Method of detecting admixture in gas

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises setting the cell composed of metallic cathode and anode into the gas to be analyzed and irradiating the cell in ultraviolet spectrum. The radiation flux knocks photoelectrons out of the surface, which is a reason of gas conductivity. The voltage applied to the electrodes induces current in the interelectrode space. When the gas composition changes, the interelectrode current also changes.

EFFECT: decreased power consumption.

2 dwg

 

The invention relates to indicators of impurities in the gas environment, and above all, leak detectors, recording the appearance of electronegative gas in the atmosphere of nitrogen or air.

Modern production is increasingly used devices that require the use of vacuum technology. This dictates the development of modern methods of monitoring the integrity of the process equipment.

There is a method of detecting the test gas resulting from the unpressurized locations of the test volume based on the change settings excited by a high frequency electric field of the plasma from a test gas. (Plasma leak detector TP-4. Technical description and operating instructions. EUNI).

When pumping vacuum pump air through adjustable leak in the ionization chamber located between the plates of a capacitor included in the circuit of the generator, at a pressure of from 100 to 200 PA under the influence of high-frequency electric field of the plasma occurs, the damping circuit and breaking a generation. The subsequent recombination of the charge carriers leads to the restoration of generation and the re-emergence of plasma.

During the flow through the chamber ionize the air, not containing a test gas, the process is repeated with a frequency of not more than 10 kHz. The appearance of the trail banner is gas in the air increases the rate of recombination of the charge carriers and increases the repetition rate of slaking process - sunbathing discharge (up to 200 kHz).

The disadvantage of this method is the need to have a Sipper device (booster pump).

Another disadvantage of this method is the need to set fire to the discharge in an atmosphere of air, since it requires additional energy consumption.

Listed two factors increase the weight of the device and increases its power consumption (power consumption 40 VA and weight more than 5 kg).

Closest to the claimed method is used in electrodesiccation the leak (the Leak detector of GATE-9-001. Technical description and instruction leak detector).

In this method measured the electrical conductivity of the discharge gap during the air intake into the interelectrode gap. The presence of the air electronegative gas, indicating the presence of leaks, reduces the conductivity of the plasma.

The disadvantage of this method is the need to set fire to the discharge at atmospheric pressure, which is associated with the use of environmentally hazardous (radioactive) of the pre-ionizer and require a high energy consumption (power consumption 20 VA, weight 4.4 kg).

The purpose of this invention is the detection of impurities in the gas medium used, in particular, to determine leakage from the closed volumes, environmentally friendly SPO is obom with lower power consumption compared to existing methods.

The task is solved in that a method for detecting impurities in the gas phase is based on measuring changes in the magnitude of the electric current passing through the analyzed environment when changing its composition, when placed in a medium in the space between the cathode and anode of the cell. The space between the anode and cathode is irradiated with ultraviolet radiation and between the cathode and the anode applied voltage. To change the sensitivity of the method of changing the distance between the cathode and the source of ultraviolet radiation in order due to the absorption of radiation by impurity to change the flux density of radiation.

The advantages of this method consists first of all in that it avoids the use of environmentally harmful radioactive pre-ionizer environment, which is used in the aforementioned method.

Another important advantage is low power consumption using the proposed method due to the fact that in this method there is no need to set fire to the discharge in the analyzed environment at atmospheric pressure, as is done in the prototype. The discharge used in the irradiating lamps in the proposed method consumes electrical energy several times less, which explains its efficiency.

Example. The method of detecting impurities in a gaseous environment op who was obivoulsy in a special sealed chamber, zapolneniya controlled gas mixture. The camera was placed cell, consisting of a metal plate cathode and a metal mesh anode. In this chamber was the source of ultraviolet radiation for irradiation of the cathode. (figure 1). The power consumed by the source from the electrical network, was 5 watts. An airtight chamber with the cell and the source of UV radiation was pumped to a high vacuum and then filled with a mixture of nitrogen with oxygen given percentage composition. The range of variation of the impurity oxygen in nitrogen was from 1 to 10000 PA. Between the anode and cathode were applied voltage (100 V), which created the current in the electrode gap. The amount of current at a constant voltage between the electrodes depended on the concentration of electronegative gas (oxygen) in the mixture (at a pressure of a mixture of 1 ATM).

The results of the experiments are presented in figure 2. From the obtained dependence is easy to estimate the maximum sensitivity of detection of oxygen, it is equal to 100/10-5ATM. the oxygen. This means that when you register the changes of the currents at level 1 on this method it is possible to “feel” 10-5% oxygen in nitrogen. Modern measurement methods provide detection of small currents up to 10-15A. This means that the potential of the proposed method which may serve as an indicator of oxygen at the level of 10 -10-10-10%that goes far beyond existing implementable opportunities for the creation of environments with controlled parameters of impurities in them.

To change the sensitivity of the method, the distance between the cathode and the source of UV radiation was changed to due to the absorption of radiation by impurity to change the flux density of radiation. Thereby change the flow of electrons, pulling out from the surface of the cathode, which resulted in a change in the current cell while maintaining the impurity concentration.

Thus, the result was achieved without the use of environmentally harmful drug with a power consumption of 5 watts.

The method of detecting impurities in a gaseous environment, based on the measurement of the electrical current flowing in the cell that is in a gaseous environment, and includes a cathode and an anode, between which the applied voltage, wherein the cell is irradiated with ultraviolet radiation that can cause the photoelectric effect, ensuring the electrical conductivity of the gas environment in the cell, the distance between the cathode and the source of ultraviolet radiation may change, leading to changes in ultraviolet radiation flux at the cathode surface and, accordingly, to change the sensitivity table is impurity.



 

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FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises setting the cell composed of metallic cathode and anode into the gas to be analyzed and irradiating the cell in ultraviolet spectrum. The radiation flux knocks photoelectrons out of the surface, which is a reason of gas conductivity. The voltage applied to the electrodes induces current in the interelectrode space. When the gas composition changes, the interelectrode current also changes.

EFFECT: decreased power consumption.

2 dwg

FIELD: instrument industry.

SUBSTANCE: detector comprises housing which is the cathode of the detector, devices for supplying and discharging gas to be analyzed, anode, tritium target, and insulator housed in the space between the electrodes. The working surfaces of the electrodes are parallel and mounted with a spaced relation to each other with the use of the insulator. The detector is provided with current lead and current collectors. The insulator is made of a ring made of silicate-containing material and is interposed between the electrodes.

EFFECT: enhanced stability of operation and prolonged service life.

2 cl, 1 dwg

FIELD: measurement engineering.

SUBSTANCE: method is based upon introduction of preliminary prepared gas sample, ionization of components of sample and mass-spectral registration of ions. Ionization is completed by means of combination of glow discharge and electron impact when using ionizer which has to be assemblage made of high-melting capillary and thin-walled metal hollow cathode. Sample together with flow of microcavity discharge gas-suppressor is introduced into hollow cathode through capillary. Device is provided with electron gun mounted directly behind skimmer on the axis of supersonic gas jet. Hollow cathode is connected with capillary intended for introducing sample. Port of gas-discharge camera intends for introduction of ballast gas. There is ionizer inside the gas-discharge camera.

EFFECT: widened analytical abilities of gas mass-spectrometry.

7 cl, 3 dwg

FIELD: analytical instrumentation engineering; photoionization gas analyzers built around ultraviolet lamps.

SUBSTANCE: proposed ultraviolet lamp has sealed body filled with gas mixture emitting in vacuum ultraviolet region and device for striking discharge within lamp. Lamp body accommodates heating element designed for heating light outlet window. Photoionization gas analyzer has ionization chamber with pipe union for feeding gas (air) being analyzed, ionization source in the form of ultraviolet lamp, electrodes installed within ionization chamber, and microprocessor used for processing signal being measured and for monitoring gas analyzer in operation. Heating element used for heating lamp window is made in the form of resistor disposed near lamp window or directly on inner surface of window; it also has temperature sensors of which one is disposed on lamp window surface, and temperature sensors are installed outside ionization chamber case.

EFFECT: reduced power requirement and size of lamp.

4 cl, 4 dwg

FIELD: multi-parameter control.

SUBSTANCE: method includes forming low-temperature plasma for ionization of gas environment in said volume, two-electrode converter is excited in turns by currents of not less than two different fixed resonance frequencies for forming of different strengths of electromagnetic field near electrodes in accordance to number of fixed frequencies. During scanning of plasma area by converter electric conductivities between electrodes of converter on fixed frequencies and on basis of conduciveness gas composition and also other micro-admixtures are detected and evaluated in volume of environment.

EFFECT: broader functional capabilities, higher efficiency.

3 dwg

FIELD: measuring technologies.

SUBSTANCE: method includes ionizing controlled gas by β or α particles with periodical collection of ionization charges from gas volume. Using charge-sensitive amplifier, only charge of gathered electrons is registered from each α and β particle, or in even time intervals, of adjustable length. To abolish ambiguousness of measurements in noble gases, ultra-pure molecular gas is added to them, effectively thermalizing electrons, drifting in gas under effect from electric collecting field.

EFFECT: broader functional capabilities, higher precision.

2 cl, 3 dwg

FIELD: test equipment.

SUBSTANCE: method can be used for making method of inspection of thermo-emission condition of surface-ionization ion thermo-emitter easier. It allows conducting inspection of effectiveness, uniformity and selectivity of ionization of organic compounds on the surface of thermo-emitter during common measurement cycle without usage of test samples of organic compounds. Atmospheric pressure air is pumped close to surface of thermo-emitter at volumetric speed of (2-10) l/min. Humidity of air is put under control. Constant voltage of (30-600) V is applied between thermo-emitter and ion collector. Thermo-emitter is subject to heating at constant speed of heating. Thermo-emitter ion current temperature dependence is registered. Values are determined which characterize peaks of ion current at preset temperature dependence (position of peaks, current intensity, width of peaks, and speed of raise of peak currents). Thermo-emission condition of thermo-emitter is judged from values of received characteristics.

EFFECT: simplified procedure of inspection; elimination of test samples.

7 cl, 5 dwg

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises setting one of the crystallographic planes of monocrystal of oxide bronze in coincidence with the flat working surface of the thermal emitter, pumping air between the surface of the thermal emitter and auxiliary electrode, recording background ion current of the thermal emitter, and determining the intervals of operation temperatures of the thermal emitter from the temperature dependence of the background current.

EFFECT: enhanced efficiency.

4 cl, 2 dwg, 1 tbl

FIELD: spectrometry; measurement technology.

SUBSTANCE: pure argon or impurity-free mixture of argon and gas, which has to carrier in sample to be tested, is used as counterflow gas in separation area of ion mobility spectrometer. Mixture has at least 80 percent by volume of argon in case argon/nitrogen mixture is used and at least 50 percent by volume of argon in case argon/hydrogen or argon/oxygen are used. Relation of discharge of argon or argon mixture and discharge of hydrogen equals to 10 and bigger, predominantly, from 15 to 25. Relation of argon discharge or argon mixture to discharge of nitrogen equals to 5 and higher, predominantly from 5 to 10. Relation of argon discharge or argon mixture to discharge of oxygen belongs to interval of either 0,3-1,5 or 6-10, predominantly around 0,5 or 8.

EFFECT: improved efficiency of peak selection at spectrometric curves.

4 cl, 8 dwg

FIELD: analysis of gaseous and liquid media.

SUBSTANCE: method can be used for solving problems of matrix-free method of de-sorption/ionization of chemical compounds by using ion emitters with active layer produced for reproducibility, which layer provides high-sensitive quantitative analysis of gaseous and liquid media in real time. Method of de-sorption-ionization of chemical compounds, intended for usage during subsequent mass-spectrometric determination, is based upon formation of active layer onto surface of substrate, onto application of molecules of chemical compounds onto it by means of adsorption or deposition, and onto subsequent ionization and de-sorption of ions from surface of substrate due to influence onto substrate by electromagnet radiation or by flux of particles. Formation of active layer of substrate includes creation of split chemical bonds in volume of substrate and/or onto its surface with concentration no lower than 1014 cm-3 by means of introduction of structural disordering of substrate's surface, or deposition of nano-sized particles onto surface of substrate either creation of amorphous layer of material onto surface of substrate.

EFFECT: improved precision of analysis of gaseous and liquid media.

19 cl, 8 dwg

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