SU997044A1

SU997044A1 - Pneumatic differential temperature-to-pressure converter

Info

Publication number: SU997044A1
Application number: SU813305149A
Authority: SU
Inventors: Роман Ярославович Дубиль; Александр Леонидович Колойденко; Александр Ильич Бирман
Original assignee: Предприятие П/Я В-8296
Priority date: 1981-06-25
Filing date: 1981-06-25
Publication date: 1983-02-15

Description

Изобретение относитс к пневматическим датчикам температуры и может быть использовано в системах автоматического контрол и регулировани температуры.This invention relates to pneumatic temperature sensors and can be used in automatic temperature control and regulation systems.

Известен пневматический датчик температуры дилатометрического типа, состо щий из биметаллического чувствительного элемента, вл ющегос заслонкой п евмопреобразовател соплозаслонка Cl .A pneumatic dilatometric-type temperature sensor is known, consisting of a bimetallic sensing element, which is a gate valve of a transducer with a nozzle valve Cl.

Недостатком такого датчика вл етс ограниченна точность, обуслов- i ленна низкой чувствительностью биметаллического элемента.:The disadvantage of this sensor is the limited accuracy due to the low sensitivity of the bimetallic element .:

Наиболее близким по технической сущности к изобретению вл етс пневматический датчик температуры, принцип действи которого основан на различии температурных зависимостей у турбулентного и ламинарного дросселей . дтот датчик выполнен по -мостовой схеме и состоит из регул тора входного давлени t подключенными к нему сравнительными и измерительными звень ми , выходного узла и линии сброса.The closest in technical essence to the invention is a pneumatic temperature sensor, the principle of action of which is based on the difference in temperature dependences of turbulent and laminar chokes. This sensor is made according to the bridging scheme and consists of an input pressure regulator t with comparative and measuring links connected to it, an output node and a discharge line.

Сравнительное звено состоит из двух турбулентных дросселей, а измерительное - из турбулентного и ламинарного дросселей 2.The comparative link consists of two turbulent chokes, and the measuring link consists of turbulent and laminar chokes 2.

Недостатком датчика вл етс ог раниченна точность вследствие низкой чувствительности дроссельных делителей . The disadvantage of the sensor is limited accuracy due to the low sensitivity of the choke dividers.

Целью изобретени вл етс повышение точности. The aim of the invention is to improve the accuracy.

Поставленна цель достигаетс тем, что в пневматическом дифференциальном преобразователе температу The goal is achieved by the fact that in a pneumatic differential temperature converter

10 Е л в давление, содержащем сравнительное и измерительное звень , каждое из которых состоит из последовательно соединенных входнотчэ и измерительного 5 occeлeй, регул тор дайлени , вход 10 E l in pressure, containing a comparative and measuring unit, each of which consists of a series-connected input unit and measuring unit 5, a dispatch controller, an input

15 которого соединен с каналом заданного давлени , а выход - с входными дроссел ми сравнительного и Измерительного звеньев, выходной узел, линию 2Q сброса, а также задатчик, подстроечный и квазилинейный дроссели, выходной узел выполнен в виде элемен-еа сравнени , плюсова камера которого св зана с выходом входного дроссел сравнительного звена, с другим входом 15 of which is connected to the channel of the specified pressure, and the output is connected to the inlet throttles of the comparative and measuring units, the output node, the reset line 2Q, as well as the setpoint adjuster, trimmer and quasilinear chokes, the output node is designed as a reference element, the plus chamber of which Zana with the output of the input throttle comparative link, with a different input

25 регул тора давлени , а через измерительный дроссель сравнительного звена - с линией сброса, минусова камера элемента сравнени св зана через измерительный дроссель измерительного 25 of the pressure regulator, and through the measuring throttle of the comparative link with the discharge line, the minus chamber of the comparison element is connected through the measuring throttle of the measuring

Claims

30 links with the atmosphere, through a quasilinear choke - with the output of a given element of comparison, and through a trim choke with an output of the setting device. The drawing shows a schematic diagram of the converter. The converter consists of pressure regulator 1, comparative 2 and measuring 3 links, each of which contains an input turbulent choke 4 and a measuring choke 5, as well as an input turbulent droplet 6 and measuring choke 7, respectively, the comparison element of a quasi-linear 9, trimmer 10 chokes and setting device 11. Output PX) of controller 1 through comparative 2 and measuring 3 links are connected with positive P and negative P cameras of element 8, output P of which is the output of the converter Positive camera of element 8 st It linked also to the other input of minus regularity torus l 1 directly and via the choke 5 with a reset line. The minus chamber of element 8 is connected via throttle 7, 9 and 10, respectively, to the reset line, the transformer c / output and the setpoint 11 output. The first positive input of the regulator 1 under the keys to the channel of the specified pressure P Chokes 4 and 6, 5 and 7 are selected the same, therefore, the costs through comparative 2 and measuring 3 units are equal to P to the same temperature in both units x. A change in the temperature of the experimental drop 7 by the LT value leads to a change in the flow rate through it by the value AQ. This leads to a certain change in pressure P and, consequently, to a change in pressure at the outlet of element 8. The process of changing pressure P will take place until the air flow through the throttle 9. compensates for the indicated change in flow, i.e. until the balance comes. If the flow characteristic of the throttle 9 to choose so as to compensate for the nonlinear flow through the measuring throttle 7 from the temperature, then we obtain a linear scale of the converter. This is usually easily achieved by using a laminar or quasilinear choke, since the dependence of the flow rate through the turbulent-laminar divider on temperature in a narrow measuring range of the latter has a weakly pronounced dependence. The required conversion factor is adjusted according to the ratio of the resistances of the chokes 4-6, 5-7 and 9. Due to the high sensitivity of the regulator 8, which ensures the equality of pressures with high accuracy, and with an appropriate selection of the ratio of the mentioned resistance, it is possible to obtain a sufficiently high conversion sensitivity (about 0.1 kgf / CMVc) and, consequently, highly accurate temperature measurement. For setting the beginning of the scale, the drousel 10 and the setting device 11 are used, with the help of which additional air flow is formed in the measuring unit 3. This flow simulates heating of the throttles 7 to the temperature corresponding to the origin of reference. As shown by the results of preliminary tests, the proposed converter compared to the prototype , provides a significant increase in accuracy (the error does not exceed ± 2.5% of the range of -measurement (, the time constant is within 3 s). Invention formula Pneumatic differential A temperature to pressure transducer containing a comparative and measuring unit, each of which consists of serially connected inlet and measuring throttles, a pressure regulator whose inlet is connected to a channel of a given pressure, and the output is connected to the input throttles of a comparative and measuring unit, an output node , the reset line, as well as the setting, trimming and quasilinear chokes, characterized in that, in order to improve the accuracy of the converter, the output node in it is made as an element with A positive chamber whose positive chamber is connected to the output throttle of a comparative link, with another input of a pressure regulator, and through a measuring throttle of a comparative link to a reset line, a negative hatch of the comparison element is connected through a measuring throttle from the measuring link to the atmosphere, through the quasilinear choke - with the output of this element of comparison, and through the trimmer choke - with the output of the setpoint device. Sources of information taken into account during the examination 1.Ibrahimov I.A. Elements and systems of pneumatic automation. M., High Stake, 1975, p .. 272.

2. In the same place 274 (prototype).