Detection of leaks in heat exchangers

Abstract

A method for detection of leaks in a plate pack heat exchanger having respective discrete first and second flow paths in mutual thermal contract comprises connecting a helium detector probe at one end of the first flow path and an air compressor means at the other end of the first flow path, introducing helium to the second flow path, allowing air to pass through the first flow path under the influence of the compressor means and detecting any helium present therein by the helium detector probe, the pressure of the second flow path being higher than that of the first flow path.

1 . A method for detection of leaks in a plate pack heat exchanger ( 10 ) having respective discrete first ( 13 ,  22 ) and second ( 12 ,  16 ) flow paths in mutual thermal contact, the method comprising connecting a helium detector probe ( 26 ) at one end of said first flow path and an air compressor means ( 24 ) at the other end of said first flow path, said first flow path being open to atmosphere at each end, introducing helium to said second flow path, allowing air to pass through said first flow path under the influence of the compressor means and detecting any helium present therein by the helium detector probe, the pressure of the second flow path being higher than that of the first flow path.  
     
     
         2 . A method according to  claim 1 , in which the air compressor ( 24 ) operates at a pressure sufficient to drive air at from 15 to 30 cu. ft./min. through the first flow path against an outlet of atmospheric pressure.  
     
     
         3 . A method according to  claim 1  or  claim 2 , in which the second flow path ( 12 ,  16 ) is substantially emptied of liquid before introduction of helium therein.  
     
     
         4 . A method according to  claim 1  or  claim 2 , in which both flow paths are substantially emptied of liquid.  
     
     
         5 . A method according to any preceding claim, in which the second flow path ( 12 ,  16 ) is also open-ended.  
     
     
         6 . A method according to  claim 5 , in which the second flow path ( 12 ,  16 ) is provided with a flow restrictor or throttle ( 18 ) at the downstream end.  
     
     
         7 . A method according to any preceding claim, in which the pressure at which the helium is introduced does not exceed 20 psig.  
     
     
         8 . A method according to any preceding claim, in which the helium detector probe ( 26 ) detects helium present in the first flow path ( 13 ,  22 ) on the basis of thermal conductivity.  
     
     
         9 . A heat exchanger ( 10 ) comprising discrete first ( 13 ,  22 ) and second ( 12 ,  16 ) flow paths in mutual thermal contact, said first flow path being open to atmosphere at each end, the heat exchanger including a helium detector probe ( 26 ) at one end of said first flow path and an air compressor means ( 24 ) at the other end of said first flow path and a source of helium ( 14 ) connected to said second flow path.  
     
     
         10 . A heat exchanger according to  claim 9 , including means ( 18 ) to maintain the pressure in said second flow path higher than the pressure in said first flow path.