Thermoelectric sensor for discrete measurement of partition level

 

(57) Abstract:

The inventive device comprises a sealed enclosure connected to prochnostnymi covers, installed in the housing at its height, ensuring end-to-end walk through it environments. Thermocouples and heaters with elektroprovodnoi installed on the exterior walls of the covers. 3 C. p. F.-ly, 4 Il.

The invention relates to measuring technique and can be used to indicate the presence or absence of fluid and discrete measurement of liquid level, including in the conditions of high temperatures, pressures and corrosive environment. Applications can be nuclear, chemical, food industry, and others that require measurement in confined and inaccessible to other observation volumes.

Known thermoelectric sensors containing thermocouples, heating elements, corresponding elektroprovodnyi and electrical insulation, enclosed in covers, tightly-tightly closed at one end and connected the other end to the housing of the sensor, the latter is installed in the tank where the level measurement (see, for example, the United Kingdom patent N 2143950, CL G 01 F 23/24, published on the s are the complexity of the design, manufacturing, large inertia action, the difficulty of ensuring bryzgogasiteli, which affects the reliability of the testimony.

Known thermoelectric sensor [1] contains sensitive elements in the covers of pipes placed in them by thermocouples and heaters, and each element has at one end an additional circular leaky case for protection against splashes, and all together the elements set out in the General case, communicated with the environment.

The disadvantages are the complexity of design and manufacture, the sluggishness of action that is difficult to improve due to the need for accommodation in a cylindrical case of small diameter thermocouple, heater, insulation, and to ensure the reliability and the requested resource must be a sufficient wall thickness of the case, especially for corrosive or life-threatening environments. Because of the small size limited the choice of structural materials. Technological difficulties are exacerbated for a considerable length of sensor (tens of meters) and the stringent requirements to the inertia action. By the greatest number of matching signs thermoelectric sensor [1] is taken as a prototype.

The purpose of accom is gnosti, reducing the inertia of the action.

The objective is achieved by the fact that the covers are installed in the housing, ensuring end-to-end walk through it environments, and thermocouples and heaters installed on the exterior walls of the covers.

Thermoelectric sensor includes a housing, which is made in the form of a pipe, and covers are made in the form of C-shaped tubes. The building is divided into several parallel structural parts, hermetically separated from the environment and from each other, and heaters thermocouples made with the ability to disable all but one, at each level of measurement. The body of the sensor is made of several parts connected firmly-firmly in height, and each part contains at least two covers, located at its opposite ends.

In Fig. 1 there is shown a transmitter, a longitudinal section; Fig. 2 section a-a in Fig. 1; Fig. 3 cross-section B-B in Fig. 2; Fig. 4th place I in Fig. 3.

Thermopile sensor consists of a tube 1, separately welded to a common flange and separately withdrawn from the housing 2 of the vessel containing the medium whose level is to be measured. Inside the pipes in several rows in height placed covers, made in the form With-shape curved t is titsa environment, the level which you want to measure, and inside hull pipes electroconductive environment, such as atmospheric air. On the outside walls of the C-shaped tubes 3 installed thermocouples 4 and through the electrical insulation 5 heater 6, made for example in the form of a spirally wound around the tube 3 wire. To reduce heat loss and reduce the temperature inside the enclosure is installed insulation 7. All the wires from all thermocouples and heaters are out. Each pipe 1 of the case is made from sections 8, near the upper and lower ends of which are embedded tubes 3, as this facilitates the installation of the pipes and the installation of thermocouples, heaters, insulation and placement of elektroprovodnyh.

All this significantly reduces the complexity of manufacture of the proposed sensor is compared with the prototype facilitates the quality control and expands the range of structural materials that can be used for this transmitter. Much better splashproof, with no need for additional covers.

The transmitter operates as follows. When passing current through the heater 6 of the wall of the tube 3 is heated. When lifting ur is 3, stops cooling, since the heat capacity of the gas is much less than the heat capacity of the liquid. The temperature change will cause a corresponding change of thermocouple signal.

This design allows the use of different schemes of receipt of the signal, or the absolute change in temperature, or the temperature difference at the differential inclusion heated and unheated, pressurized thermocouples located at the same level in height in different buildings 1. Then when the number of pipes 1 three or more one or more tubes 3 at the same level in height are reserved, this increases the overall reliability of the sensor. Comparing the sensing element of the prototype, when thermocouple and the heater is placed inside the tube, you can see that it is more inertial than the offer, as the thickness of the material layers constituting the element of the prototype, is always greater than the wall thickness of the tube of the case, whereas in the proposed sensor is a thermocouple and heater are installed directly on the wall of the pipe that provides less lag and, accordingly, greater performance, which is important in measuring systems, ensuring safe operation. In addition, decreases potrebleniia in the manufacture, than staying inside a long, thin pipe. Therefore (due to availability) it is easier to select construction materials for manufacturing. Therefore, the proposed sensor exceeds the prototype of both performance and ease of fabrication, especially for large lengths of the transmitter, with large fluctuations in the level of the measured liquid height.

1. THERMOELECTRIC SENSOR FOR DISCRETE LEVEL MEASUREMENT SECTION of the MEDIA containing a sealed enclosure connected to prochnostnymi covers, mounted on the casing, thermocouples and heaters with elektroprovodnoi, characterized in that the covers are installed in the housing, ensuring end-to-end walk through it environments, and thermocouples and heaters installed on the exterior walls of the covers.

2. The sensor under item 1, characterized in that the casing is made in the form of a pipe, and covers in the form of C-shaped tubes.

3. The sensor under item 1, characterized in that the housing is divided into several parallel prochnostnyh parts, hermetically separated from the environment and from one another, and heaters thermocouples made with the ability to disable all but one, at each level of measurement.

4. The sensor on p. 3, otlichalis the part contains at least two covers, located on its opposite ends.

 

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