SU1136037A2 - Device for determination of furnace operation temperature precision - Google Patents

Abstract

DEVICE FOR DETERMINING THE TEMPERATURE ACCURACY OF WORK OF FURNACES on the author. St. No. 1051390, characterized in that, in order to simplify the construction of the device, its inner surface is partially lined at the locations of the thermocouples, and the size of the lined area around each thermocouple installation point is determined from the relation R where R is the distance from the location of the thermocouple spa to the border of the lined surface area; 8 L - steel sheet thickness; -thermal conductivity of steel sheet; - total heat transfer coefficient by convection and radiation from the surface of the model set to the working space of the furnace in the operating temperature range. (L 00 05 about with

Description

The invention relates to thermometry, in particular to devices for testing chamber furnaces with the aim of determining the temperature accuracy of their operation.

According to the main author. St. No. 1051390 is known a device for determining the temperature accuracy of operation of furnaces, containing a model load, made in the form of a low-inertia steel structure with thermocouples, the inner surface of which is lined with a fiber-refractory material.

The device achieves increased measurement accuracy by eliminating the influence of non-radiation of heat flux from the walls of structure 1.

A disadvantage of the known device is that in order to achieve increased accuracy in it, the entire inner surface of the structure is lined, which requires a significant consumption of lining material.

The purpose of the invention is to simplify the construction by reducing the consumption of lining material.

This goal is achieved by the fact that in the device for determining the temperature accuracy of operation of furnaces, its inner surface is partially lined at the locations of thermocouples, and the size of the lined area around each thermocouple installation point is determined from the ratio

.

R 4

where R is the distance from the location of the thermocouple spa to the boundary of the lined surface area;

S is the thickness of the steel sheet;

L - coefficient of thermal conductivity of steel sheet;

сА - total heat transfer coefficient by convection and radiation from the surface of the model set to the working furnace production in the working temperature range.

FIG. 1 shows a device for determining the temperature accuracy of operation of furnaces, a general view; in fig. 2 - model set, cross section.

The model cell consists of a body 1 made of steel sheets and provided with stiffening ribs 2. Thermocouples 3 are installed on the surface of the body. Model cage installed on supports 5 and. placed on the bottom 6. The overall dimensions of the model pool coincide with the overall dimensions of the maximum cage processed in the furnace.

The device works as follows. After heating the furnace in an oven and isothermal exposure, the temperature distribution determined by thermocouples is established on the surface of the charge.

The operation of the device is considered by the example of testing a chamber heat-treating furnace designed to process a cage with dimensions of 4x10x2 m in the temperature range of 500-900. Body model

 The tanks are made of stainless steel sheet with a thickness of 4x10 m, with a thermal conductivity coefficient of jl 25 W / (mK). The number of installed thermocouples N 24. The size of the lined section according to the experimentally obtained formula is

/

252MjLjn ± .. LOO

0.12 (m)

MKRV-200 plates are used for lining (application temperature up to 1150 ° C). The standard plate size is BOOX X1500x40 mm, one such plate is sufficient for lining the surface of 12 thermocouples (the lining size for one thermocouple is 300x250 mm). The total consumption of the lining material 2 plates, with a total area of 1.8 Mf, is the total area of the inner surface of the model load in this example, about 130 m.

The actual dimensions and configuration of the lined areas in each case is determined on the basis of the inequality R 4 V - ,, and, based on the relative position of the thermocouples and the dimensions of the plates of the lining material.

For example, if any of the thermocouple junctions are located on the surface of a model mount n a distance less than the specified size, then for structural considerations it is advisable to make the lining of the inner surface of the charge for these thermocouples with one piece of lining material plates. In this connection, it is not advisable to indicate for a value of R any particular upper limit.

The use of the invention will significantly reduce the cost and laboriousness of the manufacture of a device for determining the temperature accuracy of operation, due to the saving of the lining material.

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AA / JX J WW

five

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Claims (1)

DEVICE FOR DETERMINING TEMPERATURE ACCURACY OF OPERATIONS OF FURNACES by ed. St. No. 1051390, characterized in that, in order to simplify the design of the device, its inner surface is partially lined at the locations of the thermocouples, and the size of the lined area around each installation point of the thermocouple junction is determined from the relation where R is the distance from the location of the thermocouple junction to the boundary lined surface area; S — thickness of the steel sheet; Λ is the thermal conductivity coefficient of the steel sheet; Y, _ the total coefficient of heat transfer by convection and radiation from the surface of the model cages to the working space of the furnace in the working temperature range. I SU „„ 1136037>