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Section 9. Technical sciences
Tashmatov Xayit Karshiyevich, Tashkent state technical university, Ph. D., candidate of Technical sciences, the Faculty of Power engineering E-mail: [email protected] Muzafarov Anvar Rustamovich, Tashkent state technical university, student, the Faculty of Power engineering E-mail: [email protected]
Heating systems for the control of liquid level
Abstract: This article discusses the prospects of the application of heat gauges for the control of liquid level, it is proposed to develop the design of the heat of the water level transducer and provides static characteristic.
Keywords: transmitter, reliability, efficiency, heating systems, design, drive, equipment, fault.
Level measurement — a fairly common measurement process in hydropower, irrigation and drainage, oil refining, petrochemical, chemical, and other industries. Sometimes the results of measuring the level of judging the volume amount of the substance contained in the tanks (tanks, cisterns, tanks, etc.). For this purpose, a constant or measured capacitance (height) cross section (e. g., cans dimensional volumetric flow units), no special calibration table assigning to each current value of the level value of the tank volume.
Level gauges — absolutely necessary equipment in modern industry and technology. there are so many of today gauges, with different features, for a variety of materials, the level of which must be measured and controlled. And the most significant difference between the different gauges — this technology and how they work, which is also dependent on the use of instruments, their quality, cost and availability. Known liquid level gauges do not fully meet modern standards for simplicity, reliability, accuracy, efficiency and technological design [1]. Therefore research and development of highly reliable liquid level gauges is a very urgent task. Among the water level transducers still not investigated and implemented are thermal converters, which have a number of good qualities (sensitivity, simplicity of design, and others). And corresponding structural refinement can be successfully applied in practice.
Thermal control method is one ofthe main types ofnon-destruc-tive testing in liquids. Due to ease of manufacture, the signal processing speed and noise immunity of the pre-emptive use in monitoring and control systems received thermal transducers liquid level.
Figure 1 is a schematic structural diagram of a liquid heat level gauge [2].
Fig. 1. Schematic diagram of the heat gauge constructive liquid level gauge
The liquid level which is measured immersed heated heating element 1 cylinder 2 and comparative cylinder 3. The inner cylinder cavity filled with the same working fluid (liquid or gas).
The heating element 1 is powered by an external source of stabilized voltage. As a secondary device used manometer 4, which chamber capillary tubes are connected to the internal cavities of cylinders 2 and 3.
At a constant liquid level and switched on the heating element in the cylinders is set for some of the working fluid pressure is determined by the capacity of the heater, the volume of fluid in the cylinder, as well as the properties of the working fluid filling the cylinders.
When changing the liquid level change conditions of heat transfer and consequently the temperature and pressure inside the cylinder. The differential pressure in a heated and Comparative cylinders proportional to the level of liquid and measured differential pressure gauge 4, which is calibrated in terms of the level.
Using the appropriate Differential pressure relay elements can operate in alarm mode, and automatic control.
.¿4
Fig. 2. Scheme of the heat level converter design
The authors have developed a thermal water level inverter [3]. Example ofthe heat level converter design is shown in Fig. 2. The basic construction elements are two copper wires, a resistance R1 and a diameter of an order of magnitude less than the diameter of the other wire having a resistance R2 Wires with resistance R1 serves as a primary sensing element, and a resistance R2 — compensation. These wires are wound with a certain pitch on the dielectric frame 2 having a shape of a plate or a cylinder, which is distributed along the entire measured liquid level 1. Resistance R1 and R fixed resistors R3 and R4 are included in the adjacent shoulders of the measuring bridge
The method of determining the energy-efficiency of career excavators of the mining industry
circuit to which the output is usually connected normalizing amplifier NA and display device information DDI.
The output voltage of a bridge measuring circuit can be represented as:
K
UBHX = UM (K + s , (l)
where: £ — relative change in resistance R1 shoulder; K = R3/R4 — bridge coefficient symmetry; UM — voltage bridge circuit. Values of £ is determined from the formula:
1 + g q«c L - q«c
1 + - q«c - q«c
-1
(2)
where: q — heat flux; H — level full range of level changes; h — the current level; gx, gr — respectively the heat transfer coefficients of the wire in a liquid medium and gas; a0 — temperature coefficient of resistance of the wire material.
Analysis ofthe expression (1), (2) and the graph in Fig. 3. Show that for small values of e static characteristic linear enough.
Studies have also shown that the development level of thermal converters for hydraulic systems, it is advisable to perform them on the basis of the basic modular structure (see. Fig. 2), represents the dielectric nonconductor cylindrical rod, the entire length is a definite step wound copper wire with resistance R and R2 heat level converter. This design is placed in a perforated protective cover [4].
Fig. 3. Static characteristic heat level converter The developed design of the thermal water level converter has been tested during the monitoring and control of water level in the vertical drainage wells [5]. Maximum measurement depth reached 6 m; error of not more than 0.5 % of the upper limit; power consumption 10 W.; the water temperature is 5 °C - 25 °C.
It should be noted that the proposed liquid level gauge has a simple structure, fabrication of the device does not require high material costs. A distinctive feature of the transmitter is reliability, for its operation does not require special training of the staff.
References:
1. Ташматов Х. К. Устройство и приборы для регистрации максимальных и минимальных уровней воды в гидроузлах//Молодой ученый. - 2016. - № 2. - С. 238-241.
2. А. С. № 315945 Тепломанометрический уровнемер жидкости/Р. К. Азимов, Е. И. Гуревич, Е. А. Соколовский и В. С. Андрю-щенко//Опубл 01.10.1971. Бюл. № 29.
3. Ташматов Х. К. Тепловой преобразователь уровня воды//Датчики и системы. - 2006. - № 3. - С. 41-42.
4. Патент UZ. №IAP 04560. Тепловой преобразователь уровня жидкости/Ташматов Х. К., Азимов Р. К., Маматкулов Д. А.//Опубл. 2012. Бюл. № 8.
5. Tashmatov X. K. Heat liquid level sensor//European applied science. - 2016. - № 1. - P. 64-68.
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Kamalov Tolyagan Sirajiddinovich, Doctor of Technical Sciences, Professorr Institute of Power Engineering and Automation of the Academy of Science of Uzbekistan E-mail: [email protected] Toirov Olimjon Zuvurovich, Ph. D., Senior Researcher, Institute of Power Engineering and Automation of the Academy of Science of Uzbekistan E-mail: [email protected]
The method of determining the energy-efficiency of career excavators of the mining industry
Abstract: The composition of electrical equipment is determined, taking into account the efficiency of the constituting participating in the execution of each operation a complete cycle of operation (pressure, lifting, turn taking into account the reverse and move) for career excavators. A method of calculating the power consumption of career excavator calculation and analytical methods based on given values of the efficiency of each component of the electrical equipment and machinery in general is developed with the known value of their efficiency and power consumption of the actuating mechanism (pressure, lifting, turn taking into account the reverse and move). Calculation-experimental method is based on measurement results of
