Auburn International, Inc.

Oxford Instruments America, Inc.

Robert E Newton

Ronald L Dechene

Frank G Grimaldi

David R Day

Russell S Girgenti

Ron L Swartzentruber

Thomas B Smith

John Merk

Conditions in a fluidized bed are measured with a probe and a circuit. The bed can be a polymerization reactor's reaction chamber, and the conditions can result in 'sheeting' which is the build up of polymer on the chamber walls. The probe protrudes into the bed and detects a current which generally is a function of at least the impact and charge of particulates in the bed. The current detected by the probe is related to the conditions in the bed. The circuit measures the detected current. The probe has an inner probe piece of metallic material within an insulator of polymeric material. A portion of the insulator protrudes a first distance into the bed, and a portion of the inner probe piece protrudes a second distance into the bed. The first distance is less than or equal to the second distance. The insulator typically does not extend as far into the bed as the inner probe piece.

Apparatus and method for measuring conditions in fluidized beds

An improved invasive acoustic sensor apparatus detects particulate matter in a flow by impingement thereon. The apparatus includes an axially extending probe body having an active length positionable in a flow and a distributed piezoelectric transducer disposed therein. The transducer is acoustically coupled to an interior surface of the body, along substantially the entire active length thereof, and may be a piezoelectric film, piezoelectric tube, or a plurality of electrically parallel connected piezoelectric tube elements. The apparatus further includes an acoustic isolation layer disposed between the probe body and positioning structure to reduce transmission of process wall vibration to the transducer.

Acoustic sensing

A microprocessor (48) controlled triboelectric instrument with probe fouling detection, zero offset adjustments and temperature compensation. The system programmability provides for enhanced operator control and operator monitoring wherein the system may be reprogrammed to advantage to reduce instrument down time.

Triboelectric instrument with DC drift compensation

An improved input circuit (9) for accepting a signal from a triboelectric probe (2). The circuitry provides gain, zero and probe contamination information which allows verification of said information without taking the probe and instrument off-line.

On line triboelectric probe contamination detector

Monitoring apparatus (10) of particles in a gas stream comprising a probe (12) and circuit (14) for detecting electrical activity of the probe and an actuator (20) for insertion and retraction of the probe into and out of the stream, the circuit providing periodic measurement of the retracted probe and self-adjustment to compensate for changing probe characteristics. The apparatus also provided probe cleaning and protection means (30, 32, 34, 36), which work in interaction with the self-check instrumentation. The self-check tests include baseline, gain and sensitivity monitoring.

Long term particle monitoring

Particle analysis apparatus (10) in combination with a triboelectric probe (P) and including means (18, 20, 22, 24, 26) to analyze individual particle collisions with the probe as a useful measure of flow conditions--of a fluid with suspended solid particles--in the region of the probe.

Flow measurement by collision characterization

Flow measuring apparatus comprising a probe (1) coupled via a coaxial cable (2) to control circuitry with a current to voltage convertor (10), absolute value circuit (12), auto zero switch and integration (11, 27) and voltage to current circuit (18) yielding an analog output, corresponding to flow at the probe.

Flow measuring apparatus with analog, essentially linear output

Airborne dust concentration in a silo or the like is measured by inducing flow in one or more Venturi nozzles (10) located in the area of airborne dust. A triboelectric sensor probe electrode (20) is located at the nozzle inlet section (12) and flow is induced by a feed of inductive air through an annular channel located in the wall of the nozzle downstream of the electrode.

Dust flow inducing monitor

Measuring of mixed phased flows to determine flow regime through the use of circumferentially shifted electric fields and measurement of resultant diametral and chord conductances with certain combinations of ratios of diametral to cord conductances serving as a signature of flow regime.

Flow regime detecting

Liquid with solid or gas phases mixed therein is measured as to liquid and non-liquid volume percent by application of an oscillating voltage to the liquid and separation of resultant conductive and capacitive currents to achieve valid and effective measurement of the latter, unmasked by the larger conductive currents obtainable in the mixed phase medium analyzed.

Electrical measurement of fluid void fraction for fluid having

The relative amounts of liquid phase versus vapor phase of a mixed phase resistively conductive fluid, such as boiling water, is determined by an indirect measurement of admittance between a poled pair of electrodes within a cross section of a flow path in the fluid comprising part of an electrical circuit by providing an oscillating power source therein with an alternating voltage on the order of 1-30 kilohertz across the electrode pair generating a voltage drop across a load resistance in the loop which electric parameter varies as a function of admittance in the fluid between electrodes--as affected by liquid void fractions therein, the voltage drop signal so produced being divided by a similar voltage drop which varies as a function of admittance of liquid from the same fluid to determine liquid fraction (and by subtraction from unity, vapor fraction), with compensation for conductivity change, the measuring process further including the isolation of reactive and resistive cross conduction outside the measurement loop.

Vapor/liquid fraction determination

The relative amounts of liquid phase versus vapor phase of a mixed phase nonconductive fluid such as oil or fuel; or the relative amounts of solids versus gas of a mixed flow of nonconductive particles and gas such as pneumatically conveyed plastic pellets and other material is determined by capacitive measurement taken in several distributed directions overlapping within the cross section of a flow path by providing a rotating electric field therein with an alternating voltage on the order of 10-100 kilohertz, with capacitive measurement produced by the rotated field being proportional to the liquid or solid fraction (and by subtraction from unity, vapor or gas fraction), the rotating electrical field being produced by sequentially rotating the electrical position of six plates equally spaced around the periphery of the cross section to be measured, the plate structure and insulations defining a flow measuring cross section or being spaced on the outer periphery of a nonconductive flow tube with allowance for rigors of flow conditions and fluid environment to provide reliable, long life.

Nonconductive vapor/solid or liquid fraction determination

The relative amounts of liquid phase versus vapor phase of a mixed phase conductive fluid, such as boiling water, is determined by conductivity measurement taken in several distributed directions overlapping within the cross section of a flow path by providing a rotating field vector therein with an alternating voltage on the order of 1-30 kilohertz, with conductivity measurement produced by the rotated field being divided by a liquid conductivity measurement to determine liquid fraction (and by subtraction from unity, vapor fraction), the rotating electrical field being produced by application of a multi-phase alternating current to groups of electrodes with poled pairs distributed in alternation around the periphery of the cross section to be measured, the electrode structure and intervening insulators defining a flow measuring cross section with allowance for rigors of flow conditions and fluid environment to provide reliable, long-lived effective measurement.

Growing community of inventors

Tewksbury, MA, United States of America

Robert E Newton