Abstract: A transducer for measuring the relative velocity of movement of a body in a liquid or gaseous medium employs no reciprocating parts and functions by sensing the force applied to a diaphragm (6) die to its movement through the medium or the movement of the medium towards the diaphragm. The speed transducer makes use of a Hall effect solid state device (7) that produces an output when a magnetic field is applied to either of its surfaces. The level of the output voltage is proportional to the velocity of movement in the positive direction, i.e. when the force acts on diaphragm (6) in (FIG. 1). Since the transducer takes into account differential forces, an unwanted common force acting on both diaphragms simultaneously will have no effect on the measured speed. The tubular body (1) in which the Hall effect device is located may be made from any non-magnetic material suitable for the environment in which the transducer will be used.

Abstract: A transducer for measuring the relative velocity of movement of a body in a liquid or gaseous medium employs no reciprocating parts and functions by sensing the force applied to a diaphragm (6) die to its movement through the medium or the movement of the medium towards the diaphragm. The speed transducer makes use of a Hall effect solid state device (7) that produces an output voltage when a magnetic field is applied to either of its surfaces. The level of the output voltage is proportional to the velocity of movement in the positive direction, i.e. when the force acts on diaphragm (6) in (FIG. 1). Since the transducer takes into account differential forces, an unwanted common force acting on both diaphragms simultaneously will have no effect on the measured speed. The tubular body (1) in which the Hall effect device is located may be made from any non-magnetic material suitable for the environment in which the transducer will be used.