Heat recovery system

A heat recovery device for recovering waste heat from a hot gas that carries solid and precipitable contaminants, comprising:

• two pairs of heat exchangers each having spaced essentially vertical first passages therethrough for said hot gas and spaced second passages therethrough for a cooler second gas to be heated by said hot gas, said passages being in heat exchange relationship with each other, said first and second passages comprising interleaved cross flow path means for said gases;
• heat transfer fin means in each said cross flow path means;
• first conduit means for said hot gas to said first passages, said first conduit means having a transverse open frame;
• second conduit means for said second gas leading to said second passages in said heat exchangers;
• third conduit means for removing said second gas from said second passages;
• a filter and contaminant separator unit in said first conduit at the entrance to said first passages;
• and means comprising said transverse open frame for mounting said filter and contaminant separator unit in said first conduit for ready removal from said first conduit and for alternately mounting a liquid receiving container in said first conduit for receiving cleaning liquid introduced into said first passages for periodic cleaning of said first passages of said heat exchangers of said solid and precipitated contaminants deposited in said first passages, each of said pairs of said heat exchangers being arranged for successive flow and with means for dividing said hot gas flow into a pair of streams each passing through a said pair of successive said heat exchangers, thereby permitting continuous operation through one pair while the other, out of service, pair is being cleaned.