RU203571U1 - High temperature thermoelectric converter - Google Patents

Abstract

The utility model relates to thermometry, namely to thermoelectric converters (TP) intended for their installation in temperature control devices in high-temperature technological processes. The utility model can be used to measure the temperature of high-temperature processes in power engineering, metallurgy, chemical, oil, gas and other industries. The technical result of the proposed solution is the development of a TP design with increased resistance to aggressive media and high temperatures, therefore, their service life increases. The thermoelectric high-temperature converter with a sensitive element made of a metal wire, placed in a protective armature made of a metal tube rolled and welded on the one hand, at the boundary of the immersed part, which is in contact with the working medium, the temperature of which must be measured, a limiting washer is welded to the protective armature for installing a thermal converter at the temperature control object, characterized in that the immersed part of the protective armature, welded seams and part the limiting washer, interacting with the working medium, is covered with an anticorrosive layer of powdered aluminum, applied by cold gas-dynamic spraying, while the thickness of the coating layer is from 20 to 50 microns. 1 ill.

Description

When automating technological processes, there is a need to change the temperature and their further processing. This requires high-precision, low-inertia transducers capable of withstanding high temperature loads in certain ranges.

The utility model relates to thermometry, namely to thermoelectric converters (TP) intended for their installation in temperature control devices in high-temperature technological processes. As a thermoelectric converter, thermocouples are widely used - differential devices that convert thermal energy into electrical energy.

The utility model can be used to measure the temperature of high-temperature processes in power engineering, metallurgy, chemical, oil, gas and other industries.

TP used for immersion temperature measurement are reactive devices consisting of a sensitive element (SE) with protective fittings (sleeve) of internal connecting wires and external leads that allow connection to electrical measuring devices.

In accordance with GOST 28537-90, a thermometric sleeve is an integral part of a technological device that separates thermoelectric converters from the substance being measured, protects against its action and provides installation.

When designing TP, such factors as the range of measured temperatures, aggressive properties of the medium in which measurements are carried out, thermal inertia and others are taken into account. This affects the way of connecting thermoelectrodes in the working junction, insulation of thermoelectrodes, protection of thermocouples.

In the general case, the TP design is represented by thermoelectrodes connected to each other in a working junction. Welded joints, withstand a wider temperature range. But at the same time, it is possible to change the characteristics of metals due to the influence of an aggressive environment. Oxidation or interdiffusion of materials may occur.

To increase the service life, the reliability of the submerged TP during their operation at high temperatures, in corrosive environments, good isolation of the sensitive element from the working environment is necessary.

There are many designs of protective reinforcement, which must ensure the strength characteristics of TP in accordance with the conditions of their use.

The design of a protective sleeve is known, made in the form of a part with a blind hole and including a working (submersible?) Part, a mounting element and a thermometer fastening element. In this case, the choice of the material from which the sleeve is made depends on the temperature range and chemical compatibility with the environment in which the device will operate.

The disadvantage of such a thermowell when measuring high temperatures is, as a rule, its rapid wear.

Known TP, in which protective sleeves are made of a tube, with a protective layer formed by plasma deposition of ceramics (Useful model RU No. 135128, IPC: H01K 7/00, publ. 27.11.2013).

Known TP for high-temperature and corrosive environments, containing a temperature-sensitive element in the form of a cable thermocouple and protective fittings made in the form of a metal cover muffled on one side, placed in an additional cover of graphite-containing material connected to it, which in turn is placed in a protective outer cover in in the form of a one-piece cast iron pipe (Utility model RU No. 100852, IPC: H01L 35/00, publ. 27.08.2010).

The disadvantage of this TP is the frequent need to measure the temperature in a wider range, the protective fittings are made of composite and the joints are destroyed under the influence of an aggressive environment.

Currently, to increase the service life of products, there is a method for improving the characteristics of materials - the technology of cold gas-dynamic spraying (CGN). The formation of coatings by the CGI method is carried out as a result of preliminary acceleration of the sprayed particles to supersonic speed and their collision with the substrate material, followed by plastic deformation. The use of fine powders helps to reduce the volume of microcavities and create a more uniform structure, which leads to an increase in corrosion resistance, hardness and adhesion of the coating.

The technical result of the proposed solution is the development of a TP design with increased resistance to aggressive media and high temperatures, therefore, their service life increases.

To increase the service life of the TP, it is proposed to apply a layer of aluminum with a thickness of 0.02 ... 0.05 mm by the method of gas-dynamic spraying on the submersible part of the TP and all welds. The formed intermetallic film of steel and aluminum will protect against corrosion.

The specified technical result is achieved due to the fact that the thermoelectric high-temperature converter with a sensitive element made of a metal wire, placed in a protective armature. Protective reinforcement is made of rolled metal tube and welded on one side. At the boundary of the immersed (working) part, which is in contact with the working medium, the temperature of which must be measured, a restricting washer is welded to the protective armature for installing the thermal converter at the temperature control object. The immersion part of the protective reinforcement, the welded seams and the part of the restraining washer interacting with the working medium are covered with an anti-corrosion layer of powdered aluminum, applied by cold gas-dynamic spraying, with the coating layer thickness ranging from 20 to 50 microns.

The utility model is shown in FIG. 1, where 1 is the protective armature of the thermoelectric high-temperature converter, 2 is the immersion part of the TP with a coating, 3 is the restrictive washer, 4 is the TP fastening element - the fitting.

The device works as follows. The thermoelectric converter is fixed on the object so that the immersion part 2 is in contact with the working medium, the temperature of which must be measured, and the fastening element of the thermometer 4 would be outside the working medium zone. The pre-submerged part (working part) of the protective armature with its welded seam, as well as the welded seam and the working part of the restraining washer welded to the protective armature, is covered with a uniform metal layer of aluminum powder. The thickness of this layer ranges from 20 to 50 microns. To apply the coating, the CGN technology of metals was used on the surface of parts. The gas flow velocity for the introduction of aluminum metal particles into the structure of the object (sleeve) is in the range from 1000 to 1200 m / s. The technology is realized with the help of portable universal equipment for manual work Dimet-405 produced by the Obninsk powder spraying center (OTsPN LLC).

The analysis of the service of thermoelectric converters, made with a coating with a layer of aluminum powder according to the CGN technology of all surfaces interacting with the working medium, the temperature of which must be measured, allows us to conclude about an increase in their service life.

Claims (1)

A high-temperature thermoelectric transducer with a sensitive element made of a metal wire, placed in a protective armature made of a metal tube, rolled and welded on one side, at the boundary of the immersion part in contact with the working medium, the temperature of which must be measured, a limiting washer is welded to the protective armature for installing a thermal converter at a temperature control object, characterized in that the immersed part of the protective reinforcement, the welded seams and the part of the limiting washer interacting with the working medium are covered with an anticorrosive layer of powder aluminum applied by cold gas-dynamic spraying, while the thickness of the coating layer is from 20 to 50 microns.

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