Vibrating cylinder pressure transducer

Claim 2

A vibrating cylinder pressure transducer subcombination comprising: a base member; a vibrating cylinder composed of material having magnetic permeability, closed at one end and disposed in pressure sealing relationship against said base member at the other end thereof to form a first pressure chamber; an outer pressure cylinder composed of a substantially low magnetic permeability material, and at least partially closed at one end and disposed in pressure sealing relationship against said base member and surrounding said vibrating cylinder to form a second pressure chamber between said vibrating cylinder and said outer pressure cylinder; inlet means provided for one of said chambers so as to provide fluid communication between one of said chambers and a source of fluid, the pressure of which is to be measured by said transducer; electromagnetic drive means disposed on said outer pressure cylinder and in driving relationship with said vibrating cylinder; electromagnetic sensing means disposed on said outer pressure cylinder and in sensing relationship with said vibrating cylinder; and low reluctance magnetic path means disposed externally of said outer pressure cylinder for providing a return path for magnetic flux through said electromagnetic means and said vibrating cylinder.

Claim 3

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said drive means comprise a plurality of electromagnets spaced about the periphery of said outer cylinder.

Claim 4

A vibrating cylinder pressure transducer subcombination according to claim 2 wherein said drive means comprise an even number of electromagnetics, a first half of which provide an average magnetic flux to said vibrating cylinder of one polarity and the second half of which provide an average magnetic flux to said vibrating cylinder of a polarity opposite to that of said first half.

Claim 5

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said sense means comprise a plurality of electromagnets spaced about the periphery of said outer cylinder.

Claim 6

A vibrating cylinder pressurE transducer subcombination according to claim 4 wherein said drive means comprise an even number of electromagnetics, a first half of which provide an average magnetic flux to said vibrating cylinder of one polarity and the second half of which provide an average magnetic flux to said vibrating cylinder of a polarity opposite to that of said first half.

Claim 7

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said drive means comprises a group of electromagnets, said sensing means comprises a group of electromagnets, and the electromagnets in one group of said grorups of electromagnets are spaced from each other by an angle of less than 180*.

Claim 8

A vibrating cylinder pressure transducer subcombination according to claim 6 wherein the electromagnets of the other of said groups of electromagnets are disposed substantially symmetrically with respect to said first group of electromagnets, thereby cancelling magnetic fields induced in said electromagnetic sensing means by said electromagnetic drive means.

Claim 9

A vibrating cylinder pressure transducer subcombination according to claim 7 wherein the electromagnets of said one group of electromagnets are disposed to permit operation with odd-lobe vibratory modes.

Claim 10

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said drive means comprises a group of electromagnets, said sensing means comprises a group of electromagnets, and the electromagnets in one group of said groups of electromagnets are spaced from each other by an angle which is not an integer multiple of 90*.

Claim 11

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said electromagnetic drive means comprises a pair of electromagnets, said electromagnetic sensing means comprises a pair of electromagnets, one of said pair of electromagnets being spaced from each other by an angle which is not an integer multiple of 90*, the other of said pair of electromagnets being disposed substantially symmetrically with respect to said first pair of electromagnets, thereby to permit operation with odd-lobe vibratory modes while cancelling magnetic fields induced in said electromagnetic sense means by said electromagnetic drive means.

Claim 12

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said low reluctance path means comprises a magnetic shield cylinder disposed radially outward of said outer pressure cylinder, and at least partially closed at one end and circumscribing a substantial portion of said base member at the other end, said base member and said magnetic shield cylinder being comprised of a high magnetic permeability material, whereby said shield cylinder and said base member provide substantially complete magnetic shielding for said electromagnets and said vibrating cylinder.

Claim 13

A vibrating cylinder pressure transducer subcombination according to claim 11 additionally comprising electronic temperature sensing means disposed on an outer surface of said outer pressure cylinder substantially midway along the axial length thereof, and electrical conductor means passing through said base member between said outer pressure cylinder and said magnetic shield cylinder to provide electrical communication from said electronic temperature sensing means to a point external of said magnetic shielding.

Claim 14

A vibrating cylinder pressure transducer subcombination according to claim 11 wherein said electromagnetic sense means and said electromagnetic drive means include electrical conductor means passing through said base member between said outer pressure cylinder and said magnetic shield cylinder to provide electrical communication from said electromagnetic means to a point external of said magnetic shielding.

Claim 15

A vibrating cylinder pressure transducer subcombination according to claim 1 wherein said base member is completely solid between the confines of the walls of said outer pressure cylinder.

Claim 16

A viBrating cylinder pressure transducer comprising: a base member composed of a high magnetic permeability material; a vibrating cylinder having magnetic permeability, closed at one end and disposed in pressure sealing relationship against said base member at the other end thereof to form a first pressure chamber, said vibrating cylinder composed of material having magnetic permeability; an outer pressure cylinder at least partially closed at one end and disposed in pressure sealing relationship against said base member and surrounding said vibrating cylinder to form a second pressure chamber between said vibrating cylinder and said outer pressure cylinder, said outer pressure cylinder composed of a substantially low magnetic permeability material; inlet means provided for one of said chambers so as to provide fluid communication between one of said chambers and a source of fluid, the pressure of which is to be measured by said transducer; electromagnetic drive means disposed on said outer pressure cylinder and in magnetic communication with said vibrating cylinder; electromagnetic sensing means disposed on said outer pressure cylinder and in magnetic communication with said vibrating cylinder; a magnetic shield cylinder disposed radially outward of said outer pressure cylinder, and at least partially closed at one end and removably disposed with respect to said base member at the other end, said magnetic shield cylinder being composed of a high magnetic permeability material, whereby said shield cylinder and said base provide substantially complete magnetic shielding for said electromagnets and said vibrating cylinder; and circuit means interconnected between said electromagnetic sensing means and said electromagnetic drive means for providing electrical manifestations in response to magnetic variations induced in said electromagnetic sensing means by the vibrations of said vibrating cylinder for inducing electromagnetic force on said cylinder by said electromagnetic drive means, whereby said cylinder establishes self-induced oscillatory operation at a frequency dependent upon a pressure differential across the walls of said vibrating cylinder between said two chambers.

Claim 17

A viBrating cylinder pressure transducer comprising: a base member composed of a high magnetic permeability material; a vibrating cylinder having magnetic permeability, closed at one end and disposed in pressure sealing relationship against said base member at the other end thereof to form a first pressure chamber, said vibrating cylinder composed of material having magnetic permeability; an outer pressure cylinder at least partially closed at one end and disposed in pressure sealing relationship against said base member and surrounding said vibrating cylinder to form a second pressure chamber between said vibrating cylinder and said outer pressure cylinder, said outer pressure cylinder composed of a substantially low magnetic permeability material; inlet means provided for one of said chambers so as to provide fluid communication between one of said chambers and a source of fluid, the pressure of which is to be measured by said transducer; electromagnetic drive means disposed on said outer pressure cylinder and in magnetic communication with said vibrating cylinder; electromagnetic sensing means disposed on said outer pressure cylinder and in magnetic communication with said vibrating cylinder; a magnetic shield cylinder disposed radially outward of said outer pressure cylinder, and at least partially closed at one end and removably disposed with respect to said base member at the other end, said magnetic shield cylinder being composed of a high magnetic permeability material, whereby said shield cylinder and said base provide substantially complete magnetic shielding for said electromagnets and said vibrating cylinder; and circuit means interconnected between said electromagnetic sensing means and said electromagnetic drive means for providing electrical manifestations in response to magnetic variations induced in said electromagnetic sensing means by the vibrations of said vibrating cylinder for inducing electromagnetic force on said cylinder by said electromagnetic drive means, whereby said cylinder establishes self-induced oscillatory operation at a frequency dependent upon a pressure differential across the walls of said vibrating cylinder between said two chambers.

Claim 18

A vibrating cylinder pressure transducer according to claim 15 wherein said circuit means is disposed externally of said magnetic shielding and additionally comprising electronic temperature sensing means disposed on an outer surface of said outer pressure cylinder substantially midway along the axial length thereof, and electrical conductor means passing through said base member between said outer pressure cylinder and said magnetic shield cylinder to provide electrical communication between said electronic temperature sensing means and said circuit means.

Claim 19

A vibrating cylinder pressure transducer according to claim 15 wherein said circuit means is disposed externally of said magnetic shielding and wherein said electromagnetic sense means and said electromagnetic drive means include electrical conductor means passing through said base member between said outer pressure cylinder and said magnetic shield cylinder to provide electrical communication between said electromagnetic means and said circuit means.

Claim 20

A vibrating cylinder pressure transducer according to claim 15 wherein said base member is completely solid within said outer pressure cylinder.

Claim 21

A vibrating cylinder pressure transducer according to claim 15 wherein said electromagnetic drive means comprises a group of electromagnets, said electromagnetic sensing means comprises a group of electromagnets, and the electromagnets in one group of said groups of electromagnets are spaced from each other by an angle of less than 180*, the other group of said groups of electromagnets are disposed substantially symmetrically with respect to said first group of electromagnets, thereby to permit operation with odd-lobe vibratory modes while cancelling magnetic fields induced in said electromagnetic seNse means by said electromagnetic drive means.