Mass flow sensor
AssigneeFord Motor Company
InventorsChester J. Blechinger, Paul E. Stevenson
Life of this patent
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Abstract
A flow sensor which includes a support structure including a base having a plurality of spaced mesas on a surface thereof is provided. A low thermal conductivity, dielectric diaphragm spanning the mesas is supported along its length thereby and forms an electrical and thermal insulation barrier over the support structure and the mesas. At least one flow sensing element is superposed on the diaphragm so that the flow sensing element is substantially electrically and thermally isolated from the support structure. A method for fabricating the flow sensor is also provided.
Claims17
A flow sensor comprising:
- (a) a support structure including a base having a plurality of spaced mesas on a surface thereof;
- (b) a low thermal conductivity, dielectric diaphragm spanning said mesas;
- said diaphragm having first and second ends wherein said mesas are positioned at said first and second ends and at least one of said mesas is positioned intermediate said first and second ends to support said diaphragm so as to prevent breakage along its length;
- said diaphragm forming an electrical and thermal insulation barrier over said support structure and said mesas;
- and
- (c) at least one flow sensing element superposed on said diaphragm so that said at least one flow sensing element is substantially electrically and thermally isolated from said support structure.
A flow sensor comprising:
- (a) a <100>
- silicon wafer including a base having a plurality of spaced mesas having a height of about 5.0 microns to about 100 microns on one surface thereof;
- (b) a low thermal conductivity, dielectric diaphragm made from materials selected from the group consisting of silicon nitride, silicon oxide and combinations thereof;
- said diaphragm spanning said mesas;
- said diaphragm having first and second ends wherein said mesas are positioned at said first and second ends and at least one of said mesas is positioned intermediate said first and second ends to support said diaphragm so as to prevent breakage along its length;
- said diaphragm forming an electrical and thermal insulation barrier over said support structure and said mesas;
- (c) a first metal coating superposed on said diaphragm adapted to be used as an air temperature sensor;
- and
- (d) a second metal coating superposed on said diaphragm adapted to be used as a hot wire anemometer.
A flow sensor comprising:
- (a) a support structure including a base having a plurality of spaced mesas on a surface thereof;
- (b) a low thermal conductivity, dielectric diaphragm spanning said mesas;
- said diaphragm having a length and a width wherein said mesas are spaced at a plurality of locations of not less than three along each of said length and said width to support said diaphragm so as to prevent breakage thereof;
- said diaphragm forming an electrical and thermal insulation barrier over said support structure and said mesas;
- and
- (c) at least one flow sensing element superposed on said diaphragm so that said at least one flow sensing element is substantially electrically and thermally isolated from said support structure.
Dependencies are inferred from the claim text.