Abb Research Ltd.

Abb Schweiz Ag

Georg Mueller

Klaus Bohnert

Andreas Frank

Xun Gu

Detlef Pape

Thomas Alfred Paul

Axel Kramer

A method for operating an ore comminution circuit is provided. The method includes obtaining at least one sensor signal related to an ore feed to the comminution circuit; determining a first ore grindability parameter of the ore feed from the at least one sensor signal, using a model; determining a second ore grindability parameter using parameters of the comminution circuit and/or of at least one comminution device in the comminution circuit; and updating the model with the second ore grindability parameter and the at least one sensor signal.

Method for operating a comminution circuit and respective comminution circuit

A fiber-optic current sensor uses a highly-birefringent spun fiber as sensing fiber. The light is fed through a retarder, which is a detuned quarter-wave or half-wave retarder. It is shown that such detuning can be used to compensate for temperature dependencies of the sensing head.

Fiber-optic current sensor with spun fiber and temperature compensation

In a fiber-optic current sensor, a 22.5&#xb0; Faraday rotator, which is part of the sensing fiber coil, determines the working point of the sensor. The coil is operated with substantially linearly polarized light or incoherent substantially left and right circularly polarized light waves. In one arrangement, a polarization beam splitter generates two optical signals that vary in anti-phase with changing current. A signal processor determines the current from the two anti-phase signals. Appropriately detuned and oriented fiber-optic half-wave or quarter-wave retarders before the fiber coil are used to reduce or cancel the adverse effects of temperature and bend-induced birefringence on the measurement signal. Moreover, the temperature may be derived from the difference in the bias of the anti-phase signals and may be used to cancel temperature effects in the signal processor.

Temperature compensated fiber-optic current sensor

Growing community of inventors

Glattpark, Switzerland

Georg Mueller