A DENSITY AND VISCOSITY SENSOR

摘要

A density and viscosity sensor (1) for measuring density and viscosity of fluid F, the sensor (1) comprising: - a resonating element (3, 3A, 3B, 3C, 3D, 3E, 3F, 3G) arranged to be immersed in the fluid F, - an actuating/detecting element (4, 4A, 4B) coupled to the resonating element, - a connector (7) for coupling to the actuating/detecting element (4, 4A, 4B), - a housing (2) defining a chamber (8A) isolated from the fluid F, the housing (2) comprising an area of reduced thickness defining a membrane (9) separating the chamber (8A) from the fluid F, the membrane (9) having a thickness enabling transfer of mechanical vibration between the actuating/detecting element (4, 4A, 4B) and the resonating element (3, 3A, 3B, 3C, 3D, 3E, 3F, 3G), - the actuating/detecting element (4, 4A, 4B) is positioned within the chamber so as to be isolated from the fluid F and mechanically coupled to the membrane (9), - the resonating element (3, 3A, 3B, 3C, 3D, 3E, 3F, 3G) arranged to be immersed in the fluid F is mechanically coupled to the membrane (9), wherein the resonating element (3, 3A, 3B, 3C1 3D, 3E, 3F, 3G) has a shape defining a first resonance mode and a second resonance mode characterized by different resonant frequencies F<SUB>1</SUB>,F<SUB>2</SUB> and different quality factors Q<SUB>1</SUB> ,Q<SUB>2</SUB>, the first resonance mode moving a volume of fluid, the second mode shearing a surrounding fluid.