General Signal Corporation

Leeds & Northrup Company

Microtrac Inc.

Honeywell G.m.b.h.

Other

Paul J Freud

Ronald D Baxter

Michael N Trainer

Paul M Kroninger, Jr

Giancarlo Punis

Clarissa G Jakob

Glenn W Dixon

Anthony M Demark

Dean P Updike

A zeta potential measurement system comprising: a cell having a cell wall and bottom for holding suspended particles; an optical measurement probe having a probe tip comprising a transparent and conducting thin film coating which prevents ionic current from accumulating charge on the probe tip, and wherein the optical measurement probe is inserted through the cell wall such that the probe tip is in fluid communication with the sample; a counter electrode inserted through the cell wall opposite to the optical measurement probe; a laser source which is disposed so as to deliver light to the optical measurement probe via an optical directional coupler and optical waveguide; wherein the optical measurement probe focuses the light onto a front surface of the probe tip, such that the light reflected from the front surface of the optical measurement probe and light backscattered from particles in the sample are collected by the probe tip, and thereafter focused to a optical waveguide and delivered through the coupler to a photodetector; an electrical output of the photodetector is connected to a filtering and amplification module, wherein an analog output of the amplification module is connected to an analog-to-digital converter, wherein the analog-to-digital converter creates a digital data stream which is stored in a first memory; and a computer or microprocessor which calculates the frequency power spectrum from the stored digital data stream and stores the frequency power spectrum in a second memory, wherein the first and second memories can be either the same or different.

Method and apparatus for measuring zeta potential of suspended particles

An adjustable focusing assembly for use with an optical probe includes a focusing element having a first and a second end mounted within a holder member. The holder member is secured to the optical probe with the focusing element optically coupled to the light images projecting from the light probe. A window having an inner and an outer surface is mounted on a body member with the window inner surface in a facing and spaced relationship to the focusing element second end. The body member further includes a cowled portion extending from the periphery of the body member on a side opposite the window, arranged to engage surfaces on the periphery of the holder member, thereby defining a cavity between the focusing element second end and the window inner surface. The body member is adjusted, increasing or alternatively decreasing the cavity until the light images from the focusing element second end are focused on the window outer surface. Upon establishment of the focus, the cowled portion is fixed to the holder member, fixing the focusing assembly to the optical probe. A second embodiment is also disclosed that alternatively locates the focusing element against the window inner surface forming the adjustable cavity between the focusing element and the optical probe. The body member is adjusted increasing or alternatively decreasing the cavity until the light images from the focusing element second end are focused on the window outer surface.

Optical waveguide probe having variable gap focusing

A device is disclosed that creates and delivers diluted representative samples of a processed medium, flowing as a process stream in a conduit, for the analysis by a particle measurement instrument. The device includes an extraction conduit that includes a probe end extending into the process stream. The probe end includes a pitot-like opening adapted to receive therein a portion of the processed medium. A diluent delivery conduit is housed substantially within and in coaxial alignment with the extraction conduit, forming a sample delivery passage therebetween. The diluent delivery conduit is arranged to emit a stream of diluent into the processed medium entering the probe end creating diluted representative samples of the processed medium. The diluted representative samples flow through the sample delivery passage to a sampling chamber of the particle measurement instrument, where they are analyzed.

In-line diluting extractor

A system is disclosed for the extraction and delivery of a diluted representative sample of a processed medium, flowing as a process stream in a conduit, for the analysis by a particle measurement instrument. The system includes a shroud tube located within the conduit, longitudinally aligned with the process stream and arranged to receive and allow a portion of the process stream to flow therethrough. A diluent delivery apparatus includes an emitter that is located in the shroud tube arranged to release a stream of diluent into the shroud tube. The diluent released by the emitter mixes with the processed medium within the shroud tube. A sample recirculation apparatus is connected to the particle measurement instrument and includes a collector located in the shroud tube downstream from the emitter and a drain located in the conduit downstream of the collector. The collector captures representative samples of the diluted processed medium flowing past the collector and conveys, on a continual basis, the captured samples to the particle measurement instrument for analysis. The representative samples displaced by the newly arriving samples are conveyed to the drain and returned to the process stream flowing in the conduit. The flow of the diluent from the emitter can be adjusted by manipulating a flow control device. The flow control device can be adjusted manually or automatically by the controlling output of a controller responsive to output signals from the particle measurement instrument.

System for the in-line extraction and dilution of a representative

A system is disclosed for the extraction of a representative sample of a processed medium, flowing in a process stream under a first pressure force, and the delivery of the extracted representative sample to a mixing chamber along with a diluent medium. The system includes a source of a second pressure force connected to the mixing chamber, the second pressure force having a value less than the first pressure force of the process stream. An extraction flow control device connects the mixing chamber to the process stream and is operable into a first or alternatively a second position. When operated in the first position the second pressure force of the mixing chamber is connected to the first pressure force of the process stream and, responsive to the pressure force difference, a portion of the processed medium is drawn from the process stream through the extraction flow control device. A source of diluent medium under a third pressure force is further included connected to the extraction flow control device. The third pressure force also has a value greater than the second pressure force. Operating the extraction flow control device into the second position isolates the first pressure force of the process stream from the second pressure force and connects the second pressure force to the third pressure force of the source of diluent medium. Responsive to the pressure force difference between the third pressure force and the second pressure force, diluent medium flows from the source of diluent medium through the extraction flow control device to the mixing chamber, carrying with it the representative sample of processed medium previously extracted.

Sampling and diluting system for particle size distribution measurement

A low power apparatus for measuring various process parameters and/or physical properties of a fluid or gas medium by measuring the change of a wave signal or time dependent signal as it traverses the fluid or gas medium, the apparatus comprising: at least one transmission transducer for providing a transmitted wave or time dependent signal for injection into the fluid or gas medium; at least one reception transducer, displaced from the transmission transducer for receiving a received wave or time dependent signal from the fluid or gas medium; and an analog signal processor, coupled to the reception transducer, for processing of the received wave or time dependent signal such that a short interval of the processed received wave or time dependent signal is extracted.

Low power signal processing and measurement apparatus

A dynamic light scattering analyzer which comprises: a sample cell which comprises a cell housing and a cell chamber, the cell chamber being formed within the cell housing such that the cell chamber is exposed to a membrane which is capable of retaining within the cell chamber the particles of a sample introduced into the cell chamber while allowing a liquid carrier to diffuse across the membrane in and out of the cell chamber; a light source; an optical waveguide which is capable of exposing the particles to a light source and which is capable of receiving the light scattered from the particles within the cell chamber and the light reflected from the waveguide-solution interface; a photodetector which is capable of detecting the light scattered from the particles within the cell chamber and the light reflected from the waveguide-solution interface; and a pump for controlling the flow rate and concentration of the carrier liquid which contacts the membrane.

Dynamic light scattering microvolume cell assembly for continuous flow

A Doppler velocimeter for measuring the doppler frequency shift of light scattered from particles suspended in a medium. The velocimeter includes a light source and an integrated optical waveguide having a first optical waveguide path for receiving an incident beam of light from the light source at one end. The first waveguide path further guides the incident beam to a second end which is located in the medium adjacent the particles. A second optical waveguide path is optically coupled to the first waveguide path for receiving the scattered light from the particles as well as the non-scattered light and guiding both to the other end thereof. A detector receives the scattered and non-scattered light from the second waveguide and converts it to an electrical signal indicative of the doppler frequency shift.

Integrated optical waveguide doppler velocimeter

A differential pressure transducer assembly for measuring flow in dirty and solids bearing fluids utilizes small barrier diaphragms located at the pressure taps of a flow measuring restriction. The barrier diaphragms are of minimum size and minimum thickness with a minimum volumetric compliance and are connected to a pressure receiving body by equal length capillaries of minimum i.d. A measuring transducer with a diaphragm having low volumetric displacement for measured differential pressures and having minimum volume diaphragm cavities is connected to the capillaries by equal and minimum volume cavities in the pressure receiving body. The pressure receiving body cavities on both the high pressure side and the low pressure side incorporate close tolerance inserts of material having a low thermal expansion coefficient when compared to that of the pressure receiving body, so that with increases in temperature the volumes of the cavities, which are minimized as much as possible, will increase just enough to match the increase in volume of the fill fluid which fills the cavities and capillaries.

Remote probe differential pressure transducer

The structure consists of a substrate, a set of interdigitated electrodes deposited on the substrate surface. The electrode fingers have a period less than the substrate thickness. A first water permeable polymer film is deposited over the electrodes and a conductive mesh is formed over the first polymer film. A second polymer film is deposited over the mesh burying the mesh between the two polymer films. The spacing between openings of the mesh is less than the thickness of the second polymer film. The square of the sum of the two polymer film thicknesses is minimized so that the response time is minimized. The mesh conductivity is made greater than a minimum value so that the resistive component of the impedance is small compared with the capacitive impedance, and thus the device impedance is independent of any instabilities in the conductive mesh impedance.

Humidity sensing element

A capacitive pressure transducer whose diaphragm is formed of single crystal, highly doped silicon by etching in opposite sides the recesses which define the deflecting region of the diaphragm. This deflecting region serves as one electrode of the transducer. Two support plates of silicon are anodically bonded to opposite sides of the diaphragm along its periphery using thin layers of borosilicate glass to form with the etched recesses pressure receiving cavities. These thin layers of borosilicate glass are interposed between the diaphragm and a support plate, and extend over the entire surface of the support plate facing the diaphragm to provide for electrical isolation as well as the bonding between the diaphragm and the support plates. These layers of glass are made as thin as possible consistent with the need to maintain the stray capacitance below a certain value. The transducer is mounted to a pressure receiving assembly by using a silicon stub having a passage for communicating one pressure to be measured to the transducer. The stub is joined at one end to the transducer by anodic bonding using a thin layer of borosilicate glass. A weldable tube is attached to the stub. This tube is long with respect to the stub and has a reduced diameter at one end which fits into the passage of the stub. The reduced diameter is kept at a minimum. The tube is welded to the pressure receiving body at its end to provide mechanical isolation for the transducer.

Pressure transducer and mounting

A thin film resistance thermometer is manufactured to have a predetermined temperature coefficient of resistance while minimizing the amount of metal in the film. The process involves the production of a metal film deposit on an insulating substrate such that the film deposited has a bulk coefficient substantially higher than the desired coefficient with the film being deposited to a thickness that produces the desired coefficient.

Thin film resistance thermometer with a predetermined temperature

A humidity sensing element of the capacitance sensing type having two sets of interdigitated fingers of thin film platinum deposited on a glass substrate, all covered by a coating of water absorbing material such as cellulose acetate butyrate or a silicone rubber. The coating is of thickness such that it is substantially equal to or greater than the period of the fingers of the interdigitated electrodes.

A capacitive pressure transducer utilizing a plate of electrically conductive semi-conductor material sandwiched between a pair of plates of inorganic electrically insulating material and electrostatically bonded thereto. A pair of concentric circular recesses are etched in the plates in such a way as to form cavities on opposing sides of the conductive plate and to define a diaphragm area on that plate. Apertures are drilled through the insulating plates to expose the cavities to the pressures to be measured. The surfaces of the insulating plates in the cavities have deposited on them electrically conductive surfaces which form capacitors with the diaphragm area on the conductive plate. A stress relief area is provided on the high pressure side surrounding the diaphragm area. In that stress relief area, the conductive plate is unrestrained by the adjacent insulating plate. Provision of this stress relief makes it possible to extend the pressure range of the transducer beyond the range which would normally be useful for the dimensions of the particular transducer.

Silicon diaphragm capacitive pressure transducer

A plurality of recesses and interconnecting paths are etched into the surface of a silicon wafer. A plate of borosilicate glass carrying thin-film metal deposits in a corresponding pattern is electrostatically bonded to the silicon to form a multiple-cavity variable capacitance pressure transducer.

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Furlong, PA, United States of America

Paul J Freud