KR101223690B1 - Manufacturing method of bended fitting with thermoplastic pipe - Google Patents

Abstract

Disclosed is a method for producing a curved tube using a synthetic resin straight tube for producing a synthetic resin curved tube that is manufactured using a synthetic resin straight tube and has no joint portion formed at a portion bent at a predetermined curvature. According to the present invention, a step of preparing a synthetic resin resin tube selected from a polybutylene tube, a PE tube, a PP tube, or a vinyl chloride resin tube extending in a straight line (S1); Softening the prepared synthetic resin straight pipe (S2); Inserting into the mold having a shape of a curved pipe to be manufactured so that the other end is softened so that the other end is exposed to the outside (S3); Sealing one end of one end or the other end of the synthetic resin straight pipe exposed to the outside of the mold (S4); Molding and cooling the softened synthetic resin straight pipe while blowing air pressure through the open end of the synthetic resin straight pipe inserted into the mold (S5); And when the step (S5) is completed, the step (S6) to complete the production of the curved tube by detaching the mold.

Description

MANUFACTURING METHOD OF BENDED FITTING WITH THERMOPLASTIC PIPE}

The present invention relates to a method for manufacturing a plastic curved pipe, more specifically, using a synthetic resin straight pipe, a curved pipe using a synthetic resin pipe for manufacturing a synthetic resin curved pipe that is not formed in the portion bent at a predetermined curvature It relates to a manufacturing method.

In general, pipes should be selected according to the type of fluid, pressure, temperature used, and installation location. Recently, pipes made of synthetic resins such as polyethylene and polypropylene having excellent chemical resistance, cold resistance, and durability have been used in the transfer of fluids such as water, sewage, and gas.

As anyone can know, the above-described synthetic resin tube is generally produced in a straight shape having a predetermined length, so in order to extend the synthetic resin tube from one point to another point, it is necessary to use the synthetic resin pipes. In particular, the direction of the fluid flowing along the plastic pipe, or to extend the plastic pipe to avoid other structures, or to connect the plastic pipe in a curved line depending on the purpose of use, that is, to create a curved pipe.

In order to make a curved pipe with a straight synthetic resin tube is used conventional pipe joint members. As a conventional pipe joint member, 90 ° elbow, 45 ° elbow, 90 ° band, 45 ° band, or the like is used. That is, it is possible to connect the synthetic resin pipe to have an "L", "U", "Z" or "S" shape using the existing curved pipe described above.

By the way, when the bent pipe using the conventional pipe joint member (elbow or band) described above, there are many joint points connecting the synthetic pipe and the curved pipe, which not only increases the joint construction cost of the synthetic pipe but also increases the number of joint points. There was a problem that the probability of occurrence of defects at the point increases.

In addition, when the bent pipe using the elbow of the pipe joint member described above, since the angle is formed in the inner portion of the elbow, there is a problem of increasing the pressure loss of the flowing fluid.

In addition, the conventional polybutylene pipe, polypropylene pipe, polyethylene pipe, etc. have flexibility, so when the bending radius is a certain degree when piping, the pipe can be bent by bending, but when the bending radius is small, only the pipe joint member must be used. And, even if the flexibility is good, there was a problem that the bending radius should be more than 10 to 15 times the diameter of the bend pipe to form.

The present invention has been made to solve the conventional problems as described above, an object of the present invention, by providing a method for manufacturing a synthetic resin curved pipe without a joint point, reducing the joining cost and the joining portion of the pipe during pipe construction To provide a method of manufacturing a curved pipe using a synthetic resin straight pipe that can lower the defect rate of the pipe and significantly reduce the work time due to the construction of the pipe.

In order to achieve the object of the present invention as described above, the present invention,

Preparing a synthetic resin resin pipe selected from a polybutylene pipe, a PE pipe, a PP pipe, or a vinyl chloride resin pipe extending in a straight line (S1);

Softening the prepared synthetic resin straight pipe (S2);

Inserting into the mold having a shape of a curved pipe to be manufactured so that the other end is softened so that the other end is exposed to the outside (S3);

Sealing one end of one end or the other end of the synthetic resin straight pipe exposed to the outside of the mold (S4);

Molding and cooling the softened synthetic resin straight pipe while blowing air pressure through the open end of the synthetic resin straight pipe inserted into the mold (S5); And

When the step (S5) is completed, the step of removing the mold to complete the production of the curved pipe (S6); provides a method for producing a curved pipe using a synthetic resin straight pipe comprising a.

As described above, according to the present invention,

First, there is an advantage that it is easy to manufacture a curved tube having a variety of bending angles as well as the shape of the standard curved tube.

Secondly, since the pipe joint member is not used as in the prior art, when the bent pipe is formed using the curved pipe manufactured according to the present invention, the connection point is remarkably small, so the piping cost is low, and the joining construction cost and defect of the connection point are There is an advantage that does not occur.

Third, the pressure loss of the fluid flowing inside the pipe can be reduced because there is no inside angle that is bent like a pipe joint member such as a conventional elbow, and when the inside of the pipe is to be cleaned by using a pig (PIG) When the elbow is used as described above, the pigtail (PIG) does not penetrate normally, while the curved pipe manufactured according to the present invention has an advantage that the pigtail (PIG) can smoothly pass.

Hereinafter, a method of manufacturing a curved pipe using a thermoplastic synthetic resin straight pipe according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

≪ Example 1 >

In order to manufacture the curved pipe using the plastic straight pipe according to the first embodiment of the present invention,

First, the ordinary synthetic resin straight pipe extended in a straight line is prepared (step S1).

The synthetic resin straight pipe to be prepared is a conventional polybutylene (PB; Polybutylene) tube, a PE tube made of ordinary polyethylene (PE; Polyethylene), or a PP tube made of ordinary polypropylene (PP; Polypropylene), or Prepare a straight tube of any one selected from a conventional PVC (PVC) tube.

When the synthetic resin straight pipe is prepared, the prepared synthetic resin straight pipe is softened (step S2). Table below. 1 shows the softening condition according to the type of pipe.

table. 1 Softening condition by type of pipe

Softening of synthetic resin straight pipe is done by indirect heating method regardless of the material of straight pipe. The synthetic resin straight pipe is softened by heating the plastic straight pipe to the plasticization temperature, that is, the critical melting point. When the synthetic resin straight pipe is directly heated with a flame (flame) in step S2, the portion overheated due to the homogeneity problem of heat applied to the synthetic resin straight pipe loses its original physical properties.

As a method of indirectly heating the synthetic resin straight pipe, the boiling point is higher than the plasticization temperature of the synthetic resin straight pipe under the method of using a common industrial oven or a common industrial drying furnace or arranging the heating pipe to surround the outer circumferential surface or the inner circumferential surface of the synthetic resin straight pipe. This method comprises any one of the method of using the high heat medium oil or the method of using high pressure steam having a temperature higher than the plasticization temperature of the synthetic resin straight pipe, in the conventional industrial oven or the conventional industrial drying furnace After arranging the synthetic resin straight pipe inside any one, it is preferable to soften the synthetic resin straight pipe by raising the temperature to the plasticization temperature.

Meanwhile, the synthetic resin straight pipe is indirectly heated for 7 seconds to 72 seconds per thickness (mm) of the synthetic resin straight pipe at a temperature of 133 ° C to 173 ° C.

That is, the softening of the polybutylene (PB) tube is indirectly heated for 28 seconds to 34 seconds per mm (mm) while maintaining the temperature of 133 ° C to 143 ° C. The softening of the polyethylene (PE) tube is 145 ° C. Indirect heating is performed for 15 seconds to 23 seconds per mm (mm) while maintaining a temperature of 캜 to 155 캜. In addition, the softening of the polypropylene (PP) pipe is indirectly heated for 66 to 72 seconds per mm (mm) while maintaining the temperature of 160 ° C to 170 ° C, and the softening of the PVC pipe. ) Is indirectly heated for 7 seconds to 13 seconds per mm (mm) while maintaining a temperature of 163 ° C to 173 ° C.

Here, when the heating temperature and the heating time per thickness of the prepared synthetic resin straight pipes are exceeded, the shape of the straight pipe is lost and difficult to process. In particular, the vinyl chloride resin (Sol in the gel state in the case of PVC pipe) When the temperature is easily changed to a state, and the heating temperature and the heating time per thickness are less than the softening of the synthetic resin straight pipe, the working time due to the softening of the plastic straight pipe is long.

On the other hand, the softening of the synthetic resin straight pipe can heat the entire synthetic resin straight pipe, or only the bending portion of the synthetic resin straight pipe.

As described above, when the softening of the synthetic resin straight pipe is completed (step S2), the softened synthetic resin straight pipe is inserted into a mold having the shape of a curved pipe to be manufactured (step S3). At this time, one end and the other end of the softened synthetic resin straight pipe is inserted into the mold to be exposed to the outside of the mold. As can be seen by anyone in step S3, the mold is divided into a lower mold and an upper mold covering the lower mold, and the lower mold and the upper mold are each formed with a groove for manufacturing a curved tube having a shape of a curved tube to be manufactured.

That is, one end and the other end of the softened synthetic resin straight pipe is placed in the groove for manufacturing a curved pipe formed in the lower mold so that the outer mold is exposed to the outside of the lower mold, and then the softened synthetic resin straight pipe is covered with the upper mold on the upper mold. The plastic tube is inserted into the mold.

When the softened synthetic resin straight pipe is inserted into the mold (step S3), one end or the other end of the synthetic resin straight pipe exposed to the outside of the mold is sealed (step S4). The sealing of the synthetic resin straight pipe is sealed by attaching either a cap or a rubber stopper to the end, or by sealing the end by using a common wire.

Then, the softened synthetic resin straight pipe is molded and cooled while blowing air pressure through the open end of the synthetic resin straight pipe inserted into the mold (step S4). When the air pressure is blown into the synthetic resin straight pipe inserted into the mold, the softened synthetic resin straight pipe has a shape of a curved pipe to be manufactured while being in close contact with the groove for manufacturing a curved pipe formed in the lower mold and the upper mold. The air blowing is blown until the softened plastic pipe is cooled. At this time, if the blown air flow is stopped while the softened synthetic resin straight pipe is not cooled, the softened synthetic resin straight pipe is shrunk or deformed so that the air pressure is maintained until the synthetic resin straight pipe is cooled. Table below. 2 shows cooling conditions according to the type of pipe.

table. 2 Cooling condition by type of pipe

Here, the blowing pressure is suitable for the pressure not to exceed 1/10 of the working pressure of the curved pipe to be manufactured. For example, if the curved pressure exceeds 1/10 of the working pressure, the pressure is too high to swell or rupture the softened part that is not covered by the mold.If the curved pressure does not reach 1/10 of the working pressure, the pressure is too low to bend. The roundness of the site is not good, that is, it does not work with the force of expansion.

On the other hand, the blowing time and cooling time is cooled while blowing for 1 second to 13 seconds per thickness (mm) of the synthetic resin straight pipe. That is, the cooling of the polybutylene (PB) pipe is cooled by blowing for 2 seconds to 8 seconds per thickness (mm), and the cooling of the polyethylene (PE) pipe by cooling by blowing for 7 seconds to 13 seconds per thickness (mm). do. And the cooling of the polypropylene (PP) pipe is cooled by blowing for 5 to 11 seconds per thickness (mm), the cooling of the vinyl chloride resin (PVC) pipe by cooling by blowing for 1 to 5 seconds per thickness (mm) do.

As such, when the cooling of the synthetic resin straight pipe inserted into the mold is completed, the lower mold and the upper mold are detached to complete the curved pipe manufacturing (step S6).

<Example 2>

 In order to manufacture the curved pipe using a synthetic resin straight pipe according to a second embodiment of the present invention,

First, a normal synthetic resin straight tube extending in a straight line is prepared, and a coil spring is inserted into the prepared synthetic resin straight tube (step S10).

The synthetic resin straight pipe to be prepared is a conventional polybutylene (PB; Polybutylene) tube, a PE tube made of ordinary polyethylene (PE; Polyethylene), or a PP tube made of ordinary polypropylene (PP; Polypropylene), or Prepare a straight tube of any one selected from a conventional PVC (PVC) tube.

On the other hand, the coil spring is preferably equal to the length of the curved pipe to be manufactured, or longer than the length of the curved pipe to be manufactured, the coil spring diameter is smaller than the diameter of the synthetic resin straight pipe prepared to be easily inserted into the prepared plastic straight pipe It is preferred to have a diameter. Such coil springs serve to maintain the original shape of the pipe during the manufacture of the curved pipe.

When the coil spring is inserted into the prepared synthetic resin straight pipe, the portion to be bent is softened (step S20).

Softening of synthetic resin straight pipe is done by indirect heating method regardless of the material of straight pipe. The synthetic resin straight pipe is softened by heating the plastic straight pipe to the plasticization temperature, that is, the critical melting point. When the synthetic resin straight pipe is directly heated with a flame (flame) in step S20, the portion overheated due to the homogeneity problem of heat applied to the synthetic resin straight pipe loses its original physical properties. Table below. 3 shows the softening conditions according to the type of pipe.

table. 3 softening conditions according to the type of pipe

In addition, as an indirect heating method of the synthetic resin straight pipe, the portion to be bent is heated with thermal medium oil, and the thermal medium oil adopts that chemical reaction does not occur with the synthetic resin straight pipe.

Meanwhile, the synthetic resin straight pipe is indirectly heated for 7 seconds to 72 seconds per thickness (mm) of the synthetic resin straight pipe at a temperature of 133 ° C to 173 ° C.

That is, the softening of the polybutylene (PB) tube is indirectly heated for 28 seconds to 34 seconds per mm (mm) while maintaining the temperature of 133 ° C to 143 ° C. The softening of the polyethylene (PE) tube is 145 ° C. Indirect heating is performed for 15 seconds to 23 seconds per mm (mm) while maintaining a temperature of 캜 to 155 캜. In addition, the softening of the polypropylene (PP) pipe is indirectly heated for 66 to 72 seconds per mm (mm) while maintaining the temperature of 160 ° C to 170 ° C, and the softening of the PVC pipe. ) Is indirectly heated for 7 seconds to 13 seconds per mm (mm) while maintaining a temperature of 163 ° C to 173 ° C.

Here, when the heating temperature and the heating time per thickness of the prepared synthetic resin straight pipes are exceeded, the shape of the straight pipe is lost and difficult to process. In particular, the vinyl chloride resin (Sol in the gel state in the case of PVC pipe) When the temperature is easily changed to a state, and the heating temperature and the heating time per thickness are less than the softening of the synthetic resin straight pipe, the working time due to the softening of the plastic straight pipe is long.

As described above, when the softening of the synthetic resin straight pipe is completed (step S20), the softened synthetic resin straight pipe is molded and cooled to have a shape of a curved pipe to be manufactured (step S30). The softened synthetic resin straight pipe is formed by winding a portion to be bent, that is, a softened portion, by a desired angle in a cylindrical rotary disk (Roguro), and then immersing in a cooling water together with the rotary disk to cool.

When the molding and cooling is completed in the above-described step (S30), the rotating disk (Roguro) and the coil spring is removed to complete the curved pipe manufacturing (step S40).

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims You will understand.

Claims (16)

After preparing a thermoplastic synthetic resin straight pipe selected from a polybutylene (PB) pipe, a polyethylene (PE) pipe, and a polypropylene (PP) pipe extending in a straight line, a coil spring is inserted into the straight pipe, and the selected straight pipe is critical. The next condition that is the melting point
P) PB pipe has heating temperature (℃) of 138 ± 5 and heating time / thickness (sec / mm) of 31 ± 3
Ii) PE pipe has heating temperature (℃) of 150 ± 5 and heating time / thickness (sec / mm) of 18 ± 3
PP) PP pipe has heating temperature (℃) of 165 ± 5, heating time / thickness (sec / mm) of 69 ± 3
After the softening by using a rotary disk molded into a shape to be produced, and then cooled to be cured as it is a method for producing a curved pipe using a synthetic resin straight pipe, the softening is to bend the portion to be bent per thickness of the straight pipe Indirect heating with a heat medium oil for 7 to 72 seconds at a temperature of 133 ~ 173 ℃, the cooling is carried out by immersing the straight pipe softened with the turntable in the cooling water, the production of curved pipe using a straight pipe synthetic resin Way. The method of claim 1,
When molding into a desired shape, the softened part is wrapped in a mold, and then the end of one or the other end of the tube is sealed, and the synthetic resin straight pipe is formed by cooling and blowing air pressure through the unsealed end. Method for producing a curved pipe used. delete The method of claim 2,
In softening, indirect heating is used, and an industrial oven or an industrial drying furnace is used, or a heating oil having a boiling point higher than the critical melting point temperature of the straight pipe is disposed under the condition that the heating pipe is wrapped around the outer or inner circumferential surface of the straight pipe, A method for producing a curved pipe using a synthetic resin straight pipe, characterized in that the heating by any one of the method using a high pressure steam having a temperature higher than the critical melting point temperature of the straight pipe. The method of claim 4, wherein
When softening, the method for producing a curved pipe using a synthetic resin straight pipe, characterized in that the entire indirect pipe is heated indirectly, or only the portion to bend the straight pipe is indirectly heated. The method of claim 2,
The mold is divided into a lower mold and an upper mold, and each of the lower mold and the upper mold is formed with a curved pipe manufacturing groove having a shape of a curved pipe to be manufactured, and each of the curved pipe manufacturing grooves is provided with a softened straight pipe. Method for producing a curved pipe using a synthetic resin straight pipe characterized in that. The method of claim 2,
When the end is sealed, a cap or rubber stopper is sealed at the end of the straight pipe, or a method of manufacturing a curved pipe using a synthetic resin straight pipe, characterized in that the end is sealed by using a wire. The method according to claim 6,
The air pressure is a method of manufacturing a curved pipe using a synthetic resin straight pipe, characterized in that the soft pipe is inflated to be in close contact with the groove for manufacturing the curved pipe formed in the lower mold and the upper mold. delete The method of claim 8,
The air pressure is a method for producing a curved pipe using a synthetic resin straight pipe, characterized in that the pressure does not exceed 1/10 of the operating pressure of the curved pipe to be manufactured. 11. The method of claim 10,
The cooling time of the air pressure is the following conditions
P) PB pipe has a cooling time / thickness (sec / mm) of 5 ± 3
Ii) PE pipe has a cooling time / thickness (sec / mm) of 10 ± 3
관) PP pipe has cooling time / thickness (sec / mm) of 8 ± 3
Method for producing a curved pipe using a synthetic resin straight pipe characterized in that. delete delete delete delete delete