Abstract: Described herein is an alarm system for use with a `bag-in-box` arrangement (10) which is used to collect effluent from a processing apparatus (20). The alarm system comprises a chamber (50) located between the processing apparatus (20) and the `bag-in-box` arrangement (10) which includes a level sensor (52) which indicates that the `bag-in-box` arrangement (10) has been overfilled by a predetermined amount and is ready for changing.

Abstract: An apparatus and method for monitoring parameters of combustible liquids within a tank includes a plurality of sensors disposable within the tank for generating signals indicative of parameters of the contents of the tank, a display disposed on the outside of the tank for generating human perceptible signals indicating parameters regarding the contents of the tank, and a nonconductive communications mechanism for conveying signals between the sensors and the display. The sensor generates electrical signals indicative of the parameter(s) measured. The electrical signal is then converted into an optical signal such as pulses of light. The optical signal is conveyed along the electrically nonconductive communications mechanism to the display. The optical signal is then converted back into an electrical signal outside of the tank where it may be processed to produce a human perceptible signal indicative of the parameter(s) measured.

Abstract: An apparatus for is disclosed for detecting low liquid level in a bottom-draining container (12), the apparatus including a spout (14, 48) extended outwardly from the container, the spout having a central bore (18) through which liquid can drain from a bottom of the container; at least one guide member (26, 56, 62) positioned in the spout; at least one float (38) mounted for movement in the spout along the guide member, the float being buoyant in a liquid to be drained from the container; a source (42) for directing a beam of radiation into the spout along a path intersected by the float when a liquid drains to a preselected level within the spout; and a device (44, 46) for detecting when the float intersects the beam. The guide member may be omitted in one embodiment.

Abstract: In accordance with the subject invention, devices and methods are provided for the accurate reporting of movement of an entity. Sensors which are accurate, but provide a delayed signal ("delayed signal sensors"), which delay is unacceptable for many applications, may be used in conjunction with fast sensors ("fast signal sensors"), which are usually subject to drift and other inaccuracies in providing information about a position. Additional sensors which may provide even more accurate and/or less signal sensor delay for a period of time, but which sensor signal is subject to periods of interrupted or undesirable output thereby making it unreliable ("unreliable signal sensors") may also be used in combination with one or more of the delayed signal sensors and fast signal sensors. By using a combination of such sensors, accurate, reliable position information is rapidly obtained to allow high-resolution and/or real-time analysis and depictions of movement.

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 gauge utilizes a liquid tight plastic envelope carrying an elongate p-c board that has a light source mounted so as to direct light laterally thereof, and a light sensor also mounted so as to receive light from a direction which is lateral of the board. The gauge further has a lens configuration which is part of the envelope, for providing a largely solid, reflective path for light which emanates at the light source and is to be received at the light sensor. The lens is capable of aiding in the establishment, at the exterior of the envelope, of a path which diverges from the solid reflective path when the exterior of the envelope is surrounded by liquid that has an index of refraction which is different from the index of refraction of the material of which the lens and envelope are constituted. Assembly is significantly simplified as compared with prior, known gauge constructions.

Abstract: A liquid sensing apparatus for a fuel tank comprises a first optical sensor for producing an output having a first state that corresponds to the first optical sensor being exposed to air and a second state that corresponds to the first optical sensor being exposed to fuel; and a circuit for detecting the first and second optical sensor output states. The sensor circuit also has self test capability for testing both active and passive components. The sensor circuits can be accessed using a two wire only interface, and thermal stability can be achieved with the electronic circuit as shown.

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: A controller has a light source, such as a light emitting diode ("LED") and a photosensitive element, such as a photodiode mounted on a substrate, such as a printed circuit board ("PCB"). The controller also includes a flexible element having a first shape (e.g. a substantially flat shape) and located adjacent to the substrate opposite to the light source and the photosensitive element. The flexible element transfers a first portion of light from the light source to the photosensitive element. On application of a force to the flexible element (e.g. by touching the flexible element), the flexible element deforms elastically from the first shape into a second shape. In the second shape, the flexible element transfers a second portion of light to the photosensitive element. On cessation of application of the first force, the flexible element reverts back to the first shape, and so transfers the first portion of light to the photosensitive element.

Abstract: In a preferred embodiment, a liquid level sensor for use in a hot, pressurized liquid, including: an outer housing suitable for immersion in the liquid; an inner housing disposed within the outer housing and containing therein electronic/electrical components; detection apparatus disposed within the outer housing and the inner housing to detect level of the liquid; a space defined between the outer housing and the inner housing; and means to permit the liquid which migrates through a wall of the outer housing into the space and which is vaporized therein to pass to the ambient surroundings, so as to preclude migration of the liquid through a wall of the inner housing.

Abstract: A liquid level monitor uses a tube to confine a float to a vertical path with a canister containing a lower liquid and an upper liquid which meet at a liquid boundary, the level of which is to be monitored. Light from a light-emitting diode is conveyed to a vertical position of the tube by an optical fiber. A second optical fiber is arranged in a diametrically opposed position of the tube to detect light transmitted across the tube from the first optical fiber. The float is more transmissive than either liquid. When the level of the boundary falls to the level of the optical fibers, received light increases. The second optical fiber conveys this return light to a photodetector, the output of which can be used to trigger an alarm indicating that the boundary level is low.

Abstract: An optical liquid sensing system for sensing liquids in contact with an optical sensing component is provided. The sensing system comprises an optical sensor connected to a control module by a fiber optic cable having two fiber optic strands, the first for receiving light emitted by the control module, and the second for receiving light reflected from a distal reflector. The strands terminate in a longitudinally oriented common ferrule within the optical sensor. The optical sensor is generally cylindrical and includes a distal reflector opposite and in a spaced relationship to the ferrule. A group of apertures is defined in the circumferential wall of the housing so as to permit entry of liquid into the housing and to draw liquid proximally located to the sensor into the housing via capillary action.

Abstract: A binary sensor including a binary sensing circuit, a logic circuit and an adaptive interface card adapted to matingly engage the binary sensor. The binary sensing circuit and logic circuit are operatively coupled for communication with external circuits. The adaptive interface card includes bus network interface circuitry that disables the logic circuit and enables the bus network interface circuitry upon matingly engaging the interface card with the binary sensor. The bus network interface circuitry also becomes operatively coupled with the sensing circuit upon matingly engaging the adaptive interface card with the binary sensor. The bus network interface circuitry of the adaptive interface card provides a means for the binary sensor to communicate with bus networks.

Abstract: An apparatus for sensing whether a liquid with a turbulent surface and contained within a vessel has fallen to a level where the liquid is substantially expended. The apparatus includes a light source for emitting light, a light sensor which is sensitive to the light emitted by the light source and which outputs a signal proportionate to the amount of light sensed, and logic for determining from fluctuations in the signal output by the light sensor when the liquid has fallen to the level in the vessel where the liquid is substantially expended. The fluctuations in the signal are caused by randomness in reflections of the emitted light due to the turbulence of the surface of the liquid. Where the vessel has a closed top and the liquid initially fills the vessel, the logic additionally uses the magnitude of the signal from the light sensor to determine when the liquid has fallen to the level where it is substantially expended.

Abstract: In accordance with the subject invention, devices and methods are provided for the accurate reporting of movement of an entity. Sensors which are accurate, but provide a delayed signal ("delayed signal sensors"), which delay is unacceptable for many applications, may be used in conjunction with fast sensors ("fast signal sensors"), which are usually subject to drift and other inaccuracies in providing information about a position. Additional sensors which may provide even more accurate and/or less signal sensor delay for a period of time, but which sensor signal is subject to periods of interrupted or undesirable output thereby making it unreliable ("unreliable signal sensors") may also be used in combination with one or more of the delayed signal sensors and fast signal sensors. By using a combination of such sensors, accurate, reliable position information is rapidly obtained to allow high-resolution and/or real-time analysis and depictions of movement.

Abstract: An optical tank-level gauge includes an elongated gauge rod magnetically coupled at its lower end to a float for rising and falling with the liquid level. The outer surface of the rod is provided along most of its length with alternating reflecting and non-reflecting circumferential stripes of equal height, the rod having non-reflecting zones at its opposite ends. An optical read head is fixed on the tank and includes LEDs for illuminating the rod and four optical sensors spaced apart longitudinally along the rod and arranged into quadrature pairs relative to the stripes, so that each pair reads a longitudinal extent of the rod substantially equal to the height of one stripe. Each of the non-reflecting end zones has a height such that, in either the full or empty condition, the fields of view of all four optical sensors will be completely within one or the other of the end zones.

Abstract: A device for automatic filling of a mobile container (4) with a material stream (13) from a harvester (1) moving alongside a discharge knee/discharge pipe which is controllably pivotable around a vertical and/or horizontal axis, with a pivotable discharge flap (5) at the end from the harvester (1) to the container (4). At least one optical and/or acoustic range finder (6) for measuring the container (4) and measuring fill levels is disposed on the discharge knee/discharge pipe (3). The range finder (6), either together with the discharge knee/discharge pipe (3) or independently thereof, can be pivoted horizontally and/or vertically.

Abstract: A system is provided for producing a three dimensional object from a reactive liquid medium capable of being solidified. The object is constructed from many successive layers of the solidified reactive liquid medium when subjected to appropriate synergistic stimulation. A reservoir contains both the reactive liquid medium and an underlying supporting, substantially immiscible, non-reactive liquid medium. To begin forming the object, a platform within the reservoir is initially positioned at a depth equal to the thickness of a first layer to be solidified, and continues to support the object being constructed. The synergistic source radiates toward the reactive liquid medium and imaging apparatus defining a three dimensional object of required configuration selectively controls the size and shape of that part of a new two dimensional layer to be solidified. At least part of the new layer is solidified, after which a further layer is applied.

Abstract: Embodiments disclosed herein provide apparatuses and methods for verifying dispense of a fluid from a dispense nozzle. According to one method, a path of electromagnetic radiation from a source to a receiver is obstructed with the fluid dispensed from the dispense nozzle. The intensity of the electromagnetic radiation received by the receiver is measured. The measured intensity is compared with a predetermined intensity to verify the dispense of fluid from the dispense nozzle. One apparatus for verifying dispense of a fluid comprises a source of electromagnetic radiation, and a receiver of the electromagnetic radiation from the source of the electromagnetic radiation operatively associated with the source of the electromagnetic radiation such that the electromagnetic radiation from the source is received by the receiver.

Abstract: A non-intrusive optical transmission liquid monitoring system that detects bubbles in a transparent liquid flowing through a transparent tubing. The system dynamically compensates for changes in optical transmission efficiency of the monitored liquid and distinguishes between the transition from liquid to air and air to liquid. A system comprising a light transmitter and a light sensitive receiver secured on opposite sides of a transparent tubing. The output of the receiver is fed into a self-referencing and drift compensation circuit. The integrated output is connected to circuitry sensitive to a change in the integrated output and triggers one of two possible alarms to indicate a detected transition from liquid to air, or air to liquid.

Abstract: Rotary beverage receptacle-filling apparatus for transparent receptacles has a plurality of receptacle sites spaced apart at its periphery with filling components with electrically driven controls controlling the flow of beverage. Stationary video cameras next to the apparatus measure the filling level in the receptacles near a level limit and to produce closing signals to the flow controls of those receptacle sites at which a receptacle reaches a limit level leading to the desired nominal level, if necessary taking into account any post-flow. One video camera covering several receptacle sites is provided as the measuring device and is connected to an image analyzer driving all controls.

Abstract: A liquid sensing apparatus for a fuel tank comprises a first optical sensor for producing an output having a first state that corresponds to the first optical sensor being exposed to air and a second state that corresponds to the first optical sensor being exposed to fuel; a second optical sensor for producing an output having a first state that corresponds to the second optical sensor being exposed to air or water, and a second state that corresponds to the second optical sensor being exposed to fuel; and a circuit for detecting the first and second optical sensor output states. The sensor circuits can be accessed using a two wire only interface, and thermal stability can be achieved with the electronic circuit as shown.

Abstract: A fluid overfill and identification system uses a pulsed signal to both detect an overfill condition and identify a fluid product contained in a compartment. The pulsed signal is converted into an optical pulsed signal which is used with a retroreflective prism to detect when a fluid in the compartment has reached a desired capacity. Encoded in the pulse width of the same pulsed signal is the specific fluid product located in the compartment. Furthermore, different pulse frequencies are provided depending on whether the tanker truck is at a service station or at a loading terminal, thus allowing the system to distinguish between the two. At a marketing terminal, a new code is loaded into the system as a new fluid product is loaded into a compartment. A residue sensor may detect residual fluid in the compartment, and prevent the loading of a new fluid product and a new ID code.

Abstract: A fuel recovery system warns a user of an impending overflow of fuel and also provides an overflow chamber into which relatively small amount of overfilled fuel are captured, thus preventing fuel spillage into the surrounding environment. The system is adapted for use with a fuel tank attached to a fuel fill line and an overflow line, and comprises a float assembly adapted to be coupled inline to the overflow line; an overflow chamber coupled via a check valve to the main fuel tank; and an optical/electronic warning system for warning the user when fuel in the float assembly rises to a predetermined level.

Abstract: Apparatus for the detection of a phase boundary (10) in a transparent measuring tube (9), in particular of a liquid level in a rising tube (11) (LLD, Liquid Level Detector). The rising tube (11) is illuminated by an illumination device (15) and the light passing through the rising tube (11) is received by a light reception device (17) which converts it into signals dependent on the spatial distribution of the light intensity. A data processing unit (7) is used for processing the signals from the light reception device (17) into information on the height of the liquid level (10) in the rising tube (11).

Abstract: A liquid level detecting device having an overflow reservoir, a flow restriction means and a level detecting means. The reservoir defines a cavity for collecting an electrically-conductive liquid overflowing from a container. This reservoir, which has a low level position associated therewith, includes inlet means through which the overflowing liquid enters, outlet means through which the collected liquid exits, and vent means through which built-up gases escape.Flow restriction means controls the rate at which the collected liquid exits through the reservoir's outlet means. Flow restriction means is calibrated such that the rate at which liquid exits the reservoir does not exceed the rate at which liquid overflows therein.In one embodiment, level detecting means includes a capacitive sensor switch which is fixedly secured to the reservoir to detect whether the liquid level is below the reservoir's low level position.

Abstract: An apparatus for continuously monitoring changes in a liquid level in accance with a differential pressure is provided. A sensor body immersed in the liquid supports two thin-filmed metallic diaphragms that are independently, axially responsive to pressure of the liquid. Each diaphragm has a different modulus of elasticity. Two fiber optic pressure sensors are mounted within an air space encased by the sensor body in combination with the two diaphragms. Each of the two fiber optic pressure sensors detects the axial response of one of the two diaphragms. The displacement difference between the two diaphragms is an indication of differential pressure related to the liquid level.

Abstract: A moisture content measuring apparatus and method wherein a sensor station produces calibration data corresponding to measurements of light at two different wavelengths reflected from a material, and the calibration data is then transferred to a hand held computer. The moisture content of a sample of the material is measured and input to the hand held computer. The process is repeated after changing the wetness of the material, and the hand held computer creates a table correlating reflection data to moisture content. The table is transferred to the sensor station which then continuously generates signals representing moisture content in response to real time reflection data and the table. The cost effectiveness of the sensor stations readily facilitates the use of a dedicated sensor station at each of a plurality of conveyors carrying different materials to be combined into a composite of predetermined proportions by weight.

Abstract: A chemically sensitive sensor capable of detecting changes in concentrations of ions, atoms, or molecules in a fluid environment in which the sensor is immersed or embedded comprises a thin clad optical fiber, which is coated with a polymer which is permeable to liquids and which contains a chemically sensitive material, and a light carrying fiber. The polymeric material has the ability to change color and/or absorbance when the concentration of the ion, atom, or molecule in the surrounding environment changes. The polymer will return to its original color and/or absorbance state once the concentration goes back to the original value. The color change or absorbance is detected through the core of the optical fiber which is connected to a photodetector. The coupling of the light into the sensing structure is obtained by using a core-only optical fiber, surrounded by a clad material, in addition to an external light source.

Abstract: Methods and systems are disclosed for controlling dispensation of hydrocarbon fuels from storage tanks and the like, by employing a sensor in an environment proximal to the dispenser. The sensor preferably includes an optical waveguide having a central axis along which light can transmitted, and the waveguide is disposed in the environment, such that fuel present in the environment contacts at least a portion of the waveguide. The sensor further includes a light source for projecting light into a first end of the waveguide, and a detector for detecting the amount of light propagated through the waveguide. The sensor is electrically connected to a controller which terminates the dispensation of fuel in the event that a leak is detected by the sensor.

Abstract: A semiconductor sensor detects the existence of liquified gases by immersion or approaching the liquid. A high signal amplitude of the sensor permits a simple signal evaluation of high reliability. The sensor permits the realization of filling level measuring devices or level control devices for liquified gases.

Abstract: An automatic water replenishing system is designed for use with multiple dye vats used for tinting eyeglass lenses, but the broad principles of the invention could apply to other systems used for replenishing individual ones of plural vats or reservoirs with water or some other liquid. A rotary water distributor rotates about an arc when it is signaled by water level sensors that the water in a particular vat is low. As the rotary distributor reaches the low reservoir, the LED carried by the distributor actuates a photo transistor adjacent the particular reservoir that needs replenishing, causing the motor to stop and the water supply solenoid valve to be actuated, filling the reservoir until a brief period of time after the level sensor indicates a full condition to the central control system.

Abstract: An optical fiber evanescent wave fuel sensor, employing a light source with a wavelength selected to be at the strong infrared absorption lines of the fuel, typically hydrocarbons. The amount of light leaking from the optical fiber is an exponential function of the length of the fiber in the liquid, and is independent of the relative indices of refraction of the fuel and fiber cladding material.

Abstract: An apparatus for detecting and reporting the presence of liquid on a surface has a detector unit that rests on the surface with the detector unit including at least one pair of spaced-apart electrodes for conductively detecting the liquid, with the detector unit resting on the surface via the electrodes, and with the detector unit further including a sensor that is directed toward the surface and serves for optically detecting the liquid. The apparatus also comprises an operations unit, with the detector unit and the operations unit being electrically interconnected.

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 stereolithographic system for automatically generating three-dimensional objects on a layer by layer basis by alternately forming layers of medium over previously formed layers of the object and selectively solidifying successive layers of medium at a surface of a body of the medium whereby the object is formed from a plurality of solidified and adhered layers. The surface of the body of medium is maintained at a desired working surface, for example by detecting its level and relatively adjusting it and the working surface so that they coincide.

Abstract: An apparatus for protecting and optically isolating the optical element of the probe used for sensing liquid levels includes a tubular body formed from a rigid, non-reflective material which slides over the optical probe. The probe is mounted within the tubular body to create a gap between the shield and the probe in which liquid collects. An open end of the tubular body is cut at an angle and tapers to a point at the widest part of the gap. The tapered point and gap width are arranged so that, when the liquid level falls below the probe end, the surface tension of liquid running down the tapered point overcomes the surface tension of the liquid in the gap and draws the fluid out of the shield.

Abstract: A laser liquid level gauge for detecting the level of the surface of a fluid in a vessel includes an optical unit in the top wall of the vessel and a remotely located control unit. A laser diode at the control unit is amplitude modulated with a frequency tone to produce an incident beam which is carried by a fiber optic cable to the optical unit where it is directed through collimating optics to the fluid boundary. Reflections of the incident beam from the fluid boundary are focused by receiver optics to a photodiode at the optical unit, the output of which is coupled by a cable to the control unit, which includes a phase detector for comparing the phase of the modulation tone with that of the detection signal to produce a level indicating signal for display.

Abstract: Apparatus and methods for stereolithographically forming a three-dimensional object includes a vessel for holding a building material and a smoothing member for forming a uniform coating over a previously formed layer of the object. The smoothing member has a plurality of blades. The smoothing member is swept over a previously formed layer of the object, in at least two directions. Different clearances between the lower surface of the smoothing member and the upper surface of the previously formed layer are used to provide a uniform coating for a subsequent layer over the previously formed layer. The sweeping velocity of the smoothing member can be varied. Retractable needles are attached to the smoothing member for adjusting a blade gap between the lower surface of the smoothing member and the surface of the building material.

Abstract: An intravenous infusion counter/alarm for counting the flow of drips, displaying dynamic speed of dripping, and alarming during malfunction, with at least a main body, an adjusting member which can be received by the main body in order to connect to a drip infusion tube, and a control circuit for providing a light source, light sensing unit, and control signals to detect the flow of dripping, to display the dynamic dripping speed, and to actuate an alarm when the flow deviates from a set value.

Abstract: A system for indicating level of material that includes first and second probes disposed for operative coupling with material whose level is to be sensed. First and second electrical input circuits are respectively coupled to the probes and provide first and second signals. First and second electrical output circuits provide respective indications of material level by operating relay switches. A latch circuit has inputs that receive the respective first and second signals, and an output that changes state only when both first and second signals change state. The output circuits are selectively connected by jumpers either to the associated input circuit or to the latch output.

Abstract: The optoelectronic interface and refractive index display device has a light-emitting diode the light from which is fed through an optical waveguide to a sensing element. A planoconvex lens collimates the light which then passes through a regular cylindrical element to a circular cone. Total reflection occurs at the laterial conical surface thereof when the circular cone is in a gaseous atmosphere. The reflected light is fed through the regular cylindrical element, the planoconvex lens, and then through a common waveguide and receiving waveguide to a photodiode. When the circular cone is immersed wholly or partially in liquid, the light coupled into the sensing element experiences no significant total reflection. The signal generated by photodiode decreases accordingly. The planoconvex lens reduces signal loss.

Abstract: The disclosure pertains to a device for detecting sudden or slow immersion of a body into a swimming pool. More specifically, the invention pertains to a device to detect the accidental immersion of children into swimming pools. In a first embodiment, a first chamber is submerged in the water, and communicates with the water through tubes, so that disturbances in the water not caused by the immersion of a body are damped. A second chamber is in communication with the first chamber and has a sensor disposed inside it. The immersion of a body in the water causes a variation in the air mass contained in the chambers, which is sensed by the sensor which then sounds an alarm.

Abstract: Disclosed is a method and apparatus for preventing or minimizing scale deposition from hard water onto heat transfer surfaces in atmospheric cooling towers, such as those used in air conditioning and refrigeration systems, where evaporative cooling of water provides the necessary heat sink to the atmosphere. An electrical/mechanical control system responsive to changes in density of the water in the evaporative cooling system operates to permit discharge of water containing dissolved and suspended solids from the system when its density reaches a predetermined maximum value and to discontinue the discharge of cooling system water when its density reaches a predetermined minimum value. Water drained from the cooling system is replaced by fresh water, preferably by water containing chemical additives to increase solubility of hard water minerals in the cooling water.

Abstract: A bubble detector for a liquid stream flowing within a conduit comprising a walled chamber communicating with the conduit interior, the chamber being positioned to trap and accumulate bubbles entrained with the liquid stream. A window in the chamber wall for optically examining the chamber, the window having its inner surface positioned to provide an interface with the chamber contents. Means for distinguishing between liquid and gas in the chamber comprising a light source positioned to direct its light toward the window inner surface, and a light sensor oriented to receive light reflected from the window inner surface the light source being positioned at such angle to the window inner surface that transmission of light with refraction occurs when liquid is present in the chamber and total internal reflection occurs when gas is present in the chamber. And an output device responding to the sensor for taking an action when a predetermined volume of bubbles have accumulated in the chamber.

Abstract: Two types of optical liquid level sensor are disclosed. In the first refractive-type (20,65), light is selectively refracted by the particular fluid(s) in a plug recess between primary and secondary detectors (D.sub.1,D.sub.2). The output signal from either detector indicates whether the sensor is above or below the liquid level. The signals of the respective detectors are cross-compared and used to corroborate one another. In the second absorptive-type (100), light at a particular wavelength is passed through a body chamber (86'), which is exposed to the liquid whose level is to be sensed. Such light is selectively absorbed by the liquid. A detector (D) is arranged to measure the intensity of such light as has passed through the chamber, and to indicate the level of liquid in said chamber.

Abstract: A liquid level sensor assembly for a liquid-chemical bubbler includes a removable cylindrical LED housing, which is removably retained within a cylindrical axial bore of a sealing nut. The LED housing is removable from within the cylindrical axial bore without breaking the seal between the chemical liquid within the bubbler and the ambient atmosphere. The LED housing holds an LED transmitter and a photodiode detector, which respectively sends light into a cylindrical quartz rod and receives reflected light from the quartz rod, where the reflected light is used to measure the level of the chemical liquid within the bubbler.

Abstract: It is a warning device for a given liquid level in any dripping bottle; the device is furnished with a photo-electronic sensor, which can, through a detecting hole, sense the liquid level of a dripping bottle, and then sends a signal to a control circuit to drive a buzzer to generate a sound signal, whereby the nurse or the like is to be reminded that the liquid will be used up soon.

Abstract: The problem of measuring oil film thickness in a rotating housing (66) is solved using a noncontact liquid film thickness sensor. The housing (66) is rotatable about an axis (58) and includes a cylindrical outer wall coaxial to the axis. A plurality of U-shaped glass rods (70) are within the rotating housing (66) and have opposite legs (72, 74) mounted through openings in the outer wall. At least one leg (72) of each rod (70) is coplanar with a similar leg of each other rod. Each rod (70) has a different length between its opposite legs (72, 74). A light source (76) is provided outwardly of the housing (66) and coplanar with the coplanar legs (72). A sight glass (80) or other sensing device is provided outwardly of the housing (66) proximate the path of movement of the opposite leg (74) of each of the rods.

Abstract: A system for automatic and real time detection of the presence or absence of a substance in an environment by monitoring variations in light energy transmitted through an optical fiber having a specially processed sensitive probe area. The sensitive probe area is positioned on, about or within the environment where a substance is to be detected. Because of differences in optical indices of refraction and energy absorption characteristics of different substances, the presence of different substances at the processed sensitive area will cause different proportional and characteristic attenuation of the light energy passing through the optical fiber. Changes in light energy transmission can be interpreted automatically to provide an indication of the condition of an environment.