JPS6319772B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a combustion control device.

Conventionally, for example, as a combustion control device that controls the output steam pressure of a medium-sized or small-sized boiler, a fuel valve for adjusting the fuel flow rate and an air damper for adjusting the air flow rate have been connected using a link mechanism, a cam mechanism, etc. The relationship between the fuel valve opening and fuel flow rate can be determined via a flow meter, and the difference in air flow rate can be determined through a flowmeter by performing a preparatory operation before operating the boiler. Data indicating the relationship between the opening degree of the air damper and the air flow rate is obtained via a pressure gauge, and the connection mechanism is adjusted so that the relationship between the fuel valve and the air damper is approximately in an excess air condition. While operating the boiler,
While detecting the oxygen concentration in the exhaust gas of this boiler,
It is known that the coupling mechanism is configured to be finely adjusted so that the fuel flow rate and the air flow rate have an appropriate relationship.

However, in the conventional combustion control device described above, the relationship between the opening degree of the air damper or fuel valve and the oxygen concentration in the exhaust gas, that is, the amount of air in the burner of the boiler, changes slightly. It is difficult to understand, and the above-mentioned fine adjustment of the coupling mechanism must be performed many times.Therefore, there is a drawback that the operability of the combustion control device is not good.

In particular, even if the fuel valve is set to a certain opening degree, if the opening degree of the fuel valve changes even slightly during adjustment of the above-mentioned connection mechanism, the connection between the fuel valve and the above-mentioned connection mechanism will be interrupted. This has a large effect on the interlocked air damper, making fine adjustment of the coupling mechanism extremely troublesome, requiring skill and skill from the operator, and making the operation of the combustion control device extremely troublesome. It was hot.

This invention has been made to eliminate the above-mentioned drawbacks, and the first object of the invention is to provide data representing the relationship between the opening degree of the fuel valve and the fuel flow rate;
Based on the data representing the relationship between the air damper opening and the air flow rate and the data representing the relationship between the excess air ratio and the fuel flow rate, the fuel valve opening and the air damper opening are automatically set in an appropriate relationship. It is an object of the present invention to provide a combustion control device that can be adjusted so that the combustion device can be operated very simply and properly.

Another object of the present invention is to make it possible to set and change data representing the relationship between the air damper opening degree and the air flow rate by inputting, for example, detected data on the oxygen concentration in the exhaust gas of a combustion device. Therefore, the adjustment operation in the control device is
To provide a combustion control device that can be easily operated without requiring any skill.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the basic configuration of a combustion control device according to the present invention.

In FIG. 1, 1 is a boiler main body of a combustion device. The burner 2 of the boiler body 1 is supplied with liquid fuel from a fuel tank 3 as a fuel source via an electric valve 4 for controlling fuel flow rate, and from a duct 6 equipped with an air damper 5. Air is supplied via a forced air blower 7 and an air preheater 8. From this boiler main body 1, it is sent to various devices, for example, a drying device 10, via a valve 9 for controlling the boiler steam flow rate.

11 is a pressure gauge for detecting boiler steam pressure, which is interposed between the boiler main body 1 and the valve 9;
13 is a potentiometer that operates in conjunction with the operation of the electric valve 4 and sends out a voltage signal indicating the degree of opening of the valve; 13 is a valve regulator that operates the opening and closing of the electric valve 4; 14; 15 is a potentiometer that operates in conjunction with the air damper 5 and sends out a voltage signal indicating the degree of opening of the air damper 5; 15 controls the amount of air flowing into the duct 6 by operating the air damper 5; A damper regulator 16 is installed in the exhaust gas flow path of the boiler main body 1, and an oxygen concentration detector 17 is installed to detect the oxygen concentration in the exhaust gas.
is a flow meter interposed between the oil tank 3 and the electric valve 4 to detect the oil flow rate.

18 is a main control device of the combustion control device, which includes, for example, a read-only memory (ROM) that stores a control program, a random access memory (RAM), an arithmetic circuit that performs various operations,
A microcomputer or the like equipped with a determination circuit or the like is used.

The main controller 18 includes the pressure gauge 11, potentiometers 12 and 14, a data input operation switch (not shown) for inputting various data, various function switches (not shown), etc. It is connected to a console 19 equipped with. This main controller 18 includes the above-mentioned pressure gauge 11, potentiometers 12 and 14, and
From the console 19, the detected value of the steam pressure of the boiler body 1, the opening degree of the electric valve 4, and the air damper 5 are transmitted.
In response to signals representing the opening degree, operation commands, various data, etc. from the console 19, operation control signals are sent to the valve regulator 13 and the damper regulator 15, respectively.

Note that the potentiometer 12 and the valve regulator 13 form a fuel flow rate control loop for the electric valve 4. Further, the potentiometer 14 and the damper regulator 15 form a fuel flow control loop for the air damper 5.

FIG. 2 shows an example of a specific electric circuit of the main controller 18, surrounded by a chain line.

In FIG. 2, the same components as those in the apparatus shown in FIG. 1 described above are given the same reference numerals and will be explained. The central processing circuit (not shown) of the main control device is, for example, a microprocessor, which issues operational instructions to various circuits within the main control device.

In FIG. 2, 21 is a random access memory (RAM), hereinafter simply referred to as memory.

The first area 21-1 of the memory 21 stores data 22-1 representing the steam pressure target value of the control target for the boiler to be controlled, and the steam pressure target value determined by PID (proportional, integral, differential) calculation. Data 22-2 representing a PID constant for calculating a fuel flow rate commensurate with the value is stored. These data 22-1 and 22-2
is input into this first area 21-1 by a data input operation switch (not shown) of the console 19.

For example, as shown in FIG. 3, the second area 21-2 of the memory 21 stores the relationship between the valve opening (%) of the electric valve 4 and the fuel flow rate (%) (percentage of the maximum flow rate of the device). A functional formula representing, for example, is stored in the third area 21-3.
As shown in FIG. 4, a functional expression representing the relationship between the damper opening degree (%) of the air damper 5 and the air flow rate (%) (percentage of the maximum flow rate of the device) is stored.

The above-mentioned two relationships between valve opening - fuel flow rate and air damper opening - air flow rate are determined based on data obtained by preparatory operation before operating the boiler to be controlled. It's getting old.

That is, when performing preparatory operation of the boiler, the oxygen concentration detector 16 and the flow meter 17 that detects the fuel flow rate are put into operation. Then, the expected opening degree (%) 22-3 of the electric valve 4 with respect to the specified fuel flow rate (%) is set in the valve controller 13, and the boiler does not perform incomplete combustion with respect to the specified fuel flow rate (%). So that you can drive without this happening,
Based on empirical predictions, the damper regulator 15:
Set the damper opening degree (%) with sufficient margin for the estimated damper opening degree (%). After that, a preparatory operation of the boiler is performed, and the setting value (%) of the opening degree of the electric valve 4 is set using the potentiometer 12.
Data 22-4 representing the detected value (%) of the fuel flow rate by the flowmeter 17 with respect to 22-3 is obtained. Further, data 22-6 representing the detected value [O ₂ ] of the oxygen concentration in the exhaust gas by the oxygen concentration detector 16 with respect to the set value (%) 22-5 of the opening degree of the air damper 5 by the potentiometer 14 is obtained. moreover,
These data 22-4 and 22-6 are input to the main controller 18 by a data input operation switch (not shown) of the console 19.

As mentioned above, the set value of the valve opening degree (%) and the set value of the damper opening degree corresponding to the set value of the valve opening degree are set, for example, by 5 as shown in FIGS. 3 and 4. Select the type setting value.

As described above, each time a data input operation is performed, an arithmetic circuit (not shown) of the main controller 18 opens a valve as shown in FIGS. 3 and 4 based on the input data. Functional expressions representing the relationships between degree-fuel flow rate and damper opening degree-air flow rate are obtained, and these functional expressions are stored in the second area 21-2 and third area 21-2 of the memory 21, respectively. 3 is stored.

In the above calculation circuit, the detected value [O ₂ ] representing the oxygen concentration in the exhaust gas is converted into a value representing the air flow rate a ₀ according to the following equation.

a ₀ = q×A ₀ ×21/(21−[O ₂ ]) …(1) Here, q is the fuel flow rate and A ₀ is the theoretical air amount.

Further, in the fourth area 21-4 of the memory 21, the relationship between the excess air ratio M and the fuel flow rate (%), which is appropriately set for the boiler, is stored, for example, as shown in FIG. The function formula is memorized. This functional formula is expressed as, for example, the fuel flow rate (%) at three operating points in the boiler.
For each, the excess air ratio M is appropriately selected, and based on the data 22-7 representing the excess air ratio with respect to the fuel flow rate, the arithmetic circuit (not shown) of the main controller 18 is operated in the same manner as described above. This was obtained by

23 is a pressure gauge 11 for detecting data from the first area 21-1 of the memory 21 and steam pressure of the boiler.
a fuel flow calculation circuit that calculates a fuel flow rate that matches the target value of steam pressure of the boiler by performing a known PID calculation based on the detected value from the boiler;
is a valve opening function that calculates the valve opening degree of the electric valve 4 commensurate with the fuel flow rate based on the data representing the fuel flow rate from the arithmetic circuit 23 and the functional formula from the memory 21 and the second area 21-2. The fuel flow rate calculation circuit 25 receives data representing the fuel flow rate from the calculation circuit 23 and the fourth area 21- of the memory 21.
an air flow rate calculation circuit that calculates an air flow rate commensurate with the fuel flow rate based on the functional formula from 4;
A damper opening 6 calculates the opening degree of the air damper 5 commensurate with the air flow rate based on the data representing the air flow rate from the arithmetic circuit 25 and the function equation from the third area 21-3 of the memory 21. It is a degree calculation circuit.

The fuel flow rate calculation circuit 23 is configured to output a signal representing the calculated fuel flow rate only when the absolute value of the amount of change in the fuel flow rate is within a predetermined allowable limit. A known limiter (not shown) is provided.

Further, the calculation in the air flow rate calculation circuit 25 is performed according to the following equation.

Air flow rate A = Q × A ₀ × M ... (2) Here, Q is the fuel flow rate value calculated by the fuel flow rate calculation circuit 23, A ₀ is the theoretical air amount, and M is the fourth area of the memory 21. This is the excess air ratio calculated by substituting the fuel flow rate Q into the functional equation 21-4.

27 receives a signal representing the fuel flow rate output from the arithmetic circuit 23 and determines whether the fuel flow rate represents an increase or decrease from the current fuel flow rate of the boiler. This is a first determination circuit that determines whether the image is represented.

Reference numerals 28 and 29 are analog switches, which output the inputted value as is when turned on, and hold and output the value immediately before being turned off when turned off.

When the sign of the amount of change in fuel flow rate from the arithmetic circuit 23 is positive, the first determination circuit 27 determines that it is an increase amount and switches the first analog switch 2.
On the other hand, when the sign of the amount of change in the fuel flow rate from the arithmetic circuit 23 is negative, it is determined that the amount has decreased, and a command is sent to turn on the second analog switch 29. It is designed to send out signals.

The first analog switch 28 is connected to the first judgment circuit 2
When the damper opening calculation circuit 7 receives an operation command signal and is turned on, the damper opening calculating circuit 26 is connected to apply a signal representing the damper opening to the damper regulator 15 . In this damper regulator 15,
The signal received from the damper opening calculation circuit 26 via the first analog switch 28 is converted into a signal for operating the driving motor 5-1 of the air damper 5, and this converted signal is used to drive the motor 5-1. It is now being applied to

On the other hand, when the second analog switch 29 receives an operation command signal from the first determination circuit 27 and is turned on, it sends a signal representing the valve opening output from the valve opening calculation circuit 24 to the valve regulator 13. connected to apply. This valve regulator 13
Then, the signal received from the valve opening calculation circuit 24 via the second analog switch 29 is converted into a signal for operating the drive motor 4-1 of the electric valve 4, and this converted signal is used to drive the electric valve 4. motor 4
-1 is applied.

30 is a second judgment circuit, and this second judgment circuit 3
0 is connected to receive a signal representing the damper opening degree passed through the first analog switch 28 and a signal representing the damper opening degree of the air damper 5 from the potentiometer 14. Then, when it is determined that the actual opening degree of the air damper 5 becomes equal to the command value indicating the damper opening degree that has passed through the first analog switch 28, an operation command is issued to turn on the other second analog switch 29. A signal is applied to the second analog switch 29.

Further, the second determination circuit 30 receives a signal representing the valve opening degree passed through the second analog switch 29, and also receives a signal representing the valve opening degree of the electric valve 4 from the potentiometer 12. It is connected. Then, when it is determined that the actual opening degree of the electric valve 4 has become equal to the command value indicating the valve opening degree passed through the second analog switch 29, another first analog switch 28 is turned on. A command signal is applied to the first analog switch 28.

Next, the operation of the combustion control device having the above configuration will be explained. Note that this explanation will be given with respect to an example of sampling control.

I Data Input Operation First, by using a data input operation switch (not shown) on the console 19, data 22-1 representing the arbitrarily selected target value of steam pressure of the boiler is inputted into the first area 2 of the memory 21 using a known method.
Enter in 1-1. Also, in the same way, the first
Data 22-2 representing an arbitrarily selected PID constant related to the combustion control is input into the area 21-1.

Next, according to the operation flowchart shown in FIG. 7, the valve opening degree - fuel flow rate, and
Find a function that represents the relationship between damper opening and air flow rate.

In step 1, in the same manner as described above, the fuel flow rate 20, which is appropriately selected, is controlled by the data input operation switch (not shown) on the console 19.
Data 22-3 representing the opening degree of the electric valve 4 approximately corresponding to % is input into the memory 21-2.
Then, for this fuel flow rate of approximately 20%, an air damper 5 is applied that corresponds to an air flow rate that is empirically considered to prevent incomplete combustion in the boiler.
Data 22-5 representing the damper opening degree is input to the third area 21-3 of the memory 21. In addition,
The above fuel flow rate is expressed as a percentage of the maximum fuel flow rate that can be supplied to the burner 2 of the boiler. Further, the valve opening degree and the damper opening degree are each expressed as a percentage of the maximum opening degree.

Hereafter, in the same way, set value of fuel flow rate is 40%,
Data 22- representing valve opening degrees approximately corresponding to 60%, 80%, and 100%, respectively, and damper opening degrees selected in the same manner as described above, corresponding to the set values of each fuel flow rate. 3 and 22-5 are input to the second area 21-2 and third area 21-3 of the memory 21, respectively.
Then proceed to step 2.

In step 2, the boiler operation switch (not shown) on the console 19 is turned on, and the set value of the fuel flow rate initially input into the second area 21-2 of the memory 21 is set as shown by the dotted line in FIG.
The signal representing the valve opening approximately equivalent to 20% is
A signal representing the damper opening degree corresponding to the fuel flow rate setting value of 20%, which is applied to the valve regulator 13 and stored in the third region 21-3, is applied to the damper regulator 15. Based on the output from the valve regulator 13, the electric valve 4
The motor 4-1 for driving the air damper 5 is driven based on the output from the damper regulator 15, and the motor 5-1 for driving the air damper 5 is driven, and the boiler is preparatory for the next step. Proceed to step 3.

In step 3, the fuel flow rate in the above-described combustion state of the boiler is detected by the flow meter 17, and the process proceeds to step 4.

In step 4, data 22-4 representing the fuel flow rate detected by the flowmeter 17 is transferred to the second area 21- of the memory 21 using a data input operation switch (not shown) of the console 19 in the same manner as described above. 2 and proceed to the next step 5.

In step 5, the oxygen concentration in the exhaust gas in the combustion state of the boiler is detected by the oxygen concentration detector 16, and the process proceeds to step 6.

In step 6, in the same manner as described above, the data input operation switch of the console 19 is used to input data 22-6 representing the oxygen concentration in the exhaust gas detected by the oxygen concentration detector 16.
is input into the third area 21-3 of the memory 21. Based on the data [O ₂ ] representing this oxygen concentration, an arithmetic circuit (not shown) in the main controller 18 calculates the data [O ₂ ].
The air flow rate a ₀ corresponding to the above-mentioned second region 21
-2 is calculated using the fuel flow rate data. This calculation is performed according to the above-mentioned equation (1). This calculated air flow rate is then stored in the third area 21-3 of the memory 21. Then proceed to step 7.

In step 7, it is determined whether the operations in steps 2 to 6 have been completed for all fuel flow rate settings set in step 1.

In this step 7, it is determined that the operations in steps 2 to 6 are executed based on the valve opening and damper opening corresponding to the fourth set fuel flow rate of 80%, and the result is NO. When the fuel flow rate is set to 100, the process returns to step 2 and the next fifth set fuel flow rate is 100.
The operations in steps 2 to 6 are executed based on the valve opening degree and damper opening degree corresponding to the %. Then, in step 7, if it is determined as YES that the operations of steps 2 to 6 corresponding to all set values of fuel flow rates have been completed, then the second area 21-2 and the third area 21 of the memory 21 The data input operation for -3 ends.

If the determination in step 7 is YES, an arithmetic circuit (not shown) in the main controller 18 uses a known method to calculate various valve opening degrees stored in the second area 21-2 of the memory 21, and , based on the data representing the fuel flow rate corresponding to each valve opening degree, for example, the third
As shown in the figure, a functional expression representing the relationship between valve opening degree and fuel flow rate is determined. This function formula is
The valve opening degree is expressed using the fuel flow rate as a variable.

Further, in the above-mentioned arithmetic circuit, as described above, based on the data representing various damper opening degrees and the air flow rate corresponding to each damper opening degree stored in the third area 21-3 of the memory 21, For example, as shown in FIG. 4, a functional expression representing the relationship between the damper opening degree and the air flow rate is determined.

The above-mentioned function equations of valve opening-fuel flow rate and damper opening-air flow rate are stored in the second area 21-2 of the memory 21 and, respectively,
It is stored in the third area 21-3.

Next, in the same manner as described above, by using the data input operation switch of the console 19, an appropriately selected excess air ratio M is determined with respect to the fuel flow rate to be supplied to the burner 2 of the boiler to be controlled.
Data 22-7 representing
It is input into area 21-4. For example, as shown in Figure 5, the M value for a fuel flow rate of 20%
1.30, an M value of 1.10 for a fuel flow rate of 40%, and an M value of 1.10 for a fuel flow rate of 100%, are input into the fourth area 21-4. and,
In the same manner as described above, as shown in FIG.
A functional expression expressing the relationship between the fuel flow rate and the excess air ratio M using the fuel flow rate as a variable is determined, and this functional expression is stored in the fourth area 21-4 of the memory 21. Examples of data formats stored in the second area 21-2, third area 21-3, and fourth area 21-4 are shown in FIGS. 6a to 6c. Furthermore, the pitch of the data representing the fuel flow rate and the M value described above are appropriately selected depending on the capacity, type, etc. of the boiler to be controlled.

Combustion control operation of the boiler After performing the various data input operations described above, the combustion control of the boiler is performed according to the operation flowchart shown in FIG.

In the manner described in I, the memory 21
It is assumed that the target value of the steam pressure of the boiler and the PID constant are set in the first region 21-1, and the operation of the boiler is started. Furthermore, a signal representing the detected value of the steam pressure of the boiler output is applied from the pressure gauge 11 to the fuel flow rate calculation circuit 23 of the main controller 18, and it is assumed that the operation of step 1 in FIG. 8 has been executed. do.

The fuel flow rate calculation circuit 23 generates a signal representing a target value of steam pressure from the first area 21-1 in a known manner according to the PID constant from the first area 21-1 of the memory 21; Pressure gauge 11
A PID calculation is performed based on a signal representing a detected value of the steam pressure of the boiler from the control cycle, and a fuel flow rate corresponding to the operation amount of the boiler in the control cycle is calculated. This operation is shown as step 2 in FIG.

The output signal of the arithmetic circuit 23 is applied to a known limiter circuit (not shown), and in the limiter circuit, the absolute value of the amount of change in the fuel flow rate value output from the arithmetic circuit 23 is within a predetermined tolerance range. A determination is made as to whether it is a thing or not. This operation is shown as step 3 in FIG.

Next, a signal representing the fuel flow rate output from the arithmetic circuit 23 is applied to the valve opening degree arithmetic circuit 24 and also to a data readout circuit (not shown). This data reading circuit reads data from the second area 21-2 of the memory 21 based on the fuel flow rate indicated by the signal from the arithmetic circuit 23.
A predetermined functional expression is read out from the above, and a signal representing the read functional expression is applied to the valve opening calculation circuit 24.

For example, when the fuel flow rate output from the arithmetic circuit 23 corresponds to 35 (%), the readout circuit uses a known comparative determination method to
It is determined that the above fuel flow rate of 35% is within the range of the fuel flow rate of 18% to 36% in the data format of FIG. 6a, and the second area 21-2 of the memory 21 corresponding to this range is stored. From address a ₂₃₂ , the function of fuel flow rate - valve opening degree F(x) = 0+
Read 1.167x. In addition, the function F
(x) represents the valve opening degree (%) with the fuel flow rate as a variable x (%), and 1.167 represents the flow rate when the boiler was operated with the valve opening degree of 21% and 42% in the preparatory operation described above. This is a coefficient representing a straight line connecting the operating points P ₁ and P ₂ (shown in FIG. 3) where the fuel flow rate detected by the meter 17 is 18% and 36%.

In this way, the signal representing the function F(x)=0+1.167x read out by the reading circuit is applied to the valve opening calculation circuit 24. Then, in this valve opening calculation circuit 24, according to the function F(x)=0+1.167x,
The variable x of this function F(x) is the fuel flow rate 35
(%), the valve opening [0
+1.167×35〕(%) is calculated.

Further, a signal representing the fuel flow rate output from the arithmetic circuit 23 is applied to the air flow rate arithmetic circuit 25 and also to the readout circuit (not shown) described above. This readout circuit reads out a predetermined functional formula from the fourth area 21-4 of the memory 21 based on the fuel flow rate indicated by the signal from the arithmetic circuit 23, and outputs a signal representing this functional formula in the same manner as described above. is applied to the air flow rate calculation circuit 25.

For example, if the output of the arithmetic circuit 23 corresponds to a fuel flow rate of 35 (%), the readout circuit corresponds to a fuel flow rate of 20% to 40% in the data format of Figure 6c. It is determined that there is, and the fourth area 21-4 of the memory 21
The function F(x)=1.5−0.01x representing the excess air ratio is read from address a ₄₃₁ of . And x
By substituting 35% of the fuel flow rate into , the excess air ratio M=
Calculate 1.15. Based on this excess air ratio M=1.15, the air flow rate for the fuel flow rate is calculated based on the above-mentioned second equation stored in the ROM (not shown). The operations in this arithmetic circuit 25 are shown as steps 4 and 5 in FIG.

Note that a signal representing the air flow rate calculated by the arithmetic circuit 25 is applied to the limiter circuit (not shown), and it is checked whether the air flow rate value is within a predetermined tolerance range. It will be checked. This operation is shown as step 6 in FIG.

Further, a signal representing the air flow rate output from the arithmetic circuit 25 is applied to the damper opening degree arithmetic circuit 26 and also to the readout circuit (not shown) described above. This readout circuit is
In the same manner as described above, based on the air flow rate indicated by the signal from the arithmetic circuit 25, the memory 21
A predetermined functional formula is read from the third region 21-3, and a signal representing this functional formula is applied to the damper opening calculation circuit 26. Then, in this damper opening calculation circuit 26, the function F from the third area 21-3 of the memory 21 is calculated in the same way as in the valve opening calculation circuit 24 described above.
By substituting the air flow rate from the arithmetic circuit 25 into the variable x in equation (x), the damper opening degree of the air damper 5 with respect to the air flow rate is determined.

In this way, the valve opening degree of the electric valve 4 with respect to the fuel flow rate and the damper opening degree of the air damper 5 with respect to the air flow rate are determined in accordance with the operating amount of the boiler in the control cycle. This operation is shown as step 7 in FIG.

Next, the output signal of the fuel flow rate calculation circuit 23 is applied to the first determination circuit 27, and the first determination circuit 27 determines whether the fuel flow rate output from the calculation circuit 23 increases or decreases. It is determined whether This determination is made using a known method, for example,
This is done by determining whether the sign of the amount of change in the fuel flow rate value output from the arithmetic circuit 23 in step 2 is positive or negative. This action
This is shown as step 8 in FIG.

[A] When the fuel flow rate increases When the fuel flow rate output from the arithmetic circuit 23 indicates an increase amount, that is, the determination result in the first determination circuit 27 is YES, the first determination circuit 27 determines that the fuel flow rate increases. , a command signal to turn on the first analog switch 28 is applied, and the switch 28
is turned on.

Therefore, a signal indicating the damper opening command value is applied from the damper opening calculation circuit 26 to the damper regulator 15 via the first analog switch 28. The damper regulator 15 operates the motor 5-1 so that the signal from the potentiometer 14 and the signal from the damper opening calculation circuit 26 match.

Further, at the same time that the first analog switch 28 described above is turned on, a signal representing the damper opening degree passing through the switch 28 is transmitted to the second determination circuit 3.
Also applied to 0.

As a result, the air damper 5
1, the damper is driven to the damper opening degree specified by the arithmetic circuit 26. This operation is shown as step 9-1 in FIG.

Thereafter, the second determination circuit 30 receives a signal representing the current damper opening degree of the air damper 5 from the potentiometer 14 in addition to the signal representing the command value of the damper opening degree from the first analog switch 28. receive. Then, this second determination circuit 30
When it is determined that the signal from the potentiometer 14 matches the signal from the first analog switch 28, step 10 in FIG.
-1, it is judged as YES, and this second
The determination circuit 30 applies a command signal to turn on the second analog switch 29.

After that, the second analog switch 29 mentioned above
When turned on, the arithmetic circuit 24 sends a signal to the valve regulator 13 via the switch 29.
A signal indicating a command value for the valve opening degree of the electric valve 4 is applied. And this valve regulator 13
is the motor 4-1 for driving the electric valve 4,
A drive command signal corresponding to the above command value is applied.

In the valve controller 13, when it is determined that the signal representing the current valve opening from the potentiometer 12 matches the signal representing the command value of the valve opening from the arithmetic circuit 24, the valve The regulator 13 is connected to the motor 4-
1 is stopped.

As a result, the valve opening degree of the electric valve 4 is set to the command value from the arithmetic circuit 24 described above.
This operation is shown as step 12-1 in FIG. Note that in step 10-1, if the signal from the potentiometer 14 does not match the signal from the first analog switch 28, that is, if the determination is NO, the second analog switch 29 Apply a command signal to turn it off. Therefore, the command for setting the opening degree of the electric valve 4 from the valve opening calculation circuit 24 is not input to the valve regulator 13, and the valve opening degree of the electric valve 4 is not changed.

Furthermore, in the second determination circuit 30 described above,
Excess air ratio M (hereinafter referred to as set M value) calculated by the calculation circuit 25 based on the fuel flow rate calculated by the calculation circuit 23 in the control cycle;
The current damper opening degree of the air damper 5 from the potentiometer 14 and the potentiometer 1
Based on the current valve opening degree of the electric valve 4 from 2, an excess air ratio M (hereinafter referred to as the calculated M value) calculated based on the following third equation is compared. Then, when the calculated M value becomes larger than the set M value, as shown in step 11-1 in FIG. 8, the determination is YES, and a command signal to turn on the second analog switch 29 is applied. Therefore, as described above, so that the command value of the valve opening degree calculated by the calculation circuit 24 is obtained,
The valve opening degree of the electric valve 4 is set.

Conversely, when the calculated M value is smaller than the set M value, a negative determination is made in step 11-1, and the setting of the valve opening degree for the electric valve 4 is completed.

The above calculation M value is (air flow rate determined from the current damper opening)/(fuel flow rate determined from the current valve opening) x (theoretical air amount)...
(3).

In addition, in the determination in step 11-1 above, in order to stabilize the combustion control operation,
Considering the operating margin of the control system, a constant α corresponding to, for example, 1% of the set M value and the added value of the set M value are used to compare with the calculated M value described above. Good too.

This completes the control cycle for one sampling, for example, a sampling time of 1 second.

[B] When the fuel flow rate decreases, the fuel flow rate output from the arithmetic circuit 23 is [A]
In contrast to the case of , it shows the amount of decrease. That is, when the determination result in the first determination circuit 27 is NO, the first determination circuit outputs the second analog switch 29, contrary to the case in [A] described above.
A command signal is applied to turn it on.

Thereafter, in the same manner as in case [A] above, the electric valve 4 is adjusted as shown in step 9-2 in FIG. The valve opening degree is set, and then step 12 in Figure 8
As shown in -2, the damper opening degree of the air damper 5 is set.

The operation in the above step 9-2 is similar to the operation in the above step 12-1, and the operation in step 10-2 is the same as the operation in the above step 12-1.
The operation is the same as in step 10-1, and step 11
The operation in step-2 is similar to the operation in step 11-1 described above, and also in step 12-2.
The operation in step 2 is similar to the operation in step 9-1 described above, and these steps
2, 10-2, 11-2, and 12-2 will not be described.

As described above, in the combustion control device having the above configuration, when increasing the fuel flow rate supplied to the burner 2 of the boiler as in case [A], the air damper 5 is opened in accordance with the increase amount. After adjusting the fuel flow rate, the opening degree of the electric valve 4 should be adjusted. Conversely, when reducing the fuel flow rate, it is recommended to adjust the opening degree of the electric valve 4 according to the amount of decrease. After this is completed, the opening degree of the air damper 5 is adjusted. By doing so, it becomes possible to set the M value of the excess air ratio M to the fuel flow rate set in the fourth area 21-4 of the memory 21 to a lower value.
In other words, the amount of air supplied to the burner 2 of the boiler can be made closer to the minimum necessary amount without causing incomplete combustion, and the amount of exhaust gas of the boiler can be suppressed to that extent. Thermal efficiency can be increased.

As is clear from the above explanation, the combustion control device according to the present invention uses the calculation means to calculate the While calculating the fuel flow rate of the combustion device, first data representing the relationship between the fuel flow rate and the opening degree of the electric valve for adjusting the fuel flow rate of the combustion device stored in advance in the storage means, and an air damper for adjusting the air flow rate. Based on second data representing the relationship between the air flow rate and the opening degree of the valve opening and third data representing the relationship between the excess air ratio and the fuel flow rate, the valve opening degree and the damper opening degree are determined according to the fuel flow rate indicated by the output of the calculation means. and actuating the fuel valve operating means for operating the electric valve and the air damper operating means for operating the air damper, respectively, based on the signals representing the valve opening degree and the damper opening degree, respectively.
The output of the combustion device is automatically controlled so as to reach the control target value. Therefore, when operating the combustion device, the operator can adjust the opening of the electric valve for adjusting the fuel flow rate and the air flow rate by simply inputting the specified data according to a predetermined procedure. A signal representing the control amount related to the opening degree of the air damper for use is automatically and appropriately determined based on the first data, second data, and third data obtained by preparatory operation of the combustion equipment. can be obtained without the need for "kan" based on skill or experience,
There is an excellent advantage that the operation of the combustion device can be controlled very simply, quickly and accurately.

Note that switching means is interposed between the calculation means and the fuel valve operation means and the air damper operation means, so that when the amount of change in the fuel flow rate, which is the output of the calculation means, shows an increase, the air operation means is switched on. After the operation of the air damper operating means is completed, the fuel operating means is operated, and when the amount of change in the fuel flow rate shows a decrease, the fuel valve operating means and the air damper operating means are operated in the reverse order. By activating, the set value of the third data indicating the excess air ratio in the combustion device is set.
It can be set near the minimum limit value that does not cause incomplete combustion, which has the excellent advantage of suppressing the amount of exhaust gas and increasing thermal efficiency.

Furthermore, if the second data is set based on the detected value of the oxygen concentration in the exhaust gas of the combustion device and the fuel flow rate value, the control operation characteristics of the combustion control device can be changed as compared to the conventional device. without the need for troublesome adjustment operations as in
Can be changed very easily.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of the configuration of an embodiment of the combustion control device of the present invention, FIG. 2 is a diagram showing an example of a specific electric circuit of the device in FIG. 1, and FIG.
Figure 4 is a graph showing an example of the relationship between valve opening and fuel flow rate that can be used in the device shown in Figure 1; 5 is a graph showing an example of the relationship between fuel flow rate and excess air ratio M that can be used in the device shown in FIG. 1, and FIGS. , a diagram showing an example of first data, second data, and third data; FIG. 7 is an operation flowchart related to a data input operation in the apparatus of FIG. 1; FIG. 8 is a diagram showing an example of first data, second data, and third data.
3 is a flowchart of the control operation of the device shown in FIG. 1...Boiler body, 2...Burner, 3...Fuel tank, 4...Electric valve, 4-1...Motor for driving the valve, 5...Air damper, 5-1...Motor for driving the damper , 9... Valve for controlling steam flow rate of the boiler, 11... Pressure gauge for detecting steam pressure of the boiler, 12... Potentiometer for detecting valve opening, 13... Valve controller, 14... Damper Potentiometer for opening detection, 15... Damper regulator, 16... Oxygen concentration detector, 17... Flow meter for fuel flow rate detection, 18... Main controller, 1
9...Console, 21...Memory, 22-1,
22-2,..., 22-7...data, 23...fuel flow rate calculation circuit, 24...valve opening calculation circuit,
25... Air flow rate calculation circuit, 26... Damper opening calculation circuit, 27... First judgment circuit, 28... First
Analog switch, 29...second analog switch, 30...second determination circuit.

Claims (1)

[Scope of Claims] 1. Valve operating means for operating an electric valve for adjusting the fuel flow rate of a combustion device according to a signal representing the valve opening degree; and an air damper for adjusting the air flow rate for the combustion device according to the damper opening degree. a damper operating means operated in response to a signal representing a control target value for the output of the combustion device, first data representing the relationship between the fuel flow rate and the opening degree of the electric valve; storage means for storing in advance second data representing a relationship between flow rates and third data representing a relationship between excess air ratio and fuel flow rate; a detection means for detecting an output of the combustion device; and a control target for the storage means. fuel flow rate calculation means for calculating the fuel flow rate according to the deviation between the detected value and the detected value by the detection means; and based on the first data, the valve opening degree is calculated according to the fuel flow rate indicated by the output of the fuel flow rate calculation means. Excess air ratio calculation means determines an excess air ratio in accordance with the fuel flow rate indicated by the output of the fuel flow rate calculation means based on the third data; air flow rate calculation means for calculating the air flow rate based on the fuel flow rate indicated by the output of the air flow rate calculation means and the excess air ratio indicated by the output of the excess air ratio calculation means; a damper opening calculation means that determines the damper opening accordingly; and a damper opening calculation means that determines the damper opening according to whether the output of the fuel flow calculation means indicates an increase amount or a decrease amount, the output of the valve opening calculation means is determined by the fuel operation means. applied to, and
The output of the damper opening calculation means is applied to the air operating means, and the first data and the The excess air ratio calculated based on the second data is compared with the value set in the third data so that it is always kept within a predetermined tolerance range.
A combustion control device comprising: control means for controlling each output. 2. The control means operates the fuel operation means after activating the air operation means when the output of the fuel flow rate calculation means indicates an increase amount, while the output of the fuel flow rate calculation means indicates a decrease amount. 2. The combustion control device according to claim 1, wherein the combustion control device is comprised of a switching means that operates the air operation means after the fuel operation means is activated. 3 The second data is the oxygen concentration in the exhaust gas and
2. The combustion control device according to claim 1, wherein the air flow rate is expressed relative to the air damper opening calculated based on the fuel flow rate.