Abstract A densitometer which utilizes a thin vane vibrated by a magnetostrictive tube. A piezoelectric crystal pickup feeds an amplifier and tracking filter to energize a driver coil around the magnetostrictive tube. The device is, in effect, an electromechanical oscillator in that the coil is driven in phase with the detected signal. Vibration thus increases in amplitude until limited electrically. A linearization circuit provides an output D.C. voltage directly proportional to fluid density, gas or liquid, which may be impressed upon a conventional D.C. voltmeter calibrated linearly in density. A great many features, both in the mechanical structure and in the electronics, make it possible to easily calibrate the instrument to read, for example, to within an accuracy tolerance of + OR - 0.1 percent over a fluid density range of, for example, from about 0.08 pounds per cubic foot to 80.0 pounds per cubic foot. Another outstanding advantage of the invention relates to a probe-type construction which may be used in a pipeline of any size. Still another feature of the invention resides in the use of a divide-by-two divider to reconcile the driver frequency to the crystal frequency.
Inventors
👤 G Schlatter
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-01 06:02
CPC Classifications
G; G01; G01N; G01N9/00; G01N9/002; G01N2009/008
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
141 words
A vibration densitometer comprising: a base; a structure mounted on said base in a position to be vibrated; a piezoelectric crystal fixed relative to and contiguous to said structure to produce an output signal of a frequency equal to resonant frequency of said structure; a magnetostrictive driver mounted on said base in a position such that, when energized, it can cause said structure to vibrate; and first and second means connected in succession in that order from said crystal to said driver, at least one of said means including an amplifier, said structure, said crystal, said first and second means and said driver forming a closed loop electromechanical oscillator, said amplifier having a gain adequate to sustain vibration of said structure continuously, one of said means including a divide-bytwo divider; and utilization means connected from the output of said first means.
Claim 2
Dependent Claim
141 words
A vibration densitometer comprising: a base; a structure mounted on said base in a position to be vibrated; a piezoelectric crystal fixed relative to and contiguous to said structure to produce an output signal of a frequency equal to resonant frequency of said structure; a magnetostrictive driver mounted on said base in a position such that, when energized, it can cause said structure to vibrate; and first and second means connected in succession in that order from said crystal to said driver, at least one of said means including an amplifier, said structure, said crystal, said first and second means and said driver forming a closed loop electromechanical oscillator, said amplifier having a gain adequate to sustain vibration of said structure continuously, one of said means including a divide-bytwo divider; and utilization means connected from the output of said first means.
Claim 3
Dependent Claim
119 words
The invention as defined in claim 1, wherein said first means includes a differential amplifier, a current-to-voltage converter, a differentiator, a first squarer, an amplitude control, a tracking filter and a second squarer connected in succession from said crystal to said second means, a phase comparator connected from the outputs of said amplitude control and said second squarer, a filter frequency control connected from the output of said comparator to the control input of said filter, said second means including a power amplifier connected to said driver, said second means including said divide-by-two divider connected from said second squarer to said power amplifier, said utilization circuit and an indicator connected in succession from the output of said second squarer.