TWI821261B - Manufacturing method of resin piping, and resin piping - Google Patents

Abstract

The present invention provides a resin pipe manufacturing method that can effectively prevent large positional deviation or step difference between the ends after welding of a resin pipe member and a resin pipe joint or other resin pipe member, and a resin pipe manufacturing method. Preparation of piping. The manufacturing method of resin pipes of the present invention is a method of manufacturing resin pipes by connecting the resin pipe member 1 to the resin pipe joint 21 or other resin pipe members, and includes the following steps: End diameter expansion step: enlarging the inner and outer diameters of the end portions 2 of the resin tubular member 1 molded from a resin material relative to the inner and outer diameters of the remaining portions 3 of the resin tubular member 1 so that the end portions 2 have an enlarged diameter. end 2a; and End welding step: heating the enlarged diameter end 2a of the resin pipe member 1 and the resin pipe joint 21 connected to the resin pipe member 1 or the end 22 of other resin pipe members together. By melting, the enlarged diameter end portion 2a and the end portion 22 are butt-jointed and welded.

Description

Manufacturing method of resin piping, and resin piping

The present invention relates to a method of manufacturing a resin pipe in which a resin pipe member and a resin pipe joint or other resin pipe member are connected by welding the ends thereof, and a resin pipe. In particular, the present invention proposes a method A technology that helps improve the quality of resin piping.

Resin pipes such as chemical liquid conveying lines used in various industries are sometimes manufactured by welding the respective ends of resin pipe joints or resin pipe members made of thermoplastic resin or the like to each other using a welding machine. .

Describing in detail an example of a method for manufacturing such a resin pipe, for example, a pair of clamping jigs of a welding machine are each held in an attitude such that the ends of two resin pipe members or resin pipe joints face each other. The two resin pipe body members or resin pipe joints. Next, by heating the respective ends of the two resin pipe members held by the respective clamping jigs with a heater or the like, the ends are melted, and in this state, the two resin pipe members are The components are brought close to each other, and the required pressure is used to make the ends butt for welding. By repeatedly welding the ends of such resin pipe members and the like, a pipe of a predetermined shape can be manufactured.

In such a resin pipe, it is preferable to prevent as much as possible the occurrence of positional deviation or step difference in the inner surface between the welded ends of the resin pipe member or the resin pipe joint. The reason is that this positional shift or step will become the main cause of the decrease in welding strength at the end, which may lead to breakage or cracks at the welded end due to deterioration due to long-term use or external force.

In addition, Patent Document 1 proposes that when the resin pipe joints are welded at their ends, for the purpose of preventing positional deviation of the ends of the resin pipe joints that are welded to each other, for example, the outer surface of the resin pipe joints is provided with The fixed part held by the clamping jig of the welding machine. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 5710450

[Problem to be solved by the invention]

However, it is known that in a resin tubular member obtained by molding a resin material into a tubular shape, if the end portions to be welded to each other using a welding machine or the like are heated and melted, the end portions will become tapered. diameter deformation. Furthermore, if the ends of the resin pipe member are directly welded to a resin pipe joint or other resin pipe member in this state, a large positional deviation may occur in the inner surface between the welded ends. Or the problem of step difference.

The present invention aims to solve such problems existing in the prior art, and its purpose is to provide a method that can effectively prevent the occurrence of large gaps between the ends of resin pipe members and resin pipe joints or other resin pipe members after they are welded. Method for manufacturing resin pipes with positional deviation or step difference, and resin pipes. [Technical means to solve the problem]

The manufacturing method of resin pipes of the present invention is a method for manufacturing resin pipes by connecting a resin pipe member to a resin pipe joint or other resin pipe member, and includes the following steps: The end diameter enlarging step: enlarging the inner and outer diameter of the end of the resin pipe member molded from the resin material relative to the inner and outer diameter of the remaining portion of the resin pipe member so that the end becomes an expanded diameter end; and End welding step: heating and melting the enlarged diameter end of the resin pipe member and the end of a resin pipe joint or other resin pipe member connected to the resin pipe member to fuse the expanded diameter. The diameter end and the end are butt-jointed for welding.

Here, in the end diameter expanding step, it is preferable that the diameter expanding jig is inserted into the inside of the end portion of the resin pipe member to expand the inner and outer diameters of the end portion. In this case, it is preferable that the diameter expansion jig includes an insertion portion inserted into an end portion of the resin pipe member, and the insertion portion has a tapered outer peripheral surface whose outer diameter gradually increases from the front end side toward the rear side.

Furthermore, it is preferable that in the end diameter expanding step, the diameter-enlarged end portion of the resin pipe member is configured such that the inner and outer diameters gradually increase toward the end face side of the diameter-enlarged end portion in at least a portion of the diameter-enlarged end portion. of cone.

In any of the above-mentioned manufacturing methods of resin pipes, it is preferable that when connecting the resin pipe member and other resin pipe members, in the end diameter expansion step, the resin pipe member and other resin pipe members are connected to each other. The inner and outer diameters of the respective ends of the tubular body member are enlarged so that each of the above-mentioned ends becomes an enlarged diameter end. In the end welding step, the enlarged diameter end portions of the above-mentioned resin-made tubular member and other resin-made tubular members are Welded to each other.

Furthermore, in any of the above-mentioned manufacturing methods of resin pipes, it is preferable that when connecting the resin pipe member and the resin pipe joint, in the end diameter expansion step, only the resin pipe member and the resin pipe joint are used. The inner and outer diameters of the ends of the resin pipe body members in the pipe joint are enlarged.

The resin piping of the present invention includes a resin pipe member and a resin pipe joint or other resin pipe member that is fused and connected to the resin pipe member at its end. The resin pipe is connected to the resin pipe member. Before the step of welding the member to the end of the resin pipe joint or other resin pipe member, the inner and outer diameter of the end of the resin pipe member is enlarged compared to the end of the remaining part of the resin pipe member. It is manufactured by the diameter expansion step, and the step difference in the inner surface of the connecting portion between the above-mentioned resin pipe member and the resin pipe joint or other resin pipe member is 0.4 mm or less based on the average circumferential direction of the inner surface. . [Effects of the invention]

According to the present invention, in the end diameter enlarging step preceding the end welding step, the inner and outer diameters of the ends of the resin pipe members are enlarged so that the ends become diameter-enlarged ends. If the diameter-reducing end of the resin pipe member is deformed due to heating during the partial welding step, it will return to an inner diameter close to the inner diameter before expansion. Therefore, it is possible to effectively prevent the occurrence of large diameters between the ends after welding. position offset or step difference.

Hereinafter, embodiments of the present invention will be described in detail. A method of manufacturing a resin pipe according to one embodiment of the present invention is a method of manufacturing a resin pipe by connecting a resin pipe member to a resin pipe joint or other resin pipe member. Specifically, the method includes the following steps : The end diameter enlarging step: enlarging the inner and outer diameter of the end of the resin pipe member molded from the resin material relative to the inner and outer diameter of the remaining portion of the resin pipe member so that the end becomes an expanded diameter end; and End welding step: Heat and fuse the enlarged diameter end of the resin pipe member and the end of the resin pipe joint or other resin pipe member together, and butt the enlarged end and the end to weld. In addition, the resin piping refers to a piping in which the resin pipe body member or the resin pipe joint constituting the main part is made of a resin material, and may also include members made of materials other than resin, such as metal.

The resin pipe member used in the end diameter expansion step may be formed by cutting a long tubular raw material obtained by subjecting a resin material to predetermined molding such as extrusion molding to a predetermined length in the cutting step. , this embodiment, as illustrated in Figure 1, further includes the cutting step before the end diameter enlarging step. Here, each step will be described in detail below according to the flow chart of FIG. 1 . However, the method of forming the resin pipe member is not particularly limited, and the resin pipe member can be purchased or prepared by any other method, so the cutting step can be omitted. (cutting step)

In the cutting step, generally, a long tubular raw material formed by extrusion molding is cut into a predetermined length corresponding to the location used in the resin pipe to be produced, thereby forming one or more resin pipes. Pipe body components. The raw materials for resin pipe bodies usually take the form of straight or curved straight pipes or curved pipes. This cutting step can be divided into two processes, for example, a first stage of cutting the long tubular material roughly, and a second stage of cutting of the long tubular raw material while finishing the end face while cutting it to a predetermined length with high precision.

Examples of the resin material constituting the long tubular raw material include perfluoroalkoxyalkane (PFA), perfluoroethylene propylene copolymer (FEP), polyether ether ketone (PEEK), etc., but those listed here can also be used. Materials other than materials. The resin pipe joint or other resin pipe member whose end is welded to the resin pipe member in the end welding step described below may be formed of the same resin material. In addition, resin pipe joints are generally formed by injection molding using a predetermined mold, and have an elbow in which the internal flow path is bent into a substantially L-shape, or the internal flow path branches in the middle to form a T-shape, etc. There are various types of joints such as tee joints and reducer joints whose cross-sectional area of the internal flow path changes midway. (End diameter expansion step)

In the end diameter enlarging step, the inner diameter and outer diameter (i.e., the inner and outer diameters) of the end of the resin pipe member are enlarged compared to the inner and outer diameters of the remaining portion of the resin pipe member, thereby making the end The portion becomes the enlarged diameter end portion whose inner and outer diameters are larger than the remaining portion.

Assuming that the following end welding step is performed without the end diameter expansion step, when the end of the resin pipe member is heated in the end welding step, the residual stress generated by extrusion molding, etc. is released by the heating , the heated end is tapered and deformed in diameter toward its end surface. If this end is welded to the end of a resin pipe joint or other resin pipe member in this state, a large step or positional deviation will occur on the inner surface, which will become the Reasons for loss of strength, breakage or cracks. On the other hand, this embodiment anticipates the diameter reduction deformation of the end of the resin pipe member when heated in the end welding step, and performs the end diameter expansion step before the end welding step. In the end diameter expansion step, the deformation amount of the end during heating can be taken into consideration to expand the diameter of the end. Therefore, it can effectively prevent large internal surface steps and positions when welding the end in the end welding step. offset.

The diameter expansion of the end portion of the resin pipe member can be achieved, for example, by the method shown in FIG. 2 . As shown in FIG. 2 , a diameter expanding jig 11 insertable into the end portion 2 of the resin pipe member 1 is used. Specifically, the diameter expansion jig 11 shown in the figure has a roughly cylindrical shape as a whole, and includes a cylindrical base 12 and a cylindrical base 12 disposed on the front end side of the base 12 (right side in FIG. 2 ) and inserted into the resin pipe member 1 . Insert 13 of end 2. The insertion portion 13 is bulged from the base portion 12 and has a tapered outer peripheral surface 13 a whose outer diameter gradually increases from the front end side toward the rear side (the left side in FIG. 2 , that is, the base portion 12 side). In the example shown in the figure, the outer circumferential surface 13a of the insertion portion 13 may be curved in a slightly outwardly convex curve in the longitudinal cross-section, or may be formed in a shape in which the outer diameter increases linearly although not shown in the figure. . The outer diameter of the insertion portion 13 of the diameter expansion jig 11 can be smaller than the inner diameter of the end portion 2 of the resin pipe member 1 on the front end side and larger than the inner diameter of the end portion 2 on the rear side.

When using such a diameter-expanding jig 11, first, as shown by the arrow in FIG. The end portion 2 of the body member 1 is inserted into the insertion portion 13 of the diameter expansion jig 11 . In this way, as the end portion 2 of the resin-made tubular member 1 is inserted into the insertion portion 13, as shown in FIG. The outer circumferential surface 13a of the insertion portion 13 has an inner diameter that is widened and enlarged in diameter. In this case, the inner diameter and the outer diameter of the end portion 2 of the resin pipe member 1 are enlarged. On the other hand, the remaining portion 3 on the inside of the resin pipe member 1 that has not been reached by the insertion portion 13 maintains the original inner and outer diameters.

Thereby, as shown in FIG. 3 , the end portion 2 of the resin pipe member 1 becomes an enlarged diameter end portion 2 a with an inner and outer diameter larger than that of the remaining portion 3 .

When the diameter expansion jig 11 is used to expand the diameter of the end portion 2 of the resin pipe member 1, if the insertion portion 13 of the diameter expansion jig 11 is pulled out from the end portion 2 of the resin pipe member 1, the expanded diameter may be removed. When the diameter jig 11 is taken out from the resin pipe member 1, as time passes, the diameter-enlarged end portion 2a of the resin pipe member 1 gradually shrinks in diameter and returns to its original shape.

Therefore, after taking out the diameter expansion jig 11 from the resin pipe member 1, it is preferable to supply the resin pipe member 1 to the following end welding step as quickly as possible.

In addition, by extending the time for inserting the insertion portion 13 of the diameter-expanding jig 11 into the end portion 2 of the resin-made pipe member 1 to a certain extent, the diameter-expanding jig 11 can be removed from the resin-made pipe member 1 , the shape in which the diameter-expanded end portion 2a of the resin pipe member 1 is expanded is maintained for a relatively long period of time. When the insertion time of the diameter expansion jig 11 is short, there is a possibility that the shape of the diameter expansion end 2a of the resin pipe member 1 cannot be maintained until the end welding step. On the other hand, when the insertion time is long, There is a risk of lowering productivity.

The diameter-expanded end portion 2 a of the resin pipe member 1 obtained using the diameter-expanding jig 11 usually has a shape that imitates the shape of the outer peripheral surface of the insertion portion 13 of the diameter-expanding jig 11 . At least a part of the diameter-enlarged end portion 2a of the resin pipe member 1 shown in Fig. 3, and most of it at this time, has a tapered shape in which the inner diameter and the outer diameter gradually increase toward the end surface 4 side of the diameter-expanded end portion 2a. Alternatively, although illustration is omitted, by appropriately selecting the shape of the insertion portion of the diameter expansion jig, the inner and outer diameters of the expanded end portions can be sharply expanded at the interface with the remaining portion and become fixed from there toward the end surface. The inner and outer diameters have various shapes such as a substantially quadrangular shape or a polygonal shape when viewed in longitudinal section.

The ratio (Da/D) of the inner diameter Da of the end face 4 of the enlarged end portion 2a to the inner diameter D of the remaining portion 3 can be determined appropriately. However, if the inner diameter Da of the end face 4 of the enlarged end portion 2a is relatively If the ratio (Da/D) of the inner diameter D of the remaining portion 3 is too small, the diameter expansion of the expanded end portion 2a will not be enough to effectively suppress the diameter reduction deformation during heating in the end welding step, so it cannot be ruled out that it will occur after welding. Possibility of internal surface step differences or positional shifts. On the other hand, if the ratio (Da/D) of the inner diameter Da of the end surface 4 of the diameter-enlarged end portion 2a to the inner diameter D of the remaining portion 3 is too large, there is a risk that the expansion jig 11 will be inserted due to excessive load. There is a risk of cracks (cracks) etc. occurring.

In addition, the length L along the axial direction of the diameter-enlarged end portion 2a can be a length that causes diameter reduction deformation when heated in the end welding step, and this length L can be set as the end portion 2 of the resin pipe member 1 The scope of diameter expansion.

In addition, in addition to the method shown in FIG. 2 , although the illustration is omitted, for example, a balloon in a contracted state can be inserted into the end portion 2 of the resin pipe member 1 and the balloon can be inflated inside the end portion 2 , so that the inner and outer diameters of the end portion 2 are enlarged, so that the end portion 2 becomes an enlarged diameter end portion. (End welding step)

The resin pipe member 1 having the enlarged diameter end portion 2a obtained through the above-mentioned end portion diameter expansion step can be supplied to the end welding step for connecting to a resin pipe joint or other resin pipe member. Furthermore, this connection can be repeated to produce a resin pipe having a desired shape.

When the diameter-enlarged end portion 2a of the resin pipe member 1 and the end portion of the resin pipe joint are welded to each other, for example, a pair of clamping jigs of a welding machine (not shown) are filled with the resin to be connected to each other. The diameter-enlarged end portion of the tubular member and the end portion of the resin pipe joint are maintained in a position facing each other, so that the resin tubular member 1 and the resin pipe joint are maintained. Then, as shown in FIG. 4 , the diameter-enlarged end portion 2 a of the resin pipe member 1 and the end portion 22 of the resin pipe joint 21 are heated and melted using a heater 31 or the like. Next, in this state, the resin pipe member 1 and the resin pipe joint 21 are brought close to each other, and the enlarged diameter end portion 2a and the end portion 22 are brought into contact with each other by the required pressure.

Here, when the diameter-expanded end portion 2a of the resin pipe member 1 is heated, even if the diameter-expanded end portion 2a undergoes diameter-reducing deformation into a tapered shape, in this embodiment, the end portion diameter-expanding step is performed as described above. The inner and outer diameters are enlarged in advance, so as shown by the arrows in Fig. 4, the enlarged diameter end portion 2a will substantially return to the original size before the diameter expansion. This allows the diameter-enlarged end portion 2a of the resin pipe member 1 to have an inner diameter that is approximately the same as the end portion 22 of the resin pipe joint 21, thereby preventing the inner surface step and positional deviation from occurring there after welding. As a result, the required welding strength of the enlarged diameter end portion 2a and the end portion 22 is ensured, and even if used for a long time or external force is applied, breakage or cracks at the welded expanded diameter end portion 2a and the end portion 22 can be effectively prevented. .

In addition, when the respective ends of two resin-made pipe members are welded to each other, it is preferable that both one resin-made pipe member and the other resin-made pipe members are produced through the above-described end-diameter-expanding step. Thereby, it is possible to suppress diameter reduction deformation during heating and melting before the ends of the resin pipe members are welded, and to more effectively prevent generation of steps or positional deviations.

In the piping produced in this way, the step difference in the inner surface between the welded ends of the resin pipe member and the resin pipe joint or other resin pipe member will be generated at the end. When measured in the radial direction, the average value in the circumferential direction can be made to be 0.4 mm or less, and further can be made to be 0.3 mm or less. The average value of this step difference is the average of the values measured using a microscope at four measurement points at equal intervals in the circumferential direction.

1‧‧‧Resin pipe member 2‧‧‧End 2a‧‧‧Expanded end 3‧‧‧Remainder 4‧‧‧End face 11‧‧‧Diameter expansion jig 12‧‧‧Base 13‧‧‧Insertion part 13a‧‧‧Outer peripheral surface 21‧‧‧Resin pipe joint 22‧‧‧End 31‧‧‧Heater D‧‧‧The inner diameter of the remaining portion of the resin pipe member Da‧‧‧The inner diameter of the end face of the enlarged diameter end of the resin pipe member L‧‧‧Axis length of the enlarged diameter end of the resin pipe member

FIG. 1 is a flowchart showing a resin pipe manufacturing method according to one embodiment of the present invention. FIG. 2 is a longitudinal cross-sectional view along the central axis showing an example of the end diameter enlarging step of the embodiment of FIG. 1 . FIG. 3 is a longitudinal cross-sectional view showing the diameter-enlarged end portion of the resin pipe member obtained in the end-diameter expanding step of FIG. 2 . FIG. 4 is a longitudinal cross-sectional view showing the state during heating in the end welding step of the embodiment of FIG. 1 .

1‧‧‧Resin pipe member

2‧‧‧End

3‧‧‧Remainder

4‧‧‧End face

11‧‧‧Diameter expansion jig

12‧‧‧Base

13‧‧‧Insertion part

13a‧‧‧Outer peripheral surface

Claims (7)

A method for manufacturing resin pipes. The method connects a resin pipe member to a resin pipe joint or other resin pipe members to manufacture a resin pipe. The method includes the following steps: an end diameter expansion step: The inner and outer diameter of the end of the resin pipe member molded from the resin material is enlarged from the inner and outer diameter of the remaining part of the resin pipe member, so that the end becomes an enlarged diameter end; and the step of welding the end is: The enlarged diameter end of the pipe member and the end of a resin pipe joint or other resin pipe member connected to the resin pipe member are heated and melted together, and the expanded diameter end and the end are butted and welded ; After the end diameter expansion step, the diameter expansion end of the resin pipe member is reduced in diameter, and the end welding step is performed before the inner and outer diameters of the diameter expansion end return to the size before expansion. The manufacturing method of a resin pipe according to claim 1, wherein in the end diameter expanding step, a diameter expanding jig is inserted into the inside of the end of the resin pipe member so that the end is The inner and outer diameters are enlarged. The manufacturing method of a resin pipe according to Claim 2, wherein the diameter expansion jig includes an insertion portion inserted into an end portion of the resin pipe member, and the insertion portion has an outer diameter extending from the front end side toward the rear side. Tapered outer circumference with increasing diameter. The manufacturing method of a resin pipe according to any one of claims 1 to 3, wherein in the end diameter expansion step, the diameter-expanded end of the resin pipe member is made to be at the diameter-expanded end. At least a portion has a tapered shape in which the inner and outer diameters gradually increase toward the end face side of the diameter-enlarged end portion. The manufacturing method of a resin pipe according to any one of claims 1 to 3, wherein when connecting the resin pipe member to another resin pipe member, in the end diameter expanding step, the resin is The inner and outer diameters of respective ends of the pipe body member and other resin pipe body members are enlarged so that each end becomes an enlarged diameter end, In the end welding step, the diameter-enlarged end portions of the resin pipe member and other resin pipe members are welded to each other. The method for manufacturing a resin pipe according to any one of claims 1 to 3, wherein when connecting the resin pipe member and the resin pipe joint, in the end diameter expansion step, only the resin pipe member is In the pipe member and the resin pipe joint, the inner and outer diameters of the ends of the resin pipe member are enlarged. A resin pipe including a resin pipe member and a resin pipe joint or other resin pipe member connected by end butt welding to the resin pipe member, the resin pipe being connected to the resin pipe Before the step of welding the body member to the end portion of the resin pipe joint or other resin pipe member, the inner and outer diameter of the end portion of the resin pipe member is enlarged from the inner and outer diameter of the remaining portion of the resin pipe member. It is manufactured by a step of enlarging the diameter of the resin pipe member. The step difference in the inner surface of the connecting portion between the resin pipe member and the resin pipe joint or other resin pipe member is 0.4 mm based on the average circumferential direction of the inner surface. the following.