JP2011007398A - Fuel air feed ratio control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel air feed ratio control device capable of appropriately adjusting a flow ratio between a fuel flow rate and a combustion air flow rate while reducing cost.SOLUTION: A fuel control valve 3 for adjusting the fuel flow rate supplied to a burner 2 achieves a linear or approximately linear relationship between a valve opening and the fuel flow rate and includes a valve drive part 3d for adjusting the valve opening. An air control valve 6 for adjusting the combustion air flow rate supplied to the burner 2 achieves a linear or approximately linear relationship between a valve opening and the combustion air flow rate and includes a valve drive part 6d for adjusting the valve opening. A control means 7 controls the valve drive part 3d of the fuel control valve 3 and the valve drive part 6d of the air control valve 6 to adjust the valve opening of the fuel control valve 3 and the valve opening of the air control valve 6 to a valve opening so that the fuel flow rate becomes a flow rate corresponding to combustion load and the flow ratio between the fuel flow rate and the combustion air flow rate becomes a set flow ratio.

Description

The present invention provides a fuel control valve that adjusts the flow rate of fuel supplied to the burner;
An air control valve for adjusting the flow rate of combustion air supplied to the burner;
Control means for controlling the fuel control valve and the air control valve so that the fuel flow rate becomes a flow rate corresponding to the combustion load of the burner and a flow rate ratio between the fuel flow rate and the combustion air flow rate becomes a set flow rate ratio. The present invention relates to a fuel / air supply rate control apparatus.

Such a fuel / air supply amount ratio control device controls a supply amount ratio between fuel supplied to the burner and combustion air, and the burner is used for heating various industrial furnaces, for example.
The fuel control valve and the air control valve are controlled by the control means so that the fuel flow rate becomes a flow rate corresponding to the combustion load of the burner and the flow rate ratio between the fuel flow rate and the combustion air flow rate becomes the set flow rate ratio. It is configured.

In such a fuel air supply amount ratio control device, conventionally, a drive unit for adjusting the valve opening of the air control valve is provided, and in conjunction with the change adjustment of the valve opening of the air control valve by the drive unit, The air control valve and the fuel control valve are connected by a link mechanism so that the opening degree of the fuel control valve is adjusted so that the flow rate ratio between the fuel flow rate and the combustion air flow rate becomes the set flow rate ratio.
When the valve opening of the air control valve is adjusted so that the valve drive unit is controlled by the control means and the combustion air flow rate becomes a flow rate corresponding to the combustion load of the burner, By adjusting the valve opening of the fuel control valve, the fuel control is performed so that the fuel flow rate becomes a flow rate corresponding to the combustion load of the burner and the flow rate ratio between the fuel flow rate and the combustion air flow rate becomes the set flow rate ratio. The valve and the air control valve are configured to be controlled (see, for example, Patent Document 1).

Japanese Patent Publication No. 4-29934

However, in the conventional fuel air supply amount ratio control device, the valve opening of the fuel control valve is appropriately adjusted in conjunction with the adjustment of the valve opening of the air control valve in the entire adjustment range of the valve opening of the air control valve. It is necessary to adjust the link mechanism as described above, and the adjustment is complicated and skill is required for the adjustment, and setting change and maintenance are difficult. Furthermore, even if the link mechanism is adjusted appropriately, there is a limit to the air ratio adjustment range that can be covered by the link mechanism. Here, the air ratio means a ratio between a minimum theoretical air amount necessary for complete combustion of fuel and an air amount actually supplied.
In addition, the flow rate ratio between the fuel flow rate and the combustion air flow rate may deviate from the set flow rate ratio due to looseness of the connecting portion of the link mechanism.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel air supply amount ratio control device that can appropriately adjust the flow rate ratio between the fuel flow rate and the combustion air flow rate while reducing the cost. It is to provide.

The fuel air supply amount ratio control device of the present invention includes a fuel control valve that adjusts the flow rate of fuel supplied to the burner,
An air control valve for adjusting the flow rate of combustion air supplied to the burner;
Control means for controlling the fuel control valve and the air control valve so that the fuel flow rate becomes a flow rate corresponding to the combustion load of the burner and a flow rate ratio between the fuel flow rate and the combustion air flow rate becomes a set flow rate ratio. Are provided, and
In the first characteristic configuration, the fuel control valve is configured so that a relationship between a valve opening and the fuel flow rate is linear or substantially linear, and includes a valve driving unit that adjusts the valve opening.
The air control valve has a linear or substantially linear relationship between the valve opening and the combustion air flow rate, and includes a valve drive unit that adjusts the valve opening.
The control means converts the valve opening of the fuel control valve and the valve opening of the air control valve to a valve opening at which the fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio. In order to adjust, the valve drive unit of the fuel control valve and the valve drive unit of the air control valve are controlled.

That is, since the fuel control valve is configured so that the relationship between the valve opening and the fuel flow rate is linear or substantially linear and includes a valve driving unit that adjusts the valve opening, The valve opening of the fuel control valve is set to the target valve opening by operating the valve drive unit in a state where the change speed is known (a state in which the change speed is specified) and managing the operation time of the valve drive unit. It is possible to adjust the fuel flow rate supplied to the burner to the target flow rate.
Similarly, the air control valve has a linear or substantially linear relationship between the valve opening and the combustion air flow rate, and is configured to include a valve drive unit that adjusts the valve opening. The valve opening of the air control valve is set to the target valve by operating the valve drive in a state where the change speed of the opening is known (state in which the change speed is specified) and managing the operation time of the valve drive. It is possible to adjust the flow rate of combustion air supplied to the burner to a target flow rate by adjusting the opening. Incidentally, the opening degree of each of the fuel control valve and the air control valve is expressed as a ratio with respect to the fully opened state. For example, the valve opening degree in the fully closed state is 0% and the valve opening degree in the fully opened state is 100%. expressed.

That is, the control means controls the valve drive unit of the fuel control valve so as to manage the operation time in a state where the valve opening change speed of the fuel control valve is known, and the valve opening change speed of the air control valve is By configuring the valve drive part of the air control valve to control the operation time in the known state, a fuel flow rate detection means and a combustion air flow rate detection means are provided, and based on the respective detection information Without using expensive feedback control that controls the valve drive part of the fuel control valve and the valve drive part of the air control valve, the fuel flow rate can be adjusted to the combustion load. It is possible to adjust the valve opening so that the flow rate is adjusted and the flow rate ratio is the set flow rate ratio.
Then, by independently adjusting the valve opening degree of each of the fuel control valve and the air control valve by a dedicated valve drive unit for each of the fuel control valve and the air control valve, the conventional link mechanism is not used. The fuel flow rate and the combustion air flow rate can be appropriately adjusted, and the flow rate ratio thereof can be appropriately adjusted to the set flow rate ratio.
Accordingly, it is possible to provide a fuel air supply amount ratio control device that can appropriately adjust the flow rate ratio between the fuel flow rate and the combustion air flow rate while reducing the cost.

In addition to the first feature configuration, the second feature configuration is
The valve opening changing speed for each of the fuel control valve and the air control valve is between the minimum valve opening when the combustion load is the minimum combustion load and the maximum valve opening when the combustion load is the maximum combustion load. The transition time is determined to be the same speed for the fuel control valve and the air control valve,
The control means operates the fuel control valve and the air control valve at the valve opening change speeds determined for the same time for the same time, and causes the valve drive unit of the fuel control valve and the valve drive unit of the air control valve to operate. By controlling the valve opening of the fuel control valve and the valve opening of the air control valve, the fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio. The point is to adjust.

That is, the valve opening changing speed of each of the fuel control valve and the air control valve is set to a speed at which the transition time between the minimum valve opening and the maximum valve opening is the same between the fuel control valve and the air control valve. It is done.
Then, the control means operates the fuel control valve and the air control valve at the valve opening change speeds determined for the same time for the same time, thereby controlling the valve drive unit of the fuel control valve and the valve drive unit of the air control valve. Thus, the valve opening degree of the fuel control valve and the valve opening degree of the air control valve are adjusted to the valve opening degree at which the fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio.

In this way, by adjusting the valve opening of each of the fuel control valve and the air control valve, the valve opening of each of the fuel control valve and the air control valve is adjusted from the current valve opening to the target valve opening. Even during the valve opening adjustment transient period, the flow rate ratio between the fuel flow rate and the combustion air flow rate can be adjusted appropriately.
Incidentally, unlike the configuration of the present application, the valve opening changing speeds of the fuel control valve and the air control valve are different from each other in the transition time between the minimum valve opening and the maximum valve opening between the fuel control valve and the air control valve. In such a case, when the valve opening is adjusted from the current valve opening to the target valve opening, one of the fuel control valve and the air control valve is set to the target valve opening. However, there is a period in which the other valve opening does not reach the target valve opening. In such a period, the actual combustion air flow rate is excessive or insufficient with respect to the appropriate combustion air flow rate with respect to the fuel flow rate, and the flow rate ratio between the fuel flow rate and the combustion air flow rate is adjusted appropriately. Can not do it.
Accordingly, the flow rate ratio between the fuel flow rate and the combustion air flow rate should be adjusted appropriately even during the valve opening adjustment transition period in which the valve opening of each of the fuel control valve and the air control valve is adjusted to the target valve opening. Can now.

The third feature configuration is in addition to the second feature configuration,
The difference in opening between the minimum valve opening and the maximum valve opening in the fuel control valve is different from the opening difference between the minimum valve opening and the maximum valve opening in the air control valve. .

At the minimum combustion load, the absolute amount of the combustion air flow rate is small and the combustion air shortage is likely to occur.Therefore, the flow rate ratio between the fuel flow rate and the combustion air flow rate at the minimum combustion load is set to the maximum combustion load. For example, in such a case, an opening difference between the minimum valve opening and the maximum valve opening in the fuel control valve, and a minimum valve opening and a maximum in the air control valve may be set. The opening difference from the valve opening is different.
Even when the difference in opening between the minimum valve opening and the maximum valve opening is different between the fuel control valve and the air control valve, the fuel control valve and the air control valve as in the second feature configuration described above. The fuel control valve and the air control valve are controlled to change the valve opening at the valve opening changing speed determined for each, so that the fuel can be adjusted even during the valve opening adjustment transition period. The flow rate ratio between the flow rate and the combustion air flow rate can be adjusted appropriately.
Therefore, even when the flow rate ratio between the fuel flow rate and the combustion air flow rate is set to be different between the minimum combustion load and the maximum combustion load, the valve opening degree of each of the fuel control valve and the air control valve is the target. The flow rate ratio between the fuel flow rate and the combustion air flow rate can be appropriately adjusted even during the valve opening adjustment transition period adjusted to the valve opening.

In addition to the second or third feature configuration, the fourth feature configuration is
The control means is configured to be able to change and set the transition time.

That is, the transition time between the minimum valve opening and the maximum valve opening may be set differently depending on the heating conditions for heating the heating object.
For example, when the fluctuation of the combustion load is large, in order to quickly change the burner combustion amount and respond quickly to the fluctuation of the combustion load, the transition time is set short and the valve opening change speed is set large. When the fluctuation of the valve is small, in order to reduce the overshoot of the heating temperature due to the change adjustment of the burner combustion amount, the transition time is set long and the valve opening change speed is set small.
And even if the transition time between the minimum valve opening and the maximum valve opening is changed in this way, the valve opening of each of the fuel control valve and the air control valve is set as in the second characteristic configuration. By controlling the valve drive parts of the fuel control valve and the air control valve so as to change at the valve opening changing speed determined for The flow rate ratio can be adjusted appropriately.
Therefore, while allowing the transition time between the minimum valve opening and the maximum valve opening to be changed and set according to the heating conditions etc., the valve opening of each of the fuel control valve and the air control valve is the target valve opening. The flow rate ratio between the fuel flow rate and the combustion air flow rate can be appropriately adjusted even during the valve opening adjustment transition period adjusted to.

In addition to any one of the second to fourth feature configurations, the fifth feature configuration is
Mode command means is provided for commanding any one operation mode from a plurality of operation modes in which at least one of the minimum combustion load and the maximum combustion load is different and the combustion load adjustment range is different,
Corresponding to each of the plurality of operation modes, the valve opening change speed is determined for each of the fuel control valve and the air control valve,
The control means operates each of the fuel control valve and the air control valve at a valve opening change speed of each of the fuel control valve and the air control valve corresponding to the operation mode commanded by the mode command means. Therefore, the valve drive unit of the fuel control valve and the valve drive unit of the air control valve are controlled.

That is, any one operation mode is commanded from the plurality of operation modes having different combustion load adjustment ranges by the mode command means.
Then, in order to operate the fuel control valve and the air control valve by the control means at the valve opening changing speed of each of the fuel control valve and the air control valve corresponding to the operation mode commanded by the mode command means. The valve drive unit of the control valve and the valve drive unit of the air control valve are controlled.

For example, if the type of heat treatment for heating the object to be heated is different, the heating temperature and the adjustment range of the heating temperature are different, so at least one of the minimum combustion load and the maximum combustion load is determined according to the type of heat treatment. By making them different, a plurality of operation modes having different combustion load adjustment ranges are set.
Then, a mode command means for commanding any one of the plurality of operation modes is provided, and the burner combustion amount is set within the combustion load adjustment range set in the operation mode commanded by the mode command means. By controlling, the combustion amount of the burner can be controlled within the combustion load adjustment range corresponding to the heat treatment, and versatility can be improved.

Thus, even when the operation of the burner is controlled in an operation mode arbitrarily selected from a plurality of operation modes having different combustion load adjustment ranges, based on the conditions set in the arbitrarily selected operation mode, As in the second feature configuration, the valve opening changing speeds of the fuel control valve and the air control valve are determined, and the fuel control valve and the air control valve are respectively set at the valve opening changing speeds determined for each. By controlling the valve drive parts of the fuel control valve and the air control valve so as to change the valve opening of the valve, the flow rate ratio between the fuel flow rate and the combustion air flow rate is appropriately adjusted even during the valve opening adjustment transition period. Can be adjusted.
Therefore, even when the burner combustion amount can be adjusted in an operation mode arbitrarily selected from a plurality of operation modes having different combustion load adjustment ranges, and the versatility is improved, each of the fuel control valve and the air control valve Even during the valve opening adjustment transition period in which the valve opening is adjusted to the target valve opening, the flow rate ratio between the fuel flow rate and the combustion air flow rate can be adjusted appropriately.

The block diagram of the fuel air supply amount ratio control apparatus concerning embodiment The figure which shows the principal part of the display screen of a display part Diagram showing the relationship between valve opening and flow rate The figure which shows the relationship between the open / close time of the fuel control valve and the air control valve, the combustion load, and the set air ratio

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the fuel / air supply amount ratio control device supplies a fuel control valve 3 that adjusts the flow rate of gas fuel supplied to the burner 2 through the fuel supply path 1 and the air supply path 4 from the combustion blower 5. The air control valve 6 for adjusting the combustion air flow rate, the gas fuel flow rate is a flow rate corresponding to the combustion load of the burner 2, and the flow rate ratio between the gas fuel flow rate and the combustion air flow rate is the set flow rate ratio. A control unit (corresponding to control means) 7 for controlling the fuel control valve 3 and the air control valve 6 and an operation unit 8 that can communicate with the control unit 7 are provided.

In this embodiment, the burner 2 is provided for heating the furnace 9 on the furnace wall 9w of the furnace 9 to be heated.
In this embodiment, two burners 2 are provided on the furnace wall 9w of the furnace 9 to be heated, and the fuel control valve 3 and the air control valve 6 are provided corresponding to the two burners 2, respectively. In the following description, when the two burners 2 are distinguished and described, they are referred to as a first burner 2a and a second burner 2b.
The fuel supply path 1 is connected to, for example, a city gas pipe (not shown) to which city gas (gas such as 13A, which contains methane gas (CH ₄ ) as a main component) is supplied. 2 is supplied.
A fuel main valve 10 is provided in the fuel supply path 1 at a portion upstream from the branching point for the two burners 2 to collectively and intermittently supply gas fuel to the two burners 2.
A furnace temperature sensor 11 for detecting the temperature in the furnace is provided, and the detection information of the furnace temperature sensor 11 is input to the control unit 7.

In the present invention, the fuel control valve 3 has a linear relationship between the valve opening and the gas fuel flow rate, and is configured to include a valve drive unit 3d that adjusts the valve opening.
Further, the air control valve 6 is configured to include a valve drive unit 6d that adjusts the valve opening degree, in which the relationship between the valve opening degree and the combustion air flow rate is linear. As such a fuel control valve 3 and air control valve 6, a ball valve, a gate valve, etc. are employable.
And the control part 7 adjusts the valve opening degree of the fuel control valve 3 and the valve opening degree of the air control valve 6 to the valve opening degree where the gas fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio. Accordingly, the valve drive unit 3d of the fuel control valve 3 and the valve drive unit 6d of the air control valve 6 are controlled.

In this embodiment, the valve opening changing speed for adjusting the combustion amount for each of the fuel control valve 3 and the air control valve 6 is the minimum valve opening when the combustion load is the minimum combustion load and the combustion load is the maximum combustion load. The transition time between the fuel control valve 3 and the air control valve 6 is determined to be the same speed.
Then, the control unit 7 operates the valve control unit 3d of the fuel control valve 3 and the fuel control valve 3 and the air control valve 6 so that the fuel control valve 3 and the air control valve 6 are operated for the same time at the valve opening changing speed for adjusting the combustion amount. By controlling the valve drive unit 6d of the air control valve 6, the valve opening degree of the fuel control valve 3 and the valve opening degree of the air control valve 6 are set so that the gas fuel flow rate corresponds to the combustion load and the flow rate ratio is the set flow rate. It is comprised so that it may adjust to the valve opening used as a ratio.

A description will be given of each part of the fuel / air supply amount ratio control device.
The fuel control valve 3 is constituted by an electric ball valve provided with a valve drive unit 3d made of an electric motor, and the relationship between the valve opening and the gas fuel flow rate is linear as shown in FIG.
The air control valve 6 is also constituted by an electric ball valve including a valve drive unit 6d made of an electric motor, and the relationship between the valve opening and the combustion air flow rate is linear as shown in FIG.
The electric ball valves constituting each of the fuel control valve 3 and the air control valve 6 are configured so as to be able to block the flow of fluid in a fully closed state.
Incidentally, the valve opening degree of each of the fuel control valve 3 and the air control valve 6 is expressed as a percentage with the valve opening degree in the fully closed state being 0% and the valve opening degree in the fully open state being 100%.

As shown in FIG. 3, for example, in the case of the A operation mode described later, for the fuel control valve 3, the minimum valve opening when the combustion load is the minimum combustion load is 38%, and the maximum when the combustion load is the maximum combustion load. The valve opening is set to 85%, and the air control valve 6 has a minimum valve opening of 41% when the combustion load is the minimum combustion load and a maximum valve opening of 96 when the combustion load is the maximum combustion load. % Is set respectively.
That is, the opening difference between the minimum valve opening and the maximum valve opening in the fuel control valve 3 is 47% of the fully open state, and the difference between the minimum valve opening and the maximum valve opening in the air control valve 6 is The opening difference is 55% of the fully opened state, and the opening difference between the minimum valve opening and the maximum valve opening is different between the fuel control valve 3 and the air control valve 6.

The transition time between the minimum valve opening and the maximum valve opening, that is, the time required to increase the valve opening from the minimum valve opening to the maximum valve opening, and the valve opening The time required to reduce from the opening to the minimum valve opening is, for example, 30 seconds.
In this case, the valve opening changing speed for adjusting the combustion amount in the fuel control valve 3 is set to 1.57% / second, and the valve opening changing speed for adjusting the combustion amount in the air control valve 6 is 1.83. % / Second will be set.

Further, in this embodiment, it is configured such that two types of operation modes having different combustion load adjustment ranges can be set when at least one of the minimum combustion load and the maximum combustion load is different. Incidentally, in the following, when the two types of operation modes are distinguished and described, they are referred to as an A operation mode and a B operation mode.
As shown in FIG. 1, a mode command unit 12 is provided in the operation unit 8 as mode command means for commanding one of the two operation modes. That is, the mode command unit 12 is configured to command one of the A operation mode and the B operation mode.

Next, a description will be given of how to set the operation mode.
That is, for each operation mode, a mode consisting of a minimum valve opening and a maximum valve opening for each of the fuel control valve 3 and the air control valve 6 and a transition time common to the fuel control valve 3 and the air control valve 6. It is configured so that conditions can be set.
Incidentally, the minimum valve opening and the maximum valve opening set for the fuel control valve 3 are the valve opening for flowing gas fuel at a flow rate corresponding to the minimum combustion load, and the gas fuel at a flow rate corresponding to the maximum combustion load, respectively. The minimum valve opening and the maximum valve opening set for the air control valve 6 are respectively the air ratio at the time of the minimum combustion load with respect to the gas fuel flow rate corresponding to the minimum combustion load. The valve opening for flowing the combustion air at a flow rate, and the valve opening for flowing the combustion air at a flow rate that corresponds to the maximum combustion load air ratio with respect to the gas fuel flow rate corresponding to the maximum combustion load.
Incidentally, the air ratio at the minimum combustion load and the air ratio at the maximum combustion load may be set to the same value, or may be set to different values.

Further, each of the two burners 2 is configured so that the mode conditions of the A operation mode and the B operation mode can be set.
And the mode conditions of each operation mode can be set to different conditions by the two burners 2.
That is, in each operation mode, any or all of the minimum valve opening and the maximum valve opening of the fuel control valve 3, the minimum valve opening and the maximum valve opening of the air control valve 6, and the transition time. Can be set to different values by the two burners 2.
For example, the burner 2 on the inlet side of the furnace 9 has a larger combustion load than the burner 2 on the back side, and the combustion load is likely to fluctuate. Therefore, the minimum valve opening and the maximum valve opening of each of the fuel control valve 3 and the air control valve 6 corresponding to the burner 2 on the inlet side are respectively set to the fuel control valve 3 and the air control valve 6 corresponding to the back burner 2. And the transition time corresponding to the inlet-side burner 2 is set to be shorter than the transition time corresponding to the back-side burner 2, the inlet-side burner 2 It is possible to speed up the response to fluctuations in the combustion load.

In addition, an operation mode can be set for each type of heat treatment performed in the furnace 9, and mode conditions of the operation mode can be set according to the type of heat treatment.
For example, when performing a quenching process and a tempering process as the heating process, the quenching process requires a higher temperature than the tempering process, so the minimum valve opening and the maximum valve opening of the fuel control valve 3 and the air control valve 6 respectively. Is set so that the operation mode corresponding to the quenching process is larger than the operation mode corresponding to the tempering process.

As shown in FIGS. 1 and 2, the operation unit 8 has an operation switch 13 for instructing start and stop of a heating operation for heating the furnace 9, and two operation modes for each of the two burners 2. A mode condition setting unit 14 for setting mode conditions, a display unit 15 for displaying mode conditions set by the mode condition setting unit 14, and a heating temperature setting unit 16 for setting a heating target temperature of the furnace 9 Etc. are provided.
FIG. 2 shows details of the screen of the display unit 15 in a state in which the mode condition is displayed. In FIG. 2, the mode condition for the first burner 2a of the two burners 2 is shown. Only the display area is shown, and the display area of the mode condition for the second burner 2b is omitted.
Although not shown, the operation unit 8 is also provided with a display screen switching unit for switching the display screen of the display unit 15 to a screen for displaying mode conditions.

  As shown in FIG. 2, on the screen of the display unit 15 displaying the mode conditions, the minimum valve opening and the maximum valve opening of the fuel control valve 3 set by the mode condition setting unit 14 for the A operation mode. In addition, display areas 15a to 15e for displaying the minimum valve opening, the maximum valve opening, and the transition time of the air control valve 6 are provided, and the fuel control set by the mode condition setting unit 14 for the B operation mode. Display areas 15f to 15j for displaying the minimum valve opening and the maximum valve opening of the valve 3, the minimum valve opening and the maximum valve opening of the air control valve 6, and the transition time are provided.

Although detailed illustration is omitted, the mode condition setting unit 14 selects the first burner 2a or the second burner 2b and the A operation mode or the B operation mode, and in each selected state, the fuel control valve 3 The minimum valve opening and the maximum valve opening, the minimum valve opening and the maximum valve opening of the air control valve 6, and the transition time can be input.
That is, for each burner 2, the minimum valve opening and the maximum valve opening of the fuel control valve 3, the minimum valve opening and the maximum valve opening of the air control valve 6, and the transition time for each of a plurality of operation modes. Can be set.

As shown in FIGS. 2 and 3, for example, in the A operation mode of the first burner 2a, the minimum valve opening and the maximum valve opening of the fuel control valve 3 are set to 38% and 85%, respectively. The minimum valve opening and the maximum valve opening of the valve 6 are set to 41% and 96%, respectively, and the transition time is set to 30 seconds.
In the B operation mode of the first burner 2a, the minimum valve opening and the maximum valve opening of the fuel control valve 3 are set to 12% and 55%, respectively, and the minimum valve opening and the maximum valve of the air control valve 6 are set. The opening is set to 19% and 63%, respectively, and the transition time is set to 25 seconds.

In the A operation mode of the first burner 2a, the opening difference between the minimum valve opening and the maximum valve opening in the fuel control valve 3 is 47% of the fully open state, and the transition time is 30 seconds. The valve opening changing speed for adjusting the combustion amount is set to 1.57% / second, and the opening difference between the minimum valve opening and the maximum valve opening in the air control valve 6 is 55% of the fully opened state. Thus, since the transition time is 30 seconds, the valve opening changing speed for adjusting the combustion amount is set to 1.83% / second.
Further, in the B operation mode of the first burner 2a, the opening difference between the minimum valve opening and the maximum valve opening in the fuel control valve 3 is 43% of the fully opened state, and the transition time is 25 seconds. The valve opening changing speed for adjusting the combustion amount is set to 1.72% / second, and the opening difference between the minimum valve opening and the maximum valve opening in the air control valve 6 is 44% of the fully opened state. Thus, since the transition time is 25 seconds, the valve opening changing speed for adjusting the combustion amount is set to 1.76% / second.
Incidentally, the control unit 7 performs a plurality of fuel control valves 3 and a plurality of air control valves 6 for each of the plurality of burners 2 based on the mode conditions as described above set by the mode condition setting unit 14. The valve opening changing speed for adjusting the combustion amount in each operation mode is obtained.
That is, the mode condition setting unit 14 can change and set the transition time between the minimum valve opening and the maximum valve opening, and the control unit 7 can set the transition time set by the mode condition setting unit 14 based on the transition time. Since the fuel control valve 3 and the air control valve 6 are each configured to obtain the valve opening changing speed for adjusting the combustion amount, the control unit 7 is configured so as to reduce the difference between the minimum valve opening and the maximum valve opening. The transition time can be changed and set.

Next, the control operation of the control unit 7 will be described.
When the start of the heating operation is commanded by the operation switch 13, the controller 7 operates the combustion blower 5, opens the air control valve 6 corresponding to each burner 2, and then ignites corresponding to each burner 2. A plug (not shown) is operated, and the fuel control valve 3 corresponding to the fuel source valve 10 and each burner 2 is opened to ignite each burner 2 to start the heating operation, and the operation switch 13 When the stop of the heating operation is instructed, the combustion blower 5 is stopped, the fuel source valve 10, the fuel control valve 3 and the air control valve 6 corresponding to each burner 2 are closed, and each burner 2 is extinguished. By doing so, the heating operation is stopped.
And the control part 7 calculates | requires a combustion load based on the heating target temperature set in the heating temperature setting part 16, and the detected temperature of the furnace temperature sensor 11 for every setting period during execution of a heating operation. Then, the combustion amount adjustment control for adjusting the combustion amount of each burner 2 according to the determined combustion load and adjusting the flow rate ratio between the gas fuel flow rate and the combustion air flow rate is executed.
In this embodiment, an air ratio is used as a flow rate ratio between the gas fuel flow rate and the combustion air flow rate. Here, the air ratio means a ratio between a minimum theoretical air amount necessary for complete combustion of fuel and an air amount actually supplied.

A description will be given of the combustion amount adjustment control.
The opening degree of each of the fuel control valve 3 and the air control valve 6 at the start of the heating operation, that is, when the burner 2 is ignited is, for example, each of the fuel control valve 3 and the air control valve 6. The maximum valve opening is set.
Further, at the start of the heating operation, the starting valve opening changing speed for adjusting the valve opening from the closed state to the starting valve opening is different for each of the fuel control valve 3 and the air control valve 6. The maximum speed at which the valve opening can be changed by the valve drive units 3d and 6d is set.

  The control unit 7 changes the valve opening of the fuel control valve 3 at a valve opening changing speed for adjusting the combustion amount of the fuel control valve 3 corresponding to the operation mode commanded by the mode command unit 12. The drive speed of the valve drive unit 3d of the fuel control valve 3 is obtained as a combustion speed adjusting drive speed, and the air opening degree of the air control valve 6 is the air corresponding to the operation mode commanded by the mode command unit 12. The driving speed of the valve drive unit 6d of the air control valve 6 for changing at the valve opening changing speed for adjusting the combustion amount of the control valve 6 is obtained as the driving speed for adjusting the combustion amount.

Further, the control unit 7 determines the combustion load according to the deviation between the heating target temperature and the temperature detected by the furnace temperature sensor 11.
For example, when the detected temperature of the furnace temperature sensor 11 is equal to or higher than the heating target temperature, the combustion load is 0. When the detected temperature of the furnace temperature sensor 11 is lower than the heating target temperature, the combustion load increases as the deviation increases. The combustion load is obtained in a plurality of stages by a percentage or the like.
Further, the control unit 7 is instructed by the mode command unit 12 to determine the valve opening degree of the fuel control valve 3 corresponding to a plurality of stages of combustion loads (hereinafter sometimes referred to as a combustion load corresponding valve opening degree). Between the minimum valve opening and the maximum valve opening of the fuel control valve 3 corresponding to the operation mode being set, a plurality of stages are set at equal intervals and at the same number of stages as the combustion load.

For example, when the combustion load is set to 11 steps every 10% between 0 and 100%, the opening degree corresponding to the combustion load of the fuel control valve 3 is set to the operation mode commanded by the mode command unit 12. 11 steps are set at equal intervals between the minimum valve opening and the maximum valve opening of the corresponding fuel control valve 3.
For example, when the A operation mode is commanded by the mode command unit 12, as described above, if the combustion load is set at 11 steps every 10% between 0 and 100%, for example, combustion The minimum valve opening of the fuel control valve 3 is the opening degree corresponding to the combustion load when the load is 0%, the opening degree corresponding to the combustion load when the load is 50%, and the opening degree corresponding to the combustion load when the load is 100%. Are set to 38%, 61.5%, and 85% which is the maximum valve opening degree of the fuel control valve 3.

  Then, at the start of the heating operation, the control unit 7 opens the start time valve opening from the closed state to the start valve opening set corresponding to the fuel control valve 3. The valve drive unit 3d of the fuel control valve 3 is controlled in order to change and adjust at a change speed, and the valve opening degree of the air control valve 6 is set corresponding to the air control valve 6 from the closed state. The valve drive unit 6d of the air control valve 6 is controlled so as to change and adjust the starting valve opening at the start valve opening changing speed.

  Thereafter, the control unit 7 obtains the combustion load every time the set cycle elapses, obtains the combustion load corresponding valve opening degree of the fuel control valve 3 corresponding to the obtained combustion load, and further determines the valve of the fuel control valve 3. The opening is changed from the current valve opening to the combustion load corresponding valve opening at the valve opening changing speed for adjusting the combustion amount of the fuel control valve 3 corresponding to the operation mode commanded by the mode command unit 12. Is calculated on the side closer to the combustion load corresponding valve opening (i.e., the valve drive part 3d of the fuel control valve 3). The valve opening degree is operated for a period of time for changing the valve opening degree at the drive speed for adjusting the combustion amount for the fuel control valve on the side to be changed to the side on which the valve opening degree is increased or decreased, and the valve drive of the air control valve 6 is performed. 6d is placed on the side where the valve opening is changed to the same side as the valve opening changing side of the fuel control valve 3. Actuated by the combustion amount adjusting drive speed for the valve opening degree for changing time.

That is, as described above, the control unit 7 operates the fuel control valve 3 and the air control valve 6 so that the fuel control valve 3 and the air control valve 6 are operated for the same time at the valve opening changing speed for adjusting the combustion amount. By controlling the valve drive unit 3d and the valve drive unit 6d of the air control valve 6, the valve opening degree of the fuel control valve 3 and the valve opening degree of the air control valve 6 are changed so that the gas fuel flow rate becomes a flow rate according to the combustion load. The flow rate ratio is configured to be adjusted to the valve opening degree that becomes the set flow rate ratio.
Further, the control unit 7 controls the fuel control valve 3 and the air control valve 6 at the valve opening changing speeds of the fuel control valve 3 and the air control valve 6 corresponding to the operation mode commanded by the mode command unit 12. In order to operate, the valve drive unit 3d of the fuel control valve 3 and the valve drive unit 6d of the air control valve 6 are controlled.

For example, in the case where the A operation mode is commanded by the mode command unit 12, the adjustment of the valve opening degrees of the fuel control valve 3 and the air control valve 6 corresponding to the first burner 2a will be described as an example.
For example, the starting valve opening degree of the fuel control valve 3 is set to 85% that is the maximum valve opening degree, and the starting valve opening degree of the air control valve 6 is set to 96% that is the maximum valve opening degree. Suppose that
Then, at the start of the heating operation, the control unit 7 changes the valve opening degree of the fuel control valve 3 from the closed state to 85% that is the starting valve opening degree for the fuel control valve. In order to adjust, the valve drive unit 3d of the fuel control valve 3 is controlled, and the valve opening of the air control valve 6 is changed from the closed state to 96% which is the opening valve opening for the air control valve. The valve drive unit 6d of the air control valve 6 is controlled so as to adjust at the starting valve opening changing speed.
Subsequently, when the set period elapses, the control unit 7 obtains the combustion load, and when the combustion load is 50%, the control unit 7 sets the combustion load corresponding valve opening degree of the fuel control valve 3 corresponding to the combustion load to 61.5. %, And the valve opening of the fuel control valve 3 is changed from 85% at present to 61.5% of the valve opening corresponding to the combustion load, which is a valve opening changing speed for adjusting the combustion amount, 1.57% / second. The time required for changing the valve opening required for the change is obtained as 15 seconds.
Then, the control unit 7 sets the valve drive unit 3d of the fuel control valve 3 to a side where the valve opening is changed to a side closer to the combustion load corresponding valve opening at a combustion amount adjusting drive speed for the fuel control valve. The valve drive unit 6d of the air control valve 6 is operated for a second and the combustion speed adjustment drive speed for the air control valve is changed to the side where the valve opening is changed to the same side as the valve opening change side of the fuel control valve 3. Operate for 15 seconds.
Thereafter, the control unit 7 repeats the above-described control every time the set cycle elapses.

Next, as described above, when the valve openings of the fuel control valve 3 and the air control valve 6 are adjusted according to the combustion load, a description will be given of the set air ratio set according to the combustion load.
For example, the gas fuel flow rate at the minimum combustion load is set to 1 m ³ (standard state) / h, the set air ratio at the minimum combustion load is set to 1.3, and the gas fuel flow rate at the maximum combustion load is set to 10 m ^3. The case where the set air ratio at the maximum combustion load is set to 1.1 in (standard state) / h will be described as an example.

In this case, the minimum valve opening of the fuel control valve 3 is set to a valve opening at which the gas fuel flow rate is 1 m ³ (standard state) / h, and the minimum valve opening of the air control valve 6 is 1 m ³ (standard). State) / h is set to a valve opening for flowing combustion air at a flow rate (13.91 m ³ (standard state) / h) at which the air ratio is 1.3 with respect to the gas fuel flow rate.
The maximum valve opening of the fuel control valve 3 is set to a valve opening at which the gas fuel flow rate is 10 m ³ (standard state) / h, and the maximum valve opening of the air control valve 6 is 10 m ³ (standard state). ) / H is set to a valve opening for flowing combustion air at a flow rate (117.7 m ³ (standard state) / h) at an air ratio of 1.1 with respect to the gas fuel flow rate.
Further, it is assumed that the transition time between the minimum valve opening and the maximum valve opening is set to 30 seconds.
Further, when the combustion load is 0%, the opening degree corresponding to the combustion load of each of the fuel control valve 3 and the air control valve 6 is set to the minimum valve opening degree, and the fuel control valve 3 and the air when the combustion load is 100%. The opening degree corresponding to the combustion load of each control valve 6 is set as the maximum opening degree of each valve.

  When the valve opening degree of each of the fuel control valve 3 and the air control valve 6 is adjusted as described above according to the combustion load, the opening / closing time of the fuel control valve 3 and the air control valve 6 and the combustion load and the set air ratio The relationship is as shown in FIG.

[Another embodiment]
Next, another embodiment will be described.
(A) Fuel control in order to adjust the valve opening of the fuel control valve 3 and the valve opening of the air control valve 6 to a valve opening in which the fuel flow rate is a flow rate corresponding to the combustion load and the flow rate ratio is the set flow rate ratio. The control mode for controlling the valve drive unit 3d of the valve 3 and the valve drive unit 6d of the air control valve 6 is the control mode illustrated in the above embodiment, that is, the transition between the minimum valve opening and the maximum valve opening. The valve opening changing speed is determined for each of the fuel control valve 3 and the air control valve 6 so that the time is the same for the fuel control valve 3 and the air control valve 6. It is not limited to the control form which controls the valve drive part 3d of the fuel control valve 3 and the valve drive part 6d of the air control valve 6 so that it may operate for the same time with the valve opening change speed defined about each.
For example, the valve opening changing speeds of the fuel control valve 3 and the air control valve 6 are set to be the same even if the opening difference between the minimum valve opening and the maximum valve opening is different. Then, the valve drive unit 3d of the fuel control valve 3 is controlled to adjust the valve opening of the fuel control valve 3 from the current valve opening to the combustion load corresponding valve opening at the valve opening changing speed, and the air A control mode in which the valve drive unit 6d of the air control valve 6 is controlled so as to change and adjust the valve opening degree of the control valve 6 from the current valve opening degree to the combustion load corresponding valve opening degree at the valve opening changing speed may be employed.

(B) In the above embodiment, the minimum valve opening and the maximum valve opening of each of the fuel control valve 3 and the air control valve 6 are determined by the difference in opening between the minimum valve opening and the maximum valve opening. 3 and the air control valve 6 are set under different conditions. However, even when the difference between the minimum valve opening and the maximum valve opening is set to be the same between the fuel control valve 3 and the air control valve 6. Good.

(C) In the above embodiment, in the combustion amount adjustment control, the combustion load corresponding valve opening degree of the fuel control valve 3 corresponding to the combustion load is obtained, and further, the valve opening degree of the fuel control valve 3 is changed to the fuel control valve 3. The valve drive part of the fuel control valve 3 is obtained by obtaining the valve opening change time required to change from the current valve opening to the combustion load corresponding valve opening at the corresponding valve opening changing speed for adjusting the combustion amount. 3d and the valve drive part 6d of the air control valve 6 were illustrated for the case of operating the valve opening changing time at the respective combustion amount adjusting drive speeds.
Instead of this, the opening degree of the combustion load corresponding valve of the air control valve 6 corresponding to the combustion load is obtained, and further, the opening degree of the air control valve 6 is adjusted to the opening degree of the combustion amount corresponding to the air control valve 6. The valve opening changing time required for changing the current valve opening from the current valve opening to the combustion load corresponding valve opening at the changing speed is obtained, and the valve driving part 3d of the fuel control valve 3 and the valve driving part of the air control valve 6 are obtained. 6d may be configured to operate for a valve opening changing time at each combustion amount adjusting drive speed.

(D) The number of installed burners 2 is not limited to two as in the above embodiment, and may be three or more.
The number of burners installed may be one.

(E) When setting a plurality of operation modes having different combustion load adjustment ranges, the number of settings is not limited to the two exemplified in the above embodiment, but may be three or more.

(F) The type of the valve in which the relationship between the valve opening degree and the fluid flow rate is linear or substantially linear is not limited to the ball valve exemplified in the above embodiment, and may be various types such as a gate valve. The valve can be adopted.

  As described above, it is possible to provide a fuel air supply amount ratio control device that can appropriately adjust the flow rate ratio between the fuel flow rate and the combustion air flow rate while reducing the cost.

2 Burner 3 Fuel control valve 3d Valve drive unit 6 Air control valve 6d Valve drive unit 7 Control means 12 Mode command means

Claims (5)

A fuel control valve for adjusting the flow rate of fuel supplied to the burner;
An air control valve for adjusting the flow rate of combustion air supplied to the burner;
Control means for controlling the fuel control valve and the air control valve so that the fuel flow rate becomes a flow rate corresponding to the combustion load of the burner and a flow rate ratio between the fuel flow rate and the combustion air flow rate becomes a set flow rate ratio. And a fuel / air supply ratio control device provided with
The fuel control valve has a linear or substantially linear relationship between the valve opening and the fuel flow rate, and includes a valve drive unit that adjusts the valve opening.
The air control valve has a linear or substantially linear relationship between the valve opening and the combustion air flow rate, and includes a valve drive unit that adjusts the valve opening.
The control means converts the valve opening of the fuel control valve and the valve opening of the air control valve to a valve opening at which the fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio. A fuel / air supply amount ratio control device for controlling a valve drive unit of the fuel control valve and a valve drive unit of the air control valve for adjustment. The valve opening changing speed for each of the fuel control valve and the air control valve is between the minimum valve opening when the combustion load is the minimum combustion load and the maximum valve opening when the combustion load is the maximum combustion load. The transition time is determined to be the same speed for the fuel control valve and the air control valve,
The control means operates the fuel control valve and the air control valve at the valve opening change speeds determined for the same time for the same time, and causes the valve drive unit of the fuel control valve and the valve drive unit of the air control valve to operate. By controlling the valve opening of the fuel control valve and the valve opening of the air control valve, the fuel flow rate becomes a flow rate corresponding to the combustion load and the flow rate ratio becomes the set flow rate ratio. The fuel / air supply rate control device according to claim 1, which is adjusted.   The opening difference between the minimum valve opening and the maximum valve opening in the fuel control valve is different from the opening difference between the minimum valve opening and the maximum valve opening in the air control valve. The fuel air supply amount ratio control device according to claim 1.   The fuel / air supply amount ratio control device according to claim 2 or 3, wherein the control means is configured to change and set the transition time. Mode command means is provided for commanding any one operation mode from a plurality of operation modes in which at least one of the minimum combustion load and the maximum combustion load is different and the combustion load adjustment range is different,
Corresponding to each of the plurality of operation modes, the valve opening change speed is determined for each of the fuel control valve and the air control valve,
The control means operates each of the fuel control valve and the air control valve at a valve opening change speed of each of the fuel control valve and the air control valve corresponding to the operation mode commanded by the mode command means. Therefore, the fuel air supply amount ratio control device according to any one of claims 2 to 4, which controls a valve drive unit of the fuel control valve and a valve drive unit of the air control valve.

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