Heat saving apparatus

Claim 2

In a forced draft home heating system comprising a furnace having a return plenum, a supply plenum, fan means for circulating air through an air circulating system including said furnace and said plenums, a combustion chamber, a chimney, a flue communicating therebetween and means for combustion gases to flow through said chamber, flue and chimney, the improvement comprising a heat exchanger interposed along a portion of the length of said flue, said heat exchanger having opposed tapered collars which engage with said flue and connect with a casing of enlarged cross-section extending therebetween, said casing enclosing a plurality of longitudinal tubes extending between opposed end plates from one collar to the other and providing a chamber within said casing and outside of said tubes, openings at opposite ends of said casing, the opening at one end of said casing being connected to a return register in said air circulating system and being separate from said return plenum, and the opening at the other end of said casing being connected to said return plenum to interconnect the existing fan means in said furnace with said return register via said chamber and said return plenum so that some of the air entering the furnace is preheated while the remainder of the air circulating in the system is not preheated.

Claim 3

Apparatus as recited in claim 1 in which the cross-sectional area of said sealed chamber is about the same as the cross-sectional area of said flue.

Claim 4

Apparatus as recited in claim 1 in which a fan provides a forced draft which blows combustion gases through said chamber, tubes and chimney.

Claim 5

In a forced draft home heating system comprising a furnace having a return plenum, a supply plenum, fan means for circulating air thorugh an air circulating system including said furnace and said plenums, a combustion chamber, a chimney, a flue communicating therebetween and means for combustion gases to flow through said chamber, flue and chimney, the improvement comprising a heat exchanger interposed along a portion of the length of said flue, said heat exchanger having opposed collars which engage with said flue and connect with a casing of enlarged cross-section extending therebetween, said casing enclosing a plurality of longitudinal tubes extending between opposed end plates from one collar to the other and proving a chamber within said casing, said tubes having approximately the same cross-sectional area as said flue, openings at opposite ends of said casing, the opening at one end of said casing being connected to said return plenum to interconnect the existing fan means in said furnace with the opening on the other end of said casing via said chamber within said casing and said return plenum so that some of the air entering the furnace is preheated while the remainder of the air circulating in the system is not preheated, said opening on the other end of said casing being separate from said return plenum.

Claim 6

In a forced draft home heating system comprising a furnace having a return plenum, a supply plenum, fan means for circulating air thorugh an air circulating system including said furnace and said plenums, a combustion chamber, a chimney, a flue communicating therebetween and means for combustion gases to flow through said chamber, flue and chimney, the improvement comprising a heat exchanger interposed along a portion of the length of said flue, said heat exchanger having opposed collars which engage with said flue and connect with a casing of enlarged cross-section extending therebetween, said casing enclosing a plurality of longitudinal tubes extending between opposed end plates from one collar to the other and proving a chamber within said casing, said tubes having approximately the same cross-sectional area as said flue, openings at opposite ends of said casing, the opening at one end of said casing being connected to said return plenum to interconnect the existing fan means in said furnace with the opening on the other end of said casing via said chamber within said casing and said return plenum so that some of the air entering the furnace is preheated while the remainder of the air circulating in the system is not preheated, said opening on the other end of said casing being separate from said return plenum.

Claim 7

Apparatus as recited in claim 4 in which blower means are provided to blow combustion gases through said chamber, flue and chimney.