Method for determining component concentration in two-component gas mixture
FIELD: fire safety.
SUBSTANCE: method for determining component concentration in a two-component gas mixture placed in a measuring chamber based on the use of the thermal conductivity of a controlled gas mixture, at first the mass m of the controlled component id calculated in the gas mixture according to the formula m=ρ vc (λcm1+λcm2-λcm12)/λcm2, where ρis the density of the controlled component, vc is the volume of the chamber, λcm1 is the thermal conductivity of the first component, λcm2 is the thermal conductivity of the second controlled component, λcm12 is the thermal conductivity of the gas mixture. Then, taking into account the mass of one molecule of the second controlled component, the concentration of the required parameter is determined.
EFFECT: increased accuracy of measuring the concentration of a component in a two-component gas mixture.
FIELD: gas chromatographic devices; chemical industry; oil industry; metallurgy; medicine; biology etc.
SUBSTANCE: detector can be used in gas chromatographic device as with filled and empty capillaries and micro-nozzle separating columns for analyzing complex mixtures of matters having as natural and artificial origin. Detector has heater made in form of metal thread, two film thermo-sensitive elements mounted in gas channel at output of chromatographic column in parallel to the heater at similar distance. Thermo-sensitive elements are connected into opposite arms of bridge circuit. Electric current source for the heater has automatic controller to keep temperature and resistance of the source to permanent value.
EFFECT: improved precision of detection; improved sensitivity.
SUBSTANCE: in thermocatalytic detector operating in static mode, they limit diffusion of analysed gas mixture into a reaction chamber, sending it via a calibrated hole of small cross section, and diffusion balance is set between flows of arriving and oxidised flammable gas on a SE at incomplete (half and less) involvement of efficiency of the working SE, providing for efficiency reserve, which, as sensitivity gradually reduces, automatically takes action, maintaining stability of measurements and extended service life of the detector.
EFFECT: realisation of the method is most favourable with minimised volume of a reaction chamber and dimensions of sensitive elements.
3 cl, 3 dwg, 1 tbl
FIELD: measurement equipment.
SUBSTANCE: sensor to measure concentration of one of gas mixture components comprises a channel in a body with an attachment at the inlet and a sonic nozzle at the outlet, a thermoanemometric sensitive element in a channel, in the wall of which there is a hole for pressure measurement. The attachment is arranged as replaceable with permanent or temporary diameter of a channel along the length of the attachment, and in the channel of the sensor additionally there is a heat-sensitive element installed for measurement of mixture temperature inside the channel, at the same time the concentration of gas mixture is determined according to calibration dependencies produced under controlled conditions. The replaceable attachment may be arranged with a conical or streamlined cylindrical shape, and also in the form of an adapter for connection with a closed source of the investigated gas mixture.
EFFECT: possibility to measure concentration in flows of mixtures with a temperature gradient.
3 cl, 5 dwg
SUBSTANCE: thermocatalytic methane alarm differs from existing alarms in that one of the two digital-to-analogue converters (DAC) in the microprocessor module, specifically DAC-1, performs the function of setting the supply pulse with multistep form with given amplitude and duration of each of the steps, and DAC-2 generates the bias potential in synchronisation with signals from measurement steps of the supply pulse. The output of DAC-1 is connected through a preamplifier to the sensor input, and the output of DAC-2 is connected to the inverting input of the amplifier-measurement unit.
EFFECT: reduced power consumption while preserving metrological characteristics which comply with home methane alarm regulations.
2 cl, 3 dwg, 1 tbl
SUBSTANCE: according to the invention, the method and apparatus for detecting methane are based on using a cyclic mode of operation of a micropower thermochemical (catalytic) sensor, consisting of a working and a comparative sensitive element connected into a bridge measurement circuit and placed in a reaction chamber with diffusion access of the detected gas mixture through a microporous explosion-proof ceramic-metal gas-exchange filter. The disclosed method involves forcing heat-mass-exchange of the sensitive elements in a transient process, which is achieved due to that a current (voltage) pulse in each cycle is generated by stepped variation of the pulse amplitude, initially transmitting a pulse whose amplitude is 1.5-2 times higher than the nominal operating value and duration which is sufficient to achieve the working temperature of heaters, the amplitude is then instantly lowered to the operating value and the response (output signal) is measured in the initial phase of thermal equilibrium (≥95% of the steady-state value of the output signal) at a strictly fixed time. The disclosed device includes membrane-type sensitive elements made using micromachining technology from nanoporous anodic aluminium oxide (AAO) with thin-film platinum heaters, current leads and contact pads sputtered on the surface of the membrane, wherein the main part of the membrane, according to its purpose and its functions, on which there is a heater-resistance thermometre and a catalytically active coating on the working element and a passivating coating on the comparative element, is in form of a cantilever separated from the basic mass of the membrane and the connected two cross members made from AAO with sputtered platinum thin-film current leads, wherein the geometric configuration of the cantilever and its defining dimension d' are minimised to values at which a film-type mode of heat transfer is realised, characterised by coefficient of heat transfer α=0.5λ/d', where λ is the heat conductivity coefficient of the air medium surrounding the cantilever.
EFFECT: possibility of designing a sensitive element with a substrate made from anodic aluminium oxide, with minimisation of heat removal by convection and heat conductivity of the material of the platform, as well as shorter time for the transient process of heating the sensitive element to increase its efficiency when operating in pulsed mode.
2 cl, 2 ex, 15 dwg, 2 tbl
SUBSTANCE: method of determining the phase of a gas-liquid stream involves determination of the distribution of characteristics of the gas-liquid stream in the cross-section of a pipeline by installing into the pipeline a sensor with a detecting element(s) connected to a measuring device, measuring the change in sensor parameters and transmitting a data signal on the change in sensor parameters. Analysis of flow parameters is carried out using a phase sensor with a thermistor detecting element(s), having a "point" design. The state of the detecting elements is polled. Change in resistance of the thermistors, which is associated with phase change of the medium in horizontal layers of the gas-liquid stream is determined at control points on the vertical axis of the cross-section of the pipeline. The signal is processed and information on the state of the stream is transmitted. If there are several detecting elements, they are connected to the measuring device independently of each other on parallel circuits and their state is polled periodically. The invention also discloses an apparatus for realising the method.
EFFECT: high accuracy of determining the phase of a gas-liquid stream, high reliability and simple design of the apparatus.
3 cl, 4 dwg
FIELD: physics; electricity.
SUBSTANCE: two consecutive voltage measurings are carried out at connection of measuring body with different input resistances, control resistor and divider between general minus busbar of radiants and case. The equivalent resistance and voltage between the minus busbar and the case are calculated on the measured two values of voltage calculate taking into account divider and the control resistor, then the equivalent resistance of voltage between the minus busbar and the case is calculated taking into account the control resistor after that calculate insulation resistances of busbars. The calculated insulation resistances of radiants are compared with Rk the busbar with the underestimated insulation resistance is determined by the results of comparison. Delivery of commands, inquiry of the measured voltages, evaluation and formation of effects of the control are carried out by means of the program module.
EFFECT: determination of real values of insulation resistance of busbars of independent radiants having one general busbar.
FIELD: hygrometers with bolometric heat sensitive member, stove or furnace using such hygrometer and method for controlling stove or furnace.
SUBSTANCE: hygrometer includes two static bolometric heat sensitive members for accurate detection of humidity value. Stove or furnace includes bolometric hygrometer secured to one side of bracket in air discharge opening for deflecting direction of air flow in order to detect humidity value at high accuracy in cooking chamber. Method for controlling operation mode of stove or furnace provides different periods of heat treatment of food products in package or without it.
EFFECT: enhanced accuracy of humidity measuring.
13 cl, 15 dwg
SUBSTANCE: system consisting of a test specimen fixed between two similar standard specimens made from the same transparent material of known thermal conductivity, where all specimens are made in the form of right cylinders with similar bases and are brought into contact with their end faces, is placed into an interferometer. At creation in the system of a stationary one-dimensional heat flow directed perpendicular to the plane of contacts, change of the shape of the light beam phase of the interferometer, which passes through the standard specimens, is measured, and thermal conductivity is calculated based on the measured change of the profile of the light beam phase of the interferometer, thermal conductivity of the standard specimens and height of the test specimen.
EFFECT: improving accurate determination of thermal conductivity of specimens of a small size.
FIELD: measurement equipment.
SUBSTANCE: method consists in heating of one of surfaces of a sample or its section to the maximum temperature which is maintained to the moment when the measured difference of temperatures on boundaries of the studied section decreases to a preset value. Then the heating power is decreased until the stage of sample cooling with the measured rate of change of temperature which does not exceed the pre-set value. The specific amount of heat, temperature increment on boundaries for two consecutive intervals of time are measured, first of interval is defined by the moments: heat supply and achievement of pre-set rate of change of temperature. Heat conductivity and a volume heat capacity are determined by formulas.
EFFECT: increase in accuracy of determination of thermophysical properties and reduction of time of measurement.
SUBSTANCE: essence of the method consists in heating the solid body of cylindrical shape by contact method using the pipeline with the coolant moving inside it. According to the known mass flow and temperature of the coolant its speed and flow regime is determined. According to the known speed, the coolant flow regime and the preset temperature of the inner surface of the pipeline the heat emission coefficient between the coolant and the inner surface of the pipeline is determined. According to the known temperature of the outer surface of the solid body, measured by contact or non-contact temperature meter, and the environment the heat emission coefficient between the outer surface of the solid body and the environment is determined. According to the equation of heat emission for a two-layer cylindrical wall under steady temperature condition the thermal conductivity coefficient of the solid body is determined.
EFFECT: increase in accuracy of determining the thermal conductivity coefficient of a solid body of cylindrical shape under steady temperature condition.
SUBSTANCE: method is implemented by two thermal effects on two-layer plate with the subsequent cooling, measurement of temperature difference and heat flux. The sample is set with the surface of coating on the heat receiver and the heater. The temperature difference is measured at the points on the opposite surface of the plate, one of which is located on the boundary closest to the heater. Additionally the temperature difference is measured between this point and the environment. The integration starting time is set at the first cooling, and the termination is determined during the second cooling, upon reaching the same temperature difference that at the start. The thermal conductivity is determined by the formula.
EFFECT: increase in accuracy and simplification of determining the thermal conductivity.
SUBSTANCE: method is implemented by heat action on a specimen with further cooldown, measurement of temperature difference at boundaries of the test section of the specimen and amount of heat supplied to it during a difference integration period. In addition, the second heat action is performed; temperature drops are measured at these boundaries relative to environmental temperature; time of the beginning of integration is set at the stage of the first cooldown, and its end is determined at the second cooldown, at the moment of equality of weighted sums of temperature drops at the specified points of time: Δt(0, τ2)+pΔt(L, τ2)=Δt(0, τ1)+pΔt(L, τ1), where τ1, τ2 - time of the beginning and end of integration, p - weight coefficient. Heat conductivity is determined by the formula.
EFFECT: increasing accuracy of determination of heat conductivity.
FIELD: oil and gas industry.
SUBSTANCE: stopped well is chosen; its flushing is performed, and with that, temperature at the circulation system outlet is recorded. With that, pumping of hot liquid (heat carrier) is performed through annular space, with that, at its inlet the liquid temperature varies as per a periodic law and is recorded, and heat conductivity coefficient λ"п" and coefficients of heat transfer through tubing strings k1 and casing string k2 are calculated as per mathematical formulas.
EFFECT: improving measurement accuracy of an average integral value of heat conductivity of mine rocks as to a well log and determining coefficients of heat transfer through the tubing strings and through the casing string, length of the circulation system of the well.
SUBSTANCE: device for contactless determination of heat diffusivity of solid bodies contains a flat optical heater and a thermal imager connected to a computer, optically opaque mask for formation of spatial heating field. The device also contains the optical lens intended for focusing of thermal radiation of the flat optical heater and optically opaque shutter allowing to open and close the thermal radiation of the flat optical heater in certain moments.
EFFECT: improvement of accuracy of contactless determination of heat diffusivity of solid bodies.
FIELD: measurement equipment.
SUBSTANCE: invention relates to thermal physics and may be used to determine extent of blackness of the surface of composite and thin-film materials. The method is based on application of sample surface heating and registration of radiation temperature from the sample with coating and available value of blackness extent and from the sample without coating. The proposed solution provides for localisation of the measured section area by means of a special screen from noise impact, and also creation of a local heating area, stable by temperature and area from a special source of heat of directed action. Also application of an IR-mark is provided for preliminary identification of thermal field parameters and operation with least losses.
EFFECT: increased validity of material surface blackness extent determination.
11 cl, 4 dwg