Patents Represented by Attorney Timothy S. Stevens
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Patent number: 5215556Abstract: Apparatus and method for temperature gradient capillary gas chromatography wherein the chromatography column is surrounded by an inner tube and the inner tube is surrounded by an outer tube. A first heat transfer fluid is heated to a first temperature and is flowed between the inner tube and the column in the same direction as the flow of carrier gas through the capillary column. A second heat transfer fluid is heated to a second temperature and is flowed in the opposite direction between the outer tube and the inner tube, the second temperature being lower than the first temperature.Type: GrantFiled: April 15, 1992Date of Patent: June 1, 1993Assignee: The Dow Chemical CompanyInventors: Joseph F. Hiller, Glen H. Hughes, Daniel P. Martin
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Patent number: 5150601Abstract: A new use for a process gas chromatography liquid injection valve of the Bendix type, i.e., a valve having a distal heated vaporization chamber, a central sample chamber, a valve stem bore intersecting both chambers, a radially grooved valve stem positioned within the valve stem bore and an air actuator for moving the valve stem back and forth in the valve stem bore. The heated vaporization chamber is removed and is not used. Instead, a carrier gas is now flowed through the remaining chamber of the valve. The valve is mounted on a process vessel or a process conduit (and not on a gas chromatograph) so that the valve stem of the valve now can be extended from the valve and into the process liquid in the process vessel or conduit. The groove of the valve stem fills with sample and then the valve stem is retracted into the valve so that the groove is positioned within the remaining chamber, i.e., what was used as a sample chamber is now is used as a vaporization chamber.Type: GrantFiled: December 21, 1990Date of Patent: September 29, 1992Assignee: The Dow Chemical CompanyInventors: David L. Simeroth, David S. Brink, Reid S. Willis, Dale J. Backlund
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Patent number: 5151474Abstract: A process control method for controlling a polyolefin polymerization process, such as a solution polyethylene process, which includes five steps. The first step is to flow a stream of a solvent into a polyolefin reactor, such as flowing a stream of heptane solvent into the reactor at essentially a constant rate. The second step is to add a principal monomer to the stream of solvent, such as by adding ethylene at a controllable rate to the stream of solvent. The third step is to add a co-monomer to the stream of solvent, such as by adding 1-octene at a controllable rate to the stream of solvent.Type: GrantFiled: February 16, 1990Date of Patent: September 29, 1992Assignee: The Dow Chemical CompanyInventors: Sandra V. Lange, David P. Denton, Joseph P. Weller, Jean P. Chauvel, Jr., Stuart Farquharson, Harry D. Ruhl, Jr., Gregory A. Winter
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Patent number: 5136419Abstract: An improved electrochromic device of the type employing: a working electrode, such as a thin essentially transparent layer of indium/tin oxide coated on glass; the working electrode being coated with an electrochromic layer, such as a thin essentially transparent layer of tungsten oxide; the electrochromic layer being coated with an ion conducting layer, such as a thin essentially transparent layer of a perfluorosulfonate polymer; the ion conducting layer being coated with a counter electrode, such as a thin essentially transparent layer of a layer of gold. The improvement is to operate such a device in an environment of a mixture of an inert gas and the vapor of a high dielectric constant material. This can be done in a sealed double pane window by forming such a device on one of the interior surfaces of the window panes and then filling the remaining space between the panes with a mixture of nitrogen and water vapor.Type: GrantFiled: December 13, 1991Date of Patent: August 4, 1992Assignee: The Dow Chemical CompanyInventor: Mani Shabrang
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Patent number: 5134291Abstract: A method for sorting a plurality of diverse objects into groups, each such object being made predominately from at least polyethylene terephthalate and polystyrene and at least two of polyvinyl chloride, polyethylene and polypropylene, the groups consisting at least of objects of like type of polymer identified to be polyethylene terephthalate and polystyrene and at least two of polyvinyl chloride, polyethylene and polypropylene. The method includes three steps. The first step is to irradiate the objects to be sorted with near-infrared radiation. The second step is to measure the diffuse reflectance of the irradiated objects in the near-infrared region to identify the objects as to the type of polymer used to make them. The third step is to direct the objects to their respective groups according to the measurement and identification of the second step.Type: GrantFiled: April 30, 1991Date of Patent: July 28, 1992Assignee: The Dow Chemical CompanyInventors: Harry D. Ruhl, Jr., Kenneth R. Beebe
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Patent number: 5125749Abstract: A probe for in situ quantitative detection of the concentration of an analyte in a sample includes a hollow elongated body adapted for single ended contact with the sample. The body has at least one optical fiber extended through the body for transmitting modulated light through the body, out a window at the forward end of the body, and along an optical axis into the sample to optically excite the analyte. A pressure transducer mounted beyond the window and spaced laterally away from the optical axis detects an acoustic response of the analyte to the modulated light. This probe is particularly suitable for performing remote photoacoustic analysis of analyte concentration in a sample.Type: GrantFiled: September 24, 1990Date of Patent: June 30, 1992Assignee: The Dow Chemical CompanyInventors: Mary A. Leugers, Michael E. Mills
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Patent number: 5124042Abstract: A three step flow injection analysis method for determining the degree of neutralization of phenol in solution. The first step is to flow a stream of a carrier liquid, such as water, along one side of a two sided semipermeable membrane, such as a silicone rubber membrane. The second step is to flow a stream of water along the other side of the membrane to a detector, such as a flow through ultraviolet spectrometer, the detector being responsive to the concentration of the phenol in the flowing stream of water. The third step is to add a volume of the solution to the flowing stream of carrier liquid so that the solution is carried to the first side of the membrane where a portion of the phenol permeates across the membrane into the flowing stream of water to be detected by the detector, the degree of neutralization of the phenol in the solution being a function of the response of the detector. The results of the method are substantially unaffected by variations in the concentration of the phenol.Type: GrantFiled: August 1, 1991Date of Patent: June 23, 1992Assignee: The Dow Chemical CompanyInventors: Robert A. Bredeweg, Richard G. Melcher
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Patent number: 5124080Abstract: An improvement of electrochromic devices incorporating a perfluorosulfonic acid polymer ion conducting layer interposed between a working electrode and a counter electrode. The improvement relates to the composition of the perfluorosulfonic acid polymer of the ion conducting layer. In the present invention the composition of the perfluorosulfonate polymer layer is a polymer comprising a substantially fluorinated backbone which has recurring pendant groups attached thereto represented by the formula --O--(CFR'.sub.f).sub.b --(CFR.sub.f).sub.a --SO.sub.3 --, where a=0-3, b=0-3, a+b=at least 1, and R.sub.f and R'.sub.f are independently selected from the group consisting of a halogen and a substantially fluorinated alkyl group having one or more carbon atoms. One example of such a polymer is the copolymer of tetrafluoroethylene and 1,1,2,2-tetrafluoro-2-((trifluoroethenyl)oxy)ethane sulfonic acid having an equivalent weight of about 800.Type: GrantFiled: November 1, 1991Date of Patent: June 23, 1992Assignee: The Dow Chemical CompanyInventors: Mani Shabrang, Susan J. Babinec
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Patent number: 5120129Abstract: An improvement upon spectroscopic cells of the type that have a single window sealed to each window opening of the cell body. The improvement is: (1) to position an additional window at each such opening, each such window being juxtaposed, spaced apart and biplanar with each original window so that there is a sealed space between each additional window and each original window; and (2) to position at least two passageways through the body of the cell, each such passageway in fluid communication with each of the above formed sealed spaces so that any leakage of a sample past the original seal is vented from the cell via one of the passageways to a detector to be detected.Type: GrantFiled: October 15, 1990Date of Patent: June 9, 1992Assignee: The Dow Chemical CompanyInventors: Stuart Farquharson, Leslie J. May, Terry D. Haymon
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Patent number: 5077221Abstract: A chemical analysis method for indirect detection thin layer chromatography of cations that provides a rapid indication of the amount and type of cation present with minimal equipment requirements. The method includes four steps. The first step is to equilibrate a thin layer cation exchange chromatography plate with a color-forming cation, such as with copper II, to form a prepared plate. The second step is to deposit a sample on the prepared plate to form a spotted plate, the sample containing a cation of interest, such as sodium I. The third step is to develop the spotted plate with a liquid solution containing the color-forming cation, such as a solution of copper II ions, to chromatograph the cation of the sample to form a developed plate.Type: GrantFiled: July 25, 1990Date of Patent: December 31, 1991Assignee: The Dow Chemical CompanyInventors: Theodore E. Miller, Jr., Melanie C. Poon
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Patent number: 5076769Abstract: An improved double acting piston pump of the type having a shaft connected to the piston for reciprocating the piston wherein the shaft extends from the pump body. The improvement of the present invention is to reciprocate the shaft with an asymmetrical uniform motion rotary cam so that the pump delivers the same constant flow rate of a liquid being pumped during both the forward and the backward movements of the pump's piston.Type: GrantFiled: July 16, 1990Date of Patent: December 31, 1991Assignee: The Dow Chemical CompanyInventor: Jian-Dong Shao
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Patent number: 5074663Abstract: An improvement upon cylindrical MIR element cells of the type that have a single seal at the openings of the cell body through which the cylindrical MIR element extends. The improvement is: (1) to position an additional seal between each such opening and the cylindrical MIR element so that there is a sealed space between the second seal and the original seal at each such opening; and (2) to position at least two passageways through the body of the cell, each such passageway in fluid communication with each of the above formed sealed spaces so that any leakage of a sample past the original seal is vented from the cell via one of the passageways. In a highly preferred embodiment of the present invention the portion of the cell body surrounding each such opening is made demountable and is provided with additional passageways and seals so that a purge fluid can be flowed through the passageways to a flow through detector to detect any leakage of a fluid sample past one of the original seals.Type: GrantFiled: October 15, 1990Date of Patent: December 24, 1991Assignee: The Dow Chemical CompanyInventors: Richard C. Winterton, Delmar R. Lafevor
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Patent number: 5062713Abstract: A method for the on-line determination of the residence time distribution of a polymer extruder by injecting a quantity of dye, such as Mobay Red 5B, into the feed throat of the extruder and then photometrically monitoring the polymer flowing from the extruder for the dye. The advance of the present invention is to direct a single beam of polychromatic light through the polymer flowing from the extruder, e.g., by using a quartz-halogen light source and an optical fiber, and then to split this single beam of light that has passed through the polymer into two beams, e.g., by the use of a bifurcated optical fiber, each of which resulting beams are then passed through a separate filter to a separate photodetector. The wavelength of maximum transmission of one of the filters is selected to be near the wavelength of maximum light absorption of the dye so that the signal from the photodetector associated with this filter is a function of the concentration of the dye in the polymer flowing from the extruder.Type: GrantFiled: November 1, 1990Date of Patent: November 5, 1991Assignee: The Dow CompanyInventors: Stuart Farquharson, Peter T. Keillor, III
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Patent number: 5059024Abstract: An improved tristimulus sample cup of the type that generally includes an optically transparent bottom portion, a side wall portion and an open mouth. Such cups have a cavity for holding the sample, the cavity being defined by the bottom and side portions of the cup. The side wall portion has a surface which is exposed to the cavity. The improvement of the present invention relates to the optical properties of this surface of the side wall portion of the cup which is exposed to the cavity, i.e., that it have a diffuse reflectance at 580 nanometers of preferably more than eighty percent. In addition, if the sample cup is equipped with a plunger positioned in the mouth of the cup, the plunger having a surface exposed to the cavity, then the plunger surface exposed to the cavity should also have a diffuse reflectance at 580 nanometers of preferably more than eighty percent. A highly preferred cup of the present invention is made with a flat optical glass bottom, sides of white TEFLON .Type: GrantFiled: April 4, 1990Date of Patent: October 22, 1991Assignee: The Dow Chemical CompanyInventor: J. Benjamin Esquivel H.
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Patent number: 5048322Abstract: The invention describes a large volume on-column gas chromatographic method for analyzing trace levels of high molecular weight and polar compounds in a sample and an apparatus for performing the method. A column inlet coupled to an analytical column is heated rapidly to concentrate difficult to chromatograph compounds onto the analytical column resulting in an increase in the detectability of the compounds.Type: GrantFiled: September 5, 1989Date of Patent: September 17, 1991Assignee: The Dow Chemical CompanyInventors: Joseph F. Hiller, Terrence McCabe, Paul L. Morabito
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Patent number: 5046854Abstract: A photometric probe or a photometric cell having separate windows and a metallic probe body or cell body. The window(s) are sealed to the probe or cell body by brazed or frit seals which are less likely to leak after extended use in high temperature and/or high pressure industrial applications than probes and cells having gasket sealed windows. The windows can be made of sapphire, cubic zirconia, diamond, ruby, glass or quartz and, in the case of the probe, can be in the shape of an Attenuated Total Reflectance prism. The probe or cell body can be Kovar alloy or stainless steel.Type: GrantFiled: January 24, 1991Date of Patent: September 10, 1991Assignee: The Dow Chemical CompanyInventors: Joseph P. Weller, David P. Denton, Sandra V. Lange, Chester R. Norman, Mary A. Leugers, Stuart Farquharson, Jean P. Chauvel, Jr.
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Patent number: 5045284Abstract: A flow injection analysis flow cell suitable for precipitation titration flow injection analysis wherein the flow cell has a chamber and a dammed space within the chamber. The carrier containing the precipitate is flowed into the dammed space and overflows it into the chamber. The flow cell is designed so that a chemical sensing probe can be inserted into the dammed space to allow precipitation titration flow injection analysis with reduced problems of flow cell plugging.Type: GrantFiled: November 22, 1988Date of Patent: September 3, 1991Assignee: The Dow Chemical CompanyInventors: David D. Smith, Gary D. Deleo
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Patent number: 5019139Abstract: A combination of a membrane, such as a silicone rubber membrane, and a valve having a chamber within it, such as a solenoid valve. The present invention is suitable, for example, for use with a mass spectrometer. The membrane partitions the chamber into a first chamber portion and a second chamber portion. The valve has at least three passageways into it. The first two passageways lead to the first chamber portion. The third passageway leads to the second chamber portion. A solenoid plunger is used to close off the third passageway when desired. When used with a mass spectrometer, the third passageway is connected to the vacuum inlet of the mass spectrometer and a sample is flowed into and out of the first chamber portion via the first two passaageways. A component of interest in the sample can permeate across the membrane into the second chamber portion and can flow via the third passageway to the mass spectrometer. When desired, the plunger can be used to close the third passageway.Type: GrantFiled: December 22, 1989Date of Patent: May 28, 1991Assignee: The Dow Chemical CompanyInventors: Mark A. LaPack, James C. Tou
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Patent number: 5009591Abstract: A pyrolyzer for gas chromatography having a subsidiary heater and a main heater. The subsidiary heater is set below the pyrolysis temperature of the sample, e.g., at 300 degrees centigrade, to drive volatile components from the sample. The main heater is set at a pyrolysis temperature to pyrolize the sample, e.g., at 600 degrees centigrade. The sample is placed in the pyrolyzer in a sample vessel that can be positioned to be heated by main heater, the subsidiary heater and a position not heated by either the main heater or the subsidiary heater.Type: GrantFiled: January 30, 1990Date of Patent: April 23, 1991Assignee: The Dow Chemical CompanyInventor: Chuichi Watanabe
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Patent number: 5001071Abstract: A method for on-column injection of large sample volumes using the retention gap technique in capillary gas chromatography for sample components of interest that would be obscured by the large solvent peak otherwise inherent in the technique. This interference from the large solvent peak is removed by venting carrier flow from the retention gap to waste for a limited time, long enough to discard much of the solvent without serious loss of the sample component of interest.Type: GrantFiled: October 6, 1988Date of Patent: March 19, 1991Assignee: The Dow Chemical CompanyInventors: Paul L. Morabito, Joseph F. Hiller, Terrence McCabe, Thomas L. Peters