Abstract: A load applied to a load cell's load-bearing member (21) causes that member to move against the force applied by springs (28 and 30) and thereby bring a magnet (24) into closer proximity to the ferromagnetic core (12) of a coil (10). Acting across a small gap, the magnet partially saturates a magnetic circuit that encloses the coil. This force-caused magnet motion changes the coil inductance and the magnetic circuit's degree of saturation. By applying to the coil (10) a brief voltage pulse without thereby heating it significantly, and by observing the coil current's resultant steady-state value and the rate at which the coil current approaches that value, an inductance-to-load converter (FIG. 4) calculates the applied load and the coil's temperature and generates outputs that represent them.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A permanent magnet (42) mounted on the diaphragm (30) so moves with diaphragm flexure as to vary the magnetic saturation of a saturable circuit in which the coil (34) generates flux. By determining the coil's inductance under quiescent-diaphragm conditions, a computer (56) can infer the ambient pressure that bears upon the liquid (10). By compensating for the static pressure thus inferred, it can then determine liquid level by observing diaphragm oscillations reflected in coil electromotive force generated by the magnet (42) as the diaphram (30) undergoes oscillatory flexure in response to the coil's momentary excitation.

Abstract: A load applied to a load cell's load-bearing member (21) causes that member to move against the force applied by springs (28 and 30) and thereby bring a magnet (24) into closer proximity to the ferromagnetic core (12) of a coil (10). Acting across a small gap, the magnet partially saturates a magnetic circuit that encloses the coil. This force-caused magnet motion changes the coil inductance and the magnetic circuit's degree of saturation. By applying to the coil (10) a brief voltage pulse without thereby heating it significantly, and by observing the coil current's resultant steady-state value and the rate at which the coil current approaches that value, an inductance-to-load converter (FIG. 4) calculates the applied load and the coil's temperature and generates outputs that represent them.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A permanent magnet (42) mounted on the diaphragm (30) so moves with diaphragm flexure as to vary the magnetic saturation of a saturable circuit in which the coil (34) generates flux. By determining the coil's inductance under quiescent-diaphragm conditions, a computer (56) can infer the ambient pressure that bears upon the liquid (10). By compensating for the static pressure thus inferred, it can then determine liquid level by observing diaphragm oscillations reflected in coil electromotive force generated by the magnet (42) as the diaphram (30) undergoes oscillatory flexure in response to the coil's momentary excitation.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A strain gauge (46) detects the diaphragm flexure, and analysis circuitry (62) determines the liquid level as a function of the resultant oscillation frequency and the diaphragm's static flexure.

Abstract: A densitometer (10) provides a chamber (24) within which a ferromagnetic bob (27) is shuttled back and forth by alternate driving of two coils (32 and 34). Measurement circuitry (FIG. 2) determines the density of the fluid inside the chamber (24) by comparing the stroke times in opposite directions.

Abstract: A viscometer (10) includes a chamber-defining cylinder (22) within which a bob (26), including a ferromagnetic collar (30), is shuttled back and forth by alternate driving of two coils (32 and 34). Measurement circuitry (FIG. 2) determines the viscosity of fluid inside the chamber (24) by measuring the time required for the bob (26) to make a round trip consisting of one stroke in each direction. By employing round-trip time rather than single-stroke time, the viscometer (10) reduces the sensitivity of the viscosity measurement to orientation with respect to gravity.

Abstract: A viscometer (10) employs a tube (12) with a check valve (30) at one end and a ferromagnetic bobbin (16) disposed inside and freely movable with respect to it. A pair of coils (38 and 40) are alternately energized, causing the bobbin (16) to move against fluid in the tube in one direction, in which the check valve (30) prevents fluid flow, and in the other direction, in which the check valve (30) permits fluid flow within the tube. When the bobbin (16) moves in the direction in which the check valve (30) permits flow, it draws a new sample of fluid into the tube, and the time required for the bobbin (16) to move in the other direction, in which fluid flow is prevented by the check valve (30), is measured as an indication of the viscosity of the fluid. The position of the bobbin is sensed by measuring the mutual inductance between the coils (38 and 40).

Abstract: This disclosure deals with measuring either discontinuous or continuous impedance transitions in various media to identify or delineate the properties and nature thereof by transmitting radiant energy waves to such media to produce reflected waves therefrom, deconvoluting the outgoing and returning waves, and integrating the resulting reflection impulse-response function so as to enable appropriate interpretation of the resulting display for identification and related purposes.

Abstract: Acoustic impedance transitions in human or animal bodies or other media are measured for identification and diagnostic purposes by exposing the body to acoustic energy pulses to produce echo pulses which are detected. The echo pulses are processed to indicate the relative specific acoustic impedance of the exposed body as a function of the time/distance relationship of the echo pulses relative to the medium, thereby to enable the determination of the relative extent and position of irregularities in the body, for example.