SU521502A1

SU521502A1 - Device for continuous measurement of the concentration of the dispersed phase aerosol

Info

Publication number: SU521502A1
Application number: SU2044219A
Authority: SU
Inventors: Владимир Иванович Евдокимов; Борис Иванович Попов; Валентин Васильевич Румянцев; Владислав Ильич Турубаров
Original assignee: Ленинградский Институт Авиационного Приборостроения
Priority date: 1974-07-16
Filing date: 1974-07-16
Publication date: 1976-07-15

Description

УСТРОЙСТВО дл НЕПРЕРЫВНОГО ИЗМЕРЕНИЯ DEVICE FOR CONTINUOUS MEASUREMENT

(54) КОНЦЕНТРАЦИИ ДИСПЕРСНОЙ ФАЗЫ АЭРОЗОЛЯ(54) CONCENTRATION OF THE DISPERSED PHASE OF AEROSOL

Изобретение относитс к устройствам дл измерени концентрации дисперсной фазы аэрозол и может быть использовано в различных отрасл х промышленности и медицины.The invention relates to devices for measuring the concentration of the dispersed phase of an aerosol and can be used in various fields of industry and medicine.

Известны устройства дл непрерывного измерени запыленности газов 1. Однако эти устройства обладают низкой чувствительностью и непригодны при малых концентраци х дисперсной фазы.Devices are known for continuously measuring the dust content of gases 1. However, these devices have low sensitivity and are unsuitable at low concentrations of the dispersed phase.

Наиболее близким к предложенному вл етс устройство, содержащее корпус, зар дную камеру коронного разр да с заземленными игольчатыми электродами, измерительный электрод, электрически соединенный со входом усилител , экраны, установленные с обеих сторон измерительного электрода вдоль направлени движени аэрозол 2. Недостатком известного устройства вл етс низка помехоустойчивость устройства, а в р де случаев и недостаточно высока чувствительность.The closest to the proposed is a device comprising a housing, a corona discharge charging chamber with grounded needle electrodes, a measuring electrode electrically connected to the amplifier input, screens mounted on both sides of the measuring electrode along the direction of movement of the aerosol 2. A disadvantage of the known device is the noise immunity of the device is low, and in a number of cases the sensitivity is not high enough.

Дл повышени помехоустойчивости и уменьшени габаритов в предлагаемом устройстве экраны вьшолнены в виде наборов коаксиально расположенных тонкостенных цилиндров, электрически св занных между собой, зар дна камера снабжена решеткой из электропроводного материала, причем заземленные игольчатые электроды расположены To increase the noise immunity and reduce the dimensions in the proposed device, the screens are made in the form of sets of coaxially arranged thin-walled cylinders electrically connected to each other, the charge chamber is provided with a grid of electrically conductive material, and the grounded needle electrodes are located

против центров каждой из чеек упом нутой решетки , а измерительный электрод выполнен в виде набора коаксиально расположенных тонкостенных цилиндров с шагом набора, равным соответствуюшему шагу набора в экранах. Указанные изменени позвол ют повысить чувствительность устройства без увеличени габаритов устройства.against the centers of each of the cells of the lattice, and the measuring electrode is made as a set of coaxially arranged thin-walled cylinders with a set pitch equal to the corresponding set pitch in the screens. These changes increase the sensitivity of the device without increasing the size of the device.

На чертеже изображен продольный разрез устройства со следующими элементами: 1 - металлическа труба; 2 -потенциальный электрод зар дной камеры; 3 - цилиндрическое кольцо, с закрепленными в нем заземленными игольчатыми электродами; 4 - первый трубчатый экран; 5 - измерительный электрод камеры; 6 - второй трубчатый экран; 7 - изoл цJиoнныe кольца; 8 -воздуходувка; 9высокозольтныйисточник напр жени ; 10 -усилитель; 11- указатель концентрации пыли.The drawing shows a longitudinal section of the device with the following elements: 1 - metal pipe; 2 — potential electrode of the charge chamber; 3 - a cylindrical ring with grounded needle electrodes attached to it; 4 - the first tubular screen; 5 - measuring electrode of the chamber; 6 - the second tubular screen; 7 - insulating rings; 8 blower; 9 high voltage voltage source; 10-amplifier; 11- dust concentration indicator.

Claims

In tube 1, in series in the direction of air flow, a charge chamber 2 is installed with an electrically conductive grid made, for example, with honeycomb cells, in the center of each of which are grounded needle electrodes 3, the first tubular screen 4, the measuring electrode 5 consisting of coaxial a set of thin-walled cylinders electrically connected to each other, a second tubular screen 6 and a blower 8. The device operates as follows. High voltage (thous) voltages are applied to the electrodes 2 and 3 of the charging chamber. By passing the test air flow through the measuring unit, the line of dust particles contained in it is charged in the corona pulse discharge field between electrodes 2 and 3 and, falling inside the measuring electrode 5, induces an electric charge on it proportional to the concentration of dust in the air . This charge is recorded using an electronic circuit and is fed to a dust concentration indicator in the air. The tubular screens 4 and 6 eliminate the effect of noise on the measuring electrode that occurs during a corona discharge in the charging chamber and when the blower operates. The main source of interference induced on the measuring electrodes is a powerful electric field arising in the discharge gap of the charging chamber when high-voltage pulses are applied to it. The frequency of these pulses coincides with the frequency of the succession of packets of charged particles through the measuring chamber, therefore protection against this interference by reducing the passband of the measuring amplifier is impossible. The quality of the shielding of the measuring electrode is determined by the following basic design parameters of the screens: the length of the screens; the number of shielding cylinders; the distance of the measuring chamber with screens from the source of interference L; the ratio of screen lengths to the cylinder set pitch. Experimental studies have shown that when screening in accordance with the claims of the invention, the screen length and its relation to the cylinder set should be as large as possible, since this improves the conditions for closing the power lines and reduces the field on the surface of the screens; the probability of interference in the area of the measuring electrode. Increasing the distance of the measuring chamber from the source of interference (charging chamber) also reduces the amount of induced interference. With an increase in the number of coaxial cylinders, the surface of the screen also increases, and, consequently, the probability of closing the lines of force on the screen, and not on the measuring electrodes. If the number of screens is equal to the number of coaxial cylinders in the measuring chamber, the conditions of closing of the power lines are optimal, and the highest noise immunity of the device is achieved. Claim 1. Device for continuous measurement of the concentration of the dispersed phase aerosol, comprising a housing, a corona discharge chamber with grounded needle electrodes, a measuring electrode electrically connected to the amplifier input, screens mounted on both sides of the measuring electrode along the direction of movement of the aerosol, characterized by the fact that, in order to improve noise immunity, the screens are made in the form of sets of coaxially arranged thin-walled cylinders, electrically connected between a. 2. The device according to claim 1, characterized in that, in order to reduce its dimensions, the charge chamber is provided with a grid of electrically conductive material, the grounded needle electrodes are located opposite the centers of each of the cells of said grid. 3. The device according to claim 2, characterized in that the measuring electrode is made as a set of coaxially arranged thin-walled cylinders with a set step equal to the corresponding set step in the screens. Sources of information taken into account in the examination: 1. Izmailov G. A. A device for the continuous measurement of dusty gases. Instrument making, № 3,1959.

2. Author's certificate No. 113558, MKI G 01 N, 15/02, BI No. 6.1958 (prototype).