Abstract: An optical transducer for determining liquid level within a container includes a sensing probe having a first elongate measurement face and a second elongate measurement face that converges toward the first measurement face. A light source is positioned for directing radiant energy into the sensing probe and a photosensor is positioned for detecting an amount of radiant energy exiting the sensing probe. With this arrangement, a change in the amount of radiant energy as detected by the photosensor is indicative of a change in liquid level within the container.

Abstract: A content detecting apparatus uses a signal from a light-receiving part receiving light projected from a light emitting part to detect ink in an ink cartridge. The light-emitting part and the light-receiving part are arranged with differing optical axes. The ink cartridge has reflecting parts for reflecting projected light from the light-emitting part so the projected light reaches the light-receiving part when remaining content is present when the ink cartridge is properly set and with an inclined interface located in a path along which projected light from the light-emitting part reaches the light-receiving part, for switching between permeation and reflection according to the presence and/or absence of remaining content. The inclined interface is permeated along the path with projected light form the light-emitting part when remaining content is present and reflects projected light from the light-emitting part out of the path when remaining content is absent.

Abstract: Arrays of optical fibers connected to specially configured electronics, e.g., a phototransistor, an LED, an amplifier, a detector, and display, software and PCMCIA A/D board available on a personal computer, are used to obtain continuous real-time acquisition, processing, and visualization of change in a media occurring in natural environments. Alternatively, many of the individual circuit elements above may be replaced with a power meter. In a specific application, data are collected on the depth of sediment below a body of water. As the sediment depth is changed by an event, the ends of the optical fibers in the array display a different reflection or transmission coefficient indicating that water has replaced sediment or vice versa. By knowing which of the optical fiber ends in the array is indicating the changed reflection or transmission coefficient, scour depth or silt accretion may be estimated. A method of employment of the system is also described.

Abstract: An oil tank sight glass monitor comprising a housing having an opening therein sized to receive the sight glass of an oil tank; an emitter for emitting a beam of light, the emitter being mounted to the housing on one side of the opening so that the beam of light is directed across the opening; a detector for detecting the beam of light generated by the emitter, the detector being mounted to the housing on the other side of the opening, in optical alignment with the emitter, so as to detect the beam of light emitted by the emitter; and an alarm for producing an audible sound when the detector fails to detect the beam of light generated by the emitter.

Abstract: In order to improve a method to determine the lubricant filling degree of a fluid bearing in which the bearing gap of the fluid bearing is illuminated and the luminous reflectance is analyzed so that the filling degree can be determined in a simple and reproducible manner, it is provided that a spatial intensity profile of the reflected light is recorded.

Abstract: A fluid reservoir sensing system includes a pair of optical prisms or sensor targets that reflect light when a fluid level is below one of the pair of prisms or sensor targets. The pair of optical prisms or sensor targets includes a low prism or sensor target usable to sense a low liquid level in the fluid reservoir, and a high prism or sensor target usable to sense a high liquid level in the fluid reservoir, and a wicking means to wick fluid away from the high incident and low incident surfaces of the prisms or sensor targets that are above the fluid level. The fluid reservoir sensing system optionally includes an emitter and a photosensor.

Abstract: A liquid container for containing liquid incldes a reflection member provided in a liquid containing portion and having a plurality of roof mirror assemblies arranged in a predetermined direction, each of the roof mirror assemblies having at least two reflecting surfaces positioned with a predetermined angle therebetween; wherein the reflection member is effective to divide incident light, which is scattering light, into a plurality of light beams by the plurality of roof mirror assemblies and to condense at a predetermined position the beams sequentially reflected by the at least two reflecting surfaces of the roof mirror assemblies, and wherein an amount of the liquid in the liquid container is detected on the basis of the light reflected by the reflection member.

Abstract: An Laser Airborne Depth Sounder (LADS) system for the measurement of water depth is disclosed, the system includes a transmitter and a receiver of laser light having at least two wavelengths so as to receive a first reflection from a water surface and a second reflection from a water bottom an a rotating mirror which directs the laser light to the water and receives the second reflection of the laser light from the water bottom and directs the second reflection to the receiver, where the receiver includes an optical shutter (76) adapted for selectively allowing the passage of the second reflection laser light therethrough. The shutter (76) may include a LCD matrix or mechanical light blocking elements. The LCD matrix may be arranged in a central circle (82), an inner ring (80), and an outer ring (78).

Abstract: An inexpensive, optical position sensor for measuring a position or length, x, along a one-dimensional curvilinear, coordinate system. The sensor can be used, for example, to determine the position of an interface between a clear and an opaque fluid (such as crude oil and water). In one embodiment, the sensor utilizes the principle of dual-fluorescence, where a primary fiber emits primary fluorescent light and a parallel secondary fiber collects a portion of the primary fluorescent light that is not blocked by the opaque fluid. This, in turn, excites secondary fluorescence in the secondary fiber at a longer wavelength. A light detector measures the intensity of secondary fluorescence emitted from an end of the secondary fiber, which is used to calculate the unknown position or length, x. Side-emitting fibers can be used in place of, or in addition to, fluorescent fibers. The all-optical sensor is attractive for applications involving flammable liquids.

Abstract: An optical sensor (5) for recording wetting of a surface (20) of a member (21), especially a window of a motor vehicle, having a transmitter (13), a receiver (14) and a retroreflector (11, 11?, 11?) for electromagnetic waves is proposed. The surface (20) of the member (21) has for this at least two sensing regions (12, 12?), which are exposed to electromagnetic waves originating from the transmitter (13) and coupled into the member (21) in a central region (10), the development of wetting on the sensing regions (12, 12?) effecting a change of the signal of the electromagnetic waves coupled out into the receiver (14) in the central region (10). For this, the retroreflector (11, 11?, 11?) is developed and positioned in such a way that it feeds back electromagnetic waves reflected by the surface (20) of the member (21) to the surface (20) of the member (21), and from there into the central region (10).

Abstract: The invention relates to a method to optically measure the filling level of a liquid in a cavity having a sub-mm wide opening with the aid of a measuring sensor based on chromatic coding, the measuring sensor delivering a distance value and an intensity value as its output signal. The method is characterized by the steps: Recording a distance profile and an intensity profile of the surface of the liquid by moving the measuring sensor along the opening of the cavity holding the liquid, the movement being made essentially parallel to the surface of the fluid along a measurement segment x, and determining the filling level by means of a combined analysis of the recorded distance profile and intensity profile.

Abstract: A non-mechanical fluid level sensor based on light communication channel (LCC) technology. In a preferred embodiment, one end of the LCC is connected to a signal source while another end is connected to a sensor. The LCC is dipped in a fluid container and a signal propagates and undergoes internal reflection through the LCC towards one of its ends which is connected to the sensor. The fluid level is detected preferably by measuring the intensity of the signal reflected with the LCC that reaches a sensor. Different fluid levels preferably correspond to linearly varying detected signal intensities. A main LCC bus may communicate remotely with the sensor without wiring or other electrical connectors.

Abstract: A level detector comprises an array of light emitting devices mounted in a line parallel to an array of light receiving devices, the arrays being mounted within a housing capable of internally reflecting light from the emitting devices to respective receiving devices unless the respective parts of the level sensor are immersed in liquid. The outer internally-reflecting surface of the housing is preferable a continuous straight-line surface along the direction parallel to the arrays.

Abstract: In a method of optically determining a level of liquid in a liquid-filled container a light guide body projects into the container. The light guide body has an end face for the entry and exit of light and stepped side faces forming separate reflection faces. The light is totally reflected at those reflection faces which are not immersed in the liquid but refracted into the liquid at immersed reflection faces. The totally reflected light is reflected back to the end face. The intensity of the light beam reflected totally by each reflection face back to the end face is measured separately. Measurement signals for determining the filling level are subjected to plausibility checking to recognise and eliminate measurement faults and errors. The invention can be used for determining the level of liquid in a container or tank for fuel, washing water, oil, hydraulic fluid and the like in a motor vehicle.

Abstract: A level control system for controlling the thickness of a work material in a slurry form cast upon a moving belt includes a fluid reservoir disposed above the belt, a sensor lens assembly for sensing the slurry height within such reservoir, and a control valve for adding slurry to the reservoir. A lens disposed near the moving belt and above the reservoir is coupled by fiber optics to a remote sensor amplifier for detecting the height of the slurry. A control circuit responsive to the light sensor regulates the flow rate of the slurry through the control valve.

Abstract: A fiber optic sensor for monitoring point temperature of in situ reactions in remote, based on the principle of guiding light by means of total internal reflection (TIR) occurring in a right-angled prism, mounted on a glass capillary tube comprises isopropyl alcohol in it and rises due to increase in temperature and touches the prism surface thereby preventing the occurrence of TIR thus reducing the level of output optical signal detected.

Abstract: A preferred embodiment of a system for measuring a level of a fluid comprises a light source adapted to generate light having a predetermined wavelength, an optical waveguide slab at least partially filled with a material adapted to fluoresce when illuminated by the light having a predetermined wavelength, and a light pipe. The light pipe is adapted to transmit the light having a predetermined wavelength to the optical waveguide slab at an angle that causes the light to be internally reflected only within a portion of the optical waveguide slab located above the fluid thereby illuminating the fluorescent material within the portion of the optical waveguide slab located above the fluid. The preferred embodiment also comprises a photo-multiplier tube adapted to generate an electrical output in response to the fluorescence of the fluorescent material.

Abstract: The present invention aims at attaining a liquid surface level detecting apparatus, which can be used in various detection targets and usage environments without selecting a detection target, can efficiently irradiate a light to a liquid surface level detecting unit and detect a variation in a light reception amount of a light receiving means at a high sensibility, and can be excellent in durability, easy to manufacture, and be actually used. By placing a light shielding means 14 so as not to directly irradiate the light from a light emitting means 12 to a light receiving means 13, the light from the light emitting means is scattered by an optically scattering means 16, and a part of that scattering light is radiated to an outside by the liquid surface level detecting unit on a light radiating means (an optically transmitting member) 11.

Abstract: An apparatus for handling liquids and including a lighting installation for lighting an approximately punctiform illumination point in the room, an approximately punctiform light-receiving device having a photodetector for providing a measuring signal dependent on the intensity of the light received, an imaging system for imaging the illumination point onto the approximately punctiform light-receiving device, and an evaluation device for detecting the approaching of an interface between two media of different refractive indices to the illumination point by evaluating the measuring signals provided by the photodetector.

Abstract: A fiber optic liquid level detector uses optical fibers to detect the presence or absence of liquids. The waveguide properties of optical fibers tends to deviate from the normal dielectric interfaces so that a fiber immersed in a liquid has a reflection coefficient smaller than when surrounded by air. This is caused by the differences in refractive indices of liquid and air and is used to measure the amount of light transmitted or reflected by the fiber in the preserve or absence of a liquid.

Abstract: A liquid-level sensor is used to sense th level of a liquid. The sensor has at least two solid optical conductors, wherein each solid optical conductor includes an outer surface having at least one reflective surface discontinuity of sufficient size to interfere with a total internal reflection of the solid optical conductor when the reflective surface discontinuity does not contact the liquid. A support positions the reflective surface discontinuities at a different height above the boom of the volume. A light source introduces light into a first end of each of the solid optical conductors. A light detector structure receives light that has been introduced into each of the solid optical conductors and has traveled through the respective solid optical conductor at least as far as at least one of the reflective surface discontinuities of the respective solid optical conductor.

Abstract: A specimen sensing apparatus according to the present invention includes a specimen container which is vertically positioned by a container holder of a columnar rack type and conveyed by a belt conveyor, an infrared CCD camera configured to pick up an infrared image of the specimen container, a visible image converter which converts the infrared image picked up by the infrared CCD camera into a visible image, an image signal processing unit which processes and converts one of the infrared image and the visible image into a signal that is suitable to measure a specimen amount, and a specimen amount measuring unit which measures an amount of specimen contained in the specimen container in response to the signal processed by the image signal processing unit.

Abstract: An ink jet recording apparatus comprises a carriage movable in a given direction with a recording head which is detachably mountable on it and provided with discharge ports for discharging liquid. The apparatus is arranged to include a sensor for detecting the presence or absence of the carriage, the recording head, and at least one of the ink containers. This sensor is provided for the main body of the apparatus and positioned within the movable range of the carriage. With this arrangement, it is possible to simplify the structure required for detecting whether or not these vital elements for recording are installed without any auxiliary power-supply or memory means.

Abstract: For measurement of a liquid level, an optical fiber connected at its one end portion to force receiving means movably arranged in liquid to receive force from the liquid is dipped in the liquid together with the force receiving means, and a change in the force acting on said force receiving means when the liquid level changes is detected as a change in strain in the optical fiber by means of an optical fiber strain gauge connected to the other end of the optical fiber, thus measuring a water level of the liquid.

Abstract: A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.

Abstract: The invention relates to refractometry and attenuated reflectance spectrometry in a wellbore environment. Specifically, it pertains to a robust apparatus and method for measuring refractive index of fluids along a continuum (rather than in steps), and for measuring attenuated reflectance spectra, and for interpreting the measurements made with this apparatus to determine a variety of formation fluid parameters. The present invention provides a method and apparatus to distinguish between gas and liquid based on the much lower index of refraction of gas. It can also be used to monitor fluid sample clean up over time. The refractive index of a wellbore fluid is determined from the fraction, R, of light reflected off the interface between a transparent window that has a known refractive index and this fluid. Preferably, the refractive index is measured at some wavelength of light for which the fluid is not highly attenuating.

Abstract: A continuous measurement of the level of contents in a container is effected by a level measuring device functionong in accordance with the transit time principle by means of waves transmitted from a position located above the highest possible contents level onto the surface of the material in the container. A measuring circuit determines the contents level from the transit time of the useful echo reflected from the material surface. In addition, one or more limit sensors are located at the container, each of which furnishes a signal indicating whether the contents level is above or below a level to be monitored by the limit sensor and which is situated between the minimum and maximum contents levels of the container. The measuring circuit receives the output signals of all limit sensors and uses these output signals to check and eventually to correct the contents level measured value determined by the level measuring device.

Abstract: A safe and reliable aircraft fuel gauging system which eliminates the need for electrical wiring to transmit electrical signals into and out of the fuel tank of an aircraft. The fuel gauging system utilizes at least one light source to generate input light signals which are delivered to a plurality of probes multiplexed on a fiber optic element. The same, or a separate, fiber optic element transmits the probes' output light signals to a light detector located externally of the fuel tank. Each probe includes a photoelectric conversion device, an LC resonant circuit, and a magnetooptic device for generating the responsive output light signal to the input light signal. Based on the output signal form the probes, the light detector determines the level of fuel in the tank.

Abstract: An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered facets, which are angled surfaces located on the outer periphery of the waveguide. When the fuel level within the fuel tank is above a particular tiered facet, light that impinges that facet will refract out of the waveguide, conversely, when the fuel level is below that facet, impinging light will be reflected back into the waveguide such that it is received by the photo receiver. In this manner, the fuel level sensor is able to utilize the reflected light received by the photo receiver to provide an electronic signal representative of the fuel level. Furthermore, a calibration feature may be included which provides calibration information indicating when the fuel level has reached a known, predetermined level.

Abstract: An optically based liquid level (liquid-vapor) detector for use with a window having a substantially planar side facing the liquid-vapor side and a substantially planar side positioned parallel to the liquid-vapor side facing the outside. The detector comprises a light source positioned on the outside of the window to direct its light through the outside planar side to the inside planar liquid-vapor side and a light detector positioned on the outside of the window to receive light transmitted from the source and returned from the planar liquid-vapor window side. The detector further includes electronic means for detecting the light intensity change affecting the transducer, from the condition of liquid on the liquid-vapor side, to the condition of vapor on the liquid-vapor side of the window, whereby an action or signal is generated in response to such change.

Abstract: A device and method for performing a preliminary test on a neat serum sample contained in a primary collection tube is provided herein. The method includes the steps of positioning of an optical probe near the primary collection tube and monitoring the neat serum sample in the primary collection tube to determine whether an interferant, such as hemolysis, icteris and lipemia are present in the serum sample. From this test, a hemolytic index, an icteric index and a lipemic index can also be established for the neat serum sample. Based upon these serum indices, the neat serum sample can be transferred to a clinical analyzer for additional testing or to waste receptacle because the sample is compromised. Additionally, a volume test can be performed on the serum sample in the primary collection tube so that the serum sample can be properly allocated during subsequent testing.

Abstract: An apparatus and method for measuring the viscosity of Newtonian and non-Newtonian fluids over a range of shear rates, especially low shear rates, by monitoring two rising columns of fluid (Newtonian or non-Newtonian) that pass through respective capillaries having different lengths. Furthermore, a specialized column monitor is provided that uses multiple interrogation sources (e.g., lasers) and a single detector (e.g., a charge-coupled device (CCD) array) to continuously monitor both columns of fluid substantially simultaneously. In particular, the system includes a Y-connector to form two flow paths and wherein each flow path includes a tube that includes a riser tube, a capillary tube of predetermined dimensions and a valve in each for controlling the fluid flow in each path.

Abstract: A method for controlling a molten metal pouring operation is disclosed which works in the presence of unusual pouring conditions such as typically encountered in aluminum casting and utilizes a laser type sensor, for example a triangulation based light section device, to monitor differences between a reference surface and the molten metal in a mold.

Abstract: In a method of optically determining a level of liquid in a liquid-filled container a light guide body projects into the container. The light guide body has an end face for the entry and exit of light and stepped side faces forming separate reflection faces. The light is totally reflected at those reflection faces which are not immersed in the liquid but refracted into the liquid at immersed reflection faces. The totally reflected light is reflected back to the end face. The intensity of the light beam reflected totally by each reflection face back to the end face is measured separately. Measurement signals for determining the filling level are subjected to plausibility checking to recognise and eliminate measurement faults and errors. The invention can be used for determining the level of liquid in a container or tank for fuel, washing water, oil, hydraulic fluid and the like in a motor vehicle.

Abstract: A method and system are provided for determining the level of a body of water, whether free flowing or stationary. Positionable mirrors are located at an area adjacent to but spaced from the body of water. The mirrors direct a laser beam at an angle to true vertical onto the surface of the body of water such that a portion of the beam is reflected from the surface. A receiver is located at a known distance from the mirrors on the opposite side of the body of water and in a common horizontal plane. The receiver receives a reflected laser beam and redirects the beam to a signal detector. A controller for the mirrors determines the angle to true vertical at which the mirrors are set after receiving an output from the signal detector. A simple calculation, based on the determined angle and the known distance between the mirrors and the receiver is then made of the distance from the common horizontal plane to the water surface so as to determine the water level.

Abstract: A melt level or the gap between a melt surface and a heat shield is measured accurately irrespective of how the melt surface is. A laser beam (2) from a range-finding unit (8) is reflected by a scanning mirror (24) and projected on a melt surface (3) through an entrance window (18) and a quartz prism (20) in a chamber (17) of a puller. After specular reflection, the beam forms a measurement spot (31) in the bottom of a heat shield (16) and scatters. Part of the scatter, after specular reflection at the melt surface (3) (secondary reflection), passes through the prism (20), the entrance window (18) and the scanning mirror (24) to the range-finding unit (8). The range-finding unit (8) carries out triangulation using the distance between a laser source and a photodetector therein, and the angle of incidence and the angle of the received laser beam.

Abstract: An opto-electric levelmeter having a sensor that provides an output signal whose frequency represents the surface level of liquid in a container. The sensor's circuitry includes an oscillation circuit that uses “optical feedback” to modulate the sensor output signal. The signal is delivered to a monitor that provides an output signal for the user. The monitor also permits adjustment for both high and low levels of a particular container. The monitor sends electrical energy to the sensor, and receives the sensor output signal on the same electrical link.

Abstract: The invention describes a method and a device for determining a filling level and can be applied to the ascertainment of the simmering process of mineral oil products. The method is characterized that by means of at least two stationary sensors, a first filling level and at least a second filling level are defined and the number of drops required for reaching the first and second filling levels is recorded. By way of a further sensor the number of drops dropped in during the simmering process is counted and, by way of calculation, the partial volume at a specified location and the filling level are determined.

Abstract: A system is provided for registration of a fluid level of a fluid in the fluid chamber of an invention-specific receptacle (1), in particular of ink in an ink cartridge, with a light source (11) which beams into the chamber of the receptacle, a reflection body (2) which is designed as a float, which moves in the chamber of the receptacle in dependency upon the filling level of the fluid and which variably reflects the light in dependency upon its movement, and a light detector (10) which receives a variable amount of light.

Abstract: An optically-based overfill detection probe is provided that has a prism made of a fluoropolymer, preferably TEFLON® PFA. The prism material has a high resistance to chemical solvents, is less prone to condensation and frost than plastic or glass, and enables the production of prisms at significantly less cost than glass. The probe also includes a two-piece housing structure that compresses an outwardly-extending portion of the prism material to firmly hold the prism in place, and forces the material into sealing contact with an inner surface of the housing. The housing has an elongate portion that encompasses the prism, and which extends toward the fluid, preventing any light which escapes the prism from being externally reflected back to the photodetector of the probe.

Abstract: A non-mechanical fluid level sensor based on light communication channel (LCC) technology. In a preferred embodiment, one end of the LCC is connected to a signal source while another end is connected to a sensor. The LCC is dipped in a fluid container and a signal propagates and undergoes internal reflection through the LCC towards one of its ends which is connected to the sensor. The fluid level is detected preferably by measuring the intensity of the signal reflected with the LCC that reaches a sensor. Different fluid levels preferably correspond to linearly varying detected signal intensities. A main LCC bus may communicate remotely with the sensor without wiring or other electrical connectors.

Abstract: A method and system are provided for determining the level of a body of water, whether free flowing or stationary. A rotatable reflective element is located at an area adjacent to the body of water. The reflective element is driven by a rotating motor shaft and includes a reflective surface extending 45° to the shaft axis. Rotation of the reflective surface provides scanning of a laser beam directed axially thereon. During scanning, the beam is directed at an angle to true vertical onto the surface of the body of water such that a portion of the beam is reflected from the surface. A detector array, located on the opposite side of the body of water and in a common horizontal plane with the reflective element, produces an output after receiving the reflected beam. A controller arrangement, including a counter which begins counting when-the scanned beam is vertical and which stops counting when a signal corresponding to the array output is received, determines the scan angle to true vertical.

Abstract: A system for returning residual liquid remaining in a loading line to a liquid cargo container after loading or unloading of the cargo container. This system includes a liquid return line extending between the loading line and the cargo container. A pump is positioned to move liquid from the loading line, through the liquid return line, and into the cargo container. A vapor line communicates between a vapor space in the cargo container and the loading line. The system may include an optical liquid level sensor. The level sensor includes a light tube having two substantially straight sections joined by a substantially continuous curvature bend. The bend has a rounded cross-section and the light pipe is formed of a light conducting material. An optical emitter is positioned at the end of one of the straight sections of the pipe and an optical detector is positioned at the other straight section of the pipe. A micro-controller activates the optical emitter and monitors the optical sensor.

Abstract: Method and apparatus for measuring the liquid fill level in bottles while the bottles are still within the turret section of the filler system. A source of focused light, such as that generated by a laser, is directed onto a series of targets positioned on the turret behind the bottles. The beam is directed back through the bottle neck and detected by a remote camera.

Abstract: An opto-acoustic wave sensor provides for the detection, the determination of the location, and/or the quantification of an amount of a chemical species using a selective chemical interaction of the chemical species and a selective reagent disposed on a surface of the opto-acoustic wave sensing element. The amount of the chemical species is detected by a change in the mass of the opto-acoustic wave-sensing element, which results in a detectable change in a resonance frequency of the sensing element. The identity of the chemical species is ascertained by an optical property of the product of the selective chemical interaction such as an absorbance or an intensity or other properties of the electromagnetic radiation emitted by the product.

Abstract: The invention is a rain sensor including a transmitter and receiver formed by chips bonded onto a printed circuit board. Advantageous embodiments of the invention provide filtering of radiation guided to the receiver of the sensor. The sensor is provided with a barrier to suppress parasitic radiation.

Abstract: An optically-based overfill detection probe is provided that has a prism made of a fluoropolymer, preferably TEFLON® PFA. The prism material has a high resistance to chemical solvents, is less prone to condensation and frost than plastic or glass, and enables the production of prisms at significantly less cost than glass. The probe also includes a two-piece housing structure that compresses an outwardly-extending portion of the prism material to firmly hold the prism in place, and forces the material into sealing contact with an inner surface of the housing. The housing has an elongate portion that encompasses the prism, and which extends toward the fluid, preventing any light which escapes the prism from being externally reflected back to the photodetector of the probe.

Abstract: An apparatus for indicating a fluid level in a reservoir includes a conduit for communication with a reservoir and including a sight glass. A buoyant primary float is provided within the conduit, and a stop is provided within the conduit for engaging the primary float to prevent travel of the primary float beyond an upper portion of the conduit. A buoyant secondary float in the conduit is moveable together with the primary float when the primary float is not engaged by the stop, and is moveable separately from the primary float when the primary float is engaged by the stop and a fluid level in the conduit exceeds the level of the stop such that a portion of the secondary float may travel separately within the upper portion of the conduit. The secondary float preferable includes an elongate portion that passes through an aperture in the primary float, and a buoyant upper portion that is located above the primary float and is larger than the aperture in the primary float.

Abstract: A method, a device, and a test kit for performing this method for determining the volume of a sample of the liquid. In the method, a specific concentration of a chromophoric indicator is provided in this liquid, a sample is separated from the liquid, the optical absorption of the separated sample is measured, and the volume of the separated sample is determined by correlation of the measured optical absorption with the concentration of indicator in this liquid. Ions that generate a color in the sample by complexing with a specific ligand are used as the indicator to stain the liquid.

Abstract: An apparatus for measuring the level of liquid contained in a tank includes a tank, at least one exhaust pipe having a transparent portion, a light source for emitting light to the transparent portion of the at least one exhaust pipe, a photodetector for detecting light reflected by or transmitted through the transparent portion of the at least one exhaust pipe and outputting electric signals corresponding to the detected light, and a liquid level measuring portion for measuring the level of liquid contained in the tank from the electric signals output from the photodetector. The transparent portion of the at least one exhaust pipe has one end thereof installed to be connected to the tank and the other end, horizontally extended a predetermined length from the one end, connected to a set supply path and/or the tank so that liquid can be collected.