Apparatus for recovery of heat from exhaust gases of dryer

Claim 1

Apparatus for recovery of heat in a laundry dryer having a heat chamber means, a drying chamber, a lint removal chamber, and an exhaust conduit, comprising: heat exchange means positioned in said exhaust conduit, said heat exchange means including a plurality of tubes open to a source of fresh air at one end thereof, means securing said tubes in spaced apart, substantially parallel staggered relation transverse to flow of heated exhaust gases through said exhaust conduit and preventing escape of said exhaust gases from said exhaust conduit, a helically twisted elongated strip inside each said tube; suction fan means adjacent the other ends of said plurality of tubes to draw fresh air through said tubes, said fresh air being heated in transit by said exhaust gases; plenum means surrounding said fan means and communicating with said other ends of said tubes for receiving said fresh air drawn therethrough while preventing intermingling of said exhaust gases therewith; conduit means communicating with said plenum means for conducting said heated fresh air into said heat chamber means or into said drying chamber of said dryer; first damper means in said exhaust conduit regulating the flow of exhaust gases therethrough; and second damper means in said conduit means regulating the flow of heated fresh air therethrough.