SU818030A1

SU818030A1 - Resistive heating apparatus

Info

Publication number: SU818030A1
Application number: SU792798530A
Authority: SU
Inventors: Борис Константинович Орлов; Марк Борисович Гутман; Анатолий Григорьевич Грязнов; Владимир Львович Мальтер; Семен Моисеевич Штерман; Виктор Петрович Невежин; Владимир Михайлович Малышев
Original assignee: Предприятие П/Я Г-4696
Priority date: 1979-06-19
Filing date: 1979-06-19
Publication date: 1981-03-30

Description

(54) УСТАНОВКА РЕЗИСТИВНОГО НАГРЕВА(54) SETTING RESISTANT HEATING

II

Изобретение относитс к электротермии, а более конкретно к устройствам дл пита-, ни нагревателей сопротивлени , обладающих отрицательным температурным коэффициентом сопротивлени (ТКС), например изготовленных из стабилизированной двуокиси циркони .The invention relates to electrothermal, and more specifically to devices for power or resistance heaters with a negative temperature coefficient of resistance (TCR), for example made of stabilized zirconia.

Известно устройство дл питани нагревателей сопротивлени из стабилизированной двуокиси циркони 1.A device for supplying stabilized zirconia resistance heaters is known.

В этих устройствах затруднен запуск нагревателей , имеющих больщое сопротивление в холодном состо нии.In these devices, it is difficult to start heaters that have a large cold resistance.

Известыа установка резистивного нагрева , содержаща источник питани , к выходу которого подключены по меньщей мере два параллельно соединенных высокотемпературных нагревател с отрицательным коэффициентом сопротивлени , например из двуокиси циркони , а ко входу - снабженный задатчиком регул тор мощности, и по меньщей мере один дополнительный резистивный нагреватель предварительного разогрева , подключенный к выходу дополнительного источника питани 2.The known installation of resistive heating contains a power source whose output is connected to at least two parallel-connected high-temperature heaters with a negative resistance coefficient, for example zirconia, and to the input a power regulator equipped with a setting unit, and at least one additional resistive preliminary heater heating connected to the output of an additional power source 2.

При комнатной температуре окисный нагреватель не электропроводен, так как двуокись циркони при этой температуре вл етс диэлектриком. Дл того, чтобы нагреватель стал электропроводным, его разогревают с помощью нагревател предварительного подогрева до температуры 1200- 1300°С, при которой возможен его самосто тельный разогрев за счет пропускани через него электрического тока. Запуск окисного нагревател желателен с максимального напр жени , так как запуск с положенного напр жени возможен только при более высоком прогреве нагревател , что значительно усложн ет конструкцию печи или не выполнимо.At room temperature, the oxide heater is not electrically conductive, since zirconium dioxide is a dielectric at this temperature. In order for the heater to become electrically conductive, it is heated using a preheater heater to a temperature of 1200-1300 ° C, at which it can be warmed up independently by passing an electric current through it. The starting of the oxide heater is desirable from the maximum voltage, since starting from the applied voltage is possible only with a higher heating of the heater, which significantly complicates the design of the furnace or is not feasible.

Нагреватель из стабилизированной двуокиси циркони обладает малой термостойкостью , поэтому после его включени питающее напр жение необходимо уменьшить до величины, обеспечивающей скорость подъема температуры не более 4 град/мин.The stabilized zirconia heater has a low heat resistance, therefore, after it is turned on, the supply voltage must be reduced to a value that provides a temperature rise rate of no more than 4 degrees / min.

Claims

In the initial start-up period of oxide heating, the regulation is carried out manually, since at low currents regulation using the programmer is inefficient. The disadvantage of such a device is the impossibility of automatic activation of the oxide heater, since in the initial period manual adjustment is necessary. In addition, if the circuit contains several oxide heaters connected in parallel, then all of them can not be started from the maximum voltage of the power source. This is because the heaters start up as they warm up, the conditions for which are somewhat different for each of them. After starting the first heater, it is necessary to reduce the supply voltage due to the fact that its heating rate can significantly exceed the permissible (up to 400 deg / min). The decrease in voltage leads to the fact that the rest of the submersible guns must be heated to a higher temperature than the first one, and this will complicate the start-up process. The purpose of the invention is to provide the possibility of automatically turning on heaters with a negative TKS and starting all parallel-connected high-temperature heaters from the maximum voltage. This goal is achieved by the fact that a resistor shunted by the switching element is switched on in series with each of the resistors with negative TKS in the installation. The drawing shows the block diagram of the installation. The installation will hold the power supply 1, the voltage regulator 2, the setpoint with software device 3, heaters 4 with a negative temperature coefficient of resistance, additional resistors 5 with shunt elements 6, as well as a preheating system 7, the state of the heater 8, the source 9 power and control voltage 10. Device f works in the following way. Heaters 4 are energized at the maximum voltage of the power source and are preheated. In the initial period of ignition of a heater with a negative QC, its resistance is significantly greater than the resistance of resistor 5 and therefore the actual voltage of the power supply is applied to the heater. After starting the heater 4, its resistance decreases due to heating and the voltage of the power supply source is redistributed: on heater 4 decreases, and on additional resistor 5 it increases, which reduces heating rate of heater 4. Each heater 4 is heated to the temperature required for starting independently from each other, and the overheating of the heaters is excluded due to the current being limited by the resistor 5. After ignition of all heaters 4 connected in parallel, their further heating is transmitted to the software device y, wherein the additional resistance zakorachivayuts. In the proposed installation, it is possible to automatically start all heaters connected in parallel with the maximum supply voltage. The maximum heating rate of the heaters during their start is easily controlled by the value of the additional resistance and does not exceed the allowable. Claims of the Invention A resistive heating unit comprising a power source whose output is connected to at least two parallel-connected high-temperature heaters with a negative temperature coefficient of resistance and an input - a power controller with a setting device, and at least one resistive preheating heater connected to the output An additional power source, characterized in that, in order to increase the reliability of the installation by smoothly starting up the full voltage source of the high-temperature heaters, a resistor shunted by the switching element is connected in series with each of them. Sources of information taken into account in the examination 1. "Refractories, 1971, No. 12, p. 36-41.

2. Investigation of the performance characteristics of high-temperature oxide heaters and identification of their application areas. Report VNIIETO ONT 127.133, 1975.

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