Measuring instrument and method for determining the alcohol content of a mixture
First Claim
1. A measuring instrument for determining the alcohol content of a mixture, comprising;
- a measuring configuration through which a mixture flows, said measuring configuration including a casing with a wall, part of said wall forming a first electrode, and a sensor element around which the mixture flows, said sensor element forming a second electrode, said first and second electrodes forming a capacitor and the mixture flowing between said first and second electrodes forming a dielectric of said capacitor, said capacitor having a capacitance and the dielectric having a conductance, and wherein an alcohol content of the mixture is to be determined from a dielectric constant of the mixture determined from the capacitance and from the conductance;
a measuring circuit having an oscillator with a first input connected to said measuring configuration and a second input;
a control circuit connected to said second input for generating a given number of control voltages and transmitting the control voltages to said second input of said oscillator; and
means for measuring an oscillator frequency for each of the control voltages.
1 Assignment
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Accused Products
Abstract
A measuring instrument has a measuring configuration and a measuring circuit. The measuring circuit determines the capacitance of a capacitor and the conductance of the measuring configuration, which is formed of a casing and a sensor element around which a mixture flows. The alcohol content of the mixture is determined therefrom. The measuring circuit has an oscillator and a control circuit connected upstream thereof. The measuring configuration, which is represented by the capacitor and the conductance, is a part of the oscillator, which oscillates within a measuring cycle at three different oscillator frequencies which are set by three different control voltages of the control circuit, and evaluated in a microcontroller. Component tolerances which influence the oscillator frequencies can thus be taken into account.
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Citations
10 Claims
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1. A measuring instrument for determining the alcohol content of a mixture, comprising;
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a measuring configuration through which a mixture flows, said measuring configuration including a casing with a wall, part of said wall forming a first electrode, and a sensor element around which the mixture flows, said sensor element forming a second electrode, said first and second electrodes forming a capacitor and the mixture flowing between said first and second electrodes forming a dielectric of said capacitor, said capacitor having a capacitance and the dielectric having a conductance, and wherein an alcohol content of the mixture is to be determined from a dielectric constant of the mixture determined from the capacitance and from the conductance; a measuring circuit having an oscillator with a first input connected to said measuring configuration and a second input; a control circuit connected to said second input for generating a given number of control voltages and transmitting the control voltages to said second input of said oscillator; and means for measuring an oscillator frequency for each of the control voltages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining the alcohol content of a mixture with a measuring instrument including:
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a measuring configuration through which a mixture flows, the measuring configuration forming a capacitor having a capacitance and the mixture flowing through the capacitor having a conductance and the alcohol content of the mixture is to be determined from the capacitance and the conductance, the measuring configuration including a casing with a wall, part of the wall forming a first electrode, and a sensor element around which the mixture flows, the sensor element forming a second electrode; and
a measuring circuit having an oscillator with a first input connected to the measuring configuration and a second input receiving a given number of control voltages, whereby the capacitance of the capacitor is determined from an oscillator frequency, and means for measuring the oscillator frequency for each of the control voltages;the method which comprises; generating the control voltages in a control circuit for supplying the control voltages to the oscillator, and generating a plurality of the oscillator frequencies by varying the control voltage for determining a plurality of parameters of the measuring configuration from the oscillator frequencies. - View Dependent Claims (10)
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Specification