ELECTRICALLY HEATED WINDOW WITH A TEMPERATURE SENSOR
First Claim
2. The window of claim 1 in which the transparent window comprises a plurality of transparent rigid sheets.
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Abstract
An electrically heated transparent window and a constant temperature control system for such transparency is disclosed. In the preferred embodiment the transparency includes a plastic interlayer material sandwiched between two rigid, transparent sheets, one of which sheets has an electrical heating means adjacent to it and in contact with the interlayer. Embedded within the plastic interlayer is a temperature sensor which is comprised of a resistance filament encapsulated within a casing material which has a heat deflection temperature greater than the plastic interlayer. Because the temperature sensor has a casing with a higher heat deflection temperature than the plastic interlayer into which it is embedded, fracture and shorting of the resistance filament against the electrical heating means, during the high temperature and high pressure conditions of laminating, are avoided. In a particular embodiment of the invention where the interlayer material is plasticized, a protective layer disposed between the interlayer and casing material to prevent hazing is disclosed.
43 Citations
27 Claims
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2. The window of claim 1 in which the transparent window comprises a plurality of transparent rigid sheets.
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3. The window of claim 2 in which the transparent window comprises a plurality of transparent rigid sheets laminated together with said plastic sheets as an interlayer, the temperature sensing element being embedded in said interlayer.
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4. The window of claim 3 in which the electrical heating element comprises fine resistance wires embedded in said interlayer.
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5. The window of claim 3 in which the electrical heating element is an electrical conductive coating on at least one of said rigid sheets.
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6. The window of claim 3 in which the plastic interlayer is polyvinyl butyral.
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7. The window of claim 6 in which the polyvinyl butyral is plasticized.
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8. The window of claim 6 in which the casing material is an organic composition taken from the classs consisting of poly-carbonate and acrylic.
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9. The window of claim 7 in which the casing material is polycarbonate and a protective coating is disposed between the casing and the interlayer.
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10. The window of claim 9 in which the protective coating is acrylic.
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11. The window of claim 10 in which an adhesive is inserted between the interlayer and the protective coating.
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12. The window of claim 11 in which the adhesive is polyurethane.
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13. The window of claim 8 in which the casing material is acrylic and a polyurethane adhesive is inserted between the interlayer and the casing.
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14. A transparent, laminated window which is capable of being electrically heated, comprising in combination:
- a. a plurality of transparent, rigid sheets, at least one of which has an electrical heating means on an inwardly facing surface thereof for heating said window, b. a plastic interlayer disposed between two of said rigid sheets and contacting said electrical heating means, c. a temperature sensing element having an electrical resistivity sensitive to a change in temperature embedded in said interlayer in spaced relation to said electrical heating means, which element comprises a resistance filament hermetically encapsulated within a transparent casing material which has a higher heat deflection temperature than the interlayer material, and d. electrical leads electrically coupled to said temperature sensing element and extending through said casing and said interlayer and adapted for connection to a control system.
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15. The constant temperature window system of claim 14 in which the transparent window comprises two rigid sheets.
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16. The constant temperature window system of claim 14 in which the electrical heating means comprises an electrically conductive coating on at least one of said rigid sheets.
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17. The constant temperature window system of claim 14 in which the plastic interlayer is polyvinyl butyral.
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18. The constant temperature window system of claim 17 in which the polyvinyl butyral is plasticized.
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19. The constant temperature window system of claim 17 in which the casing material is composed of a plastic composition taken from the class consisting of polycarbonate and acrylic.
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20. The constant temperature window system of claim 18 in which the casing material is polycarbonate and a protective coating is disposed between the casing and the interlayer.
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21. The constant temperature window system of claim 20 in which the protective coating is acrylic.
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22. The constant temperature window system of claim 21 in which an adhesive is inserted between the acrylic and the interlayer.
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23. The constant temperature window system of claim 22 in which the adhesive is polyurethane.
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24. The constant temperature window system of claim 19 in which the casing material is acrylic and a polyurethane adhesive is inserted between the casing and the interlayer.
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25. A constant temperature windOw system comprising in combination:
- a. an electrically heated transparent window which includes;
i. a transparent rigid sheet and a transparent plastic sheet;
ii. an electrical heating element for heating said window embedded within said window and supported by said transparent plastic sheet and being operatively connected to a source of electrical energy;
iii. a temperature sensing element having an electrical resistivity sensitive to a change in temperature embedded in said transparent plastic sheet in spaced relation to said electrical heating element;
the temperature sensing element comprising a resistance filament hermetically encapsulated within a transparent casing material which has a higher heat deflection temperature than the transparent plastic sheet, iv. electrical leads for operatively connecting said electrical heating element and said temperature sensor to the same source of electrical energy;
whereby the temperature sensing element responds to changes in temperature appurtenant said window and modifies the source of electrical energy so as to maintain the temperature of the window at predetermined range.
- a. an electrically heated transparent window which includes;
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26. The constant temperature window system of claim 25 in which the electrical heating means comprises fine resistance wires embedded in said interlayer.
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27. A constant temperature window system comprising in combination:
- a. a transparent, laminated, electrically conducting window which includes;
i. a plurality of rigid, transparent sheets and a plastic interlayer which has an electrical heating means embedded therein and which electrical heating means is operatively connected to a source of electrical energy;
ii. said plastic interlayer being disposed between two of said sheets and contacting the electrical heating means;
b. a temperature sensing element having an electrical resistivity sensitive to a change in temperature embedded in said interlayer in spaced relation to said electrical heating means, the temperature sensing element including;
i. a resistance filament hermetically encapsulated within a casing material which has a higher heat deflection temperature than said interlayer material, ii. electroconductive means operatively connecting said electrical heating means and said temperature sensing element to the same source of electrical energy;
whereby the temperature sensing element responds to changes in temperature appurtenant said window and modifies the source of electrical energy so as to maintain the temperature of the window at a predetermined range.
- a. a transparent, laminated, electrically conducting window which includes;
Specification