Method of determining concentration of water fractions

FIELD: food industry.

SUBSTANCE: method comprises grinding the dump specimen of the agent in the thermograph by heating that is accompanied by its drying, obtaining a temperature curve of the agent, and determining the concentration of water fractions from the temperature curve.

EFFECT: reduced time consumption and enhanced reliability.

1 dwg

 

The invention relates to a method of determining the amount of water fractions, characterized by the binding energy of moisture from a substance, and can be used when choosing the method and drying conditions, and to study the drying process in the food and other industries.

There is a method of determining the amount of water fractions, characterized by the binding energy of moisture from a substance on the basis of the analysis of the isotherm sorption and desorption of this substance, obtained by placing the samples in a gaseous environment with the given relative humidity and temperature and incubation of the samples in this environment until a state of equilibrium, the amount of water fractions, characterized by different values of the energy and communications of moisture from the material, determined by the same type of plots on the curve sorption or desorption (Ginzburg, A.S., IM Savin Massivegalleries characteristics of food: a Guide. - M: Light and food industry, 1982, s.43-59, 280 S.)

However, the known method does not allow to obtain reliable information on the number of water fractions, characterized by the binding energy of moisture from the material along the curve sorption - desorption due to the long duration of the experiment, which in some cases can be more than 30 days, which leads to changes in the properties and composition of the material. In addition to the, the processes of adsorption and desorption are isothermal and equilibrium that differs significantly from the actual drying process, and there is also difficulty in obtaining accurate information when humidity is more than 85%.

There are also known methods for determining the quantity of water fractions in the substance, which consist in heating the sample in a thermal device with building thermal image in the form of curves of differential scanning calorimetry DSC, differential thermal analysis (DTA), or thermogravimetry. The aqueous fractions determined by the amount of exothermic peaks in the DSC curves or DTA or the number of stages (the kinks) on thermogravimetry (Ponomarev E Analytical chemistry in two parts. - M.: Higher school. 1982. Part 2. Qualitative analysis, s-261). However, the exothermic peaks are clearly recorded on the curves DTA and DSC, if the water fraction is removed in different temperature ranges and, consequently, significant differences in the binding energy of moisture from a substance.

Of these methods the closest to the technical essence and the achieved effect is way thermographic analysis of the types of communication moisture from the substance of the proposed F Kazan (Ginzburg, A.S. basic theory and techniques of drying food. - M.: the Food industry. - 1973, s.43-46),including registration material temperature in time in the slow process of drying a thin sample of material at a constant temperature of the drying air. On the thus obtained curve of the sample temperature from the time the water fractions determined by the number of identical sites.

However, the boundaries of adjacent similar areas on thermogram F Kazan for fractions, which differ by a small value of the binding energy of moisture from the substance are fuzzy and hard to identify. This significantly complicates the determination of the number of water fractions and values of moisture content of a substance corresponding to the boundaries of different water fractions.

An object of the invention is to improve the reliability and accuracy of determination of the quantity of water fractions, characterized by the binding energy of moisture from a substance.

This object is achieved in that in the method of determining the amount of water fractions, characterized by the binding energy of moisture from a substance, which consists in testing the crushed wet sample in thermographic device by heating, followed by its drying, to obtain thermograms of the substance and measuring the amount of water fractions, characterized by the binding energy of moisture from the substance, the characteristic kinks in the curve of thermogram, which characterizes the change in temperature of the sample during the test, what is new is that as thermographic devices use the der is fotograf, and the amount of water fractions determined by the same type of plots on derivative thermogravimetric curve, the value of the moisture content of the material corresponding to the intervals of the water fractions, calculated by the formula

,

where Uithe moisture content of the material, corresponding to the end/beginning of the same area on derivative thermogravimetric curve, kg moisture/kg dry matter; M is the amount of moisture in the sample, equal to the amount of moisture throughout the time of analysis is determined by thermogravimetric curve, mg; ΔGi- quantity evaporated from the sample moisture, corresponding to the end/beginning of the same area on derivative thermogravimetric curve, mg; G - weighed sample, mg.

The technical result is to increase the reliability and accuracy of determination of the quantity of water fractions in the substance other than the binding energy of moisture with a dry part of the substance.

Consider the process of dehydration crushed wet sample in thermographic device. Let us write the equation for the rate of change of the mass of the substance (drying speed)

where α - the degree of transformation of matter; A - coefficient; f(α) is a function of the degree of conversion of the substance; R - universal gas at the constant; T is the absolute temperature; E is the activation energy.

The activation energy is equal to

where r is the heat of vaporization of free (not bound) water; FStthe binding energy of moisture from a substance.

From equations (1) and (2) shows that the derivative thermogravimetric curve (DTG) has a greater sensitivity to the change in energy due to the moisture from the substance than thermogravimetry because it is influenced by both the temperature of the substance and the magnitude of the binding energy. If you place the crushed sample wet substances in thermographic device, for example in a furnace derivatograph, and heat the oven at a constant speed, when the evaporation of water molecules one faction will be the same type DTG curve. When the energy change due to the moisture from the substance of the DTG curve will also change.

The drawing shows derivatograph casein, taken in the following mode: the humidity of the sample WH=56%; the addition of sample G=0,300 g; sensitivity: DTA =1/3; DTG=1/10; TG=200 mg; heating rate of the furnace 5°C/min; analysis time of 50 minutes

Derivatographic way analysis of types of communication moisture from the material as follows.

First take a finely ground sample of moist material and put it in a furnace (maximum temperature which sostav the em 1050° C) derivatograph, for example, the system Paulik-Paulik-erdey in which the recording curves of temperature change of the sample, the decrease of the mass and velocity decrease its mass is photosamerican.

The result is derivatograph material in the form of graphic registration of the change of sample temperature, decrease of the mass and velocity of the mass loss of time in the drying process of the sample material in conditions close to real conditions of drying in an industrial machine.

Then the amount of water fractions and the corresponding value of the moisture content of the sample determined by the same type of plots on derivative thermogravimetric DTG curve, the value of the moisture content of the material corresponding to the intervals of the water fractions, calculated by the formula

,

where Uithe moisture content of the material, corresponding to the end (beginning) of the same area on derivative thermogravimetric curve DTG, kg moisture/kg dry matter; M is the amount of moisture in the sample, equal to the amount of moisture throughout the time of analysis is determined by thermogravimetric curve (TG, mg; ΔGi- quantity evaporated from the sample moisture, corresponding to the end (beginning) of the same area on derivative thermogravimetric curve DTG (mg; G - weighed sample, mg.

Way explains who I am as an example

For example derivatographic way analysis of types of communication moisture from the material, as the sample used casein.

A portion (0.3 g) analyte (casein) take one platinum crucible, and a portion of the reference sample to another. Alumina (standard) is weighed with an accuracy of up to ±5%. Both crucible installed in the device at the ends of the vertically standing porcelain tubes. Crucibles covered with quartz glass and lower the furnace so that the glass was in the middle of the furnace. Turn the drive program management set the initial voltage of 60 V and the rate of increase of the voltage set on division 50 minutes This will ensure that the heating rate is 5°/minutes Set the sensitivity of the galvanometer DTG - 1/10, a DTA - 1/3. The limit of measurement of the galvanometer T put on a final temperature of 500°C. the drum is charged (in red light) the light-sensitive photographic emulsion layer outside, close the drum cover, set in derivatograph and shut the neck of the instrument cover. Set zero position light pointers: galvanometer T is the ambient temperature, the galvanometer DTA in the middle of the temperature scale, DTG - reached 30-40 mm from the right cone of dark scales.

After derivatograph will be prepared to test, desireyou scales, connect gall is anomer DTG, the handle of the drum set to the zero position, light engines voltage regulator and recording devices. Include oven and light bulb TG, DTG, T and DTA.

Thus the uniformity of the heating furnace is provided by program control that is installed on speed 5°C/min

Curves are recorded by derivatograph as a function of the determined values from time to time.

The experiment ends upon completion of all measurements. After that, switch off the engine of the recording drum and voltage regulator, heating, lighting lamps and galvanometer DTG and cage scales. Next, raise the oven and the recording drum are removed from device. After processing of the photosensitive paper are derivatograph casein (the drawing), which is subjected to the following analysis.

On derivative thermogravimetric curve DTG (drawing) it is possible to allocate five sections, corresponding to different water fractions, each of which corresponds to the specified moisture content and different values of the binding energy of moisture from the product.

Let us determine the value of the moisture content of the material at point a:

Let us determine the value of the moisture content of the material at the point In:

Let us determine the value of the moisture content of the material at the point:

Let us determine the value of the moisture content of the material at the point D:

The first section, which is observed by reducing the moisture content to 1,225 kg/kg, characterized by the destruction of mainly free of moisture. The second plot corresponds to the moisture content in casein from 1,225 kg/kg to 0,545 kg/kg. the Third phase corresponds to the moisture content from 0,545 kg/kg to 0,227 kg/kg. Fourth section corresponds to the moisture content from 0,227 kg/kg-0,058 kg/kg. the Beginning of the fifth plot corresponds to the moisture content 0,058 kg/kg, which largely characterized monomolecular-linked by moisture in the casein.

The value of moisture content 0,058 kg/kg close to the value of a monomolecular layer of skim milk powder (0.03 kg/kg), which is designed Mckerron by BET method (Ginzburg A., Savin IM Massivegalleries characteristics of food: a Guide. - M: Light and food industry, 1982, p.55, 280 S.).

The advantages of the described method known before is that the experiment is close to the actual drying processes, and the dehydration of the material in the furnace of derivatograph enables many times to reduce the duration of the experiment, as well as improving the accuracy and reliability of measurements.

The obtained information can be used when choosing the method of drying product and technical devices for their implementation.

The method of determining the amount of water fractions, characterized by the binding energy of moisture from a substance, which consists in testing the crushed wet sample in thermographic device by heating, followed by its drying, to obtain thermograms of the substance and measuring the amount of water fractions, characterized by the binding energy of moisture from the substance, the characteristic kinks in the curve of thermogram, which characterizes the change in temperature of the sample during the test, characterized in that as a thermographic device using derivatograph, and the aqueous fractions determined by the same type of plots on derivative thermogravimetric curve, the value of the moisture content of the material corresponding to the intervals of the water fractions, calculated according to the formula

,

where Uithe moisture content of the material, corresponding to the end/beginning of the same area on derivative thermogravimetric curve, kg moisture/kg dry matter; M is the amount of moisture in the sample, equal to the amount of moisture in the entire period of analysis, determined by thermogravimetric curve, mg; ΔGi- quantity evaporated from the sample moisture, corresponding to the end/beginning of the same area on derivati the Noah thermogravimetric curve, mg; G - weighed sample, mg.



 

Same patents:

FIELD: measuring equipment engineering.

SUBSTANCE: condensation hygrometer contains a layer of oxidized porous silicon on mono-crystalline substrate, a system of opposite-pin electrodes and metallic contacts to it. Pores in oxidized porous silicon have conical shape, expanding towards surface, while electrodes, isolated by oxide, are made of poly-silicon and are embedded into body of mono-crystalline substrate for whole thickness of porous layer.

EFFECT: provision of possible operation at high temperatures, increased sensitivity during operation at high temperatures, increased resistance to effect of high temperatures and thermo-cycling.

1 dwg

FIELD: measurement engineering.

SUBSTANCE: moisture is extracted from moisture-containing organic material, for example, from timber. Device is used which has pressure-tight chambers for removing moisture, carriages for loading organic materials, moisture collectors and heat lines. Weight of removed moisture in relation to weight of organic material is calculated.

EFFECT: reduced time of procedure; increased precision of testing.

3 cl, 5 dwg

FIELD: atomic power engineering; registration systems of leaks of the heating carrier of the 1-st loops of the reactor facilities of nuclear electric power plants.

SUBSTANCE: the invention is pertaining to the field of atomic power engineering and may be used in at the reactor installations with the water-to-water and water-graphite reactors, in particular, at a decompression of the 1-st loop. The registration system of leaks of the heating carrier of the 1-st loops of the reactor facilities of a nuclear electric power plant contains a block of the controlled rooms with equipment of the 1-st loop of the reactor installation connected through air ducts of exhaust ventilation with a block of the channels intended for measuring of relative humidity of the air in the controlled rooms, that includes a reference channel intended for measuring of relative humidity of outdoor air in the rooms with the measuring channels. Sensor units of measuring channels are connected to a control unit for recording and matching of the parameters of the relative humidity of the air in the controlled rooms and in the room with the measuring channels, each of which is made in the form of an expander, on one butt of which there is a branch pipe with a filtering tool connected with the air duct, and on the other butt there is a flange intended for mounting of a sensor. At that outside of the expander there is a cooling chamber. The invention allows to simplify the process of the control over the indications of the relative humidity of the air in the controlled rooms and to improve reliability of operation of the reactor installation by well-timed detection of a location and intensity of the leakage of the heating carrier.

EFFECT: the invention ensure simplified control over the indications of the relative humidity of the air in the controlled rooms, improved reliability of the reactor installation operation by well-timed detection of a location and intensity of the heating carrier leakage.

6 cl, 9 dwg

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

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

The invention relates to techniques for measuring

The invention relates to measuring equipment

The invention relates to measuring equipment

The invention relates to a technique of measuring the

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

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

FIELD: atomic power engineering; registration systems of leaks of the heating carrier of the 1-st loops of the reactor facilities of nuclear electric power plants.

SUBSTANCE: the invention is pertaining to the field of atomic power engineering and may be used in at the reactor installations with the water-to-water and water-graphite reactors, in particular, at a decompression of the 1-st loop. The registration system of leaks of the heating carrier of the 1-st loops of the reactor facilities of a nuclear electric power plant contains a block of the controlled rooms with equipment of the 1-st loop of the reactor installation connected through air ducts of exhaust ventilation with a block of the channels intended for measuring of relative humidity of the air in the controlled rooms, that includes a reference channel intended for measuring of relative humidity of outdoor air in the rooms with the measuring channels. Sensor units of measuring channels are connected to a control unit for recording and matching of the parameters of the relative humidity of the air in the controlled rooms and in the room with the measuring channels, each of which is made in the form of an expander, on one butt of which there is a branch pipe with a filtering tool connected with the air duct, and on the other butt there is a flange intended for mounting of a sensor. At that outside of the expander there is a cooling chamber. The invention allows to simplify the process of the control over the indications of the relative humidity of the air in the controlled rooms and to improve reliability of operation of the reactor installation by well-timed detection of a location and intensity of the leakage of the heating carrier.

EFFECT: the invention ensure simplified control over the indications of the relative humidity of the air in the controlled rooms, improved reliability of the reactor installation operation by well-timed detection of a location and intensity of the heating carrier leakage.

6 cl, 9 dwg

FIELD: measurement engineering.

SUBSTANCE: moisture is extracted from moisture-containing organic material, for example, from timber. Device is used which has pressure-tight chambers for removing moisture, carriages for loading organic materials, moisture collectors and heat lines. Weight of removed moisture in relation to weight of organic material is calculated.

EFFECT: reduced time of procedure; increased precision of testing.

3 cl, 5 dwg

FIELD: measuring equipment engineering.

SUBSTANCE: condensation hygrometer contains a layer of oxidized porous silicon on mono-crystalline substrate, a system of opposite-pin electrodes and metallic contacts to it. Pores in oxidized porous silicon have conical shape, expanding towards surface, while electrodes, isolated by oxide, are made of poly-silicon and are embedded into body of mono-crystalline substrate for whole thickness of porous layer.

EFFECT: provision of possible operation at high temperatures, increased sensitivity during operation at high temperatures, increased resistance to effect of high temperatures and thermo-cycling.

1 dwg

FIELD: food industry.

SUBSTANCE: method comprises grinding the dump specimen of the agent in the thermograph by heating that is accompanied by its drying, obtaining a temperature curve of the agent, and determining the concentration of water fractions from the temperature curve.

EFFECT: reduced time consumption and enhanced reliability.

1 dwg

FIELD: analytical chemistry.

SUBSTANCE: method includes using static "electronic nose", whose matrix is formed from 2 weight-sensitive piezo-sensors, whose electrodes are modified by even application of film of acetone solutions of polyethylene glycol PEG-2000 and polyvinylpyrrolidone, and subjected to drying. Modified weight-sensitive piezo-sensors are fixed in holders on cover and put in bode of static "electronic nose". Completeness of removal of free solvents from films is controlled by constancy of fluctuations of weight-sensitive piezo-sensors, then sample of stock cube, dry bouillon or soup base is taken, heated, crushed thoroughly and mixed, placed into weighing bottle with polyurethane membrane on cover. Sample is kept in weighing bottle during 10-15 minutes. After saturation of gas phase with water vapours through polyurethane membrane sample of equilibrium gas phase is taken with 3-5 cm3 syringe, which is quickly injected into body of static "electronic nose". Frequency of fluctuations of weight-sensitive piezo-sensors is fixed, total analytic signal is formed in form of kinetic "visual print" and is compared with standards. Area of figure S"в.а" is calculated and humidity of sample ω % is determined using calibrating diagram drawn in coordinates S"в.а"=f (ω, wt %).

EFFECT: high expressiveness, reliability, accuracy, objectivity and simplicity of determining.

3 dwg

FIELD: physics.

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: 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

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

Up!