Mettler-Toledo Gmbh

Mettler-Toledo Ag

Stefan Bühler

Daniel Reber

Jean-Christophe Emery

Michael Geiser

Hansruedi Künzi

Daniel Mock

Cyrill Bucher

Hans-Peter Von Arb

A balance () is a single unit with a weighing pan () enclosed in a weighing compartment (). A housing () adjoins the weighing compartment. The balance housing contains a weighing cell compartment () enclosing a weighing cell, an electronics compartment () containing electrical and electronic circuit elements, a thermoelectric heat pump module () and a heat flow controller (). The balance is equipped to determine a net heat flow (P) inside the housing in the direction from the weighing cell compartment to the electronics compartment. The heat flow controller uses the net heat flow as a control input to regulate the the thermoelectric heat pump module, arranged inside the housing. The control input is used to generate an active heat flow (P) with magnitude and direction for holding the net heat flow at a level equal to the rate of heat dissipation produced inside the weighing cell compartment.

Balance with active heat flow control

A method estimates the effect on the weighing result of a balance () that is caused by electrostatic charges on an object () received on a load receiver () thereof. A first predefined positive voltage (U) and a second predefined negative voltage (U) of equal magnitude are alternatingly applied to a first electrode () in the vicinity of the weighing object. The forces acting on a force-measuring cell () are measured and are registered as the first and second measurement results. The difference between the respective measurement results represents the magnitude of the influence that the electrostatic charges residing on the weighing object are having on the weighing result. The difference also represents an essentially proportional part of the force resulting from electrostatic charges on the weighing object which causes a change in the weighing result and is sent as a signal to a processor unit.

Method of estimating the electrostatic force on an object to be weighed by applying charges of opposite polarity to alternating electrodes and measuring the resultant forces

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Nänikon, Switzerland

Stefan Bühler