Screw Compressor

Abstract

A screw compressor includes a compressor body and a shell and tube heat exchanger for cooling of a compressed air discharged from the compressor body. A tube provided in the shell and tube heat exchanger has both ends each having a cylindrical shape, and a center part formed as a multi-lobate tube to have a corrugated shape with crest portions and trough portions alternately arranged in a circumferential direction. The multi-lobate tube provided at the center part of the tube is formed to have a multi-lobate spiral shape through twisting. Size reduction of the shell and tube heat exchanger may make the screw compressor compact as a whole.

What is claimed is: 
     
         1 . A screw compressor comprising:
 a compressor body; and   a shell and tube heat exchanger for cooling of a compressed air discharged from the compressor body, wherein a tube provided in the shell and tube heat exchanger has both ends each having a cylindrical shape, and a center part formed as a multi-lobate tube to have a corrugated shape with crest portions and trough portions alternately arranged in a circumferential direction.   
     
     
         2 . The screw compressor according to  claim 1 , wherein:
 the shell and tube heat exchanger includes a cylindrical shell, headers provided at both ends of the shell, a flange attached to one end of the shell to separate an inside of the shell from one of the headers fluid-tightly, a tube plate attached to the other end of the shell to separate the inside of the shell from the other of the headers fluid-tightly, a plurality of the tubes attached to the flange and the tube plate so as to communicate with the headers provided at the both ends of the shell, and a plurality of baffle plates provided at intervals in the shell in a longitudinal direction, which have through holes through which the tubes penetrate, and guide a fluid introduced into the shell from the one side to the other side of the headers while forming a meander flow of the fluid.   
     
     
         3 . The screw compressor according to  claim 1 , wherein a part of the multi-lobate tube provided at the center part of the tube is formed to have a multi-lobate spiral shape through twisting. 
     
     
         4 . The screw compressor according to  claim 1 , wherein an outer diameter of the part of the multi-lobate tube of the tube is smaller than each outer diameter of cylindrical parts at both ends of the tube. 
     
     
         5 . The screw compressor according to  claim 2 , wherein an inner diameter of the through hole formed in the baffle plate is larger than the outer diameter of the part of the multi-lobate tube in a state where an internal pressure acts on an inside of the tube by operating the compressor.