US3585843A — Fluid density transducers

Claim 1

Independent Claim 266 words

A fluid density transducer comprising a right circular cylindrical tube formed of resilient ferromagnetic material, a pair of end blocks each with a conical hole therethrough, the blocks being arranged with the holes coaxial and having the wide ends of the holes facing one another, a pair of internal flanges, one in each of the said holes at the narrow end thereof, the ends of the tubes being located and secured respectively in the apertures of the said internal flanges, a supporting structure, a pair of pipe connections fixed in the supporting structure, a pair of bellows assemblies respectively coupling the ends of the tube to the said pipe connections, each bellows assembly comprising a metal outer sheath member and an inner elastomeric member having a bore aligned with and equal to that of the tube, mounting means to mount the said end blocks on the supporting structure with compliance axially of the tube but substantially rigidly transversely of the tube, a drive coil and two pickup coils mounted on a platform resiliently suspended between the said end blocks, and maintaining amplifier means coupling the said pickup coils to the said drive coil, the drive coil being arranged to excite a central antinode in the tube at an overtone frequency and the pickup coils being arranged to sense two other antinodes symmetrically disposed in the tube relative to the said central antinode, the said amplifier means being adapted to provide in operation a vibration-maintaining phase difference between the currents flowing through the drive coil on the one hand and the pickup coils on the other hand.

Claim 2

Dependent Claim 266 words

A fluid density transducer comprising a right circular cylindrical tube formed of resilient ferromagnetic material, a pair of end blocks each with a conical hole therethrough, the blocks being arranged with the holes coaxial and having the wide ends of the holes facing one another, a pair of internal flanges, one in each of the said holes at the narrow end thereof, the ends of the tubes being located and secured respectively in the apertures of the said internal flanges, a supporting structure, a pair of pipe connections fixed in the supporting structure, a pair of bellows assemblies respectively coupling the ends of the tube to the said pipe connections, each bellows assembly comprising a metal outer sheath member and an inner elastomeric member having a bore aligned with and equal to that of the tube, mounting means to mount the said end blocks on the supporting structure with compliance axially of the tube but substantially rigidly transversely of the tube, a drive coil and two pickup coils mounted on a platform resiliently suspended between the said end blocks, and maintaining amplifier means coupling the said pickup coils to the said drive coil, the drive coil being arranged to excite a central antinode in the tube at an overtone frequency and the pickup coils being arranged to sense two other antinodes symmetrically disposed in the tube relative to the said central antinode, the said amplifier means being adapted to provide in operation a vibration-maintaining phase difference between the currents flowing through the drive coil on the one hand and the pickup coils on the other hand.

Claim 3

Dependent Claim 107 words

A fluid density transducer comprising a tube formed of resilient material, first and second massive clamping means fixedly attached to the ends of said tube for establishing node points defining a vibratable tube portion having a natural resonant frequency f, means for introducing into said tube a fluid the density of which is to be measured, means for exciting natural transverse vibration of said tube at an overtone frequency of at least about 2f, the exact frequency of vibration being representative of the density of said fluid; and means for sensing the resulting frequency of vibration and for displaying said frequency as a measure of fluid density.

Claim 4

Dependent Claim 107 words

A fluid density transducer comprising a tube formed of resilient material, first and second massive clamping means fixedly attached to the ends of said tube for establishing node points defining a vibratable tube portion having a natural resonant frequency f, means for introducing into said tube a fluid the density of which is to be measured, means for exciting natural transverse vibration of said tube at an overtone frequency of at least about 2f, the exact frequency of vibration being representative of the density of said fluid; and means for sensing the resulting frequency of vibration and for displaying said frequency as a measure of fluid density.

Claim 5

Dependent Claim 106 words

Apparatus according to claim 2 wherein each of said clamping means comprises a substantially cylindrical body having a central bore greater in diameter than the greatest transverse excursion of said tube, and a radially inwardly extending flange at one end of said bore, said flange defining an inner bore having a diameter equal to the outer diameter of said tube, said flange having an axial thickness significantly smaller than the inner diameter of said tube, said body being mounted on said tube with said flange being attached to the end of said tube and said bore surrounding a portion of the vibrating portion of said tube.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-06-21	1974-12-21	1975-06-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-06-21	1978-12-21	1979-06-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-06-21	1982-12-21	1983-06-22	$7700.00	Window Closed / Lapsed

Fluid density transducers

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