JP2000002389A - Joint and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint, which is easily workable and provided with stable quality and economical heat insulation, by forming a heat insulating layer between an inner circumference part and an outer circumference part formed of thermoplastic synthetic resin and integrally molding the inner circumference part and the outer circumference part. SOLUTION: In a joint 1 formed of thermoplastic synthetic resin such as hard vinyl chloride resin, a heat insulating layer 14 is formed between an inner circumference part 12 and an outer circumference part 13. Sockets 11 for a pipe are arranged on both sides of the joint 1. The inner circumference part 12 and the outer circumference part 13 of the joint 1 are integrally molded. In this way, the heat insulating layer 14 is formed between the inner circumference part 12 and the outer circumference part 13 formed of thermoplastic synthetic resin, so that post-installation of a heat insulating material is not required, and installation can be facilitated. As the inner circumference part 12 and the outer circumference part 13 are integrally molded, quality can be stabilized while man-hours for assembly and the like is dispensable economically. In addition, exposure of the heat insulating layer 14 is prevented when a gate is cut, and an appearance is not deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a heat insulating material is provided on the outer periphery of a pipe and a pipe joint for preventing dew condensation, heat insulation and sound insulation. Heat insulation and heat insulation of the pipe joint are usually performed by wrapping a heat insulating material around the outer periphery of the joint after piping, or attaching a heat insulating cylinder divided into two parts to the outer periphery of the joint. Further, an integral joint in which a heat insulating material is integrally assembled on the outer periphery of the joint is also known.

[0003]

However, the method of winding a heat insulating material around the outer periphery of the joint after the piping or attaching the heat insulating cylinder divided into two parts to the outer periphery of the joint has a problem that it takes time and labor to construct the joint. In addition, an integrated joint in which a heat insulating material is integrally assembled on the outer periphery of the joint has a problem that quality variation is sufficient at the time of assembling, and the assembling is troublesome, resulting in an increase in cost.

[0004] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to facilitate the construction,
An object of the present invention is to provide a joint having stable quality and economical heat insulating properties, and a method for manufacturing the same.

[0005]

According to a first aspect of the present invention, there is provided a joint in which a heat insulating layer is formed between an inner peripheral portion and an outer peripheral portion formed of a thermoplastic synthetic resin. And an outer peripheral portion are integrally formed.

According to a second aspect of the present invention, there is provided the joint manufacturing method according to the first aspect, wherein the joint manufacturing apparatus includes an injection mold and first and second injection molding machines. (1)
A first step of injecting and injecting the melted thermoplastic synthetic resin into the mold from a first injection molding machine; and (2) stopping the first injection molding machine and then moving the mold from the second injection molding machine to the mold. (2) a second step of injecting a foamable liquid synthetic resin into the mold and injecting it so as to fill a water pool provided in the weld portion;
Next, the second injection molding machine is stopped, and the molten thermoplastic synthetic resin is again injected and injected from the first injection molding machine into the mold, and the injected thermoplastic synthetic resin is used to fill the mold with an injection port (gate). And (4) finally, a fourth step of taking out the molded joint by opening the mold after cooling and solidifying the injected synthetic resin by cooling.

According to a third aspect of the present invention, there is provided the joint manufacturing method according to the first aspect, wherein the joint manufacturing apparatus includes an injection mold, a first and a second injection molding machine, A gas inlet provided at an outlet of the injection molding machine, and a basin provided with a gas release mechanism at a weld portion of the injection molding die. (1) From the first injection molding machine to the mold, A first step of injecting and injecting the molten thermoplastic synthetic resin,
(2) After that, a second step of injecting a compressed gas from a gas inlet to form a hollow layer filled with the compressed gas inside the injected thermoplastic synthetic resin, and (3) being provided in the weld portion A third step of degassing the hollow layer filled with the compressed gas by the degassing mechanism, and then injecting and injecting a foamable liquid synthetic resin into the mold from a second injection molding machine; And (4) finally, a fourth step of opening the mold and removing the molded joint after cooling and solidifying the injected synthetic resin.

(Function) In the joint according to the first aspect, since the heat insulating layer is formed between the inner peripheral portion and the outer peripheral portion formed of the thermoplastic synthetic resin, it is not necessary to retrofit the heat insulating material and the construction is possible. It will be easier. In addition, since the inner peripheral portion and the outer peripheral portion are integrally formed, the quality is stable, and the man-hour for assembling and the like are not required, so that it is economical.

According to a second aspect of the present invention, in the first step of injecting and injecting a thermoplastic synthetic resin,
While the resin in contact with the wall surface of the mold forms a solidified layer, the middle portion not in contact with the wall surface maintains the fluidized bed and is injected while being pressed one after another. Then, in the second step of injecting and injecting the foamable liquid synthetic resin, the foamable liquid synthetic resin is injected while foaming into the fluidized bed of the thermoplastic synthetic resin solidified on the wall surface of the mold. Then, the resin injected at the weld portion merges from both sides. Then, a thermoplastic resin and a foamable synthetic resin are filled in a water pool provided in the weld portion. As a result, the inner peripheral portion and the outer peripheral portion of the joint are formed of the thermoplastic synthetic resin solidified on the wall surface of the mold, and the heat insulating layer is formed of the synthetic resin foamed between the inner peripheral portion and the outer peripheral portion. You. Therefore, the joint in which the heat insulating layer is formed between the inner peripheral portion and the outer peripheral portion can be formed by one-shot molding, which is economical. In addition, since the vicinity of the injection port (gate) of the mold is closed with the thermoplastic synthetic resin injected in the third step, the heat insulating layer is not exposed when the gate is cut. Therefore, appearance defects cannot be caused.

According to a third aspect of the present invention, in the first step of injecting and injecting a thermoplastic synthetic resin,
While the resin in contact with the wall surface of the mold forms a solidified layer, the middle portion not in contact with the wall surface maintains the fluidized bed and is injected while being pressed one after another. Then, in the second step, a hollow layer filled with a compressed gas is formed inside the injected thermoplastic synthetic resin, and in the third step, after the hollow layer filled with the compressed gas is degassed, Since the foamable liquid synthetic resin is injected and injected into the mold from the second injection molding machine, the hollow layer is filled with the synthetic resin foamed at a high magnification. As a result, the inner peripheral portion and the outer peripheral portion of the joint are formed of the thermoplastic synthetic resin solidified on the wall surface of the mold, and the heat insulating layer is formed of the synthetic resin foamed at a high magnification between the inner peripheral portion and the outer peripheral portion. Is formed. Therefore,
The joint with the heat insulating layer can be formed by one shot, so that it is economical. Further, since the synthetic resin of the heat insulating layer can be made to have a high expansion ratio, the heat insulating property is excellent.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. FIG. 1 is an explanatory diagram of a joint, and FIG. 2 is an explanatory diagram showing a method of manufacturing the joint of FIG. In FIG. 1, reference numeral 1 denotes a joint, and the joint 1 is formed of a thermoplastic synthetic resin such as a hard vinyl chloride resin, and has an inner peripheral portion 12 and an outer peripheral portion 1.
3, a heat insulating layer 14 is formed. On both sides of the joint 1, there are provided insertion ports 11, 11 for pipes. The inner peripheral portion 12 and the outer peripheral portion 13 of the joint 1 are integrally formed.

A method for manufacturing the joint 1 will be described with reference to FIG. In FIG. 2, reference numeral 2 denotes a manufacturing apparatus for the joint 1, and the manufacturing apparatus 2 includes an injection molding die 3, a screw-type first injection molding machine 4, and a second injection molding machine 5. A nozzle 45 is provided at an outlet of the first and second injection molding machines 4 and 5, and a pool 32 is provided at a weld portion 31 which joins from both sides of the annular cavity 30 of the injection molding die 3. I have.

The joint 1 is manufactured by the following steps using the manufacturing apparatus 2 described above. (1) In the first step, a thermoplastic synthetic resin P1 such as a hard vinyl chloride resin is supplied to the first injection molding machine 4, which is heated and melted, and the gate 33 (injection port) of the mold 3 is supplied from the nozzle 45.
Inject the thermoplastic synthetic resin P1 melted through
Inject into cavity 30.

(2) In the second step, thereafter, the first injection molding machine 4 is stopped, and a thermoplastic synthetic resin P2 mixed with a foaming agent is supplied from the second injection molding machine 5 to the mold 3; This is melted and injected, and injected so as to fill the pool 32 provided in the weld portion 31. FIG. 2 shows the progress of the second step.

(3) Next, in the third step, the second injection molding machine 5 is stopped, and the molten thermoplastic synthetic resin P1 is again injected from the first injection molding machine 4 into the mold 3 and injected. The vicinity of the gate 33 of the mold 3 is closed with the injected thermoplastic synthetic resin P1. (4) Finally, in the fourth step, after cooling and solidifying the injected synthetic resin P1 and P2, the mold is opened and the formed joint 1 is taken out and finished.

The joint 1 of the present embodiment comprises a heat insulating layer 1 between an inner peripheral portion 12 and an outer peripheral portion 13 formed of a thermoplastic synthetic resin.
Since the number 4 is formed, it is not necessary to retrofit the heat insulating material and the construction is easy. Further, the inner peripheral portion 12 and the outer peripheral portion 13
Is integrally molded, so the quality is stable,
Man-hours for assembly and the like are unnecessary and economical.

Further, according to the manufacturing method of the joint 1 of the present embodiment, in the first step of injecting and injecting the thermoplastic synthetic resin P1, while the resin P1 in contact with the wall surface of the mold 3 forms a solidified layer, The intermediate portion not in contact with the wall surface maintains the fluidized bed and is injected while being pushed one after another. In the second step of injecting and injecting the foamable molten synthetic resin P2, the foamable molten synthetic resin P2 foams in the fluidized bed of the thermoplastic synthetic resin P1 solidified on the wall surface of the mold 3. (See FIG. 2), and the resin P1, P2 injected in the weld portion 31.
Merge from both sides. Then, the water pool 32 provided in the weld portion 31 is filled with the thermoplastic synthetic resin P1 and the foamable synthetic resin P2. As a result, the inner peripheral portion 1 of the joint 1 is made of the thermoplastic synthetic resin P1 solidified on the wall surface of the mold 3.
2 and an outer peripheral portion 13 are formed, and an inner peripheral portion 12 and an outer peripheral portion 13 are formed.
The heat insulating layer 14 is formed of the synthetic resin P2 that has been foamed in between. Therefore, the joint 1 in which the heat insulating layer 14 is formed between the inner peripheral portion 12 and the outer peripheral portion 13 can be molded by one-shot molding, which is economical. In addition, since the vicinity of the injection port 33 (gate) of the mold 3 is blocked by the thermoplastic synthetic resin P1 injected in the third step, the heat insulating layer 14 is not exposed when the gate 33 is cut. Therefore, appearance defects cannot be caused.

FIG. 3 shows another embodiment of the present invention, and is an explanatory view showing a method of manufacturing the joint 1. As shown in FIG. In the present embodiment, the same components as those in the previous embodiment are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 3, reference numeral 2A denotes a manufacturing device of the joint 1, and the manufacturing device 2A includes an injection molding die 3, a screw-type first injection molding machine 4 and a second injection molding machine 5. A nozzle 45 having a gas injection port 6 is provided at the outlet of the first and second injection molding machines 4 and 5, and a weld portion 3 which joins from both sides of the annular cavity 30 of the injection mold 3.
1, a water pool 32 provided with a gas release mechanism 34 is provided.

Using the above-described manufacturing apparatus 2A, the joint 1 is manufactured in the following steps. (1) In the first step, the molten thermoplastic synthetic resin P1 is injected from the first injection molding machine 4 into the mold 3 and injected. (2) Thereafter, in the second step, the compressed gas G is injected from the gas injection port 6 to form a hollow layer filled with the compressed gas G inside the injected thermoplastic synthetic resin P1.

(3) In the third step, the gas in the hollow layer filled with the compressed gas G is released by the gas release mechanism 34 (the compressed gas G is released by inserting a needle-like member) provided in the weld portion 31. After punching, the second injection molding machine 5
Then, foamable synthetic resin P2 is injected into mold 3 and injected. (4) Finally, after cooling and solidifying the injected synthetic resins P1 and P2, the mold is opened and the molded joint 1 is taken out.
Finish processing.

According to the method of manufacturing the joint 1 of the present embodiment,
In the first step of injecting and injecting the thermoplastic synthetic resin P1,
While the resin P1 in contact with the wall surface of the mold 3 forms a solidified layer, an intermediate portion not in contact with the wall surface maintains the fluidized bed and is injected while being pressed one after another. Then, in the second step, a hollow layer filled with the compressed gas G is formed inside the injected thermoplastic synthetic resin P1, and in the third step, the hollow layer filled with the compressed gas G is degassed. After that, the second injection molding machine 5
From above, the foamable liquid synthetic resin P2 is injected and injected into the mold 3, so that the synthetic resin P2 in which the hollow layer is foamed at a high magnification.
Filled with. As a result, the inner peripheral portion 12 and the outer peripheral portion 13 of the joint 1 are formed of the thermoplastic synthetic resin P1 solidified on the wall surface portion of the mold 3, and a high magnification is provided between the inner peripheral portion 12 and the outer peripheral portion 13. The heat insulating layer 14 is formed of the foamed synthetic resin P2. Therefore, the joint 1 on which the heat insulating layer 14 is formed can be formed by one shot, so that it is economical, and the synthetic resin P2 of the heat insulating layer 14 can have a high expansion ratio, so that the heat insulating property is excellent.

[0021]

According to the joint of the first aspect, since the heat insulating layer is formed between the inner peripheral portion and the outer peripheral portion formed of the thermoplastic synthetic resin, it is not necessary to retrofit the heat insulating material and the installation is easy. Becomes In addition, since the inner peripheral portion and the outer peripheral portion are integrally formed, the quality is stable, and the man-hour for assembling and the like are not required, so that it is economical.

According to the method for manufacturing a joint according to the second aspect, a joint in which a heat insulating layer is formed between an inner peripheral portion and an outer peripheral portion can be formed by one-shot molding, which is economical. Further, since the heat insulating layer is not exposed when the gate is cut, there is no problem in appearance.

According to the method for manufacturing a joint according to the third aspect, the joint on which the heat insulating layer is formed can be formed in one shot.
It is economical and has excellent heat insulating properties because the synthetic resin of the heat insulating layer can have a high expansion ratio.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a joint according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a method of manufacturing the joint shown in FIG. 1;

FIG. 3 is an explanatory view showing a method of manufacturing a joint according to another embodiment of the present invention.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Joint 12 Inner peripheral part 13 Outer peripheral part 14 Heat insulation layer 2 Manufacturing apparatus 3 Die 31 Weld part 32 Hot water pool 33 Injection (gate) 34 Degassing mechanism 4 First injection molding machine 5 Second injection molding machine 6 Gas injection port P1 Thermoplastic synthetic resin P2 Foamable synthetic resin G Compressed gas

Claims (3)

[Claims] 1. A joint in which a heat insulating layer is formed between an inner peripheral portion and an outer peripheral portion formed of a thermoplastic synthetic resin, wherein the inner peripheral portion and the outer peripheral portion are integrally formed. Fitting. 2. A manufacturing apparatus for a joint, comprising: an injection mold; and first and second injection molding machines, wherein a pool is provided at a weld portion of the injection mold. A first step of injecting and injecting the melted thermoplastic synthetic resin from the injection molding machine into the mold; and (2) then stopping the first injection molding machine and foaming the second injection molding machine into the mold. A second step of injecting a liquid synthetic resin having a property and injecting so as to fill a water pool provided in a weld portion; and (3) stopping the second injection molding machine, and A third step of injecting and injecting the molten thermoplastic synthetic resin into the mold again, and closing the vicinity of the injection port (gate) of the mold with the injected thermoplastic synthetic resin; and (4) finally, injection and injection The fourth step of opening the mold and removing the molded joint after cooling and solidifying the synthetic resin The process according to claim 1, wherein the joint, characterized in that it consists of. 3. An apparatus for manufacturing a joint, comprising: an injection mold; first and second injection machines; and a gas inlet provided at an outlet of the injection machine. A water pool provided with a degassing mechanism at a weld portion of the mold; (1) a first step of injecting and injecting a molten thermoplastic synthetic resin into the mold from a first injection molding machine; (2) Then, a second step of injecting a compressed gas from a gas inlet to form a hollow layer filled with the compressed gas inside the injected thermoplastic synthetic resin, and (3) degassing provided in the weld portion A third step of injecting and injecting a foamable liquid synthetic resin from the second injection molding machine into the mold after degassing the hollow layer filled with the compressed gas by a mechanism; (4) finally After the injection injected synthetic resin is cooled and solidified, the mold is opened and molded. Fourth step and process according to claim 1, wherein the joint, characterized in that it consists of taking out the joint.