Apparatus and method for measurement of moisture concentration in granular materials
AssigneeJames Instruments Inc.
InventorJerald G. Assenheim
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Abstract
The measurement of moisture content in granular materials is ordinarily a difficult measurement to make. The invention of this application sets forth a new method and apparatus for measuring moisture content in a wide variety of materials by means of application of an apparatus that makes measurement of moisture content independent of density of the material measured, and thereby unaffected by ambient conditions. The apparatus also allows the practitioner of this invention to readily and accurately measure moisture content.
Claims11
A device for the measurement of moisture in a granular material using high frequency waves, comprising the following:
- a. A resonator, the field produced by which interacts with the material to be measured,
- b. an electromagnetic field directed to pass through the material to be measured,
- c. a square wave generator cooperatively connected to a triangle wave generator, which in turn emits waves which are generated by a high frequency generator,
- d. said high frequency generator emitting waves in the range of about 0.5 to about 20 gigahertz,
- e. means for determining the natural frequency of the resonator and frequency of the resonator in conjunction with the material being tested for moisture content,
- f. a high frequency diode for measuring the amplitude of voltage output from the resonator with and without material within it, and
- g. detection means for measuring the frequency shift and height of the peak voltage output of the resonator coupled to with the material being tested.
The method of measuring moisture content in granular materials using microwaves (high frequency waves) comprising the steps of:
- a. contacting the material wherein moisture is to be measured with a field produced by a resonator having a natural frequency and said resonator being cooperatively connected to a high frequency generator wherein said high frequency generator produces a frequency which is swept back and forth in a linear manner;
- b. said high frequency wave forms being further modulated by a triangle wave generator which sweeps the frequency;
- c. said output of said high frequency generator being within the range from about 0.5 to about 20 gigahertz, and wherein said wave forms are modulated to scan back and forth through a pre-determined range of frequency defined by the range of frequency for the moisture to be measured,
- d. measuring the height of the voltage peaks at resonance with the scanning frequency along wit the time period between the peaks obtained with increasing frequency, and the peaks obtained as the frequency is decreased, and
- e. determining the parameters of the complex dielectric constant for the material and thereby determining the moisture content of the material utilizing the voltage at resonant frequency.
Dependencies are inferred from the claim text.