Abstract: An indicating device is disclosed for showing the level of a fluid in a container. A transparent rod having a sensing end is immersed in the fluid when the container is filled above a predetermined level. The sensing end is shaped to cause a substantially total reflection of a beam of light projected in the rod from an opposite end of the rod when the sensing end is not in contact with the flowable substance. A light source and photoelectric detector are arranged at the opposite end of the rod and a circuit is connected to the photoelectric detector for detecting when a predetermined amount of reflection occurs and also for preventing response of the device to slopping of the fluid to and fro in the container.

Abstract: A system and method are disclosed for monitoring the growth of a crystalline-body from a liquid meniscus in a furnace. The system provides an improved human/machine interface so as to reduce operator stress, strain and fatigue while improving the conditions for observation and control of the growing process. The system comprises suitable optics for forming an image of the meniscus and body wherein the image is anamorphic so that the entire meniscus can be viewed with good resolution in both the width and height dimensions. The system also comprises a video display for displaying the anamorphic image. The video display includes means for enhancing the contrast between any two contrasting points in the image. The video display also comprises a signal averager for averaging the intensity of at least one preselected portions of the image. The value of the average intensity, can in turn be utilized to control the growth of the body.

Abstract: A device for producing a light signal corresponding to the refractive index of a fluid medium comprises an elongated light-conducting body consisting of an input section and an output section connected to each other by an intermediate curved section adapted for immersion in said fluid. This curved section is provided with a plurality of curvatures arranged successively and bent alternately in opposite directions, whereby light passing by refraction into said fluid undergoes a notably greater variation, as a function of the refractive index of said fluid medium, than can be obtained with a curved section bent in a simple direction. A light signal is thus provided with a high sensitivity. The complex-curved, preferably .OMEGA.-shaped, section can be enclosed in an envelope composed in part of filter material.

Abstract: An apparatus for monitoring and detecting a preselected liquid level of a liquid in a container comprises a light emitter element disposed at a height along the outer wall of the liquid container and a light sensitive element disposed in opposition to the light emitter element at such a height that the light beam emitted from the light emitter element will impinge onto the light sensitive element when the liquid level in the container has attained the preselected liquid level, wherein change in the output state of the light sensitive element is utilized for producing an alarm signal.

Abstract: In this fluid dispensing control system, the size of a container to be filled is established by a set of photosensors mounted on the dispenser housing. Discrimination circuitry distinguishes between ambient light level and light reflected from the container that is placed under the spout. Delay and lock-out circuitry is provided to insure that an erroneous size-indicating signal is not generated as the container is moved into position, and to insure that the size-indicating signal does not change once pouring has begun. Timer circuitry controls the pouring duration and insures complete, uniform filling of each size container. Counter and display circuitry tallies the number of containers, of each size that have been filled, and indicates the total volume of fluid that has been dispensed.

Abstract: An electrooptical instrument for detecting the presence of liquid and a method of operating the same, comprising at least one monochromatic infrared source, a light conductor which totally reflects infrared radiation from at least one surface thereof, an infrared detector, and signal processing circuitry. According to the invention the infrared source has a maximum radiation strength of less than 200 mW/sterad, the main maximum in the angular distribution of the infrared radiation is at least approximately axially symmetric and oriented in the direction of the optical axis of the light conductor, and the angular distribution of the infrared radiation is such that the intensity falls off to half its maximum value less than 4.degree. away from the symmetry axis. An electronic circuit causes the system to oscillate when no liquid is present. The instrument may be operated in a self-monitoring mode by monitoring the oscillations with two monostable multivibrators connected in parallel.

Abstract: A flow indicating attachment for a transparent rotameter column containing a visible float movable in accordance with the rate of fluid flow through the column consists of a reciprocating scanner moving parallel to the column in a flow rate range including the range of float movement and coupled to a potentiometer forming a synchronous analog scanning signal which is furnished to a recorder. The scanner has a photoelectric float-sensing assembly including a photocell connected in the analog scanning signal circuit. When the sensing assembly is shaded by the rotameter float, it produces an abrupt dip in the recorded analog scanning signal, thus providing a recorded indication of the float's position in the range covered by the track of the reciprocating scanner.

Abstract: Monitoring the level of both opaque and clear liquids in a reservoir without contacting the liquids by providing first and second reservoir wall portions that define a region through which a light beam is passed from a light source to a light sensor so that opaque liquid extinguishes the light beam and so that the wall portions cooperate with the clear liquid to refract the light beam away from the sensor. A monitoring line segment, defined as the portion of a hypothetically unrefracted and unreflected light beam between the first and second reservoir wall portions, is a small fraction of the largest interior linear dimension of the reservoir in a plane containing the monitoring line segment and a line normal to the first reservoir wall portion.

Abstract: A device for producing a light signal corresponding to the refractive index of a fluid medium comprises an elongated light-conducting body consisting of an input section and an an output section connected to each other by an intermediate curved section adapted for immersion in said fluid. This curved section is provided with a plurality of curvatures arranged successively and bent alternately in opposite directions, whereby light passing by refraction into said fluid undergoes a notably greater variation, as a function of the refractive index of said fluid medium, than can be obtained with a curved section bent in a simple direction. A light signal is thus provided with a high sensitivity.

Abstract: An apparatus and method are disclosed for measuring the amounts of a coating material on an applicator roll. A beam of light is projected so that only a first portion thereof is intercepted by the coating material on the applicator roll. At least a fraction of the remaining light portion passes through an aperture defined by a slotted shield member and the coated roll surface, said fraction varying with the thickness of said material on the roll surface, and detector means disposed to measure said variable fraction.

Abstract: Level indicating devices wherein at least a side portion of a bubble cavity is defined by a reflecting surface having at least a linear cross section lying generally in a plane aligned with or paralleling a light source and a bubble image observer (i.e. person or sensor).

Abstract: The level of a metallic bath, e.g. of an iron melt in an ingot mold, is determined by recurrent electro-optical scanning of the interior of the vessel along a narrow vertical strip zone. The output signals of the scanner are processed in an arithmetic unit which averages successive readings, to compensate for fluctuations, and may also receive a corrective signal in order to offset periodic level changes due to an intentional rocking of the vessel. The arithmetic unit may work into a visual indicator and into a controller adjusting the rate of inflow and/or withdrawal to maintain the bath level substantially constant.

Abstract: An improved apparatus suitable for detecting the outflow of a liquid such as petroleum or the like and petrochemical products from a storage tank or pipe line thereof is disclosed. The detecting apparatus comprises a detecting element including a light transmitting path made of a transparent solid material having a refractive index larger than the refractive index of water through which the light is transmitted from a light source to a light detector. If the peripheral wall surface of the light transmitting path is wetted with a liquid to be detected which has a larger refractive index than the material forming the light transmitting path, the light being transmitted through the path leaks out of the path at the wetted area of the peripheral wall surface due to the difference of the refractive index between the liquid and the path.

Abstract: An optical level detection probe is disclosed having first and second spaced apart optic guides, each guide having a 45.degree. angle reflecting face or surface opposing one another such that light traveling along the first optic guide will reflect off of its 45.degree. angle face, reflect off of the 45.degree. angle face of the second optic guide, and travel along the second optic guide for detection by a sensor as long as the material is below the reflecting surfaces. When the material reaches the reflecting surfaces, the light will be blocked.

Abstract: A liquid level monitor using the difference between the refraction of light by a prism in contact with air and by the same prism in contact with liquid being monitored to give warning of low liquid level. In preferred form for monitoring engine oil level, light is transmitted to a prism by an incoming fiber optic lead and returned from the prism by a return fiber optic lead. When the oil level is normal, the prism is in contact with the oil and the incoming light is transmitted into the oil and dissipated. When the oil level drops, the incoming light is reflected by the prism to the return lead and the reflected light is used to provide the indication of low oil level.

Abstract: A level sensing apparatus is disclosed having a source for supplying a signal having a predetermined frequency, a level sensor connected to the source and having an output for supplying an output signal having the predetermined frequency as long as the material, the level of which is being sensed, is not at a predetermined level, a frequency sensitive circuit for receiving the output signal from the level sensor and for providing an output whenever the frequency of the signal is above or below the predetermined frequency, and a load which is connected to be responsive to the output from the frequency sensitive circuit.

Abstract: A light-emitting element and a light-responsive element are optically connected with each other through a U-shaped optical guide. An output level of the light-responsive element indicates whether the U-shaped guide is above or below the liquid-level.

Abstract: Device for determining variations within an indicator tube having a material which varies in light intensity or color in the presence of particular gases, comprises a first set of light barrier devices as light sources and photoelectric cells on respective sides of the tube. A reference set of light barrier means is provided for sensing a reference value of light through the tube and is connected to a comparator for sensing the variations between it and the first set of light barrier tubes and for recording this information on a counter. The counters are connected to a time signal transmitter and time signal receiver and the predetermined variations which occur at various time intervals are picked up by an indicator or alarm circuit designed to show the variations and indications which are sensed in a particular time period.

Abstract: This invention relates to sensing in respect to fluids and utilizes an effect relating to a beam of light and a fluid boundary. It has been found that a beam of light will be modulated differently when submerged and unimmersed in a fluid and also that between these two limit positions critical levels of the beam with respect to the boundary exist in which light transmission is at a maxima and a minima. These maxima and minima can be put to use in liquid level detection and control.

Abstract: A device for indicating when the level of developer solution in an electrostatic photocopying machine falls to a predetermined level comprises a source of light and a photosensor on which the light source is focused. The photosensor generates a light intensity signal that is related in a known way to the magnitude of light incident on it. Both the light source and photosensor are mounted in a housing, which has a bottom formed to rest firmly on the bottom of the tank that holds the developer solution, and, therefore, are mounted in fixed, spaced relation relative to each other as well as to the housing bottom. A bracket, which includes a spring, supports the housing in the developer solution tank with the housing and tank bottoms in firm interengagement to establish the predetermined developer solution level equal to the distance between the tank bottom and photosensor.

Abstract: An automatically controlled liquid dispensing system including a reagent dispenser adapted to function as an intermediate container for dispensing relatively small controlled volumes of liquid to an associated receiving system in a continuous "demand" mode, this dispenser being indirectly monitored to be automatically and continually replenished after liquid is withdrawn therefrom, using a simple photoelectric liquid level monitor system including a fail-safe overflow control arrangement.

Abstract: A foam monitor senses the dissipation of foam within a transparent tube and employs a series of vertically spaced light emitting diodes which are cyclically pulsed to provide repetitive sequential scanning of the tube contents and a series of photo-responsive elements are axially spaced along the diametrically opposite side of the tube and positioned to monitor corresponding intermittent light paths that may be received from the corresponding light emitting diodes. The intermittent light paths are monitored during each scanning cycle to provide a pulse train which is indicative of the relationship between scanned levels containing foam and scanned levels void of foam. The pulses produced over a predetermined number of repetitive scans are totalized to provide an analytical measurement of the foam dissipation qualities for the liquid involved.

Abstract: In an optical detector which comprises on U-shaped transparent bar, a photoemitting diode disposed at one end of the bar and a phototransistor disposed at the other end of the bar, means for ensuring light-transmission is provided.

Abstract: Disclosed is a method and apparatus for the automated growing of a floating zone refined, monocrystalline semiconductor rod. Two images of the molten/solid interface are separately positioned on two sensor arrays which, in addition to providing positioning feedback information, measure the diameter, the length of the molten zone and the "bag" or overhang angle of the molten semiconductor matter. The output of the sensor arrays are processed into signals which operate the zone refiner controls. There is thus provided an automated process for zone refining and monocrystalline rod growth of a semiconductor crystal from a seed crystal beginning with the tapering-out process, through the straight rod growth with a closely controlled diameter portion, to the end of the tapering-in process.

Abstract: A portion of a beam of light directed towards a flow of particulate material is interrupted with an edge such that the edge casts a shadow across the material. The shadow profile is sensed and a signal indicative of the sensed shadow profile is derived and monitored as a function of flow velocity to determine the volume of flow.

Abstract: A liquid level sensor for use when filling containers with hydrocarbons or other liquids is disclosed. A fiber optic bundle is arranged to form a flow path for a light beam in such a manner that the flow path is interrupted when the liquid level reaches a predetermined part of the flow path. The fiber optic bundle can be arranged to sense the liquid level when it approaches and reaches a predetermined height and can be connected to a loading control system in order to automatically control the filling of a tank.

Abstract: In order to measure the life of the foam of an effervescent beverage a predetermined quantity of the liquid is held in an upper vessel. This liquid is then allowed to fall rapidly into a lower vessel formed of transparent material and rotated about a vertical axis. As soon as the liquid is poured violently into the lower vessel a timer is started. Simultaneously a light source directs a beam of light upwardly through the vessel and a photocell situated above the vessel receives this light. When the foam has decreased sufficiently to allow the beam to pass through to the photocell, circuitry connected between the photocell and the timer is arrested. The elapsed time is proportional to the life of the head on the beverage.

Abstract: A liquid level indicator consisting of a transparent rod within which is embedded a plurality of infrared emitters and photosensors. The infrared emitters and photosensors are mounted to a substrate which places the emitters and sensors in such a geometry as to cause total internal reflection off the transparent rod surface when an emitter-sensor pair is above the liquid level and to minimize internal reflection when an emitter-sensor pair is immersed in the liquid. The emitters are activated by electric current via conductive paths which are part of the supporting substrate. The sensors provide electric currents to an external readout device to indicate the absence or presence of liquid between emitter-sensor pairs. The liquid level indicator is made relatively insensitive to ambient light by shading the sensors from all but the desired infrared rays from the emitters. The liquid level indicator is hinged to allow a given length indicator assembly to be used in a variety of container depths.

Abstract: A small well fills with rain water and a float in the well rises to interrupt a light beam that falls on a photoelectric cell. The photoelectric cell keeps a control circuit open as long as it is exposed to the light beam and closes the control circuit in the absence of a light beam. The photoelectric cell turns on a blower to inflate a swimming pool cover and simultaneously energizes a lamp bulb to evaporate the water in the small well. When the rain ceases the lamp bulb evaporates the water in the well to lower the float and thereby stop the blower and turn off the lamp bulb. A selector switch has a normal first position to ready the rain-responsive control circuit and has a second position for energizing the blower directly when a person desires to inflate the swimming pool cover for use of the swimming pool in the absence of rain.

Abstract: A device for measuring the proportion of a first liquid in a lower refractive index second liquid with which the first liquid is immiscible, such as oil in water. An unclad optical fiber, having an index of refraction between those of the two liquids but at least equal to and not more than ten percent greater than that of the first liquid. A light energy source and detector are connected by the immersed fiber and the light energy transmission measured to determine liquid proportions.

Abstract: An optical-electrical liquid probe for sensing the presence or absence of a liquid comprises a light emitter and a light receiver housed within a translucent hollow body. When there is no liquid adjacent a sensing part of the body, the light rays from the emitter pass to the receiver by refraction through the walls of the body. The presence of liquid adjacent the sensing part of the body causes the light rays to be refracted in such a manner that they no longer reach the receiver with the result that the state of the receiver changes.

Abstract: A beam of light is directed at a flow of particulate material discharging from a conveyor in a curved path. The lower part of the light beam is interrupted by the material as it follows the curved path, the shadow profile being sensed to give an indication of the volume of material flowing.

Abstract: A device for controlling the level in a container of a liquid which will emit infra-red rays and particularly molten metal is described. The device comprises a housing, at least one longitudinal window at one end of the housing and arranged so that when in use it will overlook an edge of a container containing the liquid, the level of which is to be controlled; and at least one photo-element for sending out an electrical signal through said window to said liquid; at least one second window which is substantially punctiform and which overlooks a substantially constant portion of the liquid in the container and within the vertical field of adjustment; and a second photo-element in cooperation with the second window for sending out a pilot signal, and circuitry to correct the signal indicating the liquid level of the container by means of the pilot signal and for amplifying and comparing the signal coming from the correction circuit.

Abstract: An instrument functioning as either a turbidimeter or as a depth meter for measuring the distance from the instrument to the level of a turbid fluid. A light source provided with an optical system emits a beam of light to the fluid, and the volume or "beam of vision" viewed by a photo-cell likewise provided with an optical system intersects said beam of light. The two beams include a relatively small angle so that a tapered or conical volume of intersection in the fluid is obtained. Thus, the quantity of light scattered or reflected within this volume and reaching the photo-cell is dependent on the turbibity and the position of this level. The light emitted by the light source is modulated at a relatively high frequency. The output of the photo-cell passes through a frequency filter and is, then, indicated or recorded as a measure of turbidity or of depth of said layer.

Abstract: An optical liquid level gauge is described for sensing and indicating the height of a liquid within a container, such as within a fuel tank. The gauge includes an optical liquid probe that has a plurality of U-shaped light pipes to be inserted into a tank. Each of the light pipes terminates in a U bend with the U bends of such light pipes being staggered in position relative to one another so as to be positioned at different liquid height indication levels within the tank. A source of light is provided for transmitting light into a first arm of each of the light pipes, and sensors are provided at the end of the second arm of each of such light pipes for detecting the amount of light transmitted from one end of the pipe to the other. The U bend of each pipe has a geometrical design which assures that when liquid is not present in the tank it transmits substantially all of the light received by it from the first arm of the light pipe into the second arm thereof for sensing by the sensor associated therewith.

Abstract: A device for the outside display of the level and specific density of a liquid contained within a tank, particularly for inflammable liquids, characterized by a plurality of paired light pipes having optical interface means therebetween located at intervals within a support with electrical means operable by light energy from one of the pair of light pipes being conducted thereby due to a mismatch of the index of refraction caused by an absence of fuel at the area of the optical interface to provide a display of the fluid level and/or the density of the fluid within a tank.

Abstract: A fiberoptic fluid level sensing mechanism is provided which is operable for performing fluid level sensing as applied particularly to a mixing and dispensing device. The mechanism embodies light projecting means supported in the device so as to be positionable in juxtaposed relation to an external light source and operable to project the light rays received from the light source towards the exposed end of the fiberoptic rod. Photoelectric means is supported in juxtaposed relation to the opposite end of the shaft, and more particularly the other end of the fiberoptic bundle. In accord with the mode of operation of the mechanism, light rays from the external light source are projected through the light projecting means into the interior of the mixing chamber wherein they are operable to light the latter. As the opaque material in the chamber is dispensed, the level thereof decreases until the exposed end of the fiberoptic bundle is rendered visible.

Abstract: In a capsule filling machine, capsules held pneumatically against the periphery of a transporting disc are photoelectrically inspected by two light beams, both oblique with respect to the disc axis. Electrical gating and delay circuitry effects pneumatic removal of capsules from the disc at a location remote from the inspection location if either beam is not broken by the capsule contents.

Abstract: Apparatus for automatically controlling, by stationary optical means, the diameter of a crystal from seed to final taper in a Czochralski crystal pulling method is disclosed. The diameter control has a feed back loop including diameter sensing means which controls a motor for moving the pulled crystal up faster or slower. The diameter, at any value, is sensed by two closely adjacent photocells receiving radiation from spaced points on the solid-liquid interface and a voltage value corresponding to that diameter is developed.When a constant diameter is being maintained and the diameter increases, the magnitudes of the sensed radiation change and a difference signal voltage in one direction is generated causing the crystal pull rate to increase. When the diameter decreases the magnitudes of the sensed radiation change in the reverse and a difference signal voltage in the opposite direction is generated causing crystal pull rate to decrease.

Abstract: A digital transducer comprises a container having two disparate materials therein defining an interface, the interface being movable through the container responsive to a force, or forces, applied to one, or both, of the materials. A plurality of sensors are spaced along the container for sensing the interface, each of which is responsive to the presence of one of the materials. Means are included for suppressing the outputs of all of the sensing means responsive to the one material except that one sensing means which is responsive to the one material and nearest the interface.