Did You Know...
...that the x-ray was discovered purely by accident? When German physicist Wilhelm Konrad von Roentgen was experimenting with cathode rays in 1895, he put an activated Crookes tube in a book and went out to lunch. When he returned, he discovered that a key that had also been placed in the book showed up as an image on the developed film!
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| Number | Title | Issue Date |
| 7278186 | Ultra low frequency moisture sensor An apparatus for measuring a moisture content value within a volume. A frequency generator generates at least one source signal at frequencies of no more than about one kilohertz. Probes are disposed with surfaces in physical contact with the volume, where no direct... | 10/09/2007 |
| 7275415 | Particulate-based flow sensor A fluid conveyance apparatus having more than one particulate matter sensing probe situated at two or more locations on the apparatus. Signals from the probes from at least two locations may indicate particulate matter flowing within a fluid through the conveyance a... | 10/02/2007 |
| 7205779 | Apparatus and method for monitoring and determining the moisture content in elastomer materials An apparatus and method for determining and monitoring the moisture content of an elastomer material used as a closure or stopper for containers holding lyophilized pharmaceutical products, comprising a parallel capacitance circuit formed by supplying a source of AC... | 04/17/2007 |
| 7145350 | Process and a circuit arrangement for evaluating a measuring capacitance A process is disclosed for evaluating a measuring device comprising a capacitor (CM), with stages for charging the capacitor (CM) over an initial charging period (tk1, tk2) and for determining the capacitance charge as an initial measured value (tml). ... | 12/05/2006 |
| 7098618 | Rain detection system and method of controlling the same A rain detection system generates an operation signal for operating a wiper system on a window based on a detected window condition. The rain detection system includes a detection mechanism for intermittently detecting an amount of liquid on the window, a calculatio... | 08/29/2006 |
| 7084644 | Circuit arrangement for capacitive humidity measurement and method for operating the same A circuit arrangement for capacitive humidity measurement that includes a capacitive element to be measured, a plurality of switch elements, a charge storage element and a control unit electrically connected to the capacitive element, the plurality of switch element... | 08/01/2006 |
| 7030631 | Method and apparatus for monitoring and determining the moisture content of a substance in a container A method and apparatus for monitoring and determining the moisture content of a sample substance inside a closed container. The apparatus includes a parallel capacitance circuit formed by a source of AC voltage supplied to a reference container and a sample containe... | 04/18/2006 |
| 6945287 | Columnar seal for particle processing system A backflow blocker prevents backflow of gas to a lower pressure first stage of a system for processing particles from a downstream higher pressure second stage of the system. The blocker comprises an upright duct connecting the first stage to the second stage. The d... | 09/20/2005 |
| 6917206 | Multiple frequency grain moisture sensor for combines A grain moisture sensor having a sensor cell that includes a driven plate, a sense plate proximate to and substantially parallel with the driven plate for capacitive measurement across a spacing between the driven plate and the sense plate, and a fill plate adjacent... | 07/12/2005 |
| 6806717 | Spacing compensating electrostatic voltmeter An electrostatic type voltmeter for measuring the potential on a surface, the voltmeter including a probe; a support for supporting the probe in spaced relationship with the surface, the probe having a plurality of spacing element sites thereon for measuring a dista... | 10/19/2004 |
| 6570395 | Portable grain moisture meter A portable grain moisture measurement device has an automatic grain moisture measurement actuation system whenever the compaction of the grain within a test cell of the device is at a preset value and upon such automatic actuation a visual display is acti... | 05/27/2003 |
| 6462562 | Differential capacitance probe for process control involving aqueous dielectric fluids A differential capacitance probe device for process control involving aqueous dielectric fluids is disclosed. The device contains a pair of matched capacitor probes configured in parallel, one immersed in a sealed container of reference fluid, and the oth... | 10/08/2002 |
| 6414497 | Paving material analyzer system and method A paving material analyzer system is disclosed that uses paving material impedance to determine paving material density. The invention also includes a method for analyzing paving material, in particular, determining paving material density. The paving mat... | 07/02/2002 |
| 6392416 | Electrode integrity checking Impedance between potential sensing electrodes of a high impedance meter is measured by applying a ramp waveform through a capacitor coupled to one of the electrodes to generate a substantially constant current, a measure of impedance being obtained by co... | 05/21/2002 |
| 6373263 | Differential windshield capacitive rain sensor A capacitive sensor for detecting raindrops on the external surface of a vehicular windshield, relying for its operation on the compensation of the capacitive signals which are due to variation of the dielectric constant of the windshield's glass with tem... | 04/16/2002 |
| 6351132 | Miscible liquid capacitive sensing system A capacitive sensor is employed to measure the dielectric constant of miscible liquids, and thereby determine the relative concentration of the two liquids. Further, a feedback circuit may be provided to change the operation of the system in accordance wi... | 02/26/2002 |
| 6346819 | Method and device for determining proportions of solid matter in a test material The invention relates to a method and a device for determining proportions of solid matter in a test material. In order to reliably and easily determine proportions of solid matter in a test material, even in the case of transparent matter or matter of a ... | 02/12/2002 |
| 6275046 | Cotton moisture meter The method and structure of a moisture measuring device that creates an electric field and then determines a moisture content of a specimen based on the effect the moisture of the specimen has on the electric field.... | 08/14/2001 |
| 6269693 | Capacitive sensor for a fluid forming a dielectric in a capacitor A capacitive sensor for measuring a characteristic of a fluid or a filling depth of a liquid in a container is constructed of a printed circuit board that is either flexible or has stiff and flexible sections along its length. Metal coatings forming capac... | 08/07/2001 |
| 6193424 | Apparatus and method for automatically diluting concentrated replenishers and liquid level control apparatus Provided is a concentrated replenisher automatic diluting apparatus and method that can easily and accurately dilute concentrated replenishers and that can set the amount of agents included in the replenishers supplied to processing tanks to ideal values ... | 02/27/2001 |
| 6138508 | Digital liquid level sensing apparatus A digital liquid level sensing apparatus for detecting variations in the dielectric of a substance being sensed. The apparatus includes a capacitive element array including a plurality of individual (i.e., segmented) input plates positioned along an axis ... | 10/31/2000 |
| 6072309 | Paper stock zeta potential measurement and control System and method for producing paper that employ an apparatus for measuring electrical characteristics of a fibrous composition. The apparatus comprises a plurality of conductivity (or resistance) detectors each comprising a sensor that is sensitive to t... | 06/06/2000 |
| 5955887 | Impedance type ice detector An ice detector includes a pair of electrodes connected by a pair of leads to a control unit which measures the total impedance between leads to thereby sense and detect the presence of ice and other contaminants formed on top thereof utilizing a comparat... | 09/21/1999 |
| 5898309 | Method for determining specific material characteristics A method and apparatus for determining specific material characteristics of plastic materials in which the plastic material is disposed between electrodes of a capacitive sensor and the impedance is measured and compared to a reference value, preferably s... | 04/27/1999 |
| 5891306 | Electromagnetic field perturbation sensor and methods for measuring water content in sheetmaking systems A system and method of producing a paper product from a wetstock solution using a sensor for sensing resistive impedance changes of the wetstock on the support web of the system. The resistive impedance changes are used to measure physical characteristics... | 04/06/1999 |
| 5642098 | Capacitive oil water emulsion sensor system A sensor system is operable for detecting the presence of water in an oil emulsion inside the lower gear unit of a marine engine, and for providing an alarm signal when the presence of water is detected within the gear unit. The sensor system includes a r... | 06/24/1997 |
| 5629629 | Circuit arrangement for determining differences in capacitance In a circuit arrangement for determining differences in capacitance, two capacitors (1,2) are alternately connected to an integrator with differential amplifier (3) whose input current is positive (+I) when the first capacitor (1) is integrated or negativ... | 05/13/1997 |
| 5450015 | Apparatus for measuring impedance to determine a property of a material An impedance measurement system including a series circuit having a reference impedance leg and a measurement leg, the measurement leg including first and second spaced apart electrodes defining a region for receiving a sample of material to be tested; an... | 09/12/1995 |
| 5423214 | Variable fluid and tilt level sensing probe system Digital tilt level sensing probe system comprising a set of multiple capacitor elements in a fluid container arranged along an axis of measurement where each multiple capacitor element represents a discrete level increment in dielectric material fluid to ... | 06/13/1995 |
| 5138880 | Digital level sensing probe system Digital level sensing probe system including digital probe constructed of two (2) concentric cylinders, forming a set of discrete, cylindrical capacitors that use the substance whose level is to be measured as a dielectric material. The set of capacitors ... | 08/18/1992 |
| 4845421 | Method and apparatus for measuring the moisture content of a substance The moisture content of a substance (1) on a moving belt (2) is measured as a function of dielectric constant. Two pairs of electrodes (4), (5) are positioned adjacent the belt, an inner pair of electrodes (4) and an outer pair (5), an A.C. potential is a... | 07/04/1989 |
| 4831325 | Capacitance measuring circuit A variable capacitor, which may be a humidity sensitive capacitor, and a fixed reference capacitor are connected at a node. The node is clamped at a reference potential during a first phase of a two phase measuring cycle as the variable capacitor is charg... | 05/16/1989 |
| 4806847 | Dielectric liquid level sensor and method A sensor for sensing the level of oil or transmission fluid under both normal and extreme temperature conditions. The only active components of the sensor have input and leakage currents substantially lower than those of diodes and current sources under h... | 02/21/1989 |
| 4736156 | Apparatus for on-line determination of dielectric constant An improved apparatus for the "on-line" measurement of the dielectric constant or percent moisture of a material such as tobacco moving within the walls of a pipe or chute is disclosed. A differential capacitive technique is used for the measurement. The ... | 04/05/1988 |
| 4568875 | Moisture corrected denier measurement Measurements of yarn denier using capacitance transducers are automatically corrected for moisture. Samples of the yarn to be run are tested at different moisture levels at different frequencies in each of two capacitance transducers. The difference in th... | 02/04/1986 |
| 4562430 | Position detection device for magnetic bearing A device comprising a capacitive transducer comprised of a fixed member comprising first and second axially separated equal diameter metallic electrode rings and a movable member comprised of a thin walled metallic cylinder separated from the fixed member... | 12/31/1985 |
| 4547725 | Method and apparatus for the continuous determination of moisture pourable food The invention addresses a new process for determination of characteristic quantities, particularly the moisture content, of a pourable food moving along a product line, particularly grain and its processing products. In this process the good is passed thr... | 10/15/1985 |
| 4517547 | Water-in-fuel sensor circuit and method A reference capacitor is coupled in parallel with a capacitor of which the size thereof is variable and an oscillator is used to alternately charge and discharge both capacitors between first and second voltage levels. The absolute magnitude of the curren... | 05/14/1985 |
| 4468610 | Radio frequency apparatus for measuring moisture content of materials as a function of dielectric constant Apparatus for measuring moisture content of gypsum board and like products as a function of dielectric constant comprising an rf signal source, an antenna disposed for rf field coupling to a test material, first and second reference inpedances, and a cont... | 08/28/1984 |
| 4429272 | Apparatus for indicating dielectric constant An apparatus for providing an indication of a change in the dielectric constant of a fluid comprises a pair of electrodes at least one of which in use is surrounded by the fluid, an oscillator operable to charge and discharge the capacitors formed by the ... | 01/31/1984 |
