RU78309U1 - TEMPERATURE INSERT FOR CONTROL OF TEMPERATURE MODE OF SCREEN PIPES OF DRUM BOILERS - Google Patents

Abstract

The temperature insert for controlling the temperature regime of the screen tubes of drum boilers includes a transverse annular groove (3) with thermocouples installed in it (4), while the groove (3) with thermocouples (4) is fused with filler metal; the annular groove (3) is made in the annular surfacing (2), previously applied to the surface of the pipe (1); in the groove (3) at least three thermocouples (4) are placed, two on the frontal generatrix of the pipe, one on the rear generatrix; the groove (3) with thermocouples (4) is fused with silver solder (5). 2 ill.

Description

The utility model relates to the field of power engineering and can be used to measure the temperature of metal pipes of heating surfaces, mainly pipes of furnace screens of energy steam boilers.

The growth of deposits on the inner surface of the boilers is continuously monitored by measuring the temperature of the metal on the pipe wall. For its measurement, special temperature inserts are installed in screen tubes equipped with thermocouples. The design of the inserts is determined by the type of screen heating surfaces (screens of drum boilers, screens of gas-tight boiler units).

A device is known for measuring the temperature of metal pipes of furnace screens made of the same pipes as furnace screens, with longitudinal holes for installing thermocouples and a transverse annular groove for outputting them to the unheated side with a protective thin-walled ring on the outside, welded with a continuous seam to the pipe ( D.N. Kemmelman et al., “Adjustment of boiler units.” Reference, M, Energy, 1976, p. 98, fig. 4.1, p. 100, fig. 4.2).

A disadvantage of the known device is that the longitudinal holes and the annular groove in the pipe body weaken the pipe and shorten its service life. In addition, due to greater illumination and worse heat removal, the protective ring undergoes accelerated scale formation compared to the pipe, which leads to the destruction of the ring, a decrease in the strength of the pipe in the annular section and premature burning of thermocouples. Along with these shortcomings, welding of a thin-walled ring is a very complex technological operation.

The closest known device is “DEVICE FOR MEASURING TEMPERATURE OF METAL OF STEAM BOILER PIPES” (RF patent No. 42105, IPC 7 G01K 7/02, op. 2004.11.20, prototype), including a transverse annular groove with thermocouples installed in it, while part of the annular groove on the frontal forming pipe side in the 50 ° –60 ° sector is fused with filler metal along the arc, and the “hot” junctions of thermocouples are fixed in the groove right next to the weld metal on both sides.

A disadvantage of the known device adopted for the prototype is that the pipes can have technological defects in ellipse and wall thickness, sometimes exceeding the permissible ones, and after grooving the annular groove of a strictly specified size, their safety margin becomes less than the permissible value. In the same time

reducing the cross section of the annular groove to ensure strength is unacceptable due to the inability to lay the thermocouple in the groove.

The claimed solution allows to increase the reliability and strength of the device, without compromising the reliability of the measurement results and without resorting to the manufacture of devices from turned parts, including with a thickened wall.

This is achieved due to the fact that the temperature insert for controlling the temperature regime of the screen tubes of the drum boilers is a transverse annular groove made in an annular surfacing previously applied to the pipe surface with thermocouples installed in it, the groove with thermocouples is fused with silver solder.

According to a utility model, in order to increase the reliability of the temperature insert, at least three thermocouples are placed in the groove, two on the frontal generatrix of the pipe (one of which is backup), one on the rear generatrix.

Advantages of the model:

- good adhesion of silver solder to steel;

- high thermal conductivity of silver, providing speed and high accuracy of temperature measurements;

- fusion with silver does not damage the thermocouple, as the melting point of the solder is below the maximum operating temperature of the thermocouple;

- high manufacturability of the insert, which does not require surface treatment after melting;

- the durability of the model.

Figure 1 - temperature insert for pipes of drum boilers, section, General view;

figure 2 is the same, a section along the cross-section aa in figure 1.

The temperature insert for controlling the temperature of the screen tubes of the boilers includes a pipe - 1; surfacing - 2; groove - 3; thermocouple - 4; silver solder - 5.

On the outer surface of the pipe 1, annular surfacing - 2 is performed, then a groove 3 is machined in the surfacing to the base metal of the pipe 1. Three thermocouples 4 are laid in the groove 3: two on the frontal generatrix of the pipe, one on the rear generatrix. The thermocouple groove is fused with silver solder 5.

The device operates as follows.

The flue gases heat the pipe 1. As a result of heating the pipe 1 with “hot” junctions of thermocouples 4, fixed in the annular groove 3, thermopower appears in thermocouples 4 When connecting to the conductors of thermocouples 4 measuring device determine

the temperature of the pipe metal 1. Silver solder 5, covering thermocouples 4, which has high heat resistance and corrosion resistance to flue gases, on the one hand, protects the conductors from their effects, on the other hand, having constant tight contact with the surface of the groove, promotes heat dissipation, thereby reducing the temperature of the conductors and insulation of the thermocouples, which leads to an increase in the durability of the thermocouples 4.

Claims (1)

A temperature insert for controlling the temperature regime of the screen tubes of drum boilers, including a transverse annular groove with thermocouples installed in it, while the annular groove is fused with filler metal, characterized in that the annular groove is made in an annular weld, which is previously deposited on the surface of the pipe, in the groove at least three thermocouples, the ends of two thermocouples have an exit to the frontal generatrix of the pipe, the ends of the third thermocouple go to the rear generatrix of the pipe, while Application thermocouples zaplavlena silver solder.