Method and apparatus for removing a pipe lining

Abstract

An apparatus for removing a lining from a pipe includes a collapsible stripping tool having a plurality of extensible arms with an abrading tool mounted on each arm that is deployed by inserting the apparatus into the pipeline, supplying pressurized fluid to a cylinder to extend the arms and force the abrading tools into engagement with the lining and rotating and pulling the tool down the pipe without destroying the pipe.

1 . A method of removing a lining from an underground pipe, comprising: 
 mechanically fragmenting the lining without destroying the underground pipe by removing substantially all loose portions of the lining along a length of the underground pipe; and    removing resulting lining fragments from the pipe.    
   
   
       2 . The method of  claim 1 , wherein the lining comprises a tubular layer of plastic bonded to an inner peripheral surface of the underground pipe, and the loose portions comprise portions of the plastic layer weakly bonded or unbonded to the inner peripheral surface of the underground pipe.  
   
   
       3 . The method of  claim 2 , further comprising relining the underground pipe along the length of the underground pipe to be relined after the lining fragments have been removed.  
   
   
       4 . A method of removing a lining from an underground pipe, comprising: 
 moving a stripping tool axially through the inside of the pipe; and    operating the stripping tool in a manner effective to substantially remove the lining without destroying the underground pipe.    
   
   
       5 . The method of  claim 4 , wherein the stripping tool comprises a mechanism that rotates the stripping tool along the inside of the pipe so that the tool engages and fragments the lining.  
   
   
       6 . The method of  claim 5 , wherein the stripping tool is forcibly urged in a radial direction against the inside of the pipeline as it rotates.  
   
   
       7 . The method of  claim 5 , wherein the stripping tool is pulled through the pipeline as the stripping tool rotates.  
   
   
       8 . The method of  claim 6 , wherein the stripping tool is pulled through the pipeline as the stripping tool rotates and forcibly engages the inside of the pipeline.  
   
   
       9 . The method of  claim 5 , wherein the stripping tool comprises a stiff wire brush.  
   
   
       10 . The method of  claim 5 , wherein the stripping tool comprises a serrated scraper blade.  
   
   
       11 . The method of  claim 5 , wherein the stripping tool comprises a series of knife blades mounted in a common frame.  
   
   
       12 . The method of  claim 4 , wherein the lining comprises a tubular layer of plastic.  
   
   
       13 . The method of  claim 6 , wherein the stripping tool comprises a plurality of stripping assemblies connected to a central shaft that is coaxial with the pipe.  
   
   
       14 . The method of  claim 13 , further comprising extending the stripping assemblies in a radial direction away from the shaft and into engagement with the inside of the pipe.  
   
   
       15 . A collapsible rotary apparatus for removing material from the inside of a pipe, the apparatus being configured to rotate inside the pipe as the apparatus is pulled through the pipe, comprising: 
 a shaft;    at least one arm mounted on the shaft;    an extension and retraction mechanism connected to the arm which moves the arm in a radial direction, which mechanism includes at least one pivot about which the arm moves during extension and retraction; and    an abrading tool mounted on the arm in a position for circular movement along the inside of the pipe upon rotation of the shaft, wherein radial extension of the arm from a collapsed position to an extended position using the extension and retraction mechanism moves the abrading tool against the inside of the pipe.    
   
   
       16 . The apparatus of  claim 15  further comprising a cylinder connected to extending the extensible arms and maintain the scraping tools in contact with the inside of the pipe under a force applied by the cylinder.  
   
   
       17 . The apparatus of  claim 15  further comprising a plurality of extensible arms mounting abrading tools thereon coupled to the shaft at spaced intervals around the circumference of the shaft.  
   
   
       18 . The apparatus of  claim 15  wherein the abrading tool comprises one of a brush, knife and scraper.  
   
   
       19 . The apparatus of  claim 17  wherein at least one of the arms is axially offset from the adjacent arms.