AU707930B2 - A fitting and a transition means for a polymeric pipe - Google Patents

Description

This invention relates to a transition means which makes it possible for pipes of polyethylene, for example, dimensioned for one standard to be joined to fittings which are dimensioned for pipes of a different standard, which may be of similar but not identical inner diameters or outer diameters.

There are several standards which are not compatible with one another with respect to pipes. The nominal metric outside diameter series standard is the most commonly used standard in the world, but some other pipes themselves fall into several different categories, some being dimensioned over the exterior of the pipes, some in the interior of the pipes, and some using the 10 imperial system. Furthermore, the wall thickness may vary. As a result, an inventory problem is encountered which finally adds cost to the end user, and it *eO o is an object of this invention to provide a transition means which will greatly reduce inventory costs.

Specifically, in metric dimensioned pipes, there are four classes namely 15 6, 9, 12 and 15 which are required for pressures of 600 kPa, 900 kPa, 1200 kPa and 1500 kPa, respectively. The wall thickness for each pipe nominal diameter but of different class will obviously vary, but the diameters are identified as the outer diameters, not the inner diameters of the pipes.

:In imperial measurements, there are different standards for the United oelo 20 Kingdom, Australia, the United States of America and Ireland. In the United Kingdom, for example, high density pipes and low density pipes for classes C and D have the same outside diameters for the same nominal sizes. Australian rural pipe is specified on the inside diameter (for example 2 inch bore).

However, most Australian pipes are according to metric standards.

In the United States of America there are three series, namely 160, and 100, and the nominal sizes vary from inside diameter to outside diameter.

A further class SDR9 has a nominal size which is not close to either inside nor outside diameter. Furthermore, the Irish standards have both heavy and normal gauge but the nominal sizes are not readily identifiable with the outside pipe diameter in all instances.

PRIOR ART The closest prior art which is known to the Applicant is Applicant's own Patent Application PCT/AU94/00406 (Australian Application 72236/94), which disclosed a fitting of a similar type to that illustrated herein. The closest prior art referred to in that specification was US Patent No.

4043576 in the name of RIECH and LEHMANN of Switzerland and assigned to George Fischer Aktiengesellschaft. No prior art at all is known to the Applicant wherein a spigot is used as a transition means to accommodate pipes which might vary slightly in diameter, but be required for a relatively small inventory of fittings. Spigots can be produced inexpensively, but fittings require the use of expensive plastics materials and a number of components.

BRIEF SUMMARY OF THE INVENTION In accordance with one form of the invention there is provided a fitting and transition means for connection of a polymeric pipe to said fitting, wherein the diameter of said pipe may vary slightly, said transition means comprising a double-ended hollow spigot having a first end of outer diameter to be retained in said fitting, a second end with a plurality C of annular barbs which extend radially outwardly and are of diameter to engage an inner surface of said pipe with an interference fit, and a radially projecting annular flange between said spigot ends, said fitting comprising a hollow body having an external thread extending at least part way along it from one end, an axially outer internal cylindrical surface extending inwardly from said fitting one end and defining a mouth of diameter to accommodate said spigot annular flange, the inner end of said axially outer internal cylindrical surface terminating in an annular shoulder, a further internal cylindrical surface extending inwardly from said shoulder and being of diameter to accommodate said spigot first end, a resilient gasket surrounding said spigot first end, and a nut threadably engaging said fitting external thread, the configuration being such that tightening of said nut causes movement of said spigot first end and, in turn, sealable engagement of said gasket around said spigot first end and against said shoulder.

In a preferred form of the invention there is provided a nut having at one end an internal thread co-operable with said body external thread, and an inner surface which converges outwardly towards its other end from an abutment surface, and a deformable gripping member having an outer surface which also converges outwardly and an inner surface which comprises radially inward barbs; the dimensions of said spigot, nut, gripping member, gasket and body being such that, said second spigot end is adapted to enter an end of a polymeric pipe, said first end adapted to enter said hollow body and extend through said resilient gasket, wherein tightening of the nut causes relative co-operative movement of said converging surfaces to reduce diameter of said gripping member and enable its said barbs to grip an outer surface of said pipe and also compress said pipe over said spigot second end, while urging said spigot axially into said hollow body in turn deforming said gasket to effect said sealable engagement *9 thereof, with said shoulder of said body and an outer surface of said spigot first end.

a. 20 In a preferred form of the invention said double ended spigot comprises a radially extending annular flange between its first and second ends, said polymeric pipe abutting said annular flange upon said assembly :and thereby effecting said urging of the spigot axially into said body .upon tightening of said nut.

a. a In a preferred form of the invention there is provided a sleeve within said nut abutting an inner end of said deformable member at one sleeve end and abutting said resilient sealing gasket at the other sleeve end upon said assembly thereby effecting said deformation of said gasket upon a tightening of said nut.

In a preferred form of the invention said double ended spigot comprises a radially extending annular flange between its first and second ends, said polymeric pipe abutting one side of said flange and another side of said flange abutting said resilient gasket upon said assembly thereby effecting said deformation of said gasket upon tightening of said nut.

In another form of the invention there is provided a fitting and a transition means for connection of a polymeric pipe to said fitting which transition means is adapted to accommodate pipes of different diameters, said transition means being adapted to fit into the fitting as a single piece construction to join pipes of differing standards to said fitting, wherein said transition means includes a double-ended hollow spigot having a first end of outer diameter to be retained in said fitting, a second end with a plurality of annular barbs which extend radially outwardly and are of diameter to engage an inner surface of said pipe with an interference fit, and a radially projecting annular flange between said spigot ends, said fitting adapted to receive the transition means, including a hollow body having an external thread extending at least part way along it from one end, an axially outer internal cylindrical surface extending inwardly from said fitting one end and defining a mouth of diameter to accommodate said spigot annular flange, the inner end of said axially outer internal cylindrical surface terminating in an annular shoulder, a So. further internal cylindrical surface extending inwardly from said shoulder :oio 20 and being of diameter to accommodate said spigot first end, a resilient gasket surrounding said spigot first end, and a nut threadably engaging oo ~said fitting external thread, said nut having at one end an internal thread '400 co-operable with said body external thread, and an inner surface which converges outwardly towards its other end from an abutment surface, 25 said nut including an internal annular shoulder between its said ends, and a deformable gripping member having an outer surface which also converges outwardly and an inner surface which comprises radially inward barbs, and including a radially outstanding abutment surface o' :5 30 which is abutted by said annular shoulder of said nut upon said tightening of the nut, the dimensions of said spigot, nut, gripping member, gasket and body being such that, said second spigot end is adapted to enter an end of a polymeric pipe, said first end adapted to enter said hollow body and extend through said resilient gasket, wherein tightening of the nut causes relative co-operative movement of said converging surfaces to reduce diameter of said gripping member and enable its said barbs to grip an outer surface of said pipe and also compress said pipe over said spigot second end, while urging said spigot axially into said hollow body in turn deforming said gasket to effect said sealable engagement thereof, with said shoulder of said body and an outer surface of said spigot first end.

BRIEF DESCRIPTION OF THE PREFERRED

EMBODIMENTS

Embodiments of the invention are described hereunder in detail with reference to and as illustrated in the accompanying drawings in which: FIG 1 is a partly sectioned side elevation showing a fitting and spigot assembly associated with a pipe, before its assembly is achieved; and FIG 2 shows the manner in which the assembly is achieved; and FIG 3 shows an alternative arrangement wherein the fitting used differs from the fitting illustrated in our aforesaid Patent Application.

.i:o Referring first to FIGS 1 and 2, a polyethylene pipe 10 has an inner 15 diameter 11 which is somewhat similar to an inner diameter 12 within a ~hollow body 13, and there is provided a gripping member 14 made from a deformable material (in this embodiment being acetal which is a Sma material of greater hardness than polyethylene used in a pipe), the =:gripping member having an outer surface 15 which converges outwardly towards a mouth 16 of nut 23, the gripping member 14 having radially inwardly extending barbs 17, and the inner diameter of gripping member 14 being as close dimensionally as is reasonably feasible to the outer diameter of pipe The fitting comprises a hollow body 13 having an external thread 21 which is threadably engaged by an internal thread 22 of a nut 23. The thread of the body extends approximately half way along the body from the mouth end. There is an axially outer internal cylindrical surface 24 of the body 13 which is of relatively large diameter and which extends into the body 13 from its mouth Ca. *i end and terminates in an annular shoulder 25, and the inner diameter 12 is of the axially inner internal cylindrical surface 26 which, as shown in Fig 2 is subsequently engaged by a first end 27 of a hollow spigot 28.

The nut 23 has an internal abutment surface 31 which upon tightening of the nut 23 over the body 13 bears against an annular abutment surface 32 of the gripping member 14 as seen in Fig 2. The inner surface 33 of nut 23 converges outwardly to be co-operable with the outer surface 15 of gripper member 14, so that as the nut is tightened the effective diameter of gripper member 14 is reduced, in the embodiment shown the gripper member 14 being 10 a split collet.

A spigot 28, besides its first end 27 has a second end 35 which is of a diameter which will suit a specific production run of pipes, whether they be 9 metric or imperial, different pipes will require different spigots 28. The second end 35 is provided with a plurality of radially outstanding barbs 36, and as seen 15 in Fig 2, when the nut 23 is tightened, the barbs 36 engage the inner wall of pipe 10 while the barbs 17 of gripper member 14 are arranged to lie intermediate to the barbs 36 and thereby slightly distort the pipe walls and achieve a good firm grip of pipe 10, both the inner and outer surfaces of the ends of which being firmly clamped by the respective barbs.

o 20 The resilient sealing gasket 38 is in this embodiment an O-ring, and it is urged inwardly into the body 13 by tightening of nut 23, there being provided a stepped sleeve 39 as in our aforesaid Patent Application. The nut pressure then deforms the O-ring 38 to effect a very positive seal both against the outer surface of the first end 27 of spigot 28 and against both the cylindrical surface 24 and the shoulder 25 of the body. It will be noted from Fig 2 that the first end 27 of spigot 28 projects into the internal surface 26 which is in the fitting body 13 and extends inwardly from the mouth end 16 of the nut 23, beyond the 6 shoulder 25. Thus the connected end of pipe 10 is restrained against deflection of a bending type as well as against withdrawal from the body 13 of the fitting.

The end 40 of the body 13 will take various shapes, and as illustrated comprises a hollow projecting nipple 41 which has a thread to mate with a standard pipe fitting. However, the end 40 can be a duplicate but of different diameter from the mouth end of the fitting, so as to be able to join with pipes of different diameters. A radially outer flange 43 separates a first and second end of spigot 28, and also provides an abutment at the first side which bears against the sleeve 39 and an abutment on the second side which bears against the end of the pipe It will be seen that upon assembly, the spigot is driven with its second end 35, the barbed end, into the end of pipe 10, and the whole assembly can then be pushed into the body 13, past the sleeve 39 and the resilient gasket 38 to finally engage the inner surface 26 of the body, and at the ."same time the gripping member 14 is restrained against inward movement after the resilient gasket 38 has been deformed, and further o tightening in the nut causes radial closure of the split collet 14 over the 20 outer surface of pipe 10, with the barbs of the split collet lying between the barbs 36 of the second end 35 of the spigot 28. Tightening of the nut also performs a secondary function of urging the spigot axially into the whole embodiment, so that the spigot is firmly clamped with respect to the body.

The above embodiment has specific reference to a fitting of the same type as that described in our aforesaid Patent Application. However, it is not necessary that a fitting which is universal in its construction should o .be used, and FIG 3 shows a second embodiment where the sleeve 39 is dispensed with, and the body 13a can therefore be of shorter length, the O-ring 38a being compressed by the flange 43a, and the spigot first end 27a being shorter than in the first embodiment. Other features of construction are substantially similar to the first embodiment except that the fitting is somewhat shorter than in the first embodiment, and similar elements bear the same designation numbers with the suffix In this specification a "nominal" size refers to a pipe dimension (say of 2 inch outside diameter) which is within five percent of a 2 inch dimension.

For the purpose of this specification, a pipe is regarded as being within "nominal" size if its actual outside diameter lies within ten percent of the "nominal" size for a 2 inch pipe, between 1.8 inches and 2.2 inches.

A pipe of polyethylene of that size can be expanded by twelve percent of the nominal 2 inches by the barbs on the second end of the spigot, but not less than two percent to ensure satisfactory pipe retention.

To accommodate up to seven sizes of the aforementioned standards, it is necessary for an inventory to include 250 hollow spigots, but only gripping members, which, being split rings, are capable of considerable diametral compression.

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8 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A fitting and transition means for connection of a polymeric pipe to said fitting, wherein the diameter of said pipe may vary slightly, said transition means comprising a double-ended hollow spigot having a first end of outer diameter to be retained in said fitting, a second end with a plurality of annular barbs which extend radially outwardly and are of diameter to engage an inner surface of said pipe with an interference fit, and a radially projecting annular flange between said spigot ends, said fitting comprising a hollow body having an external thread extending at least part way along it from one end, an axially outer internal cylindrical surface extending inwardly from said fitting one end and defining a mouth of diameter to accommodate said spigot annular flange, the inner end of said axially outer internal cylindrical surface terminating in an annular shoulder, a further internal cylindrical surface extending inwardly from said shoulder and being of diameter to accommodate said spigot first end, a resilient gasket surrounding said spigot first end, a nut S• threadably engaging said fitting external thread, said nut having at one Send an internal thread co-operable with said body external thread, and 9: 20 an inner surface which converges outwardly towards its other end from an abutment surface, said nut including an internal annular shoulder between its said ends, and a deformable gripping member having an outer surface which also converges outwardly and an inner surface which comprises radially V 25 inward barbs, and including a radially outstanding abutment surface SI. which is abutted by said annular shoulder of said nut upon said tightening of the nut, the dimensions of said spigot, nut, gripping member, gasket and °body being such that, said second spigot end is adapted to enter an end i of a polymeric pipe, said first end is adapted to enter said hollow body and extend through said resilient gasket, wherein tightening of the nut causes relative co-operative movement of said converging surfaces to reduce diameter of said gripping member and enable its said barbs to grip an outer surface of said pipe and also compress said pipe over said spigot second end, while urging said spigot axially into said hollow body in turn deforming said gasket to effect said sealable engagement thereof, with said shoulder of said body and an outer surface of said spigot first end.

Claims (4)

1. 2. A fitting and transition means according to claim 1 wherein said double ended spigot comprises a radially extending annular flange between its first and second ends, said polymeric pipe abutting said annular flange upon said assembly and thereby effecting said urging of the spigot axially into said body upon tightening of said nut.
2. 3. A fitting and transition means according to claim 1, further comprising a sleeve within said nut abutting an inner end of said deformable member at one sleeve end and abutting said resilient sealing gasket at the other sleeve end upon said assembly thereby effecting said deformation of said gasket upon tightening of said nut. e" 0,4. A fitting and transition means according to claim 1, wherein said double ended spigot comprises a radially extending annular flange between its first and second ends, said polymeric pipe abutting one side of said flange and another side of said flange abutting said resilient gasket upon said assembly thereby effecting said deformation of said S• gasket upon tightening of said nut.
3. 5. A fitting and a transition means for connection of a polymeric •pipe to said fitting which transition means is adapted to accommodate pipes of different diameters, said transition means being adapted to fit into the fitting as a 4 4single piece construction to join pipes of differing standards to said 4 4• fitting, wherein said transition means includes a double-ended hollow spigot having a first end of outer diameter to be retained in said fitting, a second end with a plurality of annular barbs which extend radially outwardly and are of diameter to engage an inner surface of said pipe with an interference fit, and a radially projecting annular flange between said spigot ends, said fitting adapted to receive the transition means, including a hollow body having an external thread extending at least part way along it from one end, an axially outer internal cylindrical surface extending inwardly from said fitting one end and defining a mouth of diameter to accommodate said spigot annular flange, the inner end of said axially outer internal cylindrical surface terminating in an annular shoulder, a further internal cylindrical surface extending inwardly from said shoulder Z Y and being of diameter to accommodate said spigot first end, a resilient gasket surrounding said spigot first end, and a nut threadably engaging said fitting external thread, said nut having at one end an internal thread co-operable with said body external thread, and an inner surface which converges outwardly towards its other end from an abutment surface, said nut including an internal annular shoulder between its said ends, and a deformable gripping member having an outer surface which also converges outwardly and an inner surface which comprises radially inward barbs, and including a radially outstanding abutment surface which is abutted by said annular shoulder of said nut upon said tightening of the nut, the dimensions of said spigot, nut, gripping member, gasket and body being such that, said second spigot end is adapted to enter an end of a polymeric pipe, said first end is adapted to enter said hollow body and extend through said resilient gasket, wherein tightening of the nut causes relative co-operative movement of said converging surfaces to reduce diameter of said gripping member and enable its said barbs to S• grip an outer surface of said pipe and also compress said pipe over said spigot second end, while urging said spigot axially into said hollow body S. in turn deforming said gasket to effect said sealable engagement thereof, with said shoulder of said body and an outer surface of said spigot first end. A fitting and transition means substantially as hereinbefore 25 described with reference to FIGS 1 and 2.
4. 7. A fitting and transition means substantially as hereinbefore described with reference to and as illustrated in FIG 3. Dated this 25th day of May 1999 PHILMAC PTY LTD By their Patent Attorneys, COLLISON CO. ABSTRACT A transition means for the connection of a polymeric pipe (10) to a fitting (13) which is dimensioned to accommodate pipes (10) of slightly different diameters, and comprises a double-ended hollow spigot (28) with one end (27) having an outer diameter which is appropriate for a standard fitting (13) and the other end (35) having radially projecting barbs (36) of diameter to engage the inner surface of a pipe (10) with an interfering fit, so arranged that upon assembly to a fitting, the transition barbed end (35) can be driven into the bore of a pipe end, the other end can be accommodated by the fitting and upon S: 10 tightening of a fitting nut a deformable gripping member (14) with internal barbs (17) contained within the fitting (13) can engage the outside of the pipe 0: (10) and also can press the pipe over the external barbs (36) of the inserted S00 spigot. 0 0 o0