SU684423A1

SU684423A1 - Capacitance-type transducer

Info

Publication number: SU684423A1
Application number: SU772559616A
Authority: SU
Inventors: Станислав Сергеевич Колотуша
Original assignee: Всесоюзный научно-исследовательский институт аналитического приборостроения
Priority date: 1977-12-26
Filing date: 1977-12-26
Publication date: 1979-09-05

Description

(54) ЕМКОСТНЫЙ ПРЕОБРАЗОВАТЕЛЬ(54) CAPACITIVE CONVERTER

Изобретение относитс к измэрительной технике и может быть использовано в металлургической, энергетической , пищевой, химической и строительной прО -1ыи1лзнностй дл измерени концентрации, скорости и расхода диэлектрических материалов, транспортируемых по трубопроводам.The invention relates to measuring technology and can be used in metallurgical, energy, food, chemical and construction applications for measuring the concentration, velocity and consumption of dielectric materials transported through pipelines.

Известны емкостные преобразозаТ1гли , содержащие элэктроды, закрепленные на поверхности диэJ.eктpичecкой трубы дл контрол параметров измельченных диэлектрических материалов , транспортируемых воздухом 1Capacitive transforms of Т1gli are known, containing elec- trodes fixed on the surface of a dielectric tube to control the parameters of comminuted dielectric materials transported by air 1

Известные преобразователи недостаточно точны при И1мэрени х.Known transducers are not accurate enough for i1mareni.

Ближайшим техническим решением к изобретению служит емкостный преобразователь, содержащий кольцевые электроды, закрепленные на поверхности диэлектрической трубы, заключенные в металлический экран 2 .The closest technical solution to the invention is a capacitive transducer containing ring electrodes mounted on the surface of a dielectric tube, enclosed in a metal screen 2.

Недостатком известного преобразовател вл етс низка точность измерени , обусловленна тем, что изменение температуры окружающей среды приводит к изменению размеров и диэлектрической проницаемости трубопровода, на котором закреплены кольцевые электроды. В результате измен етс рассто ние между кольцевыми электрэдами, а следовательно , и начальна емкость преобразовател .A disadvantage of the known converter is the low measurement accuracy due to the fact that a change in the ambient temperature leads to a change in the size and dielectric constant of the pipeline on which the ring electrodes are fixed. As a result, the distance between the ring elec- trodes and, consequently, the initial capacitance of the converter, changes.

Изменение рассто ни межд-. кольцевыми электрэдами имеет значительную величину, так как коэффициенты The change in distance between -. ring electrolights have a significant value, since the coefficients

0 линейного расширени фторопластовс го трубопровода и металлов, примен емых дл изготовлени электродод, , соответственно равны (Вт25) 10 К и (12f25) 10 к , т.е. различают5 с на пор док.0 linear expansion of the fluoroplastic pipeline and the metals used to manufacture the electrode,,, are respectively (W25) 10 K and (12f25) 10 K, i.e. distinguish between 5 seconds of order.

Учитыва , что изменение температурного коэффициента диэпектрической прОЧицаемости равно (2тЗ)- 10 К . Taking into account that the change in the temperature coefficient of the dielectric stability is equal to (2 t3) - 10 K.

0 изменением диэлектрической проницаемости фторопласта можно пренебречь.0 the change in the dielectric constant of the fluoroplastic can be neglected.

Цель изобретени - повьппение точности измерени при высоких температурах .The purpose of the invention is to increase the measurement accuracy at high temperatures.

5five

Claims

The goal is achieved by the fact that the electrodes are made in the form of sliding telescopic rings, the ends of which are fixed in a dielectric tube. The drawing shows the proposed Converter in the section. The capacitive transducer contains two ring electrodes, each of which is made of sliding, telescopic rings 2 attached respectively to the annular ledges 3,4 of the dielectric tube 5. The sliding telescopic rings of the electrodes are coupled to each other by a sliding fit due to the annular grooves in the thickness of the electrode 1 , 2. Depending on the converter manufacturing technology, the annular protrusions 3,4 can be made as separate rings screwed along the thread on the dielectric tube 5. The electrodes of the sliding telescopic elements are enclosed in a metal screen and connected to the input of a capacitance meter (not shown). The Converter operates as follows. When voltage is applied to potential electrodes inside the dielectric tube, a longitudinal electric field is created. With increasing temperature, the flow or the environment, the dielectric tube 5 is heated, the distance between the ring electrodes increases, which reduces the initial capacitance of the converter. Since the ends of the ring electrodes are fixed between the annular heights of 3.4 of the dielectric tube 5, the rings 2 are simultaneously being pulled out of the rings 1, leading to an increase in the active surface of each electrode. 34 As the electrodes expand, their active area increases, which increases the initial capacitance of the converter. The increase in the distance between the two ring electrodes is continuously and automatically compensated for by a corresponding increase in the area of the telescopic electrodes. The inverse of this process occurs when the temperature of the stream or the environment decreases. Thus, in the course of the measurement, automatic temperature compensation of changes in the initial capacity of the preconditioner occurs continuously. The proposed device can be made on a lathe. Claims of Invention A capacitive transducer comprising annular electrodes mounted on the surface of a dielectric tube enclosed in a metal screen, characterized in that, in order to improve measurement accuracy at high temperatures, the electrodes are designed as sliding telescopes, the ends of which are fixed in a dielectric tube. Sources of information taken into account in the examination 1. USSR author's certificate number 262763, class, C 01 N 27/22, L967.

2. USSR author's certificate number 211812, cl. G 01 F 05/00, 1965.