JPH08261445A - Igniting and burning method of gas burner - Google Patents

Abstract

PURPOSE: To provide igniting and burning method of a gas burner, which is capable of restraining the generation of the lift of flame after igniting the gas burner due to ignition or switching of the gas burner. CONSTITUTION: Immediately after igniting gas burners 4a, 4b, received in a combustion chamber 5, the supplying amount of combustion air and fuel gas is controlled so that the rate of supplying amount of fuel gas to the supplying amount of combustion air becomes larger than the rate of the objective amount of fuel gas to the objective amount of combustion air corresponding to the necessary amount of combustion of the gas burners 4a, 4b. Thereafter, the supplying amount of combustion air and fuel gas is controlled so that the rate of supplying amount of fuel gas to the supplying amount of combustion air coincides gradually with the rate of objective amount of fuel gas to the objective amount of combustion air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition and combustion method for a gas burner, and more particularly to an ignition and combustion method suitable for a low NOx gas burner with reduced nitrogen oxides.

[0002]

2. Description of the Related Art For example, in a gas combustion apparatus such as a gas water heater, a combustion fan is supplied to a gas burner housed in a combustion chamber so that a target amount of combustion air corresponding to the required combustion amount is supplied from the combustion fan. It is generally known to control and supply the target amount of fuel gas corresponding to the required combustion amount to the gas burner via an electromagnetic proportional valve. In this case, for example, in the case of a so-called fan preceding type, by driving the combustion fan at a target rotation speed corresponding to the required combustion amount, a target amount of combustion air corresponding to the required combustion amount is supplied to the gas burner. To the target amount corresponding to the required combustion amount indirectly by controlling the opening of the electromagnetic proportional valve according to the rotation speed of the combustion fan. .

Further, in this type of gas combustion equipment, a plurality of gas burners having different combustion capacities are arranged in parallel in the combustion chamber, and the gas burners are selectively switched and burned in accordance with the required combustion amount. It is also known to do so. In this case, when switching from one gas burner to another gas burner, the fuel gas supply amount is temporarily increased to supply the fuel gas to both gas burners, and in this state, the burning gas burner fires the other gas burner. Let's move
Ignite the other gas burner.

On the other hand, in the gas burner of this type of gas combustion equipment, in recent years, nitrogen oxides (N
It is desired to reduce the amount of Ox), and therefore, as a gas burner aiming at such reduction of NOx, for example, Japanese Patent Laid-Open No.
A gas burner having a structure proposed by the applicant of the present application is known from Japanese Patent Publication No. 263505. This gas burner has a pair of second flame holes formed on both sides of a flat first flame hole. In the first flame hole, a fuel gas leaner than the stoichiometric air-fuel ratio is used to generate a mixture with combustion air. In addition to burning (burning in a so-called air-rich state), in the second flame holes on both sides thereof, a mixture gas with combustion air is burned with a fuel gas richer than the theoretical air-fuel ratio (burning in a so-called gas-rich state). It was done like this. In this case, the first
And the air-fuel ratio of the air-fuel mixture to be burned in the second flame hole is appropriately set by the suction hole for the air-fuel mixture provided corresponding to each flame hole, the size of the nozzle for injecting the fuel gas into the suction hole, and the like. By doing so, the air-rich or gas-rich state as described above is adjusted.

By the way, in such a gas combustion apparatus, when the gas burner is ignited at the start of combustion, or when the combustion capacity of the gas burner is switched to ignite and burn the gas burner having a new combustion capacity, Conventionally, at least immediately after ignition of the gas burner, the amounts of both the combustion air and the fuel gas supplied to the gas burner are controlled to target amounts corresponding to the required combustion amount.

However, according to various studies by the inventors of the present application, when the supply amounts of the combustion air and the fuel gas are controlled as described above, the lift of the flame is likely to occur immediately after the ignition of the gas burner. It was found that in the low NOx gas burner, the tendency was remarkable in the first flame hole.

The cause of the lift as described above is considered as follows. That is, in the gas combustion equipment as described above, the target amount of combustion air and fuel gas corresponding to the required combustion amount is basically good combustion when continuous combustion of the gas burner is performed. Is determined to be. On the other hand, immediately after ignition of the gas burner, since the temperature of the gas burner is still low, the passage resistance is small and the combustion speed of the air-fuel mixture in the flame holes of the gas burner tends to be slower than the ejection speed. It is thought to occur easily. Especially in the above-mentioned low NOx gas burner, it is considered that this tendency becomes remarkable because the air-fuel mixture is burned in the air-rich state at the first flame hole.

[0008]

SUMMARY OF THE INVENTION In view of the above background, it is an object of the present invention to provide an ignition and combustion method for a gas burner capable of suppressing the generation of a lift of a flame after ignition of the gas burner due to ignition or switching of the gas burner. And

[0009]

In order to achieve the above object, the first aspect of the present invention is to provide a gas burner housed in a combustion chamber with a target amount of combustion air and fuel gas corresponding to the required combustion amount. In the ignition and combustion method of a gas burner for controlling the supply amounts of the combustion air and the fuel gas so as to supply the gas burner, at least immediately after the ignition of the gas burner, the fuel gas with respect to the supply amount of the combustion air is supplied. Control step for controlling the supply amounts of the combustion air and the fuel gas such that the ratio of the supply amount of the combustion air is larger than the ratio of the target amount of the fuel gas to the target amount of the combustion air corresponding to the required combustion amount. And thereafter, the fuel gas is supplied so that the ratio of the fuel gas supply amount to the combustion air supply amount gradually matches the fuel gas target amount to the combustion air supply amount. Characterized by comprising a second control step of controlling the supply amount of use air and fuel gas.

Further, in the first control step, the supply amount of the combustion air is controlled to the target amount at least immediately after the ignition of the gas burner, and the supply amount of the fuel gas is adjusted at least immediately after the ignition of the gas burner. The second control step controls the supply amount of the combustion air to the target amount while gradually changing the supply amount of the fuel gas toward the target amount by controlling the supply amount of the combustion air to be larger than the target amount by a predetermined amount. It is characterized by being busy.

Alternatively, the first control step controls the supply amount of the fuel gas to a target amount thereof at least immediately after the ignition of the gas burner, and controls the supply amount of the combustion air at least immediately after the ignition of the gas burner. The second control step controls the supply amount of the fuel gas to the target amount while gradually changing the supply amount of the combustion air toward the target amount by controlling the supply amount of the fuel gas to be smaller than the target amount by a predetermined amount. It is characterized by being busy.

In the second aspect of the present invention, at least one gas burner is selected from a plurality of gas burners arranged in parallel in the combustion chamber and having different combustion capacities, and the required combustion amount for the gas burner is selected. A step of controlling the supply amounts of the combustion air and the fuel gas so as to supply a target amount of the combustion air and the fuel gas, and performing the combustion of the gas burner; and, depending on the required combustion amount during the combustion of the gas burner. Another gas burner is newly selected to switch the gas burner to be burned, the other gas burner is ignited, and the target amount of combustion air and fuel gas corresponding to the required combustion amount is supplied to the other gas burner. In a method for igniting and burning a gas burner, the method comprising controlling the supply amounts of combustion air and fuel gas to burn the other gas burner. At least immediately after ignition of the other gas burner, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is higher than the ratio of the target amount of the fuel gas to the target amount of the combustion air corresponding to the required combustion amount. A first control step of controlling the supply amounts of the combustion air and the fuel gas so as to increase, and thereafter, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is the fuel gas to the target amount of the combustion air. A second control for controlling the supply amounts of the combustion air and the fuel gas so as to gradually match the ratio of the target amount of
And a control step, and the switching of the gas burner temporarily supplies fuel gas to both the gas burner and another gas burner to be newly burned during combustion of at least one gas burner, In this state, the flame is transferred from the burning gas burner to the other gas burner, and the other gas burner is ignited and burned, and thereafter,
It is performed by interrupting the supply of the fuel gas to the burning gas burner while continuing the supply of the fuel gas to the other gas burner, and the first control step transfers the fire to the other gas burner and The feature is that it is performed immediately after another gas burner ignites.

Further, in the first control step, the supply amount of the combustion air is controlled to the target amount at least immediately after the ignition of the other gas burner, and the supply amount of the fuel gas is at least immediately after the ignition of the gas burner. Is controlled to be larger than the target amount by a predetermined amount, and the second control step controls the supply amount of the combustion air toward the target amount while controlling the supply amount of the combustion air to the target amount. It is characterized by gradually changing.

Alternatively, the first control step controls the supply amount of the fuel gas to a target amount at least immediately after the ignition of the other gas burner, and at least immediately after the ignition of the gas burner, the supply amount of the combustion air. Is controlled to be smaller than the target amount by a predetermined amount, and the second control step controls the supply amount of the combustion gas toward the target amount while controlling the supply amount of the fuel gas to the target amount. It is characterized by gradually changing.

Further, in the first and second aspects of the present invention, the gas burner includes a first flame hole and second flame holes formed on both sides of the first flame hole. A gas burner that burns an air-fuel mixture with combustion air with a fuel gas leaner than the stoichiometric air-fuel ratio in the flame holes, and burns a fuel-air mixture with combustion air with a fuel gas richer than the stoichiometric air-fuel ratio in the second flame holes. Is characterized in that.

[0016]

According to the first aspect of the present invention, immediately after ignition of the gas burner, the target of the combustion air is such that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air corresponds to the required combustion amount. Since the supply amounts of the combustion air and the fuel gas are controlled so as to be larger than the ratio of the target amount of the fuel gas to the amount thereof, at this time, the fuel gas is relatively supplied to the amount of the combustion air supplied to the gas burner. The amount of is controlled to be larger than in the normal case. Therefore, it becomes possible to satisfactorily perform combustion of the gas burner even in a low temperature state immediately after ignition of the gas burner. Then, from this state, the combustion air and the fuel gas are supplied so that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air gradually matches the ratio of the target amount of the fuel gas to the target amount of the combustion air. Since the amount is controlled, the ratio of the supply amount of the combustion air and the supply amount of the fuel gas is controlled to be an appropriate ratio corresponding to the required combustion amount while adapting to the temperature rise due to the combustion of the gas burner. Thereby, even in a low temperature state immediately after the ignition of the gas burner, good combustion is performed without causing lift of the flame.

In this case, for example, in the first control step, the supply amount of the combustion air is controlled to the target amount at least immediately after the ignition of the gas burner, and the fuel gas is supplied at least immediately after the ignition of the gas burner. By controlling the amount to be larger than the target amount by a predetermined amount, the amount of fuel gas is controlled to be relatively large with respect to the amount of combustion air supplied to the gas burner as compared with the normal case. It Then, by gradually changing the supply amount of the fuel gas toward the target amount from this state, the ratio of the supply amounts of the combustion air and the fuel gas is gradually adjusted so as to adapt to the temperature rise due to the combustion of the gas burner. While changing, it is controlled to an appropriate ratio corresponding to the required combustion amount.

Alternatively, in the first control step,
At least immediately after the ignition of the gas burner, the supply amount of the fuel gas is controlled to the target amount, and at least immediately after the ignition of the gas burner, the supply amount of the combustion air is controlled to be smaller than the target amount by a predetermined amount. As a result, the amount of fuel gas is controlled to be relatively large with respect to the amount of combustion air supplied to the gas burner as compared with the normal case. Then, by gradually changing the supply amount of the combustion air from this state toward the target amount, the temperature of the gas burner is increased by the combustion, and the ratio of the supply amounts of the combustion air and the fuel gas is adjusted. It is controlled to an appropriate ratio corresponding to the required combustion amount while gradually changing.

According to the second aspect of the present invention, when a plurality of gas burners are selectively switched to burn,
Immediately after the ignition of the other gas burner that is newly burned by the switching, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is the amount of the fuel gas to the target amount of the combustion air corresponding to the required combustion amount. The supply amounts of the combustion air and the fuel gas are controlled so as to be larger than the ratio of the target amount, and thereafter, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is the fuel gas to the target amount of the combustion air. Since the control is performed to control the supply amounts of the combustion air and the fuel gas so as to gradually match the target amount ratio of
Similar to the first aspect, even in the low temperature state immediately after the ignition of the other gas burner, good combustion is performed without causing a flame lift.

In this case, the switching of the gas burner temporarily supplies the fuel gas to both the gas burner and another gas burner to be newly burned during the combustion of at least one gas burner, and in this state, the fuel gas is burned. Transfer the fire from the gas burner to the other gas burner, ignite and burn the other gas burner, and then supply the fuel gas to the burning gas burner while continuing to supply the fuel gas to the other gas burner. When performed by shutting off, by performing the first control step immediately after the other gas burner is ignited by transferring the fire to the other gas burner,
The ratio of the supply amount of the fuel gas to the supply amount of the combustion air immediately after the ignition of the other gas burner becomes appropriate.

Further, similar to the first aspect, for example, in the first control step, the supply amount of the combustion air is controlled to the target amount at least immediately after the ignition of the gas burner, and at least the gas burner is controlled. When the amount of fuel gas is normal relative to the amount of combustion air supplied to the gas burner by controlling the supply amount of the fuel gas to be larger than the target amount by a predetermined amount immediately after ignition. It is controlled a little more than. Then, by gradually changing the supply amount of the fuel gas toward the target amount from this state, the ratio of the supply amounts of the combustion air and the fuel gas is gradually adjusted so as to adapt to the temperature rise due to the combustion of the gas burner. While changing, it is controlled to an appropriate ratio corresponding to the required combustion amount.

Alternatively, in the first control step,
At least immediately after the ignition of the gas burner, the supply amount of the fuel gas is controlled to the target amount, and at least immediately after the ignition of the gas burner, the supply amount of the combustion air is controlled to be smaller than the target amount by a predetermined amount. As a result, the amount of fuel gas is controlled to be relatively large with respect to the amount of combustion air supplied to the gas burner as compared with the normal case. Then, by gradually changing the supply amount of the combustion air from this state toward the target amount, the temperature of the gas burner is increased by the combustion, and the ratio of the supply amounts of the combustion air and the fuel gas is adjusted. It is controlled to an appropriate ratio corresponding to the required combustion amount while gradually changing.

In the first and second aspects of the present invention, in particular, the gas burner includes a flat first flame hole and second flame holes formed on both sides of the first flame hole. In the first flame hole, a fuel gas leaner than the stoichiometric air-fuel ratio is used to burn the air-fuel mixture, and in the second flame hole, a fuel gas richer than the stoichiometric air-fuel ratio is used to burn the air-fuel mixture mixture. In the case of a so-called low NOx gas burner, as described above, by increasing the supply amount of the fuel gas immediately after the ignition of the gas burner, and then gradually increasing the supply amount appropriately, the first flame of the gas burner is increased. It is possible to effectively suppress the occurrence of lift in the hole.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described with reference to FIGS. 1 is a system configuration diagram of a gas water heater to which the ignition and combustion method of this embodiment is applied, FIG. 2 is a block configuration diagram of a main part of the water heater of FIG. 1, and FIG. 3 is a perspective view of a gas burner of the water heater of FIG. 4 and 5 are diagrams for explaining the operation of the water heater of FIG.

Referring to FIG. 1, the gas water heater of this embodiment comprises a water heater main body 1 and a remote controller 2 connected thereto.

The water heater main body 1 and the heat exchange water passage 3 and gas burners (gas burner group) 4a, 4 having different combustion abilities.
b (for example, 10000 kcal and 20000 kcal), a combustion chamber 5 accommodating these gas burners 4a and 4b, a combustion fan 6 for introducing combustion air into the combustion chamber 5, and a control unit 7
And a gas supply passage 8 for supplying fuel gas to the gas burners 4a, 4b.

The heat exchange channel 3 includes a water supply pipe 9 and a heat exchanger pipe 1.
0, a bypass pipe 11 and a hot water discharge pipe 12.

The water supply pipe 9 is connected on the upstream side to water supply,
The downstream side is connected to the inlet of the electric water flow controller 13. A water filter / drainage plug 14, a water amount sensor 15, and a water supply thermistor 16 are arranged in the water supply pipe 9 from the upstream side. The water amount sensor 15 is an impeller type and sends out a pulse according to the amount of water flowing through the water supply pipe 9. The water supply thermistor 16 is for detecting the water supply temperature.

The heat exchanger tube 10 has its upstream inlet side connected to one outlet side of the electric water amount control device 13, the heat exchanger 17 in the middle thereof is disposed above the gas burners 4a and 4b, and the downstream outlet side thereof is the hot water outlet pipe 12. It is connected to the. The heat exchanger 17 is
Heat the water passing through it. An overheat prevention device 18 is provided on the outer wall, and the can body thermistor 1 is provided on the downstream outlet side.
9 are provided. The can body thermistor 19 is arranged to detect the temperature of water (hot water) passing through the heat exchanger 17.

The bypass pipe 11 has an upstream inlet connected to the other outlet of the electric water flow controller 13, and a downstream end connected to an upstream side of the hot water outlet pipe 12 (downstream end of the heat exchanger pipe 10). The electric water amount control device 13 is controlled by the control unit 7 and reaches the tap water pipe 12 without passing through the water amount passing through the water supply pipe 9 and the heat exchange water amount passing through the heat exchanger pipe 10 and the heat exchanger pipe 10. The ratio with the amount of bypass water flowing through the bypass pipe 11 is controlled.

A freezing prevention heater 20 for preventing freezing and a hot water thermistor 2 for detecting a hot water temperature are provided in the hot water discharge pipe 12.
1. Overpressure safety valve and drain plug 22, Hot water tap 2 for tapping hot water
3 is arranged from the upstream side to the downstream side. The hot water tap 23 is a faucet (not shown) arranged in a kitchen or a bathroom.
It is a faucet that adjusts the amount of hot water discharged from.

The gas supply passage 8 includes a main gas pipe 26 having a source solenoid valve 24 and a governor proportional solenoid valve 25 arranged from the upstream side,
It is configured by auxiliary gas pipes 27a and 27b that are branched from the downstream end of the main gas pipe 26 and introduced into the combustion chamber 5. The governor proportional solenoid valve 25 is energized and controlled by the control unit 7, and continuously changes the flow rate of the fuel gas flowing through the main gas pipe 26 according to the energization amount.

An auxiliary gas pipe 27 branched from the main gas pipe 26
a and 27b respectively supply the fuel gas to the gas burners 4a and 4b, respectively.
Capacity switching solenoid valves 28a and 28b are provided at locations where 27b is branched from the main gas pipe 26, respectively. The capacity switching solenoid valves 28a and 28b are gas burners 4a and 4b.
When burning, the gas burners 4a, 4 for supplying fuel gas to either or both of them for combustion.
It is for switching b, and is opened and closed under the control of the control unit 7. That is, when burning only the gas burner 4a or 4b, the capacity switching solenoid valve 28a
Alternatively, when only 28b is opened and both of the gas burners 4a and 4b are combusted, the capacity switching solenoid valves 28a and 28b
Both b are opened. As a result, the combustion ability can be switched between three stages depending on whether the gas burners 4a or 4b are burned or both are burned.

The portions of the sub gas pipes 27a and 27b introduced into the combustion chamber 5 are further branched into a pair of branch pipes 29 and 30, respectively, as shown in FIG. A plurality of nozzles 31 and 32 for supplying fuel gas to the gas burners 4a and 4b are respectively arranged in rows in the branch pipes 29 and 30 of the sub gas pipes 27a and 27b.

Now, referring to FIG. 3, each gas burner 4
a and 4b are disclosed in, for example, Japanese Patent Application No. 3-26350
A plurality of low NOx gas burners 33 (hereinafter referred to as unit gas burners 33) proposed in No. 5 are arranged in parallel in the combustion chamber 5. In this case, the number (for example, 11) of the unit gas burners 33 that configure the gas burner 4a is greater than the number (for example, 6) of the unit gas burners 33 that configure the gas burner 4b, so that the combustion capability of the gas burner 4a is increased. It is considered to be larger than the burning capacity of.

The configuration of the unit gas burner 33 is as follows.
Since detailed description is given in No. 263505, detailed description thereof will be omitted here, but the outline of the configuration is as follows.

That is, the unit gas burner 33 has a flat first flame hole 34 and a pair of second flame holes 35, 35 provided on both sides of the first flame hole 34. Further, in the unit gas burner 33, a pair of second flame holes is provided independently of a first suction hole 36 communicating with the first flame hole 34 and a passage 37 communicating from the first suction hole 36 to the first flame hole 34. A second suction hole 38 that communicates with both 35 and 35 is provided, and the first suction hole 36 and the second suction hole 38 are provided in each gas burner 4.
nozzles 31 and 3 of the branch pipes 29 and 30 corresponding to a and 4b
2 are facing each other. Also, the unit gas burner 33
A plate-shaped damper 39 is arranged between the first suction hole 36 and the second suction hole 38 of the first suction hole 36 and the second suction hole 38, and the nozzles 31 and 32 opposed to the first suction hole 36 and the second suction hole 38. And the second suction hole 38 and the nozzle 32 are respectively formed with throttle holes 40 and 41.

In each of the gas burners 4a and 4b constituted by the unit gas burner 33, when the fuel gas is supplied to the branch pipes 29 and 30 of the corresponding sub gas pipes 27a and 27b, the nozzle 31 of the branch pipe 29 is supplied. Fuel gas is injected into the first suction hole 36 of the unit gas burner 33 from the damper 39 through the throttle hole 40 of the damper 39, and at the same time, the fuel gas is supplied to the combustion chamber 5 in the process of being supplied to the first suction hole 36. The primary air for combustion supplied by the combustion fan 6 mixes with the fuel gas, and the mixture is supplied from the first suction hole 36 to the first flame hole 34 and burned in the first flame hole 34.
In parallel with this, the fuel gas is injected from the nozzle 32 of the branch pipe 30 into the second suction hole 38 of the unit gas burner 33 through the throttle hole 41 of the damper 39, and at the same time, the fuel gas is injected into the combustion chamber 5 at the same time. The primary air for combustion supplied by the combustion fan 6 mixes with the fuel gas, and the mixture is supplied from the second suction hole 38 to the second flame holes 35, 35 and burns in the second flame holes 35, 35. To be done. In this case, by appropriately setting the sizes of the nozzles 31 and 32 and the diameters of the throttle holes 40 and 41, the air-fuel mixture to be burned in the first flame holes 34 has a fuel gas higher than the theoretical air-fuel ratio. The air-fuel mixture that is made lean (air-rich air-fuel mixture) and burned in the second flame holes 35, 35 has a fuel gas richer than the stoichiometric air-fuel ratio (gas-rich air-fuel mixture). Low N
Ox conversion is planned. In FIG. 1, 42 is an ignition electrode, 43 is an igniter, 44 is a frame rod for detecting combustion flame, 45 is a temperature fuse for preventing overheating, and 46 is a low temperature detection switch for operating the antifreezing heater 20. Is. In addition, an exhaust duct 48 that collects the combustion exhaust gas 47 and discharges the combustion exhaust gas 47 to the outside is extended in the upper portion of the combustion chamber 5. Further, the remote controller 2 is provided with a temperature setting switch 49, an operation switch 50, a display (not shown), and the like. The frame rod 44 is a gas burner 4a, 4
The combustion flame can be detected even when only the gas burner 4a or only the gas burner 4b is ignited.

Next, referring to FIG. 2, the control unit 7 has a microcomputer (not shown), and its main functional configuration is the required combustion amount calculation section 5
1, a fan control unit 52, a proportional valve control unit 53, a capacity switching valve control unit 54, and an original solenoid valve control unit 55.

The required combustion amount calculation unit 51 sets the set temperature set by the temperature setting switch 49 of the remote controller 2 based on the supplied water temperature, the amount of water detected by the water supply thermistor 16, the water amount sensor 15, and the hot water discharge thermistor 21. The required combustion amount of the gas burners 4a and 4b that matches the hot water temperature is calculated using a predetermined arithmetic expression or the like.

The fan control unit 52 basically supplies a target amount of combustion air corresponding to the required combustion amount obtained by the required combustion amount calculation unit 51 to the gas burners 4a, 4a in the combustion chamber 5.
The target rotation speed of the combustion fan 6 is set so that the combustion fan 6 is supplied to the combustion fan 6, and the rotation speed of the combustion fan 6 detected by the rotation speed sensor 56 provided in the combustion fan 6 matches the target rotation speed. The rotation speed of 6 is feedback-controlled.

The proportional valve control unit 53 basically supplies an amount of fuel gas corresponding to the amount of combustion air supplied to the combustion chamber 5 at the rotation speed of the combustion fan 6 detected by the rotation speed sensor 56. The target energization amount of the governor proportional solenoid valve 25 is set according to the rotation speed of the combustion fan 6 detected by the rotation speed sensor 56 so as to be supplied to the gas burners 4a and 4b. By supplying electricity, the supply amount of fuel gas is controlled. This control is a so-called fan preceding control. In this case, the rotation speed of the combustion fan 6 is controlled to the target rotation speed corresponding to the required combustion amount by the fan control unit 52, so that the supply amount of the fuel gas is controlled by the control of the governor proportional solenoid valve 25 as described above. The target amount is indirectly controlled to correspond to the required combustion amount. The proportional valve control unit 53 uses the governor proportional solenoid valve 25 as described later.
Control.

The capacity switching valve control unit 54 controls the opening / closing of the capacity switching electromagnetic valves 28a and 28b according to the required combustion amount calculated by the required combustion amount calculation unit 51. That is, in a predetermined range in which the required combustion amount is relatively small, only the capacity switching electromagnetic valve 28b on the gas burner 4b side (hereinafter referred to as the small burner 4b) having a small combustion capacity is opened and the small burner 4b is opened.
In the predetermined range of the required combustion amount larger than that, the capacity switching solenoid valve 28a on the side of the gas burner 4a (hereinafter referred to as the large burner 4a) having a large combustion capacity is opened to burn the large burner 4a. For further required combustion amount, both capacity switching solenoid valves 28a, 28b are opened to burn both burners 4a, 4b.
The opening / closing control of the capacity switching solenoid valves 28a and 28b is performed.

The original solenoid valve control unit 55 includes a gas burner 4a,
When starting and stopping the combustion of 4b, the original solenoid valve 24
Open / close control.

Next, the operation of the water heater of this embodiment will be described.

When the water flow through the heat exchange channel 3 is started while the operation switch 50 of the remote controller 2 is turned on, it is detected by the control unit 7 via the water amount sensor 15.

At this time, the control unit 7 causes the fan controller 52 to rotate the combustion fan 4 at a predetermined number of revolutions to pre-purge the inside of the combustion chamber 5, and then performs an ignition process as follows.

That is, the control unit 7 causes the fan controller 52 to rotate the combustion fan 6 at a predetermined rotation speed so as to supply the combustion chamber 5 with a proper predetermined amount of combustion air for ignition. In parallel with this, the control unit 7 causes the source solenoid valve control unit 55 to open the source solenoid valve 24, and the capability switching valve control unit 54 causes the capability switching solenoid valves 28a and 28b to, for example, Burner 4b
The side capacity switching solenoid valve 28b is opened.
The supply of fuel gas to the small burner 4b is started. further,
At this time, the control unit 7 causes the proportional valve control unit 53 to apply the predetermined energization amount to the governor proportional solenoid valve 25 so that an appropriate predetermined amount of fuel gas for ignition is supplied to the small burner 4b. Energize. In this state, the ignition electrode 42 is spark-discharged to ignite the small burner 4b.

Then, after confirming the ignition of the small burner 4b via the frame rod 44, the control unit 7 causes the fan control unit 52 to determine the required combustion amount calculated by the required combustion amount calculation unit 51. The rotation speed of the combustion fan 6 is feedback-controlled so that the combustion fan 6 is rotated at the target rotation speed set corresponding to the required combustion amount.
As a result, the target amount of combustion air corresponding to the required combustion amount is supplied to the small burner 4b in the combustion chamber 5.

On the other hand, the proportional valve control section 53 of the control unit 7
Immediately after the small burner 4b is ignited, as shown in FIG. 4, with a predetermined energization amount (for example, 10 mA) larger than the target energization amount corresponding to the rotation speed of the combustion fan 6 controlled as described above, The governor proportional solenoid valve 25 is energized.

Thus, the target amount of combustion air corresponding to the required combustion amount is supplied from the combustion fan 6 to the small burner 4b in the combustion chamber 5 immediately after ignition, while the combustion gas is used for combustion. A slightly larger amount of fuel gas than the target amount of fuel gas corresponding to the supply amount of air is supplied. In other words, rather than the ratio of the target amount of fuel gas to the target amount of combustion air corresponding to the required combustion amount (this ratio is set so as to obtain optimum combustion during continuous combustion) Combustion air and fuel gas are supplied to the small burner 4b in the combustion chamber 5 at a slightly large rate.

Next, the control unit 7 continuously controls the rotation speed of the combustion fan 6 to the target rotation speed corresponding to the required combustion amount by the fan control unit 52, and the proportional valve control unit 53.
As a result, the increase in the energization amount to the governor proportional solenoid valve 25 with respect to the target energization amount (10 mA immediately after ignition) is gradually decreased as shown in FIG. 4 to finally match the target energization amount. As a result, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air supplied to the small burner 4b in the combustion chamber 5 is the target amount of the fuel gas to the target amount of the combustion air corresponding to the required combustion amount. It gradually changes toward a ratio (hereinafter referred to as a target ratio), and is finally controlled to the target ratio. In this case, in the present embodiment, immediately after the small burner 4b is ignited, the fuel gas is increased for a predetermined time (for example, 2 minutes, the time indicated by the reference symbol “T” in FIG. 4) from the state where the fuel gas is increased beyond the target amount. The amount of increase in the supply amount of the fuel gas is gradually reduced so that the supply amount of is equal to the target amount.

As described above, by controlling the ratio of the supply amount of the fuel gas to the supply amount of the combustion air at the early stage of combustion due to the ignition of the small burner 4b, the temperature of the small burner 4b immediately after the ignition is low, After a large amount of fuel gas is supplied to the small burner 4b with respect to the supply amount of combustion air,
The small burner 4b gradually changes so as to match the target amount, so that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is a ratio according to the temperature state of the small burner 4b.
Therefore, the small burner 4b satisfactorily burns without causing lift of combustion flame or the like. In particular, the small burner 4b in the present embodiment burns a mixture of lean fuel gas and combustion air in the first flame holes 34 of the unit gas burner 33, so lift occurs in a low temperature immediately after ignition. Although it is easy, a large amount of fuel gas is added to the small burner 4b as described above.
By supplying to, the combustion is excellent without causing lift.

When the supply amounts of both the combustion air and the fuel gas are finally controlled to the target amounts corresponding to the required combustion amount, the temperature of the small burner 4b has risen sufficiently. The burner 4b burns well with the required amount of combustion while exhibiting the original low NOx property.

In the above description, the case of igniting the small burner 4b has been described, but the same applies to the case of igniting the large burner 4a.

Next, in the water heater of the present embodiment, combustion is performed in accordance with the required combustion amount obtained by the required combustion amount calculation section 51 of the control unit 7 during the combustion of the large burner 4a or the small burner 4b. The changeover of the pressurizing burners 4a and 4b is performed as follows.

That is, for example, during the combustion of the small burner 4b, the required combustion amount calculation unit 51 calculates a required combustion amount that exceeds the required combustion amount within a predetermined range corresponding to the combustion capacity of the small burner 4b. If required,
The control unit 7 causes the capacity switching valve control unit 54 to open the capacity switching electromagnetic valve 28a on the large burner 4a side while keeping the capacity switching electromagnetic valve 28b on the small burner 4b side open. At the same time, as shown in FIG. 5, the proportional valve control unit 53 increases the energization current to the governor proportional solenoid valve 25 by a predetermined amount (for example, 30 mA) with respect to the current energization current, and temporarily holds that state for a predetermined time. Hold (for example, 0.6 seconds). As a result, the fuel gas is temporarily supplied to both the burners 4a and 4b, and the small burner 4b during burning to the large burner 4 is burning.
The flame is transferred to a, and the large burner 4a is ignited and burned.

When the predetermined time has elapsed, the control unit 7 closes the capacity switching electromagnetic valve 28b on the small burner 4b side to cut off the supply of the fuel gas to the small burner 4b, thereby turning off the small burner 4b. extinguish a fire.

At this time, the rotation speed of the combustion fan 6 is controlled by the fan control unit 52 to a target rotation speed corresponding to the required combustion amount, and the energization amount to the governor proportional solenoid valve 25 is equal to or above the predetermined time. Immediately after that, as in the case of the ignition described above, as shown in FIG. 5, the proportional valve control unit 53 controls the energization amount larger by a predetermined amount (10 mA) than the target energization amount corresponding to the rotation speed of the combustion fan 6. It After that, just as in the case of the above-described ignition, the amount of increase in the energization amount to the governor proportional solenoid valve 25 with respect to the target energization amount is gradually reduced, and after the predetermined time T shown in FIG. Controlled by quantity. The target energization amount of the governor proportional solenoid valve 25 in this case is the target energization amount determined for the large burner 4a.

As a result, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air supplied to the large burner 4a in the combustion chamber 5 is the same as in the case of the ignition described above.
Immediately after the ignition of a, the target ratio is set to be slightly larger than the target ratio, then gradually changed, and finally controlled to the target ratio.

By performing such control, when the combustion is switched from the small burner 4b to the large burner 4a as described above, the large burner 4a can be satisfactorily enlarged in a low temperature state without causing lift. Burner 4a is burned,
The low NOx property of the large burner 4a is secured.

Such control is similarly performed when the required combustion amount is reduced during the combustion of the large burner 4a and the combustion is switched to the small burner 4b. As described above, in the water heater of the present embodiment, when the burner 4b is ignited or when the combustion of both burners 4a, 4b is switched,
By controlling the supply amount of the fuel gas to the burner 4a or 4b to be burned to a larger amount with respect to the target amount and gradually controlling it to match the target amount, good combustion can be achieved without causing lift of the flame. It can be carried out.

In the embodiment described above, when the burner 4a or 4b is ignited and burned, the amount of combustion air supplied by the combustion fan 6 is controlled to a target amount, and the governor proportional solenoid valve 25 is energized. I tried to control the amount of fuel gas supplied by the control a little more than the target amount, but on the contrary,
Immediately after the burner 4a or 4b is ignited, the supply amount of the fuel gas is controlled to the target amount, and immediately after the ignition, the supply amount of the combustion air by the combustion fan 6 is controlled to be smaller than the target amount. The air supply amount may be gradually increased to the target amount.

Further, although the present embodiment has been described by taking the water heater as an example, it goes without saying that the present invention can be applied to other gas combustion equipment such as a gas fan heater.

Further, in the present embodiment, the low NOx gas burner 33 is shown as the gas burner, but a gas burner which burns at a stoichiometric air-fuel ratio may be used.

Although the fan-leading type is shown in this embodiment, the present invention is not limited to the fan-leading type.

[0067]

As is apparent from the above description, according to the present invention, immediately after the ignition of the gas burner, the ratio of the fuel gas supply amount to the combustion air supply amount corresponds to the required combustion amount. The target amount of the fuel gas is controlled to be larger than the target amount of the fuel gas, and the supply amount of the combustion gas is controlled so that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is thereafter adjusted. By controlling the supply amounts of the combustion air and the fuel gas so that the ratio of the target amount of the fuel gas to the target amount of is gradually controlled, during the ignition of the gas burner or during the combustion of a certain gas burner. When switching to another gas burner according to the required amount of combustion and burning it, it is possible to prevent the occurrence of lift of the flame, which allows the gas burner to be continuously burned immediately after ignition. It is possible to perform good combustion.

Therefore, in particular, when the present invention is applied to a gas burner designed to reduce NOx, its low NOx property can be sufficiently secured immediately after ignition, and it is effective in performing clean combustion. is there.

Further, immediately after the ignition of the gas burner, the supply amount of combustion air is controlled to the target amount, and immediately after the ignition of the gas burner, the supply amount of the fuel gas is controlled to be larger than the target amount by a predetermined amount. , Then, by gradually changing the fuel gas supply amount toward the target amount while controlling the combustion air supply amount to the target amount, or by setting the fuel gas supply amount to the target amount immediately after ignition of the gas burner. The amount of combustion air is controlled to be smaller than the target amount by a predetermined amount immediately after the gas burner is ignited, and then the amount of fuel gas is controlled to the target amount while the combustion air is controlled. It is possible to easily control the supply amounts of the combustion air and the fuel gas, which have the above-mentioned effects, by gradually changing the supply amount of the fuel gas toward the target amount.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a gas water heater to which an example of the present invention is applied.

FIG. 2 is a block configuration diagram of a main part of the water heater of FIG.

3 is a perspective view of a gas burner used in the water heater of FIG.

FIG. 4 is a diagram for explaining an operation at the time of ignition of the gas burner of the water heater of FIG.

5 is a diagram for explaining the operation of the gas burner of the water heater of FIG. 1 when switching combustion.

[Explanation of symbols]

 4a, 4b ... Gas burner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Kitagawa 2-26 Fukuzumicho, Nakagawa-ku, Nagoya, Aichi Prefecture

Claims (8)

[Claims] Claim: What is claimed is: 1. A gas burner housed in a combustion chamber is controlled by controlling the supply amounts of the combustion air and the fuel gas so as to supply a target amount of the combustion air and the fuel gas corresponding to the required combustion amount. In the ignition combustion method of a gas burner for performing combustion, at least immediately after ignition of the gas burner, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is relative to the target amount of combustion air corresponding to the required combustion amount. A first control for controlling the supply amounts of the combustion air and the fuel gas so as to be larger than the ratio of the target amount of the fuel gas
A control step, and thereafter, the combustion air and the fuel gas so that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air gradually matches the ratio of the target amount of the fuel gas to the target amount of the combustion air. And a second control step of controlling the supply amount of the gas burner. 2. The first control step controls the supply amount of the combustion air to a target amount at least immediately after ignition of the gas burner, and controls the supply amount of the fuel gas at least immediately after ignition of the gas burner. The second control step controls the supply amount of the combustion air to the target amount while gradually changing the supply amount of the fuel gas toward the target amount by controlling the supply amount of the combustion air to be larger than the target amount by a predetermined amount. The method for igniting and burning a gas burner according to claim 1, wherein the method is ignition. 3. The first control step controls the supply amount of the fuel gas to a target amount thereof at least immediately after ignition of the gas burner, and controls the supply amount of the combustion air at least immediately after ignition of the gas burner. The second control step controls the supply amount of the fuel gas to the target amount while gradually changing the supply amount of the combustion air toward the target amount by controlling the supply amount of the fuel gas to be smaller than the target amount by a predetermined amount. The method for igniting and burning a gas burner according to claim 1, wherein the method is ignition. 4. At least one gas burner selected from a plurality of gas burners arranged in parallel in a combustion chamber and having different combustion capacities is selected, and a target amount of combustion air and fuel gas corresponding to a required combustion amount is selected for the gas burner. The step of controlling the supply amounts of the combustion air and the fuel gas so that the gas burner is burned, and another gas burner for switching the gas burner to be burned according to the required combustion amount during the combustion of the gas burner. To newly ignite the other gas burner and supply the combustion air and the fuel gas to the other gas burner so as to supply the target amount of the combustion air and the fuel gas corresponding to the required combustion amount. Controlling the combustion of the other gas burner to perform combustion of the other gas burner, at least the other gas bar. Immediately after ignition, the combustion gas is supplied such that the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is larger than the ratio of the target amount of the fuel gas to the target amount of the combustion air corresponding to the required combustion amount. A first control step of controlling the supply amounts of the working air and the fuel gas, and thereafter, the ratio of the supply amount of the fuel gas to the supply amount of the combustion air is the ratio of the target amount of the fuel gas to the target amount of the combustion air. And a second control step of controlling the supply amounts of the combustion air and the fuel gas so as to gradually coincide with the above. 5. The gas burner is switched by temporarily supplying fuel gas to both the gas burner and another gas burner to be newly burned during combustion of at least one gas burner, and in this state, the burning gas burner. To the other gas burner, ignite and burn the other gas burner, and then interrupt the supply of fuel gas to the burning gas burner while continuing to supply fuel gas to the other gas burner. The ignition combustion method for a gas burner according to claim 3, wherein the first control step is performed immediately after the other gas burner is ignited by the transfer of the fire to the other gas burner. 6. The first control step controls the supply amount of the combustion air to a target amount at least immediately after the ignition of the other gas burner, and at least immediately after the ignition of the gas burner, the supply amount of the fuel gas. Is controlled to be larger than the target amount by a predetermined amount, and the second control step controls the supply amount of the combustion air toward the target amount while controlling the supply amount of the combustion air to the target amount. The ignition burning method for a gas burner according to claim 4 or 5, wherein the method is gradually changed. 7. The first control step controls the supply amount of the fuel gas to a target amount at least immediately after ignition of the other gas burner, and supplies the combustion air at least immediately after ignition of the gas burner. Is controlled to be smaller than the target amount by a predetermined amount, and the second control step controls the supply amount of the combustion gas toward the target amount while controlling the supply amount of the fuel gas to the target amount. The ignition burning method for a gas burner according to claim 4 or 5, wherein the method is gradually changed. 8. The gas burner comprises a first flame hole and second flame holes formed on both sides of the first flame hole, and burns with a fuel gas leaner than the stoichiometric air-fuel ratio in the first flame hole. 8. A gas burner for burning an air-fuel mixture with combustion air, and for combusting the air-fuel mixture with combustion air at a second flame hole with a fuel gas richer than the stoichiometric air-fuel ratio.
5. A method for igniting and burning a gas burner according to claim 1.