JPH05357B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a soaking method for firing ceramic products.

(Prior Art) When firing a ceramic product, as shown in FIG. A method of firing while injecting combustion gas 30 and exhausting it from the exhaust hole 23 in the ceiling is widely known. FIG. 5 shows an example in which such a conventional method is applied to a tunnel furnace. FIG. 5A shows a firing zone, and FIG. 5B shows a cooling zone. However, in this conventional method, in the firing zone, the direction of the upward flow generated at the location where the combustion gases from the burners 21 and 22 collide coincides with the direction of the buoyancy of the gas, and the buoyancy has an effect of promoting the formation of the upward flow. However, since the burners 21 and 22 blow out gas at a lower temperature than the atmosphere in the furnace in the cooling zone, the buoyant force acts downward and inhibits the formation of an upward flow in the furnace. For this reason, although a good circulation flow is formed in the furnace in the firing zone and the atmosphere in the furnace is kept uniform, in the cooling zone the circulation in the furnace is not sufficiently performed and uneven cooling tends to occur.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and eliminates uneven firing and cooling by forming a uniform circulating flow in the furnace not only during firing but also during cooling. This method was developed with the aim of creating a uniform heating method that can prevent the occurrence of

(Means for Solving the Problems) The present invention periodically adjusts the jetting speed during firing so that the collision position of gas in the furnace moves in the width direction of the furnace from a plurality of burners installed at opposing positions on both sides of the lower part of the furnace body. Firing is performed while ejecting combustion gas from the top while changing the ejection speed, and during cooling, combustion gas is ejected from multiple burners installed on opposing sides on both sides of the upper part of the furnace body while periodically changing the ejection speed. It is characterized by cooling while exhausting air from the bottom.

(Example) The present invention will be described in more detail below along with an illustrated example in which the present invention is applied to a tunnel furnace. Figure 1 A, B
1 are cross-sectional views showing the firing zone and cooling zone, respectively.
2 is a furnace body of a tunnel furnace, 2 is a truck, and 3 is an exhaust hole with a damper 4 formed in the ceiling of the furnace body 1.
As shown in FIG. 1A, a plurality of burners 5 and 6 are provided facing each other on both sides of the lower part of the furnace body 1 of the firing zone, and high-temperature combustion gas is emitted from each burner 5 and 6 as shown by the arrows. It is squirted. The ejected combustion gas generates an upward flow at the collision position and is exhausted from the exhaust hole 3 in the ceiling. At this time, the combustion gas has a higher temperature than the atmosphere in the furnace, so it produces an upward buoyant force, but since the direction of this buoyant force is the same as the direction of the upward flow, a good circulating flow is formed inside the firing zone. . Moreover, in the present invention, by periodically changing the ejection speed of the combustion gas from the burners 5 and 6, the gas collision position, that is, the position where the upward flow is formed, is periodically moved in the furnace width direction. This state is schematically shown in Fig. 2, and Fig. 2A shows a state in which the ejection velocity from burner 6 is higher than the ejection velocity from burner 5, and an upward flow is formed in the left part of the furnace. , FIG. 2C shows the opposite state, and FIG. 2B shows an intermediate state between the two. It is assumed that in any state, the sum of the amount of gas ejected from burner 5 and the amount of gas ejected from burner 6 is kept constant. In this way, the position where the upward flow is formed is periodically moved in the width direction of the furnace, thereby making the temperature distribution in the furnace even more uniform.

Further, as shown in FIG. 1B, in the present invention, the furnace body 1 of the cooling zone is provided with a plurality of burners 7 and 8 at opposing positions on both sides of the upper part.
Exhaust pipes 9 and 10 are provided on both sides of the lower part. Combustion gas is ejected from these burners 7 and 8 in the same manner as described above, and a downward flow as shown in the figure is formed at the collision position. As mentioned above, in the cooling zone, combustion gas having a lower temperature than the atmosphere in the furnace is ejected, so that the buoyant force acts downward, which corresponds to the direction of this downward flow. Therefore, according to the present invention, a good circulating flow is also formed inside the cooling zone. Moreover, even in the cooling zone, the ejection speed of combustion gas from burners 7 and 8 is periodically changed, and the collision position where the downward flow is formed is periodically changed in the width direction of the furnace. The internal temperature distribution is also made uniform, and a uniform fired product without uneven cooling can be obtained. At this time, the exhaust hole damper 4 on the ceiling may be closed, but outside air may be sucked in to promote cooling.

As mentioned above, in the present invention, the burners 5 and 6
The collision position is moved in the width direction of the furnace by periodically changing the ejection speed of the gas from 7 and 8.As shown in FIG. The same change is applied to each side at the same time, and the collision position is a straight line L ₁ parallel to the furnace body 1,
Normally, control is performed so that they are located sequentially on L ₂ and L ₃ . However, in another embodiment of the present invention, as shown in FIG. changing straight line
It is controlled to be located above L ₄ , L ₅ , and L ₆ .

Although the embodiments described above all apply the present invention to a tunnel furnace, the present invention can also be practiced using a single furnace. In this case, burners may be provided above and below the furnace body 1, and combustion gas may be ejected from the lower burner during firing, and may be ejected from the upper burner during cooling.

(Effects of the Invention) As is clear from the above description of the embodiments, the present invention provides the direction of the buoyant force acting on the ejected gas and the collision position by changing the ejecting position of the combustion gas during firing and cooling. Not only can a good circulation flow be formed in the furnace by aligning the flow direction of the ejected gas in the furnace, but also the temperature distribution in the furnace can be improved by moving the collision position of the combustion gas in the width direction of the furnace. This resulted in further uniformity. Therefore, according to the present invention, the temperature distribution in the furnace can be made uniform not only during firing but also during cooling, and fired products without uneven firing or cooling can be obtained.
Therefore, the present invention greatly contributes to the development of industry as a soaked firing method that eliminates the problems of the conventional method.

[Brief explanation of the drawing]

A, B in FIG. 1 are sectional views showing an embodiment of the present invention, A, B, and C in FIG. 2 are sectional views showing its operating state, FIG. 3 is a plan view thereof, and FIG. A plan view showing another embodiment, and A and B in FIG. 5 are both sectional views showing a conventional example. 1... Furnace body, 5, 6... Burner, 7, 8...
burner.

[Claims]

1 In a method of instantaneously heating a sample to be heated, the sample is wrapped in or brought into contact with a mixed compact consisting of nickel powder and titanium powder, and the sample is rapidly externally heated under reduced pressure. An instantaneous heating method characterized by inducing a self-heating reaction in the green compact and instantaneously applying heat higher than an external heating temperature to the sample.