JPH091567A - Flange joint simultaneously forming method for thermoplastic resin vessel - Google Patents

Abstract

PURPOSE: To form an outlet having a flange joint simultaneously with the rotary molding of a vessel in the state that the join is not formed in a cavity when a hollow vessel is manufactured by a rotary molding method. CONSTITUTION: A ring-like article 18 to become a flange joint is manufactured by a thermolastic resin capable of fusion bonding to the thermoplastic resin for manufacturing a vessel. The article 18 is held at the same position as the joint with respect to the body mold 13 while surrounding and pressing by molds 14, 15 for molding an outlet 3. The molds 14, 15 are coupled to the mold 13 and to communicate with the body mold. A rotary molding is conducted in this state to form the outlet 3 having the joint.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to polycarbonate,
For forming a flange joint of the outlet at the same time when a container for storing a fluid such as liquid, powder or granule is manufactured by a rotational molding method using a thermoplastic resin such as PFA, polyethylene or ethylene tetrafluoride. To use.

[0002]

2. Description of the Related Art For storing liquids such as liquids and powders,
A large container 1 made of resin as shown in FIG. 6 (side view) is used. In FIG. 6, 2 is an inlet for the contents (a lid is not shown), 3 is an outlet, and a flange joint 4 is provided so that a flange joint of another pipe or valve can be connected. Such a large container 1 is made of a thermoplastic resin by a rotational molding method. In this conventional rotational molding method, the mold is heated while rotating the main mold, which is a split mold for molding the main body 1a of the container 1, around two axes orthogonal to each other, and the inside of the mold is preliminarily heated. Melt the thermoplastic resin powder put in and flow along the inner surface of the mold to form the container wall,
After cooling the mold, the solidified molded product is taken out from the mold to obtain a finished product.

When molding the main body 1a of the container 1 by the rotational molding method, at the same time, it is difficult to form the outlet 3 having the defect-free flange joint 4 as described later. Therefore, conventionally, the outlet has been formed as shown in FIG. 7 (enlarged sectional view taken along the line AA in FIG. 6).
That is, a screw cylinder 6 having a hole formed in the main body 1a of the container 1 and having a flange 5 in the hole 1b and having threads formed on the inner and outer surfaces is inserted from the inside of the main body with a packing 7 sandwiched between the flange 5 and the main body 1a. To do. A nut 8 and a lock nut 9 are tightened to the screw cylinder 6 outside the main body to press the packing 7, the screw cylinder 6 is liquid-tightly connected to the main body 1a, and the take-out pipe 12 is connected thereto. The take-out pipe 12 is one in which a screw is formed on the outer surface of the inner end portion, a flange 11 is formed at the middle portion, and a flange 4 is formed at the outer end portion. The inner end portion is screwed into the screw cylinder 6 to The packing 10 is pressed against the end surface of the screw cylinder 6 to couple the take-out pipe 12 to the screw cylinder 6 in a liquid-tight manner. This take-out pipe 12
Serves as an outlet 3 for the contents.

[0004]

Forming the outlet in this manner is not preferable because the structure is complicated and the number of parts and the number of working steps are large.

Avoiding such a complicated structure, the main body 1a
As shown in FIG. 8, the split mold 14 and the flat plate mold 15 are attached to the main mold 13 for making the main body 1a in order to simultaneously form the take-out port 3 having the flange joint 4 during the rotational molding of The fixing means of 14, 15 are the same as those of FIG. 4 described later, but illustration and description thereof are omitted here.) When the resin is rotationally molded, the molten resin covers the inner surface of each mold in layers as shown by the contour line 16. An outlet 3 and a flange joint 4 are formed at the same time as the main body 1a. The end of the blocked outlet 3 is cut open after molding. However, in this way, the flange joint 4
When the take-out port 3 is formed, it is difficult to sufficiently supply the molten resin to the joint 4, so that the cavity 17 is formed as shown in FIGS. 9 and 10. The flange joint in which the cavity is formed has a low withstand pressure, and easily deforms and leaks when it is bolted together with the flange joints of other pipes and valves.

[0006]

The method for simultaneously forming a flange joint of a thermoplastic resin container according to the present invention is a container body (1
A ring-shaped material (18) made of a thermoplastic resin that can be fused with a)
And place it at the position of the flange joint (4) with respect to the main body mold (13) for the main body (1a).
3) Dies (14) (15) for forming outlets that communicate with the inside
Then, this is rotationally molded while being compressed.

[0007]

[Function] Since a ring-shaped object made in advance without a cavity is positioned at the flange joint (4) where the molten resin does not spread during rotation molding and a cavity is likely to occur, the material resin can be supplied to the flange. There is no fear of running out, and the pressure resistance of the flange joint is not weakened. Therefore, the bolt connection between the flange joint (4) and another flange joint can be reliably performed.

Further, since the ring-shaped material (18) is pressed and held by the molds (14) and (15) surrounding it, unevenness due to residual air is formed on the surface of the molded flange joint (4). In addition, since the flange surface is formed along the flat plate mold (15) finished flat, it is possible to ensure the sealing effect by the packing when the flange surface is coupled with other joints such as piping. it can.

[0009]

1 to 5 show an embodiment of the present invention, FIG. 1 is a front view of a preliminarily prepared ring-shaped object, FIG. 2 is a sectional view taken along line BB of FIG. 1, and FIG. 4 is a front view of the take-out port showing a state of being attached to a mold, FIG. 4 is a sectional view taken along the line CC of FIG. 3, and FIG. 5 is a cross-sectional view of the molded take-out port at the same position as in FIG.

The ring-shaped material 18 is made of a thermoplastic resin that can be fused with the main body 1a. For example, the same thermoplastic resin as the main body 1a is formed into a ring shape as shown in FIGS. 1 and 2, and a bolt hole 19 is formed. This ring-shaped object 18 is formed in advance without a cavity, its size is made slightly larger than that of the joint 4, and when sandwiched by the molds 14 and 15, it is pressed by both molds to push out air, Consideration should be given so that no air remains on the surface. The peripheral wall of the center hole of the ring-shaped material 18 is made to project in a mountain shape to improve fusion with the molten resin during rotational molding. Also, when the peripheral wall of the central hole is formed in a cylindrical shape, a recess is formed in the peripheral wall portion, but if the peripheral wall of the central hole is projected in this manner, the recess is not formed. The ring-shaped material 18 is attached to the protrusion 13 a of the main body mold 13 by being sandwiched between the mold 14 that is a split mold and the plate-shaped mold 15. The jig 20 for attaching the molds 14 and 15 to the main body mold 13 is configured such that the arm portion 20a is connected to the bolt 21 that is erected on the main body mold 13 and the U-shaped holding portion 20b.
The molds 14 and 15 are restrained and coupled by a movable pin 22 that fits and slides on a screw, and a bolt 23 screwed to a nut 24 welded to the holding portion, and this is attached to the main mold 13. There is a small gap between the peripheral edge of the mold 15 and the end face of the cylindrical outer wall of the mold 14, and the spring washer 25 fitted to the bolt-shaped movable pin 22 moves as the ring-shaped object 18 gradually melts by heating. The mold 14 is pushed through the pin 22, the gap is shortened and the ring-shaped object 18 is continuously pressed, and a small amount of air remaining on the side surface is pushed out. To prevent a dent from being formed. Reference numeral 26 is a small bolt that is attached to the pin 22 by inserting it laterally so that the movable pin 22 does not fall off from the holding portion 20b of the jig. Further, the flat plate mold 15 has a fixing pin 27 that is closely fitted into the bolt hole 19 of the ring-shaped object 18 and the end portion thereof is closely fitted into the hole provided in the mold 14. (Only one shown) is planted and fitted into the mold 14
While inserting this pin into the bolt hole 19 of 8, the mold 15
3 and 4, the positions of the pins 27 and the bolts 23 are shifted and the jigs 20 are attached to the jig 20, and heating is performed so that air does not remain in the bolt holes 19. . In FIG. 4, the upper movable pin 22 and the bolt 23 are in a state in which the molds 14 and 15 are not yet suppressed, and the lower movable pin 2
2, the bolt 23 shows a state where both dies are pressed and pressed.

In this way, the movable pins 22 and the bolts 23 are used to connect the molds 14 and 15, and the bolts 21 are used to connect them to the main mold 1.
3 and spin-mold the main body 1a, the main body mold 13
The resin melted inside flows along the inner surface of the main body mold 13 and also flows into the molds 14 and 15, and the end portion is closed together with the main body 1a as shown by the contour line 16 in FIG. Outlet 3
Is formed. When the molds 14 and 15 are heated together with the main body mold 13, the ring-shaped material 18 is also melted, but is fused with the molten resin that has flowed in from the main body mold 13 to form a complete flange joint 4. At this time, air does not enter the ring-shaped material to form a cavity. The closed end of the outlet 3 is cut open after the molding is completed. In this way, the outlet 3 having the flange joint 4 as shown in FIG. 5 is formed. Since there is no cavity in this joint 4, the pressure resistance is strong,
The bolt can be securely tightened. Further, the surface of the ring-shaped material 18 which is heated and melted during the rotational molding is pressed and molded by the inner surface of the flat-finished plate-shaped mold 15, so that the surface of the flange joint formed from this is flat. And it fits well with other flange joints,
It will enhance the sealing effect of the packing.

[0012]

EFFECTS OF THE INVENTION (1) Since the flange joint 4 of the outlet can be molded simultaneously with the rotational molding of the container body 1a, the outlet can be formed efficiently.

(2) The ring-shaped material 18 is made without a cavity, and the flange joint 4 formed of this has a large pressure resistance without a cavity and is distorted when it is bolted to another flange. Never.

(3) Since the surface of the flange joint 4 is formed flat, the sealing effect of packing can be enhanced.

(4) It is not necessary to make an outlet by a complicated means as in the past.

[Brief description of the drawings]

FIG. 1 is a front view of a ring-shaped object.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a front view of the take-out port showing a state where the ring-shaped object is attached to the main body mold.

FIG. 4 is a sectional view taken along line CC of FIG. 3;

5 is a cross-sectional view of the molded outlet at the same position as in FIG.

FIG. 6 is a side view of the container.

FIG. 7 is an enlarged cross-sectional view taken along the line AA of FIG. 6 showing a conventional outlet.

FIG. 8 is an enlarged cross-sectional view taken along the line AA of FIG. 6 showing a conventional method of simultaneously molding an outlet having a flange joint during rotational molding.

FIG. 9 is a cross-sectional view schematically showing a cavity forming state of the flange joint thus formed.

FIG. 10 is a front view of this flange.

[Explanation of symbols]

 1 Container 1a Main Body 1b Hole 2 Input Port 3 Ejection Port 4 Flange Joint 5 Flange 6 Screw Tube 7 Packing 8 Nut 9 Lock Nut 10 Packing 11 Flange 12 Ejection Tube 13 Main Body Mold 13a Projection 14, 15 Mold 16 Contour Line 17 Cavity 18 Ring 19 Bolt hole 20 Jig 20a Arm 20b Clamping part 21 Bolt 22 Movable pin 23 Bolt 24 Nut 25 Spring washer 26 Small bolt 27 Fixing pin

Claims (1)

[Claims] 1. An outlet (3) having a flange joint (4) in a main body (1a) of a container manufactured by a rotational molding method.
A method of forming a main body (1
A ring-shaped object (18) formed in advance with a thermoplastic resin of a material that can be fused to a) is connected to a main body mold (13) for molding the main body (1a) of the container and is also in communication with the main mold (13). (14) A resin and a ring-shaped product (1) which are held while being pressed by the (14) and (15) to hold the flange joint (4) at a position where the flange joint (4) should be formed and which form the main body (1a) during rotational molding of the main body (1a)
A method for simultaneously forming a flange joint for a thermoplastic resin container, characterized in that the extraction port (3) having the flange joint (4) is formed by fusing the same with 8).