SU881495A1 - Chamber furnace - Google Patents

Description

The invention relates to heating and heat-treating furnaces used in plants of the metallurgical and machine-building industry. A well-known chamber furnace with external mechanization for heat treatment of garden steel products, consisting of a heating chamber of rectangular cross section, a loading window, a lockable lifting flap and a number of transversely located ( with respect to the heating chamber of the underfloor recirculation furnaces with burners l There is a shortage of furnace current in that between the frame of the loading window, the threshold of the furnace and the dampers In the closed state, there remain gaps through which cold air is drawn into the lower part of the furnace, cooling the front end of the condensate, therefore the latter is unevenly heated and the quality of the metal does not always meet the requirements. The closest to the proposed one is heating chambers, a loading window with a damper and a number of recirculation furnaces with a two-step recirculation of combustion products. The first one from the loading window of the furnace (just like the other furnaces of the furnace contains a stepped furnace tunnel with an increase in the cross section from step to step along the gas flow, and the recirculation channels are connected to the beginning of each step, and the cross section of each step is 1.5 -2.0 times the corresponding cross-sectional area of the previous stage, and the area of each recirculation and exit channel is not less than the cross-sectional area of the corresponding heating tunnel entrance. and the furnace proceeds in the following way. Under the influence of the jet of combustion products at the beginning of each stage, a negative pressure is created in the combustion tunnel due to a sudden change in the cross section. The furnace gases from the working space and cold air, entering through the leakage window of the loading window,: are injected into recirculation channels into the furnace .tunnel. A mixture of furnace, flue gases and air enters from the furnace to the furnace along the outlet channel. This stream also picks up some of the cold air entering the furnace.

Through the looseness of the boot eye, mixed with it and then goes and the heating of the charge fZ}

The disadvantage of the known furnace is that after a period of time between recirculation and OUTPUT VALVES, part of the cold air proyaket to the front end of the charge, and as a result, it is unevenly heated.

. The purpose of the invention is to increase the heating uniformity of the charge. 10

The goal is achieved by the fact that the recirculation and output channels of the first subfloor furnace from the loading window are expanded towards the loading window, and under furnace 15 beyond the threshold plate has recesses across the width of these channels between transport tracks.

1 shows schematically a furnace, a longitudinal section of D-A in FIG. 3; 20 in Fig. 2, section B-B in Fig. 1; on fig.Z - section bb In figure 1.

The furnace has a heating chamber 1, under 2, underfloor furnaces 3 and a burner 4. A recirculation channel 5 is connected to the first half of the furnace, and a recirculation channel 6 is connected to the second part of the furnace. The end of the furnace is connected to the heating chamber by outlet 7. The recirculation channels and the exit channel are expanded 30 in the direction of the loading opening 8, closed by the valve 9. Under the furnace beyond the threshold plate 10, on the sides of the transport tracks 11, there are recesses 12.35

The movement of gases in the furnace is as follows.

The air-fuel mixture, which flows out of the burner 4, burns in the first half of the under-floor JQ ki 3 and sucks the gases from the heating chamber 1, including cold air, which enters the furnace through the leakiness of the side of the loading window 8 through the recirculation channel 5. The temperature of the flare decreases and the storage does not overheat. The mixture of fresh combustion products and gases sucked through the recirculation channel 5 when moving into the second half of the subfuel insert 3 as a result of a stepwise expansion of the latter, again sucks the gases from the heating chamber 1, including cold air entering the furnace between the valve 9 and the threshold plate 10. A mixture of 55 gases from the underfloor furnace 3 enters the heating chamber 1 through the exit channels 7 and, in turn, draws cold air into the furnace through the side gap between the valve 9 and the loading window 8. Cold Air entering the furnace through the tightness of the loading window 8, as a heavier gas, first flows from the threshold plate 10 and transport tracks 11 into recess 12. From these depressions, it is removed by flows of recirculation channels 5 and 6 and exit channel 7, where mixed with furnace gases.

The temperature of the mixture of gases entering the heating chamber 1 from the channel 7 | entrance and heating tanks going to heat (measured with a thermocouple under the furnace roof and maintained at a predetermined level by controlling fuel consumption. Expansion of the suction recirculation channels 5 and 6 A 7 exit in the direction of the loading window 8 allows these channels to be brought closer to the working window area and to completely remove the cold air from there.

In this way, the cooling effect of the cold air penetrating through the leaks of the loading window to the front end of the load is eliminated. The charge heats up more evenly, equalization of temperatures occurs faster, which leads to an increase in furnace productivity and a decrease in specific fuel consumption.

The positive effect from the introduction is obtained due to the increase in furnace productivity, reduction of specific fuel consumption and increase in product quality.

Claims (2)

1. Krivandin V.A. Markov B.L. Metallurgical furnaces. M., Metallurgists, 1977, p. 377-378, fig. 171. 2. Project of a thermal recirculation furnace with external mechanization. Drawing 4-33002-ЗСВ, Chel bgipromez, 1972. .i 5V B- B / g 9 10