JPS5858238A - Soaking pit - Google Patents

Abstract

PURPOSE:To make the temp. in a furnace uniform and to reduce the fundamental unit of fuel by providing plural suction ports for waste gases in the bottom part of a soaking pit of one-way firing in the upper part provided with a burner device in the upper part on the side wall of the furnace. CONSTITUTION:The waste gases of combustion discharged from a burner 3 provided in the upper part on the side wall 2 of a soaking pit 1 flow in the furnace as shown by solid arrows, turn over from the position of approximately half the furnace length and are sucked into plural pieces of the 1st suction ports 4 for waste gases provided in the hearth. These gases flow through the ports 4 then through a gas conduit 5 into a flue 6. If the 2nd suction port 7 for waste gases is provided below the burner 3, part of the combustion gases are discharged through the port 7 then through the flue 6 according to the degree of opening or closing of a damper device 8. Then the inside of the furnace 1 is heated uniformly, the heating time is reduced and the fundamental unit of fuel is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soaking furnace, and particularly to an upper one-way firing soaking furnace which aims to equalize the temperature inside the furnace.

A soaking furnace is a furnace used to uniformly heat a lump, plume, billet, slab, or other steel material to a predetermined temperature prior to blooming or hot rolling.There are several heating methods. The most common type is the so-called top one-way firing type, which heats by burning a burner installed at the top of the f* wall.

By the way, the gas flow inside the furnace of such an upper unidirectional firing soaking furnace has a unique U-shaped flow, so the upper part on the side opposite to the burner has the highest temperature, and the lower part on the burner side has the highest temperature. becomes lower. In other words, since it is an upper one-way firing soaking furnace,
The gas inside the furnace flows from the burner outlet along the wall opposite to the burner, reverses, passes through the lower part of the opposite side of the burner, passes through the flue from the exhaust gas inlet at the lower part of the burner side, and is exhausted to the atmosphere. Ru.

Therefore, the temperature in the lower part of the burner side is the lowest in the furnace because the gas from which heat has been released on the side opposite to the burner is already flowing.

By the way, in the past, soaking furnaces mainly heated steel ingots, but as continuous casting progresses, existing soaking furnaces can be effectively utilized to soak plumes or slabs after continuous casting. Heating in a furnace became widely used. Therefore, in current soaking furnaces, rather than steel ingots as the material to be heated, plumes or slabs are stacked in multiple stages and charged into the furnace for heating, which results in a particularly large temperature difference within the soaking furnace. Therefore, the 4-hour period of the one-way soaking furnace as mentioned above, together with the occurrence of spreading inside the furnace due to its structural conformation, makes it difficult to maintain the uniformity of the charged and heated material as its original function. Heating is becoming difficult.

Conventional countermeasures have been to change the charging format of the bloom or slab in order to smooth the flow of hot gas inside the furnace, or to install an auxiliary burner near the exhaust gas inlet. Yes, but it is not a drastic measure. For example, for equipment where the temperature near the lower part of the burner side is particularly low, there is a method of forcibly eliminating the problem by installing an auxiliary burner from the existing exhaust gas suction port (see % Japanese Patent Publication No. 41816/1983).

Another method for reducing the temperature difference inside the soaking furnace is to detect the temperature on the burner side and the temperature on the side opposite to the burner, and change the length of the flame emitted from the burner based on the temperature difference. 678454).

Furthermore, the combustion exhaust gas is forced to circulate near the burner,
Various proposals have been considered to solve the problem, such as increasing the temperature at the lower part of the burner side, but these only make the structure and operation of the furnace unnecessarily complicated, and are of little practical value.

Therefore, in order to raise the temperature at the bottom of the burner side, the diopter setting inside the furnace has been increased or the heating time has been increased, which has resulted in a high fuel consumption rate and a high temperature inside the furnace. A decrease in the life of the furnace body was observed.

Thus, an object of the present invention is to greatly improve the flow of combustion exhaust gas in the furnace and increase the temperature at the bottom of the burner side, thereby eliminating the need to raise the set temperature in the furnace as in the past. ,
Moreover, it is an object of the present invention to provide a unidirectional firing soaking furnace which can shorten the heating time and thereby greatly reduce the fuel consumption rate.

Herein, the present invention provides: (1) In an upper one-way soaking furnace having a burner device provided at the upper part of the furnace side wall, the upper one-way heating furnace is characterized in that one or more exhaust gas suction ports are provided at the bottom of the furnace. A firing soaking furnace, and (2) an upper one-way firing soaking furnace in which a burner device is provided on the upper part of the furnace side wall, in which one or more exhaust gas inlet suction ports are provided at the bottom of the furnace, and This is an upper one-way firing soaking furnace which is equipped with an upper second exhaust gas suction port provided with a damper device at a position below the burner device.

Thus, according to the present invention, the flow of combustion gas in the furnace proceeds straight from the burner discharge port, reverses itself at about 50% of the furnace length, and is discharged from the exhaust gas suction port provided in the hearth. Ru. Therefore, the temperature in the lower part of the burner side, which was particularly underheated, is greatly improved, and the fuel consumption rate can be reduced by shortening the heating time.

Furthermore, by adjusting the damper device of the second exhaust gas suction port provided below the burner device, the flow of combustion gas in the furnace can be freely controlled.

By the way, in existing soaking furnaces, an outlet for bricks, etc. after repair, that is, a cinder hole is already provided in the hearth, so when implementing the present invention in such an existing soaking furnace, such Use a cinder hole as an inlet for combustion exhaust gas, connect it to the existing flue, and at the same time block the conventional exhaust gas inlet located below the burner side with a brick, etc.
Alternatively, it is sufficient to simply attach a damper device to it. The number and position of exhaust gas suction ports provided in the hearth are appropriately determined depending on the dimensions, capacity, and set heating temperature of the furnace. Preferably, the furnace dimensions for example 150 T/ah are 4100 mm wide.
In a soaking furnace with an algae of 4550 cm and a length of 7700 cm, the temperature inside the furnace is set at 1280°C, 06- is placed on the hearth.
(T! From the A burner side) It can be installed at a depth of 2 m.

The invention will now be further described in connection with the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of a soaking furnace l according to the present invention. In the illustrated example, the combustion gas discharged from the burner device 3 provided on the furnace side wall 2 is as shown by the solid arrow in the figure. The flow inside the furnace is reversed from the half-way position of the furnace length, and is sucked into a plurality of exhaust gas suction ports 4 provided in the hearth, and reaches the flue 6 via the exhaust gas conduit 5.

When a second exhaust gas suction V↑ lower is provided below the burner device, a portion of the combustion gas is discharged from the second exhaust gas suction lower through the flue 6 depending on the degree of opening and closing of the damper device 18.

According to the present invention, the combustion gas from the burner unit (18) is not reversed and returned from the opposite burner wall 2', but the combustion gas from the furnace head is
Since it reverses from about 50%, sufficient heat can be retained even when reaching the second exhaust gas suction lower, for example, so that the vicinity thereof can be sufficiently heated.

Similarly, the vicinity of the first exhaust gas inlet provided in the hearth is also sufficiently heated. In the figure, dotted arrows indicate the flow of combustion gas when no exhaust gas suction port is provided in the hearth, as seen in the conventional apparatus. The combustion gases from the burner device hit the anti-burner wall and are reversed to align with the exhaust gas inlet.

Therefore, by opening 11LA1iB of the damper device ft (provided at the conventional exhaust gas inlet at the lower part of the burner side), the flow of the combustion exhaust gas in the furnace is adjusted C'JM. Therefore,
By detecting the burner-side OA degree and the opposite-burner side temperature and adjusting the damper opening degree based on this temperature difference, the gas flow can be changed, thereby eliminating any temperature difference in the soaking furnace. As mentioned above, applying the present invention to an existing furnace is advantageous because existing equipment can be used; Exhaust gas is extracted from this location by using a part of the cinder hole already installed in the soaking hearth, and it is then transferred to the conventional downtake section. It may also be connected to a viewing window (sight hole) to serve as a combustion exhaust gas conduit. Furthermore,
A damper device is provided at the exhaust gas suction port in the lower part of the conventional burner side, and the flow of the combustion exhaust gas discharged from the cinder hole can be adjusted by this damper device.

Next, a specific example of applying the present invention to an existing furnace will be described.

The cinder hole installed in the hearth of the soaking furnace 1 is used as the first exhaust gas suction port 4, and the site hole in the flue 6 is connected with the flue gas conduit 5 4: the second exhaust gas suction port 7: the second exhaust gas suction port Exhaust gas inlet 5: Exhaust gas conduit 8
: Damba device 6: Flue applicant's attorney]:

Claims (2)

[Claims] (1) An upper one-way firing soaking furnace in which a burner device is provided at the upper part of the furnace 44 wall, and one or more exhaust gas suction ports are provided at the bottom of the furnace. (2) In an upper unidirectional firing soaking furnace in which a burner device is provided at the upper part of the furnace side wall, one or more exhaust gas suction ports are provided at the bottom of the furnace, and at a position below the burner device on the wall of the furnace, An upper one-way firing soaking furnace characterized by having second exhaust gas e and A ports fitted with a damper device.