Device and method of measuring the water content in the refrigerant of a refrigeration cycle
AssigneeDanfoss A/S
InventorsKumaran CHANDRAN, Vahid KHORSHIDI, Ali FOULLADPOUR
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Abstract
The invention relates to an apparatus (2) for measuring the water content of a refrigerant (6). The apparatus (2) comprises at least one control logic (3) and at least one capacitive sensing element (4) that comprises at least two electrodes (7), wherein the apparatus (2) is designed and arranged in a way that the refrigerant (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 water content. The capacitive sensor element (4) is designed and arranged as a direct current-decoupled device.
Claims13
Apparatus (2) for measuring the water content of a fluid (6), in particular 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), wherein 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 water content, characterised in that the capacitive sensor element (4) is designed and arranged as a direct current-decoupled device.
Apparatus (2) according to any of the preceding claims, characterised in that it is designed and arranged in a way to measure the water content of a fluid (6) with a dielectric constant of less than 70, preferably of less than 60, even more preferred of less than 50.
Apparatus (2) according to any of the preceding claims, characterised in that the control logic (3) generates a water content signal, in particular a PPM value, preferably using prior 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 water content level is exceeded and/or outputs an estimated remaining time until a certain water content level is prone to be reached or exceeded.
Apparatus (2) according to any of the preceding claims, characterised in that the control logic (3) also calculates a ratio value of gas versus liquid in a gas-liquid mixture fluid (6) and/or a value of bubble content in the fluid and/or a value of bubble content in the fluid (6) and/or a value of droplet content in the fluid (6), based on the 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.
Method (20) for measuring the water content of a fluid (6), in particular of a refrigerant (6), using the capacitance measurement of at least one capacitive sensing element (4) that comprises at least two electrodes (7), where the fluid (6) to be measured passes through the at least one capacitive sensing element (4) between the at least two electrodes (7) of the capacitive sensing element (4), and calculating an output signal being indicative of the water content in the fluid (6) based on the measured capacitance of the at least one capacitive sensing element (4), characterised in that the at least one capacitive sensing element (4) is designed and arranged as a direct current-decoupled device.
Dependencies are inferred from the claim text.