CH685835A5 - Drilling fitting sealingly connectable to medium pipeline - Google Patents

Abstract

In the inner thread of a pipe branch (4) is rotatably located a drilling tool (8) for the pipeline, fitted with a non-return valve (16), which can be opened for testing purposes by pressure applied externally through the branch. Pref. the non-return valve has a spherical plug (17), pressed by a compression spring (18) against a sealing edge (19). Alternately the valve plug may be disc-shaped. Typically the tool has at its actuating end a polygonal socket (14) with a through aperture (15) for the non-return valve coupling.

Description

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CH 685 835 A5

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description

The invention relates to a tapping fitting as described in the preamble of claim 1.

Tapping fittings for tapping pipes carrying a medium to create branch lines are known (e.g. CH-PS 503 542). The housings of the tapping fittings have a saddle part, which is sealed to the pipeline by gluing, clamping with an inserted seal or by welding using a resistance wire winding or by butt welding.

A leak test of this connection by means of a pressure of a medium - preferably air pressure - that can be applied from the pipe socket is possible before the pipe is drilled through if the pipe drill has a continuous opening. The disadvantage here is that after the pipeline has been drilled through, the medium can escape from it through the pipe tappet, the pipe slug drilled out and remaining in the pipe tappet also not ensuring a tight seal.

The object of the present invention is to provide a pipe tapping fitting of the type mentioned at the outset, which enables a leak test of the welded, clamped or adhesive connection to the pipeline before it is drilled without the medium being able to escape from the pipeline through the tapping fitting after or during drilling .

According to the invention, this object is achieved by the features of claim 1.

Particularly advantageous embodiments of the invention are characterized in the dependent claims.

The arrangement of a check valve in the drilling tool ensures that e.g. Compressed air from the outside for a tightness test of the connection between the pipeline and the tapping fitting enables the medium in the pipeline to escape from the tapping fitting when the pipeline is subsequently drilled through.

The invention is illustrated for example in the accompanying drawing and described below. Show it:

Fig. 1 shows a longitudinal section of a tapping fitting partially in view and

FIG. 2 shows a cross section from FIG. 1.

The housing 2 of the tapping fitting has a saddle part 3 comprising the pipeline 1 to be drilled, a pipe socket 4 and a branch socket 5 for a branch line. Arranged between the pipeline 1 and the saddle part 3 is a resistance wire 7 shaped into a heating mat 6, by means of which a welded connection between the pipeline 1 and the tapping fitting is established in a known manner. In the pipe socket 4, a drilling tool 8 is arranged, which has a cutting part 9 and a screw part 10 with an external thread 11. The external thread 11 engages in an internal thread 12 of the pipe socket

4. At the actuating end 13 opposite the cutting part 9, the drilling tool 8 has an internal polygon 14 with a through opening 15 and then a check valve 16.

A closing body of the check valve 16, which is designed as a ball 17 or an elongated body, is pressed by a compression spring 18 against a sealing edge 19, a medium pressure supplied from the outer end of the pipe socket 4 opening the check valve 16. The closure body can also be a disc e.g. be made of plastic, in which case the spring can be dispensed with due to its low weight.

The drilling tool 8 has on the side of the actuating end 13 on the outer circumference a sealing ring 21 arranged in a groove 20, which sealingly rests on a cylindrical inner surface 22 of the pipe socket 4.

For an additional and permanent sealing of the pipe socket 4 after the tapping process, a cover 24 provided with a seal 23 is screwed onto the end of the pipe socket 4 (see FIG. 1) or a cover 25 is welded on in a sealing manner. (see Fig. 2)

Tapping the with a pressure medium such as Pipelines exposed to gas or water and testing for leaks in the welded joint are carried out as described below:

After creating the welded connection between the tapping fitting and the pipeline by melting the plastic material by means of the melting temperature generated by the resistance wire and subsequent cooling, an annular hole is first made in the saddle part 3 and in the heating mat 6 with the drilling tool 8, the drilling tool 8 is rotated by means of a socket wrench and at the same time is moved forward by the thread. Thereafter, the drilling tool 8 is screwed back, the slug from the saddle part 3 and the heating wire disk resulting from the ring bore being still welded to the pipeline 1 and remaining there. By connecting the pipe socket 4 to a compressed air source while sealing the branch socket 5 at the same time, the pipe socket is pressurized with compressed air, the non-return valve 16 opens and the compressed air reaches the ring bore in the heating mat 6. If the weld between the saddle part 3 and the pipeline 1 is tight around this ring hole, there is no pressure drop in the compressed air supply. If the leak test is positive, the compressed air connection is removed and the pipeline 1 is drilled through using the drilling tool 8. The medium in the pipeline 1 cannot escape from the pipe socket 4, since the drilling tool 8 is sealed on the outer circumference and the inner through opening is closed by the check valve 16. This seal during and after the drilling process enables the drilling of pipelines under pressure of a gaseous or liquid medium. A perfect welded connection is also guaranteed when the pipe socket 4 is closed with the cover 25.

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is steady because the welding surfaces are not wetted by preventing the medium from flowing out.

If the saddle part 3 and the heating mat 6 already have an opening in the area of the pipe socket 4, the leak test is carried out after the welded connection has been made, since the first drilling process is omitted.

The design of the drilling tool with a check valve is also advantageous if the tapping fitting is connected to the pipeline by means of a clamping connection with a seal or an adhesive connection, since the leakage test and the drilling of the pipeline can then also be carried out as described above.

Claims (7)

Claims 1. Tapping fitting, which can be sealingly connected to a pipe carrying a medium and has a rotating drilling tool for drilling the pipe in an internal thread of a pipe socket, characterized in that the drilling tool (8) is provided with a check valve (16). 2. Tapping fitting according to claim 1, characterized in that the check valve (16) is designed to open by a test pressure that can be applied from the outside through the pipe socket (4). 3. Tapping fitting according to claim 1 or 2, characterized in that the check valve (16) has a preferably designed as a ball (17) closure body which can be pressed by means of a compression spring (18) against a sealing edge (19). 4. Tapping fitting according to claim 1 or 2, characterized in that the check valve (16) has a closure body designed as a disc. 5. Tapping fitting according to one of claims 1 to 4, characterized in that the drilling tool (8) at the actuating end (13) has an internal polygon (14) with a continuous opening (15) and the check valve (16) is then arranged. 6. Tapping fitting according to one of claims 1 to 5, characterized in that the drilling tool (8) has on the outer circumference a sealing ring (21) which bears sealingly against a cylindrical inner surface (22) of the pipe socket (4). 7. tapping fitting according to one of claims 1 to 4, characterized in that the connection of the tapping fitting with the pipeline (1) is designed as a tight weld, adhesive or clamp connection. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 3rd