A device for measuring flow (F L, F G) of a fluid medium in a milk line containing a first fluid and a second fluid, wherein the first fluid is a gas and the second fluid is a liquid, the device comprising: a conduit configured to receive and transport the fluid medium through a measurement section, a first sensor device arranged in the measurement section, and configured to respond to at least one stimulus caused by the fluid medium and to register a first measure representing a first type of physical characteristic of the fluid medium flowing through the measurement section, a second sensor device arranged in the measurement section, the second sensor device being configured to respond to at least one stimulus caused by the fluid medium and to register a second measure representing a second type of physical characteristic of the fluid medium flowing through the measurement section, the second type of physical characteristic being different from the first type of physical characteristic, the second measure being independent from the first measure and the first and second measures (m1; m2) both being dependent on the flow (F G) of the first fluid and the flow (F L) of the second fluid in the fluid medium; and a processor configured to, based on the first and second measures (m1;m2), derive a flow (F G) of the first fluid and a flow (F L) of the second fluid in the fluid medium, characterized in that the device comprises at least one data storage including a first look-up table representative of a first characteristic flow pattern and containing a first collection of value pairs, each value pair representing a first value of the flow (F G) of the first fluid and a first value of the flow (F L) of the second fluid for a given combination of the first and second measures (m1;m2), and a second look-up table representative of a second characteristic flow pattern and containing a second collection of value pairs, each value pair representing a second value of the flow (F G) of the first fluid and a second value of the flow (F L) of the second fluid for a given combination of the first and second measures (m1;m2), the processor is configured to receive a series of first measures registered during a measurement interval,and based thereon, estimate a flow pattern of the fluid medium during said measurement interval, wherein the flow pattern describes how the first fluid and the second fluid are distributed in the measurement section over time derive the flow (F G) of the first fluid and the flow (F L) of the second fluid by using the first look-up table, if the flow pattern fulfills a first flow-pattern criterion; and derive the flow (F G) of the first fluid and the flow (F L) of the second fluid by using the second look-up table, if the flow pattern fulfills a second flow-pattern criterion. a conduit configured to receive and transport the fluid medium through a measurement section, a first sensor device arranged in the measurement section, and configured to respond to at least one stimulus caused by the fluid medium and to register a first measure representing a first type of physical characteristic of the fluid medium flowing through the measurement section, a second sensor device arranged in the measurement section, the second sensor device being configured to respond to at least one stimulus caused by the fluid medium and to register a second measure representing a second type of physical characteristic of the fluid medium flowing through the measurement section, the second type of physical characteristic being different from the first type of physical characteristic, the second measure being independent from the first measure and the first and second measures (m1; m2) both being dependent on the flow (F G) of the first fluid and the flow (F L) of the second fluid in the fluid medium; and a processor configured to, based on the first and second measures (m1;m2), derive a flow (F G) of the first fluid and a flow (F L) of the second fluid in the fluid medium, the device comprises at least one data storage including a first look-up table representative of a first characteristic flow pattern and containing a first collection of value pairs, each value pair representing a first value of the flow (F G) of the first fluid and a first value of the flow (F L) of the second fluid for a given combination of the first and second measures (m1;m2), and a second look-up table representative of a second characteristic flow pattern and containing a second collection of value pairs, each value pair representing a second value of the flow (F G) of the first fluid and a second value of the flow (F L) of the second fluid for a given combination of the first and second measures (m1;m2), the processor is configured to receive a series of first measures registered during a measurement interval,and based thereon, estimate a flow pattern of the fluid medium during said measurement interval, wherein the flow pattern describes how the first fluid and the second fluid are distributed in the measurement section over time derive the flow (F G) of the first fluid and the flow (F L) of the second fluid by using the first look-up table, if the flow pattern fulfills a first flow-pattern criterion; and derive the flow (F G) of the first fluid and the flow (F L) of the second fluid by using the second look-up table, if the flow pattern fulfills a second flow-pattern criterion.