Abstract: This invention is directed to an improved total sulfur chemiluminescence detection system that uses a dual burner to generate the SO speckles for contact with ozone.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and a region for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source for ionization of a broad class of compounds.

Abstract: An ion mobility spectrometer is described for detecting sample gas in a carrier gas incorporating a block of ceramic material having a passageway wherein the passageway contains an ionization source, a resistive material on the walls of the passageway prior to and after a shutter grid to form a reaction region and drift region respectively, an aperture grid and a collector. A radioactive or non-radioactive ionization source may be inserted into one end of the passageway while the aperture grid and collector may be inserted into the other end and rigidly positioned with respect to the block of ceramic material. The invention simplifies the exchange of the ionization sources where it may be either radioactive or non-radioactive, and improves the assembling and sealing of the ion mobility spectrometer cell.

Abstract: The process comprises excavating pits at the first and second ends of a buried section of old water main pipe that is to be replaced with new pipe. The exposed segments of pipe are broken up to provide access to the bore of the old pipe. A pipe splitter and a cylinder-actuated pulling unit are installed in the first pit. A string of rods is extended through the old pipe bore from the first pit to the second pit. A tool assembly of sequentially connected components is attached to the second end of the rod string. The tool assembly may comprise: means for centralizing the second end of the rod string in the second end of the old pipe section; a pull plate for bearing against the annular second end face of the old pipe section; a cylindrical plug for expanding the passageway extending between the pits; a rod member for extending through the bore of the new pipe section to be installed; and a second pull plate for bearing against the annular second end face of the new pipe.

Abstract: A thermionic emitter for providing positive ions has been described incorporating a mixture of beta-alumina and inert material such as charcoal positioned on a filament for heating the mixture. Alternately the invention may incorporate beta-alumina with inert material such as nickle deposited in selected areas. The invention overcomes the problem of generating positive ions with low power consumption.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and means for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source and provides a means for ionization of a broad class of compounds.

Abstract: An electrochemical gas sensor is described incorporating a sensing electrode, a reference electrode, a solid matrix containing an alkali salt, a potentiostat and a heater. The invention overcomes the problem of a liquid electrolyte which may operate over limited environmental conditions.

Abstract: An ion mobility spectrometer is described for detecting gas constituents in an ambient air incorporating a cylindrical tube containing a reaction region, a shutter assembly and a drift region therein, the cylindrical tube fits within a housing having a chamber or space between the cylindrical tube and the housing for heating drift gas prior to entry into the drift region. Further, the cylindrical tube may have interior annular ledges to facilitate positioning of the shutter assembly and an aperture grid. The invention overcomes the problem of controlling the temperature of the drift gas prior to entry into the drift region to enhance the uniformity of ion drift mobility times and the problem of a mechanical assembly which is difficult to dissemble.

Abstract: A gas tight cell receives an unmetered stream of sample gas. The cell is divided into a reaction chamber, as drift chamber and an ion collector chamber by transverse shutter grids normally carrying an ion repellent charge. The inlet of a chromatograph analytical column is connected to the outlet of the cell ion collector chamber. Inert gas admitted to the ion collector chamber is divided into a drift gas stream and into an oppositely directed carrier gas stream. The drift gas flows from the collector chamber through the drift chamber and out the reaction chamber. The carrier gas flows from the collector chamber through a deionizer into the chromatograph column. An electrostatic field urges sample gas ions from the reaction chamber toward the ion collection chamber. The ions are blocked from entering or exiting from the intervening drift chamber by the charge on the shutter grids.

Abstract: An electrochemical gas sensor is described for detecting a gas constituent, for example hydrazine in a gas ambient incorporating an electrochemical cell including a reference electrode, counter electrode and sensing electrode spaced apart and with an electrolyte in contact with each electrode and comprising n-methyl-2-pyrrolidone and a salt soluble therein, for example tetraalkyl ammonium salt. The invention overcomes the problem of specificity, service life and operating temperature range associated with aqueous electrochemical gas sensors.

Abstract: An enzymatic toxic gas sensor 10 having a plurality of parallel planar surfaces and a buffered electrolyte reservoir 44. The buffered electrolyte is conveyed by means of diffusion to a substrate 28 to dissolve the substrate. The substrate diffuses to an immobilized enzyme where it is hydrolyzed if the enzyme is active. An electrochemical cell continuously monitors the hydrolyzed substrate concentration which is an indication of the enzymatic activity and presence of toxic gas. A circuit means responds to the current output of the electrochemical cell to indicate the presence or absence of a toxic gas. The shelf life of the sensor is extended by means of a separator for maintaining the enzyme dry and inactive. The enzyme in the preferred embodiment is acetylcholinesterase (AcHe).

Abstract: An electrochemical gas detection cell, particularly suitable for detecting H.sub.2 S, includes an electrochemical gas sensor which has a reference electrode, a sensing electrode and a counter electrode. The counter electrode is composed of carbon. The sensing electrode is composed of either gold or platinum and the reference electrode is composed of platinum. Circuitry is provided to supply voltage to the electrodes, the sensing electrode bias can be held below 300 mv., with respect to the reference electrode. The agent H.sub.2 S can be readily detected when the bias is about 250 mv. The cell is associated with signal processing circuitry which produce audible and visual outputs. A nonaqueous electrolyte is provided. The electrolyte may be composed of either propylene carbonate or n-methyl-2-pyrrolidone and one of conductive compatible salts, such as tetrabutyl ammonium tetrafluoroborate.

Abstract: An electrochemical detection cell which includes, in the order named, a stack of components constituted by a first membrane, an electrode carrier having reference and counter electrodes thereon, a membrane support, an electrode carrier having a sensing electrode thereon, and a permselective membrane. Whatman filter papers are positioned between the sensing electrode and both the counter electrode and reference electrode, these being positionable in a central rectangular opening of the membrane support. The cell allows air or gas ambient to address the membranes and effects application of an electrolyte to space between the electrodes by, for example, a wick which extends between an electrolyte-containing reservoir and the Whatman filter papers. A system for detecting a gaseous agent uses the aforementioned detection cell coupled with circuitry capable of applying a fixed DC voltage bias to the reference electrode and superimposing a train of DC voltage pulses on the fixed bias.

Abstract: An ion mobility detector in which selectivity and sensitivity is enhanced by converting through surface interactions sample gas or vapor to a form more readily ionized or by converting through surface interactions interferent gas or vapor to a form less readily ionized. To accomplish the conversion, samples may be passed through a catalytically reactive filter prior to injection into the detector reaction region; exposed to a reactive coating placed on the surface of a permeable membrane prior to diffusion therethrough into the reaction region or exposed to a reactive coating placed on the interior walls of the reaction region.