Abstract: The invention concerns a method of monitoring flow in a flow pipe. According to the invention, the method comprising the following steps: providing a flow pipeline having a unique photon detector at a first position on the periphery of said pipe, a first photon source at a second position on the periphery of of said pipe, said detector and first source defining a first chord across said pipe, and one or more additional photon sources at positions on the periphery of said pipe defining one or more additional chords across said pipe; determining the density across said first chord from the count rate detected from the first source by the detector; and determining the densities across said one or more additional chords from the count rate detected from the one or more additional sources by the detector in order to determine the deposition of solid in the pipe.

Abstract: The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples.

Abstract: A UV absorption spectrometer includes a housing, a controller, and a sensor unit including an ultraviolet light source, an analytical area in an analytical cell or in running water or gaseous medium, and an UV wavelength separator including a UV detector. An ultraviolet light in a wavelength range of 200-320 nm emits from the light source through the analytical area to the wavelength separator, and the controller transforms output signals from the UV detector into absorbance values or optical densities for two or more wavelengths in the wavelength range, calculates differences of said absorbance values or optical densities, determines a concentration of a chemical in the solution with calibration constants found for a known concentration of the chemical and said differences of said absorbance values or optical densities.

Abstract: An improved elemental mercury analyzer utilizes a fluorescence assembly in combination with a fluorescence quenching reduction mechanism to detect the concentration of elemental mercury within an emission gas sample, via fluorescence of the mercury within the gas sample, while minimizing fluorescence quenching of the gas sample. In one arrangement, the analyzer contains the emission gas sample under a vacuum or negative pressure while detecting fluorescence of the elemental mercury within the emission gas sample. By performing fluorescence detection of the emission gas sample at reduced pressure relative to the pressure of the as-sampled emission gas, the analyzer reduces the number of particle collisions within the emission gas sample over a certain period of time. Such collisional deactivation, and/or the addition of oxygen depleted gas such as nitrogen to the gas sample, reduces fluorescence quenching of the emission gas sample, improving accuracy of detection of mercury.

Abstract: A device for detecting impurities in a noble gas includes a detection chamber and a source of pulsed ultraviolet light. The pulse of the ultraviolet light is transferred into the detection chamber and onto a photocathode, thereby emitting a cloud of free electrons into the noble gas within the detection chamber. The cloud of electrons is attracted to the opposite end of the detection chamber by a high positive voltage potential at that end and focused onto a sensing anode. If there are impurities in the noble gas, some or all of the electrons within the cloud will bond with the impurity molecules and not reach the sensing anode. Therefore, measuring a lower signal at the sensing anode indicates a higher level of impurities while sensing a higher signal indicates fewer impurities. Impurities in the range of one part per billion can be measured by this device.

Abstract: A device for photometric measurement of the concentration of a chemical substance in a solution, including: a lamp, which emits electromagnetic radiation in a predetermined wavelength range; a first receiving unit in a measuring branch (MB), which receives the radiation transmitted through the solution at a first wavelength; a second receiving unit in a reference branch (RB), which receives the radiation transmitted through the solution at a second wavelength; and a control/evaluation unit, which, depending on the conditions present at the measuring site, uses the intensity values determined either by the measurement branch (MB) or by the reference branch (RB), in order to control the intensity of the radiation emitted by the lamp, such that the resulting, measured values are highly plausible.

Abstract: A photoelectrocatalytic sensor system for measuring oxidizable impurities in air. The sensor system may include a transistor having an electrode and a channel for the flow of current, a photocatalytic material coated onto the electrode of the transistor, a light source for producing an ultraviolet light beam onto the photocatalytic material, and a sensor for measuring the flow of current.

Abstract: A gaseous target analyte present as a minor constituent in an admixture with at least one other gaseous species can be detected using a cavity enhanced optical spectrometer by a process comprising the steps of: i) identifying a plurality of strong spectral absorption peaks of the target analyte which are present within the scanning range of the spectrometer, ii) determining for the identified peaks the pressure region above which the peak width increases substantially with increasing pressure and below which the peak width is substantially independent of pressure, iii) determining which of the peaks identified in step i) are, within the pressure region determined in step ii), free from spectral interference by any of the other components of the admixture. iv) measuring the spectrum of the admixture at the pressure region identified in step ii).

Abstract: An optical gas-detecting device for measuring a concentration of a gas to be measured includes a light source for radiating ultraviolet rays, a detecting element for detecting the radiated ultraviolet rays, and a light path, through which the radiated ultraviolet rays pass from the light source to the detecting element. The gas to be measured is introduced into the light path and absorbs a part of the radiated ultraviolet rays with an absorption band. The detecting element detects an absorption rate of the gas so as to measure the concentration of the gas.

Abstract: The invention relates to a sample cell with a glass body comprising a gas inlet and a gas outlet and at least one orifice, a plane glass window is fused into the orifice, the shape and size of the window corresponds to the shape and size of the orifice, the orifice is limited by a rim, the rim is wider than the thickness of the window, the rim of the window is fused with the rim of the orifice. The invention further relates to a method of producing the sample cell. The window is inserted into the orifice. The rim of the orifice is heated several times from the exterior in such a way that the glass melts and a fused joint is formed between the window and the rim of the orifice. The sample cell produced by the method has a particularly rigid joint between the window and the glass body. Therefore, this glass cell is able to withstand pressures above 10 bar and allows the passage of light without lens effects owing to its plane-parallel windows. The sample cell is used in a polarizer for inert gas.

Abstract: A measuring apparatus for measuring a spectrum of extreme ultraviolet light that diverges from a divergent center point of an extreme ultraviolet light source, includes a spectrum measuring unit that includes a spectrometer and a detector that has a spatial resolution in a spectrum forming direction of the spectrometer, and a drive mechanism that makes the spectrum measuring unit movable relative to the divergent center point.

Abstract: A chopped radiation source composed of a radiation source component, a chopping component and an optical fiber connector component. Each of these components is arranged within a housing in a manner such that the elements of each of these components will not move in an unintended manner during use.

Abstract: An inline air handler system and associated method of use is disclosed. This includes a member, at least one sensor operatively attached to the member, at least one ultraviolet light operatively attached to the member, at least one electronic input device, at least one electronic output device, a control unit, which includes a processor, that is electronically in communication with the at least one sensor, the at least one ultraviolet light, the at least one electronic input device and the at least one electronic output device, a water purification mechanism that includes an ultraviolet radiation chamber to allow water to flow between the inlet and the outlet through the ultraviolet radiation chamber and the ultraviolet radiation chamber can be positioned adjacent to at least one ultraviolet light. The air filtration unit and the member are positioned in a chamber located within a heating, ventilation, evaporative cooling and/or air conditioning system.

Abstract: The present invention is directed to a method for determining the concentration of hydrogen peroxide in a chemical process stream which may include interfering components. Still further, this invention is directed to a method and apparatus for the on-line, automated determination and control of hydrogen peroxide in a process stream.

Abstract: In a method for monitoring of polymer in a liquid state, such as a polymer melt or resin, to detect inhomogeneities therein, such as the presence of other phase objects, especially gels in a matrix formed of the liquid state, the polymer in a liquid state flowing past an inspection point is monitored. At the inspection point, electromagnetic radiation in the form of UV light or polarised electromagnetic radiation is passed through the flow chamber (1) and received by a detector (8), and the absorption of the UV light or the changes in the state of polarisation of the electromagnetic radiation caused by the inhomogeneities are used to observe them.

Abstract: A fluorescence detecting device is configured so that a semiconductor integrated circuit substrate includes a photodiode and a signal detecting circuit for detecting charges obtained as a result of photoelectric conversion by the photodiode, and a fluorescence reaction vessel where a fluorescence reaction occurs is arranged above the foregoing photodiode. Furthermore, in the device, an excitation-light-entry preventing layer is provided at one or more of a surface portion of the photodiode and a position between the photodiode and the fluorescence reaction vessel.

Abstract: A nitric oxide sensor and method is disclosed. The sensor is based on sum-frequency mixing of a tunable, 395-nm external cavity diode laser with a 532-nm diode-pumped intracavity-frequency-doubled Nd:YAG laser in a beta-barium-borate crystal. The output from the BBO crystal is ultraviolet radiation at 227 nm and is split using a 50—50 beam splitter. Half of the radiation is directed into a reference photomultiplier tube, and the other half of the UV radiation is directed through the medium of interest and then directed into a signal photomultiplier tube. The output from the photomultiplier tubes is compared and the difference utilized to indicate the level of nitric oxide by absorption-based spectrosocpic techniques.

Abstract: The present invention is directed to a method for determining the concentration of hydrogen peroxide in a chemical process stream which may include interfering components. Still further, this invention is directed to a method and apparatus for the on-line, automated determination and control of hydrogen peroxide in a process stream.

Abstract: A monitor is provided for use in measuring the concentration of hexavalent chromium in a liquid, such as water. The monitor includes a sample cell, a light source, and a photodetector. The sample cell is in the form of a liquid-core waveguide, the sample cell defining an interior core and acting as a receiver for the liquid to be analyzed, the interior surface of the sample cell having a refractive index of less than 1.33. The light source is in communication with a first end of the sample cell for emitting radiation having a wavelength of about and between 350 to 390 nm into the interior core of the waveguide. The photodetector is in communication with a second end of the waveguide for measuring the absorption of the radiation emitted by the light source by the liquid in the sample cell. The monitor may also include a processor electronically coupled to the photodetector for receipt of an absorption signal to determine the concentration of hexavalent chromium in the liquid.

Abstract: An apparatus for monitoring the condition of a lubricating medium includes a UV light source, a UV receiver, a processor electrically coupled to both the UV light source and the UV receiver, and a memory device electrically coupled to the processor. The memory device has stored therein a plurality of instructions which, when executed by the processor, cause the processor to (a) communicate with the UV light source and the UV receiver so as to expose a sample of the lubricating medium to the UV light and generate a UV spectrum of the sample in response thereto, and (b) compare the UV spectrum of the sample to a model spectrum and generate a control signal if the UV spectrum of the sample has a predetermined relationship to the model spectrum.

Abstract: A fluorescence detecting device is configured so that a semiconductor integrated circuit substrate includes a photodiode and a signal detecting circuit for detecting charges obtained as a result of photoelectric conversion by the photodiode, and a fluorescence reaction vessel where a fluorescence reaction occurs is arranged above the foregoing photodiode. Furthermore, in the device, an excitation-light-entry preventing layer is provided at one or more of a surface portion of the photodiode and a position between the photodiode and the fluorescence reaction vessel.

Abstract: Concentration of a solute in a solution is determined. Light from a light source is received at a chamber containing the solute and the solution. The light is transmitted along an optical path length of the chamber, through the solute and the solution, and output from the chamber. The light output from the chamber is detected by a detector. The optical path length of the chamber is selected to optimize sensitivity of the detector. The concentration of the solute in the solution is determined based on the light received by the detector.

Abstract: The invention relates to a new method for determination of realistic UV protection factors or bread spectrum indices of a sunscreen preparation. Realistic UV protection factors are calculable by determination of the theoretical and the experimental UV absorbances of known UV filters in wavelength steps of about 5 nm in the range of 290-400 nm from a definite basic formulation (emulsion, gel etc.) and on a transparent substrate and introducing of the values in a mathematical model. These factors are in conformity with values measured in vivo. The number of the experiments for developing new formulations are significant reduced because only basic formulation, kind and concentration of the filters have to enter.

Abstract: It is often desirable to operate ultraviolet (UV) water treatment systems at high fluid velocities; such as, when low UV doses are required, the UV transmittance of the water being treated is high, or when a high intensity radiation source is used. The operation of an open channel UV fluid treatment system at high fluid velocity causes a disproportionate amount of water to pass through the relatively low intensity region above the top lamp. This results in non-uniform UV dose delivery and poor reactor performance. In one embodiment of the invention, by elevating the inlet to the irradiation zone of the fluid treatment system with respect to the outlet, the amount of water that passes above the top lamp can be minimized, improving overall system performance. The means of elevation can consist of a step or slope in the channel, or a combination of both. Depending on the magnitude of elevation, an increase in maximum velocity of approximately two times can be obtained.

Abstract: A transmission meter (1) and a method for measuring the transmittance of a fluid, the meter (1) comprises an analysis chamber for passage of the fluid therethrough, means for receiving an electromagnetic source (9) within said chamber and three sensors (D1, D2 and D3) each configured to measure the output from said source (9), wherein each of the three sensors (D1, D2 and D3) are located at different distances from the source (9). The transmission meter may be used in a disinfection system either to measure the transmittance of the untreated water or to measure the transmittance of the water as it is purified.

Abstract: The invention features an optical medium for calibrating UV absorbance detectors, methods for making such an optical medium, and methods for calibrating UV absorbance detectors using such a medium. The optical calibration medium includes a gel-sol silica glass monolith with a rare-earth dopant therein. The rare-earth dopant exhibits at least one spectral feature in at least the far UV range. The constituents of the gel-sol silica glass monolith are selected so the rare-earth doped sol-gel glass monolith exhibits a transmittance in the far UV range so each distinct spectral feature of the rare-earth dopant in the far UV range is discernable. The transmittance in a particular embodiment is at least about 50% at about 250 nm. The rare earth materials selected for use as dopants are those exhibiting a wide range of spectral features, preferably over a range from about 190 nm to about 700 nm and more particularly exhibit at least one distinct spectral feature in the range from about 190 nm to about 300 nm.

Abstract: An optical instrument includes an optical element and a detector for detecting an impurity concentration in an ambience containing a space surrounding the optical element. By controlling the impurity concentration on the basis of an output of the detector, deposition of impurities on the optical element and deterioration of the optical characteristic of the optical element thereby can be prevented effectively.

Abstract: In a method for monitoring of polymer in a liquid state, such as a polymer melt or resin, to detect inhomogeneities therein, such as the presence of other phase objects, especially gels in a matrix formed of the liquid state, the polymer in a liquid state flowing past an inspection point is monitored. At the inspection point, electromagnetic radiation in the form of UV light or polarised electromagnetic radiation is passed through the flow chamber (1) and received by a detector (8), and the absorption of the UV light or the changes in the state of polarisation of the electromagnetic radiation caused by the inhomogeneities are used to observe them.

Abstract: An ultraviolet light radiation photodetector includes a quartz lens, a UV transmission filter, a silicon photodiode, and a scintillator layer. After passing through the quartz lens and the UV transmission filter, the UV light to be detected is converted in the scintillator layer, preferably applied to the surface on a light-exiting side of the UV transmission filter, into light radiation of a greater wavelength, for which the silicon photodiode exhibits a greater sensitivity. If desired, an additional edge filter can be used to improve the configuration's drop in sensitivity between 350 and 400 nm.

Abstract: The invention relates to a method and a measurement device for measuring a suspension which contains wood fibers, the method comprising directing optical radiation at pulp and measuring optical radiation emitted by the pulp. The solution comprises measuring at least one of the following two properties; kappa number and brightness. The solution comprises changing the pulp consistency in a desired range of consistency extending from a desired initial consistency to a desired final consistency. The pulp consistency and the strength of a desired wavelength from the optical radiation are measured in the desired consistency range. Measurement points are modeled with a function of the desired type by fitting the parameters of the function according to the measurement points. Finally at least one of the following two properties of the pulp is determined by means of the modeling function; kappa number and brightness.

Abstract: A monitor is provided for use in measuring the concentration of hexavalent chromium in a liquid, such as water. The monitor includes a sample cell, a light source, and a photodetector. The sample cell is in the form of a liquid-core waveguide, the sample cell defining an interior core and acting as a receiver for the liquid to be analyzed, the interior surface of the sample cell having a refractive index of less than 1.33. The light source is in communication with a first end of the sample cell for emitting radiation having a wavelength of about and between 350 to 390 nm into the interior core of the waveguide. The photodetector is in communication with a second end of the waveguide for measuring the absorption of the radiation emitted by the light source by the liquid in the sample cell. The monitor may also include a processor electronically coupled to the photodetector for receipt of an absorption signal to determine the concentration of hexavalent chromium in the liquid.

Abstract: A multiple-channel spectrometer assembly for analyzing a plurality of sample flows. The assembly includes a plurality of spectrometer channels, each fluidly connectable to a respective one of the sample flows. Each channel has a sample inlet and a sample outlet connectable to a respective one of the sample flows. Each channel has a chassis and a light source mounted to the chassis. A spectrometer module is adjacent to each chassis and is optically coupled a light outlet portion of the light source. The spectrometer module has an optical inlet axially coupled to the light outlet portion to receive light from the light source. A high-pressure flow cell assembly is positioned adjacent to the chassis between the light source and the spectrometer module to emulate a fiber optic cable therebetween. The flow cell assembly has a flow passageway in fluid communication with the sample inlet and sample outlet.

Abstract: An on-line halogen analyzer system and method of use for semiconductor processing effluent monitoring. The system includes sampling the effluent stream into an absorption cell, and passing UV-Visible light through the effluent sample in the cell. After passing through the sample the light is collected by a photo detector for real-time wavelength-selective absorption analysis. The system provides simultaneous determination of the concentrations of multiple halogen gases (e.g. F2, Cl2, Br2, and I2) in semiconductor processing effluent streams. The invention can be used for chemical vapor deposition (CVD) chamber cleaning endpoint determination and to improve fluorine utilization efficiency in remote plasma downstream CVD chamber cleaning processes.

Abstract: A method for distinguishing between biomolecule and non-biomolecule crystals. The method comprises providing electromagnetic radiation to a sample comprising a crystal, allowing the electromagnetic radiation to interact with components of the crystal, and detecting effected changes, if any, in the quantity or character of the electromagnetic radiation, whereby a biomolecule crystal is capable of being distinguished from a non-biomolecule crystal. A device adapted for distinguishing between biomolecule and non-biomolecule crystals comprises a sample support, a source for a type of electromagnetic radiation, wherein the electromagnetic radiation can be provided to the sample, and a detector for the electromagnetic radiation wherein changes in the quantity or character of the electromagnetic radiation can be detected. The device can comprise more than one source of electromagnetic radiation for providing more than one type of radiation.

Abstract: An optical gas sensor has a compact design and without movable optical elements, with at least one radiation source (8), at least one measuring detector (9, 12) and a reference detector (11). The reflecting measuring cuvette is designed as an annular space (1) between a first, inner cylinder section (6) and a second, outer cylinder section (2) that is concentric thereto. The annular space (1) is limited by a cover element (5) and a bottom element (7) arranged at a spaced location therefrom in the direction of the longitudinal axis. The cover element (5) is permeable to the measuring gas. The bottom element (7) accommodates the radiation source (8).

Abstract: An on-line halogen analyzer system and method of use for semiconductor processing effluent monitoring. The system includes sampling the effluent stream into an absorption cell, and passing UV-Visible light through the effluent sample in the cell. After passing through the sample the light is collected by a photo detector for real-time wavelength-selective absorption analysis. The system provides simultaneous determination of the concentrations of multiple halogen gases (e.g. F2, Cl2, Br2, and I2) in semiconductor processing effluent streams. The invention can be used for chemical vapor deposition (CVD) chamber cleaning endpoint determination and to improve fluorine utilization efficiency in remote plasma downstream CVD chamber cleaning processes.

Abstract: A light source arrangement for conducting spectroscopic analysis of a material to be analyzed has a first source of electromagnetic energy for issuing a first source electromagnetic energy having a first predetermined spectroscopic characteristic and a second source of electromagnetic energy for issuing a second source electromagnetic energy having a second predetermined spectroscopic characteristic. The light source arrangement is provided with a first port for emitting an output electromagnetic energy having an output spectral characteristic responsive to a selectable combination of the first and second predetermined spectroscopic characteristics. A holder secures the material to be analyzed in a first path of propagation of the output electromagnetic energy. A third port emits a first test electromagnetic energy having a first test spectral characteristic responsive to an interaction between the output electromagnetic energy and the material to be analyzed.

Abstract: The invention relates to a method and a measurement device for measuring a suspension which contains wood fibers, the method comprising directing optical radiation at pulp and measuring optical radiation emitted by the pulp. The solution comprises measuring at least one of the following two properties: kappa number and brightness. The solution comprises changing the pulp consistency in a desired range of consistency extending from a desired initial consistency to a desired final consistency. The pulp consistency and the strength of a desired wavelength from the optical radiation are measured in the desired consistency range. Measurement points are modeled with a function of the desired type by fitting the parameters of the function according to the measurement points. Finally at least one of the following two properties of the pulp is determined by means of the modeling function: kappa number and brightness.

Abstract: An optical radiation sensor device includes a radiation collector for receiving radiation from a predefined arc around the collector within the field and redirecting the received radiation along a predefined pathway; motive means to move the radiation collector from a first position in which a first portion of the predefined arc is received by the radiation collector and a second position in which a second portion of the predefined arc is received by the radiation collector; and a sensor element capable of detecting and responding to incident radiation along the pathway when the radiation collector is in the first position and in the second. The use of the optical radiation sensor device in a radiation source module and in a fluid treatment system is also described.

Abstract: A flame scanner for effecting therewith individual burner flame discrimination in multi-fossil fuel fired steam generators. The subject flame scanner is based on the use therein of a silicon carbide photodiode that is operative for converting into a photocurrent ultraviolet light, which impinges upon the silicon carbide photodiode after passing through a focusing lens.

Abstract: An ultraviolet radiation water treatment device for a water cooler machine having an ultraviolet lamp housed inside a transparent inner sleeve which is itself disposed inside an outer transparent sleeve. The upper ends of the two sleeves are housed in a short pipe having a peripheral flange which abuts the sides of the cooler's water tank. A water inlet tube enters the top of the tank and passes between the two sleeves to feed water proximate the tank bottom to circulate the influent water up between the two sleeves and down outside the outer sleeve into the reservoir water to accomplish three exposure passes to the bactericidal ultraviolet radiation.

Abstract: A device for light intensity measurement of the electromagnetic radiation from a UV lamp in a container including light guides and respective photodetectors. The light guides comprise two dosed light guides arranged in parallel with the lamp, preferably in the entire length, and two differently dosed edge glass filters enclosing each of the light guides, while a photodetector is positioned at one end of each of the light guides. The device allows measurement of predefined wavelengths of emitted electromagnetic radiation along the entire lamp. The device relates to a reaction container with UV lamps and intensity sensor, adapted for disinfection or photochemical treatment of flowing water.

Abstract: The invention relates to an apparatus for the photo-initiated chemical cross-linking of material (28). To form one or more mouldings the material is enclosed in an optically transparent mould (26). The apparatus has at least one light source (12), for example a pulsed UV light source by which the material (28) can be acted upon by a light that triggers the cross-linking. The region to be cross-linked in the mould (26) is determined at least partially by beam-delimiting elements (20, 22) between the light source (12) and the mould (26). That can be achieved by arranging between the light source (12) and the mould (26) a mask (20) having transparent and non-transparent surface portions. The mask (20) is then projected onto the material (28) that is enclosed in the mould (26) by projection optics (24). The projection of the mask (20) onto the material is effected in a telecentric beam path.

Abstract: An ultraviolet light detector for detecting levels of ultraviolet light in a liquid disinfection unit comprises two solid state silicon photodetectors. A first photodetector generates a photo-induced current proportional to the amount of visible, infra-red, and ultraviolet light emitted. A second photodetector generates a photo-induced current proportional to the amount of visible and infrared light emitted. The photodetectors are electrically connected in reverse parallel, generation an output current equal to the difference between the photo-induced currents of the photodetectors. The output current is thus proportional to the UV light intensity. The output current may be converted into a voltage, which may be monitored to ensure that the ultraviolet light intensity is sufficient for complete disinfection of the liquid. An electronic control system may be provided so that the output voltage controls a solenoid valve and/or an alarm in the disinfection unit.

Abstract: A measurement method and a measurement apparatus for measuring the structure of a micro-structure or the structure along the depth of an object for measurement. The laser light from a solid-state laser light source is subjected to wavelength conversion to generate the ultraviolet laser light, and measurement is made of the object for measurement by heterodyne detection or homodyne detection employing the ultraviolet laser light. This enables measurement of a structure of a micro-structure. Alternatively, the laser light is split into multiple laser light beams and frequency shifted so that the laser light beams will be of different frequencies. The laser light beams are imaged at respective different focal point positions to perform heterodyne detection. The resulting heterodyne signals are separated into respective frequency bands and measurement is made of the structure of the object for measurement in association with the respective imaging points.

Abstract: A device for determining the level of UV-transmission through a flowing media This UV-transmission is determined by measuring and evaluating the radiation intensity of a UV-radiation source radiating through a zone of the medium. The emitting surface of the UV-radiation source partly extends into the flowing medium and partly into a reference space, or borders on the medium and the space. Two UV-sensors are directed at zones of equal irradiation intensity of the radiation source emitting surface. In this case, the one UV-sensor is arranged in the flowing medium and the other UV-sensor in the reference space. Both UV-sensors are connected to a measuring and evaluating circuit, which compares and evaluates the signals of the UV-sensors.

Abstract: A UV detector for liquid chromatography is equipped with a light source; a flow cell having a light entrance side and a light exit side; a first optical system for shining light from the light source into the flow cell so as to form an image roughly at the light exit side of the flow cell or at a position outside the flow cell at a prescribed distance away from the light exit side thereof; a light detector; a second optical system for directing light exiting the flow cell to the light detector; and a truncated cone shaped sample chamber formed in the flow cell along the axial direction thereof, with the base of the truncated cone being positioned at the light entrance side of the flow cell.

Abstract: A method and apparatus are provided for collecting a sample gaseous mercury, to differentiate between different gaseous mercury components. A quartz denuder module is provided having a coated extended surface for adsorbing reactive gaseous mercury. After collection of a sample, the coating it is heated to desorb the mercury as elemental gaseous mercury, which can then be detected and measured in conventional analyzer. During the sampling phase, as reactive gaseous mercury is removed from the sample flow in the denuder, the sample can then be passed to the analyzer for detection of elemental gaseous mercury. Where particulate mercury may be present, a filter trap can be provided downstream from the denuder. Separate steps can be provided for heating and pyrolysis of particulate mercury, for separate measurement in the analyzer. The pump module can be configured to a past the gas sample through scrubbers, to generate zero air as a flushing gas.

Abstract: An improved apparatus and method for measuring the concentration of hydrogen peroxide vapor or gas in a sterilization chamber. The hydrogen peroxide is measured spectrophotometrically in the ultraviolet region between 200 and 400 nm. Because water vapor does not absorb in the ultraviolet region, it does not interfere with the determination of the concentration of the hydrogen peroxide vapor. Although organic compounds have absorbances in the ultraviolet region, the organic compounds are removed by evacuating the sterilization chamber to low levels before doing the hydrogen peroxide determination. The ultraviolet light source is either a low pressure mercury vapor lamp with an emission at 254 nm or a deuterium lamp with an optical filter selective of 206 nm light. A movable gas cell can be used to measure the hydrogen peroxide concentration at various areas in the sterilization chamber.

Abstract: A method and apparatus are for characterizing colloids by successive measurements of light attenuation or emission of a colloidal mixture at two or more temperatures and at one or more wavelengths. The difference or ratio of the measurements at two or more temperatures provides a measure of the colloidal stability with respect to temperature. The amount of certain organic colloids that are unstable to temperature variation may be determined from the magnitude of the measurement change. In appropriate mixtures, this method provides a means to distinguish components of colloidal substances based. This method may be specifically applied to determining the stability and concentration of colloidal pitch or wood resin in a pulp or paper process water. In this context it may be used to distinguishing colloidal pitch or wood resin from talc, clay, carbon black, or other fillers.