Thermostat for stoves

Claim 2

A thermostat for a stove, comprising: a housing having a thermostat aperture formed in a surface thereof; flap means movably secured to said housing and being movable in a manner which adjusts the effective size of said thermostat aperture between a fully open and a fully closed position; and thermal control unit means contained in said housing for detecting changes in the temperature of a stove to which said thermostat is attached and for moving said flap means as a function of said change in temperature; said flap means, said thermostat aperture and said thermal control unit means cooperating to cause the flow rate of air through said thermostat for a constant pressure differential across said thermostat to change by an amount approximately proportional to the square of said change in the temperature of said stove over a range of thermostat openings extending from at least said fully closed position to at least a partially open position, said flow rate being increased responsive to a fall in the stove temperature and being decreased responsive to a rise in the stove temperature.

Claim 3

The thermostat of claim 1, wherein said thermal control unit means has a substantially linear response to changes in the stove temperature.

Claim 4

The thermostat of claim 2, wherein said thermal control unit means comprises a bimetallic coil.

Claim 5

The thermostat of claim 3, wherein said bimetallic coil has an outer end secured to said flap means for moving said flap means responsive to a change in the stove temperature.

Claim 6

The thermostat of claim 4, wherein said housing includes an open end adapted to be coupled to a stove, said open end lying in a plane, said bimetallic coil being accommodated in said housing and located within approximately 1/4 inch of said plane.

Claim 7

The thermostat of claim 3, wherein said thermal control unit further comprises a control rod, said bimetallic coil having an outer end connected by means of said control rod to said flap means for moving said flap means responsive to the change in the temperature of the stove.

Claim 8

The thermostat of claim 3, further comprising a control knob, said bimetallic coil having an inner end connected to said control knob, said control knob adjusting the orientation of said bimetallic coil to determine the value of said flow rate at a given temperature.

Claim 9

The thermostat of claim 2, wherein said flap means is slidable with respect to said aperture and wherein said flap means and said thermostat aperture have respective predetermined shapes such that when said thermal control unit means moves said flap means a given amount, the respective said shapes of said flap means and of said thermostat aperture cooperate to change the effective area of said aperture by an amount approximately proportional to the square of the magnitude of said change in the stove temperature.

Claim 10

The thermostat of claim 8, wherein said flap means has a straight leading edge and said thermostat aperture has a curved edge.

Claim 11

The thermostat of claim 8, wherein said flap means has a curved leading edge and said thermostat aperture has a straight edge facing said leading edge.

Claim 12

The thermostat of claim 8, wherein said flap means has a curved leading edge and said thermostat aperture has a curved edge.

Claim 13

The thermostat of claim 1, wherein said thermal control unit means comprises a liquid expansion thermometer.

Claim 14

The thermostat of claim 1, wherein said housing is generally rectangular in form.

Claim 15

The thermostat of claims 1, 4 or 5 wherein said housing is cylindrical.

Claim 16

The thermostat of claim 14, wherein said cylindrical housing includes a cylindrical lateral surface, said thermostat aperture being formed in said cylindrical lateral surface.

Claim 17

The thermostat of claim 14, wherein said thermostat aperture defines a first thermostat aperture and said flap means defines a first flap means and wherein said thermostat further includes a second thermostat aperture, both of said thermostat apertures being formed in said cylindrical lateral surface.

Claim 18

The thermostat of claim 16, wherein said thermostat further includes a second flap means, said second flap means being secured to said housing and movable in a manner which adjusts the flow rate of air through said second thermostat aperture, said first and second flap means being slidable with respect to said first and second apertures, respectively, and being secured to each other in such a manner that the flow rate of air through said first and second thermostat apertures are at all times the same.

Claim 19

The thermostat of claim 17, wherein said first and second thermostat apertures have the same shape.

Claim 20

The thermostat of claim 1, further comprising a flange integral with said housing for securing said thermostat to a stove.

Claim 21

The thermostat of claim 19, further comprising a baffle secured to said housing for protecting said thermal control unit means from drafts of air.

Claim 22

The thermostat of claim 1, wherein said housing has an open end adapted to be coupled to said stove and wherein said thermostat further comprises baffle means secured to said housing in such a manner that air entering said thermostat via said thermostat aperture must move around said baffle means in order to reach said open end of said housing.

Claim 23

The thermostat of claim 1, further including shut off means for causing said flap means to close said aperture and thereby cut off air flow through said aperture whenever the temperature in said housing rises above a predetermined level.

Claim 24

The thermostat of claim 4, further including shut off means for causing said flap means to close said aperture and thereby cut off air flow through said aperture whenever the temperature in said housing rises above a predetermined level.

Claim 25

The thermostat of claim 23, wherein said shut off means includes a fusible link coupling said bimetallic coil to said housing and adapted to melt when said temperature in said housing rises above said predetermined level.

Claim 26

A stove having a thermostat control, comprising: a stove, said stove having a wall and said wall having an air inlet aperture formed therein; a housing having a thermostat aperture formed in a surface thereof; means for securing said housing to said stove at a location on said stove such that air which enters said housing via said thermostat aperture will enter the stove via said air inlet aperture; flap means movable with respect to said thermostat aperture in a manner which adjusts the effective size of said thermostat aperture between a fully closed and a fully opened position; and thermal control unit means contained in said housing for detecting changes in the temperature of said stove and for moving said flap means as a function of said change in temperature of said stove; said flap means, said thermostat aperture and said thermal control unit means cooperating to cause flow rate of air through said thermostat, for a constant pressure differential across the thermostat, to change by an amount approximately proportional to the square of said change in said stove temperature over a range of thermostat openings extending from at least said fully closed position to at least a partially open position, said flow rate being increased responsive to a fall in the stove temperature and being decreased responsive to a rise in the stove temperature.

Claim 27

A stove having a thermostat control, comprising: a stove, said stove having a wall and said wall having an air inlet aperture formed therein; a housing having a thermostat aperture formed in a surface thereof; means for securing said housing to said stove at a location on said stove such that air which enters said housing via said thermostat aperture will enter the stove via said air inlet aperture; flap means movable with respect to said thermostat aperture in a manner which adjusts the effective size of said thermostat aperture between a fully closed and a fully opened position; and thermal control unit means contained in said housing for detecting changes in the temperature of said stove and for moving said flap means as a function of said change in temperature of said stove; said flap means, said thermostat aperture and said thermal control unit means cooperating to cause flow rate of air through said thermostat, for a constant pressure differential across the thermostat, to change by an amount approximately proportional to the square of said change in said stove temperature over a range of thermostat openings extending from at least said fully closed position to at least a partially open position, said flow rate being increased responsive to a fall in the stove temperature and being decreased responsive to a rise in the stove temperature.

Claim 28

The stove of claim 25, further comprising means for placing said thermal control unit into direct thermal contact with the interior of said stove.

Claim 29

The stove of claim 26, wherein said direct thermal contact means comprises a thermally conductive rod in contact with said thermal control unit means and penetrating said wall of said stove, and a thermally conductive plate secured to said rod in the interior of said stove.

Claim 30

The stove of claim 27, wherein said plate and said rod are brass.

Claim 31

The stove of claim 27, wherein said plate and said rod are aluminum.

Claim 32

The stove of claim 25, 26 or 27, wherein said wall of said stove has a thickness no greater than approximately 1/16 inch.

Claim 33

The stove of claim 25, further including shut off means for causing said flap means to close said aperture and thereby cut off air flow to said stove whenever the temperature in said stove rises above a predetermined level.

Claim 34

The stove of claim 31, wherein said thermal control unit means includes a bimetallic coil which controls the position of said flap means and wherein said shut off means includes a fusible link coupling said bimetallic coil to said housing and adapted to melt when said temperature in said stove rises above said predetermined value.