Stable high temperature heater with serpentine heating strands on insulative substrate
AssigneeHeetronix
InventorJames D. Parsons
Life of this patent
Estimating the term…
Abstract
A sensor system has an AlN substrate, a W layer on the substrate, a signal source adapted to apply an electrical actuating signal to the W layer, and a sensor adapted to sense the response of the W layer. The W layer can comprise a thin film, with various types of optional protective layers over the film. Applications include sensing temperature, fluid flow rates, fluid levels, pressure and chemical environments. For a planar heater, the W layer comprises a plurality of conductive strands distributed on the substrate, with the strands generally parallel and serpentine shaped for a rectangular substrate, and extending along respective lines of longitude that merge at opposite poles of the substrate for a circular substrate.
Claims22
A heater comprising:
- an aluminum nitride (AlN) substrate, and
- a plurality of generally parallel and serpentine shaped tungsten conductive strands, said strands deposited as a thin film on said substrate, the shape and spacing of said strands and the thickness of said substrate arranged such that said heater can provide and tolerate a rapid heating rate without damaging said substrate.
A heater comprising:
- an insulative substrate,
- a plurality of generally parallel and serpentine shaped tungsten (W) conductive strands on said substrate,
- a signal source adapted to apply an electrical actuating signal to heat said strands,
- a sensor adapted to sense the response of said strands to said actuating signal as an indication of the temperature of said strands, said strands having a response to said actuating signal which varies with their temperature,
- an additional insulative substrate with a W layer thereon, said signal source connected to apply a substantially non-heating electrical signal to said W layer, and a sensor connected to sense a response of said W layer as an indication of its temperature,
- said additional substrate and said W layer disposed downstream of said substrate and strands in a fluid flow path, with the difference in temperature between said W layer and said strands corresponding to the fluid flow rate.
A heater comprising:
- an aluminum nitride (AlN) substrate, and
- a plurality of generally parallel and serpentine shaped tungsten conductive strands, said strands deposited as a thin film on said substrate, each of said strands providing a conduction path, said serpentine shape comprising a repeating pattern of a curved peak followed by a curved valley, wherein the peak-to-valley distance of the strands perpendicular to the centerline of said strand conduction path is more than the strand width, and the distance between the strand peaks and valleys parallel to the strand conduction path is not more than 2.5 cm,
- the shape and spacing of said strands and the thickness of said substrate arranged such that said heater can provide a heating rate of >100° C./second without damaging said substrate.
A heater comprising:
- an aluminum nitride (AlN) substrate having a thickness of ≦0.036 cm, and
- a plurality of generally parallel and serpentine shaped tungsten conductive strands, said strands deposited as a thin film on said substrate such that the width of each strand is not more than 0.25 cm and the spacing between said strands is not more than 0.18 cm,
- each of said strands providing a conduction path, said serpentine shape comprising a repeating pattern of a curved peak followed by a curved valley, wherein the peak-to-valley distance of the strands perpendicular to the centerline of said strand conduction path is more than the strand width, and the distance between the strand peaks and valleys parallel to the strand conduction path is not more than 2.5 cm,
- the shape and spacing of said strands and the thickness of said substrate arranged such that said heater can provide a heating rate of >100° C./second without damaging said substrate.
Dependencies are inferred from the claim text.