Method to measure relative air humidity
FIELD: measurement equipment.
SUBSTANCE: in the method to measure relative air humidity based on measurement of difference of oscillation frequencies of resonators - a working and a reference ones with subsequent amplification of an analytic signal and regeneration of film coatings with an inert gas, three piezoquartz resonators are used with internal oscillation frequencies of 13-16 MHz, two of which are working ones with different hydrophilic coatings, properties of which are optimised for operation in a certain range of temperatures, and one is a reference resonator without a film coating, which supports the permanent frequency of oscillations, at the same time the device is equipped with a switch of working resonators.
EFFECT: measurement of relative air humidity in a wide range of temperatures, also in the negative range, higher accuracy of measurements, reduced time of regeneration of film coatings of resonator electrodes.
The invention relates to measuring technique and can be used to measure relative humidity from 0 to 100% in the temperature range (- 20÷50)°C.
Known methods of measuring the relative humidity (see Moscow VA, stack I.A., Fisenko A.N. Methods and means of hydro-meteorological measurements. - Voronezh: VAIO, 2009. - P.77 - 100) are characterized by high precision measurements of relative humidity above 40%. The measurement accuracy is significantly reduced at low temperatures, less than (-3)°C (phase transition).
The relative humidity in a wide range of temperatures measured with the aid of piezoresonance sensors, which are a kind of selective converters sorption type and is made on the basis of piezoquartz resonators (CRP) with the selective moisture-sensitive coatings. The amount of adsorbed moisture depends at a given temperature, the ratio of partial pressure of water vapor ppthe vapour pressure pnat this temperature. Thus, CRP converts the ratio Rp/pn(or relative humidity) in frequency, and analytical signal method does not depend on the aggregate state of water.
There is a method of measuring the relative humidity based on the application of p is tortonese sensor, contains one piezoquartz resonator at-cut with a semiconductor substrate and a hydrophilic film coating (see EN 2141639, IPC G01N 5/02). Relative humidity is determined by the absolute change of the frequency of oscillations of CRP in the sorption of water vapor on the film surface. The sensor is characterized by high sensitivity, operates in a wide temperature range. The disadvantage of a narrow interval of the measured relative humidity due to the low sorption capacity of the film coating of the electrodes CRP, which leads to the disruption of the oscillation frequency when the relative humidity is 0.22%.
Closest to the claimed technical solution is a way of measuring the relative humidity of the air, based on the measurement of the difference frequencies of the two resonators with frequencies of oscillation 9 MHz - working and reference (see VV Malov. Piezoelectric sensors. - M.: Energoatomizdat, 1989. - S - 189). The electrodes of the resonators modified various film coating is hydrophilic and hydrophobic, respectively. It is possible to measure relative humidity from 0 to 100% in the temperature range 5÷50°C with the main relative error of 2.5 to 5.0%. The measurement error increases with repeated acts of sorption-desorption of vapors of the odes. Desorption is carried out using an inert gas pumped through the cell detection. The probability of the sensor to 0.92 for 2000 hours.
The method is implemented using the sensor "Wave" (figure 1), consisting of 1 - working piezoquartz resonator with a hydrophilic film coating electrodes; 2 - basic piezoquartz resonator with a hydrophobic film coating of electrodes; 3 - cell detection with a single input; 4 - generator self-oscillations of the resonators; 5 - shaper of the differential oscillation frequency of resonators; 6 - schematic of the frequency detection; 7 - amp analytical signal.
The sensor works as follows: from the generator self-oscillations of the resonators 4 pin 1 and reference 2 resonators signal with frequency ωcustomequal to the natural frequency of oscillation of the resonators. In the cell detection 3 use the dispenser enter the air sample. Due to the absorption of moisture from the hydrophilic film coating of the electrodes, the oscillation frequency of the resonator 1 is proportional to the concentration of water vapor in the sample and is Δω1=ωcustomω1The frequency of the reference resonator 2 is changed slightly due to related sorption of nonpolar compounds, pressure drops in the system when the input samples and is Δω2=ωcustomω2. The signal is s from the work 1 and the support 2 resonators come in shaper difference frequency 5,
which generates a harmonic signal of the oscillation of the two resonators
Regeneration films sorbents spend purge cell detection inert gases, such as hydrogen. The completeness of the regeneration of film coverings controlled by R is snasti frequency of oscillation of the working and reference resonators. Featured manufacturer of the desorption time is 16 minutes
The magnitude of the analytical signal Δω, accuracy, measurement range relative humidity, the range of operating temperatures depend on the characteristics of film coating of supporting and working resonators.
The disadvantage of this method is the inability of the measurements at low temperatures (<5°C) due to changes in characteristics of thin film coatings of the electrodes of the resonators. Another drawback of this method is the impossibility of accurately controlling the regeneration of film coating resonators, which greatly affects the accuracy of repeated measurements of relative humidity. This is because the installation device "on zero" is the difference of the frequencies of oscillation of the working and reference resonators, with a hydrophobic film coating of the electrodes of the reference resonator minor sorption of gases and even water vapor (see Kochetov JU Determination of volatile organic compounds in the gas phase using piezoscanner sensors based on synthetic and natural polymers: thesis(candidate of chemical Sciences: 02.00.02.- Saratov, 2002. - 143: ill. RSL OD 61 03-2/229-4).
The disadvantage is a long time desorption of water vapor from the amount of film coating. At Eisenia coating thickness leads to a decrease of the interval defined relative humidity: lower limit is limited by the sensitivity of film coating, the top is their low sorption capacity (see Kuzmenko T.A. application of the method of piezoquartz microinvasive in analytical chemistry. Voronezh: Publishing house of Voronezh state technology. Acad., 2001. - Pp.28-34).
The technical result of the invention is the measurement of relative humidity in a wide range of temperatures, including in the negative range, increased accuracy, reduced time of regeneration of film coating of the electrodes of the resonators.
The technical result is achieved by the fact that in the previously known method of measuring the relative humidity of the air, based on the measurement of the difference frequencies of the two resonators with frequencies of oscillation 9 MHz - working and reference electrodes are modified by various film coating is hydrophilic and hydrophobic, respectively, with further strengthening of the analytical signal and the regeneration of film coating with an inert gas, what's new is that there are three piezoquartz resonator with its own vibration frequencies 13-16 MHz, two of which are working with different hydrophilic film coatings, the properties of which are optimized to work in a certain temperature range, and one reference resonator without film coating that maintains a constant oscillation frequency; the device is equipped with a re what suchtelen working resonators.
The invention consists in that for the measurement of relative humidity from 0 to 100% in the temperature range (-20÷50°C applied three piezoquartz of the resonator natural frequency 13-16 MHz reference with a constant oscillation frequency, independent of changes in temperature and humidity, and two business SIC with different hydrophilic film coatings, sorption characteristics which are optimized to work in different temperature intervals.
The method can be implemented using the device (figure 2), including: 1a and 1B workers piezoquartz resonators with a hydrophilic film coating of the electrodes, sorption characteristics which are optimized for operation in temperature ranges from -20 to -3°C and from -3 to +50°C, respectively; 2 - basic piezoquartz resonator, sealed in the hermetic casing; 3 - cell detection with two inputs to each work resonator; 4 - generator self-oscillations of the resonators; 5 - driver differential oscillation frequency of resonators; 6 diagram of the frequency detection; 7 - power of the analytical signal; 8 - switch working resonators.
The method is implemented as follows: from the generator self-oscillations of the resonators 4 on one of the working cavities (1a or 1B depending on the ambient temperature, in the future 1 and reference 2 resonators signal with frequency ω customequal to the natural frequency of oscillation of the resonators. The choice of the working resonator in accordance with the specified temperature range is performed with the switch 8. The use of two ASMS with different properties of film coatings can measure relative humidity from 0 to 100% in a wide temperature range, including negative. Properties of thin film coatings (chemical composition, method of application, mass) is optimized for operation in temperature ranges from -20 to - 3°C for the resonator 1a; from 3 to 50°C resonator 1B.
The use of piezoquartz resonators with self-oscillation frequency 13-16 MHz increases the resolving power of the sensor in comparison with traditionally used resonators with the natural frequency of 9 MHz 6 times, according to the equation Sauerbrey, and 4 times in accordance with the experimental data (see Kuzmenko T.A., Kochetov GU, Silina J.E. and others, "Determination of trace hydrogen sulfide in the gas stream using phasedetector". Journal of analytical chemistry. - 2007. - So 62, No. 8.- S-874). This approach allows to reduce the weight (thickness) of film coating without reducing the sensitivity of microinvasive. The reduction of weight of film coating of the electrodes leads to a significant reduction in the time of desorption of water vapor from the volume of the sorbent and,therefore, the total time to determine relative humidity. Piezoquartz resonators with their own frequencies above 15 MHz to use is impractical because of the high sensitivity leads to uncompensated drift of the zero signal, and the determination of small concentrations of water vapor (0-5% relative) presents significant difficulties.
Through the entrance of the cell detection 3 to the appropriate worker resonator 1 via the dosing unit is the air sample. Due to the absorption of moisture from the hydrophilic film coating of the working electrodes of the resonator 1, its oscillation frequency is proportional to the concentration of water vapor in the sample and is Δω1=ωcustomω1. The frequency of the reference resonator 2 remains constant. Signals from desktop 1 and reference 2 resonators come in shaper difference frequency 5, which generates a harmonic signal of the oscillation of the two resonators similar to the prototype. The difference between the frequency of oscillation of the working 1 and reference 2 resonators can be written: Δω=Δω1-Δω2. Since the reference resonator is sealed in an air-tight casing, then its frequency will change slightly within the line of drift CRP: Δω2=ωcustom±3 Hz, then the analytic signal Δω=Δω1±3 Hz. The use of the reference resonator with a constant frequency of colemani which allows to reduce the error detection during regeneration the film coating of the electrodes and to a more accurate sensor "zero". The signal at the circuit of frequency of detection of 6, then the amplifier frequency oscillations 7. The definition of relative humidity and regeneration of film coating of the electrodes is conducted similarly to the prototype.
Comparison of some characteristics of the proposed technical solutions and the closest analogue is presented in the table.
|Comparative characteristics of technical solutions and prototype|
|Comparison parameters||Technical solution||Similar|
|The interval measured relativity humidity, % attributes.||0÷100||0÷100|
|Range of working temperatures, °C||1) -20÷3||5÷50|
|The natural frequency of oscillation of the resonator, MHz||15||9|
|Sensitivity microinvasive water vapor, Hz/ % attributes.||1)3,1||2,5|
|The relative error of measurement, %||1) 1,8-2,0||2,5÷5|
|The installation of the device "on 0" (regeneration time of film coating of sorbent), min||1) 12||16|
The proposed method of measuring humidity using three piezoquartz resonators with frequencies of oscillations 13-16 MHz, two of which are working CRP with different hydrophilic film coatings, and one reference CRP without film coating that maintains a constant oscillation frequency, allows you to:
- to expand the range of operating temperatures (-20÷50°C) measuring the relative humidity in the range from 0 to 100%;
to increase the sensitivity of microinvasive water vapor at positive temperatures;
to reduce the relative error of detection;
- reduce the time of regeneration of the sorbent and, therefore, the total time to determine the relative humidity of the air.
The method of measuring the relative humidity of the air, based on the measurement of the difference frequencies of the resonators is working and reference, followed by the rise analiticheskoj the signal and regeneration of film coating with an inert gas, characterized in that there are three piezoquartz resonator own frequencies 13-16 MHz, two of which are working with different hydrophilic film coatings, the properties of which are optimized to work in a certain temperature range, and one reference resonator without film coating that maintains a constant oscillation frequency, the device is equipped with a switch working resonators.
SUBSTANCE: method of measuring moisture content of transformer oil, where electromagnetic waves are excited in volume containing the analysed liquid. The reflected waves are then received and their power, as well as the temperature of the transformer oil is measured. A cooling element is further placed in the analysed liquid and local temperature of the oil near that element is measured. Further, temperature at which there is sharp rise in power of the reflected radiation, which occurs at the dew point, is then determined. Moisture content is then calculated using the formula: C(t)=(229.9+9.812*CA)*10(4.862-0.0182*C A )*(1-343/(t+273)), where CA is content of oil in aromatic hydrocarbons, %; t is the current dew point for moisture content of the oil C(t). Power of the reflected radiation is measured at low temperature of the analysed liquid and at an angle of 90° to the incident radiation.
EFFECT: high sensitivity of measuring moisture content of liquid materials with low moisture content.
4 cl, 1 dwg
SUBSTANCE: method comprises the following steps: selecting a substrate, weighing said substrate to find initial mass, preparing a mixture containing a measured amount of water and the analysed composition, immersing the substrate in the mixture, removing the substrate and draining excess mixture from the substrate, drying and weighing the substrate to obtain final mass, comparing the initial and final mass to determine the mass of residue stuck to the substrate.
EFFECT: determining how a composition will deposit on sanitary ware such as shower cabins, bath-tubs and wash basins.
8 cl, 2 tbl, 1 ex
FIELD: chemistry; measurement.
SUBSTANCE: detecting element of the sensor is one or several consoles with complex of specifically interacting molecules and biological bodies immobilised on the surface. Cantilever can de used as a detecting element for atomic force microscopy. Determination of one of the components is achieved thanks to static deformations measurement of micromechanical device, which are appeared as a result of immobilised complex dissociation and binding of other element by analyte. Invention ensures absolute sensitivity increase.
EFFECT: it ensures increase of sensor absolute sensitivity for qualitative analysis of chemical compounds and biological bodies.
6 cl, 1 ex, 2 dwg
FIELD: the invention refers for effective and optimal biocide processing of white water in cellulose-paper industry and for choosing of biocenonosis agents designed for struggle with sediments of polluting substances forming on the surfaces of various equipment.
SUBSTANCE: the mode and the arrangement are based on using analyzed sample which is sunk into a capacity and is fixed on a suspension connected with a weight sensor. The capacity has an arrangement for feeding into it of a studied liquid which streamlines the surface of the sample sunk into the capacity and during a definite period of time form in it sediments. Periodically through even periods of time liquid from the capacity is poured out, the analyzed sample is dried and weighted. According the difference of weight between two successive measurements the weight of sediments formed on the surfaces of the sample is defined. A computer connected with a weight sensor allows to analyze successiveness of received results and draw up graphics of changing in time of weight formed on the sample of sediments.
EFFECT: possibility of receiving trustworthy quantitative data about sediments of polluting substances during the whole period of tests.
17 cl, 1 dwg
FIELD: gas medium analysis.
SUBSTANCE: device can be used for analyzing qualitative and quantitative parameters of cigarettes, cigars and cigarillos containing volatile components. Multi-sensor device has detecting cell, which has in turn the reaction container to be subjected to thermostatting. Capacity of the container is 500 cubic centimeters. Device also has gas-carrier and sample input and output jacks. Reaction container has two cylindrical parts. Top part has removable mounted-in holder for 25 piezoelectric-quartz sensors. There is electronic control unit in the top part as well. Lower part has metal cigar or cigarette holder, air ventilator for removing concentration gradient of volatile matters from the whole space of space. Both parts are hermetically connected to each other.
EFFECT: improved precision.
1 tbl, 1 dwg
FIELD: measurement equipment.
SUBSTANCE: portion of controlled fluid is supplied to reservoir 1 through flow control 10 and inlet nozzle 2, which is heated by vapour generation of non-dissolved water. Acoustic waves occur at breakage of the cover with vapour, which are converted by means of acoustic receiver 5 to electric signals, which are supplied through amplifier 7 and counter 8 to indicator 11. Timer 9 controls counter 8 and flow control 10. Reservoir 1 is closed with cover plate 4, inside which cone insert 6 is located.
EFFECT: simpler design and higher measurement accuracy.
2 cl, 1 dwg
FIELD: oil and gas industry.
SUBSTANCE: method involves three main stages: sampling of fixed volume of oil product sample the temperature of which is measured; then, fixed chemical reagent volume is added to sample (sulphuric acid) and sample temperature change is measured; level of product water content is determined. First, relationship between oil product water content level and fixed oil product volume temperature increment level is determined at its interaction with fixed chemical reagent volume and calibration charts are built for further determination of oil product water content. Sulphuric acid is used as chemical reagent.
EFFECT: possibility of high-accuracy determination of oil product water content due to recording the parameters determining the oil product water content level; simplifying the set of devices required for implementation of the method.
2 cl, 2 dwg
SUBSTANCE: apparatus for measuring concentration of dropping liquid in a gas stream has a filter unit with a sampling probe. The apparatus also has a gas collection nozzle with a flow regulator and a guide cylinder. The apparatus also has gas metre with a manometer and a thermometer. The apparatus is also fitted with a manual gear-rope drive with a spring-loaded position regulator for the filter unit with the probe and a linear scale on the guide cylinder. The apparatus also has a display for displaying the current gas flow rate and a set of removable probes with a different inner dimension.
EFFECT: high measurement accuracy owing to ensuring isokinetic collection of gas samples and wide range of using the apparatus depending on pressure in the gas pipeline.
SUBSTANCE: amount of liquid which can be absorbed by leather fabric is determined in from moisture content at the moment of shrinkage of samples when joining together in percentages. The difference in moisture content and total volume of the liquid located between molecules and in fibrils is then calculated.
EFFECT: establishing moisture distribution on skin structural levels.
1 dwg, 5 tbl, 9 ex
SUBSTANCE: method of measuring gas humidity involves conversion of the measured quantity to a parametre of an electrical signal transmitted over a measurement channel and periodic correction of the graduated characteristic of the hygrometre. Gas, whose humidity is being measured, is isobarically cooled to temperature lower than the dew point, determined from previous measurement results. The obtained gas with precisely known humidity is used to correct the graduated characteristic of the hygrometre. After cooling the gas to temperature lower than the dew point and before feeding the gas onto the hygrometre sensor, temperature of the gas is raised to an initial value. Also, after isobaric cooling of the gas in order to measure humidity, cooling the gas continues until a second value of humidity is obtained at a precisely known temperature of the gas and correction of the graduated characteristic of the hygrometre is carried out based on the obtained two measurement values of humidity.
EFFECT: automation of correction of the graduated characteristic of the hygrometre during measurement and providing long-term stability of measurement errors.
3 cl, 1 dwg
FIELD: oil-and-gas production.
SUBSTANCE: method of measurement of dispersed phase carry-over includes passing through filter-mount of particular volume of gas samples with following definition of overweight of filter-mount ensured by deposition of dispersed phase. Additionally this volume of gas sample is bleed through bleeder probe. Extracted moisture is collected in additional filter-mount, additional filter-mount is overlapped. Particular volume of gas sample is directed to filter-mount during particular period of time at steady gas flow through installation, which provides regulator implemented in the form of block with set of standardise critical jet. Installation implementing method contains bleeder probe, filter-mount, additional filter-mount for collecting of extracted moisture, regulator of steady flow of gas at pressure, temperature and velocity in system of installation, equal to pressure, temperature and velocity of gas stream, implemented in the form of block with set of standardised critical nozzles.
EFFECT: receiving of more exact values of entrainment of discontinuous phase in gas flow.
2 cl, 1 dwg, 1 tbl
FIELD: electrical engineering.
SUBSTANCE: in water-cooled generator, gas is extracted in N points from generator volume, and measurement of humidity in all points of extraction, according to invention, is carried out with single metre of moisture concentration serially, value of humidity in N extraction point of knowingly driest gas is subtracted from results of current measurements in N-1 point of sample extraction, and speed of differential data variation is used to identify emergency water leaks.
EFFECT: invention provides for detection of emergency mode in water-cooled generators related to water leaks, reduced time required for detection of emergency mode.
FIELD: measurement equipment.
SUBSTANCE: device for measurement of air humidity comprises capacitance sensor of humidity (2), resistive temperature sensor (14), reference stable capacitor (20), high-resistance precision resistor (11), relay (13), the first and second normally closed contacts of relay (6, 22), the first and second normally open contacts of relay (7, 23), low-resistance precision resistor (12), reference high-precision resistor (21), AC voltage generator (1), line of AC voltage supply (8), metres of level of output signal from AC voltage amplifiers in capacitance sensor of humidity and resistive sensor of temperature (3, 4), source of relay supply (5), line of relay control (9), registrator (10), signal lines (15, 16), amplifiers of AC voltage of capacitance humidity sensor and resistive temperature sensor (17, 18), functional unit (19).
EFFECT: higher accuracy of air humidity measurement.
2 cl, 1 dwg
FIELD: physics, tests.
SUBSTANCE: invention is related to devices for testing of construction materials and may be used to detect moisture resistance of heat insulation materials of fibrous structure, in particular products of mineral wool. Device for moisture resistance testing of heat insulation fibrous material samples comprises untight chamber with detachable cover equipped with sources and controllers of water heating to boiling, inside of which there is a detachable meshy tray for installation of tested samples. Moreover, on detachable cover there is a standard instrument for detection of compressibility of fibrous heat insulation materials. Besides movable stem of standard instrument passes through detachable cover of untight chamber inside guide tube and rests on test sample via additionally introduced spatial frame, which eliminates distortions from effect of heat and moisture medium at sample in process of its moisture resistance testing, and on top and bottom of test sample, meshy gaskets are installed for even transfer of pressure to test sample.
EFFECT: development of device that has high efficiency in operation and improved authenticity of sample testing results.
5 cl, 1 dwg
SUBSTANCE: hygrometer includes cooling system, measuring chamber, temperature sensor, light source, photodetector, inlet and outlet manifolds, valves, pressure gauge, flowmeter and cooler. Cooling system includes flat groove recess parallel to the axis of the measuring chamber and the aperture thereover covered with shielding glass with light source above. According to the version 2, hygrometer comprises photodetector mounted together with light source. According to the version 3, hygrometer includes the second photodetector along the axis of the measuring chamber.
EFFECT: higher measurement accuracy of gas dew point and design simplification.
3 cl, 4 dwg
FIELD: measurement technology.
SUBSTANCE: electric insulating base, electric insulating substrate onto which moisture-sensitive coating is applied on the base of gelatin which has its external layer tanned, two plated electrodes which have contact surface to contact with moisture-sensitive coating on base of gelatin and measuring device connected to outputs of plated electrodes. Two clamping units are introduced into the device additionally. Any clamping unit intends for creating permanent pressure of corresponding plated electrode onto working surface of moisture-sensitive coating on base of gelatin. Layer of gelatin coating has uniform thickness. Contact surface of plated electrodes adjacent the moisture-sensitive gelatin-based coating is made to be oxidized and flat.
EFFECT: prolonged service life; higher stability of operation; increased moisture resistance.
5 cl, 1 dwg