GB2330634A

GB2330634A - Branch connection coupling

Info

Publication number: GB2330634A
Application number: GB9722298A
Authority: GB
Inventors: Robert William Jardine
Original assignee: Glynwed Pipe Systems Ltd
Current assignee: Glynwed Pipe Systems Ltd
Priority date: 1997-10-23
Filing date: 1997-10-23
Publication date: 1999-04-28
Also published as: GB9722298D0

Abstract

The coupling for making a branch connection to a conduit 14, comprises a body 1 through which a passage 2 extends between an inlet opening 6 and an outlet 7. A valve 10 is positioned in the passageway and is displaceable between passage closing and passage opening positions. A punch is mounted in the body 1 and displaceable between a retracted position in which a cutting tip of the punch is within the body and an extended position in which the cutting tip projects out of the body. The coupling is formed such that with the punch 12 retracted the body 1 may be secured to the conduit 14 with the inlet opening 6 facing a wall of the conduit, such that when the body is secured to a conduit with the valve 10 closed a sealed chamber is formed between the valve and the surface of the conduit wall facing the inlet opening, and such that an opening may be formed through the wall of the conduit on which the body is secured by extending the punch 12. The punch 12 is in a separate passage 4 at an angle to the passage 2 or parallel to it.

Description

COUPLING The present invention relates to a coupling for making a connection to a conduit, and in particular to such a coupling which incorporates a punch for forming an aperture in a conduit onto which a coupling has been mounted.

A fitting known as a punch tee has been widely used in the pipeline industry for many years. The known punch tee is designed to connect a lateral service pipe to the top of a steel main conduit. The tee comprises a steel body which is welded to the outside wall of the steel main conduit. An elongate hardened steel punch with a threaded cylindrical outer surface is screwed into a fine thread formed on the inside surface of a bore defined in the body. One end of the punch can be engaged by a suitable tool to enable it to be rotated relative to the body, and the other end which is adjacent the conduit has a substantially cylindrical portion defining a rim which is profiled and hardened so that as the punch is rotated relative to the body it progressively trepans a hole in the wall of the steel pipe to which the body is welded.

Once a hole has been formed, the punch is withdraw b' reversing the direction of its rotation relative to the body, leaving an opening in the steel main conduit. That opening communicates with a passageway extending through the body to either a compression socket or a weld-prepared end to receive the connecting service lateral.

The end of the bore remote from the steel main conduit is closed with a completion cap to ensure that no leakage can occur through the bore.

It is often desirable to install a shut off valve in a seivice lateral close to a main conduit to which the service lateral is coupled. With the known punch tee, this can only be achieved by providing a service valve as a separate unit which must be coupled to the punch tee. It is not possible to provide an arrangement in which the punch can be removed and replaced by a valve spindle as in most applications connections are made to'ilive"mains which are under pressure. Furthermore, the surface of the pipe around the hole formed by the punch is not suitable to act as a valve seat.

It is an object of the present invention to provide a combined punch tee and valve unit.

According to the present invention, there is provided a coupling for making a connection to a conduit, comprising a body through which a passage extends between an inlet opening and an outlet, a valve positioned in the passageway and displaceable between passage closing and passage opening positions, and a punch mounted in the body and displaceable between a retracted position in which a cutting tip of the punch is within the body and an extended position in which the cutting tip projects out of the body through the inlet opening, the coupling being formed such that with the punch retracted the body may be secured to a conduit with the inlet opening facing a wall of the conduit, such that when the body is secured to a conduit with the valve closed a sealed chamber is formed between the valve and the surface of the conduit wall facing the inlet opening, and such that an opening may be formed through the wall of the conduit on which the body is secured by extending the punch.

Preferably, the valve comprises a spindle which is rotatable relative to the body about a first pre-determined axis to displace the valve between the passage opening and passage closing positions, and the punch is rotatable relative to the body about a second pre-determined axis to displace the punch between the retracted and extended positions, the two axes being mutually inclined and extending through the inlet opening. Preferably the two axes intersect in the inlet opening. The punch may be mounted within an open-ended bore defined by the body, and means may be provided to seal the end of the bore which is remote from the inlet opening. The valve spindle may be mounted within an open-ended bore with w hitch a service pipe connection communicates, displacement of the valve to the passage-closing position obstructing communication between the inlet opening and the service pipe connection.

The coupling body may be formed such that either the first axis or the second axis is perpendicular to the surface of the conduit which faces the inlet opening when the body is mounted on the conduit.

An embodiment of the present invention will now be described, by way of example with reference to the accompanying drawing.

Referring to the drawing, a coupling body 1 defines a first bore 2 which is symmetrical about a first axis 3 and a second bore 4 which is symmetrical about a second axis 5. The two axes 3 and 5 intersect at a point which is central to an inlet opening 6. An outlet 7 is provided to which a lateral pipe may be connected.

A valve headwork assembly comprising a threaded nut 8, a valve spindle 9 and a valve member 10 is mounted in the upper end of the bore 2. Seals carried by the nut 8 ensure that no leakage can occur through the upper end of the bore 2. The valve member 10 may be displaced from the position shown in the drawing to a position in which a sealing face defined by the valve member 10 engages against and forms a seal with a seat 11 defined within the body 1. Thus the valve member 10 can be moved from the position shown in which an open passage is defined between the inlet opening 6 and the outlet 7 or a closed position in which the inlet opening 6 does not communicate with the outlet 7.

A punch 12 is received in the bore 4 and ma) be displaced from a retracted position in which it is shown in the drawing to an extended position in which it projects beyond the point of intersection between the axes 3 and 5. A completion cap 13 is shown mounted on the upper end of the bore 4 so as to prevent any leakage therethrough.

The drawing shows in full lines the mounting of the body 1 such that the axis 3 is perpendicular to and passes through the centre of a main 14. The annular lowermost portion of the body 1 defining the inlet opening 6 as shown in full lines is shaped so as to enable the body 1 to be welded in place on the main 14 in the illustrated orientation. The drawing also shows in broken lines an alternative configuration of the lowermost part of the body 1 which makes it possible to weld the body 1 to the main 14 in an orientation in which the axis 5 is perpendicular to the surface of the main and passes through the centre of the main. In both cases it will be noted that, assuming the main 14 extends in the horizontal direction, the axis 3 of the valve spindle 9 is vertical. Such an orientation of the valve operating spindle is important as generally ! the coupling will be located below ground at the bottom of an access passageway and as a result the valve operating spindle must be substantially vertical to permit operation from above ground using a suitable tool.

The punch 12 may be of standard form, as may be the valve headworks and the completion cap 13. U ith the axis 5 of the punch 12 oriented as shown in full lines in the drawing, that is with the valve stem extending vertically above the centre line of the main 14, the punch must penetrate the main wall in a direction which is not perpendicular to that wall. Tests have shown that it is feasible to penetrate steel mains given such a relative orientation of the punch axis, but it may be preferred, particularly with mains having comparatively thick walls, to arrange the punch axis 5 so that it is perpendicular to the vsall of the main 14 as shown in broken lines in the drawing. The two alternatives can be readily achieved using a single basic body component simply by appropriate machining of the annular portion of the body 1 around the inlet opening 6.

The installation of the coupling illustrated in the accompanying drawing is a relatively simply matter. Firstly the completion cap 13 and valve headwork assembly are removed from the body 1 to prevent damage to these components during welding.

The fitting is then welded to the main and, if a service pipe is to be welded to the body 1, the service pipe is welded in position If the body 1 is provided with mechanical coupling rather than relying upon welding to a service lateral the service lateral may be connected at a later stage in the procedure. A pressure test may then be applied to check the integrity of the weld and the soundness of any service lateral to which the body 1 is connected.

The valve headworks are then installed and the valve is closed. The punch is operated to penetrate the main 14 and then withdrawn so that under-pressure fluid in the main 14 enters the bores 2 and 4. The completion cap 1; is then installed to ensure no leakage of fluid can occur through the bore 4. After the customary checks, the valve may be open to admit fluid to the outlet 7.

Although in the described embodiment of the invention, the axis 3 of the valve is inclined to the axis 5 of the punch, it will be appreciated that the valve and punch could be arranged with their axes parallel but spaced apart. With such an arrangement, the assembly would be mounted with both the valve and punch axes vertical but with the punch axis located over the centre line of the main to which connection is to be made.

Claims

CLAIMS 1. A coupling for making a connection to a conduit, comprising a body through which a passage extends between an inlet opening and an outlet, a valve positioned in the passageway and displaceable between passage closing and passage opening positions, and a punch mounted in the body and displaceable between a retracted position in which a cutting tip of the punch is within the body and an extended position in which the cutting tip projects out of the body through the inlet opening, the coupling being formed such that with the punch retracted the body may be secured to a conduit with the inlet opening facing a wall of the conduit, such that when the body is secured to a conduit with the valve closed a sealed chamber is formed between the valve and the surface of the conduit wall facing the inlet opening, and such that an opening may be formed through the wall of the conduit on which the body is secured by extending the punch.
2. A coupling according to claim 1, wherein the valve comprises a spindle which is rotatable relative to the body about a first pre-determined axis to displace the valve between the passage opening and passage closing positions, and the punch is rotatable relative to the body about a second pre-determined axis to displace the punch between the retracted and extended positions, the two axes being mutually v inclined and extending through the inlet opening.
3. A coupling according to claim 9, wherein the two axes intersect in the inlet opening.
4. A coupling according to claim 2 or 3, wherein the body is formed such that when mounted on a conduit the first axis is perpendicular to the conduit surface.
5. A coupling according to claim 2 or 3, wherein the body is formed such that when mounted on a conduit the second axis is perpendicular to the conduit surface.
6. A coupling according to any preceding claim, wherein the punch is mounted within an open-ended bore defined by the body, and means are provided to seal the end of the bore remote from the inlet opening.
7. A coupling according to any preceding claims, wherein the valve spindle is mounted within an open-ended bore defined by The body and with which a service lateral connection communicates, displacement of the valve to the passage-closing position obstructing communication between the inlet opening and the service pipe connection.
8. A coupling for making a connection to a conduit substantially as hereinbefore described with reference to the accompanvil1g drawing.