NZ272524A - Pipe fitting; comprises a double ended hollow spigot having a first end sealably retainable within a pipe fitting and a second end with projecting barbs to engage the pipe - Google Patents

Abstract

An adaptor 17 for the connection of a polymeric pipe 10 to a filling 13 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. The fitting 13 includes a fitting nut 23, threadedly engaged with the fitting body, a deformable gripping member 14 with internal barbs 17 which engage the outside of the pipe 10 and also presses the pipe 10 over the external barbs 36 of the inserted spigot 28, and an elastomeric seal 38 which seals against the other end 35 of the spigot 28.

Description

New Zealand No. International No. 272524 PCT/ TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 12.07.1994; Complete Specification Filed: 07.07.1995 Classification:^) F16L47/04; F16L21/06 Publication date: 24 June 1 997 Journal No.: 1417 NEW ZEALAND PATENTS ACT 1 953 COMPLETE SPECIFICATION Title of Invention: Transition means between fittings dimensioned to one standard and pipes dimensioned to another standard Name, address and nationality of applicant(s) as in international application form: PHIIIVIAC PTY LTD, a company incorporated under the laws of South Australia, of 53 Deeds Road, North Plympton, South Australia, Australia 272524 Patents Form No. 5 THE PATENTS ACT 1953 £ * / /f\ * r- ' ^ 13JUL JG95 •; foJ COMPLETE SPECIFICATION ^ TRANSITION MEANS BETWEEN FITTINGS DIMENSIONED TO ONE STANDARD AND PIPES DIMENSIONED TO ANOTHER STANDARD I, PHILMAC PTY LTD, a company incorporated under the laws of South Australia, of 53 Deeds Road, North Plympton, South Australia, Australia, hereby declare the invention, for which I pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page la) 272524 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 diarfteter 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 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 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. Australiip* % N T <£ rural pipe is specified on the inside diameter (for example 2 inch bore). ■a — "A However, most Australian pipes are according to metric standards. ^ 13 J U L 1995 X 25 In the United States of America there are three series, namely 160, 75 ' ■>•£ e 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 noir outside diameter. Furthermore, the Irish standards have both heavy and normal 1 a 27 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 the Applicant's own Patent Application PCT/AU94/00406 (Australian Application 72236/94), which disclosed a fitting substantially identical to a fitting 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 Briefly, in this invention a transition means for the connection of a polymeric pipe to a fitting which is dimensioned to accommodate pipes of slightly different diameters, and comprises a double-ended hollow spigot with one end having an outer diameter which is appropriate for a standard fitting and the other end having radially projecting barbs of diameter to engage the inner surface of a pipe with an interfering fit, so arranged that upon assembly to a fitting of the general type described in Applicant's aforesaid application, the transition barbed end can be driven into the bore of a pipe end, the other end can be accommodated by the fitting, and upon tightening of a fitting nut, a deformable gripping member with internal barbs contained within the fitting can engage the outside of the pipe and also can press the pipe over the external barbs of the inserted spigot.

Even with the transition means referred to in the specification, at the time of writing this specification, there is a need for a total of 250 transition tiwa J ( spigots and 50 tapered gripping members to meet the requirements for seven pipe sizes, but the lower cost of the transition spigots renders the inventory requirements viabie. Otherwise, if independent fittings for respective pipe dimensions were required, there would of course be a requirement for 250 5 fitting sizes instead of 7. These figures are expected to vary with the passage of time, and in particular with the rationalisation of standards.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention are described hereunder in detail with reference to and are illustrated in the accompanying drawings in which: 10 Fig 1 is a partly sectioned side elevation showing a fitting and spigot assembly associated with a pipe, before its assembly to the fitting; 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. 15 Referring first to Figs 1 and 2, a polyethylene pipe 10 has an inner 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 material of greater hardness than polyethylene used in a pipe), the gripping member having an 20 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 10.

The fitting comprises a hollow body 13 having an external thread 21 25 which is threadibly 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 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 5 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 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.

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 25 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 , i 5 J L 1935 ■>' o./ If!*'*'-- 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 10.

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 tightening in the nut causes radial closure of the split collet 14 over the 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 similar to one described and claimed in our aforesaid Patent Application. However, it is not necessary that a fitting which is universal in its construction should 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* ■■ '•/ 2 / >: d v /j 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 "a".

In this specification a "nominal" size refers to a pipe dimension (say of 2 inch outside diameter) which is within five percent (5%) 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 (10%) of the "nominal" size - for a 2 inch pipe, between 1.080 inches and 2.020 inches.

A pipe of polyethylene of that size can be expanded by twelve percent (12%) of the nominal 2 inches by the barbs on the second end of the spigot, but not less than two percent (2%) 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 50 gripping members, which, being split rings, are capable of considerable diametral compression. 6 27 2 5 24

Claims (8)

WHAT WE CLAIM ISs

1. In combination, a fitting and transition means for connection of a polymeric pipe to said fitting, said transition means comprising a double-ended hollow spigot having a 5 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 10 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 15 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 20 spigot first end and against said shoulder.

2. In combination, a fitting 2nd transition means according to claim 1, 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 25 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/{^Tw t barbs, t# N -6 Vutf 27 2 52 4 the dimensions of said spigot, nut, gripping member, gasket and body being such that, upon assembly said second spigot end enters an end of a polymeric pipe, said first end enters said hollow body and extends through said resilient gasket, tightening of the nut causes relative co-operative movement of 5 said converging surfaces to reduce diameter of said gripping member and cause 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 scalable engagement thereof, with said shoulder of said body and an outer surface of said spigot first 10 end.

3. In combination, a fitting and transition means according to claim 2 wherein said nut comprises an internal annular shoulder between its said ends, and said gripping member has a radially outstanding abutment surface which is abutted by said annular shoulder upon said tightening of the 15 nut and thereby assists in said urging of the spigot axially into said hollow body.

4. In combination, a fitting and transition means according to claim 2 wherein said double ended spigot comprises a radially extending annular flange between its first and second ends, said polymeric pipe abutting 20 said annular flange upon said assembly and thereby effecting said urging of the spigot axially into said body upon tightening of said nut.

5. In combination, a fitting and transition means according to claim 2, further comprising a sleeve within said nut abutting an inner end of said deformable member at one sleeve end and abutting said resilient sealing 25 gasket at the other sleeve end upon said assembly thereby effecting said deformation of said gasket upon tightening of said nut.

6. In combination, a fitting and transition means accordin claim 2, wherein said double ended spigot comprises a radially extending 8 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.

7. Transition means substantially as hereinbefore described with reference to and as illustrated in Figs 1 and 2.

8. Transition means substantially as hereinbefore described with reference to and as illustrated in Fig 3. END OF CLAIMS