JPS6384748A - Drying apparatus for tundish - Google Patents

Abstract

PURPOSE:To execute the temp. rising of a tundish with high accuracy by setting opening degree of air control valve to plural conditions in a gas burner type drying apparatus and also arranging control means adjusting a gas control valve based on the detected result of temp. CONSTITUTION:In plural gas burners 20 arranged in the tundish, the LPC gas from branch pipes 22 connected to a main gas pipe 21 and the compressed air from branch pipes 27 connected to a main air pipe 26 are supplied. At the time of firing to a pilot burner 31 by a pilot torch 39, the program setter sets a valve 28 to a first opening degree I by a motor 29 and at the same time, a solenoid valve 30 is opened, to start firing of the burner 20. Each control device controls the opening degree of valve 23 by a motor 24 at PID, so that the detected value of combustion temp. by thermocouple 40 coincides with the temp. rising curves A, B as the control aim. This working is continued till the operation based on the aimed temp. rising curves E, F, finishes. In this way, the temp. rising of tundish is controlled under high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drying device for a tundish used in a continuous casting machine, and is capable of raising the temperature of a tundish along a predetermined temperature increase curve with high precision. Regarding the heating device for Tanditshu.

[Prior Art] Traditionally, the tanditshu of a continuous casting machine is constructed using shaped bricks. However, recently, in order to reduce the unit consumption of refractories, a technique has been proposed in which the inner work bricks of the tandish are constructed using poured material instead of regular bricks. This pouring material is a cementless castable mainly composed of approximately 60% Al2O3 and contains 5 to 8% water. This pouring material is
After being molded onto the inner surface of the tundish by pouring it into a mold, it is dried. In this drying process, in order to prevent the pouring material from exploding, the temperature of the pouring material is increased at a rate of 100.degree. C./hour or less to approximately 800.degree. C. in terms of Rn.

FIG. 4 is a plan view showing a conventional tundish drying apparatus, and FIG. 5 is a diagram of its gas piping.

Four gas burners 2.
3.4.5 are spaced apart from each other. Four gas branch pipes 7 are branched from a main gas pipe 6 connected to a supply source such as coke oven gas (COG). This gas branch pipe 7
Each burner 2°3.4.5 is connected to the tip of the burner. The air main pipe 8 connected to a compressed air supply source such as a proa
Similarly, four air branch pipes 9 are connected, the tips of which are also connected to burners 2.3.4.5.

At each burner 2.3, 4.5, C from the gas branch 7
OG and compressed air from the air branch pipe 9 are mixed, and this mixed gas is combusted.

A pilot burner 10 is arranged near each burner 2.3.4.5, and an auxiliary pipe 11 is connected to this pilot burner 10, and the auxiliary pipe 11 is connected to the main gas pipe 6. A gas auxiliary pipe 12 and an air auxiliary pipe 13 connected to the main air pipe 8 are connected. Therefore,
A mixed gas of COG and air is supplied to the auxiliary pipe 11 via a gas auxiliary pipe 12 and an air auxiliary pipe 13, and this mixed gas is burned in the pilot burner 10. This pilot burner 10 is always burning, and each burner 2, 3
, 4, and 5 are ignited.

A control butterfly valve 14 for controlling the amount of air supplied is installed in the main air pipe 8, and a manual butterfly valve 15 is installed in each air branch pipe 9. On the other hand, each gas branch pipe 7 is provided with a regulator 16, and each regulator 16 adjusts the amount of COG flowing through the gas branch pipe 7 according to the amount of air flowing through the air branch pipe 9 (air-fuel ratio control). ).

As shown in FIG. 4, the temperature of the inner wall of the tundish 1 is detected by a thermocouple 17 placed in the center of the tundish 1, and the amount of mixed gas supplied to the burner is adjusted. The temperature of the inner wall of the tundish is raised along the temperature rise curve to dry the poured material.

[Problems to be Solved by the Invention] However, this conventional drying device has the following drawbacks. First, since the responsiveness of the regulator 16 is poor, the temperature control accuracy is low, and there is a temperature variation of ±50° C. with respect to the predetermined temperature shown by the temperature rise curve in FIG. Also,
Since a regulator is used, for each burner,
In addition to not being able to control combustion using different temperature patterns, it is also not possible to stop combustion in some burners.

Therefore, drying cannot be carried out under optimal conditions depending on the shape or size of the tundish (one-strand tundish).

The present invention has been made in view of the above circumstances, and provides a tanditsu drying device that can control the temperature with high precision along a preset drying curve without requiring expensive equipment. The purpose is to

[Means for Solving the Problems] A tanditsu drying device according to the present invention includes a plurality of burners, a gas main pipe connected to a gas supply source, a gas branch pipe connecting each burner and the gas main pipe, A plurality of gas control valves installed in each gas branch pipe, an air main pipe connected to a compressed air supply source, an air branch pipe connecting each burner to the air main pipe, and an air control installed in the air main pipe. a valve, a thermometer that measures the combustion temperature of each burner, and a control means that sequentially switches the opening degree of the air control valve to a plurality of IT% and adjusts the opening degree of the gas control valve based on the detection result of the thermometer. It is characterized by having the following.

[Operation] In the present invention, the amount of gas such as COG is adjusted by the control means based on the combustion temperature detected by the thermometer. On the other hand, the amount of air is switched in stages with a plurality of flow rates, and the amount of air is constant at each stage. Therefore, in each stage, the combustion temperature is increased in the first half with an excessive amount of air, and in the second half, the air m and gas volume are adjusted to the optimum combustion efficiency ratio (for example, air-fuel ratio 1.4).
) and burn it. In this invention, combustion 'a
r! Since the drying temperature is measured and the gas temperature is adjusted based on the measurement results, the drying temperature can be controlled with high precision.

Since each burner is provided with a gas control valve, the combustion temperature of each burner can be controlled and drying can be performed under optimal conditions depending on the shape or size of the tundish. In this invention, combustion is performed in a state where there is an excess of air rather than air-fuel ratio control. Therefore, there is no need to adjust the air volume and gas volume itself with high precision, so inexpensive butterfly valves etc. can be used.
Equipment costs are low.

[Embodiment] FIG. 1 is a schematic diagram of a drying apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram thereof. This drying device is
It has four burners 20 (only one burner is shown) spaced apart by an appropriate length in accordance with the shape of the tundish. Four gas branch pipes 22 are connected to a main gas pipe 21 connected to a supply source of low pressure coke oven gas (LPG).
Each gas branch 22 is connected to a burner 20 . Therefore, LPG is supplied to the burner 20 via the gas main pipe 21 and the gas branch pipe 22. The blower 25 has an air main pipe 26
is connected to the main air pipe 26, and four air branch pipes 27 are connected to the main air pipe 26.

Each air branch pipe 27 is connected to a burner 20, and LPG from the gas branch pipe 22 and compressed air from the air branch pipe 27 are mixed and burned in the burner 20.

A control butterfly valve 23 is interposed in each gas branch pipe 22 . The opening and closing of this valve 23 is driven by a motor 24. Further, this gas branch pipe 22 includes a solenoid valve 30.
It is also interposed. This solenoid valve 30 shuts off the gas branch pipe 22 when the burner 20 goes out.

A control butterfly valve 28 is interposed in the main air pipe 26 , and this valve 28 is driven to open and close by a motor 29 .

A pilot burner 31 is arranged near each burner 20. A mixed gas supply pipe 34 is connected to this pilot burner 31, and a pilot burner gas branch pipe 33 and a pilot burner air branch pipe 37 are connected to this supply pipe 34. Each gas branch pipe 33 is connected to the gas main pipe 21 via a pilot burner gas main pipe 32. Further, a barlot burner air main pipe 36 is connected to the air main pipe 26, and four pilot burner air branch pipes 37 are branched from this air main pipe 36.

LPC and air from the gas branch pipe 33 and the air branch pipe 37 are supplied to the pilot burner 31 via the mixed gas supply pipe 34. Note that a solenoid valve 35 is installed in the main gas pipe 33, so that when the pilot burner 31 goes out,
This solenoid valve 35 shuts off the gas branch pipe 33.

A pilot torch 39 is connected to the main gas pipe 21 via a flexible gas pipe 38. This pilot torch 3
9 is always ignited and is used to ignite the mixed gas of LPG and air ejected from the pilot burner 31.

A thermocouple 40 is arranged near each burner 20, and as shown in FIG. 2, this thermocouple 40 detects the combustion temperature of the burner 2o and outputs the detection result to a controller 42. . A control target value is inputted to each controller 42 from the program setting device 41, and each controller 42 drives the motor 24 so that the temperature measurement value matches the control target value.
Adjust the opening degree of the control valve 23. The program setting device 41 drives the motor 29 to adjust the opening degree of the control valve 28 disposed in the main air pipe 26, for example, in three stages.

Next, the operation of the drying apparatus configured as described above will be explained with reference to the temperature rise curve shown in FIG.

With the solenoid valve 35 open, the pilot burner 31 is ignited by the pilot torch 39.

Next, the program setter 41 adjusts the motor 29 to set the opening degree of the valve 28 to the first opening degree (I), and at the same time,
The solenoid valve 30 is opened and the control target value of the controller 42 is changed along the temperature rise curves shown in A and B in FIG. Then, based on the detection result of the thermocouple 40, the controller 42 controls the opening degree of the valve 23 via the motor 24 so that the detected temperature matches the control target value. II control. In this case, during period A, combustion occurs with excess air, and during period B, combustion occurs with the ratio of air to LPC close to the air-fuel ratio of 1.4.

In this way, at a temperature of about 200°C, about 1
When 8 hours have elapsed, the setting device 41 sets the opening degree of the valve 28 to the second opening fil (II), and changes the control target value of the controller 42 along lines C and D in FIG. . Controller 4
2 controls the opening degree of the valve 23 based on this target value.

Then, after about 30 hours have passed after the start of drying, valve 2
8 is set to the third opening degree (I [I), and the opening degree of the valve 23 is set so that the temperature detected by the thermocouple 40 is the temperature rise curve E and F in FIG.
Opening/closing control is performed so that the opening/closing changes along the

Then, the material is heated to about 600.degree. C., and after about 42 hours have elapsed from the start of drying, all the electromagnetic valves 30 are turned on to complete the drying. Note that the control target value (drying curve) that this program setting device 41 sets in each controller 42 is different for each burner 20 depending on the shape of the tundish, etc., and combustion is controlled independently for each burner. Also good. Also, by drying with a specific solenoid valve 30 closed,
When the size of the tundish is short, combustion of the burner at a position away from the tundish can be stopped.

According to the drying device configured in this way, combustion ma can be controlled with high precision to within ±1° C. with respect to the set temperature. Further, since the flow rates of gas and air themselves do not need to be adjusted with high precision, they can be adjusted using inexpensive valves such as butterfly valves, without using expensive valves such as diaphragm valves. Therefore, this drying device is low cost.

[Effects of the Invention] According to the present invention, the combustion temperature can be controlled with high accuracy along a predetermined temperature increase curve, although the equipment cost is low. Further, combustion can be controlled independently for each burner.

[Brief explanation of the drawing]

4 is a plan view showing a conventional drying device, FIG. 5 is a piping diagram thereof, and the sixth factor is a diagram showing a temperature rising curve.

Claims (3)

[Claims] (1) A plurality of burners, a gas main pipe connected to a gas supply source, and a gas branch pipe connecting each burner and the gas main pipe,
A plurality of gas control valves installed in each gas branch pipe, an air main pipe connected to a compressed air supply source, an air branch pipe connecting each burner to the air main pipe, and an air control installed in the air main pipe. a valve, a thermometer that measures the combustion temperature of each burner, and a control means that sequentially switches the opening degree of the air control valve to a plurality of modes and adjusts the opening degree of the gas control valve based on the detection result of the thermometer; A tundish drying device characterized by having: (2) Each burner is equipped with a pilot burner, an air pipe that supplies air to the pilot burner, and a gas pipe that supplies gas to the pilot burner, and the burner is ignited by combustion in the pilot burner. The tundish drying apparatus according to claim 1, wherein the tundish drying apparatus is characterized in that: (3) A claim characterized in that each gas branch pipe and gas pipe is provided with a solenoid valve, and when the burner or pilot burner stops burning, the solenoid valve provided in the gas branch pipe or gas pipe is closed. The tundish drying device according to item 1.