US4604895A — Hot wire anemometer

Claim 1

Independent Claim 211 words

An electronic anemometer for measuring air mass flow in a conduit, comprising: a straight length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the electronic circuitry used when the anemometer is operating to maintain said wire at a substantially constant temperature and generate an air mass flow-indicating signal based upon the air mass flow in the conduit sampled by said wire; a rigid support plate having a pair of spaced-apart openings, said plate being fixedly attached to said circuit board; a pair of electrically nonconductive support inserts, each of said inserts being fixedly retained within one of said openings in said support plate; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positionable in a central portion of the conduit with said wire substantially transverse to the airflow, said end portions being biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by one of said support inserts, said remote end portion being electrically connected to the electronic circuitry.

Claim 2

Dependent Claim 211 words

An electronic anemometer for measuring air mass flow in a conduit, comprising: a straight length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the electronic circuitry used when the anemometer is operating to maintain said wire at a substantially constant temperature and generate an air mass flow-indicating signal based upon the air mass flow in the conduit sampled by said wire; a rigid support plate having a pair of spaced-apart openings, said plate being fixedly attached to said circuit board; a pair of electrically nonconductive support inserts, each of said inserts being fixedly retained within one of said openings in said support plate; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positionable in a central portion of the conduit with said wire substantially transverse to the airflow, said end portions being biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by one of said support inserts, said remote end portion being electrically connected to the electronic circuitry.

Claim 3

Dependent Claim 26 words

The anemometer of claim 1 wherein said circuit board is attachable to the conduit at a plurality of longitudinally spaced and aligned points along the conduit.

Claim 4

Dependent Claim 13 words

The anemometer of claim 1 wherein said resistive wire is composed of platinum.

Claim 5

Dependent Claim 17 words

The anemometer of claim 3 wherein said platinum wire has a tensile strength of about 0.4 pound.

Claim 6

Dependent Claim 15 words

The anemometer of claim 1 wherein said posts are composed of phosphorous bronze spring wire.

Claim 7

Dependent Claim 37 words

The anemometer of claim 1 wherein said posts have sufficient length to position said resistive wire in the central portion of the conduit at least 331/3% of the conduit diameter from the interior walls of the conduit.

Claim 8

Dependent Claim 24 words

The anemometer of claim 6 wherein said resistive wire extending between said wire-supporting end portions is of a length extending within said central portion.

Claim 9

Dependent Claim 129 words

An electronic anemometer for measuring air mass flow in a conduit, comprising: a length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the anemometer electronic circuitry; a rigid support member, said circuit board being attached to said member; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positionable in the conduit, and biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by said support member, said remote end portions being electrically connected to the electronic circuitry.

Claim 10

Dependent Claim 129 words

An electronic anemometer for measuring air mass flow in a conduit, comprising: a length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the anemometer electronic circuitry; a rigid support member, said circuit board being attached to said member; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positionable in the conduit, and biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by said support member, said remote end portions being electrically connected to the electronic circuitry.

Claim 11

Dependent Claim 31 words

The anemometer of claim 8 wherein said support member includes electrically nonconductive post support means for fixedly holding said remote end portions and preventing their electrical contact with said support member.

Claim 12

Dependent Claim 213 words

An electronic anemometer for measuring air mass flow, comprising: a conduit; a straight length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the electronic circuitry used when the anemometer is operating to maintain said wire at a substantially constant temperature and generate an air mass flow-indicating signal based upon the air mass flow in said conduit sampled by said wire; a rigid support plate having a pair of spaced-apart openings, said plate being fixedly attached to said circuit board; a pair of electrically nonconductive support inserts, each of said inserts being fixedly retained within one of said openings in said support plate; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positioned in a central portion of said conduit with said wire substantially transverse to the direction of airflow therein, said end portions being biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by one of said support inserts, said remote end portions being electrically connected to the electronic circuitry.

Claim 13

Dependent Claim 213 words

An electronic anemometer for measuring air mass flow, comprising: a conduit; a straight length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the electronic circuitry used when the anemometer is operating to maintain said wire at a substantially constant temperature and generate an air mass flow-indicating signal based upon the air mass flow in said conduit sampled by said wire; a rigid support plate having a pair of spaced-apart openings, said plate being fixedly attached to said circuit board; a pair of electrically nonconductive support inserts, each of said inserts being fixedly retained within one of said openings in said support plate; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of said posts having a wire-supporting end portion fixedly connected to said wire, said end portions being spaced apart and positioned in a central portion of said conduit with said wire substantially transverse to the direction of airflow therein, said end portions being biased away from each other to hold said wire under tension, each of said posts further having a remote end portion fixedly held by one of said support inserts, said remote end portions being electrically connected to the electronic circuitry.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-08-11	1990-02-10	1990-08-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-08-11	1994-02-10	1994-08-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-08-11	1998-02-10	1998-08-12	$7700.00	Window Closed / Lapsed

Hot wire anemometer

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