US4015932A — Combustion air preheater

Claim 1

Independent Claim 202 words

A combustion air preheater for recovering exhaust heat from an enclosure forming at least part of a flue of a furnace and supplying heated air to a burner of the furnace, comprising: a cylindrical preheater pipe having an inlet end and an outlet end, means for mounting the preheater pipe in said enclosure with the inlet and outlet ends of the pipe located externally of the enclosure, air inlet means connected to the inlet end of the preheater pipe for introducing air thereto in a direction generally transverse and tangential to the longitudinal axis thereof, said air inlet means comprising a housing having an outlet opening connected to the inlet end of the preheater pipe and aligned axially therewith, said housing having an inlet opening directed transversely to the axis of the outlet opening and spaced radially outward of said axis, and a generally cylindrical baffle defining an annular passage communicating tangentially with the inlet opening and axially with the outlet opening; an air passage connecting the outlet end of the preheater pipe to the burner, and control means operatively associated with said air passage for regulating at least one physical property of air supplied to the burner through said air passage.

Claim 2

Dependent Claim 202 words

A combustion air preheater for recovering exhaust heat from an enclosure forming at least part of a flue of a furnace and supplying heated air to a burner of the furnace, comprising: a cylindrical preheater pipe having an inlet end and an outlet end, means for mounting the preheater pipe in said enclosure with the inlet and outlet ends of the pipe located externally of the enclosure, air inlet means connected to the inlet end of the preheater pipe for introducing air thereto in a direction generally transverse and tangential to the longitudinal axis thereof, said air inlet means comprising a housing having an outlet opening connected to the inlet end of the preheater pipe and aligned axially therewith, said housing having an inlet opening directed transversely to the axis of the outlet opening and spaced radially outward of said axis, and a generally cylindrical baffle defining an annular passage communicating tangentially with the inlet opening and axially with the outlet opening; an air passage connecting the outlet end of the preheater pipe to the burner, and control means operatively associated with said air passage for regulating at least one physical property of air supplied to the burner through said air passage.

Claim 3

Dependent Claim 58 words

A combustion air preheater according to claim 1 wherein said furnace includes structure supporting and forming a chamber enclosed by side walls, front and rear walls and a roof wall, one of said walls having an opening therein for the passage of flue gases, and said enclosure is mounted on said furnace structure in communication with said opening.

Claim 4

Dependent Claim 77 words

A combustion air preheater according to claim 1, wherein said furnace includes a front wall, a slot in the front wall for the loading and unloading of workpieces, said slot also serving as a passage for flue gases from the furnace, and a preheater unit attached to the furnace and having wall means arranged to form the enclosure in combination with the front wall of the furnace, the enclosure being located outwardly of and above the slot.

Claim 5

Dependent Claim 52 words

A combustion air preheater according to claim 3 wherein the enclosure includes a bottom shelf projecting outwardly from the front wall of the furnace and spaced below at least a portion of the wall means of the preheater unit to provide a workpiece loading and unloading opening substantially aligned with the slot.

Claim 6

Dependent Claim 21 words

A combustion air preheater according to claim 4 further including means for introducing a coolant to the enclosure through said opening.

Claim 7

Dependent Claim 21 words

A combustion air preheater according to claim 1 wherein said control means includes a vent valve connecting said passage to atmosphere.

Claim 8

Dependent Claim 30 words

A combustion air preheater according to claim 6 including means for controlling the setting of said vent valve in response to the temperature of the preheated air in said passage.

Claim 9

Dependent Claim 20 words

A combustion air preheater according to claim 1 wherein said control means includes a flow control valve in said passage.

Claim 10

Dependent Claim 27 words

A combustion air preheater according to claim 8 including means for controlling the setting of said flow control valve in response to the temperature in the furnace.

Claim 11

Dependent Claim 206 words

A combustion air preheater unit for use with a slot furnace having a burner and a front wall with a slot through which exhaust gases escape and workpieces are loaded and unloaded, said unit comprising: structure providing three-sided wall means adapted to be mounted adjacent to said front wall and form therewith an insulated enclosure, said wall means including an outer wall spaced from said front wall and a pair of side walls each extending between said outer wall and front wall, a removable bulkhead provided in one of said side walls, and said outer wall having a lower portion; a cylindrical air preheater pipe carried by the side walls of said structure and having an inlet end, an outlet end, and at least one convolution between said ends, at least one end of said preheater pipe extending through said removable bulkhead, and supporting means carried by at least one of said side walls for slidably supporting said pipe at the convolution therein; and, a bottom wall projecting outwardly from said front wall of the furnace below said slot and below said lower portion of said outer wall to provide an opening aligned with said slot for the loading and unloading of workpieces through said slot.

Claim 12

Dependent Claim 206 words

A combustion air preheater unit for use with a slot furnace having a burner and a front wall with a slot through which exhaust gases escape and workpieces are loaded and unloaded, said unit comprising: structure providing three-sided wall means adapted to be mounted adjacent to said front wall and form therewith an insulated enclosure, said wall means including an outer wall spaced from said front wall and a pair of side walls each extending between said outer wall and front wall, a removable bulkhead provided in one of said side walls, and said outer wall having a lower portion; a cylindrical air preheater pipe carried by the side walls of said structure and having an inlet end, an outlet end, and at least one convolution between said ends, at least one end of said preheater pipe extending through said removable bulkhead, and supporting means carried by at least one of said side walls for slidably supporting said pipe at the convolution therein; and, a bottom wall projecting outwardly from said front wall of the furnace below said slot and below said lower portion of said outer wall to provide an opening aligned with said slot for the loading and unloading of workpieces through said slot.

Claim 13

Dependent Claim 38 words

A combustion air preheater unit according to claim 10 further including air inlet means for introducing air to the inlet opening of the air preheater pipe in a direction tangential and generally transverse to the longitudinal axis thereof.

Claim 14

Dependent Claim 51 words

A combustion air preheater unit according to claim 11 further including an air passage connecting the outlet opening of the air preheater pipe to the burner, and control means operatively associated with said air passage for regulating at least one physical property of air supplied to the burner through said passage.

Claim 15

Dependent Claim 27 words

A combustion air preheater unit according to claim 11 further including means for introducing a coolant to said flue below the level of the air preheater pipe.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-04-04	1980-10-04	1981-04-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-04-04	1984-10-04	1985-04-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-04-04	1988-10-04	1989-04-05	$7700.00	Window Closed / Lapsed

Combustion air preheater

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