SU881588A1

SU881588A1 - Optomolecular hygrometer

Info

Publication number: SU881588A1
Application number: SU792747426A
Authority: SU
Inventors: Николай Степанович Лидоренко; Иосиф Арнольдович Зайденман; Борис Иванович Ильин; Александр Михайлович Капустин; Сергей Петрович Козуб; Владимир Иванович Кутаков; Александр Борисович Малиновский; Владимир Леонидович Рычков; Григорий Константинович Смирнов
Original assignee: Предприятие П/Я В-2763
Priority date: 1979-04-03
Filing date: 1979-04-03
Publication date: 1981-11-15

Description

(54) ОПТОМОЛЕКУЛЯРНЬЙ ГИГРОМЕТР(54) OPTOMOLECULAR HYGROMETER

II

Изобретение относитс к влагометрии и может быть использовано дл измерени относительной влажности в качестве селективного датчика ионного и газового состава среды;The invention relates to moisture measurement and can be used to measure relative humidity as a selective sensor for ion and gas composition of a medium;

Известны гигрометры дл измерени относительной влажности, содержащие в качестве основных элементов источник света, фотоприемник и чувствительный к влажности элемент, способный измен ть окраску в зависимости от влажности среды 1 .Hygrometers for measuring relative humidity are known, containing as main elements a light source, a photodetector, and a moisture-sensitive element capable of changing color depending on the humidity of the medium 1.

Однако из-за потерь на отражение известные устройства имеют недостаточные чувствительность и быстродействие . However, due to the loss of reflection of the known devices have insufficient sensitivity and speed.

Наиболее близким техническим решением к изобретению вл етс оптомолекул рный гигрометр, содержащий датчик, состо щий из последовательно расположенных малоинерционного Источника света, влагочувствительного элемента, приемного фотоэлемен .та и электронный блок с блоком питанин источника света и регистратором 2 .The closest technical solution to the invention is an opto-molecular hygrometer containing a sensor consisting of successively located low-inertia light sources, a moisture-sensitive element, a receiving photocell, and an electronic unit with a pitan light source unit and a recorder 2.

Недостатком этого устройства вл етс инерционность, так как ввиду малой интенсивности источника света (светодиода) и потери света при диффузном отражении от влагочувствительного элемента необходим защитный экран, замедл ющий процессы обмена влагой и снижаклций быстродейст10 вие. Кроме того, используемый в качестве регистратора простой компаратор , сравнивающий сигналы основного и опорного каналов, не дает надежного вьщелени полезного сигнала на A disadvantage of this device is inertia, since, due to the low intensity of the light source (LED) and the loss of light during diffuse reflection from the moisture-sensitive element, a protective screen is needed, which slows down the exchange of moisture and decreases the speed. In addition, a simple comparator used as a recorder that compares the signals of the main and reference channels does not reliably allocate the desired signal to

ts фазе засветки.ts phase illumination.

Целью изобретени вл етс увеличение быстродействи оптомолекул рного гигрометра.The aim of the invention is to increase the speed of an optical molecular hygrometer.

Дл дости;кени указанной цели в To achieve this goal in

Claims

A well-known optical molecular hygrometer containing a sensor consisting of successively located low-inertia light source, a sensitive element, a receiving photocell, and an electronic unit with a light source power supply unit and a recorder, a moisture sensitive element made in the form of a cylinder with a cone-shaped face facing the source light, and the recorder is equipped with a synchronous detector. The drawing shows a schematic diagram of an optical molecular hygrometer. The optoelectric hygrometer circuit contains a sensor 1 and an electronic unit 2. The sensor consists of a housing 3, a low-inertia light source 4 located at the cone-shaped end of the moisture-sensitive element 5 covered with a moisture-sensitive layer 6. The receiving photocell 7 is located at the opposite end of the light. The hygrometer includes a power supply unit 8, a synchronous detector 9 and a recorder 10. A cylindrical moisture-sensitive element (light guide) 5 is made of polystyrene crosslinked with divinylbenzene, It is a thin (5–10 µm) cation-exchange layer in the C-form, obtained by synthesizing ion-exchange materials. The hygrometer works as follows. P1 pulses of light from the source 4 connected to the power supply unit of the pulse voltage 8, due to total internal reflection from the highly sensitive layer 6, fall on the receiving photocell 7. The current pulses of the receiving photocell following the frequency of the light pulses of the source 4 are recorded by a synchronous detector 9 and cause in the recorder 10 a current proportional to the amplitude of the pulses. The amplitude of the pulses of the current of the receiving photocell is determined by the amplitude of the pulses of the source 4 and the absorption of light in the moisture sensitive layer 6, which, in turn, depends on the humidity of the external medium in contact with this layer. Thus, the readings of the recorder 10 depend on the humidity of the external environment. The external illumination falling on the receiving photocell7. Is determined by a synchronous detector and does not affect the readings of the recorder 10. The realization of the moisture sensitive element 5 in the form of a cylinder with a cone-shaped end makes it possible to more efficiently use the light emitted by the source, since the formation of a beam of full internal reflection ( AIR) does not occur on a flat surface on which a large part of the light is lost, but on a conical one. Reducing the loss of light allows increasing the length of the moisture sensitive element and, while maintaining the same sensitivity, reducing the thickness of the moisture sensitive layer, since water exchange processes in the layer are diffusion, the thickness of the layer essentially determines the response speed (response time, where 1 is the thickness of the moisture sensitive layer). Reducing the thickness of the moisture-sensitive layer by 1.5 times leads to a decrease in the relaxation time of this layer by more than 2 times. The opto-molecular hygrometer is highly sensitive in the whole range of humidity from 0.1 to 100%, the measurement error is not more than 1%, the response time does not exceed 10 s. The use of the invention allows to increase the speed of hygrometers more than 6 times with high sensitivity measurements of relative humidity. Claims of the invention An opto-molecular hygrometer comprising a sensor consisting of successively arranged maine-inertial light source, moisture sensitive element, receiving photocell, and an electronic unit with a light source power supply unit and a recorder, characterized in that, in order to increase speed, the moisture sensitive element is made as a cylinder with a cone-shaped face facing the light source, and the recorder is equipped with a synchronous detector. Sources of information taken into account during the examination 1.CIUA patent No. 3557619, cl. G 01 N 21/22, published 1971.

2. USSR author's certificate number 561896, cl. G 01 N 21/10, 1977 (prototype).