JPS6326175B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for operating a batch type atmospheric heat treatment furnace using radiant tube heating.

Generally, an atmospheric gas is used to subject metals to non-oxidation or bright heat treatment, but the atmospheric gas has been transformed using a known gas generator.
However, when fuel is burned at an air-fuel ratio of 1 or less, reducing or non-oxidizing combustion exhaust gas is obtained, so the combustion exhaust gas from the radiant tube installed in the heating chamber is cooled and moisture is removed before entering the heating chamber. Conventionally, it has been carried out to supply gas and use it as an atmospheric gas. In that case, when heating the object to be heated rapidly, a large amount of combustion exhaust gas can be supplied from the radiant tube to the heating chamber, but during subsequent soaking or slow cooling, the energy required to maintain the temperature of the heating chamber is insufficient. Since replenishment is sufficient, only a small amount of combustion exhaust gas can be obtained since the combustion of the radiant tube is reduced. Therefore, in the past, atmospheric gas had to be supplied from the outside during soaking or slow cooling, and a gas generator for this purpose was still required as ancillary equipment.

The present invention has been made in view of the above, and includes a tank that stores a part of the combustion exhaust gas discharged from the radiant tube in a compressed state, and a large amount of combustion exhaust gas discharged from the radiant tube during heating is transferred to the tank. By storing the combustion exhaust gas in the tank and releasing it into the heating chamber during soaking,
This enables batch-type operation of atmospheric heat treatment without the need for a gas generator.

Embodiments of the present invention will be described below with reference to the drawings.
In the equipment of the atmospheric heat treatment furnace shown in FIG. 1, 1 is a heating chamber, 2 is a cooling chamber, 3 is a radiant tube disposed within the heating chamber, and 4 is a burner provided at one end of the radiant tube. The radiant tube 3 radiates radiant heat into the heating chamber 1 and heats a heated object (not shown) in the heating chamber 1.
The fuel is combusted at an air-fuel ratio of 1 or less, and the combustion exhaust gas is led to a cooler 5, cooled and dehydrated, and then branched and supplied into the heating chamber 1 and the cooling chamber 2 through a valve 6 and an air supply pipe 7. 8 is a tank, and 9 is a compression pump, which compresses a part of the combustion exhaust gas discharged from the cooler 5 so that it can be stored in the tank 8. Reference numeral 10 denotes a valve provided on a discharge pipe 11 of the tank 8, which communicates with the air supply pipe 7. Therefore, when heating is performed by intensifying the combustion of the radiant tube 3 in order to raise the temperature of the object to be heated in the heating chamber 1, a portion of the combustion exhaust gas discharged from the radiant tube 3 in large quantities operates the compression pump 9. and stored in the tank 8 in a compressed state. When the combustion of the radiant tube 3 is reduced during soaking or slow cooling in which the temperature of the heated object is maintained for a certain period of time after it has risen to the desired temperature, the valve 10
It is opened to release combustion exhaust gas from the tank 8 into the heating chamber 1 and the cooling chamber 2 through the air supply pipe 7.

Figure 2 shows high-temperature combustion exhaust gas discharged from the radiant tube 3 and the heating chamber 1 via the air supply pipe.
An example is shown in which a heat exchanger 12 is provided to exchange heat with low-temperature combustion exhaust gas supplied to the engine, and other configurations are the same as the embodiment shown in FIG. In this case, the temperature of the combustion exhaust gas supplied to the heating chamber 1 can be increased, which is an effective means for saving energy.

Depending on the object to be heated and the purpose of its heat treatment, the cooler 5
A CO ₂ removal device is installed immediately after.

As explained in the embodiments above, the method for operating an atmospheric heat treatment furnace according to the present invention stores a part of the combustion exhaust gas of the radiant tube in a compressed state in a tank,
Since the combustion exhaust gas stored in the tank can be used as atmospheric gas even when the combustion of the radiant tube is reduced during soaking or during slow cooling, an expensive gas generator is not required even in batch type operation. This has beneficial effects, such as eliminating the need for equipment and reducing equipment costs, as well as eliminating the cost of fuel consumed by gas generators.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an atmospheric heat treatment furnace showing one embodiment of the present invention, and FIG. 2 is a system diagram showing another embodiment. 1...Heating chamber, 2...Cooling chamber, 3...Radiant tube, 5...Cooler, 6...Valve, 7...
... Air supply pipe, 8 ... Tank, 9 ... Compression pump, 1
0...Valve.

Claims (1)

[Claims] 1 In a batch type atmosphere heat treatment furnace in which a radiant tube is disposed in a heating chamber, combustion is performed in the radiant tube at an air-fuel ratio of 1 or less, and the combustion exhaust gas is supplied into the heating chamber, the radiant tube is discharged from the radiant tube. A tank is provided to store part of the combustion exhaust gas in a compressed state, and the combustion exhaust gas discharged in large quantities from the radiant tube during heating is stored in the tank, and the combustion exhaust gas in the tank is transferred to the heating chamber during soaking or slow cooling. 1. A method for operating an atmospheric heat treatment furnace, characterized in that: