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A liquid level detector of the type in which a magnetostrictive wire extends through the liquid level measurement range and is captured in a tensioned vertical orientation within a stainless steel tube. Liquid level is measured as a function of the time required for a torsional disturbance imparted

A liquid level detector of the type in which a magnetostrictive wire extends through the liquid level measurement range and is captured in a tensioned vertical orientation within a stainless steel tube. Liquid level is measured as a function of the time required for a torsional disturbance imparted the wire near the top to travel along the wire to a magnet which is contained within a liquid level float which slides up and down along the tube. The torsional disturbances imparted to the wire by means of a piezoelectric crystal to which the wire is easily clamped. Accuracy is enhanced by measuring liquid level as a function of the elapsed time between an actuation signal and the first zero crossing of the voltage which is induced as the torsional strain passes through the area of influence of the sliding magnet.

대표청구항 ▼

In a position transducer having a housing, a magnetostrictive wire disposed within the housing and mechanically anchored at opposite head and foot ends to define a position measurement range therebetween, a pulse generator for generating an actuation signal, an actuator connected to said pulse gener

In a position transducer having a housing, a magnetostrictive wire disposed within the housing and mechanically anchored at opposite head and foot ends to define a position measurement range therebetween, a pulse generator for generating an actuation signal, an actuator connected to said pulse generator for imparting a torsional strain to the head end of the wire in response to said actuation signal, and a magnet disposed slidably mounted on the housing for linear displacement along said wire within said position measurement range thereby to produce an induced voltage in the wire upon the arrival of said torsional strain by propagation along said wire at the position of said magnet, the improvement comprising: a circuit for producing a signal which is time positioned relative to the application of said actuation signal to the actuator according to the linear position of the magnet along the wire, said circuit including means responsive to said actuation signal to initiate a position measurement interval, and means responsive to said induced voltage to terminate the interval upon a preselected zero crossing of said induced voltage.