Device and method of measuring the gas-to-liquid ratio of the refrigerant of a refrigeration cycle
AssigneeDanfoss A/S
InventorsKumaran CHANDRAN, Vahid KHORSHIDI, Roozbeh IZADI-ZAMANABADI
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Abstract
The invention relates an apparatus (2) for measuring the ratio value of gas versus liquid in a gas-liquid of a refrigerant (6), comprising at least one control logic (3) and at least one capacitive sensing element (4) comprising at least two electrodes (7). The apparatus (2) is designed and arranged in a way that the fluid (6) is present between said two electrodes (7). The control logic (3) measures the capacitance of the capacitive sensing element (4) and derives a measurement signal to be outputted that is indicative of the ratio value of gas versus liquid in the fluid (6).
Claims15
Apparatus (2) for measuring the ratio value of gas versus liquid in a gas-liquid mixture fluid (6), preferably of a refrigerant (6), comprising at least one control logic (3) and at least one capacitive sensing element (4) comprising at least two electrodes (7), wherein the apparatus (2) is designed and arranged in a way that the fluid (6) is present between said two electrodes (7), characterised in that the control logic (3) measures the capacitance of the capacitive sensing element (4) and derives a measurement signal to be outputted that is indicative of the ratio value of gas versus liquid in the fluid (6).
Apparatus (2) according to any of the preceding claims, characterised in that said at least two electrodes (7) consist of the same material and/or are electrically isolated from the fluid to be measured.
Apparatus (2) according to any preceding claims, characterised in that the control logic calculates and outputs a ratio value of gas versus liquid, in particular based on prior obtained calibration data.
Apparatus (2) according to any of the preceding claims, characterised in that the control logic (3) outputs a warning signal in case a certain ratio value of gas versus liquid in the fluid (6) is exceeded and/or undercut, and/or the content of bubbles in a liquidous phase is exceeded and/or undercut and/or in case a certain content of droplets in a gaseous phase is exceeded and/or undercut.
Apparatus (2) according to any of the preceding claims, characterised in that the control logic (3) also calculates a water content value in the fluid and/or a pressure level in the fluid, based on the measured capacitance of the capacitive sensor element (4).
Refrigeration cycle (1) comprising a compressor (8), a condenser (9), a pressure drop inducing device (10) and an evaporator (11), further comprising an apparatus (2) according to any of the preceding claims.
Refrigeration cycle (1) according to claim 11, characterised in that said at least one capacitive sensing element (4) is arranged between the condenser (9) and the pressure drop inducing device (10) and/or between the evaporator (11) and the compressor (8) and/or between the compressor (8) and the condenser (9).
Method (20) for measuring the ratio value of gas versus liquid in a fluid (6), preferably of a refrigerant (6), using the capacitance measurement of at least one capacitive sensing element (4) that comprises at least two electrodes (7) that are designed and arranged in a way that the fluid to be measured (6) is present between said two electrodes (7), and calculating an output signal being indicative of the ratio value of gas versus liquid in a fluid (6), in particular of the amount of bubbles in the liquidous phase of the fluid (6) and/or of the amount of liquid droplets in the gaseous phase of the fluid (6), based on the measured capacitance of the at least one capacitive sensing element (4).
Dependencies are inferred from the claim text.