RU2431794C1 - Furnace for thermal treatment of large size items - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: furnace for thermal treatment of large size items consists of working chamber with pulse burners, of system supplying gaseous fuel and air with fans and controlled zone gas and air T-valves, and of smoke duct. The working chamber is equipped with a movable insulated partition with ratio of its volume (m3) to weight of load (t) as 2-3. Pulse burners of each zone are independently connected with systems of gas-air supply. Orifices for withdrawal of combustion products are made in an upper section of side walls of the working chamber. The said partition travels in lengthwise direction along the working chamber at a step multiple to length of a zone. ^ EFFECT: reduced specific flow rate of gas and exhausts of foul and greenhouse gases in atmosphere due to reduced heat losses caused with exhaust gases and for accumulation and furnace walling. ^ 2 dwg

Description

The invention relates to metallurgy, in particular to gas furnaces for heat treatment of large-sized products, for example blanks rolls of rolling mills with a wide range of sizes and masses of cages.

Known gas furnace for heat treatment of large products, containing a working chamber with pulse burners, a gaseous fuel and air supply system with fans and control zone gas and air valves, a flue system [1].

A disadvantage of the known furnace is the increased specific fuel consumption, which is due to the pulse mode of operation of the burners. During the shutdown period of the burners of all zones, a negative pressure is created at the furnace hearth level, as a result of which cold air is sucked into the furnace working space.

The closest adopted for the prototype is a gas furnace for heat treatment of large-sized products, containing a working chamber with pulse burners, a gaseous fuel and air supply system with fans and gas and air regulating zone valves with an exhaust hole, a smoke path in its lower part connected by a pipeline to the holes of three-way air valves [2].

The disadvantage of the prototype is the increased specific fuel consumption, the emission of harmful substances into the atmosphere during heat treatment of the charge of workpieces with a mass less than the nominal weight of the charge.

Under the conditions of, for example, nuclear, boiler, and petrochemical industries, the mass of product cages (blanks) is variable, since the product as a whole, as well as the workpieces and its components, are thermally processed.

A furnace for heat treatment of large-sized variable-weight products is proposed, comprising a working chamber with pulse burners, a gaseous fuel and air supply system with fans and regulating gas and three-way air valves and a smoke path, in which the working chamber is equipped with an insulated partition wall mechanically movable in the transverse direction with ensuring the ratio of its volume (m ³ ) to the mass of the charge (t), equal to 2-3, while the pulse burners of each zone are connected independently with the systems gas and air supply, and in the upper part of the side walls of the working chamber holes are made to remove combustion products.

In the proposed furnace, the said partition is also made with the possibility of moving in the longitudinal direction, along the working chamber with a step that is a multiple of the length of the zone.

In the proposed furnace for heat treatment of the charge of products (blanks) of variable mass due to the optimal ratio of the volume of the working chamber to the weight of the charge, heat losses with exhaust gases are reduced, due to accumulation and through the lining of the furnace, which reduces the specific fuel consumption and reduces harmful emissions (nitrogen oxides carbon monoxide) and greenhouse (carbon dioxide) gases into the atmosphere.

To explain the described invention, figure 1 shows a schematic diagram of a furnace, and figure 2 is a longitudinal section of a furnace.

The furnace consists of a working chamber 1, a thermally insulated partition with a mechanical drive 2, fans for supplying air to the pilot burners 3, fans for supplying air to the pulse burners 4, pulse burners 5, paired control zone three-way air 6 and gas 7 valves, automatic control systems including PLC (program logic controller) 8, thermal converter (temperature sensor) 9, control valve actuators 10, smoke vents 11, smoke collector 12, individual chimney (not shown).

The operation of the furnace during heat treatment of the charge of the nominal (maximum) mass is carried out according to option I. The partition when using 100% of the volume of the working chamber is in a fully raised state.

In options II and III, the partition is in the lower position. Moreover, in option II, for example, 67% of the volume of the working chamber is used, and in option III - 33% of its volume.

The operation of the furnace is as follows. A choice is made of the use of the working chamber on the basis of ensuring the optimal ratio of the volume of the working chamber (m ³ ) to the mass of the charge (t), equal to 2-3. Then the charge is loaded billets on under the furnace. After that, using a mechanical drive, the partition is installed in the position according to the selected use of the working chamber (see figure 2).

Then, the option of using the working chamber of the furnace and the heat treatment mode are set on the PLC and the furnace is started in automatic control mode.

On command from the zone temperature controllers, the opening of the zone twin air-gas valves is performed. After that, gas from the manifold and air from the fans enter simultaneously into all pulse burners of the zones that ensure the operation of the furnace in the selected embodiment. Further, in the tunnels of pulsed burners, the gas-air mixture of approximately stoichiometric composition of the nominal amount is burned. The combustion products are directed at a speed of 80 m / s into the working space of the furnace, providing conditions for uniform heating of the workpieces (products), and then they are sent through the holes in the upper part of the side walls to the smoke collector and are removed to the atmosphere using a metal chimney.

Adjustment of thermal power when performing the temperature regime of heat treatment is carried out due to the periodic on-off of pulse burners. At the same time, turning on and off the burners of each zone is performed independently.

In the proposed furnace for heat treatment of the charge of workpieces (products) of variable mass due to the optimal ratio of the volume of the working chamber to the weight of the charge, heat losses with exhaust gases, heat accumulation and through the lining of the furnace are reduced, which reduces the specific fuel consumption and reduces harmful emissions (oxides nitrogen, carbon monoxide) and greenhouse (carbon dioxide) gases into the atmosphere.

Information sources

1. Automated gas furnaces for heat treatment of products of nuclear power plants. M., NIIEnergoinformenergomash, 1978, No. 5-78-04, p. 35-49.

2. Copyright certificate SU 954755, cl. F27B 3/06. Date of publication - 02.09.82.

Claims (1)

A furnace for heat treatment of large-sized products, containing a working chamber with pulse burners, a gaseous fuel and air supply system with fans and regulating gas and three-way air valves and a smoke path, characterized in that the working chamber is equipped with a mechanically movable transverse direction insulated partition to ensure the ratio of its volume (m ³⁾ of the weight of cages (t) equal to 2-3, the pulse burner of each zone are connected independently with gas and systems vozduhop house, and in the upper parts of the side walls of the working chamber has openings for the removal of combustion products, wherein said partition is configured to move longitudinally along the working chamber with a pitch multiple of the length of the zone.

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