JPS5912228A - Controlling method of furnace temperature of heating furnace and its device - Google Patents

Abstract

PURPOSE:To control and maintain a furnace temperature at a given value, by a method wherein a combined burner of each of a large and a small capacity burners is provided within a furnce, and when the furnace temperature exceeds the given value, only burning in a small capacity system is kept on and burning in a large capacity system is interrupted. CONSTITUTION:A large capacity burner 4 provided with an air feed pipe 2 and a fuel feed pipe 3 by interposing solenoids 10 and 11 in their midst respectively and a small capacity burner 7 provided with an air feed pipe 5 and a fuel feed pipe 6 are paired and installed in a heating furnace 1. Then, when a signal of a detected furnace temperature of the furnace 1 by a furnace temperature detector 8 becomes (furnace temperature-given temperature)>given value DELTAT (DELTAT>0) after comparison of the signal with the given temperature applied already to a furnace temperature controller 9 beforehand by keeping burning on, the burning at the burner 4 is suspended by shutting off valves 10 and 11 through the application of a solenoid valve controlling signal MVC from the controller 9. Only the burning at the burner 7 is kept on thereafter by the conroller 9 and air and fuel feed quantity controllers 12 and 20. With this construction, maintaining operation of the furnace temperature within a range of the given value can be performed precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a furnace temperature control method and apparatus for a heating furnace. More specifically, the present invention relates to a furnace temperature control method and apparatus for a heating furnace that burns the minimum amount of fuel without waste and maintains the inside of the furnace at a desired constant temperature.

-2- Conventionally, heating furnaces such as soaking furnaces and annealing furnaces are used to charge the objects to be heated and heat-treated. There are known types of heating furnaces that have a structure in which fuel is supplied for combustion and the furnace temperature is maintained at a predetermined temperature.In such heating furnaces, there are usually two combustion chambers in the same container depending on the capacity of the heating furnace. Multiple burners are installed in the furnace to burn fuel, and when the temperature inside the furnace reaches a predetermined temperature or higher, the fuel to these burners is
Furnace temperature control that reduces the air supply, shuts it off as necessary to extinguish the fire, and if the temperature drops below a predetermined temperature, increases or restarts the supply of fuel and air to ignite the furnace. has been carried out.

However, with this type of system, it is difficult to adjust the amount of each burner to the maximum amount of 115 or less due to the structure of the fuel supply control valve, etc., and if it is set to less than 115, combustion becomes extremely unstable. become. Therefore, the ratio between the maximum firing point and the minimum firing opening must be kept as small as 5:1, and since the furnace temperature fluctuates greatly due to burner control, it is necessary to keep it constant even within small fluctuations in furnace temperature. -3- It is difficult to precisely control the temperature, and there are disadvantages in that it leads to wasteful consumption of fuel. The present invention uses combustion equipment consisting of a combination of a large-capacity combustion burner and a small-capacity combustion burner to precisely control the temperature inside the furnace.
This eliminates the drawbacks of writing. That is, the first gist of the present invention is that in controlling the temperature inside the heating furnace, a combustion device consisting of a combination of a large-capacity burner and a small-capacity burner is installed in the furnace, Install more than that,
The amount of fuel and air supplied to each burner is adjusted by detecting the temperature inside the furnace and comparing it with a predetermined set temperature, and when the furnace temperature is outside the set temperature range, a small capacity A furnace temperature control method for a heating furnace comprises continuing the supply of fuel and air to the burner, while cutting off or continuing the supply of fuel and air to a large-capacity burner to perform combustion (heating), Furthermore, the second point is that in a heating furnace in which a combustion device consisting of a combination of a large-capacity burner and a small-capacity burner is installed in the furnace, the furnace temperature detected by the furnace temperature detector and the set temperature 1 input in advance are A furnace temperature controller that opens and closes a solenoid valve for controlling fuel supply to a large-capacity burner and a solenoid valve for controlling air supply based on the comparison result, and the furnace temperature control an air supply amount controller that controls the opening degree of a valve that adjusts the amount of air supplied to each burner while comparing the air supply amount to the air supply port to each burner based on the air supply amount setting value signal output from the device; and a valve that sets the amount of fuel supplied to each burner based on the amount of air supplied to each burner, and adjusts the amount of fuel supplied to each burner while comparing the amount of fuel supplied to each burner according to the set value. Installed a fuel supply amount controller that controls the opening degree.
This is in the furnace temperature control device of the heating furnace.

Hereinafter, the present invention will be explained based on the drawings.

The attached diagram shows a heating furnace system 1sI to which the control method of the present invention is applied.
FIG. 1 is a system diagram showing an example of a device.

In FIG. 1, 1 is a heating furnace, which includes a large-capacity burner 4 to which air for combustion is supplied through an air supply pipe 2 and fuel for combustion through a fuel supply pipe 3, and an air supply pipe 5. A small-capacity burner 7 to which air for combustion is supplied through a fuel supply pipe 6 and fuel for combustion is supplied through a fuel supply pipe 6 is installed in combination. Here, large capacity burner 4 and small capacity burner 7
A burner with a maximum fuel loading (supply) ratio of 3.5 to 5.5:1 is selected. The ratio of minimum firing rate (supply rate) and maximum firing rate (supply rate) for each burner itself is set to 1:5 due to the structure of the burner and the supply rate control valve described below. ing.

In this embodiment, an example is shown in which one set of a combination of a large capacity burner 4 and a small capacity burner 7 is installed.
Of course, the present invention can be applied even when a plurality of sets or combinations are used.

Inside the heating furnace 1, the furnace temperature due to combustion of fuel in a large capacity burner 4 and a small capacity burner 7 is detected.

For example, a furnace temperature detector 8 such as a thermocouple is provided,
The detection signal is transmitted to the furnace temperature controller 9.

The furnace m! The temperature inside the furnace that should be kept constant is input in advance to the II fill device 9 as a set temperature, and the set temperature is compared with the detected temperature detected by the furnace temperature detector 8, and based on the comparison result, It outputs the solenoid valve control I@MMC, which is the furnace temperature control signal-6-, and the air supply amount set value signal MVA. The solenoid valve control signal MMC controls the opening and closing of solenoid valves 10 and 11, which are provided in the air supply pipe 2 and fuel supply pipe 3 to the large-capacity burner 4, respectively, and function to supply or cut off air and fuel. conduct. In addition, the air supply amount set value signal @MVA is a signal indicating the air supply amount setting value of each of the air supply amount controller 12 of the large capacity burner 4 and the air supply amount controller 13 of the small capacity burner 7. and the controller 12
Now, compare this air supply amount set value signal @MVA with the air supply amount detected by the air flow cutout 14 provided in the air supply piping 2 to the large capacity burner 4, and from the comparison result, the air supply control signal Mv1 Output. The air supply amount control signal MV1 is controlled by the value of the air supply amount set value signal MVA in the large capacity burner 4 and the air flow provided in the air supply piping 5 to the small capacity burner 7 so as to match the air supply amount set value. 7- Compare the air supply amount detected by the air supply 5a and output the air supply amount control signal MV2 based on the comparison result. The air supply m control signal M V 2 controls the opening amount of the air supply amount adjusting valve 16 installed in the air supply piping 5 to the small capacity burner 7 so as to match the set value of the air supply amount. . 17 is a controller for the amount of fuel supplied to the large capacity burner 4, and an air supply pipe 2 to the large capacity burner 4;
A value corresponding to the air supply amount detected by the air flow meter 14 provided in the large capacity burner 4 is input as the fuel supply setting value to the large capacity burner 4. Then, in the controller 17, the fuel supply setting value is set to the fuel supply pipe 3 to the burner 4.
It is compared with the fuel supply amount detected by the fuel flow cutout 18 provided in the fuel flow cutout 18, and based on the comparison result, a fuel supply amount control signal MVa is output. The fuel supply amount control signal MVa is applied to the large capacity burner 4 in order to match the fuel supply setting value.
A fuel supply amount control valve 19 installed in the fuel supply pipe 3 to
Controls the opening amount of the valve. Further, 20 is a controller for the supply amount of fuel supplied to the small capacity burner 7, and the air supply amount detected by the air flow meter 58 provided in the air supply pipe 5 to the small capacity burner 7 is controlled. It is input as the fuel supply amount setting value to the small capacity burner 7.

Then, the controller 20 compares the fuel supply setting value with the fuel supply amount detected by the fuel flow needle 68 provided in the fuel supply pipe 6 to the small capacity burner 7, and based on the comparison result. , outputs a fuel supply amount control signal MVa.

The fuel supply amount control signal MVa is the fuel supply amount control signal MVa. ! The opening amount of the fuel supply amount control valve 21 provided in the fuel supply pipe 6 to the small capacity burner 7 is controlled so as to match the set value of one supply amount.

In the above-described operation, for example, if the furnace temperature in the heating furnace 1 is detected by the furnace temperature detector 8 and the value exceeds the set temperature range inputted in advance to the furnace temperature controller 9,
That is, when (furnace temperature - set temperature)>predetermined value ΔT (ΔT>0) is reached, the solenoid valve control signal MVC is output from the furnace temperature controller 9, the solenoid valves 10 and 11 are closed, and the large capacity burner is 4
After that, combustion of fuel is interrupted in the small capacity burner 7 by the furnace temperature controller 9, controllers-9-13, and 20, and the furnace temperature is precisely maintained within the set temperature range. It will be held on. Conversely, if the combustion in the large-capacity burner 4 is interrupted and the furnace temperature drops and becomes (furnace temperature - set temperature) ≦ predetermined temperature ΔT, the furnace temperature detector 8 detects this. The solenoid valve 10.11 is opened by the control signal MMC based on the comparison result sent to the till control device 9 by the signal MMC, and the combustion in the large-capacity burner 4 is restarted, and the above-mentioned control continues repeatedly. The furnace temperature is maintained within a preset temperature range. As described above, the present invention relates to a control method and device for maintaining the furnace temperature in a heating furnace within a preset range, and compared to conventionally known heating furnaces, It has the following advantages and has great industrial utility value.

(1) Since the combustion equipment is equipped with a combination of large-capacity burners and small-capacity burners, there are no gaps in the flow of fuel in the furnace (
For example, as shown in Figure 2, the maximum loading of a large-capacity barb and the maximum firing capacity of a small-capacity burner can be made large. When the ratio is set to 4.5:1, the firing ratio when the two burners are maximized and when only the small-capacity barb is burned at the minimum firing ratio is 27.5:1, which provides a wide range of combustion. It is possible to adjust the dosage over a period of time.

(2) Even if the amount of iron required for the fuel in the heating furnace varies significantly, the desired furnace temperature can be maintained without turning off the combustion equipment.

(3) Even if the furnace temperature exceeds the set temperature and the operation of the large-capacity burner is interrupted, combustion control of only the small-capacity burner continues, making it possible to sharply adjust and control the furnace temperature. Temperature control is possible and there is no fluctuation in furnace temperature.
Wasteful consumption of fuel is reduced, resulting in energy saving effects.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a control system of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the firing of a burner. 1...Heating furnace-11- 2,5...Air supply piping 3.6...Fuel supply piping 4...Large capacity burner 7...Small capacity burner 8...Furnace temperature detector 9 ...Reactor control device 10.11...Solenoid valve 12.13...Air supply amount controller 14...Air flow meter 15.16...Air supply amount adjustment valve 17.20... Fuel supply amount controller 18...Fuel flow rate 81 19.21...Fuel supply control valve agent Patent attorney Tsutomu Seiri-12-

Claims (1)

[Claims] 1. In order to control the temperature inside the heating furnace, one or more combustion devices consisting of a combination of a large capacity burner and a small capacity burner are installed in the furnace. , the amount of fuel and air supplied to each burner is adjusted while detecting the temperature inside the furnace and comparing it with a predetermined set temperature, and when the furnace temperature is higher than the set temperature range, the small capacity 1. A furnace temperature control method for a heating furnace, characterized in that the supply of fuel and air to a large-capacity burner is continued, while the supply of fuel and air to a large-capacity burner is reduced to carry out combustion. 2. The furnace temperature control method for a heating furnace according to claim 1, wherein the maximum fuel combustion ratio between the large-capacity burner and the small-capacity burner is in the range of 3.5 to 5.5:1. 3 In a heating furnace in which a combustion device consisting of a combination of a large-capacity burner and a small-capacity burner is installed -1-, a comparison is made between the furnace temperature detected by the furnace temperature detector and the preset temperature input. and a furnace temperature controller that opens and closes the '11m valve for controlling fuel supply to the large-capacity burner and the solenoid valve for controlling air supply based on the comparison results, and the air output from the furnace temperature suppressor. An air supply amount controller that controls the opening degree of a valve that adjusts the amount of air supplied to each burner while comparing the amount of air supplied to each burner based on a supply amount set value signal, and an air supply amount controller that controls the opening degree of a valve that adjusts the amount of air supplied to each burner, and Set the fuel supply amount to each burner based on the supply amount, compare the fuel supply amount of each burner according to the set value, and teach the opening degree of the valve that adjusts the fuel supply amount to each burner. A furnace temperature control device for a heating furnace, which is equipped with a fuel supply amount till 1m11.