JPH0547699U - Joint structure of plastic containers - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] Excellent connection strength and seal between the container body and lid.
(EN) Provided is a joint structure of a plastic container which can be easily joined. [Structure] A convex portion 11 or a concave portion 21 is provided along the outer circumference of one end of a plastic container piece 1 to be joined to each other, and a concave portion 21 or a convex portion 11 is provided along the inner circumference of the end portion of the other container piece 2, and both end portions are It is characterized in that the convex portion 11 and the concave portion 21 are connected to each other by a meshing without a gap, and the outer surfaces of both end portions are welded.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a joint structure for a plastic container used for assembling a pressure-resistant plastic container such as a filter housing.

[0002]

[Prior Art]

 In a container of equipment used for treating high-pressure fluid, for example, a filter container, a lid body must be joined to the container body with a predetermined connection strength and sealability according to the fluid pressure.

Conventionally, as a joining structure of such a container body and a lid body, as shown in FIG. 3A, a structure in which a lid body 2 ′ is welded to a container body 1 ′ (3 ′ indicates a welded portion). ), As shown in FIG. 3B, a structure in which the lid body 2 ′ is screwed to the container body 1 ′ through the packing 3 ″ (4 ′ indicates a screwed portion) and FIG. As shown in (), a structure is known in which a lid body 2'is screwed to a container body 1 ', and the two are welded together (5' indicates a welded portion).

[0004]

[Problems to be solved by the device]

 However, in the joint structure shown in Fig. 3 (a), the reliability of the mechanical strength of plastic welding is low due to the fact that the polymer is easily decomposed during welding. Is significant, so there is a problem.

Further, in the joint structure shown in FIG. 3B, the connection strength against the internal pressure can be guaranteed by the screw connection, but under high temperature use, the O-ring and the container itself are softened, so that the sealing surface of the O-ring is softened. There is a problem in terms of sealability because the pressure must be reduced. Regarding this sealing property, it is necessary to process the sealing surface in order to eliminate deterioration of the sealing property due to surface roughness of the O-ring sealing surface and minute scratches on the sealing surface, which is troublesome. is there.

Further, in the joint structure shown in FIG. 3C, due to the backlash between the male thread groove and the female thread groove of the threaded portion, the tension corresponding to the gap dimension of the backlash is generated under the action of the internal pressure. Strain acts on the weld and unavoidable tensile stress. Therefore, the welded surface of the plastic is molecularly integrated, and if the stress can be eliminated, a sufficient sealability can be expected. In the welded portion of the joint structure shown, the action of tensile stress is unavoidable, so there is a problem with the sealability.

An object of the present invention is to provide a joining structure for a plastic container that can easily join the container body and the lid with excellent connection strength and sealability.

[0008]

[Means for Solving the Problems]

 The plastic container joining structure of the present invention has a convex portion or a concave portion along the outer circumference of one end of the plastic container pieces to be joined to each other, and a concave portion or a convex portion along the inner circumference of the end of the other plastic container piece. Is connected by a meshing between the convex portion and the concave portion without a gap, and the outer surfaces of both end portions are welded.

[0009]

[Action]

 Engagement of the concavo-convex portion can guarantee sufficient connection strength against the internal pressure of the container. Further, since the concavo-convex meshing portion supports the internal pressure of the container, it is possible to eliminate the tensile stress acting on the welded portion, and the welded portion effectively exhibits the sealing action.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 is a plastic container body, and a convex portion 11 is formed along the outer periphery of the upper end. Reference numeral 2 denotes a lid, which is provided with a concave portion 21 along the inner circumference of the lower end portion, and a convex portion 22 is present below and adjacent to the concave portion 21.

The upper end portion of the container body 1 and the lower end portion of the lid body 2 are connected by a toothless engagement between the concave portion 21 and the convex portion 11, and the outer peripheral surface of the convex portion 11 and the concave portion 21 are connected. A constant surface pressure is applied between the inner peripheral surface, the upper side surface of the convex portion 11 and the upper side surface of the concave portion 21, and the lower side surface of the convex portion 11 and the lower side surface of the concave portion 21. .

To connect the upper end of the container body and the lower end of the lid body, the lid body 2 is heated to expand and the container body 1 is contracted by cooling so that the inner diameter of the lower end portion of the lid body 2 becomes the upper end of the container body 1. It is possible to use a method in which the outer diameter of the convex portion 11 is made larger, the upper end of the container body is inserted into the lower end of the lid, and then both 1 and 2 are returned to room temperature. In particular, when the meshing allowance (the height of the convex portion 11 or the depth of the concave portion 21) is large, the inner diameter of the lower end portion of the heated lid body 2 is set within the elastic deformation region by a cylindrical expanding jig. It is desirable to expand the diameter, insert the upper end of the container body 1 into the lid body 2 through this expansion jig, and then remove the expansion jig.

In FIG. 1, reference numeral 3 denotes a welded portion between the container body 1 and the lid body 2, in which a lower end surface 23 of the lid body 2 and an outer surface of the container body 1 are welded by a ring-shaped plastic welding material 30. is there.

In the above-mentioned plastic container, oop stress and longitudinal tensile stress act on the container wall due to the fluid pressure in the container, and the oop stress of the container body 1 is measured according to a conventional method. This can be dealt with by setting the thickness and the thickness of the lid body 2 to predetermined dimensions.

On the other hand, based on the tensile stress in the lengthwise direction, a surface pressure acts on the locking surface a between the lower surface of the convex portion and the lower side surface of the concave portion in the concave and convex engaging portion, and the convex portion is formed on the container body 1. The maximum shear stress acts along the root indicated by the dotted line m of 11, and the maximum shear stress acts on the lid 2 along the root indicated by the dotted line n of the convex portion 22 at the lower end of the inner circumference. By making the width of the roots thick enough, the shear strain can be suppressed well, and substantially all of the container internal pressure can be supported by the concave and convex meshing parts, and the tensile stress on the weld 3 due to the container internal pressure The action can be eliminated.

Therefore, it is possible to stably maintain the integration of the intermolecular bonds on the welded surface of the welded portion 3, and even if the fluid in the container cannot be sealed only by the contact surface of the uneven meshing portion, Excellent sealability can be guaranteed by complementing the stable molecular bonding surface.

FIG. 2 is a partial sectional view showing another embodiment of the present invention. In this embodiment, a concave portion 21 is provided along the outer circumference of the upper end portion of the container body 1, and a convex portion 11 is provided along the inner circumference of the lower end portion of the lid body 2. The lower end surface of the lid body 2 and the outer peripheral surface of the container body 1 are welded 3 from 30 to a plastic welding material by connecting them.

Also in this embodiment, substantially all of the container internal pressure can be supported only by the concave and convex meshing portions, the action of tensile stress on the welded part due to the container internal pressure can be eliminated, and the welded surface at the welded part can be eliminated. It is possible to maintain stable bond integration between the molecules of the container, and even if the fluid in the container cannot be sealed only with the contact surface of the concave-convex meshing portion, it is an excellent seal because of the stable molecular bond surface of the welding surface. Security can be guaranteed

[0019]

[Effect of the device]

 The joint structure of the plastic container of the present invention has the structure as described above, the connection strength against the internal pressure of the container can be assured by the concavo-convex engagement portion, and the sealing property for the fluid in the container can be complemented by the welded portion. Regarding the meshing of uneven parts, plastic has a larger coefficient of thermal expansion and a smaller Young's modulus than metal, so it is easier than shrink-fitting of metal members, and welding has almost no mechanical strength. It's not required and can be done easily. Therefore, according to the present invention, a plastic container having excellent mechanical strength and sealability can be easily assembled.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention.

FIG. 2 is a partial sectional view showing another embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing different conventional examples.

[Explanation of symbols]

 1 Container Piece 11 Convex Part 2 Container Piece 21 Recessed Part 3 Welded Part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Makoto Himeno Makoto Himeno 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Takashi Yamagishi 3304-1, Yakushiji Temple, Minamikawachi Town, Kawachi District, Tochigi Prefecture

Claims (1)

[Scope of utility model registration request] 1. A plastic container piece to be joined to each other is provided with a convex portion or a concave portion along the outer circumference of one end portion, and a concave portion or a convex portion is provided along the inner circumference of the end portion of the other container piece, and both end portions are a convex portion and a concave portion. A joint structure for a plastic container, characterized in that the outer surfaces of both ends are welded together by a meshing with no gap between them.