GB2334316A

GB2334316A - Pipe connection

Info

Publication number: GB2334316A
Application number: GB9803267A
Authority: GB
Inventors: Park Sil-Sang
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-01-01
Filing date: 1998-02-16
Publication date: 1999-08-18
Also published as: ZA981411B; GB9803267D0; AU693065B1; CA2223976A1; ES2160438A1; ES2160438B1; NL1008375C2; JPH11230439A

Abstract

A pipe connector connects first and second pipe ends A,B, one pipe end having a circumferential groove 11 on its extemal surface spaced from the end of said pipe, the connector having a body 1 which screws into the other pipe and a nut 5 which engages therewith and presses in a ductile ring 4, which may be separate or part of the body 1, to force part of the ring into the pipe groove 11. Friction on the pipe and thus easier tightening and greater pressure to be applied to force the ductile ring into the groove 11 is provided by pressure projections on an internal surface of nut 5 and/or on the ring 4. Where the ring 4 is separate from the body 1, projections may be provided in the latter. The ring 1 may comprise two parts, or be part or all axially split for reducing its circumference as it is tightened. Also disclosed are tools for making the groove on the pipe end.

Description

PIPE CONNECTION The present invention relates to pipe connections and more particularly to a pipe connector which when tightenend forces a ductile ring within the connector into a reentrant groove near one end of the pipe so as to provide a better connection between the connector and the pipe.

In known pipe connectors, one end of the pipe is inserted into the connector with the ductile ring sliding over the outside of the pipe end.

The connector includes a tightening nut, which, when rotated, puts pressure on the ductile ring clamping it tightly over the pipe end.

However, this known system has a large surface area of contact between the interior surface of the tightening nut and the exterior surface of the ductile ring which increases friction as the tightening nut is turned to put pressure on the ductile ring within it. The increased friction means decreased efficiency of clamping, resulting in greater difficulty of installation and reduced pressure on the ductile ring. The lower pressure on the ductile ring in turn means that the connection is not as firm and leak proof as it might otherwise be. Worse still, the increased chance of leakage presented by this problem is not likely to manifest itself until a considerable period of time has elapsed after completion of the coupling.

Finally, there is only a simple toroidal contact between the interior of the ductile ring and the exterior of the pipe end. In the event of later tension forces on the pipes, the connection is a weak point which is likely to move or warp under the tension force. The result is the likelihood of leakage which is undesirable.

It is therefore one object of the present invention to provide a pipe connector which maintains a tighter connection between two pipe ends.

It is another object of the present invention to provide a pipe connector which is less prone to leakage long after installation.

It is another object of the present invention to provide a pipe connector which is capable of maintaining a tight, leakproof seal despite external tensions which would tend to warp the pipe connection.

It is another object of the present invention to provide a pipe connector which reduces friction during tightening thereby making it easier to tighten the connector.

According to the invention, there is provided a pipe connector for connecting first and second pipe ends together, one of said pipe ends having a circumferential groove on its external surface spaced from said one end, the connector comprising a tightening nut coaxially fitted to the exterior of said first pipe end so as to rotate relative thereto, a body screw coaxially fitted to said second pipe end and adapted to be engaged by the tightening nut, a ductile ring disposed within said tightening nut to surround said first pipe end when the body screw engages therewith, the arrangement being such that when said nut is tightened, a portion of the ductile ring is forced into said circumferential reentrant groove to provide a leakproof joint between the pipe ends.

Preferably the groove is reentrant and provided on the pipe at a predetermined distance W from the end thereof acted on by the tightening nut which applies sufficient pressure to the ductile ring to drive a lip of the ductile ring into the reentrant groove. The nut preferably includes pressure projections on its interior surface which act on the outer surface of the ductile ring to force its extreme end into the reentrant groove.

The increased pressure applied by the improved tightening nut is itself an asset in preventing leakage at the connection between the pipe ends thereby maintaining a strong connection against future leakage.

The part of the ductile ring which projects into the reentrant groove provides greatly increased strength to the connection between the pipes.

In particular, the joint remains stronger under conditions of tension (such as support of a weight) thus increasing protection against leaks, which is most useful long after the pipes have been installed.

The reduced friction of the tightening nut also aids installation of the pipe connection, thus reducing time, energy and cost of the pipe connection.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view illustrating a pipe connection using a connector of the present invention; Figure 2 is a partially sectional view illustrating the pipe connection shown in Figure 1; Figure 3 is a sectional view taken along line C-C of Figure 2; Figure 4 is an exploded perspective view illustrating a pipe connection using an alternative embodiment of pipe connector; Figure 5 is a partial sectional view illustrating the pipe connection shown in Figure 4; Figure 6 is a perspective view of a ductile ring with pressure projections formed thereon rather than on the tightening nut; Figure 7 is a sectional view of the tightening nut shown in Figure 1; Figure 8 is a sectional view of an alternative tightening nut; Figure 9 is an exploded perspective view of a still further tightening nut; Figure 10 is a partial sectional view illustrating one form of tool for use with connectors of the invention; Figure 11 is a partial sectional view illustrating an alternative form of working tool; Figure 12 is a partial sectional view illustrating a connector of the invention fitted to a ribbed type of pipe; Figure 13 is a perspective view illustrating a two-piece ductile ring; Figure 14 is an exploded perspective view of an alternative form of twopiece ductile ring; Figure 15 is a cross sectional view illustrating the ductile ring of Figure 13 in a pipe connector; Figure 16 is a perspective view illustrating a ductile ring with pressure projections; Figure 17 is a perspective view illustrating an alternative ductile ring; and Figure 18 is a sectional view illustrating the embodiment of Figure 16 in a pipe connector.

Referring now to the drawings, there is shown in Figure 1, copper pipe ends A and B connected by means of a connector of the invention.

Screw body 1 has pipe end engaging threads 2, threads 3 and ductile ring 4. Ductile ring 4 is a thin ring of material which may be part of the body 1, as shown in this embodiment, or it may be a separate component, as shown in an alternative embodiment described hereafter. Ductile ring 4 possess sufficient ductility to deform slightly when an external pressure is applied thereto, and may have a variety of cross sections, as will also be described hereafter. In the illustrated embodiment, the ductile ring 4 has a thin lip 4a to allow greater ductility at that point, said lip being an extension of body 1. In other embodiments however, the entire ductile ring 4, or sections thereof may be made to be thin, or otherwise made especially ductile.

Tightening nut 5 has a screw portion 6 which engages with the threads 3 of the body . 1. Tightening nut 5 also has an inclined surface 7 to match the external surface 4b of ductile ring 4. Disposed upon the inclined surface 7 are a plurality of pressure projections 8 which bear upon the external surface 4b of ductile ring 4, applying increasing pressure to it as the nut 5 is tightened and screwed onto body 1. However, the entire inclined surface 7 is not allowed to contact the ductile ring 4 until it is deformed in the final stages of tightening the nut 5. In known systems, the large contact area between the interior of nut 5 and the exterior of ductile ring 4 increases friction, making tightening more difficult. A packing ring 10 is disposed within ductile ring 4 in this embodiment.

Reentrant groove 11 is provided on the exterior of pipe end A and is disposed at a distance W from the end of the pipe. Reentrant groove 11, in this embodiment, spans the thin lip 4a of the ductile ring 4 such that as the nut 5 is screwed onto body screw 1, the pressure projections 8 bear on ductile ring 4 forcing a portion thereof, in this embodiment, the thin lip 4a, to enter the reentrant groove. This locks the two pipe ends A and B together, making them better able to withstand tensional forces.

Figure 2 is a partial sectional view illustrating a pipe connected by means of the connector shown in Figure 1, the thin lip 4a of ductile ring 4 being shown pressed into reentrant groove 11.

Figure 3 is a sectional view taking along line C-C of Figure 2, showing the pressure projections 8 bearing on the exterior surface 4b of the ductile ring 4 but leaving a slight gap between the interior of nut 5 and the exterior of the ductile ring 4.

Figure 4 is an exploded perspective view illustrating an alternative embodiment of pipe connector having a different type of ductile ring 12 which is separate from the body 1. In this embodiment, the pressure projections 8 are disposed within the interior surface of body 1.

Otherwise, this embodiment is not significantly different from the previous one. Note that nut 5 does not have pressure projections in it but it can if desired.

Figure 5 is a partial sectional view illustrating a pipe connected by means of the connector of the invention shown in Figure 4, showing a part of ductile ring 12 forced into the reentrant groove 11.

Figure 6 is a perspective view of an alternative embodiment in which pressure projections 8 are provided on the ductile ring 12 rather than on the tightening nut 5.

Figure 7 is a sectional view of the tightening nut 5 shown in Figure 1.

Figure 8 is a sectional view of an alternative embodiment in which the pressure projections 8 are arranged at angle to the longitudinal axis of the nut 5.

Figure 9 is an exploded perspective view of an alternative embodiment with the pressure projections 8 provided on the body 1 rather than on the tightening nut 5. In this embodiment, the body 1 also has a core pipe la inside it.

Figure 10 is a partial sectional view illustrating tool 13 which has a roller cutter 13a and a molding roller 13b thereon separated from each other by the predetermined distance W. As the working tool 13 is rotated over a length of pipe, the cutter 13a cuts the pipe while the molding roller 13b forms the reentrant groove 11.

Figure 11 is a partial sectional view illustrating an alternative embodiment of a working tool 13 capable of forming a reentrant groove 11 on both sides of a cut in a length of pipe.

Figure 12 is a partial sectional view illustrating an alternative embodiment of connector for fitting to a flexible or spiral type of pipe.

Figure 13 is a perspective view illustrating another embodiment of the invention in which the ductile ring 12 has a locking projection 12d on its inside surface which fits in reentrant groove 11 when the connector is installed on a pipe end. Ductile ring 12 also has a small gap 12b formed in it and it will be noted that it has a different cross section, one with a thinner projecting portion which is used in conjunction with packing ring 10 to provide a better seal.

Figure 14 shows a similar embodiment in which the ductile ring 12 is mated to a second ring 12a which fits within ductile ring 12 to provide a tighter closure after installation. The two rings fit together to form a single unit. Ductile ring 12 also has a narrow connection 12c bridging the small gap 12b. When ductile ring 12 is used with a tightening nut 5 such as is shown in Figure 1, the narrow connection 12c acts to slide the pressure projections 8 across the small gap 12b thereby preventing the two units from locking together.

In this embodiment, when the tightening nut 5 is sufficiently tight, the narrow connection 12c breaks, narrowing the small gap 12b and providing a tighter seal. The small gap 12b may be a narrowing of said ductile ring, as shown in Figure 14 or can comprise at least one hole leaving a plurality of narrow connections 12c, or it may span the entire ductile ring, leaving no narrow connection 12c.

Note that in this embodiment, the packing seal 10 and the second ring 12a cooperate to form a tight closure. In this embodiment, packing seal 10 is designed to have a large width, so as to cover the surfaces of second ring 12a. This embodiment has the advantage of being usable on existing pipe connections without modification or change.

Figure 15 is cross sectional view illustrating an application of the ductile ring embodiment of Figure 13, and showing how the packing seal 10 and the second ring 12a portion of the ductile ring 12 act together to form a tight seal.

Figure 16 is a perspective view illustrating an alternative embodiment of the invention having an additional circumferential pressure projection 8a on the external surface 4b of ductile ring 4. This acts to reduce friction by reducing the amount of surface contact area.

Figure 17 is a perspective view illustrating a still further embodiment in which the circumferential pressure projections 8b are not circumferentially continuous.

Figure 18 is a sectional view illustrating an application of the embodiment of Figure 16.

It should be noted that the circumferential pressure projections 8a and 8b could be, as shown, on the ductile ring 4, or on ductile ring 12, or on the inclined surface 7 of tightening nut 5.

Claims

Claims 1. 1. A pipe connector for connecting first and second pipe ends together, one of said pipe ends having a circumferential groove on its external surface spaced from said one end, the connector comprising a tightening nut coaxially fitted to the exterior of said first pipe end so as to rotate relative thereto, a body screw coaxially fitted to said second pipe end and adapted to be engaged by the tightening nut, a ductile ring disposed within said tightening nut to surround said first pipe end when the body screw engages therewith, the arrangement being such that when said nut is tightened a portion of the ductile ring is forced into said circumferential reentrant groove to provide a leakproof joint between the pipe ends.
2. A pipe connector according to claim 1 further comprising a plurality of pressure projections situated on the interior surface of said tightening nut to apply pressure to said ductile ring as said nut is tightened.
3. A pipe connector according to claim 1 further comprising a plurality of pressure projections situated upon the interior surface of said body screw to apply pressure to said ductile ring as said nut is tightened.
4. A pipe connector according to claim 1 further comprising a plurality of pressure projections situated upon the exterior surface of said ductile ring to apply pressure to said ductile ring as said nut is tightened.
5. A pipe connector according to claim 2 wherein said pressure projections are situated at an angle relative to the longitudinal axis of the first and second pipe ends.
6. A pipe connector according to any preceding claim wherein an auxiliary ring is provided within said ductile ring to form a single unitary ring structure with a thin portion of said auxiliary ring projecting axially along the circumference of said ductile ring and a packing seal disposed so as to engage said projecting portion of said auxiliary ring when said nut is tightened.
7. A pipe connector according to claim 1 wherein said ductile ring includes a circumferential locking projection on the interior surface thereof arranged to engage said reentrant groove.
8. A pipe connector according to claim 2 wherein said ductile ring has a gap therein to allow the circumference thereof to decrease as the nut is tightened.
9. A pipe connector according to claim 8 wherein a narrow connection spans the gap in the ductile ring to allow the pressure projections to slide across the gap without becoming lodged.
10. A pipe connector substantially as herein described with reference to the accompanying drawings.
11. A pipe connection between first and second pipe ends substantially as herein described with reference to the accompanying drawings.