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US4408594A Expired / Lapsed US ⏱️ 0.0 years remaining

Fireplace heated grate

Assignee: HEARTH TECHNOLOGIES Inc
•
Filing: 1981-05-04
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Granted: 1983-10-11
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Expires: 2001-05-04
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Abstract

Abstract A hollow heated grate for a fireplace is provided with an electric motor and a blower inside of the heated fireplace enclosure for circulating cool air from the area to be heated through the hollow grate and returning the heated air to the area to be heated. The electric motor and blower are physically enclosed in a metal plenum box. To avoid overheating the electric motor windings, cool air is circulated over the motor windings when the electric motor is running and cool air is also circulated over the electric motor windings when the electric motor is not running by novel diversionary air vent means including sensing means for opening a movable closure adjacent the diversionary air vent when the electric motor and blower are not circulating cool air.

Inventors

  • 👤 Ronald J. Shimek
  • 👤 Daniel C. Shimek

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 17:40
CPC Classifications
F; F24; F24B; F24B1/00; F24B1/18; F24B1/185; F24B1/188; F24B1/1885; F24B1/1886

Claims Analysis

Total Claims: 14
Claim 1
Independent Claim 182 words
A plenum for cooling an electric motor in a fireplace enclosure environment, comprising: a box shaped plenum adapted to be placed in a heated fireplace, an electric motor mounted in said plenum, a blower connected to said electric motor in said plenum, an inlet to said blower inside said plenum, an outlet port in said plenum, an outlet from said blower connected to said outlet port in said plenum, a cool air inlet port in said plenum, a diversionary air vent in said plenum located at an elevation above said cool air inlet port, said diversionary vent comprising a normally open movable closure, said movable closure adapted to be opened when said electric motor and said blower are not circulating cool air through said plenum, and means for closing said movable closure when said electric motor and said blower are circulating cool air through said plenum, whereby cool air is circulated from said cool air inlet port through said diversionary air vent when said plenum is hot, thus creating convection cooling of said electric motor when said electric motor is not running.
Claim 2
Dependent Claim 182 words
A plenum for cooling an electric motor in a fireplace enclosure environment, comprising: a box shaped plenum adapted to be placed in a heated fireplace, an electric motor mounted in said plenum, a blower connected to said electric motor in said plenum, an inlet to said blower inside said plenum, an outlet port in said plenum, an outlet from said blower connected to said outlet port in said plenum, a cool air inlet port in said plenum, a diversionary air vent in said plenum located at an elevation above said cool air inlet port, said diversionary vent comprising a normally open movable closure, said movable closure adapted to be opened when said electric motor and said blower are not circulating cool air through said plenum, and means for closing said movable closure when said electric motor and said blower are circulating cool air through said plenum, whereby cool air is circulated from said cool air inlet port through said diversionary air vent when said plenum is hot, thus creating convection cooling of said electric motor when said electric motor is not running.
Claim 3
Dependent Claim 22 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure comprises an electric solenoid means.
Claim 4
Dependent Claim 21 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure comprises spring closure means.
Claim 5
Dependent Claim 30 words
A motor plenum as set forth in claim 3 wherein said spring closure means further comprises a damper lever located in the outlet from said blower to said outlet port.
Claim 6
Dependent Claim 36 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure further includes bi-metallic spring means biased to open said movable closure when the air in said plenum is hot.
Claim 7
Dependent Claim 39 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure comprises a mechanical thermostat coupled to open said movable closure when the temperature in the said plenum rises above 140° degrees fahrenheit.
Claim 8
Dependent Claim 51 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure comprises a temperature sensitive element which opens said movable closure indicating that the electric motor is not properly circulating air from said cool air inlet port in said plenum to cool said electric motor.
Claim 9
Dependent Claim 50 words
A motor plenum as set forth in claim 1 which further includes a baffle inside said plenum adjacent said cool air inlet port for directing the cool air from said inlet port over the windings of the electric motor before being directed to said diversionary air vent during convection cooling.
Claim 10
Dependent Claim 26 words
A motor plenum as set forth in claim 2 which further includes temperature sensitive switch means for energizing said electric motor and said electric solenoid means.
Claim 11
Dependent Claim 55 words
A motor plenum as set forth in claim 1 wherein said means for closing said movable closure comprises a baffle plate slidably mounted on the side of said plenum and adapted to be moved to cover said diversionary air vent when said electric motor is normally not energized to circulate cool air through said plenum.
Claim 12
Dependent Claim 37 words
A motor plenum as set forth in claim 10 wherein said slidable baffle plate is spring biased in engagement with the side of said plenum and provided with a lever for sliding said plate up and down.
Claim 13
Independent Claim 162 words
A method of maintaining an electric motor in a fireplace plenum enclosure at a relatively low operational temperature, comprising: enclosing said electric motor in a metal plenum box, providing a lower intake port in the side of said metal plenum, providing an upper diversionary vent port on the same side of said metal plenum, providing an outlet port on the side of said metal plenum, providing an electric blower connected to said electric motor and having a blower inlet inside of said metal plenum and a blower outlet connected to said outlet port, means for opening said diversionary vent when said electric motor is not running, and closing said diversionary vent when said electric motor is running, and normally exhausting cool intake air from said lower intake port out through said diversionary vent when said electric motor is not running by convection heating the cool intake air with the heat of said metal plenum thereby providing convection cooling for said electric motor.
Claim 14
Independent Claim 162 words
A method of maintaining an electric motor in a fireplace plenum enclosure at a relatively low operational temperature, comprising: enclosing said electric motor in a metal plenum box, providing a lower intake port in the side of said metal plenum, providing an upper diversionary vent port on the same side of said metal plenum, providing an outlet port on the side of said metal plenum, providing an electric blower connected to said electric motor and having a blower inlet inside of said metal plenum and a blower outlet connected to said outlet port, means for opening said diversionary vent when said electric motor is not running, and closing said diversionary vent when said electric motor is running, and normally exhausting cool intake air from said lower intake port out through said diversionary vent when said electric motor is not running by convection heating the cool intake air with the heat of said metal plenum thereby providing convection cooling for said electric motor.

References Cited (Backward Citations)

US4010729A Cited
US4305473A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1986-10-10 1987-04-11 1987-10-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1990-10-10 1991-04-11 1991-10-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1994-10-10 1995-04-11 1995-10-11 $7700.00 Window Closed / Lapsed

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