Abstract: A flame ionization detector comprises a housing forming a flame chamber for burning a mixture of hydrogen, oxidant and a sample gas. The flame chamber includes: a nozzle in which the sample gas and hydrogen are intimately mixed prior to injection, an igniter for igniting the gas emitted from the nozzle, inlets for hydrogen and oxidant, and an exhaust outlet through which the burnt gases are removed. A collector electrode is electrically insulated from the housing of the flame chamber. The nozzle and flame chamber housing are electrically grounded, and the collector electrode is maintained at a predetermined potential relative to ground. A pre-chamber is disposed adjacent to the flame chamber to provide a substantially constant pressure input of the sample gas to the nozzle.

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: The objects of the invention are attained in an apparatus for performing a method of analysis of organic compounds in chromatography, comprising a chromatographic column sealingly connected with the housing of a surface ionization detector having coaxially arranged inside, a collector and a thermoemitter with current leads, the housing of the surface ionization detector being provided with an opening for an auxiliary gas feed line and an opening for delivering the spent gases. The thermoemitter includes a closed-end sleeve with a heating element in contact with the external non-working surface of the thermoemitter. The collector includes a hollow cylinder spaced from the inner ionizing surface of the thermoemitter, and the outlet portion of the chromatographic column being received inside and throughout the length of the collector.

Abstract: A detector system (10) especially suited for detecting a halogen containing component in a gas stream includes a gas chromatograph (12), which is connected by gas line (13) to pyrolysis chamber (14). Sources (16) of additional gas streams are connected by a gas line (18) to the pyrolysis chamber (14). The detector electrodes in the pyrolysis chamber (14) are electrically connected to detector electronics (20) by line (22). A temperature control circuit (24) is electrically connected to heater (26) by line (28). Heater (26) is thermally coupled to the pyrolysis chamber (b 14) at (30). The pyrolysis chamber (14) is thermally coupled to thermocouple (32) at (34). The thermocouple (32) is electrically connected to the temperature control circuit (24) by line (36). The heater (26) is independent of the detector electrodes and maintains a temperature between about 700 degrees and 1000 degrees Centigrade. The detector electrodes are substantially alkali metal free.

Abstract: A detector device for a gas chromatograph, for detecting surface ionization wherein ions will be detected which are formed upon contacting amine compounds and ammonia with the surface of metallic oxides having a large work function. The detector enables detection of poisonous amine compounds and ammonia with high sensitivity.

Abstract: The surface ionization detector for analyzing gas mixtures comprises a case (1) accommodating a thermoemitter placed at right angles to the direction of movement of a gas mixture and formed with electrically insulated extended ionizing elements, for example, parallel metal wires (9), each of which is connected to its current lead (11) to provide for independent regulation of heating power for each wire (9). The analyzed constituents of the gas mixture, the molecules of which are ionized through surface ionization, are ionized on the surfaces of the metal wires (9), desorbed therefrom and acted upon a potential difference of about several volts between the thermoemitter the ion collector (8) to move towards the ion collector (8) placed after the thermoemitter and made as a perforated element, for example, a metal mesh (13).

Abstract: An apparatus for monitoring the concentration levels of halogen gas in a gaseous atmosphere as confined in an enclosure over a relatively extended period of time. Such monitoring apparatus includes a sensor including first and second electrodes disposed to define a space therebetween through which the gaseous atmosphere flows and a voltage source for applying a voltage between the first and second electrodes whereby an ionization current flows to the first electrode. A control mechanism illustratively in the form of a programmed microcontroller monitors the ionization current collected by the first electrode as the output signal of the sensor, to determine an increase therein as would be indicative of a halogen leak. Upon determining an increase of the sensor output signal above a predetermined difference, the control mechanism removes the energization from the halogen sensor whereby the ionization current is terminated and the life of the sensor extended.

Abstract: Temperature programmed spectroscopy wherein particles of a substrate under investigation are attached in a non-overlapping manner to a heating filament. The temperature of the filament is increased in a controlled manner, thus increasing the temperature of the attached substrate particles as well. An instrument for analyzing the gases is a mass spectrometer. Gases desorbed from the particles can be studied according to this technique, or the nature of heterogeneous catalytic chemical reactions of a gaseous atmosphere on the particles' surface may alternativelRIGHTS OF THE U.S. GOVERNMENTThe invention described herein may be manufactured and used by or for the Government of the United States without the payment of any royalties thereon or therefor.

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: A gas sensor includes a pair of lead strips, a sensing element preferably comprised of a metal oxide semiconductor, such as SnO.sub.2, and extending between the pair of lead strips in the form of a bridge, a heater driver for supplying a heating current to at least one of the pair of lead strips, a detector for detecting a predetermined property of the sensing element, and a control circuit for controlling the operation of the heater driver and the detector. In one form of the invention, the detector is activated in a time period in which the heater driver is not activated. In another form of the invention, the pair of lead strips are connected in parallel or in series when the heater driver is to be activated. In a further form of the invention, the heater driver is normally operated periodically, but when the detector first detects a predetermined condition, the heater driver is operated continuously.

Abstract: An apparatus for measuring a gas concentration in a hot gas sample withdrawn from a process chamber, comprising a metal block (10) adapted to be tempered and housing at least the detector (12) and those components of the flow path guiding the gas to be measured between a sampling probe and the detector. A suction pump (14) sucks the gas sample into the metal block (10) where the gas to be measured is divided into two conduits. The first conduit leads to the detector and the second conduit back to the process chamber.

Abstract: A method and apparatus are employed to detect the onset of soot or smoke formation in a flame exhaust. A pair of oppositely charged electrodes are placed in a flame located where soot formation is likely to occur. Varying voltages are applied across the electrodes and the limiting current, as the voltage is increased, called the saturation current, is measured. Generally, the saturation current decreases for higher fuel-to-air ratios in non-sooting flames. When the threshold for soot formation is approached, a definite saturation current is no longer observed and the current through the electrodes increases rapidly with increasing applied electrode voltage. The detection of the rapidly increasing current during sooting conditions is indicative of the formation of the soot itself.

Abstract: Method and apparatus for analyzing specific chemical substances in a gaseous environment comprises a thermionic source formed of multiple layers of ceramic material composition, an electrical current instrumentality for heating the thermionic source to operating temperatures in the range of 100.degree. C. to 1000.degree. C., an instrumentality for exposing the surface of the thermionic source to contact with the specific chemical substances for the purpose of forming gas phase ionization of the substances by a process of electrical charge emission from the surface, a collector electrode disposed adjacent to the thermionic source, an instrumentality for biasing the thermionic source at an electrical potential which causes the gas phase ions to move toward the collector, and an instrumentality for measuring the ion current arriving at the collector.

Abstract: A cation emission type halogenated hydrocarbon gas detecting element comprising a cation source, a heating means and an ion collector electrode, which is characterized in that said cation source consist essentially of .beta.-Al.sub.2 O.sub.3, wherein substantially all cation species occupy a position in the crystal lattice structure of the source. By employing .beta.-Al.sub.2 O.sub.3, the detecting element can be more miniaturized and can work at lower temperature than a conventional cation emission type electrode comprising the cation source made of steatite.

Abstract: The flame ionization detector includes basically a nozzle for a measuring gas fuel gas mixture and is coaxially disposed to a target electrode. Materials and dimensions for these components are critical and include a platinum metal nozzle tip, a noble metal surface target electrode, a limited range for the nozzle duct diameter, a limited range for the relative position between the nozzle tip and the lower end of the target electrode, and angle ranges for conical nozzle contour surfaces.

Abstract: Alkali metal detectors previously employed in coal gasification systems are not suitable for use in combustion gas streams because of the high temperatures involved. In the present invention, alkali metal detector elements are mounted on a heat resistant flange including at least one shielded electrical ceramic feed-through. This flange is cooled to ensure the nonconductivity of the ceramic insulation.

Abstract: An ionization detector which ionizes particles of a substance to be easily ionized and then measures the number of the ionized particles as ionization current. The detector comprises a heater for ionizing particles, a collector disposed opposite to the heater for collecting ionized particles, and a control arrangement for controlling the temperature of the heater to a constant value. Thus, by preventing the fluctuation of the temperature of the heater due to the fluctuations of the voltage of the power source and of the flow of a cooling fluid which is detected as the ionized particles, an exact measurement of the number or concentration of ionized particles can be performed.

Abstract: Disclosed is a sodium ionization detector (SID) for detecting sodium leaks by detecting the magnitude of fluctuation of the ion current produced by thermally ionizing sodium. There is a particular relationship between the magnitude of fluctuation of the ion current and the concentration of sodium. The sodium ionization detector is adapted to determine the magnitude of fluctuation of the ion current so as to compare it with a predetermined value. The magnitude of fluctuation of the ion current is determined, for example, by the root-mean-square value of a fluctuation component of the ion current.

Abstract: An arrangement for monitoring the concentration of potentially explosive substances in gas streams includes a first flame-ionizer and a second flame-ionizer, both ionizers being accommodated in a common chamber which is maintained at a predetermined temperature, such as 180.degree. C. A common conduit for supplying both ionizers with a fuel gas is provided in the arrangement. A common conduit for feeding both ionizers with combustion air is mounted in the arrangement. Each ionizer is provided with an individual conduit connecting the assigned ionizer with a respective drying chamber of a coating installation. A sample gas stream discharged from the respective drying chamber is fed into the assigned ionizer through a capillary pipe and passed through a flame produced in each ionizer. The electric current flowing between the electrodes in each ionizer shows the concentration of potentially explosive substance in gas streams being tested.

Abstract: A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

Abstract: A device for detecting alkali metals in gas streams includes a conduit defining a gas-flow cavity and a metalliferous filament having a work function of at least 5.6 ev extending transversely through the flow path. A heater heats the filament to ionize the alkali metals being detected. A perforated ion-collection member surrounds the filament to define an ionization-collection region. A high-voltage (HV) source develops a HV electrical field within the region, thereby effecting neutralization of the ionized metals contacted with the collection member. An ammeter generates a signal in response to the neutralization and proportional to the rate thereof. A detection method which can be performed by the device is also described.

Abstract: An electrode structure for a halogen leak detector is disclosed in which the cathode portion is provided with a hollow metal tube through which air or other cooling fluid is passed. This hollow metal tube may also serve as the cathode electrical connection and for mechanical support. Since halogen leak detector systems are typically provided with air pumps for the passage of ambient air through the detector, it is a simple matter to also pass a stream of ambient air through the hollow metal tube in the cathode in order to maintain the cathode at a lower and more controlled temperature, thereby increasing the sensitivity of the detector and prolonging its useful life.

Abstract: An instrument for the analysis of a sample material to detect the presence of specific substances that thermally decompose into electronegative species comprises a sensitized surface, means for heating the sensitized surface in a gaseous environment to generate a gaseous boundary layer adjacent the sensitized surface, means for causing the sample material to interact with the sensitized surface to form negative ions, a collector electrode maintainable at a different electrical potential from the sensitized surface to cause a current of these negative ions to the collector electrode, and means for measuring the ion current. The sensitized surface is formed on a ceramic body that is impregnated with an alkali metal. The composition and temperature of the sensitized surface, and the composition of the gaseous boundary layer are selected according to the specific substance to be detected.

Abstract: Smoke is detected by a surface ionization effect on a heated wire filament disposed opposite a negative ion collector electrode. Current flow between the wire and the electrode increases in the presence of smoke. The increase is probably attributable to surface ionization of smoke particles on the heated wire.