Undercabinet electric space heater unit

Claim 1

AN UNDERCABINET HOT WATER HEATER OF THE TYPE UTILIZING FORCED AIR FLOW OVER A HEAT EXCHANGER IN WHICH ELECTRICAL HEATING INDUCES THE CIRCULATION OF HEATED LIQUID, COMPRISING A CABINET HAVING TOP AND BOTTOM HORIZONTAL WALLS AND WHOSE HEIGHT IS ITS LEAST DIMENSION, A FIRST LATERAL HORIZONTAL TUBE SUPPORTED THEREIN SPACEDLY ABOVE THE BOTTOM AND BELOW THE TOP OF THE FRAME, AN ELECTRICAL RESISTANCE HEATER WITHIN SAID FIRST TUBE, MEANS PROVIDING A PATH FOR THE FLOW OF LIQUID THROUGH SAID TUBE AND AROUND SAID HEATER, SAID MEANS INCLUDING A SECOND LATERAL HORIZONTAL TUBE OF SMALLER DIAMETER AND WHOSE TUBE AXIS IS ABOVE THE LEVEL OF SAID FIRST TUBE, AND AFT-EXTENDING, UPWARD-SLOPING TUBULAR CONNECTIONS BETWEEN SAID FIRST AND SECOND TUBE ADJACENT TO THEIR ENDS, HEAT-CONDUCTIVE VERTICAL FINS AFFIXED TO AND ALONG THE LENGTH OF SAID SECOND TUBE INTERMEDIATE SAID TUBULAR CONNECTIONS, AIR-IMPELLING MEANS, AND MEANS TO LATERALLY CONFINE THE AIR IMPELLED THEREBY TO THE FINNED LENGTH OF THE SECOND TUBE, WHEREBY TO DEFINE, IN PART, WALLS OF A PLENUM CHAMBER IN WHICH THE FINNED LENGTH OF THE SECOND TUBE IS AT THE OUTLET AND THE FIRST TUBE EXTENDS ACROSS THE ENTIRE LENGTH THEREOF, THE CABINET FURTHER HAVING A FRONT REGISTER-CONTAINING WALL INCLUDING AN INLET REGISTER COMMUNICATING TO THE AIR-IMPELLING MEANS, AND AN OUTLET REGISTER SIDEWARD OF THE INLET REGISTER, AND AN OUTLET PASSAGE FROM THE FINNED TUBE TO THE OUTLET REGISTER.