Shorted turn axial driver-sensor

Claim 2

In a pressure measuring system that includes a diaphragm subjected to differential gas pressure on its opposite faces, means mounting the diaphragm for resonant vibration along a predetermined axis at a frequency determined by the differential gas pressure, and means responsive in accordance with the frequency of vibration of the diaphragm for producing an output signal representative of the differential gas pressure acting on the diaphragm, the combination of an electromagnetic element mounted to a center portion of said diaphragm to vibrate along said axis in unison therewitH, said electromagnetic element having a shorted turn encircling said axis, a magnetic yoke assembly providing a magnetic flux loop that includes a gap encircling said axis to receive said shorted turn and define a radial flux field symmetrically intercepting the shorted turn to synchronize axial movement of the shorted turn with magnetic flux changes in said gap, and electric circuit means including a coil electromagnetically coupled to said yoke assembly for actuating said element to establish resonant vibration thereof.

Claim 3

In a system as defined in claim 1 wherein said magnetic yoke assembly includes a cylindrical core structure projecting along said axis and having a main section of permanent magnet material and a cylindrical end section of soft iron material and a cylindrical pole face concentrically encircling the end section to define an annular gap configuration.

Claim 4

In a system as defined in claim 2 wherein said magnetic yoke assembly includes a base disc of magnetic material supporting said core structure centrally thereof and a cup-shaped structure having a cylindrical side wall endwise abutting said base disc to surround said core structure and having an end wall provided with a central hole to define said cylindrical pole face.

Claim 5

In a system as defined in claim 1 wherein said magnetic yoke assembly includes a cylindrical core structure of soft iron material projecting along said axis to form substantially the entire central leg of the magnetic flux loop, a cylindrical pole face concentrically encircling the core structure to define an annular gap and a ring-shaped permanent magnet interposed in said yoke assembly in concentric outwardly spaced relation to said axis to act in series in said magnetic flux loop.

Claim 6

In a system as defined in claim 4 wherein said electromagnetic element comprises a sleeve of electrically conductive, non-magnetic material and extending concentrically of said axis.

Claim 7

In a pressure measuring system that includes an aneroid pressure capsule having a set of opposed diaphragm walls for resonant vibration in opposing synchronism along a common axis at a frequency determined by differential gas pressure acting on each diaphragm wall, the combination of a separate electromagnetic element mounted to a center portion of each diaphragm wall to vibrate in unison therewith, each electromagnetic element having a shorted turn encircling said axis, a separate magnetic yoke assembly cooperating with each electromagnetic element, each yoke assembly providing a magnetic flux loop that includes a gap encircling said axis to receive the corresponding shorted turn and define a radial flux field symmetrically intercepting such shorted turn to synchronize axial movement of each shorted turn with magnetic flux changes in the corresponding gap, and oscillator circuit means including a separate coil electromagnetically coupled to each yoke assembly, and means connecting said coils in positive feedback relation to establish oscillation of the oscillator circuit means at a resonant frequency determined by the pressure conditions acting on the capsule diaphragms.

Claim 8

In a pressure measuring system that includes an aneroid pressure capsule having a set of opposed diaphragm walls for resonant vibration in opposing synchronism along a common axis at a frequency determined by differential gas pressure acting on each diaphragm wall, the combination of a separate electromagnetic element mounted to a center portion of each diaphragm wall to vibrate in unison therewith, each electromagnetic element having a shorted turn encircling said axis, a separate magnetic yoke assembly cooperating with each electromagnetic element, each yoke assembly providing a magnetic flux loop that includes a gap encircling said axis to receive the corresponding shorted turn and define a radial flux field symmetrically intercepting such shorted turn to synchronize axial movement of each shorted turn with magnetic flux changes in the corresponding gap, and oscillator circuit means including a separate coil electromagnetically coupled to each yoke assembly, and means connecting said coils in positive feedback relation to establish oscillation of the oscillator circuit means at a resonant frequency determined by the pressure conditions acting on the capsule diaphragms.

Claim 9

In a system as defined in claim 6 wherein each electromagnetic element comprises a sleeve of electrically conductive, non-magnetic material extending concentrically of said axis and having one end anchored to said central wall portion.

Claim 10

In a pressure measuring system that includes a pressure capsule having a set of opposed diaphragm walls for resonant vibration in opposing synchronism along a common axis at a frequency determined by differential gas pressure acting on each diaphragm wall, the combination of a separate electromagnetic element mounted to a center portion of each diaphragm wall to vibrate in unison therewith, each magnetic element having an end portion concentric with said common axis, a support ring structure encircling said capsule to hold the capsule in predetermined alignment, said support ring structure having oppositely directed annular shoulders encircling the commOn axis, and a separate magnetic yoke assembly cooperating with each electromagnetic element, each yoke assembly providing a magnetic flux loop that includes a magnetic gap encircling said axis to receive the end portion of the corresponding electromagnetic element to define a radial flux field symmetrically, intercepting the same to synchronize axial movement thereof with magnetic flux changes in the corresponding gap, said yoke assemblies having oppositely directed annular shoulders mating with the annular shoulders of the support ring structure to locate each magnetic gap in accurate registry with the end portion of the corresponding electromagnetic element and oscillator circuit means including a separate coil electromagnetically coupled to each yoke assembly, and means connecting said coils in positive feedback relation to establish oscillation of the oscillator circuit means at a resonant frequency determined by the pressure conditions acting on the capsule diaphragms.

Claim 11

In a pressure measuring system that includes a pressure capsule having a set of opposed diaphragm walls for resonant vibration in opposing synchronism along a common axis at a frequency determined by differential gas pressure acting on each diaphragm wall, the combination of a separate electromagnetic element mounted to a center portion of each diaphragm wall to vibrate in unison therewith, each magnetic element having an end portion concentric with said common axis, a support ring structure encircling said capsule to hold the capsule in predetermined alignment, said support ring structure having oppositely directed annular shoulders encircling the commOn axis, and a separate magnetic yoke assembly cooperating with each electromagnetic element, each yoke assembly providing a magnetic flux loop that includes a magnetic gap encircling said axis to receive the end portion of the corresponding electromagnetic element to define a radial flux field symmetrically, intercepting the same to synchronize axial movement thereof with magnetic flux changes in the corresponding gap, said yoke assemblies having oppositely directed annular shoulders mating with the annular shoulders of the support ring structure to locate each magnetic gap in accurate registry with the end portion of the corresponding electromagnetic element and oscillator circuit means including a separate coil electromagnetically coupled to each yoke assembly, and means connecting said coils in positive feedback relation to establish oscillation of the oscillator circuit means at a resonant frequency determined by the pressure conditions acting on the capsule diaphragms.

Claim 12

In a pressure measuring system as defined in claim 8 wherein each electromagnetic element comprises a sleeve of electrically conductive, non-magnetic material extending concentrically of said axis and having one end anchored to said central wall portion.

Claim 13

In a pressure measuring system as defined in claim 9 wherein each magnetic yoke assembly includes a cylindrical core structure projecting along said axis and having a main section of permanent magnet material and a cylindrical end section of soft iron material and a cylindrical pole face concentrically encircling the end section to define an annular gap configuration.

Claim 14

In a system as defined in claim 8 wherein said magnetic yoke assembly includes a cylindrical core structure of soft iron material projecting along said axis to form substantially the entire central leg of the magnetic flux loop, a cylindrical pole face concentrically encircling the core structure to define an annular gap and a ring-shaped permanent magnet interposed in said yoke assembly in concentric outwardly spaced relation to said axis to act in series in said magnetic flux loop.

Claim 15

In a system as defined in claim 11 wherein said electromagnetic element comprises a sleeve of electrically conductive, non-magnetic material and extending concentrically of said axis.