JP2000297320A - Batch annealing furnace - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a batch type annealing furnace which not only can shorten a rising time (time constant of starting) but also has a high heat recovery rate. The high-speed switching regenerative combustion burner includes a furnace body of a batch annealing furnace, and a high-speed switching regenerative combustion burner. A plurality of combustors 23a and 23b, a four-way valve 24, and a communication pipe 2 for communicating the combustion air supply chamber 24a in the four-way valve with the combustor;
7 and combustion air supply pipe 25, and exhaust chamber 24 in the four-way valve
b and a communication pipe 28 for communicating the combustor with the exhaust pipe 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch annealing furnace for annealing mechanical parts.

[0002]

2. Description of the Related Art Conventionally, in a furnace for annealing or heating a machine part to be batch-processed, a furnace temperature of a burner furnace using heavy oil or the like is extremely high.

[0003] However, since heat recovery is not performed for batch processing, at present, combustion gas corresponding to the furnace temperature is directly discharged into the atmosphere. for that reason,
Energy is wasted considerably.

If a waste heat recovery device is installed in the burner furnace, it takes time to start and stop the entire device, which is inconvenient for a batch processing system. That is, when waste heat is recovered through a conventional heat exchanger, the heat recovery equipment has an excessive heat capacity, so that a so-called rise time is required, and a large amount of energy has to be consumed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and its object is to not only shorten the rise time (start time constant), but also An object of the present invention is to provide a batch annealing furnace having a high heat recovery rate.

[0006]

In order to solve the above problems, a batch annealing furnace according to the present invention comprises a furnace body of a batch annealing furnace and a high-speed switching regenerative combustion burner. A plurality of combustors, in which a heat storage type combustion burner includes a combustion burner and a heat storage body made of ceramic honeycomb,
Composed of a four-way valve, a communication pipe and a combustion air supply pipe communicating the combustion air supply chamber in the four-way valve with the combustor, and a communication pipe and an exhaust pipe communicating the exhaust chamber in the four-way valve with the combustor. Have been.

According to the present invention, the combustion air A that has passed through the combustion air supply chamber of the four-way valve passes through the first combustor, and has been heated to a high temperature in advance while being made of ceramic honeycomb. To become hot combustion air. When the fuel F is injected from the combustion burner into the high-temperature combustion air, it burns violently while mixing with the high-temperature combustion air, and becomes an ultra-high-temperature combustion gas G (about 1000 to 1200 ° C.), which is injected into the furnace body. .

On the other hand, the gas in the furnace heats a ceramic honeycomb regenerator while passing through the second combustor, and the exhaust gas G ′ (gas temperature, about 250 ° C.) is exhausted from a communicating pipe and a four-way valve. It is released to the atmosphere through the chamber and the exhaust pipe.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2,
The batch annealing furnace 1 includes a tunnel-shaped furnace body 10 and a high-speed switching-type regenerative combustion burner 20. Then, the workpiece B is carried into the furnace body 10 together with the carriage 30 and then annealed. And after being annealed,
It is carried out of the furnace body 10 by the carriage 30. The furnace body 10 is provided with opening and closing doors 11 at the entrance and exit, respectively.

On the other hand, a high-speed switching regenerative combustion burner 20
Is mainly composed of a first combustor 23a having a combustion burner 21a and a regenerator 22a made of ceramic honeycomb, a combustion burner 21b and a regenerator 22b made of ceramic honeycomb.
, And a four-way valve 24.

[0011] The four-way valve 24 is connected to the first combustor 23a.
, A communication pipe 28 communicating with the second combustor 23b, a combustion air introduction pipe 25, and an exhaust pipe 26.

Next, the operation of the high-speed switching type regenerative combustion burner 20 will be described. While passing through the first combustor 23a, the combustion air A passing through the combustion air supply chamber 24a of the four-way valve 24 is heated by the ceramic honeycomb regenerator 22a which has been heated to a high temperature in advance, and Becomes combustion air. When the fuel F is injected into the high-temperature combustion air from the combustion burner 21a, the fuel F burns violently while mixing with the high-temperature combustion air, and the ultra-high-temperature combustion gas G (about 100
0 to 1200 ° C.) and squirts into the furnace body 10.

On the other hand, the gas in the furnace body 10 is
3b while passing through 3b
b is heated and discharged into the atmosphere as exhaust gas G ′ (gas temperature, about 250 ° C.) through the communication pipe 28, the exhaust chamber 24 b of the four-way valve 24, and the exhaust pipe 26.

When the switching valve 240 of the four-way valve 24 switches from the position indicated by the solid line to the position indicated by the two-dot chain line, the combustion air A passing through the combustion air supply chamber 24a 'of the four-way valve 24
While passing through 3b, it is heated by the heat storage body 22b made of ceramic honeycomb, which is heated to high temperature, to become high-temperature combustion air. Combustion burner 2 in this high-temperature combustion air
When the fuel F is injected from the fuel gas 1b, the fuel F burns violently while mixing with the high-temperature combustion air, and the extremely high-temperature combustion gas G (about 1000
(About 1200 ° C.) and jets into the furnace body 10.

On the other hand, the combustion gas in the furnace body 10 heats the regenerator 22a made of ceramic honeycomb while passing through the second combustor 23a, and the exhaust gas G '(gas temperature, about 250 ° C.)
Are discharged into the atmosphere via the communication pipe 27, the exhaust chamber 24 b ′ of the four-way valve 24, and the exhaust pipe 26.

Hereinafter, a predetermined interval, for example, 20
Since the switching valve 240 of the four-way valve 24 switches at intervals of about 30 seconds, the inside of the furnace body 10 is maintained at a high temperature (about 1000 ° C.), and the workpiece B in the furnace body 10 is heated. After the workpiece B is heated to a predetermined temperature, the high-speed switching regenerative combustion burner 20 is stopped, and the workpiece B is gradually cooled to perform annealing.

As described above, the present invention provides a heat storage element
Since the ceramic honeycomb is used, the heat transfer area is large, compact, and high waste heat recovery efficiency can be obtained. That is, as compared with the ball-type heat storage element, the heat storage element volume ratio becomes about 1/5 and the weight ratio becomes 1/10. Further, the temperature efficiency becomes 90% or more (75% in the case of the ball type heat storage element).
Is). In addition, since the flow path resistance is low and the pressure loss is low, the pressure loss is about one-fourth that of the ball type heat storage element.

As shown in FIG. 3, the ceramic honeycomb D has a channel E formed of a straight straight honeycomb tube and performs self-cleaning once every 20 to 30 seconds with clean combustion air. There is no blockage. Balls and pellet regenerators need to be cleaned regularly because the flow stagnates and dust accumulates.

As described above, according to the present invention, the combustion air A that has passed through the combustion air supply chamber of the four-way valve has been heated to a high temperature in advance while passing through the first combustor. It is heated by the regenerator made of honeycomb to become high-temperature combustion air. When the fuel F is injected into the high-temperature combustion air from the combustion burner, the fuel F violently burns while mixing with the high-temperature combustion air, and the ultra-high-temperature combustion gas G (about 1000 to 1200).
° C) and squirts into the furnace.

On the other hand, the gas in the furnace heats the ceramic honeycomb regenerator while passing through the second combustor, and the exhaust gas from the communicating pipe and the four-way valve is exhausted as exhaust gas G '(gas temperature, about 250 ° C.). It is released to the atmosphere through the chamber and the exhaust pipe. Therefore, it has become possible to reduce the energy consumption by about half as compared with a conventional furnace without a waste heat recovery device.

[0021]

As described above, according to the present invention, the combustion air A passing through the combustion air supply chamber of the four-way valve is heated to a high temperature in advance while passing through the first combustor. It is heated by the regenerator made of ceramic honeycomb and becomes high-temperature combustion air. When the fuel F is injected into the high-temperature combustion air from the combustion burner, the fuel F burns violently while mixing with the high-temperature combustion air, and the ultra-high-temperature combustion gas G (about 1000 to 1200
° C) and squirts into the furnace.

On the other hand, the gas in the furnace heats the ceramic honeycomb regenerator while passing through the second combustor, and the exhaust gas G '(gas temperature, about 250 ° C.) is exhausted from the communication pipe and the four-way valve. It is released to the atmosphere through the chamber and the exhaust pipe.

Therefore, the present invention makes it possible to reduce the energy consumption by about half as compared with a conventional furnace having no waste heat recovery device, and is an industrially useful invention. Further, the present invention uses a ceramic honeycomb heat storage body, so that the heat transfer area is large, compact, and high waste heat recovery efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view including a partial cross section of a batch annealing furnace according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view of a ceramic honeycomb.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Batch-type annealing furnace 10 Furnace body 20 High-speed switching type regenerative combustion burner 21a, 21b Combustion burner 22a, 22b Regenerator 23a, 23b made of ceramic honeycomb Combustor 24 Four-way valve 24a Combustion air supply chamber in 4-way valve 24b Exhaust chamber in four-way valve 25 Combustion air supply pipe 26 Exhaust pipe 27, 28 Communication pipe

Claims (1)

[Claims] 1. A plurality of combustors each comprising a furnace body of a batch annealing furnace and a high-speed switching type regenerative combustion burner, wherein the high-speed switching type regenerative combustion burner comprises a combustion burner and a ceramic honeycomb regenerator. A communication pipe and a combustion air supply pipe communicating the combustion air supply chamber in the 4-way valve with the combustor, and a communication pipe and an exhaust pipe communicating the exhaust chamber in the 4-way valve with the combustor. Batch annealing furnace.