JP2003294144A - Screw-topped high pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw-topped high pressure vessel that reduces the maximum value of load generated on the bottom side of the screw top and has a long life by combining a taper screw and a parallel screw in a longitudinal direction of the screw portion. <P>SOLUTION: The shape of a male screw portion or a female screw portion of a screw portion where the male and female screws are screwed is made different, so that the load distribution generated on the screw portion, due to inner pressure of the vessel, has at least a plurality of load concentration portions with one or more load concentration portions, having average load or more at an end of the screw portion on the inner pressure side and a position halfway in a longitudinal direction of the screw portion. Concretely, of the male screw and the female screw at the screw portion, at least either screw has one or plurality of taper screws on the bottom side of the screw top to which inner pressure is applied, and a parallel screw on the upper side of the screw top, and the screws are coupled to each other. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a screw-cap type high-pressure container, and in particular, an internal screw is threaded on the container body side and a male screw is threaded on the screw lid side, and both are screwed to each other to axial force by internal pressure. The present invention relates to a screw-cap type high-pressure container for holding.

[0002]

2. Description of the Related Art Conventionally, a screw lid type high-pressure container is known in which a female screw is engraved on the container body side and a male screw is threaded on the screw lid side and both are screwed to retain axial force due to internal pressure. FIG. 5 is a sectional view showing an example of a conventional screw lid type high pressure container. The screw lid type high-pressure container 40 includes a container body 41, a screw lid 42 that is supported so as to be horizontally rotated, and a screw portion 43 that is formed so as to face and face the container body side and the lid side.
Equipped with. The threaded portion 43 has a female threaded portion on the inner circumference on the opening side of the container body 41 and a male thread on the circumferential surface side of the threaded lid. The threaded lid 42 is horizontally rotated to screw both threaded portions together. The axial force is maintained by the internal pressure.

FIG. 6 (A) is a detailed view of the threaded portion 43 shown in a horizontal direction by enlarging the VI portion of FIG. 5, and FIG. 6 (B) is its threaded portion 4.
It is the load distribution diagram shown corresponding to FIG. In FIG. 6, the screw portion 43 of the conventional screw lid type high-pressure container 40 includes a female screw 44 on the container body 41 side and a male screw 45 on the screw lid 42 side.
The whole is formed by parallel threads. Reference numeral 46 is a ring seal provided on a portion of the screw lid 42 facing the inner wall of the container body 41, and 47 is a seal pressing ring.

When the male screw portion of the screw lid 42 is screwed onto the female screw portion of the container body 41 to hermetically seal (close) the inside of the container (closed), the male screw on the screw lid side formed in parallel 45 and the female screw 44 on the container body side are intermeshed with each other over the entire length of the screw portion 43. Generally, the high-pressure vessel 40 is operated in this closed state while repeatedly maintaining the internal pressure at high pressure and normal pressure for a predetermined time. When a high pressure is applied to the high pressure container 40, a uniform distribution of the internal pressure P is applied to the inner surface of the screw lid 42. Since the internal pressure P in the container is applied to the inside (bottom side) of the screw lid 42 in the state where the screw portion 43 is engaged, the screw lid 4
A compressive force is generated in 2 and a tensile force is generated in the container body 41 at the same time.

[0005]

At this time, the threaded portion 43 is formed.
Is a parallel screw and evenly meshed over the entire length.
As shown in the load distribution diagram of No. 2, it is clear that the maximum load concentration due to the load of the internal pressure P occurs at the innermost end of the screw portion 43, and the load decreases in a catenary shape as it approaches the upper surface of the screw lid 42. Has become. Since the magnitude and distribution tendency of the stress proportional to the load causes the maximum load concentration due to the load of the internal pressure P at the innermost end of the threaded portion 43, even if the thread length is increased, The fact that the length is almost the damping load does not improve is obvious from the fact that the screw tip hardly bears the load.

In the load distribution diagram of FIG. 6 (B), the screw portion 43
The load distribution in the length direction is represented by a coefficient with respect to the average load. In the conventional screw lid type high-pressure container, a concentrated load of 4.819 times the average load is generated at the innermost end of the screw portion 43. Therefore, when a high pressure is repeatedly applied to the bottom of the screw lid 42 from the inside, the threaded portion 43 is fatigued due to the repeated high load stress on the bottom side of the screw lid, which shortens the life of the screw type high-pressure container. Further, if the yoke lid type opening / closing lid is used instead of the screw lid structure, there is a problem that the equipment becomes large and the cost becomes high.

In view of the above problems, the present invention provides a screw lid type high-pressure container having a long life by reducing the maximum load generated on the bottom side of the screw lid by combining a taper screw and a parallel screw in the lengthwise direction of the screw portion. The purpose is to do.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, according to the present invention, a female screw is formed in the opening on the container body side, and a male screw is formed in the screw lid side. In a screw-cap type high-pressure container that holds force, the invention according to claim 1 is such that a load distribution formed in a screw part where the male screw and the female screw are screwed by the internal pressure applied to the container is a screw part on the container internal pressure side. Along with the terminal end, one or more load concentrating portions having an average load or more are formed at an intermediate position in the lengthwise direction of the screw portion, and the shape of the male or female thread is varied so that the load distribution has at least a plurality of load concentrating portions. It is characterized by that. According to this invention, not only one load concentration portion is concentrated at the end of the threaded portion on the container internal pressure side, but one or more load concentration portions having an average load or more are formed at an intermediate position in the threaded portion length direction, and at least a plurality of load concentration portions are formed. The load distribution having the load concentrating portion, specifically, as shown in FIGS. 2 and 4, a sawtooth-shaped load distribution can be formed, and the maximum load is significantly reduced accordingly.

As a specific means for forming a load distribution having a plurality of load concentrating portions as described above, in claim 2, at least one screw side of the male screw and the female screw located at the screw portion receives internal pressure. The lid bottom side is formed by one or a plurality of taper screws, the screw lid upper side is formed by parallel threads, and the threads are continuously formed. In this case parallel threads are good on the other side,
Specifically, a combination of female threads or male threads with parallel threads and male threads or female threads with “taper threads + parallel threads” is preferable. In this case, taper threads have a maximum pitch diameter at the boundary that is the same as the pitch diameter of the parallel threads. It is tapered more than that.

Preferably, the parallel female (male) screw linearly provided on the high-pressure container body or the screw lid side and the screw lid outer periphery (inner periphery of the high-pressure container body) so as to mesh with the female (male) screw. It is composed of a parallel screw provided on the upper part and a male (female) screw having one or a plurality of taper screws provided on the outer periphery of the screw lid (inner periphery of the main body of the high pressure container) connected to each other, and as shown in FIG. The plurality of taper threads are connected to the end of the threaded portion on the container internal pressure side and a plurality of taper threaded portions with taper angles set so that the second load concentration portion is formed at the boundary position of the plurality of taper threads. It is better to let them do it.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, unless otherwise specified, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

FIG. 1 is an explanatory view of a screw portion structure of a screw lid type high pressure container according to the first embodiment of the present invention, FIG.
1 is a sectional view (A) of the screw portion of the screw-cap type high-pressure container and a load distribution diagram (B) of the screw portion in this embodiment. FIG. 3 is a diagram showing the amplitude of the stress intensity generated in the high-pressure container and the repeated stress. It is a graph which shows the relationship with a number. As is clear from FIG. 1, in the present embodiment, the screw portion 1 of the screw lid type high pressure container 10 is provided.
3 is a parallel female screw 21 provided in a straight cylindrical shape on the inner peripheral side of the circumferential opening 11a of the container body 11, and a parallel screw portion 2 provided on the screw lid 12 side with respect to the parallel female screw 21 on the container body 11 side.
3 and a male screw 22 including a taper screw portion 24.

The parallel screw portion 23 is provided on the outer peripheral upper portion of the screw lid 12, and the screw lid 1 is fitted so as to fit tightly with the female screw 21 side.
(2) From the upper end of the outer circumference, screw down to a position where it hangs downward about 30 to 50% (relative to the total length). The taper screw portion 24 connected to the lower side of the screw lid 1 extends from the end of the parallel screw portion 23 located on the upper side toward the lower end side of the screw lid 12.
2 From the outer peripheral middle stage position to the position where it engages with the end of the internal thread 21. That is, in FIG. 1, 21 is a parallel female screw formed on the container body 11 side in a vertical or linear cross section, and 22 is an upper parallel screw portion 23 (about 30%) formed on the lid 11 side so as to be screwed into the female screw 21. Length) and a taper screw portion 24 (a length of about 50 to 70%) on the lower side thereof are gradually reduced in outer diameter toward the lower side to form a continuous male screw.

The upper parallel thread portion 23 on the male screw 22 side is parallel to the female screw 21 and has a constant length (about 3 mm) from the head of the screw lid 12.
0 to 50%), and is then continuously slanted to the parallel threaded portion 23 and slightly inclined away from the female thread 21, that is, the diameter is gradually reduced as it goes downward and is slightly tapered. The taper screw portion 24 (about 50 to 70%) is formed, and the entire length of the male screw 22 is formed. 25 is a parallel thread 23
And the taper screw portion 24 (the pitch diameter and the outer diameter of the parallel screw portion 23 and the taper screw portion 24 are made to coincide with each other at this portion), α is 1 / the taper angle of the taper screw portion 24.
It is 2. At the location where the internal thread 21 and the taper thread 24 face each other, the vertical gap δ between the internal thread 21 and the taper thread 24 gradually increases as the length of the taper thread 24 below the boundary line 25 increases. This gap δ increases as the taper angle 2α increases, and decreases as the taper angle 2α decreases.

In the screw-cap type high-pressure container 10, the high-pressure container 1 in which the opening 11a of the container body 11 is closed with a screw lid.
Consider the internal pressure P on the way that the inside of 0 is loaded with a high pressure. The screw lid 12 receives a compressive stress (-
[sigma] _B ) is generated, and along with this, tensile stress ([sigma] _N ) in the opposite direction is generated in the container body 11. At this time, when the contraction on the male screw side due to compression is ΔB = (σ _B / E) × X and the elongation on the female screw side due to tension is ΔN = (σ _N / E) × X,
The vertical gap δ between the internal thread 21 and the taper threaded portion 24 at the distance X from the boundary line is expressed by δ = [ΔB = (σ _B / E) × X] + [ΔN = (σ _N /
If the taper angle 2α is set so that E) × X] = 0, the gap δ is canceled when the high pressure container 10 is under a high pressure load, and the tips of the taper screw portion 24 mesh with the female screw 21 uniformly. Like

2A, when the length of the male screw 22 on the screw lid 12 side is L in this type, the length of the parallel screw portion 23 is 1/2 L and the length of the taper screw portion 24 is 1 / L. This is the case when configured to 2L. Reference numeral 26 is the tip screw tooth position of the taper screw portion 24. The lengths of the parallel thread portion 23 on the male screw 22 side and the taper thread portion 24 are not limited to two equal parts, and may be provided to be different to some extent. In addition, the taper screw is a female screw 21
Even if the parallel screw is provided on the side of the male screw 22, the effect does not change.

Next, FIG. 2 and FIG. 3 show the load distribution diagram of the screw portion in the first embodiment of the present invention, and the relationship between the amplitude of the stress intensity generated in the high-pressure container and the number of repetitions of the generated stress. As can be understood from FIG. 2A, when the male screw portion 22 of the screw lid 12 is screwed into the female screw portion of the opening 11 a of the container body 11 to close the high-pressure container 10, the parallel screw portion 23 on the male screw upper 22 side. Only the female screw 21 (parallel screw) meshes with the taper screw portion 24 on the lower side of the male screw 21 and the female screw 21 does not mesh. At this time, the gap δ of the taper screw portion 24 is proportional to the distance X in the length direction toward the bottom side (left side in the drawing), and δ
= KX. When the internal pressure is applied to the high-pressure container 10, the compressive stress σ _B acts on the male screw 22 side and the tensile stress σ _N acts on the female screw 21 side in proportion to the internal pressure P, and the total displacement thereof is ΔN + ΔB = [(σ _N / E) × X] + [(σ _B / E) × X]
And is proportional to X. As the internal pressure increases, δ = kX = ΔN + ΔB at a certain pressure, the gap δ is canceled, and the female screw 21 and the taper screw portion 24 on the male screw side mesh with each other. The increase in load due to the subsequent pressure increase is due to the parallel thread portion 23.
The entire screw of the taper screw portion 24 will bear the load.

At this time, as shown in the load distribution chart of FIG. 2, the compressive stress σ _B acting on the screw lid 12 side due to the internal pressure P.
Is generated in each of the parallel thread portion 23 and the taper thread portion 24 at the terminal end thereof, and a load curve that gradually attenuates upward from the concentration portion is generated in parallel. Then, by appropriately adjusting the taper angle 2α of the taper screw portion 24, the load generated by the parallel screw portion 23 and the taper screw portion 24 can be made uniform.
%, The remaining load of 53% including the taper thread portion 24 minutes can be supported. Therefore, the maximum load generated in the male screw 22 is divided into two positions, that is, the boundary line 25 position of the tip of the parallel screw part 23 and the tip screw tooth position 26 of the taper screw part 24, and is generated as almost equal maximum loads. The maximum load value decreases to about 2.54 times the average load. When this maximum load value is compared with the conventional device of FIG. 6, the load reduction rate is (4.819-2.54) /4.819=about 47%.

FIG. 3 is a known graph showing the relationship between the amplitude of internal stress intensity generated in a high-pressure vessel and the number of stress generation cycles, which is published by the Japan High Pressure Technology Association. On this graph, comparing the stress generated by the conventional device of FIG. 6 with the stress generated by the device of FIG. 2 of the present invention, the generated stress amplitude is 686N.
/ Mm ² {70 kgf / mm ² }, the conventional device of FIG.
In the apparatus of FIG. 2 of the present invention in which the generated load is reduced by 47%, the allowable number of repeated cycles of the generated stress is 40,000, and it can be understood that the life of the apparatus can be extended 40 times that of the conventional one. When the length of the parallel screw portion 23 on the side of the male screw 22 and the length of the taper screw portion 24 are different, the maximum stress value becomes larger on either side than the other, but the magnitude of the maximum load value is significantly larger than that of the conventional one. It is possible to reduce the allowable number of repetitions of stress and the life of the device as well.

FIG. 4 is a sectional view of a screw portion corresponding to FIG. 2 of a screw lid type high-pressure container according to a second embodiment of the present invention having a taper screw in two stages, and a load distribution diagram of the screw portion in this embodiment. is there. In this embodiment, with respect to the total length L of the female screw and the male screw, the length of the male screw lower taper screw portion of the screw lid is larger than the length of the parallel screw portion, and the taper angle 2α is adjusted so that the taper screw portion acts in two steps. This is the case when it is configured with.
In FIG. 4, 33 is a parallel thread portion provided at a length of 4/10 of the length L of the male thread 22, and 34a and 34b are parallel thread portions 3
3 / 10L length two-step taper screw part provided in succession, specifically taper screw part 34a following parallel screw
Has a taper angle smaller than that of the taper screw portion 34b in the lower stage, for example, the taper angle 2α1 of the taper screw portion 34a is 1/2 of the taper angle 2α2 of the taper screw portion 34b in the lower stage.
Is set to. 35 is the boundary line position of the tip of the parallel screw part 33, 36a is the boundary line position of the tip of the taper screw part 34a, 3
6b is a tip position of the taper screw portion 34b. The length of the parallel screw portion 33 and the length of the taper screw portions 34a and 34b are not limited to the above, and may be provided at an appropriate ratio. Also,
The number of taper threads may be three or more instead of two.
Other configurations may be similar to those in the first embodiment. According to this embodiment, as shown in the load distribution chart of FIG. 4, the taper angles of the taper screw portions 34a and 34b are set to be appropriate, preferably α2.
By setting> α1, the parallel thread portion 33 and the taper thread portion 3
It is possible to equalize the loads generated at the portions 4a and 34b, and for example, 29% of the load can be taken by the parallel thread portion 33 minutes, 31% of the load by the taper screw portion 34a, and 40% of the load by the taper screw 34b portion. As a result, the maximum load generated on the male screw 22 side is 3 at the boundary line 35 position of the parallel screw portion 33 tip, the taper screw portion 34a tip screw tooth position 36a position, and the tip screw tooth position 36b position of the taper screw 34b. The maximum load value is divided into several parts and occurs as an almost uniform maximum load value, and the maximum load value decreases to about 1.98 times the average load. Comparing this maximum load value with the conventional device of FIG. 6, the load reduction rate is (4.819-1.98) /4.819=about 59%. On the other hand, when the amplitude of the stress intensity is plotted in the graph of FIG. 3 from this load reduction rate, the allowable repetition rate of the generated stress is 550,000 in the FIG. 4 apparatus of this example.
As a result, the life of the device can be extended to 550 times that of the conventional one. The length of the parallel screw portion 33 and the taper screw portion 34a, 3
The same applies when the length of 4b is changed.

As described above, according to the present invention, by combining a taper screw and a parallel screw in the thread length direction, the maximum load generated on the bottom side of the screw lid is reduced, and the screw lid type with a long life is provided. A high-pressure container can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a screw portion configuration of a screw lid type high pressure container according to a first embodiment of the present invention.

FIG. 2 is a sectional view (A) of a screw portion of a screw-cap type high-pressure container according to the first embodiment of the present invention and a load distribution diagram (B) of the screw portion in this embodiment.

FIG. 3 is a graph showing the relationship between the amplitude of stress intensity generated in a high-pressure container and the number of times stress is generated.

FIG. 4A is a sectional view of a screw portion corresponding to FIG. 2 of a screw-cap type high-pressure container according to a second embodiment of the present invention, and FIG. 4B is a load distribution diagram of the screw portion in this embodiment. .

FIG. 5 is a cross-sectional view showing an example of a conventional screw lid type high pressure container.

6A is a detailed view of a threaded portion 43 shown in a horizontal direction by enlarging a VI portion of FIG. 5, and FIG. 6B is a load distribution chart shown in correspondence with the threaded portion 43.

[Explanation of symbols]

10 Screw lid type high pressure container 11 container body 12 screw lid 13 screw part 21 Container body side parallel female screw 22 Male screw on the lid side 23 Parallel screw on upper side 24 Tapered threads that are slightly tapered 25 border 11a Container body opening 33 Parallel thread 34a, 34b Tapered screw part 35 Boundary line position 36a border position

Claims (4)

[Claims] 1. A high-pressure container of a screw lid type in which a female screw is threaded into an opening on the container body side and a male screw is threaded into a screw lid side, and both are screwed to retain an axial force due to an internal pressure. The load distribution formed in the screw part where the male screw and the female screw are screwed by the internal pressure applied to the container is such that at the end of the screw part on the internal pressure side of the container, one or more load concentrating parts with an average load or more are formed in the middle position in the screw part length direction. The screw-cap type high-pressure container is characterized in that the shape of the screw portion of the male screw or the female screw is different so that the load distribution has at least a plurality of load concentrating portions. 2. A screw lid-type high-pressure container in which an internal thread is screwed into an opening on the container body side and a male screw is threaded into a screw lid side, and both are screwed to hold an axial force due to an internal pressure, wherein the screw part is provided. At least one of the male screw and the female screw located on the inner side is formed with one or a plurality of taper screws on the bottom side of the screw lid to which the internal pressure is applied, and the parallel side screw is formed on the upper side of the screw lid, and the respective screws are connected to each other. A screw-cap type high-pressure container characterized by being installed and formed. 3. A parallel female (male) screw linearly provided on the high-pressure container main body or the screw lid side, and an upper part of the screw lid outer periphery (inner periphery of the high-pressure container main body) so as to mesh with the female (male) screw. The parallel screw provided and a male (female) screw in which one or a plurality of taper screws provided on the lower portion of the outer circumference of the screw lid (inner circumference of the high-pressure container main body) are connected, and the screw is formed.
Alternatively, the screw-cap type high-pressure container described in 2. 4. The taper angles of the plurality of taper screws according to claim 3 are set such that a second load concentrating portion is formed at a boundary position of the plurality of taper screws together with the end of the screw portion on the container internal pressure side. 4. The screw-cap type high-pressure container according to claim 3, wherein the plurality of taper screw portions are continuous.