| 摘要 |
A level sensor system for liquids and liquid slurries utilizes a capacitive probe which extends longitudinally into a liquid or liquid slurry containing vessel, and which may contain inner and outer sensors spaced from each other in an assembly with a flow control screen at its lower end to permit egress of liquid and exclusion of the solid slurry material, thereby enabling both liquid and slurry level to be determined. The capacitance presented by each sensor is converted into a digital output in repetitive cycles having a reference phase, where a reference voltage is generated by charging a reference capacitor while a counter is registering counts and until a pre-determined count is reached, and in a computing phase while counts are accumulated until the capacitance presented by the probe charges to a voltage equal to the reference voltage. The counts registered in the counter may be converted into level units and displayed or the difference between the liquid and slurry levels may be used to control a fluid system, as in the de-watering of waste, ion exchange resins and other waste filter media and sludges used in decontamination, water treatment in nuclear power plants.
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