Thermal contraction compensation for superconducting and cryo-resistive cables

Abstract

A cable insertion tool for installing thermally compensated superconducting and cryo-resistive cables is disclosed. The cable insertion tool includes a guide tube adapted to engage a pipe and to prevent a cable positioned therein from buckling, a cross-bar adapted to move along the guide tube and engage an end of the cable positioned therein, and a cable drive apparatus operably connected to the cross-bar. The cable drive apparatus is adapted to move the cross-bar such that the cable positioned in the guide tube is forced into the pipe.

We claim: 
     
         1 . A cable insertion tool, comprising:
 (a) a guide tube adapted to engage a pipe and to prevent a cable positioned therein from buckling;   (b) a cross-bar adapted to move along the guide tube and engage an end of the cable positioned therein; and   (c) a cable drive apparatus operably connected to the cross-bar, the cable drive apparatus being adapted to move the cross-bar such that the cable positioned in the guide tube is forced into the pipe.   
     
     
         2 . The cable insertion tool according to  claim 1 , further including an end plate adapted to rest adjacent to a flange of the pipe. 
     
     
         3 . The cable insertion tool according to  claim 1 , wherein the cable drive apparatus includes a first connector extending between a first end of the cross-bar and a first piston of a first ram and a second connector extending between a second end of the cross-bar and a second piston of a second ram. 
     
     
         4 . The cable insertion tool according to  claim 3 , wherein the first and second rams are hydraulically powered. 
     
     
         5 . The cable insertion tool according to  claim 3 , wherein the first and second rams are pneumatically powered. 
     
     
         6 . The cable insertion tool according to  claim 1 , wherein the cable drive apparatus includes a first chain extending between a first end of the cross-bar and a first ratchet and a second chain extending between a second end of the cross-bar and a second ratchet. 
     
     
         7 . The cable insertion tool according to  claim 6 , wherein the first and second ratchets each include a sprocket and a pawl. 
     
     
         8 . The cable insertion tool according to  claim 1 , wherein the cable drive apparatus includes a first pulley connected to a first end of the cross-bar, a second pulley connected to a first end of an end plate, a third pulley connected to a second end of the cross-bar, and a fourth pulley connected to a second end of the end plate. 
     
     
         9 . The cable insertion tool according to  claim 8 , wherein a first rope extends between and around the first pulley and the second pulley and a second rope extends between and around the third pulley and the fourth pulley. 
     
     
         10 . The cable insertion tool according to  claim 1 , wherein the cable drive apparatus includes a first rack driven by a first pinion and a second rack driven by a second pinion, the first rack being connected to a first end of the cross-bar and the second rack being connected to a second end of the cross-bar. 
     
     
         11 . The cable insertion tool according to  claim 10 , wherein the first pinion is driven by a first drive means and the second pinion is driven by a second drive means. 
     
     
         12 . The cable insertion tool according to  claim 11 , wherein the guide tube includes a flared end to protect the cable from excessive bending.