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Lennart Thegel

Sten Linder

Thomas Liljenberg

Stefan Backa

Anders Eidenvall

Mats Åbom

Stevan Backa

Erik Kihlberg

In the present invention a controllable acoustic source () in connection with the process fluid () emits a signal () into the fluid (), consisting of a suspension of particles (), being volumes of gas, liquid or solid phase. The controllable acoustic signal () is allowed to interact, with the particles (), and the acoustic (pressure) signals () resulting from such an interaction is measured preferably via a sensor (). A spectrum is measured. The spectrum is used to predict properties, content and/or size of the particles () and/or used to control a process in which the process fluid () participates. The prediction is performed in the view of the control of the acoustic source (). The used acoustic signal has preferably a frequency below 20 kHz.

Active acoustic method for predicting properties of process fluids comprising solid particles or gas/liquid volumes based on their size distribution and concentration

An arrangement for a metal making process for detecting cracks along a strip of a metallic material moving in relation to the arrangement. The arrangement includes a coil arrangement fixedly arranged during crack inspection, having: a first winding portion extending in a first direction for inducing a first current in the first direction; a second winding portion extending in a second direction for inducing a second current in the second direction, the first direction and the second direction intersecting each other; a first receiver coil arranged to detect a magnetic field generated by the first current; and a second receiver coil arranged to detect a magnetic field generated by the second current, the magnetic field generated by the first current and the magnetic field generated by the second current providing a measure of whether a crack is present in the portion of the strip.

Arrangement for crack detection in metallic materials in a metal making process

A method of determining a crack depth of a crack in a metallic material including the steps: feeding a current with a first magnitude to a transmitter coil for generating a magnetic field in the metallic material; controlling the current such that it obtains a second magnitude when the magnetic field is estimated to have penetrated deeper than a deepest crack depth desired to be measured in the metallic material; detecting the magnetic field by means of a receiver coil; determining a first characteristic value of the signal in a first time range; determining a second characteristic value of the signal in a second time range after the first time range; and determining a possible presence of a crack and its crack depth based on the first characteristic value and the second characteristic value.

Method and arrangement for crack detection in a metallic material

An apparatus for estimating or supervising one or more internal mechanical properties of a metal alloy object with a known chemical composition based on the resistivity of the metal alloy object. The apparatus includes a device for measuring the resistivity of the metal alloy object, and a computation unit adapted to calculate the content of dissolved alloying elements in the metal alloy object based on the measured resistivity and the known chemical composition of the metal alloy, and based thereon to calculate at least one internal mechanical property of the metal alloy object.

Method and apparatus for estimating a mechanical property

A method and an apparatus for measuring the thickness of a metal layer. The metal layer has a resistivity (&#x3c1;) that differs from the resistivity (&#x3c1;) of the metal object. The apparatus includes a first device arranged to generate a magnetic field in close vicinity of the metal layer, and to generate a variation of the magnetic field so that a current is induced in the surface of the metal layer, a second device arranged to measure the changes of the magnetic field outside the metal layer due to the induced current during a time period that is longer than the time it takes for the current to propagate through the metal layer, and a computing unit to determine the thickness of the layer based on a mathematical relation between the thickness of the layer and the measured values of the changes of the magnetic field.

Method and apparatus for measuring the thickness of a metal layer provided on a metal object

In the present invention a refiner () of a mechanical pulping line is supplied with a controllable acoustic source (), arranged for emitting acoustic signals into the pulp fluid. The controllable acoustic signal is allowed to interact with the fibres in the pulp, and the acoustic (pressure) signals resulting from such an interaction is measured. At least one spectral component is measured. The measured spectral component is used to predict properties, content and/or size of the fibres. These properties may then be used to control the refiner () process. The used acoustic signal has preferably a wavelength that is large compared with a typical site of the particles.

Refiner control

Method and device for inductive measurement of physical parameters of an

Edge position determination of metallic materials by means of evaluation of the voltages which are induced in coils located at the edges of the material below the material and partially covered by the material as well as coils located inside of the first-mentioned coils in the transverse direction of the material, which latter coils are completely covered by the material in connection with a decaying magnetic field which is generated by the same coils.

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Västerås, Sweden

Lennart Thegel