SU1223000A1 - Continuous muffle furnace - Google Patents

Description

The invention relates to powder metallurgy, in particular to pass-through muffle furnaces for annealing metal powders and sintering products from powders, and can be used in mechanical engineering for non-oxidative heat treatment of metal.

The aim of the invention is to increase the efficiency and improve the quality of heating the billet by organizing the movement of high-temperature flows above and below the billet and rational post-combustion and mixing of the gas components of the sintering powders.

FIG. 1 shows a diagram of a muffle through furnace; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows a section BB in FIG. 2

The passage muffle furnace has a hermetic muffle 1 combining chambers 2-4 (heating, holding and cooling, respectively), charging device 5, heating burners 6, unloading chamber 7, driving device 8 and process gas inlet system 9. The device 10 for utilizing the heat of exhaust gases is connected in its lower part by thermally insulated chimneys 11 to the furnace space 12 of the heating chamber, in the upper part of the device there is a mixing chamber 13 and a lattice intermediate roof 14 (Fig. 2). The lower and upper parts of the disposal device are connected by vertical bypass channels 15 with integrated injection mixers 16 connected to the air manifold 17. At the charging end, the disposal device is equipped with a discharge pipe 18, at the base of which an ejector 19 and a flexible curtain 20 are installed. and in zone 21 unloading. The main gates 23 are installed on the smoke exhaust channels 22 of the heating and holding chambers, and on the basis of the additional recycling chamber the refractory columns 24.

The furnace works as follows.

Turning on the drive 8 drives the furnace transport device. The heating burners 6 of the heating chamber 2 and the furnace holding chamber 3 are ignited, the ejector is turned on at the loading and unloading, after the furnace is blown with an inert gas by opening the valve at the process gas inlet 9, which is divided into two diametrically opposite flows, which one moves in the direction of the transporting device through the working and refrigeration chambers to the unloading chamber, and the other moves in countercurrent through the heating chamber 2 to the device 10 for disposal heat

After the output of the furnace to the mode of loading device 5 serves the product on a trans

porting device, cover the main spindle 23 of the furnace on channel 22 to remove heating flue gases from the heating chamber 2 of the furnace and thus direct hot exhaust flue gases with a temperature of 600-700 ° С from the heating space 12 through the insulated chimney 11 to the hollow lower the part of the additional chamber, where the hot flue gases are evenly distributed by the columns 24 (Fig. 3) and, in direct contact, release their heat to the transport device with the material on it. The cooled flue gases are sucked in vertical bypass channels 15 by injection mixers 16, into which fan air is supplied from the air collector 17, and mixed with air in the mixing chamber 13. The mixture of exhaust flue gases and air is evenly distributed to the lattice intermediate

vault 14 above the material.

The waste process gas from the heating chamber enters the device for utilization and burns enough hot flue gases and air in the mixture stream in the mixture stream and transfers its heat to the material in direct contact. In the process of heating the products, the decomposition products of solid lubricants emitted from them also burn, releasing heat.

The air supply to the air collector 17 is regulated to the incomplete combustion of the process gas, therefore, the gaseous medium over the products in the disposal device is slightly reducing, oxidation of the processed material does not occur, which improves the quality. The confirmation of the presence of a weakly reducing atmosphere in the disposal device is a slight burning at the exhaust pipe 18. The uneven post-combustion of the process gas is eliminated,

since the combustion takes place in a mixture of air with flue gases, the rate of burning of hydrogen is quenched.

In addition, the flue gases coming from the furnace furnace space to the recycling device, and the combustion products from the flue process gas create a gas curtain that prevents the penetration of air oxygen into the muffle's internal working space. In contrast to the known, the furnace of the proposed design provides intensive uniform heating of the material with a given quality even at the first stage of the process, while in the furnace of the proposed design the formation of a gas curtain on loading and the implementation of internal heating

material with the formation of a weakly reducing gaseous medium is achieved not by burning an additional amount of natural gas, but due to the afterburning

exhaust process gas and the use of heat from the exhaust flue gases from the heating space of the furnace.

Hence, additional energy savings are evident, while maintaining the high quality of the material as a result of introducing the proposed invention into the powder metallurgy industry.

Thus, the invention provides uniform and accelerated heating of the material due to the organization in the device for the disposal of the flow of exhaust gases - hot and up to

Zhigayush, its technological - from different sides, uniformly heating the material; stable quality of the material due to the organization in the device for utilization of a weakly reducing gaseous medium, which is removed along countercurrent with the material; increasing the efficiency of heat utilization of waste heating and process times and creating a protective curtain without additional consumption of natural gas.

All these advantages allow to increase the efficiency of the furnace as a whole and to improve the quality of heating the blanks.

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FIG. 2

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Compiled by V. Smirnov

Editor I. NikolaichukTehred I. VeresKorrektor O. Lugova

Order 1697/40 Circulation 561 Subscription

VNIIPI USSR State Committee

for inventions and discoveries

113035, Moscow, Zh-35, Raushsk nab. 4/5

Branch PPP "Patent, Uzhgorod, st. Project, 4

Fig.Z

Claims (1)

PASSING MUFFLE FURNACE, comprising series-connected heating and holding chambers with gas burner devices and smoke exhaust channels made in the lining, a cooling chamber and ejectors, characterized in that, in order to increase the efficiency and improve the quality of heating the workpieces, it is equipped with an additional lined chamber with the hearth installed in front of the heating chamber and connected to it in the lower part by means of smoke exhaust channels, the additional chamber has an intermediate perforated arch forming with the arch a mixing chamber connected to the sub-chamber space of the chamber by bypass channels located in its side walls, with ejectors installed in the side walls above the outlet of each bypass channel into the mixing chamber, and rows of refractory columns are placed on the base of the additional chamber. Figure 1