Abstract: A system of liquid level detection has a vessel, a sight glass in fluid communication with the vessel, a float positioned in the sight glass, a proximity switch affixed exterior of the sight glass for transmitting a signal relative to a sensing of the float in proximity to the proximity switch, a timer cooperative with the proximity switch for measuring a period of time relative to the signal from the proximity switch, and an indicator cooperative with the timer for producing a humanly perceivable indication when the period of time is at a predetermined limit. The proximity switch can be positioned so as to detect a low level of liquid in the vessel or a high level of liquid in the vessel.

Abstract: A vehicle cesspool level sensor includes a mounting base, a stainless steel detection tube welded to the bottom side of the mounting base to hold a detection circuit on the inside, an end cap welded to the bottom end of the stainless steel detection tube, a float axially movably mounted the detection tube and movable, the float having two magnets symmetrically disposed at two sides and adapted to induce the detection circuit, a stainless steel strainer fastened with the top end to an endless locating flange at the bottom side of the mounting base, and a strainer cover capped on the bottom end of the stainless steel strainer and fastened to the end cap with a screw.

Abstract: In a tank for liquid fuel, particularly a tank for LPG in a system for supply of LPG to the internal-combustion engine of a motor vehicle, the level-sensor device comprises a floating member guided so as to move in a substantially vertical direction within the tank according to the variations of level, and transducer means consisting of an aligned series of reed relays that are activated selectively by one or more permanent magnets carried by the floating member.

Abstract: A device indicates the level of concrete within the hopper of a concrete pump and prevent accidental overflow and spills. The concrete level indicator device includes an elongate post with an enlarge float fixed to the bottom end and a guide sleeve for allowing vertical telescoping movement of the post as the concrete level in this hopper changes. A retaining collar attaches to a screen in the hopper of the pump and surrounds the guide sleeve for limiting swinging movement of the post and guide sleeve, thereby maintaining the device in a vertical position within the hopper with the float resting on the concrete. As concrete is filled into the hopper, the post rises through the guide sleeve until a visual indicator (e.g. a red band) on the top end of the post is visibly exposed above the guide sleeve, thereby alerting the operator to interrupt the discharge of concrete being filled in the hopper until the concrete level drops and the visible indicator on the post is no longer visible.

Abstract: A flexible liquid level sensor board assembly for application with liquid level sending units is presented. The liquid level sending unit includes a stem, float, and a flexible sensor board assembly. The flexible sensor board assembly is a distinct component of the sending unit and as such is capable of repeated insertion and removal from the stem. The flexible sensor board assembly is therefore ideal for existing/retrofit applications and new installations alike.

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: In a fuel tank level sensor 1 for measuring a remaining amount of fuel in accordance with a resistance value which is varied by moving a rheostat 1a utilizing a float 1c that vertically moves according to increase and decrease of the fuel in a fuel tank 2, change in resistance value of the rheostat 1a includes a linear range in which the resistance value linearly varies with the increase and decrease of the fuel, and a non-linear range in which the resistance value discontinuously varies under full-tank conditions where the fuel tank is substantially filled up with the fuel. Even upon undesirable increase of the resistance value of the rheostat 1a as a result of deposition of sulfides, the sensor 1 can always detect accurately that the fuel tank 2 is filled up.

Abstract: A tank liquid level or volume gauge for use with volatile materials, such as propane, stored under pressure as liquid and released as gas, includes a float with a float magnet that couples with a liquid level indicator magnet across a fluid impermeable wall to provide indication of tank liquid level or volume. In another embodiment, when a predetermined tank liquid level or volume is reached during filling, the float actuates an inlet closure valve to increase inlet flow resistance, creating a shutoff signal.

Abstract: A level gauge (1) for measuring the amount of liquid in a tank, such as a ground tank (19) containing fuel (21, is disclosed. The level gauge (10 comprises a probe (2) having a pressure sensor based on registration of hydrostatic pressure differential between the liquid and the tank atmosphere. The probe (2) is submersed in the liquid and is located adjacent to the bottom of the tank. The probe (2) is in tank atmospheric communication with an air trap (4), which is located in the tank atmosphere above the surface of the body of liquid.

Abstract: A non-contact type liquid level sensor includes a sensor housing; a rotary shaft, rotatably mounted on the sensor housing; a float, vertically movable with a change of a liquid level; a float arm, having a first end mounted on the float, and a second end coupled to the rotary shaft such that the rotary shaft is rotated with a vertical movement of the float; an annular magnet, coupled to the rotary shaft, and rotating together with the rotary shaft; a pair of arcuate stators, disposed in the sensor housing so as to confront an outer peripheral surface of the magnet; and a magnetoelectric transducing element, disposed between the first ends of the stators, for detecting a change of a magnetic flux density in the stators, which is caused by a turn of the magnet, and for converting the detected change of the magnetic flux density into an electrical signal. Second ends of the stators are spaced from each other to form a gap having an opening angle within a range from 50° to 200°.

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 redundant level measuring system comprises a chamber for fluidic coupling to a process vessel whereby material level in the vessel equalizes with material level in the chamber. A float including a magnet in the chamber rises and falls with material level in the chamber. A magnet actuated visual indicator is mounted to the chamber for indicating level of the magnet in the chamber. A measurement instrument includes a probe and a measurement circuit. The instrument is mounted atop the chamber with the probe extending downwardly into the chamber. The measurement circuit measures a characteristic of the probe representing level of the material in the chamber. A shield in the chamber isolate the float from the probe.

Abstract: In a slide detector, a contact member provided on a slider is made of gold or a gold alloy including an abrasion resistant metallic component, and a plurality of electrodes provided on an electric insulating board is made of a silver alloy including glass. Preferably, the contact member sliding on the electrodes is made of a gold alloy consisting of 99% by weight of gold and 1% by weight of cobalt, so that an anti-sulfurization and an abrasion resistance between the contact member and the electrodes is ensured. However, the weight percent of gold and other alloys may vary depending upon the abrasion characteristics desired.

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: During the determination of a fill level of liquid in a container, a measuring chamber, in which there is initially the same fill level as in the container, is completely filled with liquid. The time required for completely filling the measuring chamber is measured and compared with previously determined values. The fill level in the container is then determined by comparison of the measured values with the known values.

Abstract: An apparatus for measuring a fluid level in a tank comprises a housing including a level indicator for displaying a measured fluid level in the tank. A rod extends from the housing and a float is adapted to travel along the rod. A first end of an elongated flexible member is attached to the float and an opposite end of the elongated flexible member is attached to a spool. The spool stores at least a portion of the elongated flexible member. The apparatus further includes a spring adapted to urge the spool to automatically uptake portions of the elongated flexible member as the float travels towards the housing and to allow the elongated flexible member to unwind from the spool as the float travels away from the housing.

Abstract: A liquid level change indicator is described as an apparatus, which generates a visual indication when a liquid level in a controlled vessel has changed and indicates amount of change for a timed period. Operation of the instrument entails positioning the apparatus in the liquid containment vessel from a support chain. Positioning, is accomplished by a course chain adjustment, followed by a fine-threaded-nut adjustment. A float centering itself in a concentric circle sight gauge indicates initial correct monitoring position. Deviation from the bulls eye of the concentric ring site gauge constitutes a liquid level change. Each concentric ring indicates a larger level change relative to the innermost sight ring per unit test time.

Abstract: A piston pump elevator having fluid level measurement capability which is capable of providing an electrical signal proportional to the approximate amount of fluid remaining in a container from which fluid is being withdrawn.

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: An improved armless fluid level measuring device has a sealed housing tube and an externally exposed float. The float is slidably attached to the outer surface of the housing tube in which an elongated PC board is sealedly confined so as to protect the PC board from being sabotaged or eroded by fluid chemicals. The float provided with a plurality of high density magnet is slidable on the external surface of the housing tube. The PC board has a circuitry made up of serially connected resistors that are serially bridged together by way of magnet-controlled switches which are activated as the float is variably positioned in place by the fluid confined in a container whereby the serially connected resistors can form a closed circuitry to indicate the level of the fluid in a container via readings on a display of a gauge.

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 tank liquid level or volume gauge for use with volatile materials, such as propane, stored under pressure as liquid and released as gas, includes a float with a float magnet that couples with a liquid level indicator magnet across a fluid impermeable wall to provide indication of tank liquid level or volume. In another embodiment, when a predetermined tank liquid level or volume is reached during filling, the float actuates an inlet closure valve to increase inlet flow resistance, creating a shutoff signal.

Abstract: In a slide detector, a contact member provided on a slider is made of gold or a gold alloy including an abrasion resistant metallic component, and a plurality of electrodes provided on an electric insulating board is made of a silver alloy including glass. Preferably, the contact member sliding on the electrodes is made of a gold alloy consisting of 99% by weight of gold and 1% by weight of cobalt, so that an anti-sulfurization and an abrasion resistance between the contact member and the electrodes is ensured. However, the weight percent of gold and other alloys may vary depending upon the abrasion characteristics desired.

Abstract: A system for recovering oil from a body of water (e.g. river, lake, or sea) includes (i) an inlet unit 10 having a hopper-shaped main body and floaters 12 attached to the hopper by tugs 11; and (ii) a segregation tank 15 having (a) an inlet pipe 14 to receive oil-contaminated water from the inlet unit, (b) a first discharge pipe 17 with pump 20 therein for delivering oil to an oil tank, and (c) a second discharge pipe 18 for delivering water from the segregation tank. The discharge pipes include respective valves 21, 22 therein. A sensing unit 100 (e.g. ultrasonic transducer) and a panel sensing unit 110 are provided in the segregation tank for determining the level of oil in the tank. A controller including a microprocessor 200 controls the discharge valves 21, 22 in response to signals received from both sensing units 100, 110.

Abstract: Disclosed herein is a fuel sensor suited for sensing the level of fuel in a motor vehicle fuel tank. The fuel tank includes an interior mounting to which the fuel sensor is affixed. The fuel sensor has a cantilever member extending in a substantially horizontal direction from the mounting to a free end. The cantilever member is substantially rigid but can be deflected in the vertical direction. A probe is affixed at the free end of the cantilever member to extend in a substantially vertical orientation approximately the full height of the fuel tank. A stabilizer member is affixed at one end to the mounting and at an opposing end to the probe. The stabilizer member has a pivot segment between the ends permitting the probe to move vertically but not horizontally. According to Archimedes's principle, the probe encounters a buoyant force equal to the weight of displaced fuel which induces strain in the cantilever member.

Abstract: In one embodiment, a relative location detection apparatus including a detection unit having a support board having a plurality of spaced reed switches mounted along a lengthwise axis of the support board. Each of the reed switches has a longitudinal axis oriented substantially perpendicular to the lengthwise axis of the support board. A high intensity magnet is coupled to the support board for movement relative to the support board and in a direction substantially parallel to the support board's lengthwise axis. The magnet has north and south poles that are oppositely positioned to one another and directed toward one another across a width of the support board and into periodic alignment with the longitudinal axes of the reed switches. The magnet has a magnetic force sufficiently focused so that the magnet actuates the reed switches individually thereby indicating the magnet's location.

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: An oil spill prevention apparatus for use with for a domestic oil storage tank has a catchment tray e located underneath an oil storage tank and extending over the entire footprint thereof. The catchment tray has a depression for pooling oil caught by the catchment tray. A level sensor for raises an alarm when the oil level in said depression exceeds a threshold value.

Abstract: Two embodiments of an analog liquid level sensor are provided for measuring the level of a liquid in a container having a volume/depth relationship wherein each sensor has a resistance-to-float-displacement profile matched to the volume/depth relationship of the container. Each sensor includes a dielectric coated metal bar which acts as a heat sink and a ground plane. A pair of electrically spaced terminals and a printed circuit including a thick film resistor pattern and a metallization pattern having metallized graduations are formed on the metal bar for reduced electrical noise characteristics and improved hysteresis. The resistance of the resistor pattern is electrically coupled between the terminals and has a resistance which varies at different positions between the terminals. The metallization pattern is formed on the resistor pattern which, in turn, is formed on opposite sides of the dielectric coated metal bar.

Abstract: Liquid level indicators include an upright cylindrical tube of non-magnetic material, a cylindrical, permanent first magnet element aligned with and movable coaxially within the tube, a float, and an annular, permanent second magnet element aligned with and movable coaxially outside the tube. The first and second magnet elements have magnetic fields in alignment with one another, with one of the first and second magnet elements being carried by the float. The first and second magnet elements are axially spaced relative to one another such that the one magnet element which is carried by the float supports by magnetic attraction the other magnet element which is not carried by the float.

Abstract: A float for a level sensor has a center through hole and a position limiting hole formed in an upper portion of the center through hole and having a larger diameter than the center through hole, and an annular hollow space opening downward. An inner annular groove is formed in a wall defined between the center through hole and the annular hollow space, and an outer annular groove is formed in an outer wall defining the annular hollow space for disposing a magnet ring, an inner gasket and an outer gasket for facilitating closing an annular cap on the two gaskets. An oval base with a magnet ring is fixed in the position limiting hole. Then this float may be combined with various types of level sensors without any extra processes or modifications.

Abstract: A fluid level measuring device for measuring a fluid filling level in a container contains a float disposed in the container and a magnet disposed in the container. The magnet is coupled to the float in terms of movement and, in the event of a change in the fluid filling level, executes a movement that corresponds to a change in fluid level. A magnetic field sensor is disposed in a zone of influence of a magnetic field generated by the magnet and outputs an electrical signal which is representative of a height of the fluid level.

Abstract: Liquid level lever gauge with a hinged counterweight segment, or a hinged float arm segment or both a hinged float arm segment and a hinged counterweight segment. The invention permits lever arm gauges to be used in liquid storage tanks having small openings through which the gauge can be inserted.

Abstract: The invention provides an improved float and float system for use in the monitoring of fluid levels, particularly in small diameter wells by way of a cable and float system. The float system includes a number of centralizers which hold the float cable near the center of the well casing and thus reduce the friction of the cable on the casing walls. The addition of weights on the float cable, either or both below the float and between the float and the top of the well casing, can improve the accuracy and operation of the system even further. A truncated cone-shaped float is provided, with a number of fins displaced evenly around the circumference of the float.

Abstract: Improved apparatus and methods for forming a layer of material over a surface of a previously-formed cross-section of a three-dimensional object in anticipation of forming a next cross-section of the object out of the layer. A volume of material, including at least some excess material, is placed over the surface, and the excess material is swept off by placing the excess material in the predetermined path of a sweeping member, the path being substantially in a plane spaced from a working surface of material. The member may be directed to sweep the excess material away through a successive number of sweeps, which may vary for each cross-section, at least a velocity which may vary for each sweep. Additionally, the clearance between the member and the surface of the previous cross-section may vary for each sweep. A "winged" member is also provided, comprising two legs extending from a base, and a "Trident" embodiment is also provided, comprising three legs extending from a base.

Abstract: A valve assembly and a bottom-draining container having the valve assembly. The valve assembly comprising a first body member, a guide member supported by the first body member so that the guide member will extend upward into the container, and a float mounted for movement along the guide member, the float being buoyant in a liquid to be drained from the container, the float having a mating surface for engaging a second mating surface on the valve assembly when the float is in the unsensed position, the mating surface of the float having a configuration for minimizing sticking of the float with respect to the valve assembly.

Abstract: A liquid level alarm system is activated when liquid in a container falls below a predetermined level. The system contains an alarm located outside the container. The alarm is electrically connected to a switching device. The switching device may have a push-down button located on the top, an "on-off" switch located on the side, or a sliding switch located on the side. When the switch is pushed down, the switching device activates the alarm. The container has a vertically positioned rod adjacent the switching device. There is a float slidably connected to the rod by a connecting rod and hook. The float rises and falls with the level of the liquid. On the side of the rod opposite the float there is a switch contact which makes contact with the switch when the level of the liquid falls below a predetermined level and the float is no longer supported by the liquid.

Abstract: An apparatus for measuring liquid level in a container, the apparatus having a flexible measurement scale attached at one end to a weight for retainment at the bottom of the container and at the opposite end to a receiver at the top of the container. A float moves along the flexible scale, and has a configuration and density designed to place a portion of the float below the level of the liquid to be measured and a portion above the liquid level. The portion above the liquid level contains transmitter apparatus for applying energy to one side of the scale, and detection apparatus on the other side for detecting energy transmitted through the scale and converting it to a liquid level in the container.

Abstract: A liquid level alarm system is activated when liquid in a container falls below a predetermined level. The system contains an alarm located outside the container. The alarm is electrically connected to a switching device. The switching device may have a push-down button located on the top, an "on-off" switch located on the side, or a sliding switch located on the side. When the switch is pushed down, the switching device activates the alarm. In one embodiment, the container has a vertically positioned rod adjacent the switching device. There is a float slidably connected to the rod by a connecting rod and hook. The float rises and falls with the level of the liquid. On the side of the rod opposite the float there is a switch contact which makes contact with the switch when the level of the liquid falls below a predetermined level and the float is no longer supported by the liquid.

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 railroad tank car containing liquid, has a tube through its top, with the closed lower end of the tube in the liquid. A float slidable along the tube exterior is magnetically coupled to an ultrasound reflector piston inside the tube so that, when the tube is in the liquid in the tank, the float determines the height of the piston inside the tube. An ultrasonic transducer atop the tube sends pulses down the tube and which are reflected by the piston to the transducer. A computer coupled to the transducer determines and displays the liquid level. The piston is cup-shaped with a known distance between reflecting surfaces for use in the computer to produce a display value corrected for temperature variations.

Abstract: Improved apparatus and methods for forming a layer of material over a surface of a previously-formed cross-section of a three-dimensional object in anticipation of forming a next cross-section of the object out of the layer. A volume of material, including at least some excess material, is placed over the surface, and the excess material is swept off by placing the excess material in the predetermined path of a sweeping member, the path being substantially in a plane spaced from a working surface of material. The member may be directed to sweep the excess material away through a successive number of sweeps, which may vary for each cross-section, at least a velocity which may vary for each sweep. Additionally, the clearance between the member and the surface of the previous cross-section may vary for each sweep. A "winged" member is also provided, comprising two legs extending from a base, and a "Trident" embodiment is also provided, comprising three legs extending from a base.

Abstract: A liquid level sensor for a tank includes coaxial inner and outer tubes having lower ends extending into the tank and upper ends projecting from the tank, with the upper end of the inner tube projecting from the outer tube and disposed a known distance from the top of the tank. A switch assembly includes a switch disposed in the inner tube and operable in response to proximity to a switch actuator which is carried by a float encircling the outer tube and movable therealong with the liquid level, the switch being connected across a pair of electrical conductors extending from the upper end of the inner tube. An indicator strip extends lengthwise of the conductors and is held thereagainst by a transparent sleeve, the strip having indicia indicating distance to the switch. Plastic cable ties extend through openings in the inner tube and snugly hold the switch assembly against the inner tube to permit manual axial movement of the switch assembly while preventing inadvertent movement thereof.

Abstract: A universal read head for a tank-level float gauge is adapted for use with any of certain different types of gauge rods which may be connected to a float element in the tank, including rods having an optical code thereon including a plurality of alternating reflecting and non-reflecting stripes arranged between magnetic end portions, and a rod with one or more magnets disposed adjacent to each end thereof and longitudinally spaced magnets intermediate the ends. The sensing head includes an LED light source for illuminating the rod and two phototransistors coupled in quadrature relationship for detecting the illuminated optical code patterns, and two magnetic reed switches for sensing the proximity of magnets on the gauge rod. The sensors are coupled to a microprocessor for interpreting the electrical signals generated by the sensors to identify the type of gauge rod being used and to provide an indication of the position of the gauge rod relative to the sensors.

Abstract: Both ends of a sensing probe are sealed by an assembly including a fixing disk, a sensing probe, a sensing circuit, a floating collar and an external tube is provided. The fixing disk is provided with a threaded opening in which one end of the sensing probe is fixedly attached. The sensing probe is built-in with a sensing circuit. A floating collar is movably enveloped onto the sensing probe. The external tube is further attached to the fixing disk and the inner diameter of the external tube is larger than the outer diameter of the floating collar. The other end of the sensing probe is provided with an inner threaded portion. A locking cover is provided with a pair of openings and a post in a central portion. The post is provided with an external threaded portion in which the inner threaded portion of the sensing probe can be engaged. The post further includes a threaded recess in which a bolt having a small collar can be attached. The fixing disk further includes an annular extension at its bottom.

Abstract: The present invention is a sewer back-up indicator that is positioned within the hole in the cover of the manhole. The indicator includes a bushing and a rod having a valve at one end and an inflatable balloon at the other. The valve is adapted to receive a gas source which supplies the gas down the length of the rod into the balloon, thus inflating the balloon. When the balloon is in the deflated state, the device can be inserted into position within the hole in the manhole cover and subsequently removed from this position without lifting or removing the cover from the manhole. Connected to the other end of the valve is a flexible member that carries a flag having a legend thereon. When the device is in its up position, the flag and flexible member indicate that fluid within the manhole has risen, thus signaling a potential back-up.

Abstract: A magnetostrictive position sensing device is disclosed where a probe assembly surrounding a waveguide is anchored at one end to the bottom of a tank and terminates in a transducer assembly attached to the top of the tank. The probe assembly compensates for differential coupling between two sections of the probe assembly. The sensing device also includes one or more fluid level floats movably surrounding a portion of the probe.

Abstract: A method and apparatus for measuring a liquid level using a liquid level gauge having reed switches to determine the position of a magnetic float. Firstly, providing an elongate float having an axial bore defining a longitudinal axis. The float has a plurality of magnets axially spaced along the longitudinal axis to form magnetic layers. Secondly, providing a tube having a first end and a second end. A plurality of magnetically activated reed switches are equally axially spaced from the first end to the second end. The tube extends through the axial bore of the float. Thirdly, determining which of the plurality of magnetically activated reed switches have been activated by the axially spaced magnetic layers of the float and interpolating float position in relation to the activated reed switches.

Abstract: Method and apparatus for determining the doubling in volume of a rising dough includes a horizontal beam placed across the edge of the bowl which has a retaining notch for a vertical calibrated stick whose end is placed on the top of the dough to ascertain its volume either in an unrisen or risen condition. Since the bowl has nonvertical or sloping sides, the measuring stick is calibrated with a nonlinear scale to compensate or to correspond to the sloping sides. Thus the measuring stick has marked on its scale, for example, the number of cups of dough in the bowl. A measurement is initially made before the dough has risen and then doubled to provide the user with a measurable number which periodic checking will indicate when the dough has increased to that desired volume.