System for measuring moisture content
AssigneeMotorola Process Control Inc.
InventorWalfred R. Raisanen
Life of this patent
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Abstract
A system for measuring moisture content in a porous material uses a microprocessor. The sample of material is placed on a load cell which provides an output to an analog-to-digital converter. The analog-to-digital converter provides a digital input for the microprocessor. The microprocessor is capable of providing an output indicative of the moisture content as a wet basis or a dry basis output. The system provides a highly accurate measurement of the moisture content while minimizing operator errors.
Claims11
A gravimetric moisture measuring system, comprising:
- means for weighing a material whose moisture content is to be determined, the means for weighing producing an output electrical signal representative of weight of the material;
- an analog-to-digital converter coupled to the means for weighing to provide a digital output representative of the weight of the material;
- a digital data processor for processing the digital output and for determining change of the digital output to allow the digital data processor to provide a continuously updated output representative of the moisture content of the material, the digital data processor including a microprocessor, a random access memory, and a read only memory;
- means for displaying the output of the digital data processor;
- and means for heating the material to cause a change in the moisture content of the material the means for heating being controlled by the digital data processor.
A thermal gravimetric system for measuring moisture content of a porous material, comprising:
- means for weighing the material, the means for weighing providing an output corresponding to weight of the material;
- means for heating the material for a period of time to dry out moisture contained therein;
- means to convert the output of the means for weighing from an analog signal to digital data;
- means for processing the digital data in a manner to determine rate of change in the means for processing controlling the period of time the means for heating provides heat to the means to convert and having a plurality of reference voltages coupled to the multiplexer so that the reference voltages can be used for calibration and diagnostic purposes.
A thermal gravimetric system for measuring moisture content of a porous material, comprising:
- a scale for measuring the material and for providing an electrical output corresponding to weight of the material;
- a low bandwidth amplifier coupled to the scale to amplify the electrical output;
- an analog-to-digital converter coupled to the amplifier for converting the amplified electrical output to a digital signal;
- a microprocessor for processing the digital signal to provide outputs indicative of moisture content of the material;
- a read only memory coupled to the microprocessor;
- a digital data bus for coupling data to the microprocessor;
- a peripheral interface adaptor coupled to the data bus for coupling a portion of data from the analog-to-digital converter to the microprocessor;
- an alpha-numeric display coupled to the peripheral interface adaptor to display outputs of the microprocessor;
- and a heating element to heat the material to dry out moisture contained therein, the heating element being coupled to the digital data bus so that the microprocessor can control how long a period of time the heating element provides heat.
Dependencies are inferred from the claim text.