WO2011001376A1

WO2011001376A1 - Pipe coupling

Info

Publication number: WO2011001376A1
Application number: PCT/IB2010/052965
Authority: WO
Inventors: Yigaal Moshe Egozi
Original assignee: Plasson Ltd
Priority date: 2009-07-02
Filing date: 2010-06-29
Publication date: 2011-01-06
Also published as: GB2471502A; GB0911443D0; GB2471502B

Abstract

A compression-type pipe coupling for coupling a pipe (3) to another fixture, the. coupling comprising a coupling body (16) including a pipe (P) receiving bore; a tightening element (10) including a pipe receiving bore (39), which is co-operable with a connection mechanism (28) of the coupling body (16); and an internal sloping surface (30) tapering toward a distal end (27) of the tightening element (10); a deformable grip ring (12) including: an inner pipe- gripping surface (22); an outer surface (33) generally corresponding to the internal sloping surface (30) of the tightening element (10) and disposed adjacent thereto, and a seal interface surface; and a seal (14) which is adjacent the pipe (P) when the pipe (P) is coupled, wherein when the pipe (P) is coupled, both the seal (14) and grip ring (12) engage with the sloping surface (30).

Description

PIPE COUPLING

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims priority from patent application GB 0911443.0, entitled "Pipe Coupling" and filed on 2 My 2009.

FIELD OF THE INVENTION

The present invention relates to a compression-type pipe coupling, in particular a universal or large compression-type pipe coupling.

BACKGROUND OF THE INVENTION

Pipe couplings typically are manufactured to receive a pipe having a particular size that must be securely held. In cases where the pipe is intended to transport a fluid under high pressure, the coupling must provide a good seal to prevent leakage. For these reasons, pipe couplings are typically constructed in a wide range of sizes and designs to accommodate pipes of various diameters and materials.

Such couplings typically comprise a coupling body and a securing or tightening element (e.g. nut) having corresponding threads; a grip ring with internal barbed ribs to grip the outside surface of the pipe; and a compression sleeve and a resilient sealing gasket (e.g. an O-ring). To ensure proper sealing, typically the gasket or O-ring is dimensioned so that there is some contact with the pipe when the pipe is inserted into the coupling. This is not commonly an issue with small pipes, however for larger pipes the resistance resulting from pressing the pipe through the gasket requires considerable force which can make assembly difficult.

Universal-type pipe couplings are adapted to receive pipes having a relatively wide range of outer diameters. Here, the seal (i.e. gasket, O-ring, etc.) typically has an inner diameter larger than the outer diameter of the pipe; or if not, the seal is stretched by the pipe during insertion of the pipe. A practical problem typically encountered with universal and/or large pipe couplings is that when the nut has been only partially tightened it radially presses on the grip ring causing the inwardly directed barbed ribs to engage the outer surface of the pipe. Further tightening of the nut then results in the pipe being urged in the direction of the nut's movement along its longitudinal axis due to the force exerted on the pipe by the barbed projections. However, because the pipe is typically inserted into the coupling until its end abuts against an abutment surface or stopper element so as to properly position the pipe, there is no additional room for the pipe to move. As the nut is further tightened, the pipe is subject to forces that may cause deformation and changes in the flow of the fluid through the pipe. Further, the rotation of the nut requires more and more torque to the point where further tightening is essentially impossible and the nut is locked and appropriate sealing contact on the seal is not achieved, and at times, it may be incorrectly assumed that the nut is fully tightened due to the resistive forces of pipe, resulting in a leaky coupling.

Examples of universal and/or large pipe couplings are disclosed in US 6,702,336 (Chelchowski, et al.), US 6,464,267 (Egozi) and US 6,378,915 (Katz).

To help provide for proper sealing and pipe gripping, US 6,702,336 and US 6,464,267 disclose designs that provide a stop indication for appropriate positioning of the pipe while allowing the pipe to further enter the coupling after the grip ring has gripped the pipe, upon final tightening of the nut; and US 6,378,915 provides a specially designed grip ring, compression sleeve and sealing ring combination.

US 6,069,361 (MWM Distributors) also relates to a plumbing compression fitting for connecting the ends of pipes; however, for a specific diameter of pipe.

An object of the present invention is to provide a pipe coupling having at least one advantage making it particularly useful as a universal-type and/or large pipe coupling, as will be described below. SUMMARY OF THE INVENTION

According to one aspect, the present invention provides a pipe coupling of the compression type for coupling a pipe to another fixture, the coupling comprising: a coupling body including a pipe receiving bore; a tightening element including: a pipe receiving bore, which is co-operable with a connection mechanism of the coupling body and an internal sloping surface tapering toward a distal end of the tightening element; a deformable grip ring including: an inner pipe-gripping surface, an outer surface generally corresponding to the internal sloping surface of the tightening element and disposed adjacent thereto, and a seal interface surface; and a seal which is adjacent the pipe when the pipe is coupled, wherein when the pipe is coupled, both the seal and grip ring engage with the sloping surface.

The term "tightening element" herein the specification and claims, should be understood in its broadest sense including, for example, that the tightening element can be clamped or pushed onto the coupling body; and that the generic function of the tightening element is that it moves axially with respect to the coupling body. The tightening element can also be constituted by a more common component such as a nut or the like.

This construction permits the pipe coupling to be manufactured according to a standard size, or a relatively small number of standard sizes, each standard size being able to accommodate a relatively wide range of pipe diameters. Such a feature reduces the need to stock a large number of parts for different pipe sizes, and reduces the costs of tooling, production, maintenance, repair and inventory. Further, the end user need not know the exact dimension (or type) of the pipe. Also, large pipes are easily coupled in that there is no resistance from a seal dimensioned for a particular pipe size; there is a greater manufacturing tolerance and so the pipe coupling is easier to manufacture, typically resulting in less scrap and labor cost savings; the pipe does not need to (and does not) move forward during tightening. The latter feature is particularly important when used in a so-called sliding or repair coupling as in such a case the coupling does not include a pipe stop because sliding is typically required to effect the repair (pipe coupling replacement). Also, in the case of a repair where the pipes to be connected are anchored, the present pipe coupling design is advantageous as the pipes need not move forward (and would not due to the anchoring) in order to sealingly connect the pipes. However, the pipe coupling design does not preclude the use/inclusion of a pipe abutment member.

Furthermore, there is no need for a compression sleeve element, as the tightening element acts as a compression element. This is in contrast to typical compression-type pipe couplings that include a compression sleeve element, usually disposed between the grip ring and the seal/O-ring. Regardless, the present pipe coupling design does not preclude the use (inclusion) of a compression sleeve element.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood upon reading of the following detailed description of non-limiting exemplary embodiments thereof, with reference to the following drawings, in which:

Fig. 1 is an exploded perspective view of an embodiment of a pipe coupling of the present invention;

Figs. 2-4 are sectional views of the embodiment of the pipe coupling of FIG. 1 at progressive stages of tightening/assembling thereof, namely a slightly tightened situation, a more tightened situation and a fully tightened situation, respectively;

Fig. 5 is a sectional view of the embodiment of the pipe coupling of FIG. 1 illustrating a situation with a high pressure fluid in the pipe; and

Fig. 6 is a sectional view of another embodiment the pipe coupling of the present invention, illustrating an alternate seal/gasket location.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The following detailed description of the invention refers to the accompanying drawings. Dimensions of components and features shown in the figures are chosen for convenience or clarity of presentation and are not necessarily shown to scale. Wherever possible, the same reference numbers are used throughout the drawings and the following description to refer to the same and like parts.

FIG. 1 shows an exploded perspective view of a pipe coupling for connecting a pipe P (FIGS. 2-4), to be inserted into the coupling, to another pipe(s) or other plumbing component. The coupling includes a tightening element depicted, for example, by a nut 10; a radially flexible or deformable gripping member such as grip ring 12; a seal or gasket depicted, for example, by an O-ring 14; and a coupling body 16. In the presently illustrated embodiment, the coupling further comprises an optional additional seal or gasket depicted by O-ring 18 which is typically disposed in a correspondingly dimensioned groove 20 in coupling body 16. According to an alternative embodiment, groove 20 is disposed in nut 10, with gasket 18 in the groove.

Grip ring 12 is designed to fit within nut 10 and surround and grip pipe P for which purpose the grip ring has an inner pipe-gripping surface typically including a plurality of radially inwardly directed spaced-apart annular barbs 22; however, the grip ring could alternatively include any appropriate pipe-gripping surface or component. Upon coupling, grip ring 12 is radially pressed so that barbs 22 engage pipe P when the grip ring is pressed onto the outer surface of the pipe, as will be described below. Regardless, grip ring 12 need not have barbs; rather the grip ring can grip the pipe P via a friction or pressure interaction or the like.

Nut 10 has, at a proximal end 25 thereof, a connection mechanism, for example by threads 26 (FIGS. 2-4), which are engagable with a corresponding connection mechanism of coupling body 16, depicted by threads 28. Typically, a pipe coupling comprises a connection mechanism, however, in some circumstances, the coupling is connected using an associated tool (not shown) and so no such connection mechanism is required. At its distal end 27, nut 10 has an internal sloping surface 30, which is illustrated in FIGS. 2-5 as being conically tapered. However, according to some embodiments the internal sloping surface slopes in a curved manner, or can be in any form or shape, including having a step; thus sloping surface 30 is generally defined wherein diameter D is greater than diameter d (shown in FIG. 4); where diameter d is at a point of sloping surface 30 that is closer to distal end 27 of nut 10 than diameter D, and this definition should be understood as such herein the specification and claims. Nut 10 also has a pipe receiving bore 32 through which pipe P enters during the coupling procedure. Nut 10 typically has some type of hand or tool gripping feature, for example, circumferentially arranged external ribs (not shown) to assist with tightening the nut.

As can be understood, O-ring 14 is disposed within the confines of nut 10. Moreover, O-ring 14 is disposed within the confines of nut 10 having internal sloping surface 30. As a result, when the pipe coupling is tightened on pipe P, i.e. nut 10 is tightened, the O-ring is pressed so that it extends radially inward toward the pipe. To help grip ring 12 slidingly interface with internal sloping surface 30, the grip ring typically comprises a sloped or angled outer surface 33.

O-ring 14 is typically at least partially made of an elastic material, for example, natural or artificial rubber, or the like, so that it is deformable in the radial and/or longitudinal directions. In the present embodiment, O-ring 14 is disposed between a forward surface 34 of coupling body 16 and rear surface 36 of grip ring 12, and is sandwiched between those surfaces when the coupling is assembled (FIGS 2-4), and resides within the confines of nut 10.

According to other embodiments, O-ring 14 is disposed forward of grip ring 12 within the confines of nut 10, whereby the O-ring interfaces with a forward surface 37 of grip ring 12 when the coupling is assembled, and resides within the confines of nut 10, as will be described below.

As mentioned above, coupling body 16 has a connection mechanism such as threads 28 that correspond to threads 26 of nut 10. Coupling body 16 also includes a pipe receiving space or bore 39 and a pipe stopping element or abutment element, for example, annular shoulder 38 to provide a stopper indication so that the assembler of the coupling knows how far to insert pipe P. An abutment element such as annular shoulder 38 is not specifically required, and according to alternative embodiments, coupling body 16 does not comprise an abutment element.

Assembly:

The pipe coupling can be assembled by positioning the aforementioned components as understood from FIG. 1; and then partially screwing nut 10 onto body 16, as shown in FIG. 2. Pipe P is then inserted into bore 32 of nut 10 until the end of the pipe interfaces with annular shoulder 38. As can be observed in FIG. 2, O-ring 14 is not yet been pressed and the barbs 22 of grip ring 12 have not yet interfaced with the outer surface of pipe P.

In one scenario, upon initial tightening of nut 10 onto body 16, (FIG. 3), O-ring

14 comes in contact with surface 34 of body 16 and surface 34 prevents further axial movement of the O-ring. As O-ring 14 is made of a pliant and resilient material, the O- ring expands/deforms in the radial direction, both inwardly and outwardly. However, when O-ring 14 abuts up against internal sloping surface 30 of nut 10, it cannot expand in the outward radial direction rather it only expands inwardly to interface with the outer surface of pipe P to form a seal.

In the particular example shown, O-ring 14, and the components with which the O-ring interfaces, are dimensioned such that with minimal tightening of nut 10, or upon initial tightening thereof, the O-ring interfaces with internal sloping surface 30 of the nut; and, the O-ring interfaces with grip ring 12, at the ring's rear surface 36. This situation can be termed a generally simultaneous (or nearly simultaneous) sealing and initiation of pipe gripping.

Depending upon the outer diameter of pipe P and the dimensions of O-ring 14, grip ring 12 and nut 10 at its internal sloping surface 30, there are possible variations of what occurs during tightening of the nut; which include:

1) O-ring 14 first interfaces internal sloping surface 30 and then the O-ring interfaces with grip ring 12. Further tightening of nut 10 causes O-ring 14 to form a seal against the nut's internal sloping surface 30 and the pipe P. Continued tightening urges the O-ring axially thereby pushing grip ring 12 axially forward into narrowing internal sloping surface 30 of nut 10, causing the grip ring to be pressed radially inward whereby barbs 22 of the grip ring will grip pipe P; and

2) O-ring 14 first interfaces with grip ring 12, pushing the grip ring forward into the narrowing internal sloping surface 30 of nut 10. Further tightening of nut 10 causes the grip ring to be pressed radially inward whereby barbs 22 of the grip ring grip pipe P. Meanwhile, O-ring 14 is also moved axially forward and is pressed radially, both inwardly and outwardly, to eventually form a seal against the nut's internal sloping surface 30 and the pipe P. Again, the timing of the sealing and gripping depends on the particular dimensions of the components involved.

As can be understood, with the pipe coupling of the present invention, a proper coupling and seal can thus be attained under a variety of scenarios (i.e. combinations of dimensions) thereby tending to ease manufacturing tolerance of the components and typically allowing the use of a relatively wide range of pipe diameters.

Assuming the pipe P and the tightening element (nut 10) are completely rigid, it is preferable that upon tightening the coupling, that the seal (O-ring 14) contacts the pipe prior to the grip ring 12 contacting the pipe P, as the nut 10 will not move longitudinally once the grip ring has securely gripped the pipe. Since in many circumstances the pipe P and the nut 10 are not completely rigid, the scenario of the grip ring 12 contacting the pipe prior to or at the same time that the O-ring 14 contacts the pipe is feasible.

FIG. 4 shows the pipe coupling after nut 10 has been properly tightened so that O-ring 14 forms a seal at internal sloping surface and grip ring 12 grips pipe P.

FIG. 5 is a sectional view of the embodiment of the pipe coupling of FIG. 1 illustrating a situation where there is a particularly high pressure fluid in pipe P. Such a case may cause coupling body 16 to be pushed backward (to the left in the figure) thereby opening a small gap between pipe P and the coupling body's shoulder 38 and between O- ring 14 and the coupling body's internal sloping surface 30. As the pipe coupling of the present embodiment comprises a seal or gasket such as O-ring 18, despite the aforementioned gap issue, fluid leakage can be prevented. It should be noted that O-ring 18 also does not hamper the insertion of pipe P as O-ring 18 does not interface with the pipe.

Regardless, in some embodiments of the invention, the pipe coupling does not comprise a seal such as O-ring 18, and it can be seen in FIG. 4 that O-ring 14 can prevent leakage both from along pipe P and from between nut 10 and body 16.

FIG. 6 shows additional embodiments of the invention wherein the seal or gasket, again illustrated by O-ring 14, is disposed adjacent a forward surface 37 of grip ring 12, instead of being positioned between body 16 and grip ring 12 as illustrated in previous figures. As O-ring 14 is thus located within a narrower profile portion of nut 10 due to its internal sloping surface 30, in such situation, the O-ring 14 is typically a bit smaller than when positioned between body 16 and grip ring 12. In order to help retain O-ring 14, in some embodiments the coupling device comprises an annular ring 41 disposed between grip ring 12 and the distal end 27 of nut 10, which is particularly useful if the pipe P is small relative to the coupling device.

In some embodiments, the assembly further comprises a seal supporter 43 disposed "behind" the O-ring; either O-ring 14 as illustrated in FIG. 6; or disposed in "front" of O- ring 14 and behind grip ring 12. The seal supporter 43 is particularly useful when the grip ring has a non-flat rear or front surface (as the case may be), for example, is of a design having relatively large recesses (e.g. spaces between segments 42, and/or channels 44; detailed below, or any other gap or space), and/or when the grip ring is for example a "two tiered" grip ring (e.g. as described in US 6,464,267, particularly with reference Figs. 4-6 therein.

Claims

1. A pipe coupling of the compression type for coupling a pipe to another fixture, the coupling comprising:

a coupling body including a pipe receiving bore;

a tightening element including: a pipe receiving bore, which is co-operable with a connection mechanism of said coupling body, and an internal sloping surface tapering toward a distal end of the tightening element;

a deformable grip ring including: an inner pipe-gripping surface, an outer surface generally corresponding to said internal sloping surface of the tightening element and disposed adjacent thereto, and a seal interface surface; and

a seal which is adjacent the pipe when the pipe is coupled,

wherein when the pipe is coupled, both the seal and grip ring engage with the sloping surface.

2. A pipe coupling according to claim 1, wherein upon coupling of the pipe, the seal is pressed so that it is moved radially inwardly to form a sealing interface with the pipe.

3. A pipe coupling according to claim 1, wherein the coupling body comprises a pipe stopping member.

4. A pipe coupling according to claim 3, wherein the pipe stopping member is an annular shoulder.

5. A pipe coupling according to claim 1, wherein the seal is disposed intermediate a forward surface of the coupling body and a rear surface of the grip ring.

6. A pipe coupling according to claim 1, wherein the seal is disposed in between the grip ring and the distal end of the tightening element.

7. A pipe coupling according to claim 6, further comprising an annular ring disposed between the grip ring and the distal end of the tightening element.

8. A pipe coupling according to claim 6, further comprising an annular ring disposed between the seal and the distal end of the tightening element.

9. A pipe coupling according to claim 1, further comprising a seal supporter for providing support to the seal.

10. A pipe coupling according to claim 9, wherein the seal supporter and seal are disposed between the coupling body and the grip ring.

11. A pipe coupling according to claim 9, wherein the seal supporter and seal are disposed between the grip ring and the distal end of the tightening element.

12. A pipe coupling according to claim 1, further comprising an additional seal disposed between the coupling body and the tightening element.

5 13. A pipe coupling according to claim 1, wherein connection mechanism comprises threads.

14. A pipe coupling according to claim 13, wherein the tightening element is a nut having internal threads.

15. A pipe coupling according to claim 1, wherein the tightening element is a nut.

10 16. A pipe coupling according to claim 1, wherein the pipe-gripping surface comprises at least one barbed rib.