Abstract: A position detector includes an outer tube of having a magnetostrictive wire disposed therein. An electric circuit is mounted completely within the outer tube and is electrically connected to a pickup coupled to the magnetostrictive wire. A multi-pin connector is mounted at one end of the outer tube for coupling conductors extending from the circuit in the outer tube to external conductors. In an alternative embodiment, the position detector includes a threaded adapter threadingly mountable within an end wall of a pressurized fluid operated cylinder. Conductors extend from the circuit in the outer tube through the adapter to an external connector.

Abstract: A liquid level detection apparatus includes an outer tube of substantially constant diameter. A magnetostrictive wire is supported within the outer tube. An electrical circuit is mounted within the outer tube and is electrically connected to a pickup coupled to the magnetostrictive wire.

Abstract: A liquid level detection apparatus has an outer semi-rigid, flexible tube closely surrounding an inner, non-permeable tube containing a magnetostrictive wire. The outer tube prevents collapse of the inner tube during bending and flexing of the inner tube to enable the inner tube to be bent or coiled during storage, shipping, and installation.

Abstract: A magnetostrictive waveguide position measuring apparatus includes a waveguide extending between opposed anchored ends. A magnet is displaceable along the waveguide and generates torsional strain in the waveguide in response to an electrical excitation signal transmitted along the waveguide. A piezoceramic element sensor is coupled to the waveguide to sense the torsional strain signal on the waveguide. A signal processor determines the relative elapsed time between the excitation signal and the output signal of the piezoceramic element to determine the position of the magnet along the waveguide. The sensor is coupled to the waveguide by a low resonance coupling medium.

Abstract: A magnetostrictive waveguide position measuring apparatus includes a waveguide extending between opposed anchored ends. A magnet is displaceable along the waveguide and generates torsional strain in the waveguide in response to an electrical excitation signal transmitted along the waveguide. A piezoelectric film element is coupled to the waveguide to sense the torsional strain signal on the waveguide. A signal processor determines the relative elapsed time between the excitation signal and the output signal of the piezoelectric film element to determine the position of the magnet along the waveguide. The piezoelectric film element is coupled to the waveguide along an axis transverse to the axis of stretch of the element. Alternately, a differential piezoelectric film element formed of two piezoelectric elements contacts a waveguide, with the two elements connected in differential parallel or series configuration and in or out of phase to double the output current or the output voltage.

Abstract: The present application discloses a magnetostrictive linear displacement detector with an axial coil torsional strain transducer. The displacement detector includes a magnetostrictive wire, a return wire and a magnet disposed for displacement along the magnetostrictive wire. A torsional strain sensor at the head end generates an electrical indication of the torsional strain within the magnetostrictive wire induced by passage of an electrical excitation by the position of the magnet. The torsional strain sensor includes two serially connected coils wound in opposite directions. The total length is short compared with the rate of electrical propagation within the magnetostrictive wire and long compared with the rate of torsional strain propagation within the magnetostrictive wire. The induced current within the two coils from electrical excitation of the magnetostrictive wire substantially cancel out because generally the whole sensor is excited simultaneously.

Abstract: In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot end termination as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made by measuring the wire resistance and calculating a compensation from the resistance. The probe is excited by an electrical pulse having a known current. The voltage across the wire is measured at a time when the current has stabilized to a precise value, and resistance is determined from the current and voltage.

Abstract: In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made based on the property of the total propagation time along the wire length being a unique function of temperature and calibrating the probe at different temperatures to yield either equations or look up tables of true positions as functions of the total propagation time and the position detection parameter. By mapping wire characteristics at a plurality of magnet positions and temperatures to construct look up tables, wire nonlinearities as well as thermal effects can be compensated for.

Abstract: A position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet movable along the probe uses the sonic pulse propagation time from the magnet to the head as one parameter and the time from the magnet to the foot and reflected back to the head as another parameter for determining the magnet position. The sum of the propagation times is a constant which is used as a reference value. Upon receipt of the first two pulses the propagation times are summed and compared to the reference value, and the data is accepted if the sum is within a prescribed window around the reference value. When noise occurs, it creates a false measure of propagation time so that the sum of the propagation times is no longer equal to the reference value and the data is rejected.

Abstract: The present invention is a combined magnetostrictive linear displacement detector and plural location temperature detector. The combined apparatus produces a composite signal for transmission on a 2 wire transmission line. The resistances of the temperature sensitive resistors as well as two reference resistors are measured in a predetermined sequence. The linear displacement is measured by the length of time required for a torsional strain to travel along the magnetostrictive wire to the position of the magnet. A pulse generator generates a predetermined number of pulses for each resistance measurement having pulse period corresponding to the measured resistance, with the minimum such pulse period preferably being greater than twice the maximum time required for a torsional strain to propagate the length of the magnetostrictive wire. An electrical signal is supplied to the transmission line when either said pulse generator generates a pulse or the induced electrical signal is detected.

Abstract: A magnetostrictive linear displacement detector with increased position resolution includes a magnetostrictive wire anchored at opposite head and foot ends with a reflection termination at the foot end and a damping termination at the head end. A return wire is connected to the foot end of the magnetostrictive wire. The magnetostrictive wire is electrically excited at its head end. A variable position to be detected is represented by a magnet disposed for displacement along the magnetostrictive wire. A torsional motion sensor at the head end generates an electrical indication of the torsional motion within the magnetostrictive wire induced by passage of the electrical excitation by the position of the magnet. The displacement is determined from the interval of time between the detection of the torsional motion traveling directly from the magnet and the detection of the torsional motion reflected from the reflection termination.

Abstract: 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.

Abstract: 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.