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

A magnetic flowmeter has a tube for carrying fluid along a longitudinal axis. The tube has faces transverse to the longitudinal axis and disposed at opposite ends of the tube. A liner on the inner surface of the tube extends out from an end of the tube and into a recess on one face to anchor the liner in place.

Flow tube liner

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

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 which includes a flow tube through which the fluid to be metered is conducted, the fluid intercepting a magnetic field to induce a voltage therein which is transferred to a pair of electrodes mounted at diametrically opposed positions on the tube. The inside surface of the meter tube is protectively lined with a stable liner assembly constituted by a three-dimensional stiffening structure embedded in an insulating layer which conforms to the surface.

Insulating liner for electromagnetic flowmeter tube

Circuitry for a device to measure the flowrate of a fluid containing electrical charges which flows in a pipe section. The device includes at least one electromagnet connected to a current source which generates a magnetic field through the pipe section and at least two electrodes whose central imaginary connecting line passes through the flow stream in the region of the magnetic field to measure the potential resulting from the charge displacements. The circuitry also includes a timing circuit which periodically changes the strength of the excitation current from the current source to the electromagnet and switches a signal shunt which is connected between the electrodes and at least two signal memories. The timing circuit also controls a current sink which is connected in parallel with the electromagnet. The two signal memories, which store signals from the electrodes, are connected to a correction circuit to which the signals stored in the memories are supplied to produce an output signal corresponding to the flowrate of the fluid in the pipe section which is only minimally dependent of the flow profile or the level of the fluid in the pipe section.

Apparatus for measuring the flowrate of a fluid

An electromagnetic flowmeter in whose primary the fluid to be metered is conducted through a flow tube to intercept a composite magnetic field to induce therein a voltage which is picked up by capacitive metering electrodes. The composite field is formed by a low-frequency comparison field having a long period on which is superimposed a high-frequency switching field having a short period. The voltage from the capacitive electrodes is fed by way of a high pass filter to the input amplifier of a secondary whose amplified output is analyzed to provide separate components, one originating from the comparison field and the other from the switched field. An output signal is produced in accordance with the time phasing of these components, after compensating for the signal loss experienced in the filter by the comparison field component by means of a compensation voltage derived from the switched field component.

Wilfried Kiene

Papers

Electromagnetic flowmeter with shielded electrodes

Temperature-compensated electromagnetic flowmeter

Insulating liner for electromagnetic flowmeter tube

Apparatus for measuring the flowrate of a fluid

Capacitive type electromagnetic flowmeter