US 4,524,610 A · In-line vibratory viscometer-densitometer

Abstract

A rotational vibratory viscometer-densitometer for in-line process control and similar applications, having an elastic hollow metal tube extending between two clamps, and a relatively rigid transverse yoke secured to the tube at a point midway between the clamps. The yoke has magnetically permeable ends and a magnetically permeable center portion. Electromagnets adjacent one end of the yoke and the center portion thereof interact with the yoke to cause the tube to oscillate simultaneously in torsion and in flexure at the natural frequency of the tube in combination with the fluid within it. The amplitude of torsional oscillation is maintained constant by a torsional detector and control circuit, and the power required to maintain said amplitude is determined, said power being a measure of the viscosity of the fluid flowing through the tube. The frequency of flexural oscillation of the tube is determined by a flexural detector and associated circuit, said frequency being a measure of the density of the fluid flowing through the tube.

Claims24

Dependent claims

A transducer assembly for an in-line vibratory viscometer, comprising:

a tube exhibiting elasticity, through which tube a fluid may flow;
means for securing first and second longitudinally spaced sections of said tube to provide oscillation nodes at said sections;
a transverse yoke secured to a third section of said tube intermediate said first and second sections thereof;
drive means comprising means operatively associated with said yoke for exciting and maintaining a torsional mode of oscillation of said tube beween said nodes, said drive means also including independently controllable means operatively associated with said yoke for exciting and maintaining a flexural mode of oscillation of said tubes between said nodes;
torsional detector means for detecting said torsional oscillation;
means coupled to said drive means and said torsional detector means for providing a viscosity-density product output signal indicative of the viscosity-density product of any fluid within said tube;
and
flexural detector means responsive to the flexural oscillation of said tube.

5 more elements

An in-line vibratory viscometer, comprising:

a transducer having:
a tube extending elasticity, through which a fluid may flow
means for securing first and second longitudinally spaced sections of said tube to provide oscillation nodes at said sections,
a transverse yoke secured to a third section of said tube intermediate said first and second sections thereof,
drive means comprising means operatively associated with said yoke for exciting and maintaining torsional oscillation of said tube between said nodes, and
detector means for detecting said torsional oscillation;
first circuit means connected between said drive means and said detector means for providing a torsional oscillation mode control signal to said drive means to maintain said tube in torsional oscillation at substantially the natural frequency thereof and at a predetermined constant amplitude;
and
second circuit means coupled to said drive means and said detector means for providing a viscosity-density product output signal indicative of the viscosity-density product of any fluid within said tube, said viscosity-density product output signal corresponding to the power required to sustain a predetermined angular amplitude of torsional mode oscillation of said tube with said fluid therein.

6 more elements

Dependencies are inferred from the claim text.

In-line vibratory viscometer-densitometer

Life of this patent

In-line vibratory viscometer-densitometer

Life of this patent

Abstract

Claims24