Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/0004—Gaseous mixtures, e.g. polluted air
  • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
  • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
  • G01N33/0031—General constructional details of gas analysers, e.g. portable test equipment concerning the detector comprising two or more sensors, e.g. a sensor array
  • G01N33/0032—General constructional details of gas analysers, e.g. portable test equipment concerning the detector comprising two or more sensors, e.g. a sensor array using two or more different physical functioning modes

Definitions

• the invention relates to a method and equipment for defini- tion of foreign matter contents in gas.
• the most sensitive analysis devices are based on air ioniza- tion, e.g. by alpha- or beta radiation and by measuring the ions in different circumstances.
• he ions so formed are put to migrate through a particular abyrinth and the remaining ions are measured based on the ci-irent they cause.
• Another method analyzes the mobility of the formed ions through certain lattices and finally measures the ion current. These two methods generally detect very heavy molecules from the air, like most of the combat gases.
• the ionized molecules are led through chambers having different electric fields, after which the current is detected from the measuring electrodes, by which the quality and quantity of the foreign matter molecules are identified.
• the DE-patent publication 2028805 discloses a method for detecting trace vapors, which undergo ion-molecule reactions and for separating, concentrating and measuring of molecular quantities of trace substances in gaseous samples.
• the detection and measurement is accomplished by utilizing the difference in velocity or drift time of ions of different mass in the electric field applied to the gas stream.
• the electric field causes the primary ions to migrate towards a plurality of ion gates provided rectangular to the gas stream and in parallel between the electrodes, during which the primary ions react with molecules of a gas to be detect- ed, converting the molecules to secondary or product ions, thereby measuring and classifying the ions according to the particular mass.
• the CH-publication 550 399 discloses an air pollution mea- suring equipment comprising a first and a second air capaci ⁇ tor each having a suitable length through which ionized air containing pollution flows laminarily at a constant veloci ⁇ ty.
• the capacitors may have planar or cylindrical electrodes and may comprise two or more electrodes.
• the electrodes of the capacitors are supplied with different voltages.
• the output signals measured via the electrodes of the capacitors are applied to the inputs of dividing and summing circuit means, the output of which provide a final output signal which constitutes a measure of air pollution.
• One of the most important advantages of the invention is that the inaccuracy of the analysis due to gas or air mois ⁇ ture can be eliminated.
• the reliability of the analysis is improved.
• the sensitivity is great and the response time is short.
• Other organic substances or solvents or tobacco smoke do not disturb the foreign matter analysis.
• Fig. 1 presents a diagram of the measuring equipment of the subject invention.
• Fig. 2 presents a diagram of another implementation form of the equipment.
• Fig. 1 presents the equipment according to the invention.
• the gas to be analyzed is sucked into tube 1, filtered with the heatable filter 2 and led into the ionization cell 3, of which can as such be provided several in parallel or in sequence, and which can either be according to the FI patent 75055 or any gas ionization based gas analysis device, whereafter the gas is led to the semiconductor cell, which can be several in parallel or in sequence.
• the semiconductor cell can in the solution be any gas sensor based on the reaction between the semiconductor surface and the gas, which as such is based on the known technique.
• the signals of all measuring cells are utilized simultaneously for the perfor ⁇ mance of the gas analysis for calculations and other conclu ⁇ sions for improved separation of gases from each other in different circumstances.
• the gas is e.g. charged by the radiation transmitted from the alpha- or beta radiation source 4.
• the gas is led to a measuring tube 5.
• the field elec- trodes have the voltage V l V 2 ....V n .
• the back-plate voltage is V ⁇ .
• the light ions charged in the gas are collected into the field electrodes V n .
• the further advanced remaining heavy ions cause an ion current I n to the electrodes in the chamber border, which is registered. From each value I n , in which n is an integer, e.g. 1-6, is formed a diagram, the form of which depicts the substance to be analyzed. Normally the electric field of the ionization cell is stronger in the beginning of the chamber and weaker in the collecting zone.
• the gas is led further to the semiconductor cell 6, formed of e.g. a tin dioxide(Sn0 2 )crystal.
• a sensitive analyzing device can be obtained for different substances, e.g. for mustard gas.
• the signals obtained by the above method and the semiconductor cells are gathered together and analyzed together in e.g. a data processor 7.
• the gas analyzed by the semiconductor cell together is preferably such a gas, which analyzed as moist, does not give a signal with the above mentioned ionization method but only when measured by the semiconductor cell.
• An example of such a gas is the mustard gas.
• the tests for the gas streams having hazardous matter in it have been carried out in different humidities with both the ionization cell and the semiconductor cell mounted sequen ⁇ tially or parallel to each other.
• the relative humidities were 10, 50 and 90 %.
• the gas stream was conducted through the channel by a pump.
• test results show that the presence of the mustard gas will be detected most effectively using the combination of the ionization and semiconductor cell at low concentrations and at all the relative humidities and especially at the moderate or larger humidities.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Analytical Chemistry (AREA)
• Food Science & Technology (AREA)
• Medicinal Chemistry (AREA)
• Physics & Mathematics (AREA)
• Combustion & Propulsion (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Sampling And Sample Adjustment (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1993
  • 1993-01-12 FI FI930122A patent/FI96903C/fi not_active IP Right Cessation
• 1994
  • 1994-01-12 EP EP94904196A patent/EP0679255A1/en not_active Withdrawn
  • 1994-01-12 CA CA 2153657 patent/CA2153657A1/en not_active Abandoned
  • 1994-01-12 WO PCT/FI1994/000015 patent/WO1994016320A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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