip 3 to the bottom surface 18 or an angular C shape as shown in FIG. 5 (C). The shape of the letter --------------------- or the rounded C-shape shown in Fig. 5 (D) is also free. Furthermore, it is also preferable to use a V shape as shown in FIG. 5 (E), or to install a metal (plate) spring having a U-shaped cross section in the opening groove 4 as shown in FIG. 5 (F).
[0018]
The high-pressure gas sealing structure according to the present invention is configured as described above, and can be applied not only for fixing (stationary) but also for sliding or rotating in the axial direction, and only for sealing cylindrical surfaces. In addition, it can be applied to flat sealing.
[0019]
【The invention's effect】
The present invention has the following remarkable effects by the above-described configuration.
[0020]
In other words, since the opening groove 4 faces the O-ring 1 as the main seal, the high pressure P once applied to the O-ring 1 is sealed for a predetermined time even if the pressure on the high-pressure side H decreases rapidly. It is possible to prevent the blister from being generated in the O-ring 1 by gradually reducing the pressure. Therefore, the life of the O-ring 1 as the main seal is long and the sealing performance (sealing performance) can be maintained over a long period.
[0021]
In addition, the addition of the sub seal 2 and its concave groove 7 (seal groove) makes this sealing structure easy to manufacture, compact, and advantageous in terms of cost.
[0022]
And (according to claim 2), hydrogen gas having a property of easily permeating (small molecular particle size) is effectively sealed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing an embodiment of the present invention.
FIG. 2 is an explanatory cross-sectional view of a main part showing a pressure state where a high pressure is applied.
FIG. 3 is an explanatory cross-sectional view of a main part showing a state where the high pressure suddenly disappears thereafter.
FIG. 4 is a cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 5 is a cross-sectional view showing various other embodiments of the sub-seal.
[Explanation of symbols]
1 O-ring 2 Sub seal 3 Seal lip 4 Open groove H High pressure side P High pressure

Claims (2)

A secondary seal (2) with a resin seal lip (3) is disposed on the high-pressure side (H) of the O-ring (1) as a main seal for high-pressure gas sealing, and the secondary seal ( 2. A high-pressure gas-sealing structure, characterized in that the opening groove (4) of 2) is disposed so as to face the O-ring (1). The high-pressure gas sealing structure according to claim 1, wherein the high-pressure gas is high-pressure hydrogen gas.

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