JPS6255494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for inspecting a connection state when a thermoplastic synthetic resin pipe and a thermoplastic synthetic resin pipe joint are socket fused together.

The prior art will be explained with reference to FIG. Pipe body 1 made of thermoplastic synthetic resin such as polyethylene
When socket-fusion-bonding the pipe body 1 and pipe joint 2, the outer peripheries of the pipe body 1 and pipe joint 2 are held by clamp members 3 and 4, respectively. Next, after heating the end outer periphery 1a of the tube body 1 and the socket 2a of the pipe joint 2 with a heater (not shown), the tube body 1 is fitted into the socket 2a of the pipe joint 2, and the two are fused together. At this time of fitting, when the pipe body 1 is fitted by a predetermined length, the outer circumference 1a of the pipe body 1 and the pipe joint 2
The molten resin in the socket 2a is pushed out to the end surface 2b of the pipe fitting 2 on the pipe body 1 side. Therefore, when this molten resin is sufficiently extruded, the outer periphery 1a of the tube body 1 and the socket 2a of the pipe fitting 2 are sufficiently crimped together, and a good fused state is obtained.

However, when heating the socket 2a of the pipe fitting 2 with a heater, the socket 2a is not attached to the end surface 2b of the pipe fitting 2.
Some of the molten resin has already flowed out. Moreover, the end surface 3a of the conventional clamp member 3 on the side of the pipe fitting 2 is a planar shape perpendicular to the axis of the pipe body 1;
a is pressed against the end surface 2b of the pipe joint 2. Therefore, the molten resin on the end surface 2b that flows out during heating by the heater and the molten resin that flows out when the tube body 1 is inserted into the pipe joint 2 are crushed between the end surfaces 3a and 2b. Moreover, the pipe body 1 and the pipe joint 2 are often of the same color and made of the same material. Therefore,
It is difficult to determine whether the bead 5 formed on the end surface 2b of the pipe fitting 2 after the completion of the fusion operation was generated during the heating process or during the fusion of the pipe body 1 and the pipe fitting 2. be. Therefore, it was not possible to inspect whether the pipe body 1 and the pipe joint 2 were reliably fused together.

An object of the present invention is to provide an inspection method that can easily and reliably determine the state of fusion based on the shape of a bead formed on the end face of a pipe joint after socket fusion is completed.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of one embodiment of the present invention.
A tube body 6 made of a thermoplastic synthetic resin, such as polyethylene, and a pipe joint 7 made of a thermoplastic synthetic resin, such as polyethylene, are held by a clamp member 8 and a clamp member 9, respectively, as annular bodies. The end outer periphery 6a of the pipe body 6 and the pipe joint 7
The socket 7a is heated by a heater 30 (see FIG. 4, which will be described later), and then the tube body 6 is inserted into the socket 7a of the pipe joint 7 to fuse them together. After the welding operation is completed, it can be determined whether the welding has been performed reliably based on the shape of the bead formed on the end surface 7b of the pipe joint 7.

FIG. 3 is a sectional view taken along the section line - in FIG. 2. The clamp member 8 includes a pair of half-split members 9 and 10 having inner circumferences that contact the outer circumference of the tube body 6 by approximately half a circumference, and one end portion of both half-split members 9 and 10 is parallel to the axis of the tube body 6. They are mutually supported by pins 11. At the other end portions of the half members 9, 10, projections 12, 13 are provided, respectively, which protrude outward along a substantially radial direction. One protrusion 1
2, a lever 14 is pivotally supported by a pin 15 parallel to the pin 11. In the middle of the lever 14, one end of a connecting ring 16 is rotatably supported around an axis parallel to the pin 15. Connecting ring 16
The other end is a locking groove 17 formed in the other protrusion 13.
It can be locked to. When the lever 14 is rotated around the pin 15 as shown in FIG. 3 with the connecting ring 16 locked in the locking groove 17, the half members 9, 10
The other end abuts, and the clamp member 8 is fixed to the tube body 6. On the outer periphery of both half members 9 and 10,
Grip rod 1 protruding radially outward on one diameter line
8 and 19 are fixed.

The clamp member 9 has the same structure as the clamp member 8, and can be opened and closed around a pin 20 parallel to the axis of the pipe joint 7.

According to the present invention, in the end face of the clamp member 8 closer to the pipe joint 7, that is, in the end faces of both half-bridge members 9 and 10, a recess is formed that is radially inward and open to the inner circumferential surface. With the clamp member 8 fixed to the tube body 6, an annular recess 21 is formed in the end surface 8a of the clamp member 8. The width d1 of the recess 21 along the radial direction is selected to be approximately 1/3 to 3/5 of the wall thickness d3 of the pipe joint 7 (d1 = 1/3 d3 to 3/5 d3). Further, the depth d2 of the recess 21 is selected to be approximately 0.5 to 1 mm.

When welding the pipe body 6 and the pipe joint 7,
As shown in FIG. 4, the outer periphery 6a of the end portion of the tube body 6 and the socket 7a of the pipe joint 7 are heated by the heater 30. The heater 30 is provided with heating protrusions 22 and 23 having heating surfaces 22a and 23a for heating the end outer periphery 6a and the socket 7a, respectively.
Both heating protrusions 22 and 23 protrude in opposite directions on the same axis. By heating with such a heater 30, the end outer periphery 6a of the tube body 6 and the socket 7a of the pipe joint 7 are heated and melted. The heating by this heater 30 is performed on the heating surfaces 22a, 23
Keep the temperature of a at 230 to 250℃ for about 20 to 30 minutes.
It can last for about seconds.

After heating by the heater 30 is completed, the heater 30 is removed from between the pipe body 6 and the pipe joint 7, and the pipe body 6 is immediately inserted into the pipe joint 7 as shown in FIG. On this occasion,
A portion of the resin 25 melted on the open end side of the socket 7a of the pipe joint 7 flows outward along the end surface 7b. Further, a portion 24 of the resin melted at the end outer periphery 6a of the tube 6 is blocked by the end surface 7b and flows out along the outer periphery of the tube 6. Further, another portion 26 of the resin melted at the socket 7a of the pipe fitting 7 is pushed by the end surface of the pipe body 6 and flows out inward in the axial direction of the pipe fitting 7.

Referring to FIG. 6, when the tube 6 is fitted into the pipe fitting 7 so that the end surface 8a of the clamp member 8 has a distance 11 between the end surface 7b of the pipe fitting 7, the clamp member 8 It is fixed to the outer periphery of the pipe body 6 at a position where a predetermined insertion length l2 into the pipe joint 7 is secured. The distance l1 is equal to the thickness of the molten resin flowing out onto the end surface 7b of the pipe joint 7 during the fusion operation.

When the pipe body 6 is fitted into the pipe joint 7, the end face 7b of the pipe joint 7 is removed from the end outer periphery 6a of the pipe body 6 and the socket 7a.
The molten resin that protrudes to the side is removed by the clamp member 8 when the pipe body 6 is inserted into the pipe joint 7 by a length l2.
is clamped between the end surface 8a of the pipe fitting 7 and the end surface 7b of the pipe joint 7. Moreover, the molten resin 24 protruding from the end outer periphery 6a of the tube body 6 is located closer to the radial inward side than the molten resin 25 protruding from the socket 7a of the pipe joint 7. Therefore, among the molten resin clamped between the end surface 8a and the end surface 7b of the clamp member 8, the molten resin 24 from the tube body 6 enters the recess 21 of the clamp member 8. After such a fitted state between the tube body 6 and the pipe fitting 7 is maintained for about 30 seconds, the clamp members 8 and 9 are removed from the tube body 6 and the tube fitting 7, respectively.

Referring to FIG. 7, after the fusion operation is completed,
A bead 27 is formed at the connection portion between the pipe body 6 and the pipe joint 7. When the prescribed fitting length l2 of the pipe body 6 into the pipe joint 7 is secured, an annular protrusion 28 that protrudes around the pipe body 6 is formed radially inwardly of the bead 27. . This protrusion 28 has a part 24 of the molten resin on the outer periphery 6a of the end portion of the tube body 6 in the recess 2.
It was formed by entering 1. Furthermore, if the clamp member 8 is not sufficiently fixed to the outer periphery of the tube body 6, when the tube body 6 is inserted into the pipe joint 7, the tube body 6 and the clamp member 8 may be axially relative to each other. Moving. Therefore, when the above-mentioned intervals l1 and l2 are maintained, the specified fitting length l2 of the tube body 6 is
cannot be secured. In this case, the clamp member 8
The molten resin is not sufficiently extruded between the end surface 7b of the pipe joint 7 and the bead 27 has a protrusion 28 as shown in FIG. 7 after the fusion operation is completed.
is not obtained.

Therefore, whether or not the tube body 6 and the pipe joint 7 are sufficiently fused can be easily and reliably determined by checking the shape of the bead 27.

Next, the results of experiments conducted by the inventor will be described. In this experiment, a pipe body 6 made of polyethylene with a nominal diameter of 50 mm and a pipe joint 7 were fused together. After heating the heating surfaces 22a, 23a of the heater 30 at 230 to 250° C. for about 20 seconds, the heater 30 was immediately removed and the tube 6 was inserted into the pipe joint 7. At this time, the interval l1 is 1.5 mm, and the insertion length l2 is 22 mm.
It was hot. After maintaining this fitted state for about 30 seconds to completely fuse, when the clamp member 8 is removed, the pipe body 6
A bead 27 is formed near the outer periphery of the pipe joint at the connection portion between the pipe joint 7 and the clamp member 8.
A protrusion 28 corresponding to the recess 21 was formed. Therefore, the specified insertion length l of the tube body 6
2 is secured and the pipe body 6 and pipe joint 7 are fused together,
It was confirmed that a bead 27 corresponding to the end surface of the clamp member 8 was formed.

As another embodiment of the present invention, instead of the above-mentioned clamp member 8, an annular body fixed to the outer periphery of the pipe body and having a recess on the end face on the pipe joint 7 side may be used, and another clamp member may be used to The body 6 may be held and inserted into the pipe joint 7. Furthermore, the present invention can be practiced not only in manual welding as in the embodiments described above, but also in connection with welding using a socket welder or the like.

As described above, according to the present invention, the annular body having the annular recess radially inward on the end face of the pipe fitting is inserted into the pipe body at a position having a predetermined length from the end of the pipe body. The pipe is fixed to the outer periphery and fitted into the pipe fitting by applying a predetermined pressure so that the end face of the annular body and the end face of the pipe fitting come close to each other, so that the pipe body can be inserted only the specified length. When the pipe body and the pipe joint are completely fused together after being inserted into the pipe joint, a bead having a shape corresponding to the end surface of the annular body is formed at the connection portion between the pipe body and the pipe joint. Furthermore, if the prescribed fitting length is not ensured and the fusion is incomplete, the shape of the bead does not correspond to the end surface of the annular body. Therefore, the fused state can be easily and reliably determined by simply observing the shape of the bead after the fusion operation is completed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the prior art, FIG. 2 is a sectional view of an embodiment of the present invention, FIG. 3 is a sectional view taken from the cutting plane line - in FIG. 5 is a sectional view showing a state in which the pipe body 6 is fitted into the pipe joint 7; FIG. 6 is a sectional view showing the state in which the pipe body 6 has been fitted into the pipe joint 7; FIG. 7 is a perspective view after the fusion operation is completed. 6... Pipe body, 7... Pipe joint, 8... Clamp member, 21... Recess, 27... Bead, l1... Spacing, l2... Fitting length.

Claims (1)

[Claims] 1. In an inspection method when a thermoplastic synthetic resin tube is inserted into a socket of a thermoplastic synthetic resin pipe joint and fused, a concave concentric and annular concave radially inward on the end face of the pipe joint is provided. An annular body having an annular body is fixed to the outer periphery of the tube body at a position having a predetermined length from the end of the tube body, and the end face of the annular body and the end face of the pipe joint are at a predetermined interval. The pipe body is inserted into the pipe joint until they are close to each other and fused together, and fusion is performed depending on whether the bead shape formed on the end face of the pipe joint at the time of fusion corresponds to the end face shape of the annular body. A socket fusion inspection method characterized by determining the state.