Abstract: A level meter for motor vehicle fuel tanks comprises a float element. With the float element, a lever is connected that is adapted to be pivoted about a pivot axis. Further, the level meter comprises a position sensor as well as a position transmitter connected with the lever. At the level of the position sensor, the position transmitter is connected with the lever. The position transmitter cooperates with the position sensor in a contactless manner.

Abstract: A fuel level sensor that includes a housing having a cavity formed therein, and a resistor element disposed within the cavity for creating a signal that may be utilized to indicate a liquid fuel level within a fuel tank. A float lever is associated with the housing adjacent a first end and adjacent a second end with a float is responsive to the level liquid fuel in the fuel tank. The float lever includes a first magnet that is disposed adjacent to the housing. A wiper and contact assembly is positioned generally adjacent to the resistor element to generate a signal that may be used to indicate a liquid fuel level. The wiper and contact assembly includes a second magnet that is magnetically coupled with the first magnet so that movement of the float lever is translated to movement of the wiper and contact assembly.

Abstract: A liquid remaining-amount detecting system includes a displacement transmitting part for transmitting displacement of a float to a rotation-angle sensor and including a bracket mounted to the bottom of a tank, an arm having a base end mounted to the bracket and a front end mounted to the float, and a link mechanism for coupling the rotation-angle sensor and the base end of the arm. The link mechanism serves to cancel displacement of the float resulting from vertical displacement of the bottom of the tank.

Abstract: A detector for detecting the volume of fuel in a fuel tank includes a float for floating on the surface of the fuel, a magnetically conductive member, a magnet, and a sensor for sensing the strength of a magnetic field. The field from the magnet passes through the magnetically conductive member and the sensor is positioned near an outer surface of the magnetically conductive member where it can detect a portion of the field passing through the magnetically conductive member. An arm connects the float to one of the magnetically conductive member and the sensor for moving the one relative to the other. The shape of the magnetically conductive member is a function of the volume of fuel in the tank and the strength of the portion of the magnetic field detected by the sensor is proportional to the fuel in the tank. An output from the sensor controls an indicator that provides a measurement of the fuel in the tank.

Abstract: A liquid remaining-amount detecting system includes a displacement transmitting part for transmitting displacement of a float to a rotation-angle sensor and including a bracket mounted to the bottom of a tank, an arm having a base end mounted to the bracket and a front end mounted to the float, and a link mechanism for coupling the rotation-angle sensor and the base end of the arm. The link mechanism serves to cancel displacement of the float resulting from vertical displacement of the bottom of the tank.

Abstract: Liquid sensing apparatuses and liquid sensing methods are described. In some embodiments, a liquid sensing apparatus includes a magnetic element; a source magnetic field, which produces on the magnetic element a magnetic force with a component that opposes a gravitational force on the magnetic element; and a structure configured to prevent rotation of the magnetic moment of the magnetic element relative to the magnetic field, e.g., so that the magnetic force remains greater than the gravitational force. The apparatus is capable of sensing the level of a liquid using a combination of magnetic force and buoyancy force.

Abstract: A system for detecting the level of liquid in a tank includes a sensor part provided to the tank and for sensing a position of the liquid level in accordance with displacement of a float, and a sensor casing arranged in the tank to be isolated from liquid and for accommodating the sensor part.

Abstract: An adapter for a mechanical type levelmeter, which has a magnet that moves in response to a changing level of liquid in a container. The adapter is fitted onto the levelmeter in a manner that is transparent to any existing reading dials, but that permits hall sensors on the adapter to respond to the motion of the magnet. The adapter also has a processing unit and a transmitter, which process the output of hall sensors and generate a transmittable signal representing level data.

Abstract: A remote two-module electronic fluid monitoring system to be used as an agricultural aid in the application of a fluid to a field. A tank module sits atop a field tank and monitors internal fluid level. Fluid level detection is achieved by tracking the position of an embedded permanent magnet associated with a given internal fluid level within an existing float gauge mechanism. An integrated circuit capable of precisely detecting the orientation of magnetic fields senses the angular position of an existing magnet and outputs an angular field reading to an interfaced microcontroller which then translates angular reading to fluid level. The tank module contains a radio frequency transmitter which then sends fluid level information to a display module mounted within the tractor cab. The display module receives the signal from the tank module and reports to the user the present fluid level remaining in tank via a liquid crystal display.

Abstract: A fuel level sensor is provided having a flexible printed circuit cylinder, having a buoyant member mounted on a rod and a contact member mounted on the buoyant member which abuttingly contacts the rod and the conductive traces formed on the inside of the flexible cylinder wall.

Abstract: A liquid level detecting apparatus in which an error due to a scatter of the temperature characteristics and sensitivity of magnetic sensors is held down is provided which has a float 5 floating on a liquid level, a magnetic member 7 adapted to be turned in accordance with variation of a position of the float 5 accompanied by the fluctuation of the liquid level, and magnetic sensors 8a, 8b adapted to output detection signals varying in accordance with a rotation of the magnetic member 7, the apparatus including two magnetic sensors 8a, 8b, a control unit 100 adapted to receive detection signals outputted from the two magnetic sensors 8a, 8b and compute a liquid quantity value on the basis of the detection signals, and a display unit 102 adapted to shown thereon a liquid level on the basis of the liquid quantity value computed by the control unit 100.

Abstract: A remote two-module electronic fluid monitoring system to be used as an agricultural aid in the application of a fluid to a field. A tank module sits atop a field tank and monitors internal fluid level. Fluid level detection is achieved by tracking the position of an embedded permanent magnet associated with a given internal fluid level within an existing float gauge mechanism. An integrated circuit capable of precisely detecting the orientation of magnetic fields senses the angular position of an existing magnet and outputs an angular field reading to an interfaced microcontroller which then translates angular reading to fluid level. The tank module contains a radio frequency transmitter which then sends fluid level information to a display module mounted within the tractor cab. The display module receives the signal from the tank module and reports to the user the present fluid level remaining in tank via a liquid crystal display.

Abstract: A liquid level indicator for an oil-filled transformer, power choke or tap changer in which a sensor part has a float which rises and falls with the oil level and rotates a sensor shaft and the sensor shaft is coupled to an indicator shaft on which a pointer is provided to cooperate with a dial. The gauge also includes a contactless angle encoder operating with a magnetic hub and coupled to the indicator shaft for outputting a signal representing the oil level.

Abstract: A carburetor fuel level management system includes a fuel level sensor mounted in the float bowl of the carburetor for monitoring actual fuel level and providing a signal indicative of the fuel level. The sensor may be used for data acquisition and/or to provide feedback to a controller which maintains fuel level at or near a preferred level by varying fuel flow rate into the float bowl in response to an indication from the sensor that the actual fuel level differs from the preferred fuel level. Fuel flow rate may be controlled by selectively bypassing a fuel pressure regulator in the carburetor inlet line or by varying voltage to an electric fuel pump, among other methods.

Abstract: A system for monitoring the conditions within a storage tank includes a sensor communicating data indicative of conditions within the storage tank to a base controller. The data is decoded and arranged into a graphical display of the conditions of the storage tank. The graphical display includes a representation of storage tank conditions including the configuration of the storage tank, current fluid levels and temperature within the storage tank. The graphical display also includes a historical database of conditions within the storage tank that may be displayed graphically to track usage. The base controller is connected to a communications network such that data indicative of conditions with the storage tank can be communicated to remote users through a wireless communication network by way of alphanumeric messages.

Abstract: A device for recording the fill level of a liquid inside a container in which an elongated, flexible tubular electrical contact element is arranged, one end area of which is provided with connections at which an electrical signal can be measured. Electrically conductive coatings are disposed on the inner surface of the contact element and facing towards one another, which coatings may be brought into contact with one another by means of a contact producing acquisition element which is disposed on the outside and is movable relative to the flexible contact element.

Abstract: A level meter for motor vehicle fuel tanks comprises a float element (26). With the float element (26), a lever (18) is connected that is adapted to be pivoted about a pivot axis (28). Further, the level meter comprises a position sensor (10) as well as a position transmitter (16) connected with the lever (18). At the level of the position sensor (10), the position transmitter (16) is connected with the lever (18). According to the invention, the position transmitter (16) cooperates with the position sensor (10) in a contactless manner.

Abstract: A safety device for water dispenser includes a magnetic tube, and a float. The tube sticks up on bottom of a water container. A first, and a second magnet switches are disposed in the tube, and connected in series. The float is movably fitted around the tube, and has a magnet ring, which can, when moved close to the first switch, make the first switch become conductible if there is sufficient water in the container. A weighted magnet ring is movably fitted around the tube. The weighted ring is normally close to the second switch due to gravity to make the same become conductible. Therefore, heating device of the dispenser can be activated when there is sufficient water. When the container are made to fall over, the weighted ring moves away from the corresponding switch to leave the same not-conductible, preventing the heating device from being activated.

Abstract: A ceramic resistor card assembly for a fuel sensor includes a card portion made of a ceramic material. The ceramic resistor card assembly also includes a first conductive ink disposed on the card portion to form a fuel level portion. The ceramic resistor card assembly further includes a second conductive ink disposed on the card portion to form at least one contact for the fuel level portion. The first conductive ink is void of Silver and the second conductive ink contains Silver.

Abstract: A liquid level gauge assembly including a dial assembly having a shaped magnet and a removable magnetic detector with a magnetic sensor, preferably a Hall sensor. The dial assembly can provide both visual and electrical signal outputs of the liquid level measured by the gauge assembly. The shaped magnet has a variable thickness which, in cooperation with the Hall sensor, provides a linear output signal from the detector over more than 270 degrees.

Abstract: Refractive encoding of distance or level along a scale provides an advanced means for measuring liquid level or dissimilar-liquid interface level with a float. Distance or level information is encoded in the patterns of microfacets impressed in the scale. The microfacets divide incident visible or infrared beams and direct these multiply divided beams toward or away from detectors disposed in arrays. This approach provides significant reductions in the number of encoding tracks and of the size of the float, improved accuracy, fault detection, increased span, lower friction, and easier installation. A slender rod can replace the wide encoding tape of prior designs. The rod can also be used to guide optical or acoustic signals efficiently from floats to the rod support and thus on to level indicating and recording devices. In addition, the rod support provides means for quick installation, signal coupling, and setting reference levels.

Abstract: A liquid level sender assembly constructed to minimize contact distortion and dither. A housing supports a resistive track and a pivot arm is connected to the housing. The pivot arm has a force transmitting member attached which interacts with a boss on a contact carrier which is also pivotably attached to the case. A space is provided in the fit of boss within the force transmitting member which allows the boss to remain in one position when the pivot arm vibrates in small oscillations, but causes the boss to move in response to larger movements of the pivot arm. Contacts on the contact assembly electrically cooperate with the resistive track to provide a variable resistor. The contact carrier receives only force components directed circumferentially about the axis.

Abstract: A device for recording the fill level of a liquid inside a container in which an elongated, flexible tubular electrical contact element is arranged, one end area of which is provided with connections at which an electrical signal can be measured. Electrically conductive coatings are disposed on the inner surface of the contact element and facing towards one another, which coatings may be brought into contact with one another by means of a contact producing acquisition element which is disposed on the outside and is movable relative to the flexible contact element.

Abstract: A liquid level sensor is provided for use with a container. The sensor protrudes through an opening in the container. The sensor includes a float linked by means of a linkage to a first magnet axially rotatable on a first axis. The first magnet has a magnetic moment with a nonzero component at a right angle to the axis. A divider separates the first magnet from a second magnet having a magnetization and axially rotatable on a second axis. The second magnet has a nonzero magnetic moment at a right angle to the second axis. The first and second magnets are juxtaposed in magnetic linkage so that the second magnet is urged to follow the first magnet in rotation. The divider plugs the opening in the container. A magnetic field sensor is positioned to sense axial magnetic field strength at a location offset from the second axis.

Abstract: A filling level sensor for a liquid container such as a fuel tank for a motor vehicle includes a lever arm having a first end on which a float is mounted and a second end mounted in a support part. A contactless magnetic sensor and a magnetic device are arranged so that the magnetic device moves in response to a deflection of the lever arm due to a change in fill level in the tank and the movement of the magnetic device changes a magnetic field acting on the magnetic sensor so that the magnetic sensor supplies an output signal corresponding to the filling level in the fuel container.

Abstract: A liquid level measuring device for measuring the level of liquid in a storage or dispensing tank has an elongated tubular hollow body that carries a threaded coupler adapted for engaging a threaded nipple on top of the tank. A buoyant float is attached to a lower portion of the elongated body. The body slides in relation to the coupler while the coupler remains stationary in relation to the tank. As the liquid is dispensed from the tank, the buoyant float that was positioned on the surface of the liquid in the tank, lowers in relation to the tank, moving the elongated body into the tank. Measuring indicia placed en the exterior surface of the elongated body allows visual observation of the changing level of liquid in the tank.

Abstract: A fuel level sensor for use with a vehicle fuel tank includes a magnet carrying float assembly that rises and falls with the fuel level to open and close various magnetically activated reed-switches located at different axial positions along a vertically extending electrical circuit. Activating a reed-switch located at a particular vertical position along the electrical circuit causes the overall resistance of the circuit to depend upon the position of the float assembly. The float assembly is capable of freely rotating about the vertical axis of the electrical circuit and carries magnets producing a horizontal magnetic field that can activate a reed-switch from any angular orientation of the float assembly. Thus, assuming the fuel level sensor is provided with a constant voltage source, the sensor is able to determine the fuel level by the amount of electrical current flowing through the circuit.

Abstract: A linear position sensor is provided which employs phase quadrature sensor windings, an excitation winding and a resonator. When an excitation current is applied to the excitation winding, it causes the resonator to resonate which in turn induces signals in the sensor windings. The sensor windings are spatially arranged so that the electromagnetic coupling between them and the resonator varies with the position of the resonator. The excitation windings, phase quadrature windings and resonant circuit are arranged so that the magnetic fields involved in the operation of the position sensor are substantially parallel to each other and the direction of movement of the resonator. Consequently, the effect of rotation of the resonator or lateral movement of it relative to the excitation and phase quadrature windings is alleviated.

Abstract: Multi-symbol refractive encoding of distance or level along a scale provides an advanced means for measuring liquid level or dissimilar-liquid interface level with a float. Distance or level information is encoded in the patterns of microfacets impressed in the scale. The microfacets divide and direct incident visible or infrared beams toward or away from detectors disposed in arrays. This approach provides significant reductions in the number of encoding tracks and of the size of the float, improved accuracy, fault detection, increased span, less friction, and easier installation. A slender rod can replace the wide encoding tape of prior designs. The rod can also be used to guide optical or acoustic signals efficiently from floats to the rod support and thus on to level indicating and recording devices. In addition, the rod support provides means for quick installation, signal coupling, and setting reference levels.

Abstract: A water-monitoring apparatus includes a frame being installed by water. A reel is mounted on the frame. A tension cable is wound on the reel and including a lower end and an upper end. A buoy is connected with the tension cable. A control device is connected with the reel. When the water level changes, the control device rotates the reel so as to adjust a length of the tension cable extending from the reel for allowing the buoy to just float on the water surface. A detecting device is carried via the buoy for detecting at least one environmental characteristic and for producing at least one signal representative of the at least one environmental characteristic. A signal wire is electrically connected with the detecting device. The signal wire includes a helical section for automatically adjusting a distance between its two ends according to the position of the buoy. A monitor device is electrically connected with the signal wire.

Abstract: A liquid level measuring device for measuring the level of liquid in a storage or dispensing tank has an elongated tubular hollow body that carries a threaded coupler adapted for engaging a threaded nipple on top of the tank. A buoyant float is attached to a lower portion of the elongated body. The body slides in relation to the coupler while the coupler remains stationary in relation to the tank. As the liquid is dispensed from the tank, the buoyant float that was positioned on the surface of the liquid in the tank, lowers in relation to the tank, moving the elongated body into the tank. Measuring indicia placed on the exterior surface of the elongated body allows visual observation of the changing level of liquid in the tank.

Abstract: A head for use in a combination float and maximum liquid level gauge. The head has a receptacle for receiving the support member of a float gauge and contains a passageway one end of which is positioned so that it will be exposed to the interior of a LP gas vessel and the other end of a passageway is external of the LP gas container. The exterior end is closed by a valve. The head may be used in conjunction with a dip tube, a float gauge, or a float gauge which has been modified to function as a dip tube to provide a combination fixed liquid level and float gauge.

Abstract: The present invention provides an oscillating liquid level measuring apparatus includes a liquid level measuring unit 10 having: a floating member 3 floating on a surface of liquid 1 in a tank 2; a variable resistor 4 arranged o the top of the tank 2 for measuring a perpendicular displacement of the floating member 3; a transmitting member 5 extending from the floating member 3 and through the top of the tank 2 for transmitting the perpendicular displacement of the floating member 3 to the variable resistor 4; and holders 6 arranged to sandwich the transmitting members 5 for restricting the movement of the floating member 3 only in the perpendicular direction. A connection portion between the transmitting member 5 and the variable resistor 4 has a predetermined allowance 9 in the displacement direction 8 of the floating member 3.

Abstract: A liquid level indicator apparatus provides direct readout of liquid level at high resolution using an array of vertically disposed Hall-effect magnetic switches. To overcome the limit to closer spacing of the switches imposed by their vertical dimension, they a disposed side by side horizontally and vertically by a distance less than the vertical dimension of each switch. They are mounted on a flat flexible substrate and then bent around into a hollow cylinder or prism shape. A floating magnet of annular shape surrounds the cylinder, or a magnet corresponding to the cylindrical or prismatic shape floats inside the surrounding circuit board. Several circuits are shown for displaying a liquid level readout resulting from the actuation of the switches by the magnet.

Abstract: A magnetically operated liquid level indicator of the kind having a magnetized float which moves as the level of liquid changes is disclosed. The indicator has a plurality of magnetized indicator elements disposed one above the other and past which the magnetized float travels as the liquid level rises or falls. The indicator elements are rotatable under the influence of the magnetized float. Weakly magnetized, closely spaced, long, one-piece ceramic magnets are employed as the indicator elements.

Abstract: A liquid density/liquid level meter includes a spring-float system that is coupled with a multiple Hall-sensor configured linear displacement transducer. The spring-float system includes springs that constrain the movement of floats on each end; the spring-float system parameters are mathematically evaluated so as to meet precise performance criteria. The linear displacement transducer includes a magnet and the Hall sensors. The linear displacement transducer and the spring-float system are coupled together within a submerible head unit. When the head unit is immersed in the liquid, the spring-float system moves the magnet, which interacts with the Hall sensors in a lateral slide-by approach that produces an analog voltage that is continuous and linear with respect to the displacement of the magnet. The output from the head unit is communicatively connected to a remote electronic module that contains a signal conditioner with a digital readout.

Abstract: A liquid level sensor is provided that comprises an integral housing including therein a pickup tube, a return tube and a float cavity with a float positioned therein. Sensors are positioned within the float cavity for sensing the position of the float so as to determine the level of liquid within a tank or the like.

Abstract: An apparatus for sensing a level of fluid within a container. The apparatus includes a support coupled to the container. The apparatus additionally includes first and second floats. Each of the first and second floats is pivotally coupled to the support proximate a first end. The apparatus further includes a position sensing mechanism for sensing the relative positions of the first and second floats and responsively determining the level of fluid within the container.

Abstract: A position verification apparatus comprising a movable member disposed within and movable with respect to a housing containing the movable member, a means for generating a magnetic field within the housing, a first magnetically responsive means for sensing the position of the movable member and outputting a signal indicative of the position of the movable member, a second magnetically responsive means for sensing the presence of the movable member and outputting a signal indicative of the position of the movable member and a means for comparing the signal output from the first magnetically responsive means and the signal output from the second magnetically responsive means.

Abstract: A liquid density/liquid level meter includes a spring-float system that is coupled with a multiple Hall-sensor configured linear displacement transducer. The spring-float system includes springs that constrain the movement of floats on each end; the spring-float system parameters are mathematically evaluated so as to meet precise performance criteria. The linear displacement transducer includes a magnet and the Hall sensors. The linear displacement transducer and the spring-float system are coupled together within a submersible head unit. When the head unit is immersed in the liquid, the spring-float system moves the magnet, which interacts with the Hall sensors in a lateral slide-by approach that produces an analog voltage that is continuous and linear with respect to the displacement of the magnet. The output from the head unit is communicatively connected to a remote electronic module that contains a signal conditioner with a digital readout.

Abstract: A liquid level detector that includes an internal tube, a coil wound on an external surface of the internal tube, an external tube, a float ball, a base, and an upper fixing socket. The float ball is disposed in the internal tube, which is wound by a coil on its external surface. The internal tube is enclosed by the external tube, wherein an upper end of the internal tube is connected to the upper fixing socket, while the bottom end is coupled with the base. The two ends of the external tube are sealed for protection of the coil wound on the external wall of the internal tube. When the liquid level detector is employed to detect a liquid level, the float ball in the internal tube will move up or down according to the liquid level, and the induced change in inductance will be converted into a usable signal by a conversion circuit to drive a display apparatus to show the liquid quantity.

Abstract: An apparatus and method for determining the amount of liquid contained in a railroad tank car, or any other liquid storage tank having an interior region defining a predetermined relationship between liquid level and volumetric content. A tube having a closed bottom end is disposed within the tank in a substantially vertical orientation with the closed end of the tube emersed in the liquid and the open end of the tube protruding from the top of tank. An elongate member having a longitudinal edge defining a varying profile corresponding to the predetermined relationship between liquid level and volumetric content is slidably received within the tube. A float is slidable vertically along the exterior of the tube and is magnetically coupled to the elongate member such that as the float rises or falls in response to a change in liquid level, the elongate member will be vertically displaced within the tube.

Abstract: A liquid level control system utilizes a sensor that is attached to a fixed support relative to a liquid container and transmits radio-frequency signals to a remotely located liquid supply system depending upon fluctuations in the liquid level. In the context of a swimming pool, the sensor housing is attached to a sidewall of the pool, at the desired water level. A sensor circuit located within the housing floats at the liquid level, and as changes occur, movement of the floating sensor results in the transmission of signals to either activate or deactivate a supply valve that supplies replacement water to the pool. A small opening located at an upper portion of the sensor housing cooperates with the floating sensor to dampen the motion of the sensor, providing a more accurate reading of the liquid level.

Abstract: A filling level sensor has a carrier part (1) having a lever wire (3) which is attached to a bracket (2) and is axially guided by a bar-shaped apron (11). The bracket (2) has webs (9, 10) which protrude radially with respect to its pivotable and axially nondisplaceable bearing and over which flange elements (7, 8) of the carrier part (1) engage. As a result, the bracket (2) is at a constant distance from the carrier part (1) and is additionally of particularly simple design.

Abstract: A package assembly is formed by applying flux to a device and/or a substrate and inspecting the applied flux to determine whether the amount applied is within a predetermined range. Embodiments include applying a rosin based flux on a laminate substrate and measuring the thickness of the applied flux with an interferometer.

Abstract: A fluid level indicator (22) indicating the level of a fluid (14) in a chamber (12) having a piston (16) is disclosed. The fluid level indicator (12) has a housing (24) that is positioned adjacent to the chamber (12). A plurality of magnetic pins (28, 38) are moveably disposed within the housing (24). The magnetic pins (28, 38) have a first position and a second position. At least one of the magnetic pins (38) shifts from the first position to the second position when the piston (16) is aligned therewith, thereby indicating the position of the piston (16) within the chamber (12) and indicating the level of fluid (14) within the chamber (12).

Abstract: A float for a liquid level detection apparatus including a tube extendable through liquid in a tank. The float is a buoyant body slidably mounted about the tube and having a diameter passable through an aperture in the tank. The float is preferably formed of two separate bodies joined by spacers positioned to allow the body to pivot from a first position substantially axially in line with the tube for insertion and removal of the float with respect to the tank to a second position substantially perpendicular to the tube in operative floating engagement with the liquid surface in the tank. The spacers, in one embodiment, are in the form of pins arranged in pairs along opposite side edges of the two bodies and spaced apart along the length of the two bodies such that the innermost pins of the two pairs of pins define an aperture for mounting the bodies transversely about the tube in the second, floating position.

Abstract: An autonomous apparatus for measuring the amount in volume, weight or level of a liquid in a tank. The invention provides an easy to read digital numerical display in what ever units the user has calibrated it for, indicating the amount of fluid in the tank. The self-contained electronic devise is normally mounted to a pipe nipple on the top of an above ground storage tank. An attached displacement device extends down through the pipe nipple into the liquid to sense the level of the liquid. This device relies on ambient light to power the solar cells and recharge a battery, which provides all the necessary power to operate the device both day and night. The apparatus is designed to be intrinsically safe and totally sealed. As such it operates electrically as a stand alone gauge and is intended as a general purpose indicator of tank contents for any tank location.

Abstract: A time domain reflectometry linear position sensing system having a transmission line with a helically wound inductor and a ground conductor. The transmission line includes a movable member that electrically connects with the ground member and which extends along the inductor from a first end a distance that depends on the position of an object whose position is being determined. A signal generator applies pulses between the first end and the ground conductor and a receiver receives reflections of those pulses. The delays between the applications of pulses and the receptions of reflections depend upon the position of the object. A position determining circuit determines the position of the object based upon the delays, beneficially by using sing-around. Beneficially, a third member extends a predetermined distance along the inductor from a second end. That third member provides a reference delay that can improve the system accuracy.

Abstract: A method and apparatus for determining the position of a movable object along a magnetostrictive wire having first and second opposed ends. A first electrical excitation pulse is applied to a two-wire circuit including the magnetostrictive wire and propagates along the wire to the position of a movable magnet surrounding the wire. The magnet generates oppositely directed first and second torsional waves in the wire. One torsional wave propagates along the wire to a reflective termination at the second end of the wire and is reflected back toward the magnet where it interacts with the magnetic field of the magnet to induce a return electrical pulse in the two-wire circuit. The position of the magnet along the wire is determined from the time differential between the first and second electrical pulses in the two-wire circuit.