Densitometer

Claim 2

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said structure including a main cylinder and a vane in the shape of a substantially flat plate of uniform thickness, said vane passing approximately through the axis of said main cylinder from one side thereof to the other, first means to clamp both of the edges of said vane contiguous to the internal surface of said main cylinder, said first means being fixed relative to said main cylinder, the internal surface of said first means being substantially cylindrical and concentric with that of said main cylinder, said main cylinder having a substantially uniform thickness around its circumference, second means to vibrate said first means at a point approximately midway along its length, and at a point spaced about 90 mechanical degrees around said main cylinder from one longitudinal edge of said vane, third means to sense vibrations of said vane and fourth means connected from said third means to produce an output signal in accordance with the density of fluid surrounding said vane.

Claim 3

The invention as defined in claim 1, wherein said probe includes an outer cylinder having an axis approximately perpendicular to that of said main cylinder and extending approximately through said main cylinder axis approximately at its midpoint, one end of said outer cylinder being fixed relative to said main cylinder, a magnetostrictive inner tube inside said outer tube, said outer tube having an inwardly extending annular shoulder, said inner tube having an outwardly extending annular shoulder between said first means and said outer tube shoulder in engagement with said outer tube shoulder, said inner tube having one end in engagement with said first means, a solenoid winding around said inner tube inside said outer tube fixed to said inner tube, said winding being located between said first means and said outer tube shoulder, said inner tube always being in axial compression between said first means and said outer tube shoulder whether or not said winding is energized, fifth means between the ends of said inner and outer tubes, said inner and outer tubes and said fifth means all being made of a magnetic material and being located contiguous to each other to form a substantially closed magnetic circuit around said winding, a piezoelectric crystal fixed to said vane approximately at the center of one longitudinal edge thereof, said crystal and said winding each having a pair of lead wires, said crystal lead wires extending through the center of said inner tube, said winding lead wires extending in the space between said inner and outer tubes, sixth means to energize said winding with a signal in phase with the output of said crystal at the first resonant frequency, seventh means responsive to the output of said crystal for producing an output signal directly proportional to (A/f2) + B where, f is the first resonant frequency, and A and B are constants, and eight means including D.C. voltmeter calibrated linearly in density to indicate the magnitude of said seventh means output signal.

Claim 4

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said structure being in the shape of a thin walled hollow cylinder, and a vane fixed longitudinally inside said cylinder, said vane extending approximately through the axis of said cylinder, said cylinder wall having a thickness small in comparison to its diameter, said vane having its longitudinal edges fixed relative to said cylinder and being otherwise unsupported between said edges, said vane being adapted to vibrate over the unsupported portion thereof, means to vibrate said vane, means to sense vibrations of said vane, and means connected from said sensing means to produce an output signal in accordance with the density of fluid surrounding said vane.

Claim 5

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said structure being in the shape of a thin walled hollow cylinder, and a vane fixed longitudinally inside said cylinder, said vane extending approximately through the axis of said cylinder, said cylinder wall having a thickness small in comparison to its diameter, said vane having its longitudinal edges fixed relative to said cylinder and being otherwise unsupported between said edges, said vane being adapted to vibrate over the unsupported portion thereof, means to vibrate said vane, means to sense vibrations of said vane, and means connected from said sensing means to produce an output signal in accordance with the density of fluid surrounding said vane.

Claim 6

The invention as defined in claim 3, including two half cylinders inside said hollow cylinder to clamp the axially extending edges of said vane, said vibrating means comprising means to vary the strain of one of said half cylinders by applying an undulating force at a point approximately midway along the length of the external surface thereof and approximately midway therearound.

Claim 7

The invention as defined in claim 3, wherein both circular edges of said cylinder at the ends thereof are rounded.

Claim 8

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said probe including inner and outer hollow tubes, said structure being fixed relative to the end of said outer tube, said tubes both being made of magnetic materials, a detector for producing an electrical signal in accordance with the vibration of said structure, a solenoid winding between said tubes around said inner tube, said inner tube being magnetostrictive, said detector having a pair of lead wires extending from said one probe end through the hollow interior of said inner tube, said winding having a pair of leads extending away from said one probe end in the space between said tubes, first means to provide a magnetic circuit surrounding the end of said inner tube at the other end of said probe, said first means defining an enclosed housing space, an electrical circuit in said housing space, said detector lead wires being connected to said circuit, said first means providing a completely closed magnetic circuit except for one hole therethrough, said circuit having output leads extending through said hole, said inner tube being adapted to move and vibrate said structure responsive to the flow of a fluctuating current in said solenoid winding.

Claim 9

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said probe including inner and outer hollow tubes, said structure being fixed relative to the end of said outer tube, said tubes both being made of magnetic materials, a detector for producing an electrical signal in accordance with the vibration of said structure, a solenoid winding between said tubes around said inner tube, said inner tube being magnetostrictive, said detector having a pair of lead wires extending from said one probe end through the hollow interior of said inner tube, said winding having a pair of leads extending away from said one probe end in the space between said tubes, first means to provide a magnetic circuit surrounding the end of said inner tube at the other end of said probe, said first means defining an enclosed housing space, an electrical circuit in said housing space, said detector lead wires being connected to said circuit, said first means providing a completely closed magnetic circuit except for one hole therethrough, said circuit having output leads extending through said hole, said inner tube being adapted to move and vibrate said structure responsive to the flow of a fluctuating current in said solenoid winding.

Claim 10

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said structure being a substantially rectangular vane, first means to clamp the opposite longitudinal edges of said vane, said probe including a longitudinal member, said structure and said first means being mounted on said member, second means to vibrate said vane, third means to sense vibrations of said vane, and fourth means connected from said third means to produce an output signal in accordance with the densiTy of fluid surrounding said vane.

Claim 11

A vibration densitometer comprising: a probe having a structure adapted to be vibrated at one end thereof, said structure being a substantially rectangular vane, first means to clamp the opposite longitudinal edges of said vane, said probe including a longitudinal member, said structure and said first means being mounted on said member, second means to vibrate said vane, third means to sense vibrations of said vane, and fourth means connected from said third means to produce an output signal in accordance with the densiTy of fluid surrounding said vane.

Claim 12

The invention as defined in claim 7, wherein said first means includes two half cylinders and a ring around said half cylinders, said ring and half cylinders with said vane therebetween having an interference fit.

Claim 13

The invention as in claim 8, wherein said third means comprises a detector positioned against one clamped edge of said vane, and said second means vibrates one half cylinder at a point therearound approximately 90* about the axis of said ring from said detector.

Claim 14

The invention as defined in claim 9, wherein said second means includes third means responsive to an electrical signal to vibrate said one half cylinder, fourth means for impressing an alternating signal on said third means in phase with the output of said detector, said fourth means being connected from said detector.

Claim 15

The invention as defined in claim 10, including fifth means connected from said detector to produce an output signal which is a function of the frequency of the output signal of said detector.

Claim 16

The invention as defined in claim 11, wherein said detector is a device to produce an electrical signal in accordance with pressure changes thereon.

Claim 17

The invention as defined in claim 12, wherein said detector is a piezoelectric crystal.

Claim 18

The invention as defined in claim 13, wherein said crystal is disposed midway along the length of said vane.

Claim 19

The invention as defined in claim 7, including a pipe, said pipe having a hole through the wall thereof, said probe longitudinal member extending through said hole, said vane being located inside said pipe substantial in a plane parallel to the pipe axis but perpendicular to the axis of said member, second means to provide a fluid tight seal between said member and the edges of said pipe hole.

Claim 20

The invention as defined in claim 15, wherein said second means resiliently mounts said probe in said pipe hole.

Claim 21

The invention as defined in claim 16, wherein said member has an outer cylindrical surface, said second means including two O-rings, said second means being everywhere spaced from the said outer surface of said member except that each of said O-rings lie in fluid tight sealing and supporting contact with the outer surface of said member at two respective spaced circular lines of contact therewith.

Claim 22

A vibration densitometer comprising: a probe including a body; a hollow outer cylinder fixed relative to said body; a hollow inner cylinder having at least an approximately cylindrical internal bore and bore axis, said inner cylinder being fixed relative to and contiguous to said outer cylinder inside thereof and concentric therewith; a substantially flat, rectangular vane having a substantially uniform thickness between approximately parallel planes, the thickness of said vane being small in comparison to the length and width thereof, said vane having its longitudinal edges supported in fixed positions relative to said inner cylinder inside thereof, said vane extending generally diametrically across said inner cylinder bore through said bore axis, said outer cylinder having a hole extending therethrough in a predetermined direction approximately perpendicular to said planes; a piezoelectric crystal fixed between said cylinders against one of said vane edges approximately at the midpoint thereof; a magnetostrictive member, said member extending in said predetermined direction from a first position spaced from the external cylindrical surface of said outer cylinder a distance from said bore axis greater than the radius of said cylinder external surface, said member extending from said first position loosely through said hole to a second position at a predetermined portion of the external cylindrical surface of said inner cylinder accessible through said hole, said member having one end at said second position in contact with said surface portion; loading means fixed relative to said body and engaging said member at said first position, said loading Means holding said member in axial compression with said end thereof in pressure contact with said surface portion, a winding around said member between said first and second positions; utilization means having an input; first means connecting said crystal to said utilization means input, said first means having an output connected to said utilization means input; and second means connected from said first means output to said winding to impress a predetermined voltage thereon having at least an A.C. component with a predetermined phase and predetermined frequency the same as those of the output voltage of said crystal, the application of said predetermined voltage to said winding causing the strain in said member, said inner cylinder, said outer cylinder and said vane to vary said vane vibrating in accordance with said varying strain, said crystal detecting said vane vibration, said vane, said crystal, said first means, said second means, said winding and said member acting as a closed loop electromechanical oscillator with the feedback signal being produced by said crystal, at least one of said first and second means including an amplifier, the gain of said loop being adequate to sustain vibration of said vane continuously.

Claim 23

A vibration densitometer comprising: a probe including a body; a hollow outer cylinder fixed relative to said body; a hollow inner cylinder having at least an approximately cylindrical internal bore and bore axis, said inner cylinder being fixed relative to and contiguous to said outer cylinder inside thereof and concentric therewith; a substantially flat, rectangular vane having a substantially uniform thickness between approximately parallel planes, the thickness of said vane being small in comparison to the length and width thereof, said vane having its longitudinal edges supported in fixed positions relative to said inner cylinder inside thereof, said vane extending generally diametrically across said inner cylinder bore through said bore axis, said outer cylinder having a hole extending therethrough in a predetermined direction approximately perpendicular to said planes; a piezoelectric crystal fixed between said cylinders against one of said vane edges approximately at the midpoint thereof; a magnetostrictive member, said member extending in said predetermined direction from a first position spaced from the external cylindrical surface of said outer cylinder a distance from said bore axis greater than the radius of said cylinder external surface, said member extending from said first position loosely through said hole to a second position at a predetermined portion of the external cylindrical surface of said inner cylinder accessible through said hole, said member having one end at said second position in contact with said surface portion; loading means fixed relative to said body and engaging said member at said first position, said loading Means holding said member in axial compression with said end thereof in pressure contact with said surface portion, a winding around said member between said first and second positions; utilization means having an input; first means connecting said crystal to said utilization means input, said first means having an output connected to said utilization means input; and second means connected from said first means output to said winding to impress a predetermined voltage thereon having at least an A.C. component with a predetermined phase and predetermined frequency the same as those of the output voltage of said crystal, the application of said predetermined voltage to said winding causing the strain in said member, said inner cylinder, said outer cylinder and said vane to vary said vane vibrating in accordance with said varying strain, said crystal detecting said vane vibration, said vane, said crystal, said first means, said second means, said winding and said member acting as a closed loop electromechanical oscillator with the feedback signal being produced by said crystal, at least one of said first and second means including an amplifier, the gain of said loop being adequate to sustain vibration of said vane continuously.

Claim 24

The invention as defined in claim 18, wherein said cylinders have an interference fit.

Claim 25

The invention as defined in claim 18, wherein a hollow outer tube is fixed relative to said body in a position surrounding said magnetostrictive member and said winding, said outer tube being spaced from said member to accommodate said winding over the length thereof.

Claim 26

The invention as defined in claim 20, wherein said outer tube is positioned contiguous to said member at each end of said winding, said outer tube being made of a magnetic material to complete a magnetic circuit from two points on said member beyond each end of said winding.

Claim 27

The invention as defined in claim 21, wherein one end of said outer tube is fixed relative to and sealed to the external cylindrical surface of said outer cylinder around said hole therethrough.

Claim 28

The invention as defined in claim 22, wherein said magnetostrictive member is a hollow inner tube, said crystal having a pair of leads extending from between said cylinders through the interior of said inner tube to said first means.

Claim 29

The invention as defined in claim 21, wherein said magnetostrictive member is a hollow inner tube, said crystal having a pair of leads extending from between said cylinders through the interior of said inner tube to said first means.

Claim 30

The invention as defined in claim 21, wherein one end of said outer tube is fixed relative to said outer cylinder around said hole therethrough.

Claim 31

The invention as defined in claim 20, wherein one end of said outer tube is fixed relative to and sealed to the external cylindrical surface of said outer cylinder around said hole therethrough.

Claim 32

The invention as defined in claim 26, wherein said magnetostrictive member is a hollow inner tube, said crystal having a pair of leads extending from between said cylinders through the interior of said inner tube to said first means.

Claim 33

The invention as defined in claim 20, wherein said magnetostrictive member is a hollow inner tube, said crystal having a pair of leads extending from between said cylinders through the interior of said inner tube to said first means.

Claim 34

The invention as defined in claim 28, wherein one end of said outer tube is fixed relative to said outer cylinder around said hole therethrough.

Claim 35

The invention as defined in claim 29, wherein said outer tube is positioned contiguous to said member at each end of said winding, said outer tube being made of a magnetic material to complete a magnetic circuit from two points on said member beyond each end of said winding.