JPH0245583B2 - - Google Patents

Abstract

PURPOSE:To realize a simple and quick inspection for the condition of the melt- stuck part of the saddle, by pressing a branch saddle made of the synthetic resin and melt-stuck on the outer circumference face of the synthetic resin to deform the saddle into a flat piece for inspection. CONSTITUTION:A branch saddle made of the synthetic resin is melt-stuck and joined on the outer circumference face of a synthetic resin pipe, and then the synthetic resin is pressed at the periphery of the melt-stuck part of the saddle to give a plastic deformation to the saddle. Thus the melt-stuck condition is decided by the state of exfoliation at the periphery of the melt-stuck part. For instance, the periphery of the melt-stuck part is held between pushing plates 41 and 42 from the longitudinal or lateral direction after melt-sticking and joining the branch saddle 2 to the synthetic resin pipe 1, and then a hydraulic cylinder 5 is actuated. Then the saddle is deformed so that its diameter becomes <=1/2 orginal value. In this case, whether or not any exfoliation is caused at a beat part 3 near the melt-stuck part or not is inspected. Thus the melt-stuck condition is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for inspecting the joint state of a fused portion of a synthetic resin pipe after a branch saddle is fused and joined to the outer circumferential surface of a synthetic resin pipe.

Conventionally, when a branch saddle is melt-bonded to the outer circumferential surface of a synthetic resin pipe such as a polyethylene pipe, there are two methods for inspecting the joint condition of the saddle fusion: (1) visual inspection, and (2) pressurized fluid introduction method. etc. were taken. former
Method (1) is a method of determining the bonding condition based on the shape and size of the bead (see bead 3 in Figure 1) that occurs at the saddle weld, but this inspection method requires skill. And so. The latter method (2) is a method in which a branch saddle is melt-bonded to the outer circumferential surface of a synthetic resin pipe, and then a certain internal pressure is applied to the branch saddle and the joint of the saddle fused portion is inspected to see if there is a pressure drop. However, since it takes a certain amount of time to measure the pressure drop, it has the disadvantage that the test takes too much time.

The present invention provides a saddle fusion inspection method that does not require any skill and can be inspected in a short time. After the branch saddle made of resin is melted and bonded, a synthetic resin pipe is pressed separately along the axial direction of the branch saddle and the circumferential direction of the branch saddle at the peripheral edge of the fused portion of the saddle to form a flat shape. The present invention provides a method for inspecting a saddle welded portion, which is characterized by causing elastic deformation to occur.

That is, when the synthetic resin pipe is deformed into a flat shape, the present invention ensures the quality of the joint by checking whether the branch saddle follows this deformation or peels off from the outer peripheral surface of the synthetic resin pipe. There are methods that can be used to test.

The present invention will be explained below with reference to the drawings. Figure 1 shows
Figures 2A and 2B are front views showing a state in which a branch saddle 2 made of the same type of synthetic resin is fused and bonded to the outer peripheral surface of a synthetic resin pipe 1 such as a polyethylene pipe, and the branch saddle 2 is positioned upward. Figures 3A and 3B are inspection process diagrams in which the synthetic resin pipe 1 is pressurized from the left and right sides to elastically deform it into a flat shape. It is.

The branch saddle 2 has a tube connecting portion 21 at one end, and a saddle portion 22 having a joint surface with a radius of curvature approximately equal to that of the synthetic resin tube 1 at the other end. This branch saddle 2 is fused and bonded to the synthetic resin pipe by heating and melting the joint surface of the saddle portion 22 and then pressing it against the outer peripheral surface of the synthetic resin pipe 1, which is simultaneously heated and melted. At this time, if both joint surfaces are melted appropriately, the molten resin protruding from each joint surface will appear as beads 31 and 32 on the periphery of the saddle fusion part, resulting in a joint as shown in Figure 1. can get.

In the present invention, at the peripheral edge of the saddle fusion part where the synthetic resin pipe 1 and the branch saddle 2 are melt-joined,
The synthetic resin pipe 1 is pressed separately in two directions, the axial direction of the branch saddle 2 and the circumferential direction of the branch saddle 2, to elastically deform it into a flat shape and inspect the joint state.

First, in the first inspection, the branch saddle 2 is positioned upward as shown in FIG.
2 and actuate the hydraulic cylinder to press and deform the synthetic resin pipe along the axial direction of the branch saddle. At this time, the press plates 41 and 42 are applied to the peripheral edge of the saddle welded part, that is, the outer peripheral surface of the synthetic resin pipe slightly apart from the beat 3, and the length in the short axis direction is The tube is elastically deformed into a flat shape until the tube diameter D is equal to or less than D/2.

If the fusion bond between the synthetic resin pipe 1 and the branch saddle 2 is incomplete, this pressing operation causes the saddle fusion part to separate along the axial direction of the branch saddle,
Since a gap is created as shown in FIG. 4, poor bonding can be visually confirmed. On the other hand, if the fusion bonding is perfect, the saddle portion 22 deforms following the elastic deformation of the synthetic resin tube 1, so that it will not peel off.

That is, in this first inspection, it is mainly possible to judge whether or not the joint of the branch saddle 2 of the synthetic resin pipe 1 in the axial direction of the branch saddle 2 is good. , a second test described below is performed.

The second inspection is performed by positioning the branch saddle 2 connected to the synthetic resin pipe 1 upward as shown in FIG.
Push plates 41 and 42 are applied to the upper and lower surfaces of the synthetic resin pipe 1, and the hydraulic cylinder 5 is operated to press and deform the synthetic resin pipe. At this time, the press plates 41 and 42 are applied to the outer circumferential surface of the synthetic resin pipe slightly away from the peripheral edge of the saddle fusion part, and the length in the short axis direction is the pipe diameter dimension D as shown in FIG. It is elastically deformed into a flat shape until it becomes D/2 or less.

If the fusion bond between the synthetic resin pipe 1 and the branch saddle 2 is incomplete, this pressing operation causes the saddle fusion part to peel off along the circumferential direction of the branch saddle,
Since a gap is created as shown in FIG. 5, poor bonding can be visually confirmed.

That is, in this second inspection, it is possible to mainly judge whether or not the joint of the branch saddle 2 to the synthetic resin pipe 1 in the circumferential direction of the branch saddle 2 is good.

Therefore, for those that passed the first and second tests, it can be confirmed that the fusion bond between the synthetic resin pipe and the branch saddle is sufficiently good.

Incidentally, in the inspection method of the present invention, there is no particular problem as to which of the above-mentioned inspections is carried out first, and the second inspection may be carried out before the first inspection.

As described above, the present invention makes it possible to reliably judge the quality of the fusion bond between the synthetic resin pipe and the branch saddle simply by elastically deforming the synthetic resin pipe into a flat shape.
It can be suitably used even at construction sites with poor working conditions. Furthermore, the testing method of the present invention includes:
Assuming the worst condition after piping construction, this inspection involves deforming the synthetic resin pipe into a flat shape along two directions: the axial direction of the branch saddle and the circumferential direction of the branch saddle to judge the quality of the fusion bond. For pipes that have undergone this process, there is no risk of fluid leaking from the fused portion after pipe construction. Moreover, the pass or fail of this inspection is determined by whether or not there is peeling at the saddle fusion part.
Since the inspection does not require any skill and can be carried out quickly, there is no need for the inconvenience of time-consuming piping construction.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the joint state of the synthetic resin pipe and the branch saddle, Fig. 2 A and B are side views showing the first inspection process, and Fig. 3 A and B are the second inspection process. FIG. 4 is a side view showing the process; FIG. 4 is a sectional view showing a state in which peeling occurs in the first inspection; and FIG. 5 is a front view showing a state in which peeling occurs in the second test. 1...Synthetic resin pipe, 2...Branch saddle, 3...
Bead, 4...Press plate, 5...Hydraulic cylinder.

Claims (1)

[Claims] 1. After melt-bonding a branch saddle made of the same type of synthetic resin to the outer peripheral surface of a synthetic resin pipe, the synthetic resin pipe is attached at the peripheral edge of the saddle fusion part in the axial direction of the branch saddle and the circumferential direction of the branch saddle. A method for inspecting a saddle fused portion, which comprises pressing separately in two directions to elastically deform it into a flat shape.