A PIPE COUPLING FOR CONNECTING A BRANCH PIPE TO A FEED PIPE

Abstract: A pipe coupling for connecting a branch pipe to a feed pipe (1) comprising first and second coupling parts (2, 3) sealingly embracing the feed pipe. A cylindrical guide passageway (5) is formed in said second coupling part and a cylindrical piston (6) is sealingly inserted in the guide passageway. The piston is at its inner end (7) provided with a knife-shaped cutting means (8) and is formed with a channel (9) for flow communication between the feed pipe and a branch pipe connection (10) in said second coupling part. In the assembled position of the coupling parts a portion of the feed pipe projects in radial direction into the guide passageway and the cutting means of the piston is positioned laterally of the projecting portion of the feed pipe. Said cutting means is, upon rotation of the piston, without a translatoric movement thereof, arranged to cut a hole in the feed pipe.

Description: A PIPE COUPLING FOR CONNECTING A BRANCH PIPE TO A FEED PIPE FIELD OF THE INVENTION This invention relates to a pipe coupling for connecting a branch pipe to a feed pipe without the necessity of cutting down or stopping the flow in the feed pipe. DESCRIPTION OF THE PRIOR ART A pipe coupling of the above mentioned kind is previous¬ ly disclosed in Swedish Patent No. 7910060-8 and comprises coupling parts sealingly embracing the feed pipe, a cylind¬ rical guide passage-way formed in the coupling parts, a cylindrical piston sealingly inserted in the guide passage¬ way, said piston being at its inner end provided with a knife-shaped cutting-up means and formed with a passage¬ way for flow connection between the feed pipe and the branch pipe connected to the coupling part. In the assembled position of the coupling parts a portion of the feed pipe projects in radial direction into the guide passage-way and knife-shaped means of the piston is off¬ set to said projecting portion of the feed pipe and is arranged to cut up a hole in the feed. pipe upon rotation of the piston without translatoric movement. In the known pipe coupling the edge of the knife-shaped means is arranged to extend longidudinally relative to said piston from the point at least up to a level with the mantle surface of said feed pipe positioned furthest into the guide passage-way and the piston has an axis directed axially relative to the feed pipe in order to be able to cut up, upon said rotation, two holes posi¬ tioned along the feed pipe at a distance from each other with an intermediate bridge. The advantage of the known pipe coupling is that the flow area of the holes can be made at least as large as the cross section area of the feed pipe. A disadvantage of the known pipe coupling is, however, that is has proved not to manage feed pipes of harder materials than copper. SUMMARY OF THE INVENTION The pipe coupling according to the invention can be used both for thin-walled steel tubes and for copper tubes. The characteristics of the invention are that the knife- shaped means has an edge positioned only in the transverse plane of said piston with an extension along substantial¬ ly radial direction of the piston and that the axis of the piston is directed transversally relative to the axis of the feed tube with a displacement relative to the centre of the feed pipe. In a preferred embodiment of the invention said edge is provided with a point positioned inwardly relative to the periphery of said piston and the axis of the piston is directed along substantially tangential direction relative to the feed pipe. DESCRIPTION OF THE DRAWINGS The invention is in the following described with reference to the accompanied drawings in which Fig. 1 shows a front view of a pipe coupling in a preferred embodiment connec¬ ted to a feed ip wherein in elucidating purpose a piston included in the pipe coupling is omitted, Fig. 2 is a cross section of the pipe coupling accor¬ ding to Fig. 1 and furthermore shows a cross section and a side view of the piston incorporated in the pipe coupling. Fig. 3 is a view from below showing a cutting means of the piston, and Fig. 4 is a view from above showing the pipe coupling. PREFERRED EMBODIMENT As appears from the embodiment shown in Figs. 1-4 the pipe coupling according to the invention consists of two coupling parts 2 and 3 sealingly embracing a feed pipe 1. The coupling parts 2 and 3 are bv screws 4 fixed relative each other and embrace the feed piDe 1. One of the coupling parts 3 is provided with a cylindrical guide passage-way 5 for a likewise cylindrical piston 6. The piston 6 is at its inner end 7 provided with a knife-shaped cutting means 8 and is formed with a channel 9 for flow communi¬ cation between the feed pipe 1 and the connection 10 pro¬ jecting from the coupling part 3 for a branch pipe (not shown) . In the assembled position of the coupling parts 2 and 3 a portion of the feed pipe projects in radial direction into the guide passage-way 5. Moreover, the cutting means 8 of the piston 6 is positioned laterally of the projec¬ ting portion of the feed pipe 1 and is upon rotation of the piston 6 without translatoric movement thereof arranged to cut up a hole 11 in the feed pipe 1. The knife-shaped cutting means 8 has according to the invention an edge 12 positioned only in a transverse plane of the piston 6 with an extension along substantially radial direction thereof and the axis of the piston 6 is directed transversally relative to the axis of the feed pipe 1 with a displacement relative to the centre of the feed pipe. In a preferred embodiment of the invention, the edge 12 is provided with a point 13 positioned inwardly relative to the periphery of the piston 6 and the axis of the piston is directed along substantially tangential direction relative to the feed pipe 1. By for instance a- wrenchor another appropriate tool the piston 6 is arranged to be rotated one revolution clock¬ wise for cutting up the hole 11 in the feed pipe 1. The inner end 7 * of the piston 6 is in the preferred embodiment in a manner known per se through the Swedish patent No. 7910060-8 plough-shaped for up-folding a material 14 cut out from the feed pipe 1 into the guide passage-way 5. Besides the fact that cut-out material 14 accordingly does not follow a flow in the pipe coupling, nor by fol¬ ding downwardly into the flow disturbs the flow, an effec¬ tive fastening of the pipe coupling in its position of the feed pipe 1 is established. After the cutting the piston 6 is used as valve body for controlling the flow through the connection 10. The pis¬ ton 6 is for this purpose provided with a sealing 15 which after rotation half a revolution closes the opening between the channel 9 and the connection 10. Moreover, the piston 6 is provided with a sealing ring 16.

Claims: CLAIMS ; 1. A pipe coupling for connecting a branch pipe to a feed pipe (1), comprising first and second coupling parts (2, 3) sealingly embracing the feed pipe, a cylindrical guide passage-way (5) formed in said second coupling part, a cylindrical piston (6) sealingly inserted in the guide passage-way, which piston at its inner end (7) is provided with a knife-shaped cutting means (8) and is formed with a channel (9) for flow communication between the feed pipe and a branch pipe connection (10) in said second coupling part, wherein in the assembled position for the coupling parts a portion of the feed pipe projects in radial direction into the guide passage-way and the knife- shaped cutting means of the piston is positioned laterally of the projecting portion of the feed pipe and is arranged, upon rotation of the piston without a translatoric movemen thereof, to cut a hole in the feed pipe, c h a r a c t e ¬ r i z e d in that the knife-shaped cutting means has an edge (12) positioned only in a transverse plane relative to the axis of the piston with an extension along substan¬ tially radial direction of the piston and that the axis of the piston is directed transversely relative to the feed pipe with a displacement relative to the axis of the feed pipe. 2. A pipe coupling according to claim 1, c h a r a c ¬ t e r i z e d in that said edge is provided with a point (13) positioned inwardly relative to the periphery of said piston and that the axis of the piston is directed along substantially tangential direction relative to the feed pipe.

Inventors: ROGSTADIUS IVAN, ROGSTADIUS, IVAN
Applicants: ROGSTADIUS IVAN, ROGSTADIUS, IVAN
Application year: 1987
Main classification: F16L41
IPC codes: F16L41