JPH07101155B2 - Furnace pressure holding device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a heating furnace or a metal processing furnace.
In-furnace pressure holding device.

[0002]

2. Description of the Related Art For example, as shown in Japanese Patent Publication No. Sho 58-19623, the furnace temperature is lowered to about 900 ° (sometimes about 850 °) while the baked roof tile materials are piled up in a heating furnace. After that, supply a predetermined amount of propane gas to the furnace without burning it and give it a black smoked color.
Fumigation tile manufacturing method for a natural cooling (or forced cooling) to are known. Further , it is known that in a heating furnace, a metal product heat-treated in a reducing atmosphere in the furnace is naturally cooled or forcedly cooled without invading outside air . However , the doors etc. that shut off the inside and outside of the heating furnace are
Outside air it is impossible to produce by sea urchin precisely does not enter. Therefore, reduction furnace pressure with cooling Then, there is the quality of the oxidizing ambient air from entering tile fumigation film partially and is impaired, or by contacting the outer air to the metal products in the heating furnace before extraction after cooling There are drawbacks such as taking out defective products. This defect is caused by the fact that the furnace internal pressure becomes lower than the external atmospheric pressure as the heating furnace is cooled.

[0003] To eliminate this drawback, but the above-described solution means the furnace pressure by supplying carbon dioxide gas into the furnace from the carbon dioxide gas cylinder together with the cooling start holding higher than the outside air pressure is taken, this means, in every moment It was not possible to control the amount of carbon dioxide gas to be changed in response to the changing furnace pressure, and consuming carbon dioxide for a long time until the completion of cooling had a new drawback of increasing costs . .

Further , a metal treatment furnace for heating a furnace by means of a radiant tube burner mounted inside, and filling the furnace with a treated metal such as a coil having a large diameter for wire drawing and performing annealing is provided inside the furnace. since the outside air is filled, accommodating the treated metal d of the coil such that you do not want to oxidize, the put in the furnace lid b sand seal c oxidation prevention case a as illustrated in FIG. 6 Is normal. The metal treatment furnace is composed of a huge furnace body having a side length of about 3 to 2.5 M, and an oxidation prevention case a with a lid for containing treatment metal such as copper and iron coil is also included.
Since it becomes large, it is necessary to simply remove the atmosphere (oxidizing gas) from the inside of the furnace in order to abolish the use of this case. However , in reality, no measures are taken into consideration.

[0005]

The object of the present invention is to heat
Sending combustion exhaust gas in a reducing atmosphere into the furnace or metal processing furnace
Keep the furnace in a reducing atmosphere at a pressure higher than the atmospheric pressure.
To provide a device that prevents outside air from entering.
It is in.

[0006]

According to the invention of claim 1 of the internal pressure holding device of the present invention , baking of roof tile material and black smoldering are combined.
A small combustion chamber outside the heating furnace for smoked roof tile production
Provided, the gas fuel or gasified fuel is supplied together with the combustion air to the combustion chamber, or combustion exhaust gas a reducing atmosphere generated by burning a mixture gas mixed with the combustion air by supplying oxygen insufficiency, tile dough Slow cooling after heating and smoking
Sometimes by feeding into the heating furnace, the outside pressure the heating furnace
It is characterized in that it is configured to be maintained in a reducing atmosphere with a higher pressure .

According to a second aspect of the present invention, a heat treatment furnace for heating by mounting a radiant tube burner is filled with a treatment metal such as a coil, and a small combustion chamber is provided outside the heat treatment furnace. changing the provided gas fuel or gasified fuel is supplied together with the combustion air to the combustion chamber, or generated by a mixed gas with the combustion air supplied to combustion in an oxygen deficient state
The combustion exhaust gas of the original atmosphere by feeding the heat treatment furnace before the filling of the treated metal and is characterized by being configured to hold a furnace to a reducing atmosphere of higher than the outside atmospheric pressure the pressure.

[0008]

According to the invention of claim 1, a small combustion chamber 11 is attached to the outside of the heating furnace 1, and a gas fuel or a gasified fuel is supplied to the combustion chamber 11 together with the combustion air, or a mixed gas is mixed with the combustion air. Is generated and burned in an oxygen-deficient state
By feeding has been the flue gas water vapor mixture a reducing atmosphere in said heating furnace 1, a decrease in furnace pressure due to the cooling of the heating furnace 1 is prevented, the heating furnace 1, a pressure higher than the pressure in the furnace Is kept at a pressure that prevents outside air from entering . others
Therefore , for example, to prevent deterioration of quality due to surface oxidation of smoked roof tiles .
You can

According to a second aspect of the present invention, a U-shaped radiant tube burner 32 is provided inside the heat treatment furnace 31,
Inside the heat treatment furnace 31, an annealed metal product such as a large-diameter coil or other metal product is inserted without using a case as in the conventional case. A small combustion chamber 11 which is the same as the combustion chamber 11 of the invention of claim 1 is attached to the outside of the heat treatment furnace 31, and gas fuel or gasified fuel is supplied to the combustion chamber 11 together with combustion air or mixed with combustion air. the flue gas water vapor mixture of the mixed gas is supplied are generated by the combustion in the oxygen-deficient state reducing atmosphere, is fed into the pre-heating of the treated metal product heat treatment furnace 31, heat treatment furnace 31 in the furnace Is kept in a reducing atmosphere at a pressure higher than the atmospheric pressure .
It Therefore, even when the combustion of the radiant tube burner is interrupted due to annealing, for example , in the heat treatment furnace 31.
Is the outside air that is kept at a pressure higher than the outside pressure and has oxidant.
But do not enter.

[0010]

1 and 2 show an embodiment of the invention according to claim 1 of the present invention, and FIG. 1 shows a heating furnace 1 for producing a smoky tile for continuously baking and baking a tile material and black smoldering. The firing of the roof tile material (not shown) stacked in the furnace is performed by igniting a propane gas combustion flame from a number of gas burners 2 provided in the furnace body of the heating furnace 1 to about 8 to 8
Charge for 10 hours, heat up to around 1050 ° C, and then seal the outside from the burner port 3 so that no outside air enters the furnace. When the furnace temperature reaches 900 ° C. to 850 ° C., a predetermined amount of raw propane gas that is not burned is supplied from a large number of gas supply pipes 5 provided on the furnace ceiling for about one and a half hours. carry out the fumigation process known of the street. Smoke treatment
After that, the combustion exhaust gas in the reducing atmosphere described later is sent to the heating furnace 1.
While being cooled down, it is cooled by natural cooling to around 300 ° C.
Be done.

A combustion chamber 11 composed of a small machine frame is attached to the outside of the heating furnace 1. The mounting structure can be any structure such as welding and detachable mounting with hooks. As shown in FIG. 2, a burner 12 is inserted into the combustion chamber 11 from the lower part, and a gas mixing pipe 13 is provided in the lower part of the combustion chamber 11 so as to communicate with the gas supply part of the burner 12.
3, a gas supply pipe 15 connected to a propane gas supply facility 14 (which may be a facility for gasifying petroleum) is connected via a solenoid valve 16, and an air supply pipe 18 connected to a blower 17 is also solenoid valve. It communicates via 19. A discharge electrode of an ignition transformer 20 by spark discharge is connected to the burner 12 by a discharge wire 21. The gas mixing pipe 13 is provided with a confirmation device 22 for confirming the ignition of the burner 12.

Reference numeral 24 is a control panel for the ignition transformer 20.
The operation command line 20a of No. 1 and the signal line 23 indicating whether or not the confirmation device 22 is ignited, the opening / closing command line (not shown) of the solenoid valves 16 and 19 are connected to open / close the solenoid valves 16 and 19 and the non-ignition of the confirmation device 22. The signal is used to control the driving of the ignition transformer 20 and the discharge electrode, etc. to ignite. A small amount of the combustion exhaust gas generated in the combustion chamber 11 is taken out and inspected by opening and closing the manual valve 26 provided at the analysis port 25. Reference numeral 27 denotes an exhaust gas feed pipe for feeding the exhaust gas generated in the combustion chamber 11 to the heating furnace 1. The exhaust gas contains H decomposed by the combustion.
_{Since the 2} O gas is mixed, when the pipe 27 comes into contact with the outside air and is cooled, the H ₂ O gas is condensed and forms a drain, which may hinder the flow of combustion exhaust gas. Shorten to avoid contact with. Combustion chamber 11
Is attached to the outside of the superheating furnace 1 in order to shorten the pipe 23.

According to the first aspect of the present invention, heating the roof tile material and
At the time of slow cooling after smoked, the combustion gas in the combustion chamber 11 is acidified.
Combustion exhaust gas in a reducing atmosphere generated by combustion in an element-deficient state
Gas is sent to the heating furnace 1 by the exhaust gas supply pipe 27.
Get caught As a result, the pressure inside the furnace becomes higher than the outside pressure.
Since it is retained, outside air containing oxidant enters the furnace.
Never. The component of this combustion exhaust gas is mainly N ₂ .
Yes, and also contains CO ₂ , H ₂ O, and CO.

According to the second aspect of the invention, as shown in FIGS. 3 to 5, a U-shaped radiant tube burner 3 is provided inside the heat treatment furnace 31.
In the present embodiment, 2 are provided by alternately changing the direction in 6 steps at equal intervals in the height direction, and both ends of each burner are opened to the outer surface of the furnace 31. Radiant tube burner 32 has one opening 32
The burner flame generated by burning with the burner provided in a
It has a well-known structure which has a function of passing through the shaped pipe and discharging from the other opening 32b. A lid (door) 33 is provided at the upper opening of the heat treatment furnace 31 so as to be hung by a crane and opened, or to close the opening. This lid (door) 33 has no special device for making the inside of the furnace airtight. Inside the heat treatment furnace 31, there are several seats 34 made of refractory installed on the lower frame.
Metal products (indicated by chain lines) and other metal products to be annealed , such as a coil having a large diameter, are placed as a set without using an antioxidant case as in the conventional case.

Outside the heat treatment furnace 31, a combustion chamber 11 composed of the same small frame as the combustion chamber 11 of the invention of claim 1 is attached, and the combustion chamber 11 has a burner 12 and a gas mixture equal to those in FIG.
Pipe 13, propane gas supply facility 14, gas supply pipe 1
5, solenoid valve 16, blower 17, air supply pipe 18,
An electromagnetic valve 19, an ignition transformer 20 connected to an operation command line 20a, a discharge line 21, a confirmation device 22, a signal line 23, and a control panel 24 are provided, and further, an analysis port 25, a manual valve 26, and exhaust gas generated in the combustion chamber 11 An exhaust gas feed pipe 27 for feeding the heat treatment furnace 31 is provided.

According to the invention of claim 2, the transmission interrupt only to heat treatment furnace 31 in exhaust gas generated in the combustion chamber 11,
Even when the heating of the furnace 31 is interrupted and the annealing is performed (the annealing may be performed while lowering the heating temperature by the radiant tube burner), the pressure outside the heat treatment furnace 31 is kept higher than the atmospheric pressure.
Replace the air with combustion exhaust gas in a reducing atmosphere. After that replacement
Is the reduction of the pressure inside the heat treatment furnace 31 that is higher than the outside pressure.
Since it is maintained in the atmosphere, the pressure difference causes outside air to enter.
do not do. Therefore, the metal products in the heating furnace should be oxidized.
There is no.

[0017]

The invention according to claim 1 of the present invention has the above-mentioned structure.
・ The function is to heat combustion exhaust gas in a reducing atmosphere
1 into the inside of the furnace due to cooling of the heating furnace
Since the pressure does not decrease, the ingress of outside air is blocked and the smoked roof tiles or
It is excellent in that it can prevent the oxidation of reduced reduction products.
effective.

The invention according to claim 2 has the above-described structure and operation.
However, the combustion exhaust gas in a reducing atmosphere is fed into the heat treatment furnace 31 before the heat treatment to replace the oxygen-containing outside air in the furnace with the exhaust gas, without using a large-sized oxidation prevention case as in the conventional case. There is an effect that metal treatment including cooling can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show an embodiment of the invention of claim 1 of the present invention, FIGS. 3 to 5 show an embodiment of the invention of claim 2, and FIG. 6 shows a radiant tube burner. It is an example of an antioxidant case that has been used in a heat treatment furnace.

FIG. 1 is a vertical sectional front view of a heating furnace 1.

FIG. 2 shows the arrangement of a small combustion chamber 11 and its surroundings.

FIG. 3 is a front view of a heat treatment furnace 31 that is heated by a radiant tube burner 32.

FIG. 4 is a plan view taken along the line AA in FIG.

FIG. 5 is an explanatory view of the arrangement of the heat treatment furnace 31 and the small combustion chamber 11.

FIG. 6 is a side view of an antioxidant case a.

[Explanation of symbols] 1 heating furnace, 2 multiple gas burners, 3 burner ports, 4 chimneys, 5 gas supply pipes,
11 combustion chamber, 12 burner, 13 gas mixing tube,
14 propane gas supply equipment, 15 gas supply pipe, 16 solenoid valve, 17 blower, 18 air supply pipe, 19 solenoid valve, 20 ignition transformer, 2
0a operation command line, 21 discharge line, 22 confirmation device,
23 signal lines, 24 control panel, 25 analysis port, 2
6 Manual valve, 27 Exhaust gas feeding pipe, 31 Heat treatment furnace, 32 Radiant tube burner, 32a
One opening, 32b Other opening, 33 Lid (door), 34 seat

Claims (2)

[Claims] 1. A method for baking roof tiles and smoldering black tiles in succession
A small combustion chamber is installed outside the heating furnace for smoked roof tile production.
Only the gas fuel or gasified fuel is supplied together with the combustion air to the combustion chamber, or combustion exhaust gas a reducing atmosphere generated by burning a mixture gas mixed with the combustion air by supplying oxygen insufficiency, tile dough During slow cooling after heating and smoking
Wherein by feeding in a heating furnace, than the outside atmospheric pressure the heating furnace
An in-furnace pressure holding device, which is configured to hold in a reducing atmosphere of high pressure . 2. A heat treatment furnace equipped with a radiant tube burner for heating is filled with a treated metal such as a coil, and a small combustion chamber is provided outside the heat treatment furnace. the gasified fuel is supplied together with the combustion air, or combustion exhaust gas a reducing atmosphere generated by burning a mixture gas mixed with the combustion air by supplying oxygen deficient state, the heat treatment furnace before the filling of the treated metal fed in, the pressure in the furnace holding apparatus characterized by being configured to hold a furnace to a reducing atmosphere of higher than the outside air pressure pressure.