JP2007210325A - Method for manufacturing frp cryostat and frp cryostat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an FRP cryostat by bonding a plurality of members which ensures the strength of bonded portions of the respective members, is strong against mechanical shock and thermal shock, and is less prone to the occurrence of vacuum leak, and an FRP cryostat manufactured according to the manufacturing method. <P>SOLUTION: The method for manufacturing an FRP cryostat comprises a member manufacturing process of manufacturing each of a plurality of FRP members 11a, 11b, a taper forming process of forming tapered surfaces 12a, 12b on outer surfaces near bonded portions of the respective FRP members, an overlapping piece forming process of forming overlapping pieces 13a, 13b for overlapping both end surfaces of the FRP members inside and outside, respectively, a member bonding process of overlapping the overlapping pieces of the respective FRP members to be bonded, a prepreg laminating process of attaching prepregs on both tapered surfaces of bonded FRP members to be laminated, and a prepreg curing process of deaerating the laminated prepregs to thereby cure the prepreg. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cryostat made of FRP, and more specifically, a method for manufacturing a cryostat made of FRP (fiber reinforced plastic) for storing a low temperature fluid such as liquid nitrogen or liquid helium, and a product made of FRP manufactured by this manufacturing method. Related to cryostat.

A cryostat used for cooling a superconducting magnet or the like cannot be manufactured by integral molding because an object to be cooled such as a superconducting magnet must be placed in the cryostat. In particular, in the case of an FRP cryostat, since it cannot be welded like metal, a bottomed cylindrical container main body serving as the main body of the cryostat, and a plate-like lid member attached to the upper opening of the container main body, These are generally manufactured by bonding them together (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 61-210603

  However, since the glass fiber is interrupted at the bonding portion between the container main body and the plate-like lid member, the glass fiber over the two or more members to be bonded is not woven, and the container has multiple layers of fibers. Compared with the FRP of the main body and the plate-like lid member, the strength is significantly reduced. For this reason, the bonded portion may be peeled off by impact or vibration, and a vacuum leak may occur.

  In order to prevent peeling of the bonded portion, there is a reinforcing measure in which a member to be bonded is screwed and screwed and bonded. However, although the strength is increased to some extent by this method, the strength against the low-temperature vacuum leak due to peeling of the bonded portion cannot be sufficiently improved because the strength is still inferior to the portion where the glass fibers are laminated. In addition, this screwing method can be applied to a cryostat that does not have a directionality like a circular point symmetry, but the cryostat has a position that specifies the accessory parts of the cryostat or a structure that cannot be rotated. Has a restriction that it cannot be applied.

  Including the screwing method described above, the bonding surface between such FRPs is less strong than the part where many glass fibers are overlapped and the fibers are intricate, and it is bonded by mechanical, thermal shock, etc. There is a risk of peeling or cracking of the part. For this reason, the atmosphere or the liquefied gas during storage leaks from the peeled portion into the heat insulating vacuum layer sandwiched between the inner tank and the outer tank, and the performance of the cryostat may not be maintained.

  Therefore, the present invention, when manufacturing a FRP cryostat by joining a plurality of members, ensures the strength of the joint of each member, manufactures an FRP cryostat that is resistant to mechanical and thermal shocks and is less susceptible to vacuum leaks. It is an object to provide a method and a cryostat made of FRP manufactured by the manufacturing method.

  In order to achieve the above object, the FRP cryostat manufacturing method of the present invention is a sealed container-like FRP cryostat manufacturing method for storing a cryogenic fluid, wherein the cryostat is formed by joining a plurality of FRP members. The member manufacturing process for manufacturing each of the FRP members in a preset shape, and the outer surface portion of the FRP member manufactured in the member manufacturing process in the vicinity of the joint part with the other FRP member is directed to the joint part. The taper forming step for forming a thin tapered surface, and the joint part end surfaces of the FRP members to be joined to each other are located at the inner position from the end surface of one FRP member and from the end surface of the other FRP member. A polymerized piece forming step for forming a polymer piece in a protruding state at each position, and forming the tapered surface and the polymerized piece The FRP members are overlapped in the inner and outer directions, and the FRP members are joined to each other, and the prepreg is attached to the taper surfaces of both FRP members that are joined. And a prepreg curing step in which the laminated prepreg is degassed and cured.

  Furthermore, the FRP cryostat manufacturing method of the present invention is characterized in that, in the member joining step, the polymerized surface portion of the polymerized piece is polymerized through an adhesive, and in particular, in the member joining step, After the primary bonding of the joints, an airtight test is performed to confirm that the airtightness is ensured. Further, the FRP member is an upper half and a lower half of a cylindrical container, and in the member joining step in this case, the polymerized piece is made of FRP which becomes the container upper side when in use. It is characterized by polymerizing so that the superposed piece of the member is located outside. In addition, the prepreg curing step is characterized in that the prepreg laminated portion outside the container is evacuated and the inside of the container is pressurized.

  In addition, the FRP cryostat of the present invention includes a member manufacturing process for manufacturing each of a plurality of FRP members in a preset shape, and a joint portion of the FRP member manufactured in the member manufacturing process with another FRP member. A taper forming step of forming a tapered surface that becomes thinner toward the joint portion on the outer surface portion in the vicinity, and the joint portion end surface of the FRP member to be joined to each other at an inner position from the end surface of one FRP member, the other From the end surface of the FRP member, a polymerized piece forming step for forming each of the protruding polymerized pieces at the outer position, and the polymerized surface portion of the polymerized piece of the FRP member formed with the tapered surface and the polymerized piece A prepreg is affixed to the taper surfaces of the joined FRP members, and a member joining step for joining the joined portions of the FRP members together inside and outside. And the prepreg laminating step of laminating a FRP made cryostat manufactured by the method comprising the cured prepreg curing by degassed laminated prepreg.

  According to the present invention, since the joint portion of each member is also laminated and cured, the member main body portion in which the joint portion is covered with multiple layers of glass fiber and does not form a tapered surface A strength close to is obtained. Accordingly, the strength against mechanical shock and thermal shock can be greatly improved, the peeling of the resin and the occurrence of cracks can be prevented, and an FRP cryostat that hardly causes vacuum leak can be manufactured.

  Hereinafter, a procedure for manufacturing a cylindrical FRP cryostat using the FRP member divided into the container upper half and the container lower half will be described. In FIG. 1 to FIG. 10, the drawing is made so that the tapered surface, the superposed piece, etc. are clearly shown, and the display of the unnecessary portions for the explanation is omitted.

  First, as shown in FIG. 1, as a plurality of FRP members constituting the FRP cryostat, an FRP container half 11 made of a bottomed cylindrical body having one open end is manufactured (member manufacturing process). The FRP container half 11 can be manufactured in the same manner as a conventional FRP product, and the manufacturing procedure is not particularly limited. In addition, when the cryostat is vertically symmetric as in a cylindrical shape, two identical FRP container halves 11 may be manufactured.

  Next, as shown in FIG. 2, the outer surface portion in the vicinity of the joint portion of one FRP container half body 11a serving as the lower half portion of the container, that is, the outer peripheral surface in the vicinity of the opening, is gradually moved toward the opening serving as the joint portion. The taper surface 12a is formed by cutting so as to be thin (taper forming step), and the outer peripheral side is cut while leaving the inner peripheral side of the opening end, so that the overlapping piece 13a is formed at the inner position of the joint end surface. Form (polymerized piece forming step).

  On the other hand, as shown in FIG. 3, the other FRP container half 11b, which is the upper half of the container, also cuts the outer peripheral surface near the opening to form a tapered surface 12b (taper forming step), By cutting the inner peripheral side while leaving the outer peripheral side of the opening end, the polymer piece 13b is formed at the outer position of the joint end face (polymerized piece forming step). Further, after forming through holes 14 such as through holes and screw holes for inserting pipes and wires as necessary, the pipes 15 and the like are fixed to the through holes 14 by an appropriate means as shown in FIG. To do. The positions of the through hole 14 and the pipe 15 are not particularly limited, and any part of the FRP container halves 11a and 11b may be used as long as the portion where the tapered surface 12a is formed is avoided.

  It is preferable that the polymer pieces 13a and 13b are formed so that they are in close contact when they are overlapped and the total thickness thereof is the same as the thickness of the end face of the joint. Usually, it is desirable to form each of the polymer pieces 13a and 13b with a thickness that is half the thickness of the end face of the joint. However, even if the polymer piece 13a located on the inner side is thicker than the polymer piece 13b located on the outer side. Good.

  Next, as shown in FIG. 5, the FRP container halves 11a and 11b respectively formed with the tapered surfaces 12a and 12b and the polymerized pieces 13a and 13b are brought into contact with each other to superpose the polymerized pieces 13a and 13b. It joins, superposing | polymerizing a surface part in an inside-out direction (member joining process). At this time, both the polymer pieces 13a and 13b are bonded via an adhesive between the polymer surfaces of the polymer pieces 13a and 13b, that is, the outer peripheral surface of the polymer piece 13a at the inner position and the inner peripheral surface of the polymer piece 13b at the outer position. By performing the primary adhesion for polymerizing the polymer, it is possible to ensure the bonding strength and airtightness of the polymerized portion. In addition, ensuring airtightness means that there are no air bubbles in the overlapping portions of both the polymer pieces 13a and 13b and there is no air passage. If airtightness is not ensured at the time of this primary bonding, it is difficult to ensure sufficient airtightness in the next prepreg lamination step or prepreg curing step. Therefore, it is preferable to perform an airtight test after the completion of the primary bonding to confirm that no leakage occurs, that is, airtightness is ensured.

  When the adhesive is used in this way, it is preferable to provide a bonding margin on the polymerization surface of the polymer pieces 13a and 13b. In addition, the polymer piece 13a at the inner position is disposed below and the polymer piece at the outer position is disposed above. By arranging 13b, it is possible to prevent the adhesive from flowing out from the overlapping portion to the inner surface of the container. In addition, the apparatus accommodated in a cryostat is installed in a container at this time, and piping, wiring, etc. are connected beforehand.

  After joining the container halves 11a and 11b, as shown in FIG. 6, the prepreg 16 is attached to the outer peripheral surfaces of the tapered surfaces 12a and 12b, and the outer peripheral surface of the laminated prepreg 16 is the container half 11a, Lamination is performed so as to be substantially flush with the outer peripheral surface of 11b (prepreg lamination step). The prepreg 16 is usually preferably attached by winding a tape-shaped prepreg, but in the same manner as the above-described member manufacturing process, the prepreg 16 is generally applied according to the state of the prepreg 16 and the state of the attaching portion. The FRP molding procedure can be performed.

  After the prepreg 16 is laminated in a predetermined state, as shown in FIG. 7, the portion where the prepreg 16 is laminated is covered with an airtight sheet 17 to be in a sealed state, and the exhaust pipe 18 is connected to the airtight sheet 17. At this time, if necessary, a seal material 19 or an adhesive tape is used. As shown in FIG. 8, a vacuum pump 21 is connected to the exhaust pipe 18 to perform evacuation, and a portion covered with an airtight sheet 17 is necessary. Check for sufficient airtightness.

  Next, as shown in FIG. 9, evacuation of the portion where the prepreg 16 is laminated by the vacuum pump 21 is started through the exhaust pipe 18 which is put into the autoclave 20 and pulled out to the outside, and the inside of the autoclave 20 is brought to a predetermined temperature. While heating, pressurize to a predetermined pressure. Further, pressure is applied from the inside using the pipe 15 or the like (prepreg curing step).

  As shown in FIG. 10, when the prepreg 16 is sufficiently deaerated, the airtight sheet 17 comes into close contact with the outer peripheral surface of the prepreg 16, and is pressed by the pressure from the outside and the pressure from the inside. The prepreg 16 is strongly pressed against the outer peripheral surface of the container, so that the tapered surfaces 12a and 12b and the prepreg 16 are in a more intimate contact state. At the same time, the prepreg 16 is cured by being heated to a predetermined temperature, and the concave portions of the tapered surfaces 12a and 12b are covered with the same FRP 16a as the portions where the tapered surfaces 12a and 12b of the container halves 11a and 11b are not formed. It becomes a state.

  When the evacuation and pressurization are finished and the heating is finished and the sheet is taken out from the autoclave 20 and the airtight sheet 17 is removed after cooling, as shown in the partial sectional front view of FIG. An FRP cryostat 22 in the form of a sealed container in which 15 or the like is arranged is obtained. Since the outer periphery of the joint portions of the container halves 11a and 11b in the FRP cryostat 22 is covered with the FRP 16a obtained by curing the prepreg 16 laminated on the outer peripheral surfaces of the tapered surfaces 12a and 12b as described above, the taper processing is performed. Similar to the container halves 11a and 11b in the portions where the process is not performed, the structure is reinforced with glass fibers that are overlapped several times. Therefore, compared with the joint part in the conventional FRP cryostat, the strength against mechanical shock and thermal shock is high, there is no occurrence of resin peeling and cracking, and almost no vacuum leak occurs.

  Therefore, the FRP cryostat 22 manufactured in this way has an adhesive surface that does not exist on the outer surface of the cryostat, and the joint and its periphery are covered with multiple glass fibers, so that liquid nitrogen, liquid helium, etc. The structure is resistant to stress-strain caused by repeated cooling with a low-temperature liquid. Conventional FRP cryostats are generally used in a static field without vibrations or impacts. However, the FRP cryostats 22 manufactured by the method of the present invention are not subject to vibrations or vibrations. It can be used even in a typical place.

  In addition, the division | segmentation number of the member made from FRP can be arbitrarily set according to the shape and magnitude | size of the cryostat to manufacture. Further, the angle of the tapered surface can be arbitrarily set in consideration of the size and thickness of each member, and when the FRP member is manufactured, the tapered surface or the superposed piece may be formed. Further, the appearance of the cryostat can be improved by making the FRP formed on the outer circumferences of the tapered surfaces 12a and 12b flush with other portions, but there may be some unevenness.

It is a cross-sectional front view of the FRP container half produced as an FRP member. It is a cross-sectional front view which shows the state which formed the taper surface and the superposition | polymerization piece in the container half body made from one FRP used as a container lower half part. It is a cross-sectional front view which shows the state which formed the taper surface and the superposition | polymerization piece in the other FRP container half used as the container upper half part. It is a cross-sectional front view which shows the state which adhered piping etc. to the other container half made from FRP. It is a cross-sectional front view which shows a state when opening and joining the opening of a container half made of FRP. It is a cross-sectional front view which shows the state which laminated | stacked the prepreg on the outer peripheral surface of the taper surface. It is a cross-sectional front view which shows the state which covered the part which laminated | stacked the prepreg with the airtight sheet | seat. It is a cross-sectional front view which shows the state which has confirmed the airtightness of the part covered with the airtight sheet | seat. It is a cross-sectional front view which shows the state which started the hardening of a prepreg by heating and pressurizing within an autoclave. It is a sectional front view showing the state where hardening of a prepreg in an autoclave was completed. It is a partial cross section front view which shows one example of the obtained cryostat made from FRP.

Explanation of symbols

  11, 11a, 11b ... FRP container half, 12a, 12b ... tapered surface, 13a, 13b ... polymerized piece, 14 ... through hole, 15 ... piping, 16 ... prepreg, 17 ... airtight sheet, 18 ... exhaust pipe, 19 ... Sealing material, 20 ... Autoclave, 21 ... Vacuum pump, 22 ... Cryostat made of FRP

Claims (7)

  In a manufacturing method of a sealed container-shaped FRP cryostat that contains a low-temperature fluid, when the cryostat is formed by joining a plurality of FRP members, each FRP member is manufactured in a preset shape. A taper forming step of forming a tapered surface in which the outer surface portion of the FRP member manufactured in the member manufacturing step and the other FRP member in the vicinity of the bonded portion is thinned toward the bonded portion. Polymerization piece forming step of forming a piece of polymerized piece protruding from the end face of one FRP member at the inner position and from the end face of the other FRP member at the outer position, respectively. And the polymerized surface portion of the polymerized piece of the FRP member on which the tapered surface and the polymerized piece are formed are polymerized inward and outward directions, A member joining step for joining the joined portions of each other, a prepreg laminating step for pasting and laminating prepregs on the tapered surfaces of both joined FRP members, and a prepreg curing step for degassing and curing the laminated prepregs A method of manufacturing a cryostat made of FRP, comprising:   The method for producing an FRP cryostat according to claim 1, wherein in the member joining step, a polymerized surface portion of the polymerized piece is polymerized through an adhesive.   The method for manufacturing an FRP cryostat according to claim 1, wherein the FRP members are an upper half and a lower half of the cylindrical container.   4. The method for manufacturing an FRP cryostat according to claim 3, wherein, in the member joining step, the polymerized piece is polymerized so that the polymerized piece of the FRP member that is the upper side of the container when in use is positioned outside.   The method for producing an FRP cryostat according to claim 3, wherein, in the prepreg curing step, the prepreg laminated portion outside the container is evacuated and the inside of the container is pressurized.   The method for manufacturing an FRP cryostat according to claim 1, wherein an airtight test is performed after the bonded portions of the FRP members are primarily bonded together in the member bonding step.   A FRP cryostat manufactured by the manufacturing method according to claim 1.

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