Condensation high-temperature hygrometer

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

 

The invention relates to measurement devices, more particularly to a technique of measuring the humidity of gases and air. Such measurements are important when baking bread, Smoking, drying wood, bricks and many other processes.

Widespread hydrometers sorption type, the action of which is based on measuring the electrical resistance or the dielectric constant of the film of polymer material, depending on the amount of adsorbed moisture [1].

The disadvantages are their low operating temperature is 50-80°C, hysteresis and instability characteristics.

The best characteristics have sensors with sensitive inorganic layer of aluminum oxide [1]. However, this sensor is based on the determination of the dew point and therefore can only be used up to 100°C.

In U.S. patent No. 4057823 proposed as adsorption layer to use porous silicon [2]. On its surface are applied metallic interdigital electrodes, and the dielectric of the capacitor is essentially air, the volumetric content in porous silicon reaches 70-90%. Condensation of water, the dielectric constant of which is 80 times higher than air, leads to a change in capacity depending on temperature and relative humidity.

The disadvantages of the design are poverhnostnogo breakdown between closely spaced electrodes in conditions of high humidity and temperature, and low sensitivity, due to the fact that the electric field does not penetrate deep into the porous layer, where, first of all, and condensed moisture. In addition, a large total length of the electrodes (about 1 meter) results in high mechanical stresses due to the large difference in thermal expansion of the metal and silicon. Therefore, the sensor on porous silicon, performed according to [2] and we have adopted for the prototype, unsuitable for operation at elevated temperatures.

The technical result of the invention is the possibility of operation at high temperatures, increased sensitivity when operating at elevated temperatures, providing resistance to high temperatures and thermal Cycling.

The technical result is achieved in that the condensation hygrometer contains a layer of oxidized porous silicon monocrystalline substrate, the system of the interdigital electrodes and the metal contacts to it, while the pores in oxidized porous silicon are conical, extending to the surface shape, and the electrodes are insulated by the oxide which is made of polysilicon and embedded in the body of the single crystal substrate on the entire thickness of the porous layer.

The use of monocrystalline silicon in design allows you to easily manage the configuration of pores, mainly by changing the current density is the process of forming a layer of porous silicon [3].

The invention is illustrated in the drawing, which shows in plan and cut fragments of the invention: 1 - single-crystal plate, 2 - layer porous oxidized silicon, 3 - film SiO2, 4 - polycrystalline electrodes, 5 - metal contacts.

The novelty of the design lies in the fact that due to the conical shape of the pores, the degree of filling of the condensate varies, decreasing with decreasing humidity. Thus the curvature of the surface in the pores so high that condensation can occur at temperatures far above the boiling point. According to our experiments, the capacitor of the proposed design responds to the change of humidity, up to 300°C. It directly follows from equation Kelvin, according to which the vapor above the surface is inversely proportional to the radius of its curvature. It is also known that to remove the moisture remaining in the pores after receiving porous layer is possible only by prolonged heating at temperatures above 300°C in an atmosphere of inert gas or under vacuum conditions.

For measuring capacitance hygrometer was conducted by including it as a frequency control element standard RC-generator.

The present invention is implemented as follows. In the monocrystalline plate is Rennie plasma-chemical or chemical method mytravelguide grooves on the topology of the interdigital electrodes and the area to metal contact depth of about 10 μm. After thermal oxidation of the entire surface was thrasivoulos alloyed with polyctenium of a thickness exceeding 15 μm. Polysilicon, protruding above the grooves, zashlifovyvaetsja to thermal oxide than was provided by the formation of the polysilicon interdigital electrodes. Next, filled with polyctenium grooves covered by a layer of SiO2, which shaped boxes for metal contacts. The final operation was the formation of the single crystal ERP system special forms and oxidation of the entire structure, including the field day.

The tests were performed in an incubator with controlled humidity. The nominal value of the capacitance of about 100 pF. The transformation function was exponential in nature, with the greatest increase in capacity of around 50% from the initial value was observed with increasing relative humidity from 40% to 90%, which corresponds to the model of capillary condensation. The device can withstand thermal cycles "liquid nitrogen-600°" without changing the initial value of capacitance, the hysteresis of the main characteristics is negligible (less than 0.1% of the nominal value) due to the stability of the pore geometry.

Summarizing the above, we can conclude that the proposed invention can have a positive effect, because it means the emergence of the new generation devices based on the high technology of microelectronics and suitable for mass production.

Sources of information:

1. Al J. Sensors and measuring systems. World, 1995, Vol.2, str-341.

2. U.S. patent No. 4057823 (there is a translation in "Foreign electronic engineering", 1989, No. 9, p.12) prototype.

3. M.J. Schöning, A. Kurowski, M. Thust at al. Capacitive microsensor for biochemical sensing based on porous silicon technology. Sensors and Actuators B 64 (2000) 59-64.

Condensing high temperature hygrometer containing layer is oxidized porous silicon monocrystalline substrate, the system of the interdigital electrodes and the metal contact thereto, characterized in that the pores in oxidized porous silicon are conical, extending to the surface shape, and the electrodes are insulated by the oxide which is made of polysilicon and embedded in the body of the single crystal substrate on the entire thickness of the porous layer.



 

Same patents:

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

Hygrometer // 2219532
The invention relates to techniques for measuring the humidity of gases

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!