JP2022096200A - Combustion facility - Google Patents

Abstract

To detect a combustion state in a burner, easily make adjustment so that a ratio between combustion air and fuel gas reaches an intended ratio and maintain the good combustion state.SOLUTION: In a combustion facility, air supplied through an air supply pipe 20 and fuel gas supplied through a fuel supply pipe 30 are mixed and burned by a burner 10. An equalizer valve 31 is provided in the fuel supply pipe, and air is supplied from the air supply pipe to the equalizer valve through a connecting pipe 41. The combustion facility includes an oxygen sensor 51 detecting an oxygen concentration in combustion exhaust gas that has burned by the burner. The combustion facility also includes an air ratio control device 50 controlling pressure of air guided from the air supply pipe to the equalizer valve through the connecting pipe on the basis of the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor.SELECTED DRAWING: Figure 1

Description

The present invention relates to a combustion facility in which air supplied through an air supply pipe and fuel gas supplied through a fuel supply pipe are mixed in a desired ratio and burned by a burner. In particular, when the combustion state of the burner is detected and the air supplied to the burner and the fuel gas can be adjusted to the desired ratio by a simple mechanism, the temperature of the air guided to the burner changes, etc. It is also characterized in that the air ratio is adjusted so that the air and the fuel gas are in a desired ratio so that a good combustion state can be easily obtained.

Conventionally, when the air supplied through the air supply pipe and the fuel gas supplied through the fuel supply pipe are mixed and burned by the burner, the air supplied to the burner is used in order to maintain a good combustion state in the burner. Air ratio (air amount / theoretical air amount), which is the ratio of the amount of air supplied by adjusting the ratio to the fuel gas to an appropriate ratio and the theoretical amount of air required for complete combustion of the fuel gas. Is burned to an appropriate (desired) value.

Conventionally, as shown in Patent Document 1, the measured value of the opening degree of the fuel control valve whose relationship between the flow rate coefficient and the opening degree is known, and the combustion air whose relationship between the flow rate coefficient and the opening degree is known. The measured value of the opening degree of the control valve, the measured value of the supply temperature and the supply pressure of the fuel supplied to the burner having a known flow coefficient, and the measured value of the supply temperature and the supply pressure of the air supplied to the burner. The measured value of the furnace temperature and the measured value of the furnace pressure are input to the burner control device, and the burner control device determines the burner amount from the deviation between the measured value of the furnace temperature and the set value. The fuel flow rate that maintains the determined burner combustion amount and the opening degree of the fuel control valve and air control valve corresponding to the air flow rate are calculated by compound throttle calculation so as to maintain the preset air ratio, and fuel control is performed. Adjust the opening degree of each control valve so that the measured value of the opening degree of the valve and the air control valve matches the calculated value of the opening degree of the fuel control valve and the air control valve obtained by the above compound throttle calculation. It has been proposed to control the flow rate.

However, as shown in Patent Document 1, it is very difficult and troublesome to control the flow rates of fuel and air so that the air ratio becomes an appropriate value, and the equipment cost is high. was there.

Further, in Patent Document 2, a fuel gas is provided in a gas combustion device including an air supply line for adjusting the flow rate of air by an air flow rate adjusting mechanism and supplying the burner, and a fuel gas supply line for supplying the fuel gas to the burner. A pressure equalizing valve is provided in the supply line, and pressure equalizing air is guided to the pressure equalizing valve from a pilot pressure acquisition unit provided downstream from the air flow rate adjusting mechanism in the air supply line to produce a premixed gas having a controlled air ratio. It is shown to be burned with a burner.

However, in what is shown in Patent Document 2, there is a problem that the air ratio cannot be kept constant when the temperature of the air or the fuel gas changes and the volumes thereof change.

Further, in Patent Document 3, a fixed orifice is provided in the air flow path that supplies air to the burner, and a variable orifice that can change the opening area is provided in the fuel flow path that supplies fuel to the burner. A first pressure equalizing valve is provided on the upstream side of the variable orifice in the above to make the pressure of the fuel at that position equal to the pressure of the air on the upstream side of the fixed orifice in the air flow path, and is variable in the fuel flow path. A second pressure equalizing valve is provided to make the pressure of the fuel at the position downstream of the orifice equal to the pressure of the air downstream of the fixed orifice in the air flow path, and the temperature of the combustion air in the air flow path is detected. A burner combustion device is shown in which an air temperature detector is provided, and the opening area of the variable orifice is controlled by a control device according to the temperature detected by the air temperature detector.

Here, in the burner combustion device shown in Patent Document 3, the opening area of the variable orifice is controlled by the control device according to the temperature of the air in the air flow path detected by the air temperature detector, whereby air is used. The ratio is kept constant, but in this case, two pressure equalizing valves and a variable orifice are provided between them, and the opening of the variable orifice is based on the temperature of the air in the air flow path detected by the air temperature detector. It is necessary to control the area, the structure of the device is complicated, the equipment cost is high, and the control is also complicated.

Japanese Patent No. 4234309 Japanese Unexamined Patent Publication No. 2010-230279 Japanese Unexamined Patent Publication No. 2012-189299

The present invention solves the above-mentioned problems in a combustion facility in which air supplied through an air supply pipe and fuel gas supplied through a fuel supply pipe are mixed in a desired ratio and burned by a burner. The task is to do.

That is, the present invention makes it possible to adjust the air supplied to the burner and the fuel gas in a desired ratio by a simple mechanism in the above-mentioned combustion equipment, and the temperature of the air guided to the burner changes. Even in such cases, it is an object to adjust the air ratio so that the air and the fuel gas have a desired ratio so that a good combustion state can be easily obtained.

In the combustion equipment according to the present invention, in order to solve the above-mentioned problems, the air supplied through the air supply pipe and the fuel gas supplied through the fuel supply pipe are mixed in a desired ratio. In the combustion equipment burned by the burner, a pressure equalizing valve is provided in the fuel supply pipe, and air is guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe, and in the combustion exhaust gas after being burned by the burner. An oxygen sensor is provided to detect the oxygen concentration in the air, and the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe is controlled based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor. An air ratio control device was provided.

Then, in the combustion equipment of the present invention, the oxygen concentration in the combustion exhaust gas after being burned by the burner as described above is detected by the oxygen sensor, and the air is based on the detected oxygen concentration in the combustion exhaust gas. The ratio control device controls the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe, and the amount of air supplied to the burner through the air supply pipe and the amount of fuel gas supplied through the fuel supply pipe. And adjust.

By doing so, even when the temperature of the air supplied from the air supply pipe to the burner changes, the control is performed based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor, so that the air or fuel gas Even if the temperature of the burner changes, the amount of air supplied to the burner and the amount of fuel gas can be easily adjusted to an appropriate amount.

Here, in the combustion equipment of the present invention, the air ratio control device adjusts the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe, and the air supplied to the burner through the air supply pipe. In order to control the amount of air and the amount of fuel gas supplied through the fuel supply pipe, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe that supplies air to the burner. A first pressure guiding tube provided at a position on the upstream side of the flow control valve, a second pressure guiding tube provided at a position on the downstream side of the flow control valve, and a third pressure guiding tube for guiding air to the pressure equalizing valve are three-way. It is possible to control the pressure of the air guided to the pressure equalizing valve through the third pressure guiding tube by connecting to the adjusting valve and adjusting the three-way adjusting valve by the air ratio control device.

Further, in the combustion equipment of the present invention, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe that supplies air to the burner, and air is supplied to a position on the upstream side of the flow control valve. A pressure guiding tube leading to the pressure equalizing valve is provided, and a pressure adjusting valve for adjusting the pressure of air guided to the pressure equalizing valve through the pressure guiding tube is provided at a position in the middle of the pressure guiding tube, and the pressure adjusting is performed by the air ratio control device. The valve can be adjusted to control the pressure of air guided through the pressure guiding tube to the pressure equalizing valve. In the pressure regulating valve, a part of the air guided by the pressure guiding tube can be exhausted to adjust the pressure of the air guided to the pressure equalizing valve through the pressure guiding tube.

Further, in the combustion equipment of the present invention, a heating device for heating the air is provided at a position in the middle of the air supply pipe for supplying the air to the burner, and the air heated by the heating device is used as the burner. It can be supplied and burned.

Here, even when the air supplied to the burner is heated by the heating device as described above, in the combustion equipment of the present invention, the oxygen concentration in the combustion exhaust gas after being burned by the burner as described above is oxygen. Based on the oxygen concentration in the combustion exhaust gas detected by the sensor, the air ratio control device controls the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe to the burner. Since the amount of air supplied through the air supply pipe and the amount of fuel gas supplied through the fuel supply pipe are adjusted, the desired ratio of air and fuel gas is obtained even if the temperature of the air or fuel gas changes. It will be easy to adjust to.

In the combustion equipment of the present invention, the oxygen concentration in the combustion exhaust gas after being burned by the burner as described above is detected by the oxygen sensor, and the air ratio control is performed based on the detected oxygen concentration in the combustion exhaust gas. The device controls the pressure of the air guided from the air supply pipe through the pressure guiding pipe to the pressure equalizing valve to control the amount of air supplied to the burner through the air supply pipe and the amount of fuel gas supplied through the fuel supply pipe. Since it is adjusted, it is easy to adjust the amount of air supplied to the burner and the amount of fuel gas to an appropriate amount even if the temperature of the air supplied from the air supply pipe to the burner changes. You will be able to do it.

As a result, in the combustion equipment of the present invention, as compared with the conventional combustion equipment, the air supplied to the burner and the fuel gas can be adjusted to a desired ratio by a simple mechanism, and the combustion equipment is guided to the burner. Even when the temperature of the air changes, the air ratio is adjusted so that the ratio of the air and the fuel gas becomes a desired ratio, so that a good combustion state can be easily obtained.

In the combustion equipment according to the first embodiment of the present invention, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe for supplying air to the burner, and is provided at a position on the upstream side of the flow control valve. The first pressure guiding tube, the second pressure guiding tube provided on the downstream side of the flow control valve, and the third pressure guiding tube that guides air to the pressure equalizing valve are connected to the three-way adjusting valve, and the above-mentioned three-way control device is used. It is schematic explanatory drawing which showed the state which adjusted the adjustment valve, and controlled the pressure of the air guided to the pressure equalizing valve provided in the fuel supply pipe through the 3rd pressure guide pipe. In the combustion equipment according to the first embodiment, in providing a heating device for heating the air in the air supply pipe that guides the air to the burner, (A) is a state in which the heating device is provided at a position upstream of the flow control valve. (B) is a schematic explanatory view showing a state in which the heating device is provided at a position on the downstream side of the flow rate control valve. In the combustion equipment according to the second embodiment of the present invention, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe for supplying air to the burner, and air is supplied to a position on the upstream side of the flow control valve. A pressure guiding tube leading to the pressure equalizing valve is provided, and a pressure adjusting valve for adjusting the pressure of air guided to the pressure equalizing valve through the pressure guiding tube is provided at a position in the middle of the pressure guiding tube. It is schematic explanatory drawing which showed the state which adjusted and controlled the pressure of the air which is guided to the said pressure equalizing valve through the said pressure guide tube.

Hereinafter, the combustion equipment according to the embodiment of the present invention will be specifically described with reference to the accompanying drawings. The combustion equipment according to the present invention is not limited to the one shown in the following embodiment, and can be appropriately modified and implemented without changing the gist of the invention.

(Embodiment 1)
In the combustion equipment according to the first embodiment, as shown in FIG. 1, the burner 10 is supplied with air through the air supply pipe 20 and fuel gas is supplied through the fuel supply pipe 30, and the air is supplied in this way. The fuel gas is mixed in a desired ratio and burned in the furnace 1 by the burner 10. In this embodiment, air and fuel gas are mixed and burned in the furnace 1 by the burner 10. However, the place of combustion is not particularly limited and is not shown, but is radiant. It is also possible to burn in a tube.

Further, in the first embodiment, a flow rate control valve 21 for controlling the flow rate of the air supplied to the burner 10 is provided at a position in the middle of the air supply pipe 20, while a position in the middle of the fuel supply pipe 30 is provided. Is provided with a pressure equalizing valve 31.

Here, in a fully open state where the flow rate control valve 21 provided in the middle of the air supply pipe 20 does not limit the flow rate of the air supplied to the burner 10 through the air supply pipe 20, it is upstream of the flow rate control valve 21. The air pressure Pa1 on the side and the air pressure Pa2 on the downstream side of the flow control valve 21 match (Pa1 = Pa2), but the flow rate of air supplied to the burner 10 through the air supply pipe 20 by the flow control valve 21. When is reduced, the air pressure Pa2 on the downstream side of the flow control valve 21 is lower than the air pressure Pa1 on the upstream side of the flow control valve 21 (Pa1> Pa2).

Then, in the first embodiment, in the air supply pipe 20, a first pressure guiding pipe 41a is provided at a position on the upstream side of the flow rate control valve 21, and the first pressure guiding pipe 41a is electrically adjusted in three directions. It is connected to the first port 42a of the valve 42, and the air of the pressure Pa1 is sent to the first port 42a through the first pressure guiding pipe 41a, and the second guide is located downstream of the flow control valve 21. A pressure tube 41b is provided, the second pressure guiding tube 41b is connected to the second port 42b of the three-way adjusting valve 42, and air of pressure Pa2 is sent to the second port 42b through the second pressure guiding tube 41b. A three-way pressure guiding pipe 41c is provided between the third port 42c of the three-way adjusting valve 42 and the pressure equalizing valve 31, and air adjusted to a predetermined pressure Pa3 by the three-way adjusting valve 42 is sent to the pressure equalizing valve 31. I try to send it.

At this time, since the downstream of the third pressure guiding tube 41c is closed by the diagram (not shown) inside the pressure equalizing valve 31, air does not flow and only the pressure is transmitted.

In the three-way adjusting valve 42, the third port 42c communicates with the first port 42a and the second port 42b, and the internal valve plate (not shown) can be stopped at an intermediate position. Thereby, the ratio of the opening degree (0 to 100%) of the first port 42a and the opening degree (100 to 0%) of the second port 42b can be changed with respect to the opening degree (100%) of the third port 42c.

Here, when air adjusted to a predetermined pressure Pa3 is sent from the third pressure guiding pipe 41c to the pressure equalizing valve 31, the pressure Pg1 of the fuel gas sent to the pressure equalizing valve 31 through the fuel supply pipe 30 is said. The pressure Pg2 of the fuel gas, which is equalized by the pressure equalizing valve 31 and sent to the burner 10 through the fuel supply pipe 30 on the downstream side of the pressure equalizing valve 31, is the pressure sent from the third pressure guiding pipe 41c to the pressure equalizing valve 31. The pressure becomes the same as Pa3 (Pg2 = Pa3).

Further, in the first embodiment, an oxygen sensor 51 for detecting the oxygen concentration in the combustion exhaust gas after mixing air and fuel gas as described above and burning them in the furnace 1 by the burner 10 is provided. The oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 is output to the air ratio control device 50.

Then, in the first embodiment, the pressure Pa2 of the air sent to the burner 10 through the air supply pipe 20 and the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 are adjusted and sent to the burner 10. In controlling the air ratio to an appropriate value, the three-way control valve 42 is controlled by the air ratio control device 50 based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51, and the three-way control valve 42 is controlled. The pressure Pa3 of the air guided from the third port 42c connected to the first port 42a and the second port 42b to the pressure equalizing valve 31 through the third pressure guiding pipe 41c is adjusted and sent to the burner 10 through the fuel supply pipe 30. The pressure Pg2 of the fuel gas to be generated is adjusted. The relationship between the pressure Pa1, the pressure Pa2, the pressure Pa3, and the pressure Pg2 is Pa1 ≧ Pa3 (= Pg2) ≧ Pa2, including the case where the flow rate is not restricted by the flow rate control valve 21. become.

As the action of the three-way adjusting valve 42, the pressure of Pa3 can be changed by adjusting the mixing ratio of Pa1 having a high pressure and Pa2 having a low pressure, and the pressure can be adjusted with a simple structure.

Here, when the ratio of the air sent to the burner 10 to the fuel gas is changed so as to lower the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51, the air ratio is lowered. The three-way control valve 42 is controlled by the air ratio control device 50, and the ratio of guiding the air of the pressure Pa1 through the first pressure guiding tube 41a to the third pressure guiding tube 41c through the first port 42a to the third port 42c is increased. On the other hand, the ratio of guiding the air of the pressure Pa2 through the second pressure guiding tube 41b from the second port 42b to the third pressure guiding tube 41c through the third port 42c is reduced, and the above-mentioned is performed through the third pressure guiding tube 41c. The pressure Pa3 of the air sent to the pressure equalizing valve 31 is increased, thereby increasing the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30, and increasing the proportion of the fuel gas sent to the burner 10.

On the other hand, when the ratio of the air sent to the burner 10 to the fuel gas is changed to increase the air ratio so that the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 becomes high, the air is described above. The three-way control valve 42 is controlled by the ratio control device 50 to reduce the ratio of air of pressure Pa1 being guided from the first port 42a to the third pressure guiding tube 41c through the third port 42c through the first pressure guiding tube 41a. On the other hand, the ratio of guiding the air of the pressure Pa2 through the second pressure guiding tube 41b from the second port 42b to the third pressure guiding tube 41c through the third port 42c is increased, and the leveling is performed through the third pressure guiding tube 41c. The pressure Pa3 of the air sent to the pressure valve 31 is lowered, thereby lowering the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30, and the ratio of the fuel gas sent to the burner 10 is reduced.

Therefore, in the combustion equipment of the first embodiment, the amount of air supplied to the burner 10 and the amount of fuel gas as described above are determined based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51. It will be easy to adjust to the appropriate amount.

Further, in the combustion equipment of the first embodiment, in order to efficiently burn the fuel gas, as shown in FIGS. 2A and 2B, the flow rate in the air supply pipe 20 for supplying air to the burner 10 is described above. A heating device 23 such as a heat exchanger can be provided at a position on the upstream side or the downstream side of the control valve 21 so that the air supplied to the burner 10 can be heated by the heating device 23.

In this case, the volume of air increases due to heating by the heating device 23, and the amount of oxygen per volume decreases. Therefore, the amount of oxygen supplied to the burner 10 in the same volume of the heated air is smaller than that in the case of supplying unheated air to the burner 10. Then, the oxygen concentration per volume in the combustion exhaust gas decreases (that is, the air ratio decreases).

However, in the combustion equipment of the first embodiment, the amount of air supplied to the burner 10 and the amount of fuel gas are adjusted based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 as described above.

For example, when the air ratio decreases as described above, the pressure of the fuel gas is lowered by adjusting the three-way control valve 42 to reduce the amount of fuel gas supplied to the burner 10 and try to increase the air ratio. The air ratio is kept constant.

As a result, even if the air expands and the volume increases, the air ratio is adjusted so that the air and the fuel gas have an appropriate ratio, and a good combustion state can be easily obtained.

(Embodiment 2)
In the combustion equipment according to the second embodiment, as shown in FIG. 3, as in the combustion equipment according to the first embodiment, air is supplied to the burner 10 through the air supply pipe 20 and fuel gas is supplied through the fuel supply pipe 30. Is supplied, and the air and fuel gas thus supplied are mixed in a desired ratio and burned in the furnace 1 by the burner 10.

Further, also in the second embodiment, the flow control valve 21 for controlling the flow rate of the air supplied to the burner 10 is provided at the position in the middle of the air supply pipe 20, while the position in the middle of the fuel supply pipe 30. A pressure equalizing valve 31 is provided in the above, and as in the case of the first embodiment, the air supplied to the burner 10 through the air supply pipe 20 by the flow control valve 21 provided in the middle of the air supply pipe 20. In the fully open state where the flow rate is not limited, the air pressure Pa1 on the upstream side of the flow rate control valve 21 and the air pressure Pa2 on the downstream side of the flow rate control valve 21 match (Pa1 = Pa2), but the flow rate control valve. When the flow rate of the air supplied to the burner 10 through the air supply pipe 20 is reduced by 21, the air on the downstream side of the flow control valve 21 is larger than the air pressure Pa1 on the upstream side of the flow control valve 21. Pressure Pa2 becomes low (Pa1> Pa2).

Then, in the second embodiment, a pressure guiding pipe 41 for sending air from the air supply pipe 20 to the pressure equalizing valve 31 is provided at a position on the upstream side of the flow control valve 21 in the air supply pipe 20. At the same time, an exhaust pipe 44 provided with a pressure adjusting valve 43 is provided at a position in the middle of sending the air of pressure Pa1 to the pressure equalizing valve 31 by the pressure guiding pipe 41, and the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41 is provided. The amount of air exhausted through the exhaust pipe 44 is adjusted by the pressure adjusting valve 43 to control the pressure Pa3 of the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41. In this way, the pressure Pg1 of the fuel gas sent to the pressure equalizing valve 31 through the fuel supply pipe 30 is equalized by the pressure equalizing valve 31, and the burner 10 is passed through the fuel supply pipe 30 on the downstream side of the pressure equalizing valve 31. The pressure Pg2 of the fuel gas sent to is the same as the pressure Pa3 (Pg2 = Pa3) sent from the third pressure guiding tube 41c to the pressure equalizing valve 31.

Further, also in the second embodiment, an oxygen sensor 51 for detecting the oxygen concentration in the combustion exhaust gas after the air and the fuel gas are mixed and burned in the furnace 1 by the burner 10 as described above is provided. The oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 is output to the air ratio control device 50.

Then, in the second embodiment, the pressure Pa2 of the air sent to the burner 10 through the air supply pipe 20 and the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 are adjusted and sent to the burner 10. In controlling the air ratio to an appropriate value, the pressure control valve 43 is controlled by the air ratio control device 50 based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51. The amount of air exhausted through the exhaust pipe 44 is adjusted to control the pressure Pa3 sent to the pressure equalizing valve 31, and the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 is adjusted. The relationship between the pressure Pa1, the pressure Pa2, the pressure Pa3, and the pressure Pg2 is Pa1 ≧ Pa3 (= Pg2) ≧ Pa2, including the case where the flow rate is not restricted by the flow rate control valve 21. become.

As the action of the three-way control valve 42, the pressure of Pa3 can be changed by adjusting the amount of releasing a part of the pressure Pa1 of the air supplied at a constant pressure, and the pressure can be adjusted with a simple structure. can.

Here, when the ratio of the air sent to the burner 10 to the fuel gas is changed to lower the air ratio so that the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 is lowered, the above-mentioned The pressure adjusting valve 43 is controlled by the air ratio control device 50 to reduce the amount of air exhausted through the exhaust pipe 44, and the pressure Pa3 of the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41. As a result, the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 is increased, and the proportion of the fuel gas sent to the burner 10 is increased.

On the other hand, when the ratio of the air sent to the burner 10 to the fuel gas is changed to increase the air ratio so that the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 becomes high, the air is described above. The pressure control valve 43 is controlled by the ratio control device 50 to increase the amount of air exhausted through the exhaust pipe 44, and the pressure Pa3 of the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41 is increased. Lowering the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 lowers the ratio of the fuel gas sent to the burner 10.

Therefore, also in the combustion equipment of the second embodiment, as in the combustion equipment of the first embodiment, the burner 10 is used as described above based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51. It becomes easy to adjust the amount of air to be supplied and the amount of fuel gas to an appropriate amount.

Further, although not shown in the combustion equipment of the second embodiment, the air supply pipe 20 that supplies air to the burner 10 in order to efficiently burn the fuel gas is similar to the combustion equipment of the first embodiment. A heating device 23 such as a heat exchanger can be provided at a position on the upstream side or the downstream side of the flow control valve 21 in the above, and the air supplied to the burner 10 can be heated by the heating device 23.

In this case, the volume of air increases due to heating by the heating device 23, and the amount of oxygen per volume decreases. Therefore, the amount of oxygen supplied to the burner 10 in the same volume of the heated air is smaller than that in the case of supplying unheated air to the burner 10. Then, the oxygen concentration per volume in the combustion exhaust gas decreases (that is, the air ratio decreases).

However, in the combustion equipment of the second embodiment, the amount of air supplied to the burner 10 and the amount of fuel gas are adjusted based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 as described above.

For example, when the air ratio decreases as described above, the pressure of the fuel gas is lowered by adjusting the three-way control valve 42 to reduce the amount of fuel gas supplied to the burner 10 and try to increase the air ratio. The air ratio is kept constant.

As a result, even if the air expands and the volume increases, the air ratio is adjusted so that the air and the fuel gas have an appropriate ratio, and a good combustion state can be easily obtained.

1: Furnace 10: Burner 20: Air supply pipe 21: Flow control valve 23: Heating device 30: Fuel supply pipe 31: Pressure equalizing valve 41: Pressure guiding pipe 41a: First pressure guiding pipe 41b: Second pressure guiding pipe 41c: Third guiding Pressure pipe 42: Three-way control valve 42a: First port 42b: Second port 42c: Third port 43: Pressure control valve 44: Exhaust pipe 50: Air ratio control device 51: Oxygen sensor

In the combustion equipment according to the present invention, in order to solve the above-mentioned problems, the air supplied through the air supply pipe and the fuel gas supplied through the fuel supply pipe are mixed in a desired ratio. In a combustion facility that burns with a burner, a pressure equalizing valve is provided in the fuel supply pipe, and air is guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe, and in the combustion exhaust gas after being burned by the burner. An oxygen sensor is provided to detect the oxygen concentration in the air, and the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe is controlled based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor. An air ratio control device is provided, and a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe that supplies air to the burner, and is located upstream of the flow control valve. The first pressure guiding tube provided, the second pressure guiding tube provided at a position on the downstream side of the flow control valve, and the third pressure guiding tube that guides air to the pressure equalizing valve are connected to the three-way adjusting valve, and the air ratio is described above. The three-way regulating valve was adjusted by a control device to control the pressure of air guided to the pressure equalizing valve through the third pressure guiding tube .

Here, in the combustion equipment of the present invention, the air ratio control device adjusts the pressure of the air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe, and supplies the air to the burner through the air supply pipe. In controlling the amount of air and the amount of fuel gas supplied through the fuel supply pipe, the flow rate of air is controlled at a position in the middle of the air supply pipe that supplies air to the burner as described above. A flow control valve is provided, and a first pressure guiding tube provided at a position on the upstream side of the flow control valve, a second pressure guiding tube provided at a position on the downstream side of the flow control valve, and a second pressure equalizing valve for guiding air to the pressure equalizing valve. The three-way control valve is connected to the three-way control valve, and the three-way control valve is adjusted by the air ratio control device to control the pressure of the air guided to the pressure equalizing valve through the third pressure guide tube. I made it .

In the combustion equipment according to the first embodiment of the present invention, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe for supplying air to the burner, and is provided at a position on the upstream side of the flow control valve. The first pressure guiding tube, the second pressure guiding tube provided on the downstream side of the flow control valve, and the third pressure guiding tube that guides air to the pressure equalizing valve are connected to the three-way adjusting valve, and the above-mentioned three-way control device is used. It is schematic explanatory drawing which showed the state which adjusted the adjustment valve, and controlled the pressure of the air guided to the pressure equalizing valve provided in the fuel supply pipe through the 3rd pressure guide pipe. In the combustion equipment according to the first embodiment, in providing a heating device for heating the air in the air supply pipe that guides the air to the burner, (A) is a state in which the heating device is provided at a position upstream of the flow control valve. (B) is a schematic explanatory view showing a state in which the heating device is provided at a position on the downstream side of the flow rate control valve. In the combustion equipment according to the reference embodiment of the present invention, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe for supplying air to the burner, and the air is leveled at a position on the upstream side of the flow control valve. A pressure guiding tube leading to the pressure valve is provided, and a pressure adjusting valve for adjusting the pressure of the air guided to the pressure equalizing valve through the pressure guiding tube is provided at a position in the middle of the pressure guiding tube, and the pressure adjusting valve is adjusted by the air ratio control device. It is a schematic explanatory view which showed the state which controlled the pressure of the air which is guided to the said pressure equalizing valve through the said pressure guide tube.

( Reference form )
Also in the combustion equipment in the reference embodiment , as shown in FIG. 3, as in the combustion equipment in the first embodiment, air is supplied to the burner 10 through the air supply pipe 20 and fuel gas is supplied through the fuel supply pipe 30. It is supplied, and the air supplied in this way and the fuel gas are mixed in a desired ratio and burned in the furnace 1 by the burner 10.

Further, also in this reference embodiment , a flow control valve 21 for controlling the flow rate of the air supplied to the burner 10 is provided at a position in the middle of the air supply pipe 20, while at a position in the middle of the fuel supply pipe 30. A pressure equalizing valve 31 is provided, and as in the case of the first embodiment, the flow rate of air supplied to the burner 10 through the air supply pipe 20 by the flow control valve 21 provided in the middle of the air supply pipe 20. In the fully open state, the air pressure Pa1 on the upstream side of the flow control valve 21 and the air pressure Pa2 on the downstream side of the flow control valve 21 match (Pa1 = Pa2), but the flow control valve 21 When the flow rate of the air supplied to the burner 10 through the air supply pipe 20 is reduced, the air pressure on the downstream side of the flow control valve 21 is higher than the air pressure Pa1 on the upstream side of the flow control valve 21. The pressure Pa2 becomes low (Pa1> Pa2).

In this reference embodiment , a pressure guiding tube 41 that sends air from the air supply pipe 20 to the pressure equalizing valve 31 is provided at a position upstream of the flow control valve 21 in the air supply pipe 20. An exhaust pipe 44 provided with a pressure adjusting valve 43 is provided at a position in the middle of sending the air of pressure Pa1 to the pressure equalizing valve 31 by the pressure guiding pipe 41, and the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41 is provided. The amount of air exhausted through the exhaust pipe 44 is adjusted by the pressure adjusting valve 43 to control the pressure Pa3 of the air sent to the pressure equalizing valve 31 through the pressure guiding pipe 41. In this way, the pressure Pg1 of the fuel gas sent to the pressure equalizing valve 31 through the fuel supply pipe 30 is equalized by the pressure equalizing valve 31, and the burner 10 is passed through the fuel supply pipe 30 on the downstream side of the pressure equalizing valve 31. The pressure Pg2 of the fuel gas sent to is the same as the pressure Pa3 (Pg2 = Pa3) sent from the third pressure guiding tube 41c to the pressure equalizing valve 31.

Further, also in this reference embodiment , an oxygen sensor 51 for detecting the oxygen concentration in the combustion exhaust gas after mixing air and fuel gas and burning them in the furnace 1 by the burner 10 is provided as described above, and the oxygen is provided. The oxygen concentration in the combustion exhaust gas detected by the sensor 51 is output to the air ratio control device 50.

Then, in this reference embodiment , the pressure Pa2 of the air sent to the burner 10 through the air supply pipe 20 and the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 are adjusted, and the air sent to the burner 10 is adjusted. In controlling the ratio to an appropriate value, the pressure control valve 43 is controlled by the air ratio control device 50 based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51, and the pressure control valve 43 is controlled. The pressure Pa3 sent to the pressure equalizing valve 31 is controlled by adjusting the amount of air exhausted through the exhaust pipe 44 of the above, and the pressure Pg2 of the fuel gas sent to the burner 10 through the fuel supply pipe 30 is adjusted. The relationship between the pressure Pa1, the pressure Pa2, the pressure Pa3, and the pressure Pg2 is Pa1 ≧ Pa3 (= Pg2) ≧ Pa2, including the case where the flow rate is not restricted by the flow rate control valve 21. become.

Therefore, also in the combustion equipment of this reference embodiment , similarly to the combustion equipment of the first embodiment, the fuel is supplied to the burner 10 as described above based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51. It becomes easy to adjust the amount of air to be made and the amount of fuel gas to an appropriate amount.

Further, in the combustion equipment of this reference embodiment , although not shown, in the air supply pipe 20 that supplies air to the burner 10 in order to efficiently burn the fuel gas as in the combustion equipment of the first embodiment. A heating device 23 such as a heat exchanger can be provided at a position on the upstream side or the downstream side of the flow control valve 21 so that the air supplied to the burner 10 can be heated by the heating device 23.

However, in the combustion equipment of the reference embodiment , the amount of air supplied to the burner 10 and the amount of fuel gas are adjusted based on the oxygen concentration in the combustion exhaust gas detected by the oxygen sensor 51 as described above.

Claims (5)

In a combustion facility in which air supplied through an air supply pipe and fuel gas supplied through a fuel supply pipe are mixed in a desired ratio and burned by a burner, a pressure equalizing valve is provided in the fuel supply pipe. The pressure equalizing valve is provided with an oxygen sensor that guides air from the air supply pipe through the pressure guiding pipe and detects the oxygen concentration in the combustion exhaust gas after being burned by the burner, and is detected by the oxygen sensor. A combustion facility provided with an air ratio control device that controls the pressure of air guided from the air supply pipe to the pressure equalizing valve through the pressure guiding pipe based on the oxygen concentration in the combustion exhaust gas. In the combustion equipment according to claim 1, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe that supplies air to the burner, and is provided at a position on the upstream side of the flow control valve. The first pressure guiding tube, the second pressure guiding tube provided at a position on the downstream side of the flow control valve, and the third pressure guiding tube for guiding air to the pressure equalizing valve are connected to the three-way adjusting valve, and the air ratio control device is described. A combustion facility characterized in that the pressure of air guided to the pressure equalizing valve through the third pressure guiding tube is controlled by adjusting the three-way adjusting valve. In the combustion equipment according to claim 1, a flow control valve for controlling the flow rate of air is provided at a position in the middle of the air supply pipe that supplies air to the burner, and air is supplied to a position on the upstream side of the flow control valve. A pressure guiding tube leading to the pressure equalizing valve is provided, and a pressure adjusting valve for adjusting the pressure of air guided to the pressure equalizing valve through the pressure guiding tube is provided at a position in the middle of the pressure guiding tube. A combustion facility characterized in that a pressure regulating valve is adjusted to control the pressure of air guided to the pressure equalizing valve through the pressure guiding tube. In the combustion equipment according to claim 3, the pressure regulating valve is characterized in that a part of the air guided by the pressure guiding tube is exhausted to adjust the pressure of the air guided to the pressure equalizing valve through the pressure guiding tube. Combustion equipment. The combustion equipment according to any one of claims 1 to 4, characterized in that a heating device for heating the air is provided at a position in the middle of the air supply pipe for supplying air to the burner. Combustion equipment.

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