JPS5826404B2 - Furnace temperature control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a furnace temperature control start procedure for a heating furnace.

In recent years, control computers have been increasingly used to control the furnace temperature of heating furnaces from the viewpoint of energy conservation.

Computer-based furnace temperature control detects the position and temperature of each material in the furnace, predicts how long each material will pass through each furnace zone and be extracted from the furnace, and then controls each material according to the schedule. Methods are used to optimally control the temperature of the furnace zone.

Therefore, the conditions for controlling the furnace temperature using a computer are as follows:
The computer needs to know the location, temperature, and specifications of all the materials in the heating furnace.

Now, when talking about temperature control of a heating furnace, there are generally the following three
It consists of two devices.

■ An in-furnace tracking device that memorizes the specifications of the material when it is charged into the heating furnace, and thereafter updates and stores the position of the material as it moves within the furnace.

■ A temperature calculation device for the material in the heating furnace that calculates the temperature of the material based on changes in furnace temperature and the passage of time after the material is charged into the heating furnace.

■ Based on the specifications of each material in the furnace stored by the furnace tracking device in ■, the position of the material, and the temperature of each material calculated by the temperature calculation device in This is a furnace temperature control device that calculates the optimal way to control the temperature of the furnace zone.

Now, a problem with furnace temperature control consisting of the above three devices is when the furnace tracking using a computer or the material temperature calculation device does not match the actual material.

For example, even if the computer controlling the furnace temperature goes down, the movement of materials within the furnace and the furnace temperature control are usually performed manually.

Therefore, in this case, the computer's information on the position of the material in the furnace and the temperature information on the material in the furnace will no longer match the actual information when the computer returns to normal.
In many cases, it becomes impossible to start furnace temperature control using the J machine.

Therefore, furnace temperature control start processing is required.

Conventionally, the following two methods have been used for furnace temperature control glue start processing.

The first is that when the computer returns to normal, the on-site operator inputs the positions and temperatures of all materials in the furnace into the computer.
The second method is to restart the furnace temperature control after matching the position and temperature of the computer and the actual material.The second method is to give up on controlling the furnace temperature using the computer of the actual material in the heating furnace once the computer returns to normal. , when the actual material that was charged into the heating furnace after the computer returned to normality came to the extraction side of the heating furnace, that is, all the materials that were in the furnace at the time the computer returned to normality were removed from the heating furnace. This type of conventional glue start is a restart method in which the operator resumes furnace temperature control from the point at which the only material left in the furnace is the material whose location and temperature are stored in the computer's memory. Problems with this method include the following.

First, for the former, there are too many items that the operator must input into the computer, and it is difficult for the operator to remember the exact location of the material in the furnace, so it is difficult to input the operator's input into the computer. The values themselves tend to be inaccurate.

The problem with the latter glue start method is that the timing at which the computer starts controlling the furnace temperature is delayed, and the operator has to manually control the furnace temperature for a while even after the computer returns to normal.

An object of the present invention is to simplify furnace temperature control restart processing when the computer is restarted midway through using a computer, reduce input items to the computer by the operator, and reduce the number of input items to the computer as much as possible. The object of the present invention is to provide a method for quickly returning to computer-based control of the furnace temperature.

In the heating furnace temperature control restart process of the present invention, the material stored in the computer and the actual material are matched as much as possible at the time of restart performed by the operator.

In order to simplify the matching process and to perform furnace temperature control using a computer as quickly as possible, the furnace temperature control is restarted based on the following principle.

■ When the computer itself is restarted, the furnace temperature control for the material in the heating furnace is set to 1 manually.

■ After restarting the computer, restart the furnace temperature control using the computer for each furnace zone, which is the unit of furnace temperature control.

■ The start timing of furnace temperature control by the computer in each furnace zone is based on the first material charged into the heating furnace after the computer restarts.The first material whose position and temperature are recognized by the computer is As soon as the belt passes a certain point,
Computer-based furnace temperature control is restarted for each furnace zone.

By the above method, it is possible to automatically start the furnace temperature control using the heating furnace computer, and it is also possible to simplify the process of inputting information into the computer by the operator in order to start the furnace temperature control.

An embodiment of the invention is shown in FIG.

1 in Fig. 1 is a heating furnace, and the furnace temperature is controlled by dividing it into a pre-heating zone, a heating zone, and a soaking zone.

4. 5. 6. 7°8 is the material to be heated.

1o is a charging device that charges the material to be heated 4 into the heating furnace from the heating furnace charging port 2.

The material to be heated charged by 1o is moved by an in-furnace material moving device such as a walking beam 12, and is heated and soaked while being conveyed to the heating furnace extraction port 3.

11 is a pulse generator attached to the charging device 1o and the material moving device 12, and the pulses generated by 11 that detect the respective movement amounts as pulses are sent to the in-furnace tracking device 13. is input.

The in-furnace tracking device 13 captures the number of pulses from the pulse generator 11 attached to 10 when the material to be heated 4 is charged into the heating furnace, and detects the number of pulses when the material to be heated 4 is initially charged into the furnace. 2. Recognize the distance from the heating furnace charging port at the time when the

Thereafter, each time the in-furnace material moving device 12 moves, the number of movement pulses is taken from the 11 pulse generators attached to 12,
The distances of all the materials to be heated 5 to 8 in the heating furnace 1 from the heating furnace charging port are calculated and tracked.

18 periodically takes in the actual furnace temperature from the thermometer installed in the furnace in 9 and the position of the material to be heated in the furnace from the tracking device in 13, and calculates the material temperature 18a of the material to be heated in the heating furnace. This is a material temperature calculation device.

19 takes in the material temperature of the material to be heated in the furnace from 18 and 13, respectively, and the heating specification of the material to be heated from the material specification storage device of material position signal 13a and 22, and calculates the temperature of the material from the temporal change in the material position. This is a furnace temperature calculation device that predicts how long it will be in the furnace zone and calculates the furnace temperature target value 19a, which is the temperature at which each furnace zone should be set, based on the heating specifications of the material to be heated and the current material temperature. .

Now, when the furnace temperature control systems 13, 18, and 19 temporarily go down and recover, restart, which is a switching process between manual and automatic furnace temperature control, is performed in the following procedure.

When the furnace temperature control system recovers from DOWN, the material position information of the heated material recognized by the furnace tracking device 13 and the actual material position do not match, and the material temperature calculation device 18 Since the temperature change of the material while the furnace temperature control system is down is not calculated, the temperature of the material to be heated that 18 recognizes does not match the actual temperature of the material.

Therefore, it is impossible to determine the furnace temperature target value 19a using 19.

Therefore, furnace temperature control start processing is required.

The procedure for automatically turning on furnace temperature control during restart is as follows.

14 is a restart signal 14-□ to 14-3 generating device, which outputs the position of the heated material from 13 and the control system normal signal 1.
Enter 3b.

The control system normal signal may be a computer normal signal if, for example, the tracking device 13 is operated by a computer.

The restart signal generating device No. 14 generates a control system normal signal OF
When F, outputs OFF.

Furthermore, after the control system normal signal turns ON, input the material position of the material to be heated 7 that was first charged into the heating furnace 1, and
Each time the material position passes the extraction port side of each furnace zone, the OK signal (furnace temperature control lister) of each furnace zone is turned ON.

15 is automatic setting by the operator of the heating furnace control system;
This is a manual switching SW, and if the control system is automatic, it outputs ON.

15 automatic manual switching SW signal and 14 Lister) O
The K signal is ANDed for each furnace zone using 16 AND devices.
When both signals of each furnace zone are ON, an ON signal is generated.

17-117-2.17-3 is an automatic manual switching device for controlling the furnace temperature of each furnace zone, and the furnace temperature target value of each furnace zone of 19,
0□, 20-2. It is a device for manually switching the furnace temperature set value of each furnace zone of 20-3, and 16-1, 16-216-
When the AND device of 3 is ON, the furnace temperature target value which is the output of 19 is adopted as the furnace temperature, and when it is OFF, the manually set furnace temperature target value of 20 is adopted as the furnace temperature.

The furnace temperature switched by the automatic/manual switching device for each furnace zone (17) is input to the combustion control device (21).

The combustion control device 21 inputs the target furnace temperature and the actual furnace temperature from 9, and controls the fuel flow rate, air-fuel ratio, etc. in order to bring the furnace temperature to the target value.

The above configuration simplifies the operator's glue start process when starting the furnace temperature control system, and controls the furnace temperature for each furnace zone each time the leading material charged into the heating furnace passes through each furnace zone after restarting. , can automatically switch from manual to automatic.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention. 5 to 7... Material to be heated charged into the heating furnace after furnace temperature control system glue starts, 7... Leading material charged into the heating furnace after restart, 8... When control system glue starts material to be heated.

Claims (1)

[Claims] 1. In a heating furnace that performs furnace temperature control and restart, it focuses on the material to be heated that is first charged into the heating furnace after restarting, and detects when the material passes through the extraction side of each furnace zone in the heating furnace. A heating furnace temperature control method characterized in that temperature control of the detected furnace zone is sequentially switched from manual to automatic.