KR20070004488A - Inner surface plastic-lined fittings and manufacturing method theirof for the use of small and medium diameter metal pipe(s) - Google Patents

Abstract

An inner surface plastic-lined fittings and a manufacturing method thereof for the use of small and medium diameter metal pipes are provided to make a thickness of resin thin such that a size of a connecting pipe becomes smaller and water tight is secured when a resin pipe is welded to a metal pipe, increasing durability. An inner surface plastic-lined fittings for the use of small and medium diameter metal pipes is manufactured by injecting a resin into a metal connecting pipe(100). An adhesive resin is injected into an inner circumference of the metal connecting pipe and an inner resin pipe(110) is injected into an inner surface of the adhesive resin by the adhesive resin to be integrally formed with the metal connecting pipe.

Description

Inner Surface Plastic-lined Fittings and manufacturing Method Theirof for the use of small and Medium Diameter Metal pipe (s)}

1 is a conceptual view of the injection of the flange joint pipe lined with a conventional inner surface resin.

Fig. 2 is a longitudinal sectional view of a conventional threaded pipe lined with resin.

Figure 3 is a longitudinal cross-sectional view showing a state in which a screw pipe lined and fused with resin according to the present invention is also fastened with a composite pipe lined with an inner surface.

Figure 4 is a manufacturing process of the screw pipe according to the present invention.

5 is a longitudinal cross-sectional view of a metal fitting tube which is a semi-finished product used in the manufacture of a fitting tube for screws according to the present invention;

6 is a conceptual diagram of an adhesive resin injection process according to the present invention.

7 is a conceptual diagram of an inner resin injection process according to the present invention.

8 is a conceptual diagram of a pressure fusion furnace for fusion welding screw pipe according to the present invention

9 is another example of a conceptual diagram of the pressurizing process of the welding pipe joint according to the present invention.

Figure 10 is an example of another embodiment of the resin tube fusion spliced according to the present invention (tee joint pipe).

Figure 11 is an example of another embodiment (reducer) fused resin tube according to the present invention.

12 is an example of another embodiment in which the resin tube according to the present invention is fused (socket)

13 is an example of another embodiment in which the resin pipe according to the present invention is fused (compression socket joint pipe)

Figure 14 is another embodiment of the resin tube fusion spliced according to the present invention (compression elbow fitting pipe)

15 is an example of another embodiment in which the resin pipe is fused according to the present invention (compression elbow fitting pipe)

Figure 16 is another embodiment of the resin tube fusion spliced according to the present invention (compression elbow fittings)

Figure 17 is another embodiment of the resin tube fusion spliced according to the present invention (compression tee joint pipe)

18 is an example of another embodiment in which the resin pipe is fused according to the present invention (compression tee joint pipe)

19 is another embodiment of the resin tube fusion spliced according to the present invention (compression tee joint pipe)

Explanation of symbols on the main parts of the drawings

100: metal pipe 101: threaded portion

110: inner resin tube 111: inner resin tube screw portion

120: adhesive resin tube

130: joint pipe with resin lining formed on the inner surface

140: core 150: elastic ring

211, 211 ': Internal insertion mold (for internal resin) 212, 212': Internal insertion mold (for adhesive resin)

213: Dowel 214: Dowel Hole

220: resin injection hole 221: discharge hole

222, 222 ': heating means 223: cooling means

224, 224 ': Thermocouple

230: cover plug 231: end plug

232, 232 ': valve or solenoid valve 233: air line

234: injection hole 235: pressure gauge

236: quick disconnect device 237, 237 ': binding means

240: pressurized fusion furnace 241, 241 ': heating means

242: thermometer 243: shelf

244 container 245 pressure regulating solenoid valve

246: timer 247: safety valve

248: circulation pipe 249: pump

250: insulation 251: insulation

252: heat reflector 253: operation panel

254 indicator light 255 mixing tube

300: fixed bottom

The method of lining with a resin inside the conventional joint pipe is shown in Fig. 1 of the Republic of Korea Patent No. 10-388436 [pipe joint having a synthetic resin liner and its manufacturing method] using both ends of the metal joint pipe as an external mold. It is manufactured by injecting and cooling hermetically sealed molten resin. However, in the case of non-polarity such as polyethylene in the resin, the joint tube has no adhesiveness, so the resin and metal tubes are separated from each other. Of course, the thickness of the thickness of the metal tube to insert it is inevitable to maintain a larger diameter, there was a problem that the overall volume is large.

In particular, there is a problem that there is a gap between the liner and the metal tube, which is in close contact with the long term, and there is a lot of possibility of corrosion.In addition, according to the manufacturing method, the scope of application is applicable only to the joint pipes with medium and large flanges. There was a limit to the application of small pipes using

.

In the manufacturing method of injecting resin and lining the joint pipe, we developed a method of fusion between thermoplastic resins such as polyethylene, which are difficult to bond due to nonpolarity, and metal joint pipes, so that resin lining is only responsible for corrosion resistance, not self-supporting function. It is intended to increase the watertightness and durability by reducing the thickness of the resin lining to make the size of the joint pipe as small as possible, while fusion-integrating the resin and the metal pipe.

In particular, the fusion method is intended to be applied to screw joints and crimp joints which are commonly used in small and medium sized pipes.

The present invention is a manufacturing method of injecting a resin and lining a joint pipe, wherein the resin is a thermoplastic nonpolar resin, that is, a method of improving the adhesiveness with a metal such as polyethylene, polypropylene, 4-methylpentene-1 resin, etc. In other words, the fusion method is applied to a small-diameter joint, but hereinafter omitted, it is called a resin.

However, this fusion method is naturally applicable to not only non-polar thermoplastic resin but also to weak adhesive resin, and belongs to the scope of the present invention.

Since the joint pipe of the small-diameter tube is mainly for screwing and for crimping, these are presented one after another, and the other joints are not beyond the scope of the present invention.

  Threaded elbow fittings are manufactured by casting cast iron or by forging cast steel. In the application of the present invention, the material of the small fitting pipe is negligible so that the difference is negligible.

* In the manufacture of a threaded pipe for welding the resin liner by injecting the resin liner inside, first manufacturing a metal pipe; Inserting a metal joint into an injection mold; Injecting an adhesive resin tube; Removing the injection mold of the adhesive resin and attaching the injection mold for the inner resin pipe; Injecting the inner resin tube; Welding the resin pipe to the metal fitting pipe; Cooling the fitting pipe; The manufacturing process that proceeds to the step of forming a screw in the fitting pipe will be described below taking an elbow fitting pipe for the screw as an example.

1. manufacture of metal fittings; The metal joint pipe 100 is manufactured by a known method such as forging or casting, but in applying the present invention to fusion lining, the coefficient of friction of polyethylene and the like is lower than that of cast iron or cast steel, so that the thickness of the liner is considered. Necessity is not necessary for general water supply purposes, and manufactured with the same inner diameter as before but removes oil or grime on the inner surface and preheats it to a predetermined temperature.

5A is a longitudinal cross-sectional view showing a semi-finished product of a pre-formed elbow fitting tube without forming a lining, and FIG. 5B is a longitudinal cross-sectional view of a semi-finished product of a dedicated elbow fitting for lining therein. There is no problem in the application of the present invention, but FIG. 5B has an advantage in that the fluid flowing through the pipe is more easily sealed at the terminal of the tube to be connected and the adhesion of the lining is increased.

2. Attach fitting pipe to injection mold; The prepared metal fittings are mounted on the lower fixing mold 300 of the injection mold and formed in a shape opposite to the lower fixing type to receive the fitting pipes and cover them with the upper fixing type which is combined with the lower fixing type to be fixed by the binding means 237 'and then the inlet 220. ), The inner insertion molds (212 and 212 ') integrally coupled with the inner portion of the metal fitting tube are advanced so that the dowel holes (214) and the dial hole (214), which are the mold binding means formed at the end of the inner insertion mold, are fitted. The two divided inter-insert molds are integrated and then heated by heating means 222.

3. Injection of adhesive resin tube; The injection of the adhesive resin tube 120 injects the melt-kneaded resin through the injection hole 220 which is integrally attached to the internal insertion mold, and the resin adhesive surface of the internal insertion mold and the metal joint tube is at least 40 degrees and maximum 90 degrees before injection. More preferably, it should be heated to an injection temperature of 50 degrees to 70 degrees.

The heating coils 222 and 222 ', which are heating means, are enclosed in an annular shape and inside the inner fixing mold, the lower fixing type and the upper fixing type, and although not shown, they are provided with temperature control means to maintain a constant temperature. The thermocouples 224 and 224 'are interpolated in the inner, lower and upper fixing molds to know the temperature of the inter-inserting mold and the fixture, and the measured temperature is a reference for the temperature control of the heating means.

However, since the thermocouple embedded in the fixture is not directly in contact with the resin, considering the heat transfer rate and specific heat of the metal fittings, a conversion standard is made for each type of fitting to compare the temperature indication value of the thermocouple with the actual estimated temperature. Make it a standard.

When the resin contact surface of the inner mold and the metal joint reaches the injection temperature, injection is started through the injection hole, and the discharge hole 221 is formed at the highest side of the dowel at the part where the two inter-insert molds face each other so that the gas is well taken out. To ensure that all gases are released.

When injection is started, it is injected at high speed as soon as possible, and when a predetermined amount of resin is injected, the injection pressure is stopped and the injection pressure is maintained for a predetermined time.

4. After the injection is completed, the intermittent mold and the filled adhesive resin are cooled (de-cooled) by using the intermittent mold heating means and the cooling means interpolated in parallel. It is used to retreat from the metal fitting pipe and to remove it, and the fitting pipe including the fixture is conveyed for injecting the inner resin by a moving means not shown.

When the fixture inserting the fitting pipe is aligned and fixed in front of the inner resin pipe injection machine by the conveying means (the device is not shown), the interpolation molds 211 and 211 'integrated with the injection hole are advanced into the fitting pipe and inserted.

5. Injection of inner resin tube; When the inner resin injection mold for the inner resin reaches the injection temperature, the inner resin is injected. The process is the same as the injection procedure of the above-mentioned adhesive resin.

However, in the demoulding cooling performed after a predetermined time after injection, the cooling water is circulated in both the insert and the fixture to cool to a predetermined temperature, and then the insert is removed and the fitting pipe is removed from the fixture.

6. fusion; When the injection of the resin is finished and the joint pipe 130 is removed from the mold is provided with a heating means on the wall is sealed from the outside is sent to the pressure fusion furnace 240 that can control the pressure inside the air pipe (233) Compressed air is introduced through ') and heated to a fusion temperature by means of a heating means 241 using an infrared heater, a heating coil, or combustion heat while maintaining a constant pressure, followed by fusion, and then transported to a cooling chamber using a transfer means.

The pressurized fusion path is provided with a shelf 243 capable of loading a large number of containers 244 containing small joint pipes, thereby fusion of a plurality of small joint pipes by operation of a single fusion path.

The constant pressure is maintained in the air pipe from the unshown compressor outside the pressure fusion chamber after first fitting the pipe into a container and charging it in the pressure fusion furnace or when the pressure of the pressure sensor installed inside the pressure fusion chamber is lower than the set value. When compressed air flows in through the pressure gauge 235, the solenoid valve 232 'cuts off the supply of compressed air and maintains a constant pressure when the pressure is increased. Accordingly, when the air expands and the pressure increases, the pressure regulating valve 245 operated by the signal of the sensor installed in the upper part of the pressure fusion chamber reaches a pressure higher than the upper limit of the set pressure. To maintain a constant pressure.

On the other hand, a mechanical safety valve 247 is installed at one side of the upper part of the pressure fusion path so that when the high pressure of the abnormal situation is formed, it is immediately discharged to the outside so as to prepare for the abnormality of the sensor or the failure of the solenoid valve.

When the internal temperature of the pressure welding chamber reaches the set temperature by the operation of the heating means, the timer 246 operates to inform the elapsed time. The pressure and the elapsed time should be appropriately controlled according to the material and the specification of the fitting pipe.

A pump 249 is installed at the lower portion of the pressure fusion path, and a circulation pipe 248 is connected to the other side of the pump so that one side of the circulation pipe is connected to the lower side of the pressure regulating solenoid valve 245 installed at the top of the pressure fusion path. When the air is operated, the air at the bottom of the pressure fusion furnace is recirculated to the upper part of the pressure fusion furnace, so that the internal temperature becomes uniform.

Compressed air, which is additionally supplied at the start of the welding or during the welding, is also heated by the heating means 241 'after passing through the solenoid valve 232', merged into the circulation pipe in the mixing pipe 255, and then introduced into the upper portion of the pressure welding furnace. B minimize the temperature unevenness in the furnace due to the introduction of additional compressed air.

The heat reflection mirror 252 and the heat insulating material 251, the metal fusion furnace wall 240, the heat insulating material 250 in order to minimize the heat loss in the wall of the pressure welding furnace.

8 is a cross-sectional view of the pressure fusion furnace described above.

The heating temperature of the fusion furnace is heated to a temperature of at least 150 to 300 degrees, preferably heated to a temperature of 190 to 240 degrees and maintained for a predetermined time, and then open the pressure regulating solenoid valve to release the pressure, and then take out the cooling pipe Transfer to yarn (not shown).

Another implementation of the 6 'fusion process; When the pressure fusion furnace of claim 5 is not provided, the joint line 130 lined with resin on the inner surface removed from the injection mold blocks one end with a cover plug 230 and the other end is closed with an end plug 231. Bind with clasp 237.

In the cover plug, an inlet 234 for injecting air is formed at the center thereof, and an air pipe 233 is connected, and a pressure gauge 235 and a shutoff valve 232 are attached to the air pipe, so that the pressure in the fitting pipe 130 can be known. have.

Now, the air is injected into the fitting pipe through the inlet to maintain a constant pressure, and then the valve is closed and the pipe after the quick disconnect socket 236 is disconnected and then transferred to a heating chamber (not shown).

The joint pipe 130 transferred to the heating chamber is heated to a temperature of at least 150 degrees to 300 degrees using the heating means of the above 5, but preferably is heated to a temperature of 190 to 240 degrees and maintained for a predetermined time (not shown) (Not shown).

 7. cooling; Cooling may be carried out by immersing in a cooling water tank containing cooling water or by spraying cooling water in a joint pipe, which is performed within the shortest time possible from the heating process.

8. threading; The cooled joint pipe is transferred to the screw molding machine because the joint pipe welded in the fusion chamber is not attached to the plug, but if not, slowly open the shut-off valve to remove the internal pressure and remove the cover plug and end plug. .

Threading should be done by inserting, drilling, and drilling the pipe into the machine first, and then processing it by known cutting or rolling, but screwing should be done not only on the metal part but also on the inner part of the resin pipe.

When the screw is formed, it is inspected, packaged and shipped, but inserts a water-tight core 140 separately injection-molded in order to seal the terminal part of the pipe to be connected. It consists of a cylindrical inner tube to cover the inner tube and reinforcing ribs to reinforce the inner tube and the elastic ring 150 so that the fluid in the tube is not in contact with the metal part when the connection pipe and the negative connection.

So far, examples of threaded elbow fittings, namely, one joint belonging to a small pipe, have been described. However, the above-described examples of other threaded fittings such as tee fittings, wire fittings, reducer fittings, socket joints, etc. 10 to 12 show an example of applying the welding method, but it is natural that a person skilled in the art can apply the welding method to various joint pipes, and it is natural to belong to the scope of the present invention. something to do.

10 shows an embodiment of a threaded tube for screwing, wherein the inner circumferential surface of the connecting tube contacts the inner tube of the silver watertight core and is watertight again by an elastic ring at the end, and the threaded portion of the connecting tube is connected to the threaded portion 101 of the metal tube. It comes in contact with the screw portion 111 of the inner resin tube and is isolated and sealed three times with the fluid in the tube.

11 and 12 show an embodiment in which a liner is fused to a reducer pipe and a socket pipe for a screw, but the method of watertight is omitted since it is the same as the screw tee for a screw.

However, the above injection mold is manufactured in the elbow fitting, the tee fitting or the cross fitting to make the insertion insert into the metal pipe to facilitate the insertion into the metal pipe, and in the socket fitting, the 45 degree elbow fitting or the reducer fitting, Manufactured in one piece.

In the case of an integral end-insertion die, that is, a reducer joint pipe, the insert is inserted from the wide end of the joint pipe as described above.

* Although the elbow tube for the screw applied to the small pipe is presented in the above, the present invention is also applied to the crimped joint pipe, which is also a joint to be applied to the small pipe, but does not require screw molding and manufactures a metal pipe. The method is different from the screw joint pipe but the other processes are the same, so the above method of fusion of the screw pipe joint is cited as it is. The same applies to other reducer joints, cross joints, return joints and flange joints.

13 shows an embodiment of a crimping socket fitting tube, in which FIG. 13A shows a case in which a crimping portion is fused with a liner at a joint of an elastic packing, and a connecting tube is inserted to a liner portion and a resin portion of the connecting tube is It is watertight in close contact with the resin of.

13B is a case where the crimping portion is composed of a circular metal ring and a circular elastic packing, and FIG. 13C is a case where the crimping portion is composed of a rectangular metal ring and a circular elastic packing.

The connection pipe is inserted to the end of the liner and is tightly sealed.

14, 15, and 16 show an example in which a liner is fused according to the type of crimp in the crimp elbow tube, and various types of crimps of the crimp te tube in FIGS. 17, 18, and 19 are shown. In accordance with the present invention, an example of applying a method in which a liner is fused is presented.

Although the example of the fusion of the socket socket tube, the elbow tube and the tee tube with the liner is shown, it is applicable to the crimp reducer tube, the crimped end cap, the crimped wire tube, etc., but the illustration is omitted. .

When the resin pipe is injected and fused into the inside of the pipe by the above method, the thickness of the resin can be reduced compared to the conventional method. Therefore, the size of the pipe is reduced and the resin pipe is fused to the metal pipe, so that the watertightness is ensured and durability is achieved. Is increased.

In addition, the resin can be fused after injection into a screw pipe or a crimped pipe used in a small pipe.

Claims (10)

In the manufacture of lined by injecting resin into the metal fittings, the adhesive resin is injected into the inner circumferential surface of the metal fittings, and the inner surface of the adhesive resin is injected into the inner surface of the adhesive resin, Threaded and crimped joint pipes, characterized in that they are fused and integrated with the joint pipes In paragraph 1, A screw fitting tube comprising a watertight core and an elastic ring in a screw fitting tube in which a resin tube is injected and fused. In paragraph 2,  The watertight core is connected to a joint pipe by a screw formed on an outer circumferential surface thereof, and has a reinforcing rib on a close contact surface with the connecting pipe. In the manufacturing method of the fitting pipe lined by injecting resin into the metal fitting pipe, Manufacturing a metal fitting tube for the screw by first injecting a resin tube using the screw metal fitting tube as an outer mold; Attaching an injection mold of the adhesive resin to the metal fitting tube; Injecting an adhesive resin tube; Removing the injection mold of the adhesive resin and attaching the injection mold for the inner resin tube: injecting the inner resin tube; Welding the resin pipe to the metal fitting pipe; Cooling the resin tube fusion spliced: A method for producing a screw pipe fusion spliced resin lining in the inner pipe, characterized in that it comprises the step of forming a screw. In the manufacture of the fitting pipe lined by injecting resin into the metal fitting pipe, Using a crimped metal fitting tube as an injection mold to inject a resin tube, but first manufacturing a crimping metal fitting tube; Attaching an injection mold to the metal fitting tube; Injecting an adhesive resin tube; Removing the injection mold of the adhesive resin and attaching the injection mold for the inner resin tube: injecting the inner resin tube; Welding the resin pipe to the metal fitting pipe; A method of manufacturing a crimped fitting tube in which a resin lining is fused to the inside of the fitting tube, comprising: cooling the fitting tube in which the resin is fused. In paragraphs 4 and 5, Injection of the adhesive resin tube and the injection of the inner resin tube is carried out in two stages by a separate insertion mold is carried out in the manufacturing method of the joint of the resin tube fusion spliced inside the joint pipe. In paragraphs 4 and 5, The fusion step is to insert a joint pipe with a plurality of inner surfaces lined in a pressurized fusion furnace, which is sealed and insulated and equipped with a heating means and a pressure regulating means, and pressurized and heated at a time, after injecting a predetermined pressure from the pressure fusion furnace. Method of manufacturing a joint pipe, characterized in that the heating to a temperature of at least 150 degrees to 300 degrees, but preferably to 190 degrees to 250 degrees and to maintain a predetermined time. In paragraph 6, The inner insertion mold is provided separately for adhesive resin and inner surface resin, and each inner insertion mold is divided into a resin injection hole, a heating means, a cooling means, a dowel or a dowel hole for each of the divided inner insertion molds. Injection device of joint pipe. In paragraph 7, Pressurized fusion furnace is equipped with a solenoid valve interlocked with a pressure gauge in the inlet air pipe to maintain the set pressure constant, the inflow of compressed air is controlled and a pressure regulating solenoid valve is also provided in conjunction with the pressure gauge to discharge the high pressure in the fusion furnace Pressurized fusion apparatus of the fitting pipe, characterized in that for controlling. In paragraph 7,  A pressurized fusion path is a pressurized fusion device of a joint pipe, characterized by comprising a circulation pipe, a pump and heating means for inlet compressed air so that the temperature distribution in the furnace is uniform.

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