SU523339A1

SU523339A1 - Capacitive humidity sensor bulk materials

Info

Publication number: SU523339A1
Application number: SU1926630A
Authority: SU
Inventors: Важа Евгеньевич Пруидзе
Original assignee: Специальное Конструкторское Бюро По Проектированию Приборов И Средств Автоматизации
Priority date: 1973-06-08
Filing date: 1973-06-08
Publication date: 1976-07-30

Description

1one

Изобретение относитс к области измерительной -техники, а именно, к емкостным датчикам влажности дл сыпучих материалов и найдет применение в народном хоз йстве при измерении влажности сыпучих ма- териалоБ.The invention relates to the field of measuring equipment, namely, to capacitive humidity sensors for bulk materials and will be used in the national economy when measuring the moisture content of bulk materials.

Известны емкостные датчики влажности сыпучих мате риалов ll.Known capacitive humidity sensors bulk materials ll.

Основным их недостатком вл етс то, ..то величина их емкости, кроме влажности С1ависит от объемного веса (плотности) навески сыпучего материала, помещенного в датчике, что понижает точность измерени ,Their main drawback is that the size of their capacity, besides the humidity C 1, depends on the bulk weight (density) of the bulk solids placed in the sensor, which reduces the measurement accuracy,

b известных емкостных датчиках с плоскопараллельными электродами, выполненным в виде сосуда, образованный изолирующий основанием - двум Стенками из диэлектрика и двум плоскими электродами с пружинам и 2 б ольщое вли ние на точность измерени оказывает плотность исследуемого материала.b known capacitive sensors with plane-parallel electrodes, made in the form of a vessel, formed by an insulating base - two walls of a dielectric and two flat electrodes with springs and 2 b the density of the test material has an influence on the measurement accuracy.

Ближайшим техническим решением вл етс емкостный датчик с встречно наклонными электродами, в котором вли ние плотности исследуемого материала на результат The closest technical solution is a capacitive sensor with counter-inclined electrodes, in which the effect of the density of the material under study on the result

измерени уменьшено, но полностью не устранено , так как в этих датчиках электроды наклонены под определенным, фиксированным углом от вертикали Гз1.measurements are reduced, but not completely eliminated, since in these sensors the electrodes are tilted at a certain, fixed angle from the vertical Hz1.

При влажност х выще и ниже 13% вли ние плотности муки в датчиках с наклонными электродами уменьшаетс , но не устран етс полностью. Поэтому такие датчики целесообразно использовать дл сыпучих ма-териалов, влажность которых мен етс в небольших пределах.At higher humidities and below 13%, the effect of flour density in sensors with inclined electrodes is reduced, but not completely eliminated. Therefore, such sensors are advisable to use for bulk materials, the humidity of which varies in small limits.

Кроме того, недостатком датчиков с наклонными электродами вл етс то, что дл каждого сыпучего материала требуетс свой, определенный угол наклона, поэтому изготовленный датчик пригоден только дл одного сыпучего материала.In addition, a disadvantage of sensors with inclined electrodes is that each bulk material requires its own, certain angle of inclination, therefore, the manufactured sensor is only suitable for one bulk material.

Claims

The purpose of the inventive shadow is to improve the measurement accuracy by eliminating the effect of the change in density of the bulk material under investigation on the measurement result at any humidity values. For this, in the proposed sensor, flat electrodes are suspended by upper ends on rotating sleeves fixed in the side Walls of the sensor by springs. FIG. 1 shows a schematic of the sensor, where 1 is flat electrodes; 2 - insulating sensor base; 3 dielectric walls of the sensor, on which electrodes 1 are suspended; 4 - springs opposing the rotation of the sensor electrodes. The device works as follows. When the sensor is empty, i.e. there is no sample of the bulk material under investigation in it, and the flat electrodes of the sensor, under the action of their own weight, occupy a vertical position with respect to the insulating base. The planes of the electrodes are parallel to each other, the sensor capacitance: C 6 is the distance between where O is the distance between the electrodes. When placed in the sensor, samples of the material under study, such as flour, the electrode of the sensor experience pressure of the wet beam of the material, as a result of which they rotate around the rotating axes, therefore the distance between the electrodes is up to lb. As a result, the working capacitance of the sensor is reduced, since. The angle of rotation of the electrodes and the distance between them changes from a change in the seal in the sensor of the placed bulk material. As the seal increases, both the dielectric constant and the average distance between the electrodes increase, but the active electrode area S decreases. the permeability of the material due to an increase in the bulk density is compensated by an increase in the average distance between the electrodes and a decrease in the active area of the electrodes. S Change the distance between the electrode-. up to the desired value is achieved when calibrating the device with the help of springs that counteract the rotation of the sensor electrodes. The stiffness of the springs 4 is adjusted so that when the density of the bulk material in the sensor changes, the electrodes change their inclination from the base, i.e. the working capacity of the sensor so that a change in the capacity of the sensor due to a change in the density of the bulk material is compensated for by the working capacity of the sensor. The invention The capacitive humidity sensor for bulk materials, made in the form of a vessel formed by an insulating base, two walls of a dielectric and two flat electrodes with springs placed between their lower ends and protrusions of the base, differs in that, in order to improve measurement accuracy by eliminating influencing the density of the material under study, the electrodes are suspended by their upper ends on rotating axes fixed in the side walls of the sensor. Sources of information taken into account in the examination: 1 Berliner M, d. Measurement of humidity. M ,, 1973, s, 77.

2. Journal of Measuring Equipment 1971, No. 12 p. 67.

3. Avt.Sv. USSR, № 352206, cl. G O1W 27/22, (prototype).