An electromagnetic flow probe for measuring fluid flow, and featuring interchangeable magnet and electrode lumen structures. A complex electrode lead pattern is incorporated in a lumen unit through which the fluid flow is conducted. The magnet structure is equipped with a magnetic field adjustment capability, and adjustable alignment lugs for receiving the lumen unit.

Electromagnetic flow probe

A circuit tester stimulates an analog circuit device under test (DUT) with a test signal and periodically digitizes a resulting DUT output signal to produce an output data sequence that may be analyzed to ascertain DUT operating characteristics. The tester is powered by a switching power supply that induces periodic noise spikes in the DUT output signal. To eliminate the influence of the noise spikes on test results, the period of the switching power supply noise is made coherent with the digitization period. The phase of digitization is then adjusted so that the tester avoids digitizing the noise spikes in the DUT output signal.

Coherent switching power for an analog circuit tester

A highly compact electromagnetic flowmeter unit interposable between the flanged ends of upstream and downstream line pipes for metering fluid passing through the line The flowmeter is constituted by a ferromagnetic ring within which a pair of electromagnet coils is supported at opposed positions along a diametrical axis normal to the longitudinal axis of the ring, the longitudinal axis passing through the central flow passage of an annular pressure vessel The vessel, which is formed of high-strength insulating material, is molded within the ring and encapsulates the coils as well as a pair of electrodes disposed at diametrically-opposed positions with respect to the flow passage along a transverse axis at right angles to the coil axis to define a unitary structure The unit is compressible between the end flanges of the pipes by bridging bolts that pass through bore holes in the pressure vessel or lie outside the ring to encage the unit

Unitary electromagnetic flowmeter

An electromagnetic flowmeter is disclosed in which one of two electrodes (2a, 2b) mounted on a measuring pipe (1) is impressed with an electrical pulse synchronous with the switching of an excitation current, thereby detecting the voltage drop across the electrical resistance of a fluid, so that both the conductivity and the flow rate of the fluid are measureable at the same time.

Electromagnetic flowmeter capable of simultaneous measurement of flow rate and conductivity of fluid

A magnetic flow meter (20) includes a cylindricaL vessel (34) within which electrodes (42) are placed directly opposite each other about a magnetically permeable core (44). In that way, two flow channels are obtained in the vessel. A common magnetic field is applied across both flow channels. The magnetic flow meter (20) is used in conjunction with a controller (100) which monitors amplitude modulated signals representative of applied magnetic field and induced electric field. These amplitude modulated signals are passed to Sigma-Delta modulators, which directly digitise the amplitude modulated AC signals into digital pulses. The controller is capable of monitoring reverse flow through the meter, and to store results until forward flow resumes. Moreover, the controller generates a driving signal for coils (64) which generates a magnetic field, the coil being placed in conjunction with a capacitor (416) which causes resonance. This reduces power consumption by the coil in driving the meter.

Magnetic flow meter

An electromagnetic flowmeter system capable of measuring fluids having any degree of conductivity, including fluids having dielectric properties. The fluid to be measured is conducted through a dielectrically-lined flow tube to intersect a transverse magnetic field produced by an electromagnet, thereby inducing a voltage in a pair of planar electrodes mounted within the dielectric lining, each electrode being provided with a driven shield. The electromagnet is excited by a direct voltage which is periodically interrupted to produce a periodic steady state field whereby unwanted in-phase and quadrature components are minimized.

Electromagnetic flowmeter with shielded electrodes

An electromagnetic flowmeter in which the fluid to be metered is conducted through a flow tube provided with a pair of diametrically-opposed electrodes. The fluid intercepts a magnetic field established in the flow tube by a magnetizable core having a coil wound thereon through which an excitation current flows, thereby inducing a signal voltage in the electrodes. Because the permeability of the core is temperature-dependent, changes in temperature affect the strength of the magnetic field and adversely influence the signal voltage. Compensation means are provided to render the signal voltage independent of temperature, thereby producing an output signal accurately proportional to flow rate.

Temperature-compensated electromagnetic flowmeter

An electromagnetic flowmeter system whose electromagnets are excited by a direct-current source through switching means operating at a predetermined drive frequency to generate a pulsatory current establishing a magnetic flux field in the flow tube through which the fluid to be measured is conducted. The fluid intercepting this field induces a pulsatory voltage in the metering electrodes mounted at diametrically-opposed positions on the tube. The electrode voltage is applied to an analyzer which includes a sampling switch operating in synchronism with the drive frequency to extract pulses from the electrode voltage during the magnetic flux steady state intervals thereof. These pulses, which are rich in harmonics, are fed through a filter that selects one of the harmonics to yield a harmonic signal which is demodulated to produce an output signal free of disturbances.

Electromagnetic flowmeter system

Flaechige mess- und schirmelektroden fuer kapazitiven signalabgriff bei einem induktiven durchflussmesser

A balancing circuit interposed between a primary electromagnetic flowmeter, wherein fluid to be measured passes through a flow tube to intersect a transverse magnetic field to induce a signal in electrodes projecting into a tube, and an amplifier responsive to this signal. The balancing circuit is adapted to compensate for quadrature voltage induced in the leads extending from the electrodes whereby the signal applied to the amplifier is free of quadrature voltage and accurately reflects flow rate.

Gottfried Geisler

Papers

Electromagnetic flowmeter with shielded electrodes

Temperature-compensated electromagnetic flowmeter

Electromagnetic flowmeter system

Flaechige mess- und schirmelektroden fuer kapazitiven signalabgriff bei einem induktiven durchflussmesser

Quadrature-voltage balancing circuit or electromagnetic flowmeter