AU2012200745B2 - Tapping Saddle - Google Patents

Abstract

Abstract A tapping saddle comprising a pair of arcuate bands that 5 when fixed together define a clamp adapted to engage the exterior of a pipe, each band having abutting flanges on either end with fasteners arranged to extend through the flange to clamp the saddle to the exterior of the pipe, each flange having a profile to accommodate a flange of 10 the other band whereby when one band is reversed the diameter of the clamp changes. 3130266_1 (GHMatters) P86402.AU.1 7/02/12 1lL~ -~ '3 C) ~1~,-. & w

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Tyco Water Pty Limited Invention Title: Tapping Saddle The following statement is a full description of this invention, including the best method for performing it known to me/us: - 2 TAPPING SADDLE This invention relates to tapping saddles especially for use with plastic pipes. Tapping saddles are a well 5 known form of equipment that can be used to provide fluid access to larger diameter pipes. Most tapping saddles are specifically designed for a particular diameter pipe. However with the more recent 10 introduction of oriented PVC pipes the stiffness of the pipe varies which means that existing tapping saddles could cause crushing and buckling of the pipe leading to failure of the saddle installation. To counter this problem a new Australian tapping saddle standard has been 15 developed (see AS/NZS 4793:209) that distinguishes between high stiffness rigid pipes and low stiffness flexible pipes. The standard sets out specific testing requirements for the two types of pipes. 20 Attempts to design tapping saddles with control of the clamping forces have partially resolved this problem but to date there has been no successful design that operates satisfactorily on both flexible and rigid.pipes. 25 It is these issues that have brought about the present invention. According to one aspect of the present invention there is provided a tapping saddle comprising a pair of 30 arcuate bands that when fixed together define a clamp adapted to engage the exterior of a pipe, each band having abutting flanges on either end with fasteners arranged to extend through the flanges to clamp the saddle to the 31302661 (GHMatters) P86402.AU.1 7/02/12 -3 exterior of the pipe, each flange having a profile to accommodate a flange of the other band whereby when one band is reversed the diameter of the clamp changes. 5 Preferably, one band has a projecting hollow spigot to define an off take. The spigot is preferably internally threaded at an outer end with a recess on an inner end to adapted to 10 accommodate a sealing gasket. The sealing gasket preferably is an annulus with walls that taper inwardly towards the periphery. The inner wall is preferable furnished with a V shaped groove. 15 In a preferred embodiment the bands carry indicators that show the orientation of the bands. Preferably each band has one flange with a male 20 abutment surface and the other with a female abutment surface whereby the bands can be assembled male to male and female to female in one orientation and male to female and male to female in another orientation. 25 An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a perspective view of a tapping saddle in accordance with an embodiment of the invention, 30 Figure 2 is an end elevational view of the saddle, Figure 3 is a side elevational view of one side of the saddle, Figure 4 is a side elevational view of the other side 31302661 (GH Matters) P86402.AU.1 7/02/12 -4 of the saddle, Figure 5 is a perspective view of an off take that forms one half of the saddle, Figure 6 is a plan view of the off take, 5 Figure 7 is a side elevational view of the off take, Figure 8 is an underside view of the off take, Figure 9 is a side elevational view of the off take, Figure 10 is an opposite side elevational view of the off take, 10 Figure 11 is a section taken along the lines F-F of Figure 10, Figure 12 is a cross sectional view taken along the lines G-G of Figure 7, Figure 13 is a perspective view of a back strap that i5 constitutes the other half of the tapping saddle, Figure 14 is a plan view of the back strap, Figure 15 is an end elevational view of the back strap, Figure 16 is an underside view of the back strap, 20 Figure 17 is a side elevational view from one side of the back strap, Figure 18 is a side elevational view from the other side of the back strap, Figure 19 is a cross sectional view taken along the 25 lines F-F of Figure 18, Figure 20 is a perspective view of a gasket forming part of the saddle, Figure 21 is a plane view of the gasket, Figure 22 is a side elevational view of the gasket, 30 and Figure 23 is a cross sectional view taken along the lines D-D of Figure 22. 3130266_1 (GHMatters) P86402.AU.1 7/02/12 -5 The tapping saddle 10 illustrated in the accompanying drawings essentially comprises a pair of annular clamping members 20, 30 that are clamped together by fasteners 10, 12 located on diametrically opposed sides of the saddle s 10. One clamping member 20 defines an off take and the other clamping member 30 defines a back strap. Each clamping member is cast in ductile iron and has an annular wall 21, 31 with an interior clamping surface 29, 39 that terminates in radially extending flanges 22, 23, 32, 33. 10 The off take 20 has a centrally positioned upstanding spigot 25 that is internally threaded at an outer end 26 and has a recess 27 at an inner end to accommodate a sealing gasket 70. The threaded end 26 of the spigot 25 facilitates the attachment of pipes, taps, valves or any is other suitable plumbing attachment. The interior clamping surfaces 29, 39 of the off take 20 and back strap 30 are lined with a coating of fusion bonded epoxy. The two clamping members 20, 30 are secured together 20 on each side by a nut 41, 42 and bolt 43, 44 that extends through coaxially aligned apertures 45, 46, 47, 48 in the adjacent flanges 22, 23, 32, 33 of the two clamping members 20, 30. 25 Each annular clamping member 20, 30 has rectangular cut outs 14, 15, 16, 17 in the wall of the member above the flange on each side. The cut outs 14-17 make the saddle 10 lighter without affecting its strength and operational effectiveness. 30 The profile of the clamping flanges 22, 23, 32, 33 differs from side to side. Thus, as shown in Figure 1 on the right hand side each clamping member has a rectangular 3130266_1 (GHMatters) P86402.AU.1 7/02/12 - 6 flange 22, 32 with a U-shaped central recess 51, 61 defining two clamping surfaces 52, 53, 62, 63 on either side of the recess. The flange 32 of the back strap 30 is similarly profiled in the orientation shown in Figure 1. s On the other hand, on the opposite or left hand side of the saddle 10 the off take 20 and back strap 30 have T shaped flanges 23, 33 defining an upstanding central leg portions 64, 74 that constitutes the abutting surfaces with a pair of planar shoulder portions 65, 66 and 75, 76 10 on either side thereof. The flange 23 of the upper clamping member 20 that is the off take is slightly different in the sense that a small notch 67 is taken out of one arm of the T-shaped flange 54 as shown in Figure 8. 15 The back strap 30 which is shown in greater detail in Figures 15 to 19 has the letter F embossed into one arm of the T-shaped flange 33 on the left hand side as shown in Figure 14 and the letter R embossed into the upper surface of the flange 32 on the right hand side. The off take 20 20 is designed so that it can be attached to the back strap in two orientations namely a first orientation that is shown in Figure 1 in which the U-shaped flanges 51, 52 are in abutting contact and a second orientation (not shown) in which the U-shaped flange is on the left hand side 25 abutting the T-shaped flange 33 of the back strap 30. In either orientation the notch 67 in the top corner of the off take 20 provides visible access to the embossed letter F or letter R so that in the first orientation shown in Figure 1 the letter R is obscured and the letter F is 30 visible and in the second orientation the letter F is obscured by the flange but the letter R is visible. This provides a ready indication of the orientation of the tapping saddle 10. 3130266_1 (GHMatters) P86402.AU.1 7/02/12 - 7 In the orientation shown in Figure 1 where the letter F is exposed the clamp has a fixed diameter suitable for low stiffness orientated PVC pipes. In the second 5 orientation (not shown) the letter R is exposed and the central leg 64 of the T-shaped flange of the off-take locates within the U-shaped recess 61 in the flange 32 of the back strap 30 providing adjustable diameters within a 9mm range, depending on the clamping force which is 10 applied through the fasteners 10, 12. In this arrangement the saddle 10 can be used on rigid pipes such as ductile iron or steel. As shown in Figure 11 the recess 27 in the underside is of the off take 20 is stepped and includes four spaced castellations 79, that is notches in the outer wall. The recess 27 accommodates the gasket 70 shown in Figures 20 to 23. The gasket 70 is moulded in nitride rubber to define an annulus 71 with a central aperture 72 that 20 merges with the periphery in a slightly sloping wall portion 73 so that the thickness of the gasket 70 increases from the periphery to the wall of the aperture 72. This bulkier position of the gasket constitutes a compression force seal. The internal wall of the aperture 25 72 has a triangular shaped groove 74 with a radiused base 85 as shown in Figure 23. The groove 74 defines lips 86, 87 that constitute a hydrostatic force seal. The gasket 70 sits within the recess 27 in the off take 10, as shown in Figure 2 and effectively seals the off take preventing 30 escape of fluid from the pipe past the saddle 10. To install the tapping saddle 10 the pipe surfaces must first be clean and free of soil, mud and scale. The 31302661 (GHMatters) P86402.AU.1 7/02/12 - 8 back strap 30 is then positioned at the desired location on the pipe and depending on whether it is a flexible or rigid pipe the off take 20 is orientated so that the letter F is visible through the notch 67 in the corner or 5 by reversing the off take so that the letter R is visible through the notch 67 in the appropriate corner. The off take is then attached and the washers and nuts hand tightened onto the bolts. Finally, the assembly is tensioned using a torque wrench to a torque of 8ONm. It io is important to ensure that in tensioning the bolts the saddle is not rotated on the pipe. A hole can then be drilled into the pipe through the spigot 25. The gasket provides important sealing features using is both a hydrostatic seal force defined by the inside section of the gasket profile and a compressive seal force caused by the outside section of the profile. The forces produced by these seals achieve a watertight seal. The tapered shape of the gasket profile ensures the lips 86, 20 87 of the hydrostatic seal are wide open and firm against the body of the saddle and the pipe within the saddle. The tapered shape of the gasket increases the force on the compressive section of the gasket 70 as the water forces its way back into the recess. The castellations 79 in the 25 recess 27 ensure that the hydrostatic seal is filled with water and not able to get behind the lips 75, 76 of the seal. When the saddle 10 is installed on a fixed diameter, dry, empty low stiffness pipe the shape and hardness of the gasket prevent the pipe type F pipe from 30 being distorted diametrically more than 5% but achieve sufficient contact with the lips 75, 76 to ensure a watertight seal. As the water pressure increases and the seal 70 is pushed back into the recess 27, the heavier 3130266_1 (GHMatters) P86402.AU.1 7/02/12 -9 solid section 73 of the gasket 70 maintains the hydrostatic seal shape and orientation ensuring a continuing seal. When the saddle 10 is installed in the other orientation on a high stiffness type R pipe it is 5 able to be installed on a range of diameters with a fixed diameter being the largest pipe size down to a diameter reduced by 9mm. For a type R installation the gasket 70 performs in 10 the same manner as detailed for the type F installation. However, when the type R installation is on a pipe with a diameter less than the fixed diameter the saddle does not fit closely to the circumference of the pipe. Instead there is a clearance between the saddle 10 and the pipe 15 starting with no gap in the top adjacent the spigot 25 and bottom of the saddle increasing to a maximum gap adjacent to the clamped sides of the saddle 10. This reduces the compression of the gasket 70 down the side of the pipe. However, the side heavy section 73 of the gasket 70 and 20 the rubber hardness prevent it from being extruded out of the gap and holds the lip seals in position ensuring that watertight seal is maintained. In the claims which follow and in the preceding 25 description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but 30 not to preclude the presence or addition of further features in various embodiments of the invention. 3130266_1 (GH Matters) P86402.AU.1 7/02/12

Claims (8)

1. A tapping saddle comprising a pair of arcuate bands that when fixed together define a clamp adapted to 5 engage the exterior of a pipe, each band having abutting flanges on either end with fasteners arranged to extend through the flange to clamp the saddle to the exterior of the pipe, each flange having a profile to accommodate a flange of the 10 other band whereby when one band is reversed the diameter of the clamp changes.

2. The tapping saddle according to claim 1 wherein one band has a projecting hollow spigot to define an is off take.

3. The tapping saddle according to either claim 1 or 2 wherein the spigot is internally threaded at an outer end with a recess on an inner end to adapted 20 to accommodate a sealing gasket.

4. The tapping saddle according to anyone of the preceding claims wherein the sealing gasket is an annulus with walls that taper inwardly towards the 25 periphery.

5. The tapping saddle according to claim 4 wherein the inner wall is furnished with a V shaped groove. 30

6. The tapping saddle according to anyone of the preceding claims wherein the bands carry indicators that show the orientation of the bands. 3130266_1 (GHMatters) P86402.AU.1 7/02/12 - 11

7. The tapping saddle according to claim 6 wherein each band has one flange with a male abutment surface and the other with a female abutment surface whereby the bands can be assembled male to 5 male and female to female in one orientation and male to female and male to female in another orientation.

8. A tapping saddle substantially as described herein 10 with reference to and as illustrated in the accompanying drawings. 3130266_1 (GHMatters) P86402.AU.1 7/02/12