Drain arrangement for heat recovery unit

Abstract

There is provided a gas heat recovery unit comprising: two gas flow paths in heat exchange contact; a condensate drainage path for each of said two gas flow paths for draining condensate from the respective gas flow path, said two condensate drainage paths being fluidly connected to a common drainage outlet of the heat recovery unit; and each of said two condensate drainage paths comprising a valve which allows passage of liquid but not gas from the respective gas flow path towards the common drainage outlet. Providing a common drainage outlet simplifies installation and minimises the possibility of incorrect installation. It also permits switching the airflows within the unit without requiring any corresponding alteration to the drainage system.

1 . A gas heat recovery unit comprising:
 two gas flow paths in heat exchange contact;   a condensate drainage path for each of said two gas flow paths for draining condensate from the respective gas flow path, said two condensate drainage paths being fluidly connected to a common drainage outlet of the heat recovery unit; and   each of said two condensate drainage paths comprising a valve which allows passage of liquid but not gas from the respective gas flow path towards the common drainage outlet.   
     
     
         2 . A gas heat exchanger unit as claimed in  claim 1 , wherein the valves each comprise a float valve. 
     
     
         3 . A gas heat exchanger unit as claimed in  claim 2 , wherein the float valve comprising a ball float. 
     
     
         4 . A gas heat exchanger as claimed in  claim 2 , wherein the float valve comprises a float in an open vertical tube. 
     
     
         5 . A gas heat exchanger as claimed in  claim 4 , wherein each drainage path further comprises a liquid trap. 
     
     
         6 . A gas heat exchanger as claimed in  claim 2 , wherein each float valve comprises a float in a short vertical tube, the tube being capped at the top. 
     
     
         7 . A gas heat exchanger as claimed in  claim 6 , wherein the tube has a removable cap. 
     
     
         8 . A gas heat exchanger as claimed in  claim 2 , wherein each float valve comprises a valve seat, a float positioned above the valve seat and a cover positioned over the float. 
     
     
         9 . A gas heat exchanger as claimed in  claim 8 , wherein the cover is in the form of a tube closed at the upper end. 
     
     
         10 . A gas heat exchanger as claimed in  claim 8 , wherein the cover is made from foam, preferably expanded polystyrene. 
     
     
         11 . A gas heat exchanger as claimed in  claim 1 , wherein both valves feed into a collection tray which directs condensate towards the common drainage outlet.