Patent Application
20080011358
In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are employed to indicate like parts in the various views:
Referring now in more detail to the drawing figures, and initially to
For instance, as illustrated in
With continued reference to
Each secondary passageway 40 is configured for receiving therein a cutting element 52 that may be rotationally driven towards the respective intake port 42 to eventually reach the transmission line structural wall 102 when the tapping assembly 10 is coupled to the transmission line 100. In this way, the secondary passageways 40 largely serve to guide the movement of cutting elements 52 towards the respective intake ports 42 to generate radially-extending cutouts 106 in the structural wall 102 of the transmission line 100, while the primary passageway 38 functions as the continuous flow pathway for flowable material (i.e., natural gas, water, etc.) from the transmission line 100 through the manifold 36 to an attachment point for a service line at the branch outlet 12. Specifically, with reference to
As seen in
The saddle fitting 14 is preferably shaped around the manifold 36 such that a branch stem 74 establishes the main conduit section 48 of the primary passageway 38 and a set of tapping stems 76 each establishing one of the secondary passageways 40. In this way, the branch stem 74 terminates at the branch outlet 12 and each tapping stem 76 terminates at one of the tapping outlets 50. A sealing cap 78 having an internally threaded collar 80 is received by mating threads 82 on the outer surface 84 of each of the tapping stems 76. The sealing cap 78 serves to seal off the tapping outlets 50 of the set of secondary passageways 40 once the tapping sequence with the cutting elements 52 is complete, ensuring that flow through the manifold 36 is directed from the intake ports 42 through the primary passageway 38 and out through the branch outlet 12. In an alternative arrangement, the collar 80 of each sealing cap 78 may have external threads for engaging with the internal threaded section 66 of one of the secondary passageways 40 above the respective cutting element 52, such that the collar 80 is received within the tapping stem 76.
After the tapping assembly 10 is initially secured onto a section of the transmission line 100 by the split collar 18, the region surrounding each intake port 42 on the mating surface 24 of the saddle fitting base 20 needs to be sealed with the outside surface 104 of the transmission line structural wall 102. This ensures that flow leaving one of the cutouts 106 in the structural wall 102 moves directly into the respective intake port 42 and into the manifold 36 without leaking through any gap between the mating surface 24 of the saddle fitting base 20 and the outside surface 104 of the structural wall 102. Accordingly, sealing of the mating surface 24 with the outside surface 104 of the transmission line structural wall 102 may be made by various means, such as by the use of a solvent, cement, glues (e.g., PVC glue for a transmission line 100 and saddle fitting 14 formed of PVC), or other arrangements. As one example, a o-ring may be placed within an annular recess (not shown) in the mating surface 24 surrounding each intake port 42 to seal against the outside surface 104 of the structural wall 102. In still another example, electrofusion may be utilized to seal the mating surface 24 with the structural wall outside surface 104. With electrofusion, a heating element (not shown) formed by conductive pathway on the mating surface 24 surrounding each intake port 42 causes melt fusion between the surfaces 24 and 104 in the region surrounding the intake port 42.
By configuring the primary passageway 38 with opposed lateral conduit sections 46 extending from multiple intake ports 42 to the main conduit section 48, a flow path is created that avoids significant pressure drops between the cutouts 106 in the transmission line 100 and the branch outlet 12 where a service line connects. As one exemplary configuration, a transmission line 100 having a 2 inch outer diameter may be tapped by the tapping assembly 10 including a pair of cutting elements 52 each having a working blade 56 sized to form a 1 and ⅛ inch cutout 106 in the transmission line 100. Additionally, the intake ports 42 and the lateral conduit sections 46 of the primary passageway 38 are sized to maintain a diameter at least as large as the cutout 106 diameter, in this case a 1 and ⅛ inch diameter, while the main conduit section 48 has a 2 inch diameter to match the internal diameter of a service line to be coupled with the branch outlet 12. This configuration serves to minimize pressure drop through the manifold 36 while providing the desired amount of flow to the service line. Those of skill in the art will appreciate, however, that other dimensions may be selected in order to maintain adequate flow through the manifold 36 based on a given diameter of a selected transmission line 100. In any case, the tapping assembly 10 provides significantly improved flow for a sidewall tapping tee where the diameter of the service line to be connection approaches the diameter of the transmission line.
With a traditional tapping tee, forming a cutout 106 with a diameter approaching the size of the outer diameter of the transmission line 100, if even possible, would seriously affect the structural integrity of the transmission line 100 and any bond formed between the mating surface 24 and the outside surface 104 of the structural wall 102. The tapping tee 10 of the present invention avoids this problem by providing multiple, smaller diameter cutouts 106 and a manifold 36 configured to provide flow to the branch outlet 12 and connected service line that is equivalent to flow that would be realized through one larger cutout 106 if the transmission line 100 had been sized adequately to support such a large cutout. Furthermore, by utilizing a saddle fitting 14 that is unitary in nature, the tapping assembly 10 functioning as a multiple cutter tapping tee can be initially coupled to a transmission line 100 (i.e., prior to sealing or fusing the base 20 with the outside surface 104) in essentially one step. In one embodiment, the unitary saddle fitting 14 and free collar member 22 are each formed by molding a polymeric material, such as one or more plastics and the like. The cutting elements 52 may be formed from various materials having a hardness greater than the hardness of the polymeric transmission line 100. For instance, the cutting elements 52 may be formed from solid brass or other metals. It should also be understood that additional secondary passageways 40 and corresponding cutting elements 52 and intake ports 42 may be provided for each primary passageway 38 and branch outlet 12 in the saddle fitting 14.
Turning to
As can be understood, the tapping assembly 10 of the present invention provides a self-contained unit for creating an adequately sized flow junction between a polymeric transmission line 100 and a service line. The tapping assembly 10 also has a decreased likelihood of being damaged by excavation activities in a subterranean installation as compared to traditional sidewall taping tees.
Furthermore, since certain changes may be made in the above invention without departing from the scope hereof, it is intended that all matter contained in the above description or shown in the accompanying drawing be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are to cover certain generic and specific features described herein.
