LIQUID LEVEL VARIATION DIFFERENTIAL SENSOR Russian patent published in 2011 - IPC G01F23/16 

FIELD: physics.

SUBSTANCE: liquid level variation differential sensor consists of an airtight housing 1, a membrane unit 2, an electronics module 3 mounted inside the airtight housing 1 over the membrane unit 2, a controlled valve 4 and a compensation tube 5. The membrane unit 2 is filled with dielectric liquid and consists of two oil-resistant membranes 6 and 7 placed one over the other, two dielectric supporting plates 9 and 10 with electrodes 11, rigidly attached on the edges of the housing 8 of the membrane unit 2, lying between and parallel to membranes 6 and 7 with a gap from each other, and rigidly attached on the edges to the housing 1 of an electroconductive measurement membrane 12, placed between dielectric supporting plates 9 and 10. Electrodes 11 face the electroconductive measurement membrane 12. The top oil-resistant membrane 6 is placed with spacing from the cover 13 of the membrane unit 2 with formation of a compensation cavity 14. The bottom oil-resistant membrane 7 is the bottom of the housing 8 of the membrane unit 2. The controlled valve 4 and the compensation tube 5 are connected to the compensation cavity 14. The controlled valve 4 is connected to the control unit of valve 15 and is linked to liquid outside the housing. The electronics module 3 is in form of a differential capacitance transducer 16, inputs of which are connected to electrodes 11, and the output - to an analogue-to-digital transducer 17, connected to the control unit of valve 15, connected to the controlled valve 4. The electronics module 3 is connected to the control and detection system 18. The electroconductive measurement membrane 12 has low rigidity since it is made from elastic material with a small thickness, which ensures high sensitivity of the sensor.

EFFECT: such a design of the sensor increases accuracy and reliability of measuring variations of the level of a liquid.

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