SU832345A2

SU832345A2 - Level indicator

Info

Publication number: SU832345A2
Application number: SU792805803A
Authority: SU
Inventors: Анатолий Владимирович Панин; Вячеслав Васильевич Захаров; Олег Федорович Кириченко; Роман Владимирович Колосов; Борис Борисович Рукас
Original assignee: Ворошиловградский Филиал Института"Гипроуглеавтоматизация"; Днепропетровский Завод Шахтной Abto-Матики
Priority date: 1979-07-09
Filing date: 1979-07-09
Publication date: 1981-05-23

Description

(54) СИГНАЛИЗАТОР УРОВНЯ(54) LEVEL SIGNALIZER

II

Изобретение относитс к области контрол уровн сыпучих материалов и жидкостей и может быть использовано в горной , нефт ной, химической и других отрасл х промышленности.The invention relates to the field of controlling the level of bulk materials and liquids and can be used in the mining, petroleum, chemical and other industries.

По основному авт. св. № 516907 известен сигнализатор уровн , содержащий электродный датчик с охранным кольцом, электронное реле с задержкой на срабатывание , блок сравнени посто нных напр жений , два параметрических стабилизатора , резистивный делитель, установленный на входе блока сравнени посто нных напр жений 1.According to the main author. St. No. 516907 is well known a level indicator comprising an electrode sensor with a guard ring, an electronic relay with a response delay, a DC voltage comparison unit, two parametric stabilizers, and a resistive divider mounted at the input of the DC voltage comparison unit 1.

Недостатком известного устройства вл етс низка надежность контрол сыпучих материалов с низкой электропроводностью в услови х большой запыленности и влажности, вызванна снижением эффективности действи охранного кольца и по влением дополнительной паразитной утечки за счет покрыти изол торов датчика уровн вместе с охранным кольцом слоем пыли, что приводит к самопроизвольному измерению заданных значений порогов срабатывани и отпускани сигнализатора уровн от изменени сопротивлени утечки .между электродол датчика и корпусом бункера , и соответственно вызывает или его ложное срабатывание или его неотключение при отсутствии контакта электрода с контролируемой средой.A disadvantage of the known device is the low reliability of monitoring bulk materials with low electrical conductivity under conditions of high dustiness and humidity caused by a decrease in the effectiveness of the guard ring and the appearance of an additional parasitic leakage due to coating the level sensors with insulators together with the guard ring. spontaneously measuring the setpoints of the thresholds for triggering and releasing the level indicator from a change in leakage resistance between the electrode electrode and to rpusom hopper, and accordingly causes false positive or Failure to disconnect or absence of contact of the electrode with a controlled environment.

Цель изобретени - повышение надежности сигнализатора при контроле уровн сыпучих материалов с низкой электропроводностью .The purpose of the invention is to increase the reliability of the detector when monitoring the level of bulk materials with low electrical conductivity.

Поставленна цель достигаетс тем, чтоThe goal is achieved by the fact that

в сигнализатор уровн дополнительно введены два резистивных делител , один из которых установлен между средней точкой параметрического стабилизатора и его плюсовым зажимом, а второй - между выходом и вторым входом блока сравнени посто нных напр жений, при этом средн точка первого резистивного делител соединена со вторым входом блока сравнени посто нных напр жений, а средн точкаTwo resistive dividers are additionally introduced into the level indicator, one of which is installed between the middle point of the parametric stabilizer and its positive terminal, and the second between the output and the second input of the DC voltage comparison unit, while the middle point of the first resistive divider is connected to the second input of the unit DC Comparisons, and the mean point

второго резистивного делител - с охранным кольцом.the second resistive divider - with a guard ring.

Claims

The drawing shows a schematic diagram of the detector. The level indicator contains a mains transformer 1, a bridge rectifier 2, the first and second parametric stabilizers 3 and 4, the guard ring 5 of the level sensor, electrode 6, the vessel of the process vessel 7, block 8 for comparison of direct voltage with inputs 9 and 10 (comparator) , resistors 11 and 12, amplifier 13 with a delay for actuation, equivalent resistance of interelectrode leaks 14, 15 and 16, resistors 17, 18, 19 and 20. The signaling device works as follows. , In the initial period of operation of the device, the dust settling on the sensor insulators is small. Under these conditions, the guard ring 5 is still quite effective, and only two leaks have a significant effect on the sensitivity of the level detector: between the sensor electrode and the guard ring and between the guard ring and the vessel body. Stabilizing the sensitivity of the detector when these leaks change over a wide range is carried out by a parametric stabilizer and a resistive divider formed by resistors 11 and 12. During further operation of the level detector, the layer of conductive dust on the sensor's insulators increases, the effectiveness of the guard ring decreases sharply. A leak 16 between the electrode 6 and the casing of the process vessel 7 appears. As the leakage resistance 16 at the input 9 of the voltage comparison unit decreases, the signal increases, which leads to an increase in the sensitivity of the device. Simultaneously with this process, due to a decrease in the resistance of leakages 16, 14 and 15 in the circuit: the middle point of the first para metric stabilizer 3 resistors G7, 19 and 21 is the total leakage resistance 16, 15 and 14 of the vessel of the process-7 minus clamp the parametric stabilizer 4 increases the current, which leads to an increase in the voltage drop across the resistor 17, and, consequently, causes an increase in the reference voltage at the input 10 of the voltage comparison unit 8, which reduces the sensitivity of the voltage comparison unit, i.e. and a threshold for triggering a detector. At the same time, the effect on the sensitivity of the voltage comparison unit flowing through the resistors 19 and 20 from the output of the unit 8 to the input 10 decreases. At the same time, the lower the leakage resistance, the less the influence of this current on the sensitivity of the voltage comparison unit which increases the return rate of the voltage comparison unit, i.e., leads to stabilization of the release of the detector. Thus, in the proposed level detector, the sensitivity is stabilized under conditions of high humidity and dustiness while monitoring the level of high-resistance media during the whole operation time, which allows to increase the reliability of the level detector and reduce operating costs. The invention of the level indicator on the author. St. No. 51690.7 characterized by the fact that, in order to increase the reliability in controlling the level of materials with low electrical conductivity, it should be additionally inserted into 7 cores of which is installed between the midpoint of the first parametric stabilizer and its positive terminal, and the second between the output and the second input DC Voltage Comparison Unit. the middle point of the first resistive divider is connected to the second input of the DC voltage comparison unit, and the middle point of the second resistive divider is connected to the guard ring. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 516907, cl. Q 01 F 23/24, 1976.