PIPE FITTING

Abstract

A pipe fitting (40) for coupling pipes together, the pipe fitting (40) having a body (10) with at least two substantially cylindrical rigid open ends (12, 14), each end for joining to an end of a pipe, a section (30) intermediate two of the substantially rigid open ends that has a spring configuration defined by at least one slot and at least one spring member; and a sleeve (30) surrounding the spring section, wherein the sleeve is formed from an elastomeric material that fluidly seals the slot(s) in the spring section.

Claims

1. A pipe fitting for coupling pipes together, the pipe fitting having a body with at least two substantially cylindrical rigid open ends, each end for joining to an end of a pipe, a section intermediate two of the substantially rigid open ends that has a spring configuration defined by at least one slot and at least one spring member; and a sleeve surrounding the spring section, wherein the sleeve is formed from an elastomeric material that fluidly seals the slot(s) in the spring section.

2. The pipe fitting of claim 1 in the form of an elbow, a coupling, a, T joint, a Y joint or an X joint.

3. The pipe fitting of claim 1, wherein the spring configuration is helical.

4. The pipe fitting of claim 1, wherein the spring configuration is non-helical.

5. The pipe fitting of claim 4, wherein the spring configuration includes at least two interconnected cylindrical spring members.

6. The pipe fitting of claim 1, wherein the body is injection moulded from a thermoplastics material.

7. The pipe fitting of claim 6, wherein the thermoplastics material is selected from polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP)or acrylonitrile butadiene styrene (ABS).

8. The pipe fitting of claims 7, wherein the spring configuration is integrally formed with the body during the injection moulding.

9. The pipe fitting claim 8, wherein the sleeve is over moulded onto the body.

10. The pipe fitting of claim 1, wherein the pipe fitting can respond to a bending force by bending at an angle of up to about 10, suitably up to about 5.

11. A method of manufacturing the pipe fitting of claim 1 comprising the steps of injection moulding the body of the fitting from a thermoplastics material in a first moulding step and a second step of overmoulding the elastomeric material onto the body to form the sleeve.

12. The method of claim 11, wherein, wherein the thermoplastics material is selected from polyethylene (PE), polyvinyl chloride (PVC) or acrylonitrile butadiene styrene (ABS).

13. The method of claim 11, wherein the elastomeric material is a butadiene styrene rubber.

14. The method of claim 13, wherein the thermoplastics material is ABS.

15. A body for the pipe fitting of claim 1, the body having at least two substantially cylindrical rigid open ends for joining to a pipe and a section intermediate the ends that is resilient with a spring configuration with at least one slot and at least one spring member.

16. A pipe system comprising a pipe fitting of any one of claims 1, with at least one pipe connected thereto.

Description

DETAILED DESCRIPTION

[0033] A pipe fitting and a pipe assembly in accordance with this disclosure may manifest itself in a variety of forms. It will be convenient to hereinafter describe several embodiments of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings:

[0034] FIG. 1 is a perspective view of one aspect of the disclosed body of a pipe fitting that is in the form of an elbow joint;

[0035] FIG. 2 is a perspective view a pipe fitting that has the body as shown in FIG. 1;

[0036] FIG. 3 is a perspective view of another aspect of the disclosed body of a pipe fitting that is in the form of a T junction;

[0037] FIG. 4 is a perspective view of another one aspect of the disclosed body of a pipe fitting that is in the form of a Y junction;

[0038] FIG. 5 is a perspective view of another one aspect of the disclosed body of a pipe fitting that is in the form of an elbow joint;

[0039] FIG. 6 is a perspective view of one aspect of the disclosed pipe fitting in the form of a coupling;

[0040] FIG. 7 is a perspective view of the body of the pipe fitting as shown in FIG. 6 without the sleeve;

[0041] FIG. 8 is a perspective view of the sleeve of the pipe fitting as shown in FIG. 6;

[0042] FIG. 9 is a photograph showing a test set up for testing angular deformation of the coupling as shown in FIG. 6;

[0043] FIG. 10 is a view of the test rig shown in FIG. 9 with the coupling bent at an angle;

[0044] FIG. 11 is a close up view of the bent coupling;

[0045] FIG. 12 is a close up of the coupling after bending in the test rig;

[0046] FIG. 13 is an interior view of the coupling show in FIG. 12;

[0047] FIG. 14 is a view of a further test ring for testing rotational deformation of the coupling as shown in FIG. 15 is a detail of the coupling in the test rig shown in FIG. 15 rotated at 90;

[0048] FIG. 16 is an interior view of the coupling after the rotation as shown in FIG. 15;

[0049] FIG. 17 shows a pipe assembly including the coupling as shown in FIG. 8;

[0050] FIG. 18 shows the pipe assembly as shown in FIG. 17 subjected to a bending force;

[0051] FIG. 19 shows a prior art pipe assembly with a Y fitting;

[0052] FIG. 20 shows the pipe assembly shown in FIG. 19 after being subjected to a bending force;

[0053] FIG. 21 shows another prior art pipe assembly with a Y fitting;

[0054] FIG. 22 shows the pipe assembly as shown in FIG. 21 after catastrophic failure;

[0055] FIG. 23 shows a pipe assembly including the coupling as shown in FIG. 6 under a bending stress;

[0056] FIG. 24 shows the pipe assembly shown in FIG. 23 after the bending stress has been released;

[0057] FIG. 25 shows a further pipe assembly including the coupling as shown in FIG. 6 subject to a further deformation test;

[0058] FIG. 26 shows the pipe assembly as shown in FIG. 26 after the deformation shown in FIG. 25;

[0059] FIG. 27 shows the pipe assembly as shown in FIG. 25 subjected to further deformation; and

[0060] FIG. 28 shows the pipe assembly shown in FIG. 28 being deformed to the maximum amount.

[0061] In FIG. 1 reference numeral 10 refers generally to the body of an elbow pipe fitting in accordance with the invention. The fitting body 10 is injection moulded ABS. The fitting body 10 has two cylindrical ends, one having a male connection 12 and the other a female connection 14 for connection to complimentary ends of pipes.

[0062] The fitting body 10 has a spring section 20 with a non-helical spring configuration. The spring section has three cylindrical spring members 22 with slots 24 in between. Each alternate spring member 22 is connected by lands 26 that are disposed 90 degrees apart so as to maintain the integrity of the spring section.

[0063] The thickness of each spring member 22 and wall thickness thereof determine the stiffness and stress level of each spring member 22. The number of slots 24 and number of spring members 22 may determine the spring stiffness.

[0064] FIG. 2 shows the complete elbow fitting 40 in which the fitting body 10 has a sleeve 30 of ABS elastomer overmoulded thereon. The sleeve 30 covers and fills slots 22 so as to provide water impermeability and a smooth inner surface. This contributes to a laminar flow.

[0065] The butadiene styrene elastomer of the sleeve is compatible with the ABS body so as to resist delamination.

[0066] The elastomeric nature of the sleeve 30 allows the sleeve 30 to bend, compress or expand when the fitting is subject to stress. The elastomeric nature of the sleeve 30 also contributes to the stiffness of the spring. Further the spring members 22 act as reinforcement for the sleeve 30. This has a distinct advantage over known types of flexible pipe joints that are simply rubber cylinders that are connected to pipes by hose clips. In practice these rubber joints clips are not considered to be strong enough for underground use as they are subject to compression under the weight of the ground that may block or interfere with water flow.

[0067] The synergistic combination of the sleeve and spring members may provide considerable resistance to compression, expansion, rotational and bending forces.

[0068] FIGS. 3 and 4 show T and Y fitting bodies 10 in which each arm 8,9 of the joint has a spring section 20.

[0069] FIG. 5 shows an alternate elbow fitting body 10 in which the spring section 20 is in the curve of the elbow.

[0070] FIG. 6 shows a still further pipe fitting 29 in the form of a straight coupling body with a sleeve 30 overmoulded thereon.

[0071] FIG. 7 shows the body of the pipe fitting as shown in FIG. 6.

[0072] FIG. 8 is a schematic view of the over moulded sleeve 30. In this view the inner wall of the overmoulding may be seen to have grooves 32 and lands 34 that are complimentary to the spring member 22 and slots 24 in the spring section 20.

Product Testing

Trial 1

[0073] A straight 100 mm coupling 29 as shown in FIG. 6 was provided. The coupling 29 was glued at each end to a 100 mm diameter pipe 40, 42 as per conventional techniques. The coupled pipes were attached to a test rig as shown in FIG. 9. The test rig is able to selectively raise pipe 42 about a bend axis A corresponding to the location of coupling 29.

[0074] The test was conducted in two parts. In the first part the aim was to progressively deflect pipe 42 relative to pipe 40 about coupling 29 whilst passing a 98 mm sphere through the coupling until the maximum angle was reached at which the sphere would still pass through.

[0075] The maximum angle at which the sphere would pass through the coupling 29 was 12.9. The coupling deflected at this angle is shown in FIG. 10.

[0076] In the second part of the trial, deflection was continued in an attempt to determine the angle at which the coupling 29 failed. The maximum deflection angle of the test rig is 52.5. The coupling 29 was deflected to this maximum angle as shown in FIG. 11. The coupling 29 did not fail.

[0077] The test rig was returned to the original position. The coupling 29 was removed from the pipes 40, 42 and examined. FIG. 12 shows that although there is some deformation it was not fractured nor broken.

[0078] FIG. 13 shows the interior of the coupling 30 after maximum deformation showing that one spring member 22 was deformed and had delaminated from the sleeve 30.

Trial 2

[0079] The test set up is shown in FIG. 14. In this trial a coupling 29 was subjected to a rotational force. The coupling 29 having a 100 mm diameter was connected at each end to a respective 100 mm diameter T fitting 44, 46 by gluing as per conventional techniques in a vertical orientation. The upper T fitting 44 was in turn further connected to a 100 mm diameter pipe 48.

[0080] The lower T fitting 46 was fixed against rotational force and the upper pipe 48 was fixed to a chain 50 one meter from the coupling 29 for measured application of a rotational force.

[0081] The test was conducted in three parts, the first two parts were in a similar manner to trial 1. In the first part of the trial, a rotational force was applied whilst passing a 98 mm diameter sphere through the coupling 29. The maximum angle of rotation at which the sphere could pass though the coupling 29 was 13.2 with an applied force of 11.0 kg. This is the angle of rotation as shown in FIG. 15.

[0082] The coupling 29 was then subjected to further rotational force to determine at which angle the coupling 29 would fail. The coupling 29 was subject to rotation to an angle of 90, which was the maximum angle of the test rig.

[0083] FIG. 15 shows that at 90, the coupling 29 is deformed but has not ruptured or otherwise failed. It was observed that with a force of 29.0 kg and a rotational angle of 89, two internal spring members 22 broke, as shown in FIG. 16. However, there was no delamination of the sleeve 30 from the coupling body 10.

[0084] The rotational force was released and the coupling resumed its original position and showed some deformation. The coupling was removed from the pipe 48 and subjected to a pressure test of 30 kPa for 5 minutes. No leakage was observed.

Trial 3

[0085] FIG. 17 shows a 100 mm diameter pipe assembly 50 including a 45 Y fitting 52. A pipe 52 is glued to the vertical inlet of Y fitting 52 as per conventional DWV (Drain Waste Vent) techniques. The angled inlet 51 of the Y is fitted to a coupling 29 of the same type as used in Trials 1 and 2. The other end of the coupling 29 is coupled to an expansion joint 56 which in turn is coupled to a pipe 58. Expansion joints 56 have telescopic members that are used to accommodate laterally moving soil.

[0086] FIG. 18 shows the test rig set up in which the fitting 52 was subjected to a bending force of 14.4 kg at an angle of 60, which was maintained for a period of 25 hours. After this period, the force was removed with no damage at all noted on the Y fitting 52, coupling 29 or expansion joint 56.

Trial 4

[0087] Part A

[0088] A pipe assembly 66 was formed by joining a 100 mm diameter 45 Y fitting 60 as shown in FIG. 19 with two female upper ends to two pipes 62, 64 by conventional gluing. The glue had a 24 hour drying time.

[0089] The pipe assembly 66 was placed into a test rig as shown in FIG. 18. Each piece of pipe 62, 64 had a pipe stiffener inserted therein so as to transfer the force directly to the fitting 60. A force was applied to pipe 64 one meter from the fitting with pipe 62 fixed 1 meter from the fitting.

[0090] With a force of 88.0 kg the pipe assembly had deformed to an angle of 53, at which point the glue failed as shown by arrow B in FIG. 20.

[0091] Part B

[0092] The trial as described in Part A was repeated with another 45 Y fitting 70 as shown in FIG. 21. With a force of 112.0 kg the Y fitting 70 exhibited catastrophic failure at an angle of 58 as shown in FIG. 22. There was no damage to the pipe.

[0093] Part C

[0094] The trial as described in Part B was repeated except that coupling 29 was inserted between the 45 arm Y fitting and the pipe 74. In this case, however, the use of a pipe stiffener was not necessary as a load of only 13 kg was required to produce an angle of 59.37.

[0095] With a force of 13.0 kg, an angle of 60 was produced as shown in FIG. 23. This angle was maintained for a period of 55 hours with no damage to the Y fitting 70, the pipes or the coupling. The load was removed and in 30 minutes the coupling 30 had returned to an angle of 51.5 with no damage as shown in FIG. 24.

Trial 5

[0096] A coupling 29 was fitted to the arm of a Y fitting 70 as previously described and pipes 80, 82, 84 were fitted to the Y fitting and coupling 29 as shown in FIG. 25. Weights 86 were fitted to the end of pipe 80 that caused the coupling 29 to deform at an angle of about 30.

[0097] When the weights 86 were removed, the coupling 29 returned to almost the original position as shown in FIG. 26.

[0098] FIGS. 27 and 28 show the coupling 29 subjected to even further deformation.

[0099] These above test results clearly show that the pipe fittings as disclosed herein may deform to a considerable degree without failure. The pipe fittings resist both angular and rotational deformation. The test rigs that were used in the above trials were designed to test conventional thermoplastic pipe fittings to failure. However, no test rig was able to cause the coupling 29 to delaminate or leak. This clearly shows the trial results for the disclosed coupling are indeed unexpected and surprising.

Trial 6

[0100] The coupling was subjected to a cyclic testing plastic telescopic waste connectors according to Australian standard AS2888.11. This test provides a method of subjecting the expansion joint of a plastics telescopic bath waste connector to cyclic movements consistent with the temperature-induced expansion and contraction experienced by such fittings in service.

[0101] Prior to testing, coupling 29 was conditioned for 24 hours at 20 degrees C. After conditioning, the coupling 29 was subjected to a hydrostatic pressure tests at 350 kPa for 65 seconds. There were no leaks.

[0102] The coupling 29 was placed in a test rig and subjected to 5000 cycles of up to 15 mm movement at a cycle time of 6 seconds.

[0103] The coupling 29 was subject to another hydrostatic pressure tests at 350 kPa for 65 second. No leaks were observed.

[0104] The results for trial 6 show that the coupling can also resist expansion and contraction in a manner that not only meets but exceeds the standard for telescopic fittings. Thus the disclosed pipe fittings may be used in place of telescopic fittings. Additional, the pipe fitting as disclosed can also resist bending and rotational forces that a conventional telescopic fitting cannot.

[0105] Although the pipe fittings that were tested had a 100 mm diameter, it will be appreciated that the pipe fittings as disclosed herein may be manufactured for coupling to pipes of any other size, suitably up to and including pipes having diameter of 375 mm.

[0106] It will therefore be appreciated that the pipe fittings as disclosed herein can provide considerable advantages over known fittings. The disclosed fittings have no moving parts as compared to the known expansion and swivel joints and are more cost effective to produce. The fittings may therefore be economically employed on a much wider range of projects than conventional swivel and telescopic joints. They may be used in underground pipe systems where there is some risk of ground movement, in areas where the ground may freeze and in areas where there is a real risk of ground movement due to earth tremors. Other suitable uses include under heavy traffic areas.

[0107] The forces generated by such ground movement are generally transmitted along the length of a pipe to the points at which the pipes are connected to a fitting or other pipe. Failure therefore generally occurs at the pipe fittings. It will be appreciated that by using the fittings as described herein to connect pipes, that these forces may be absorbed without causing cracking or splitting of the pipes or any rigid fittings associated therewith.

[0108] The pipe fittings may also be used to repair or replace broken or cracked pipes.

[0109] The pipe fittings may easily be installed and connected to pipes using conventional solvent welding techniques.

[0110] The pipe fittings are especially advantageous for drain waste systems. These systems operate at low pressure and rely on gravity to move fluids (and often entrained solids).

[0111] It is therefore desirable to use fittings that are as smooth as possible on their interior surfaces. Any sharp interior ridges or corrugations may catch debris or accumulate buildup of material and cause clogging. The absence of interior snags also makes it much easier to snake out or rod out a clogged pipe using long flexible tools made for this purpose.

[0112] It may also be appreciated that the complimentary surface of the sleeve 30 with respect to the coupling body provides such a desirable smooth uninterrupted inner surface to the fitting. This offers a significant advantage over known corrugated flexible fittings.

[0113] It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.