Device and method to split pipe near utilities

Abstract

A splitter system and methods are shown. Examples of splitter systems provide limited possibility of damage to adjacent utilities in the ground. Further, examples of splitter systems relax a shape memory of split pipe, which in turn reduces friction in a splitting operation. Configurations are further shown that provide lubrication to splitting operations in a number of locations along a splitter system. Configurations are also shown that provide electrical isolation to cutting blades.

We claim: 
     
         1 . A pipe splitter, comprising:
 a splitter body;   one or more splitting blades coupled to the splitter body;   a shaping mandrel in front of the one or more splitting blades, with a circumferential cavity sized to accommodate one or more interior portions of sheared beads, the circumferential cavity exposed on an exterior surface of the splitter system, and located between the shaping mandrel and the plurality of blades; and   a circumferential cutting blade coupled to the splitter body adjacent to the cavity to shear a portion of a polymer bead at a fused polymer pipe joint.   
     
     
         2 . The pipe splitter of  claim 1 , wherein the one or more splitting blades includes eight blades. 
     
     
         3 . The pipe splitter of  claim 1 , wherein the one or more splitting blades includes multiple blades spaced apart in a regular angular spacing. 
     
     
         4 . The pipe splitter of  claim 1 , wherein the one or more splitting blades includes a plurality of blades that include a cutting depth of approximately 75 percent of a wall thickness of a pipe to be split. 
     
     
         5 . The pipe splitter of  claim 4 , wherein the plurality of blades includes a primary blade having a primary cutting depth that is deeper than the rest of the plurality of blades. 
     
     
         6 . The pipe splitter of  claim 5 , wherein the primary blade includes a cutting depth of approximately 90 percent of the wall thickness. 
     
     
         7 . The pipe splitter of  claim 1 , further including an expander coupled behind the splitter body. 
     
     
         8 . The pipe splitter of  claim 7 , wherein the one or more splitter blades are coupled along a portion of the splitter body with a cylindrical cross section. 
     
     
         9 . The pipe splitter of  claim 7 , wherein the expander includes at least one opening to expel a fluid. 
     
     
         10 . A pipe splitter, comprising:
 a splitter body;   one or more splitting blades coupled to the splitter body;   a shaping mandrel in front of the one or more splitting blades;   a cavity between a front of the splitter body and the shaping mandrel, the cavity sized to accommodate one or more interior portions of sheared beads; and   a forward facing cutting blade coupled to the splitter body adjacent to the cavity, the forward facing cutting blade having an outer edge that is configured to be parallel with an interior of a pipe to be split.   
     
     
         11 . The pipe splitter of  claim 10 , further including an expander coupled behind the splitter body. 
     
     
         12 . The pipe splitter of  claim 11 , wherein the one or more splitter blades are coupled along a portion of the splitter body with a cylindrical cross section. 
     
     
         13 . The pipe splitter of  claim 12 , wherein the expander includes at least one opening to expel a fluid. 
     
     
         14 . A method of splitting a pipe, comprising:
 pulling a splitter body through a pipe;   cutting only a portion of a wall thickness in the pipe in a plurality of angular locations around an inside diameter of the pipe using a plurality of blades, wherein one or more of the plurality of blades includes a maximum cutting depth that is less than the wall thickness of the pipe;   expanding the pipe with an expander to split the pipe; and   pulling in a new pipe behind the expander.   
     
     
         15 . The method of  claim 14 , further including cutting one or more portions of the wall thickness deeper than other portions using a blade from the plurality of blades that is taller than other blades in the plurality of blades. 
     
     
         16 . The method of  claim 14 , wherein cutting only a portion of a wall thickness includes cutting 75 percent of a wall thickness along one or more cutting paths. 
     
     
         17 . The method of  claim 14 , wherein cutting only a portion of a wall thickness includes cutting 90 percent of a wall thickness along one or more cutting paths. 
     
     
         18 . The method of  claim 14 , wherein cutting only a portion of a wall thickness includes cutting 75 percent of a wall thickness along multiple cutting paths and cutting 90 percent of a wall thickness along a single cutting path.