Compressor or Gas Extraction System

Abstract

A compressor capable of cooling an electric motor which drives a compressor impeller even in an environment where no external refrigerant is obtained is to be provided. A compressor includes: an electric motor; an impeller which rotates with rotation of the electric motor; a main flow path formed downstream of the impeller, and a bypass flow path branching off from the main flow path; a heat exchange unit which is arranged upstream of the impeller and where gas upstream of the impeller and gas inside the bypass flow path exchange heat; and a pressure reducing device which is arranged further downstream than the heat exchange unit with respect to the bypass flow path and situated inside a flow path communicating with the inside of the electric motor.

1 . A compressor comprising:
 an electric motor;   an impeller which rotates with rotation of the electric motor;   a main flow path formed downstream of the impeller, and a bypass flow path branching off from the main flow path;   a heat exchange unit which is arranged upstream of the impeller and where gas upstream of the impeller and gas inside the bypass flow path exchange heat; and   a pressure reducing device which is arranged further downstream than the heat exchange unit with respect to the bypass flow path and situated inside a flow path communicating with the inside of the electric motor.   
     
     
         2 . A compressor comprising:
 an electric motor;   an impeller which rotates with rotation of the electric motor;   a main flow path formed downstream of the impeller, and a splitting unit which extracts a part of gas from the main flow path;   a heat exchange unit which is arranged upstream of the impeller and where gas upstream of the impeller and a split gas extracted by the splitting unit exchange heat; and   a pressure reducing device which reduces pressure of the split gas cooled by the heat exchange unit;   the electric motor being cooled by the split gas having the pressure reduced by the pressure reducing device.   
     
     
         3 . The compressor according to  claim 1 , comprising a filtering device inside the bypass flow path. 
     
     
         4 . The compressor according to  claim 3 , wherein the filtering device is arranged downstream of the heat exchange unit inside the bypass flow path. 
     
     
         5 . The compressor according to  claim 4 , wherein the filtering device also functions as the pressure reducing device. 
     
     
         6 . The compressor according to  claim 3 , wherein the filtering device is a cyclone separator. 
     
     
         7 . The compressor according to  claim 1 , wherein the heat exchange unit has a structure in which a pipe forming a part of the bypass flow path is spirally wound. 
     
     
         8 . The compressor according to  claim 7 , further comprising an outer casing that covers an outer peripheral side of the impeller,
 wherein the heat exchange unit has a structure in which the pipe is spirally wound on the outer casing.   
     
     
         9 . A gas extraction system comprising:
 the compressor according to  claim 1 ;   a power supply device which is a motive power of the compressor; and   a power cable which supplies electric power from the power supply device to the compressor;   the compressor being installed inside a gas well which guides gas from an underground gas reservoir to a ground surface.