A method of measuring the level of grain or fodder in silos
(57) Abstract:Usage: in the temperature control systems and products stored in insulated tanks. The inventive exercise disposable pre-calibration readings of temperature-sensitive elements. Use these readings to adjust subsequent current values of the difference. This takes into account the scatter of the readings of temperature-sensitive elements. Preliminary measurement of temperature differences between the top, in the air column over the product, point and lower, are in the product, point. This difference is compared with the selected threshold for the test conditions to obtain reliable measurements. 1 Il. The invention relates to measuring technique and can be used for designing control systems level and temperature of grain or fodder stored in silos silos.Known methods and devices for measuring the level of solids stored in insulated tanks, based on the accommodation of pressure sensors, floats, temperature-sensitive elements, etc., and non-contact methods and devices based on subsequent measurements reflected from a surface of the waves.In particular, the known contactless radio-frequency method for measuring the surface environments, details of which are given in the description.with. N 1642250, CL G 01 F 23/28, 1980, in accordance with which directional sensing surface frequency-modulated waves of the microwave range, the reception of the reflected waves, their mixing with the probing waves and determining the frequency of beating of the resulting signal, when the signal delay of the beating and in each cycle of frequency modulation calculate the autocorrelation function of the signal beating on the time interval, the increase in the frequency of the probe and reflected signals in time delay varying from the specified minimum value until a zero value of the autocorrelation function. Time delay calculates the level of occurrence of the product to the source dimension.The disadvantages of the considered method are the complexity and limited application, because it is, first of all, ineffective for measurements in tanks large (25 to 30 m) high with large quantity of air layer, secondly, it is not possible simultaneously with the measurement to measure the temperature.the p on the determination of the resonant frequency of the generated oscillations, depending on the level of occurrence of the measured environment.The second analog inherent in the same technical shortcomings as the first.The closest entity and the technical result of the proposed method is a method performed by a device to control the level of high-temperature granular media, described ed. St. N 794384, CL G 01 F 23/22, 1978.The essence of this technical solution is that for level measurement in high-temperature granular media in a controlled point-of-tank product accommodate sensing elements with which they measure the temperature on the horizons of the reservoir, sequentially compare the temperature values at the two adjacent points and the results determine the level of occurrence of the substance in the tank.The method solves the problem of simultaneous measurement of level and temperature of high-temperature granular matter in the tank on the testimony installed thermosensitive elements, however, as it follows from the title, it is applicable only for level measurement in high-temperature granular media, giving a significant temperature drop at the boundary of the medium (air).In this case, the known technical solution or do not provide the solution for level measurement or solves it, but with significant errors.In addition, the variation in the readings of temperature-sensitive elements causes an error in determining the temperature difference between adjacent points, which degrades the accuracy of the level measurement at small temperature differences.These drawbacks are substantially reduced in the proposed method of level measurement.The essence of the proposed solution lies in the fact that in the method of level measurement based on the measurement using a temperature-sensitive element of the temperature in the n control points of the bins are evenly distributed vertically, and determining the temperature difference between adjacent points in i = ti-ti+1,, i 1-(n-1), pre-produced disposable determining and memorizing the differences in the readings of the adjacent heat-sensitive ele is UB>i-tTi+1,
and before each measurement level is determined by the temperature difference between the first, located directly under the roof of the silo, and the last points1,n= t1-tnand the temperature difference between the outside air and the last point0,n= to-tncompare the modules of the obtained values with the threshold value of1and continue the measurement process, and when and in the air space of the silo pump outside air, adjust the value of each temperature difference
compare the values of the modules sequentially from top to bottom with a threshold value of2fix the value ofKjthe first time exceeded its threshold, and then the value of Kj+1compare them with each other according to the rule "more", "less" and determine the level of products according to the formula
where Dh is the distance between adjacent control points.Thanks disposable pre-calibration readings of temperature-sensitive elements and use them to adjust subsequent current values of the difference takes into account the scatter of readings thermosensitive the temperature between the upper, in the air column over the product of the point and the bottom, in the product, point and comparing this difference with the selected threshold checks the conditions to obtain reliable measurements.When this condition is not fulfilled it is created artificially by forced injection of outside air in the upper cavity of the silo.The transition to the absolute values of the differences provides the ability to determine the level not only in cases, when the product temperature above the temperature of the air column in the silo, but in cases where it is lower. All this together provides increase as the reliability and accuracy of the level measurement.Theoretically, the maximum measurement error level of the proposed method is estimated as half the distance between adjacent control points.For example, when using Thermopolis Voronezh VCCB "pole" with a total length of 28 meters twelve thermosensitive elements, measurement error does not exceed one meter.The accounting ratios of the first two temperature differences exceeding the threshold allows you to specify the location of the boundary of two media regarding contrariwise drawing, where indicated:
1-1nthe sensing elements placed in the silo (TCE1-n);
the outer sensing element (NTCA);
3 block switching and signal transformation temperature-sensitive elements;
4, the computing unit;
Thermosensitive elements 11-1n(TCE) uniformly with constant step h is placed vertically in the silo. The sensing element 2 is installed outside of the silo and is designed to measure the outside temperature.As thermosensitive element 11-1n2 can be used commercially available temperature sensors. To obtain more reliable and accurate measurements it is desirable to use sensors with higher sensitivity.Unit 3 switching to the transform is used to alternately survey thermosensitive elements 11-1nand 2 in accordance with the program stored in the block 4, the conversion of input analog signals into digital form and issue codes in block 4.Unit 4 performs in accordance with the selected algorithm processing determining current differences i, the correction values according to the results predescu expression. Block 4 also under appropriate conditions generates a command to turn on the fan for blowing outside air into the silo.The block 4 may be implemented on the basis of commercially available microprocessors.The technical result from the implementation of the method is to achieve higher accuracy and reliability of measurement.In addition, one of the advantages of this method is that its implementation does not require specially set in silos additional sensors, because they can be used temperature sensors, which are already equipped with silo. A method of measuring the level of grain or fodder in silos, based on the measurement using a temperature-sensitive element of the temperature in the n control points of the silo, which are evenly distributed vertically, and determining the temperature difference between adjacent points in i = ti- ti+1, i 1oC (n 1), characterized in that the pre-produced disposable determining and memorizing the differences in the readings of the adjacent heat-sensitive items at a temperature T, the same for all temperature-sensitive elements Ti= tTi- tTi+1and before each and>- tnand the first point come directly under the roof of the silo, as well as the temperature difference between the outside air and the last point0,n= to- tncompare the modules of the obtained values with the threshold value of1and continue the measurement process, and when in the air space of the silo pump outside air, adjust the value of each difference of the readings ofKi=i-Ticompare the value of the modules sequentially from top to bottom with a threshold value of 2fix the value ofKjthe first time exceeded its threshold, and then the value ofKj+1compare them with each other on the module by the rule of "more", "less" and determine the level of product according to the formula
< / BR>where Dh is the distance between adjacent control points.
FIELD: measuring engineering.
SUBSTANCE: method comprises locating extremums of the profile of spatial gradient of the heat exchange coefficient of the distributed sensor of a meter for measuring temperature profile, which is provided with a built-in heater, by repeatable heating of the sensor and measuring the current profile of the heat exchange coefficient from the formula
where mc, and S are the parameters of the sensor (m is the mass, c is the heat capacity, and S is the area of the outer side), P(z,ti) and P(z,ti+1) are the values of heating power, and are the profiles of temperature measured by the sensor, and are the profile of temperature derivatives at time ti and ti+1, and calculating the current profile of spatial gradient of the heat exchange coefficient . The location of the interface is assumed to be the location of extremums at this profile. The current profile of the heat exchange coefficient is determined from the formula proposed.
EFFECT: enhanced accuracy of locating and expanded functional capabilities.
1 cl, 6 dwg
FIELD: measuring engineering.
SUBSTANCE: method comprises setting heating and non-heating thermistors of meters for measuring temperature profile, determining current temperature profiles, calculating current profile of heat exchange coefficients of the thermistors from the formula
where P(z,t) is the current power of heating of the thermistor at point z; m, c, and S are the parameters of the meters for measuring temperature profiles (m is the mass per unit length, c is the heat capacity, and S is the area of the outer side); is the current profile of temperature of the heating thermistor; is the current temperature profile of the non-heating thermistor, and calculating the current profile of the spatial gradient of the heat exchange coefficient . The location of extremums zm at the profile is assumed to be the location of the interface.
EFFECT: enhanced accuracy of locating and expanded functional capabilities.
FIELD: test engineering; measurement technology.
SUBSTANCE: indicator can be used as detector of presence of fluid in containers, in particular, in high-voltage discharge conduits of different purpose diesel engine. Indicator has housing, radiation source, reflector, radiation receiver and signal processing unit. There is working cavity in central part of the case. Reflector is disposed inside the cavity onto frame with two parallel channels. Radiation source is disposed in one channel and radiation receiver - in the other one. Radiation source and radiation receiver are connected with signal processing unit fastened to top part of plate. Plate is disposed inside case under frame. There hole for feeding fluid at lower part of side wall of working cavity. There is drainage hole in top part side wall of working cavity. Top cap of the cavity is made in form of screw. Frame is connected with case by thread.
EFFECT: simplified design; reduced cost.
FIELD: engineering of equipment for measuring height of liquid column in vessels filled with specific liquids, for example, sewage water.
SUBSTANCE: device for determining height of liquid column in a vessel includes vessel with pipe, measuring device and air feeding device. Also, one end of pipe is connected to air compressor, while another, open, one is provided with protective mesh and positioned inside the vessel near its bottom. Pipe is provided with locking valve and measuring device, for example, manometer, placed after the locking valve.
EFFECT: simplified construction, facilitated measurement of liquid column height.
FIELD: measuring technique; oil industry; chemical industry.
SUBSTANCE: method can be used for checking level of liquid in reservoirs, for example, at petrol stations. At least one measuring bar is placed in container; there are marks applied onto measuring bar. Image of measuring bar is transmitted by means of TV camera fixed to float (water-proof case of camera can be also made in form of float) through TV signal transmission channel to TV image introducing device and digital computing device, where calculation of level of liquid is performed on the base of digital representation of received original image. Float of waterproof case of TV camera made in form of float is capable of free movement in vertical direction when level of liquid changes. Signal received by TV camera does not depend on position (warps) of float as determination of level of liquid is performed on base of image of glowing areas on surface of light guide, which areas are disposed within field of view of camera. To perceive information, camera needs a small highlight, as camera is located close to measuring bar. When using light guides as measuring bars, highlighting is not required. Precision of result of measurement if defined by technological abilities of microscopic roughness application only with specified pitch onto surface of core of light guide and by resolution of chamber.
EFFECT: very high precision.
FIELD: control equipment.
SUBSTANCE: liquid level fiber-optic signaling device can be used for signaling on availability or absence of liquid inside area of measurement, which liquid is transparent for IR-radiation. Device has radiation source and receiver, feeding and removing optical fibers and sensitive element. The latter is made in form of rod having round cross-section; the element is made of optical transparent material, for which the following requirement is met: n0<nair.av<n1, where n0, nair.av and n1 are refractivity factor of liquid, air and rod correspondingly. Length L of rod is described by formula. R is radius of spherical segment of light-guide turned in the direction of media to be measured: 1,5dfe<=R<=2dfe, where dfe is diameter of envelope of optical fiber. R/L relation should meet specific conditions.
EFFECT: higher manufacturability of sensitive element's structure.
FIELD: measuring technique.
SUBSTANCE: liquid level meter comprises cylindrical housing (2) whose inner space is in communication with the liquid through passages (5). Float (10) mounted in housing (2) is coated with a mirror layer. Emitter (11) and receiver (12) of radiation are connected with the space of cylindrical housing (2) through optical switch (13) made of a disk provided with ports. The surface of the disk is coated with a reflecting layer. The optical switch has corner reflector. Unit (15) is connected with the emitter (11) and receiver (12) of radiation and drive (14) for rotating the optical switch. The liquid level meter is additionally provided with step cylindrical nozzle (6) having base (7) for fastening to the neck of the reservoir, second corner reflector, and glass baffle (8) that separates hollow cylindrical nozzle (6) into stages. The small diameter stage receives tube (1) provided with housing (2) of the liquid level meter. The ring space between the tube and the housing is closed by baffle (3) with reflecting layer (4) on its inner side to prevent a contact with the liquid. The large diameter stage of cylindrical nozzle (6) receives optical switch (13) one port of which receives the first and second corner reflectors. Emitter (11) and receiver (12) of radiation and drive (14) of optical switch (13) are mounted on base (7) of the step cylindrical nozzle (6).
EFFECT: enhanced precision.
SUBSTANCE: given sign of product is determined by means of the first method of measuring at which the first physical properties of the product are explored, in addition the given sign is determined with, at least, the second method of measuring which is grounded on the second physical properties which differs from the first physical properties, odds of values of the mentioned given sign gained by means of both methods of measuring are determined, and the mentioned odds of values are compared to the given threshold and in case the specified odds of values exceeds the specified threshold, solution on infringement of integrity of the mentioned yield is made.
EFFECT: increase of reliability of product integrity determination.
4 cl, 3 dwg
FIELD: instrument engineering.
SUBSTANCE: invention refers to control and measurement equipment and can be used for measurement (control) of liquid level in reservoirs. Essence of invention: level gauge includes vertically oriented transparent tube (1) that communicates with controlled reservoir. Float (8) with light source (7) located in this tube forms narrow round (0.2÷0.3 mm) laser beam at some angle α. Round translucent tube there are long flat (planar) beam guides (9) that have two layers. The first layer forms dense semi translucent mirror coating (mirror is inside of beam guide). The second coating layer - light-tight - is complete coating from 3 sides of beam guide that forms cross line code screens (10) from the 4th side. On the one end of beam guides there are photosensors (photodiodes) (5) connected to decoders (3) with digital output through sharpener-amplifiers (4). Float light source (7) is fed by power transformed by high-frequency generator the output circuit (12) of which is wound over beam guide code sensors.
EFFECT: liquid level non-contact measurement, flow metre readings output is performed in digital form to indicators (2) that can be transmitted to computer (1), for instance for production of liquid level dynamic measurement (or pressure drop).
SUBSTANCE: invention relates to electrothermics field, particularly it concerns to regulation of process variables at manufacturing of fused phosphates, calcium carbide in ore-thermal furnaces and can be used in non-ferrous metallurgy. Regulation method of melt level in bath of ore-thermal furnace includes regulation of phase voltage and electrode current. Additionally it is measured value of constant component of phase voltage, and level of melt at specified value of current is defined according to formula: H=K*Ucc, where H - melt level, mm; Ucc - value of constant component of phase voltage, mV, K - coefficient, depending on value of phase voltage, mm/mV.
EFFECT: achievement of high accuracy of measurement.
1 dwg, 1 tbl, 1 ex