US5067351A — Magnetohydrodynamic angular rate sensor for measu…

Claim 1

Independent Claim 168 words

An electronic angular rate sensor comprising: a metallic case open at one end having a high magnetic flux density including a central cavity; a magnet located at the bottom of said case, having a north/south axis oriented in the direction of said cavity axis; an insulating member covering said magnet and sealing said magnet from the remaining portion of said cavity; a conductive center post having one end supported on said insulating member, extending along the axis of said cavity; a channel cap disposed in said cavity and spaced apart from said insulating member, forming a sealed channel with said insulating member and said metallic case, said channel containing mercury, said channel cap having a central opening through which said center post extends; and, an amplifying circuit mounted on a header which closes said cavity, having first and second input connections connected respectively to said metallic case and said center post, providing a voltage proportional to the angular rate of said metallic case about said central cavity axis.

Claim 2

Dependent Claim 168 words

An electronic angular rate sensor comprising: a metallic case open at one end having a high magnetic flux density including a central cavity; a magnet located at the bottom of said case, having a north/south axis oriented in the direction of said cavity axis; an insulating member covering said magnet and sealing said magnet from the remaining portion of said cavity; a conductive center post having one end supported on said insulating member, extending along the axis of said cavity; a channel cap disposed in said cavity and spaced apart from said insulating member, forming a sealed channel with said insulating member and said metallic case, said channel containing mercury, said channel cap having a central opening through which said center post extends; and, an amplifying circuit mounted on a header which closes said cavity, having first and second input connections connected respectively to said metallic case and said center post, providing a voltage proportional to the angular rate of said metallic case about said central cavity axis.

Claim 3

Dependent Claim 26 words

The angular rate sensor of claim 1 further comprising a threaded mounting means integral with said case having a common axis with said central cavity axis.

Claim 4

Dependent Claim 15 words

The angular rate sensor of claim 1 wherein said case is a vanadium permendur alloy.

Claim 5

Dependent Claim 82 words

The angular rate sensor of claim 1 wherein said output voltage (frequency response) is proportional to ##EQU5## where ##EQU6## is the amplifying circuit frequency response function, and, Bo is the mercury channel magnetic flux density, r is the mercury channel root mean square radius, w is the mercury channel effective width, ##EQU7## (τ is the transducer-time constant in seconds), where ν is the kinematic viscosity of mercury, h is the mercury channel effective height, and M is the Hartmann number for mercury.

Claim 6

Dependent Claim 151 words

An electronic angular rate sensor comprising: a cylindrical metallic case open at one end having a high magnetic flux density including a central cavity therein; a permanent magnet at the bottom of said cavity having a north/south axis oriented in the direction of said central cavity axis; a conductive liquid channel disposed in said cavity above said permanent magnet and insulated from said magnet, said conductive liquid channel bounded on sides thereof by said cavity, forming an electrical contact therewith, and at the top thereof by a lid; a center post extending through said lid into said conductive liquid channel, forming an electrode for said angular rate sensor; and, an amplifier circuit supported on a header closing said cavity, said amplifier circuit having input connections connected to said center post and said case, said header sealing said central cavity, and supporting on an exterior thereof electrical connections for said amplifier circuit.

Claim 7

Dependent Claim 151 words

An electronic angular rate sensor comprising: a cylindrical metallic case open at one end having a high magnetic flux density including a central cavity therein; a permanent magnet at the bottom of said cavity having a north/south axis oriented in the direction of said central cavity axis; a conductive liquid channel disposed in said cavity above said permanent magnet and insulated from said magnet, said conductive liquid channel bounded on sides thereof by said cavity, forming an electrical contact therewith, and at the top thereof by a lid; a center post extending through said lid into said conductive liquid channel, forming an electrode for said angular rate sensor; and, an amplifier circuit supported on a header closing said cavity, said amplifier circuit having input connections connected to said center post and said case, said header sealing said central cavity, and supporting on an exterior thereof electrical connections for said amplifier circuit.

Claim 8

Dependent Claim 21 words

The angular rate sensor of claim 5 wherein a center pin extends through said header, and also contacts said center post.

Claim 9

Dependent Claim 32 words

The angular rate sensor of claim 5 wherein said permanent magnetic is insulated from said channel with an epoxy cover, and has a north pole at the bottom of said central cavity.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-11-25	1995-05-27	1995-11-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-11-25	1999-05-27	1999-11-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-11-25	2003-05-27	2003-11-26	$7700.00	Window Closed / Lapsed

Magnetohydrodynamic angular rate sensor for measuring large angular rates

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