JP4239487B2 - Self-tightening method for ultra-high pressure vessel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-tightening method and apparatus for an ultra-high pressure vessel.
[0002]
[Prior art]
An industrial process operated at pressures up to 343 MPa (35 Kg / mm ² ) is a low density polyethylene production plant.
[0003]
Even if the cylinder of the ultra-high pressure compressor that generates this gas pressure adopts high tensile strength steel and the wall thickness is infinite, the circumferential stress near the inner circumference becomes excessive, so it cannot be used as it is, and some stress reduction Measures must be taken.
[0004]
As a method of reducing the stress in the vicinity of the inner circumference, (1) a method of generating a compressive stress in the inner cylinder as a multiple shrink-fitting structure, (2) unloading after applying a pressure at which the material yields to a predetermined thickness, There is a method of generating residual compressive stress in the vicinity of the inner periphery plastically deformed using the restoring force of the partial elastic region (self-adhesive treatment method).
[0005]
Japanese Patent Application Laid-Open No. 10-78175 discloses a high pressure composed of a thick and thin metal tube for the purpose of increasing the fatigue strength of the inner peripheral surface of the high pressure fuel rail without depending on the shape of the flow passage. A method for manufacturing a high-pressure fuel rail is described in which the inner surface of a flow passage through which high-pressure fuel flows in the fuel rail is formed by a residual surface of compressive stress.
[0006]
Furthermore, in this publication, water, hydraulic hydraulic oil, etc. can be used as the fluid used for pressurization. However, when the cleaning liquid is used, the inside of the rail material can be cleaned at the same time when the high-pressure fluid is jetted and pressurized. It is. In addition, the pressure applied to the inner circumference of the rail material of the high-pressure fluid is preferably higher than the pressure exceeding the yield point of the inner surface of the rail material flow path, and is preferably large as long as the flow path is not damaged. As a result of the actual analysis of the present inventors, it was confirmed that the pressure at which 25% to 75% of the wall thickness yielded was optimal. Are listed.
[0007]
[Problems to be solved by the invention]
Depending on the conventional self-tightening method, a large force is required to close the end of the cylinder when the inner diameter is large, such as the cylinder (processed part) of the ultra-high pressure compressor used in the low density polyethylene manufacturing plant described above. Needed. For example, when the inner diameter of the cylinder is 100 mm and the load pressure for self-tightening treatment is 500 MPa, the force for closing the end portion is 3900 KN, and there is a problem because the equipment needs to be large.
[0008]
In view of this point, the present invention does not require large-scale equipment when the inner diameter of the component to be processed is large, and generates and retains residual compressive stress on the inner peripheral surface of the seal hole of the component to be processed by a simple method. An object of the present invention is to provide a self-tightening method and apparatus for an ultra-high pressure vessel.
[0009]
[Means for Solving the Problems]
In the present invention, the self-tightening process is performed by applying an ultra-high pressure by passing the seal rod through a seal hole of a component to be processed, for example, a cylinder, with the O-ring attached to the seal rod forming the O-ring groove. A method of applying to an inner peripheral surface is provided. In addition, according to the present invention, in this case, O-rings are installed twice, and an intermediate pressure is sealed between these O-rings.
[0010]
In the present invention, ultra-high pressure refers to a pressure of 500 MPa or more, and provides a self-tightening method by applying a pressure of 500 MPa or more, particularly on the inner peripheral surface of a seal hole of a cylinder having a large diameter of 100 mm or more. Provided is a method for remaining a residual compressive stress by self-tightening treatment.
[0011]
Specifically, the present invention relates to a self-tightening method for an ultra-high pressure vessel in which a pressure of 500 MPa or more is applied to a cylindrical ultra-high pressure vessel to perform self-tightening treatment. A sealing rod in which an installation O-ring groove is formed, a hole opening on the circumference of both O-ring grooves, and a communication path communicating with the external pressure source is formed; With the O-rings attached to both O-ring grooves, the O-rings are attached to the circular seal holes of the ultra-high pressure vessel so that the respective O-rings are in contact with the inner peripheral surface of the circular seal hole, By applying a pressure of 500 MPa or more to the inner circumferential surface of the circular seal hole between the two O-rings and unloading (releasing) the pressure, the inner wall subjected to self-tightening treatment on the inner circumferential surface of the circular seal Provided is a self-tightening method of an ultra-high pressure container to be formed.
[0012]
Further, according to the present invention, each of the ring grooves is composed of a plurality of grooves, other holes are formed between the grooves, and the holes communicate with other pressure sources. A self-tightening method for an ultra-high pressure vessel in which a communication path is formed in the seal rod and an intermediate pressure lower than 500 MPa and higher than atmospheric pressure is simultaneously applied between the plurality of grooves when the pressure of 500 MPa is applied. provide.
[0013]
Furthermore, the present invention provides a self-tightening method for an ultra-high pressure vessel in which a shallow depression is formed on the inner circumferential surface of the circular seal hole and / or a shallow depression is formed on the circumferential surface between the O-ring grooves. provide.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a state in which a seal rod (seal piece) 2 is inserted through a circular seal hole 10 of a cylinder 1 that is a component to be processed. O-ring grooves 11 (11a, 11b, 11c, 11d in this order from left to right) are formed on the circumferences of both ends 2a, 2b of the seal rod 2, respectively. In the case of this example, four are formed as shown in the figure. O-rings 3 (3a, 3b, 3c, 3d in order from left to right) are mounted in these O-ring grooves 11, respectively , and as shown in the figure, the O-rings 3b and 3c are O-rings arranged on the inner side. , O-rings 3a and 3d are O-rings arranged outside.
[0015]
A shallow recess 5a is formed on the central surface of the circular seal hole 10, and a shallow recess 5b is formed on the central surface of the seal rod 2. A processing pressure pressurizing chamber 5 is formed by both. The formation of the processing pressure chamber 5 is not essential, but when the seal rod 2 is attached to the circular hole 10 with the O-ring 3 attached, it should be provided to reduce damage by the inner surface of the seal hole. It may be.
A hole 12 opening in the processing pressure pressurizing chamber 5 is formed. The hole 12 opens toward the circular seal hole 10 when the processing pressure pressurizing chamber 5 is not provided.
[0016]
Small intermediate pressure chamber 6 (6a, 6b) between the sealing O-ring 3 a and 3b of the inner arrangement which is formed on the rod 2, and the outer arrangement 3c and 3d are formed, faces the circle diameter seal bore 10 To do. Even if this intermediate pressure chamber 6 is not formed, it is possible to apply an intermediate pressure between the O-rings 11a and 11b and 11c and 11d.
[0017]
Pressure pressurizing holes 4 and 7 are formed in the end portions 2a and 2b. That is, the end 2a is provided with an intermediate pressure pressurizing hole 7a, and the end 2b is provided with an intermediate pressure pressurizing hole 7b and a processing pressure pressurizing hole 4.
The processing pressure pressurizing hole 4 is communicated with the hole 12 by a communication path 13 that is a pressure path provided in the seal rod 2, and the intermediate pressure holes 7 a and 7 b are also communication paths that are pressure paths provided in the seal rod 2. The passages 14 (14a, 14b) communicate with the intermediate pressure chambers 6a, 6b, respectively.
As will be described later, these communication passages 13 and 14 become communication passages that communicate with an external pressure source.
[0018]
FIG. 2 shows an example in which the O-ring 3 is mounted in the O-ring groove 11. In this case, an inclined surface 111 is formed in the O-ring groove 11 in the direction of load pressure (indicated by an arrow). That is, the inclined surface is provided on the atmosphere side. As a result, when pressure is applied to the O-ring 3, the O-ring 3 is deformed along the inclined surface 111, and the entire O-ring 3 shares the load pressure. The inclined surface 111 is particularly effective in a case such as a large cylinder having a circular diameter of 100 mm or more of a high-pressure compressor and when a self-tightening pressure of 500 MPa or more is applied.
[0019]
The mounting of the seal rod 2 to the cylinder 1 can be accurately performed by the positioning plate 8 provided on the seal rod 2 coming into contact with the side surface of the cylinder 1. FIG. 3 shows a state in which the processing pressure P and the intermediate pressure Pm are loaded. Pressurizing pumps 21 and 22 are disposed outside as pressure sources, and are connected to the processing pressure pressurizing hole 4 and the intermediate pressure pressurizing holes 7a and 7b by pipes 23 and 24 (24a and 24b), respectively.
[0020]
A processing pressure P ≧ 500 MPa is generated by the pressurizing pump 21, and an intermediate pressure Pm (0.3 P to 0.5 P) is generated by the pressurizing pump 22. The intermediate pressure is generated as an intermediate pressure between the processing pressure and the atmospheric pressure.
A processing pressure P is applied between the O-rings 3b, 3c, and an intermediate pressure Pm is applied between the O-rings 3a, 3b, 3c, 3d. In this case, the pressurizing medium may be a liquid obtained by mixing 50% each of non-ignitable ethylene glycol and water.
[0021]
FIG. 4 shows the state of occurrence of stress when the processing pressure is applied and self-tightening processing is performed. On the left side, the situation where tensile stress and plastic deformation region are generated by applying pressure above the yield point of the cylinder material is shown, and on the right side, the situation where residual compressive stress remains when the processing pressure is unloaded is shown. As shown in FIG. 4, when the processing pressure is unloaded, residual compressive stress remains in the vicinity of the circumferential surface of the circular seal hole of the cylinder 1, that is, on the circumferential wall. As a result, self-tightening processing is performed between the O-rings 3b and 3c. According to this, it is possible to generate a residual compressive stress in the vicinity of the inner periphery without adopting a double shrink fitting structure.
[0022]
As shown in FIG. 5, in the case of this example, two O-ring grooves are provided in the seal rod 2, and the intermediate pressure chamber 6 is provided therebetween. An intermediate pressure is applied to the intermediate pressure chamber 6 through the intermediate pressure pressurizing hole 7 to reduce the load per O-ring. For example, when the processing pressure is 500 MPa, if the intermediate pressure is set to 200 MPa, the load on the O-ring on the high pressure side becomes a difference of 300 MPa between the processing pressure and the intermediate pressure.
[0023]
As described above, according to the present embodiment, in the self-tightening method of the ultra-high pressure vessel in which a pressure of 500 MPa or more is applied to the cylindrical ultra-high pressure vessel to perform the self-tightening treatment, on the circumferences of both ends, are inclined surfaces in the load acting direction in O-ring groove of the O-ring arrangement設用each forming a hole portion which opens on the circumference between the two O-ring grooves, and communicates with the hole portion, communicates with an external pressure source The O-ring is inserted into the circular seal hole of the cylinder having a circular diameter of 100 mm or more of the ultra-high pressure vessel in a state where the O-ring is mounted in both the O-ring grooves. Wearing in contact with the inner peripheral surface of the seal hole, applying a pressure of 500 MPa or more to the inner peripheral surface of the circular seal hole between the O-rings through the communication path, and releasing the pressure. The self-adhesive treatment is performed on the inner peripheral surface of the circular seal. Be one that forms an inner wall, in this case, the both ring grooves respectively shall consist of a plurality of grooves to form other holes that respectively open during each of a plurality of grooves, said other hole A communication passage communicating with another pressure source is formed in the seal rod, and when the pressure of 500 MPa is applied to the inner peripheral surface of the inner diameter seal hole, the pressure is lower than 500 MPa between the plurality of grooves at the same time. A self-tightening method for an ultra-high pressure vessel that loads a higher intermediate pressure is configured.
[0024]
According to this embodiment, since the seal rod 2 penetrating the inner diameter portion of the component to be processed is installed, the thrust generated in the seal portion on one side and the thrust generated in the seal portion on the opposite side are balanced. There is no need to firmly fix the rod 2. Moreover, since the pressure receiving area in the axial direction can be reduced and the thrust can be reduced by passing the seal rod 2 through the circular seal hole 10 which is the circular diameter portion of the part to be processed, the seal rod 2 is generated. Stress can be reduced.
[0025]
On the other hand, since it becomes impossible to attach an endless delta ring by penetrating the seal rod 2, an inclination is provided on the surface of the O-ring groove 11 on the atmosphere side so that the O-ring 3 is covered when pressure is applied. By concentrating in the gap between the inner diameter of the processing component and the outer diameter of the seal rod 2, the pressure resistance can be improved by adopting a structure that receives pressure in the entire O-ring.
[0026]
However, when a pressure is applied to the component to be processed, the component to be processed expands and a gap with the seal rod 2 increases, so that the O-ring 3 may be broken at a certain pressure. Therefore, in this embodiment, O-rings are installed twice, and by sealing an intermediate pressure between these O-rings 3, that is, an intermediate pressure between the load pressure and the atmospheric pressure, per O-ring. The pressure resistance performance as a whole can be improved.
[0027]
【The invention's effect】
As described above, according to the present invention, in a process of applying a pressure of 500 MPa or more, such as a self-tightening process applied to a cylindrical ultrahigh pressure vessel, a large structure is not required, and high pressure is sealed with a simple structure. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration for carrying out a self-adhesive processing method according to an embodiment of the present invention.
FIG. 2 is a partial detail view of FIG. 1;
FIG. 3 is a diagram showing a state in which the self-adhesive processing method according to the embodiment of the present invention is performed.
FIG. 4 is a diagram showing generation of residual compressive stress.
FIG. 5 is a diagram showing an operation by applying an intermediate pressure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processed part (cylinder), 2 ... Seal rod, 3 ... O-ring, 4 ... Processing pressure pressurization hole, 5 ... Processing pressure pressurization chamber, 6 ... Intermediate pressure chamber, 7 ... Intermediate pressure pressurization hole, 8 ... Positioning Plates 10... Circular seal holes, 11... O-ring grooves, 13 and 14.

Claims (4)

In the self-tightening method of the ultra-high pressure container, in which a pressure of 500 MPa or more is applied to the cylindrical super-high pressure container to perform the self-tightening process,
Both end portions respectively form the O-ring groove of the O-ring arrangement設用on the circumference of, communicating hole which opens on the circumference, and the holes section between the two O-ring grooves, communicating with the external pressure source The seal rod formed with the communicating passage is in contact with the circular seal hole of the ultra-high pressure vessel with the O-rings installed in both O-ring grooves, and the respective O-ring contacts the inner peripheral surface of the circular seal hole. The circular seal inner periphery is loaded by applying a pressure of 500 MPa or more to the inner peripheral surface of the circular seal hole between the O-rings through the communication path and unloading the pressure. An inner wall subjected to self-adhesive treatment on the surface , wherein both the ring grooves are composed of two grooves of an inner arrangement and an outer arrangement, respectively, and an O-ring is mounted on each of the two grooves, Form other holes that open between them, A communication passage that communicates another hole with another pressure source is formed in the seal rod, and when the pressure of 500 MPa or more is applied between the O-rings disposed at the inner sides of both ends, the inner and outer configurations are simultaneously disposed. A self-tightening method for an ultra-high pressure vessel , wherein an intermediate pressure lower than 500 MPa and higher than atmospheric pressure is applied between the grooves . Oite to claim 1, the self-frettage treatment method of ultra high pressure vessel, characterized in that the formation of the shallow recess in the circle diameter seal bore periphery. 3. The self-tightening method for an ultrahigh pressure vessel according to claim 1, wherein a shallow depression is formed on an inner peripheral surface between the two O-ring grooves. In the self-tightening method of the ultra-high pressure container, in which a pressure of 500 MPa or more is applied to the cylindrical super-high pressure container to perform the self-tightening process,
On the circumference of both ends of the cylinder having an inner diameter of 100 mm or more, an inclined surface is formed in the load acting direction in the O-ring groove for disposing the O-ring, and a hole opening on the circumference between both O-ring grooves, And a sealing rod formed with a communication path communicating with the external pressure source, and with the O-rings in both O-ring grooves, respectively, into the circular-diameter sealing holes of the ultrahigh-pressure vessel, respectively. Is mounted in a state where the O-ring is in contact with the inner peripheral surface of the circular seal hole, and a pressure of 500 MPa or more is applied to the inner peripheral surface of the circular seal hole between the O-rings through the communication path, By unloading the pressure, an inner wall subjected to self-tightening treatment is formed on the inner peripheral surface of the circular seal, and in this case, the two ring grooves are each provided with two grooves of an inner arrangement and an outer arrangement. Each consisting of two grooves Other hole portions that are respectively opened in between are formed, a communication passage that communicates the other hole portions with other pressure sources is formed in the seal rod, and the pressure of 500 MPa or more is provided between the O-rings disposed on the inner sides of both ends. A self-tightening method for an ultra-high pressure container, wherein an intermediate pressure lower than 500 MPa and higher than an atmospheric pressure is simultaneously applied between the inner and outer grooves when simultaneously applying pressure.

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