SU932288A1

SU932288A1 - Device for thermometer graduation and checking

Info

Publication number: SU932288A1
Application number: SU802957366A
Authority: SU
Inventors: Алексей Михайлович Костецкий; Анатолий Иванович Киц; Николай Алексеевич Романюк; Василий Богданович Дунец
Original assignee: Львовский Ордена Ленина Государственный Университет Им.И.Франко; Предприятие П/Я А-7843
Priority date: 1980-07-16
Filing date: 1980-07-16
Publication date: 1982-05-30

Description

Изобретение относится к области тепловых и температурных измерений, а именно к испытанию и калибровке термометров.The invention relates to the field of thermal and temperature measurements, namely the testing and calibration of thermometers.

Известны устройства для градуировки и поверки термометров, состоящие из набора металлов, тиглей для рас плава этих металлов, средств графитовой защиты нагретого металла от окисления, Поверочной камеры. Принцип действия таких устройств состоит в сли чении показаний образцового термомет ра с точками затвердевания известных металлов [1].Known devices for calibrating and calibrating thermometers, consisting of a set of metals, crucibles for the melt of these metals, means of graphite protection of a heated metal from oxidation, and a calibration chamber. The principle of operation of such devices is to compare the readings of a reference thermometer with the solidification points of known metals [1].

Недостатком этих устройств является низкая точность определения ре перных точек за счет окисления металлов и нарушения допустимой степени их чистоты, а также зависимость положения температурных точек затвердевания расплавов от внешних условий: влажности, температуры, давления.The disadvantage of these devices is the low accuracy of determining the reference points due to the oxidation of metals and violation of the permissible degree of their purity, as well as the dependence of the position of the temperature points of solidification of the melts on external conditions: humidity, temperature, pressure.

Наиболее близким к предлагаемому является устройство, содержащее ис точник белого света и последовательно размещенные по оптической оси анализатор, термочувствительный элемент, поляризатор и регистрирующий блок [2]Closest to the proposed is a device containing a white light source and sequentially placed along the optical axis of the analyzer, a thermosensitive element, a polarizer and a recording unit [2]

Недостатками устройства является низкая точность градуировки и поверки термометров, вызванная несовершенством самого устройства.The disadvantages of the device is the low accuracy of calibration and verification of thermometers caused by imperfection of the device itself.

Цель изобретения - повышение точности градуировки и поверки термометров за счет увеличения числа реперных точек.The purpose of the invention is to increase the accuracy of calibration and verification of thermometers by increasing the number of reference points.

Указанная цель достигается тем, что в устройство введены светоделительная пластинка, размещенная между поляризатором и термочувствительным элементом, выполненным из оптически прозрачного кристалла с полиморфизмом и размещенным в камере с нагревательным элементом и регулирующий блок, выход которого связан с нагревательным элементом, а вход - с выходом фотоприемника регистрирующего блока.This goal is achieved by the fact that a beam splitting plate is inserted into the device, placed between the polarizer and the thermosensitive element made of an optically transparent crystal with polymorphism and placed in the chamber with the heating element and a control unit, the output of which is connected to the heating element, and the input - with the output of the photodetector registration unit.

б устройство дополнительно введены фотоприемник, оптически связанный с светоделительной пластинкой, выход которого подключен к входу дополнительного регистрирующего блока. 5b the device is additionally introduced a photodetector optically coupled to a beam splitter plate, the output of which is connected to the input of an additional recording unit. 5

На фиг. 1 приведена схема выполнения устройства для поверки и градуировки термометров; на фиг. 2 - зависимость относительной интенсивности прошедшего света через кристалл от to его температуры, включая при этом и точку структурного перехода кристалла.In FIG. 1 shows a diagram of a device for checking and graduating thermometers; in FIG. 2 - dependence of the relative intensity of transmitted light through the crystal on to its temperature, including the point of structural transition of the crystal.

У сгройство включает в себя источник 1 белого света, поляризатор 2, поверочную камеру 3, кристалл 4, свето- »5 делительную пластинку.5, анализаторThe unit includes a white light source 1, a polarizer 2, a calibration chamber 3, a crystal 4, a light ”5 dividing plate. 5, an analyzer

6, фотоприемники 7 и 8, регистрирующие блоки 9 и 10, нагревательный элемент 11, регулирующее устройство 12.6, photodetectors 7 and 8, recording blocks 9 and 10, a heating element 11, a regulating device 12.

Устройство работает следующим об- 20 разом.The device operates as follows 20 times.

Параллельный луч белого света от источника 1 проходит через оптическую систему лоляриэатор-кристалл-ана- 2$ лизатор и попадает на фотоприемник 7, ток которого регистрируется регистрирующим блоком 9. Перед поляризатором 6 установлена светоделительная пластинка, отделяющая от основного луча эд луч, предназначенный для качественного контроля освещенности кристалла в момент структурного перехода,сопровождающегося уменьшением интенсивности ос новного луча.Момент структурного пере- 3 хода регистрируют регистрирующим блоком 9 но уменьшению тока до минимума.Одновременно от фотоприемника 7 ток поступает на вход регулятора 12 температуры . .поверочной камеры 3.Саморегулирование температуры в поверочной камере 3 производится по известной схеме Да, Нет. Как видно из фиг. 2, при температуре кристалла, превышающей точку структурного перехода, интенсивность _<5прошедшего светового потока близка к нулю, следовательно ток фотоприемникаA parallel beam of white light from source 1 passes through the optical system of the polarizer-crystal-analyzer 2 $ analyzer and enters the photodetector 7, the current of which is detected by the recording unit 9. In front of the polarizer 6 there is a beam splitter separating the ed beam from the main beam, intended for high-quality monitoring the illumination of the crystal at the time of the structural transition, accompanied by a decrease in the intensity of the main beam. The moment of the structural transition 3 is recorded by the recording unit 9 but with a decrease in t eye to a minimum. Simultaneously, from the photodetector 7, the current is supplied to the input of the temperature controller 12. of the calibration chamber 3. Self-regulation of temperature in the calibration chamber 3 is carried out according to the well-known scheme Yes, No. As can be seen from FIG. 2, when the crystal temperature exceeds the structural transition point, the intensity _{<5 of the} transmitted light flux is close to zero, therefore, the photodetector current

7, управляющего регулятором 12 температуры, также равен нулю. Отсутствие управляющего входного напряжения на регуляторе температуры, соответствует ’ команде Нет, согласно которой ток в нагревателе поверочной камеры уменьшается и камера охлаждается. При температуре, несколько меньшей точки структурного перехода, интенсивность ⁵⁵света максимальная, максимальный ток и соответственно, на вход регулятора поступает напряжение отличное от нуля.7 controlling the temperature controller 12 is also zero. The absence of a control input voltage on the temperature controller corresponds to the No command, according to which the current in the heater of the calibration chamber decreases and the chamber cools. At a temperature slightly lower than the point of the structural transition, the light intensity ⁵⁵ is maximum, the maximum current and, accordingly, a voltage other than zero is applied to the input of the controller.

срабатывает схема Да, согласно которой ток в нагревателе камеры возрастает и происходит нагревание.Yes circuit is triggered, according to which the current in the chamber heater increases and heating occurs.

Выбор термочувствительного элемента в виде прозрачного оптического кристалла, обладающего полиморфизмом, основан на том, что при фазовых переходах таких кристаллов резко измеряются их оптические свойства, которые в частности обусловлены изменением оптической индикатрисы .и рассеяния света при переходах между низкосимметричной и высокосимметричными фазами.The choice of a thermosensitive element in the form of a transparent optical crystal with polymorphism is based on the fact that their optical properties are sharply measured during phase transitions of such crystals, which are, in particular, due to a change in the optical indicatrix and light scattering during transitions between low-symmetric and highly symmetric phases.

Например, тригональной·сингонии соответствует оптическая индикатриса в виде эллипсоида вращения, кубической - в виде шара; Поэтому, при переходе из тригональной сингонии в кубическую, наблюдается резкое изменение (уменьшение) интенсивности прошедшего светового потока. Такое изменение интенсивности обусловлено как рассеянием света в -^очке перехода, так и тем, что кристалл тригональной сингонии помещенный между скрещенными поляризаторами вносит дополнительную разность хода, а для кристалла кубической сингонии она равна нулю. Соответственно, в первом случае интенсивность светового потока, прошедшего через систему поляризатор-кристалланализатор, отличается от Нуля, а при разности хода равной нулю интенсивность светового потока также равна нулю. ПоДобное изменение интенсивности наблюдается при переводе между Другими низкосимметричной и высокосимметричной фазами при условии соответствующей исходной ориентации кристаллической пластинки относительно луча света.For example, trigonal · syngony corresponds to an optical indicatrix in the form of an ellipsoid of revolution, cubic - in the form of a ball; Therefore, when switching from trigonal to cubic, there is a sharp change (decrease) in the intensity of the transmitted light flux. Such a change in intensity is due to both the scattering of light at the transition point and the fact that a trigonal crystal placed between crossed polarizers introduces an additional path difference, and it is equal to zero for a cubic crystal. Accordingly, in the first case, the intensity of the light flux passing through the polarizer-crystallizer system differs from Zero, and when the path difference is zero, the light flux intensity is also zero. A similar change in intensity is observed during the transition between the other low-symmetric and high-symmetric phases, provided that the initial orientation of the crystal plate relative to the light beam is corresponding.

В качестве термочувствительного элемента могут быть использованы кристаллы титаната висмута, молибдата гадолиния, титаната бария, кремнезема и ряд других кристаллов.Crystals of bismuth titanate, gadolinium molybdate, barium titanate, silica, and a number of other crystals can be used as a heat-sensitive element.

Использование, например, титаната бария дает возможность получать реперные точки в области низких температур.The use, for example, of barium titanate makes it possible to obtain reference points at low temperatures.

Наличие в устройстве оптических средств измерения структурной точки перехода кристалла дает возможность осуществить дистанционное определение реперных точек, а также дает возможность применить саморегулирование температуры, суть которого состоит в том, что используемый кристалл одновременно является датчиком, управляющим поддержанием температуры своего же фазового перехода. В результате саморегулирования достигается высокая точность поддержания температуры фазового перехода, т. е. реперной точки в течение длительного промежутка времени, необходимого для градуировки термопар, что практически*⁰невозможно достичь применяя внешний регулятор.The presence in the device of optical means of measuring the structural transition point of the crystal makes it possible to remotely determine the reference points, and also makes it possible to apply temperature self-regulation, the essence of which is that the crystal used is simultaneously a sensor that controls the maintenance of the temperature of its own phase transition. As a result of self-regulation, high accuracy is maintained in maintaining the temperature of the phase transition, i.e., the reference point for a long period of time necessary for the calibration of thermocouples, which is practically * ⁰ impossible to achieve using an external regulator.

Предлагаемое устройство,, в отличие от известного, может применяться в более широкой области температур, поскольку кристаллы могут использоваться для поверки и в области отрицательных TeMnepatypiThe proposed device, unlike the known one, can be used in a wider temperature range, since crystals can be used for verification in the negative TeMnepatypi region

Claims

The invention relates to the field of thermal and temperature measurements, namely to the testing and calibration of thermometers. Devices for calibration and verification of thermometers, consisting of a set of metals, crucibles for melting these metals, means of graphite protection of the heated metal from oxidation, and a verification chamber are known. The principle of operation of such devices consists in comparing the indications of an exemplary thermometer with solidification points of known metals. The disadvantage of these devices is the low accuracy of determining reference points due to the oxidation of metals and the violation of permissible degree of their purity, as well as the dependence of the temperature of solidification points of the melts on the external condition: humidity , temperature, pressure. The closest to the proposed device is a device containing a white light spot and successively placed along the optical axis an analyzer, a temperature-sensitive element, a polarizer and a recording unit 2. The drawback of the device is the low accuracy of calibration and calibration of thermometers caused by the imperfection of the device itself. The purpose of the invention is to improve the accuracy of calibration and calibration of thermometers by increasing the number of reference points. This goal is achieved by inserting a beam-splitting plate in the device, placed between the polarizer and a temperature-sensitive element made of an optically transparent crystal with polymorphism and placed in a chamber with a heating element and a regulating unit, the output of which is connected to the heating element, and the input is the output of the photodetector of the registered unit. A photodetector optically coupled to the separator plate, the output of which is connected to the input of the additional recording unit, is additionally introduced into the device. Fig. "1 is a schematic of the device for checking and calibrating thermometers; in fig. 2 shows the dependence of the relative intensity of the transmitted light through the crystal on its temperature, including the structural transition point of the crystal. The device includes a white light source 1, a polarizer 2, a vertical camera 3, a crystal, a beam-splitting plate.5, an analyzer 6, photodetectors 7 and 8, the registering units 9 and 10, the heating element 11, the regulating device 12. The device p1 returns as follows. A parallel white light beam from source 1 passes through the optical system of the full pvfeato {-crystal analyzer and hits a photodot 1 "7 7 which current is recorded by the recording unit 9. A beam splitter is installed in front of the helivator 6, which separates the beam from the main beam to achieve quality control The ocB teHHOCTH of the crystal at the time of the structural transition, accompanied by a decrease in the intensity of the main beam. The moment of the structural transition is recorded by the registering unit 9 by reducing the current to a minimum .At the same time from the photodetector 7, the current is supplied to the input of the temperature controller 12. Of the verification chamber 3. The temperature in the verification chamber 3 is self-controlled according to the known c) Yes, No. As can be seen from the fig. 2, when the temperature of a crystal pinging a structural transition point, the intensity of the transmitted light flux is close to zero, hence the current of the photodetector 7 controlling the temperature regulator 12 is also zero. The absence of a control input voltage at the temperature controller corresponds to the No command, according to which the current in the heater of the test chamber decreases and the camera cools. At a temperature slightly lower than the structural transition point, the light intensity is maximum, the maximum current and, accordingly, a voltage other than zero is applied to the regulator input. The circuit operates Yes, according to which the current in the chamber heater increases and heating occurs. The choice of a thermosensitive element in the form of a transparent-optical crystal with polymorphism is based on the fact that during phase transitions of such crystals their optical properties are sharply measured, which in particular are due to a change in the optical indicatrix and scattered light at transitions between low-symmetry and high-symmetry phases. For example, trigonal singsing corresponds to the optical indicatrix in the form of an ellipsoid of rotation, cubic - in the form of a ball; Therefore, upon transition from a trigonal system to a cubic one, a sharp change (decrease) in the intensity of the transmitted light flux is observed. Such a change in the intensity is caused both by the scattering of light in the transition and by the fact that the crystal of the trigonal syngony placed between the crossed polarizers introduces an additional path difference, and for the crystal of the cubic syngony it is zero. Accordingly, in the first case, the intensity of the luminous flux transmitted through the polarizer-crystallizer system is different from yule, and when the path difference is equal to zero, the intensity of the luminous flux is also zero. Similar to the intensity change is observed when converting between Other yymosymmetric and high-symmetry phases under the condition% the initial orientation of the crystal plate relative to the light beam. Crystals of bismuth titanate, gadolinium molybdate, barium titanate, silica, and a number of other crystals can be used as a thermosensitive element. Using, for example, barium titanate makes it possible to obtain reference points in the region of low temperatures. The presence in the device of optical means for measuring the structural transition point of a crystal makes it possible to carry out remote determination of reference points, and also makes it possible to apply temperature self-regulation, the essence of which is 8 TOM, THAT the crystal used is simultaneously a sensor controlling the temperature maintenance of its own phase transition. As a result of self-regulation, a high accuracy of maintaining the phase transition temperature is achieved, i.e., the reference point for a long period of time required for the calibration of thermocouples, which is practically impossible to achieve using an external regulator. The proposed device, in contrast to the known, can be used in a wider temperature range, since the crystals can be isolated for calibration and in the area of negative TeMnepatypi. Invention V. Device for calibration and calibration of thermometers containing a white light source and sequentially placed along the optical axis an analyzer, a temperature-sensitive element, a polarizer and a register of disturbances; a unit of tl and chach it so that, c, the aim is to increase the accuracy of calibration and calibration of thermometers by increasing the number of turnips A dividing plate is inserted into it, placed between the polarizer and a thermosensitive element made of an optically transparent crystal with polymorphism and placed in a chamber with a heating element and a regulating unit whose output is connected to the heating element, and the input is connected to the output of the photodetector recording block. 2. Device pop. 1, characterized in that an additional photodetector is optically coupled to the beam-splitting plate, the output of which is connected to the input of an additional registrating unit. Sources of information taken into account in the examination of t. Lineveg F. Temperature Measurement in Engineering. Directory. M., Metallurgi, T580, p. 206.

2. USSR author's certificate “807079, cl. G 01 K P / 12, 1979 (prototype).

rel. units