Abstract: A liquid flow measuring system which, by means of a suitable timing sequence, is able to detect unbalanced voltage generation which occurs when the tube element through which the liquid is flowing is not completely full and, by means of a correction process, supplies an output signal which is proportional to the rate of flow. When the tube element is full, the system operates in the same way as a normal magnetically inductive flowmeter. If the level in the tube element falls, electrodes which are installed in the lower half of the tube element and other electrodes, if necessary, can be used exclusively or additionally to record the measured values. Moreover, with a view to improving the recording of measured values when the level falls below a specific limit, an arrangement of electromagnets, specially optimized for partially filled tube elements, can be activated instead of the normal arrangement of electromagnets.

Abstract: Fluid flowrate measuring apparatus in which magnet coils, positioned symmetrically about a pipe through which fluid flows, are excited to generate magnetic fields during four periods of an excitation cycle which are additive during the first period of excitation, opposing during the second period of excitation, additive during the third period of excitation in an opposite sense to that during the first period, and opposing during the fourth period of excitation in an opposite sense to that during the second period. Electrodes, which sense fluid flow through the magnetic fields, develop signals representative of fluid flow through the pipe during the four excitation periods and these signals are processed to develop a flowrate measurement signal.

Abstract: A device to measure the flowrate of electrically charged fluids consisting of a pipe section through which the fluid flows which contains at least two current sources connected to electromagnets, which generate a magnetic field which extends through the pipe section, and which contains for the measurement of the electrical potential due to the charge differential at least two electrodes, whose axes are connected by an imaginary line which extends through the fluid flow, and which electrodes are connected to a correction circuit which produces an output signal proportional to the flowrate which is only minimally influenced by the flow profile and/or the level of the fluid in the pipe section characterized by electromagnets which are excited from the current sources by different frequencies and that between the electrodes and the correction circuit are connected parallel to each other band pass filters corresponding to the different frequencies, and connected after these band pass filters are dc rectifiers cont

Abstract: 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.

Abstract: A magnetic flowmeter which generates a signal proportional to the flow rate of a fluid passing through a pipe to intersect a magnetic field whose lines of flux are substantially parallel to a transverse axis normal to the longitudinal axis of the pipe. The flowmeter includes two electrode assemblies mounted on the pipe on opposite sides of the transverse axis and capacitively coupled to the fluid. The effective coupling capacity of the electrodes in each assembly is such as to render the signal substantially immune to the influence of non-axisymmetric flow profiles.

Abstract: 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.

Abstract: An electromagnetic flowmeter in which the fluid to be metered is conducted through a flow tube formed of nonmagnetizable metal and provided with an inner lining of electrical-insulating material. The fluid intercepts a transverse electromagnetic field established in the tube whereby the voltage induced in the fluid is transferred to a pair of electrodes disposed at diametrically-opposed positions on the tube to yield a signal indicative of flow rate. The electromagnet is constituted by at least one solid core surrounded by a coil to which a low-frequency excitation current is applied, the core having a cavity in a region therein which serves to reduce the mass of the core without, however, significantly affecting the intensity of the magnetic field produced thereby.

Abstract: 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.