Segmented PTC Heating Element Array

1 . A PTC heating appliance comprising:

a heating element array including a first plurality of PTC chips stacked into a second plurality of columns and including porous heat-exchanging radiators each in thermal communication with one or more of the columns and arranged such that heat produced by any of the PTC chips is conducted into the porous heat-exchanging radiator or radiators with which it is in thermal communication;

a fan arranged to force air through the porous heat exchanging radiators such that the heat therein is extracted and blown from the appliance; and

a control adapted to cause selective energization of sub-groups of the PTC chips and having at least a high and a low setting; wherein

a higher number of the PTC chips is energized during the high setting than during the low setting; and wherein

each subgroup includes energized PTC chips distributed evenly about the array.

2 . The PTC heating appliance of claim 1 in which the heat exchanging radiators are formed of thin aluminum finning arranged in a serpentine shape and soldered to aluminum sidewalls.

3 . The PTC heating appliance of claim 2 in which the PTC chips are placed against the sidewalls with a layer of thermal conduction paste between.

4 . The PTC heating appliance of claim 3 in which the controller is a switch having an off position during which the PTC chips and the fan are not energized and having a high position adapted to cause the high power setting and a low position adapted to cause the low power setting.

5 . The PTC heating appliance of claim 4 in which the switch further comprises a medium position adapted to cause a medium power setting during which less of the PTC chips are energized than during the high setting and more of the PTC chips are energized than during the low setting number; and wherein the energized PTC chips are distributed evenly about the array during the medium setting.

6 . The PTC heating appliance of claim 5 in which;

during the high power setting all PTC chips are energized so that all porous heat-exchanging radiators are heated evenly across the array;

during the medium setting the uppermost and lowermost PTC chips of the outermost columns and the innermost chips of the innermost columns are energized so that all porous heat-exchanging radiators are less heated evenly across the array; and

during the low setting the energized PTC chips are distributed evenly about the array so that the entire heating element array is even less heated evenly across the array.

7 . The PTC heating appliance of claim 1 in which the controller is a switch having an off position during which the PTC chips and the fan are not energized and having a high position adapted to cause the high power setting and a low position adapted to cause the low power setting.

8 . The PTC heating appliance of claim 7 in which the switch further comprises a medium position adapted to cause a medium power setting during which less of the PTC chips are energized than during the high setting and more of the PTC chips are energized than during the low setting; and wherein the energized PTC chips are distributed evenly about the array during the medium setting.

9 . The PTC heating appliance of claim 8 in which;

during the high power setting all PTC chips are energized so that all porous heat-exchanging radiators are heated evenly across the array;

during the medium setting the uppermost and lowermost PTC chips of the outermost columns and the innermost chips of the innermost columns are energized so that all porous heat-exchanging radiators are less heated evenly across the array; and

during the low setting the energized PTC chips are distributed evenly about the array so that the entire heating element array is even less heated evenly across the array.

10 B 1 . A PTC heating appliance comprising:

a heating element array including a first plurality of PTC chips stacked into a second plurality of columns and including porous heat-exchanging radiators each in thermal communication with one or more of the columns and arranged such that heat produced by any of the PTC chips is conducted into the porous heat-exchanging radiator or radiators with which it is in thermal communication;

a fan arranged to force air through the porous heat exchanging radiators such that the heat therein is extracted and blown from the appliance; and

a control adapted to cause selective energization of sub-groups of the PTC chips and having at least a high and a low setting; wherein

a higher number of the PTC chips is energized during the high setting than during the low setting; and wherein

each subgroup includes at least one PTC chip of each column.

11 . The PTC heating appliance of claim 10 in which the heat exchanging radiators are formed of thin aluminum finning arranged in a serpentine shape and soldered to aluminum sidewalls.

12 . The PTC heating appliance of claim 11 in which the PTC chips are placed against the sidewalls with a layer of thermal conduction paste between.

13 . The PTC heating appliance of claim 12 in which the controller is a switch having an off position during which the PTC chips and the fan are not energized and having a high position adapted to cause the high power setting and a low position adapted to cause the low power setting.

14 . The PTC heating appliance of claim 13 in which the switch further comprises a medium position adapted to cause a medium power setting during which less of the PTC chips are energized than during the high setting and more of the PTC chips are energized than during the low setting number; and wherein at least one PTC chip is energized in each column during the medium setting.

15 . The PTC heating appliance of claim 14 in which;

during the high power setting all PTC chips are energized so that all porous heat-exchanging radiators are heated evenly across the array;

during the medium setting the uppermost and lowermost PTC chips of the outermost columns and the innermost chips of the innermost columns are energized so that all porous heat-exchanging radiators are less heated evenly across the array; and

during the low setting one PTC chip in each column is energized so that the entire heating element array is even less heated evenly across the array.

16 . The PTC heating appliance of claim 10 in which the controller is a switch having an off position during which the PTC chips and the fan are not energized and having a high position adapted to cause the high power setting and a low position adapted to cause the low power setting.

17 . The PTC heating appliance of claim 16 in which the switch further comprises a medium position adapted to cause a medium power setting during which less of the PTC chips are energized than during the high setting and more of the PTC chips are energized than during the low setting; and wherein at least one PTC chip is energized in each column during the medium setting.

18 . The PTC heating appliance of claim 17 in which;

during the high power setting all PTC chips are energized so that all porous heat-exchanging radiators are heated evenly across the array;

during the medium setting the uppermost and lowermost PTC chips of the outermost columns and the innermost chips of the innermost columns are energized so that all porous heat-exchanging radiators are less heated evenly across the array; and

during the low setting one PTC chip in each column is energized so that the entire heating element array is even less heated evenly across the array.