A device for determining a physical quantity of a liquid flowing in a pipe

Apparatus for determining a physical value of a liquid flowing in a pipe, without contact with said liquid, said device comprising: - a sensor (3) of said physical quantity; - A connector (2) to insert into said pipe and comprising: - an internal passage (13) extending between two apertures (11, 12), - a flexible membrane (6) for a pressure sensor, forming a wall of said passage internal (13); and - fastening means (27, 62) of said sensor (3) on said connector (2); characterized in that said sensor is a temperature sensor (3) attached to said connector (2) with the sensitive part of said sensor (3) turned towards said membrane (6).