Transducer mounted between two spaced-apart interior surfaces of a cavity in the wall of a flow tube

摘要

An ultrasonic flow meter comprises a cavity disposed in the wall of a flow tube. This cavity is preferably elongated along a direction perpendicular to a flow axis and has a flat interior surface portion proximal an interior surface of a wall of the flow tube. A piezoelectric transducer has a surface bonded to the flat interior surface portion of the cavity so as to transmit and receive acoustic signals through a thin window in the wall of the flow tube. An encapsulant, which may be combined with other elements, such as a mechanical strengthening piece, bonds the second side of the piezoelectric wafer to a second surface of the cavity. In a particular preferred embodiment, the cavity may be a dovetailed groove cut into a wall of the flow tube.

主权项

1. An ultrasonic flow meter comprising a flow tube having a flow axis along which fluid flows when the meter is operating, the flow tube having a wall comprising an interior surface proximal the flow axis and an exterior surface distal therefrom, the flow meter further comprising:
a cavity disposed in the wall, the cavity not penetrating the interior surface thereof, the cavity elongated along a direction perpendicular to the flow axis and spaced apart therefrom, the cavity having a flat interior surface portion proximal the interior surface of the flow tube and a second interior surface portion distal therefrom; a piezoelectric transducer wafer having a first of two flat surfaces bonded rigidly to the flat interior surface portion of the cavity; and an encapsulant bonding the second flat surface of the transducer wafer to the second interior surface portion of the cavity.