JP3460890B2 - Combustion equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device such as a water heater.

[0002]

2. Description of the Related Art Conventionally, in this type of combustion apparatus, in order to supply an appropriate amount of combustion air to a burner housed in a combustion chamber by means of a combustion fan, a required amount of combustion of the burner is followed by a predetermined table or the like. It is generally known that a reference rotation speed of a combustion fan is set, and the rotation speed of the combustion fan is controlled using the reference rotation speed as a target rotation speed. In this case, the reference rotation speed is a combustion fan capable of supplying the burner with an appropriate amount of combustion air corresponding to the required combustion amount when the air passage for supplying and exhausting the burner is normal. Is predetermined as the number of revolutions of.

On the other hand, in the combustion apparatus of this type, when the ventilation passage is closed, the amount of combustion air supplied to the burner can be increased only by controlling the rotation speed of the combustion fan to the reference rotation speed. Therefore, the rotation speed of the combustion fan is corrected according to the degree of blockage of the ventilation passage (the higher the degree of blockage,
It is preferable to supply the burner with an appropriate amount of combustion air corresponding to the required combustion amount of the burner even if the ventilation passage is somewhat blocked, by increasing the rotation speed of the combustion fan.

Therefore, the inventor of the present application has found that the higher the degree of blockage of the ventilation passage, the higher the rotation speed of the combustion fan is.
Focusing on the fact that the amount of electricity supplied to the combustion fan (the amount of electricity supplied to the fan motor) decreases accordingly, the amount of electricity supplied to the combustion fan is detected during burner combustion, and the ventilation passage is blocked based on the detected amount of electricity supplied. We are trying to grasp the degree. Then, the target rotation speed of the combustion fan is obtained while correcting the reference rotation speed of the combustion fan corresponding to the required combustion amount according to the grasped degree of blockage, and an attempt is made to control the combustion fan according to the target rotation speed. . By correcting the rotation speed of the combustion fan in this way, an appropriate amount of combustion air corresponding to the required combustion amount of the burner can be supplied to the burner even if the ventilation passage is slightly blocked.

According to a further study by the inventor of the present application, the sliding resistance during rotation of the combustion fan is relatively high in the initial combustion state of the burner where the ambient temperature of the combustion fan is relatively low. Therefore, when the number of rotations of the combustion fan is constant, the initial state of combustion of the burner (for example, 40 ° C)
Then, compared to a state in which the ambient temperature of the combustion fan has become sufficiently high due to the continuous combustion of the burner, the amount of electricity supplied to the combustion fan tends to increase.

Therefore, when the degree of obstruction of the air passage is grasped based on the detected energization amount to the combustion fan as described above, the degree of obstruction of the air passage is such that the combustion of the burner continuously progresses to some extent in the early stage of combustion of the burner. Compared to the stage you did, you will be grasped smaller. Therefore, if the number of revolutions of the combustion fan is corrected in accordance with the degree of blockage of the ventilation passage that is grasped by the detected energization amount to the combustion fan immediately after the combustion of the burner is started, the burner by the combustion fan is used at the initial stage of combustion of the burner. There is a risk that the combustion air may be insufficient due to a short supply of combustion air.

[0007]

In view of such a background, the present invention grasps the degree of blockage of the ventilation passage based on the amount of electricity supplied to the combustion fan, and the combustion fan corresponding to the required combustion amount of the burner according to the degree of blockage. It is an object of the present invention to provide a combustion device that corrects the number of rotations of the burner and can appropriately perform combustion of the burner by appropriately supplying combustion air to the burner by a combustion fan immediately after the start of combustion of the burner. And

[0008]

In order to achieve the above object, the present invention provides a burner housed in a combustion chamber, a combustion fan for supplying combustion air to the burner, and a required combustion amount of the burner. Reference speed setting means for setting a reference speed of the combustion fan for supplying a corresponding amount of combustion air to the burner, and energization amount detection for detecting an energization amount of the combustion fan during combustion of the burner. Means, and the degree of blockage of the ventilation passage for performing air supply / exhaust of the burner based on the detected amount of power of the combustion fan obtained by the amount of current detection means, and the reference rotation according to the degree of blockage. Target rotation speed calculating means for correcting the number of rotations to obtain the target rotation speed of the combustion fan, and a fan control for controlling the rotation speed of the combustion fan so as to comply with the target rotation speed calculated by the target rotation speed calculating means. In the combustion and means,
The target rotation speed calculation means sets a target rotation speed that is larger than a target rotation speed that is obtained by correcting the reference rotation speed according to the degree of blockage of the ventilation passage during the initial combustion after the burner starts combustion. Characterized by seeking.

Then, the target rotation speed calculation means calculates a correction value for obtaining a correction value for correcting the reference rotation speed in accordance with the degree of blockage of the air passage which is grasped based on the detected energization amount of the combustion fan. And a correction unit that corrects the reference rotation speed according to the correction value obtained by the correction value calculation unit to obtain the target rotation speed, and the correction unit is provided during the initial combustion after the start of combustion of the burner. The initial rotation speed is obtained by correcting the reference rotation speed with a correction value larger than the correction value of the reference rotation speed according to the degree of blockage of the air passage.

Further, there is provided storage means for storing and holding the correction value calculated by the correction value calculation means during the previous combustion of the burner, and the correction means has the correction value calculation means during the combustion of the burner. When the reference rotation speed is corrected by the correction value obtained by, the reference rotation speed is gradually corrected from the state before correction so as to gradually reach the correction amount of the reference rotation speed corresponding to the correction value. In addition to obtaining the target rotation speed, at the start of the current combustion of the burner, an initial rotation speed obtained by correcting the reference rotation speed with a correction value larger than the correction value stored and held in the storage means is obtained as the target rotation speed. It is characterized by

[0011]

According to the present invention, in the initial combustion state after the combustion of the burner is started, when the ambient temperature of the combustion fan is relatively low, the fan control means drives the combustion fan at the target rotation speed. The amount of electricity supplied to the burner is greater than that at the stage where combustion of the burner progressed to some extent. Therefore, the degree of blockage of the ventilation passage, which is grasped based on the detected amount of electricity supplied to the combustion fan obtained by the amount of electricity detecting means, is smaller than the actual degree of blockage. Therefore, the target rotation speed calculation means, in the initial combustion state of the burner, obtains a larger initial rotation speed than the target rotation speed obtained by correcting the reference rotation speed according to the degree of blockage of the ventilation passage, Instruct the fan control means. At this time, the rotation speed of the combustion fan controlled by the fan control means to the initial rotation speed is a sufficient amount for burning the burner at the required combustion amount depending on the current actual degree of blockage of the ventilation passage. The fuel air can be supplied. It should be noted that the initial rotation speed that is determined to be larger than the target rotation speed that is obtained by correcting the reference rotation speed according to the degree of blockage of the ventilation passage that is grasped based on the detected energization amount of the combustion fan is the actual rotation speed of the ventilation passage. It is preferable that the reference rotation speed is corrected according to the degree of blockage so that the reference rotation speed is substantially equal to the target rotation speed.

In the present invention, when the correction value of the reference rotation speed is obtained by the correction value calculation means and the reference rotation speed is corrected by the correction means according to the correction value to obtain the target rotation speed, In the initial combustion state, the reference rotation speed is corrected by a correction value larger than the correction value of the reference rotation speed according to the degree of blockage of the ventilation passage, which is grasped based on the detected energization amount of the combustion fan, and the initial rotation speed is adjusted. By determining, the determined initial rotation speed becomes a target rotation speed that is larger than the target rotation speed according to the degree of blockage of the ventilation passage that is grasped based on the detected energization amount of the combustion fan as described above. .

Further, when the correction means corrects the reference rotation speed by the correction value obtained by the correction value calculation means during combustion of the burner, the correction amount of the reference rotation speed corresponding to the correction value. In order to gradually obtain the target rotation speed while gradually correcting the reference rotation speed from the state before correction so that the correction value calculated by the correction value calculation means during the previous combustion of the burner is When stored in the storage means, the correction means corrects the reference rotational speed by a correction value larger than the correction value stored and stored in the storage means at the start of combustion of the burner at the time of combustion operation of the burner this time. Then, the initial rotation speed of the combustion fan is obtained. At this time, in the initial combustion state of the burner this time, for example, if the degree of blockage of the ventilation passage is the same as the degree of blockage during combustion of the previous burner, the correction value calculating means in the initial combustion state of the burner this time The obtained correction value (correction value for obtaining the target rotation speed after the initial rotation speed) is higher than the actual closure degree as described above when the degree of blockage of the ventilation passage grasped from the detected energization amount of the combustion fan is as described above. Due to the small size, it becomes smaller than the correction value (which is equal to the correction value stored and stored in the storage means) corresponding to the actual degree of blockage of the air passage. Then, the correction value obtained by the correction value calculation means gradually reaches the correction value corresponding to the actual degree of blockage of the ventilation path as the combustion of the burner progresses and the ambient temperature of the combustion fan increases. . On the other hand, the correction means sets the reference rotational speed by a correction value larger than a correction value (correction value corresponding to the actual degree of blockage of the ventilation passage) stored and held in the storage means at the start of combustion of the burner this time. After the correction is made to obtain the initial rotation speed of the combustion fan, the reference rotation speed is gradually increased from the state before correction so that the correction amount of the reference rotation speed corresponding to the correction value obtained by the correction value calculation means is gradually reached. Since the target rotational speed is calculated while correcting the target rotational speed, the initial rotational speed larger than the target rotational speed corresponding to the correction value obtained by the correction value calculation means is obtained, and the target rotational speed is the initial rotational speed. Considering the gradual decrease from the number, the overall value is substantially the same as the target rotational speed obtained by correcting the reference rotational speed by the correction value corresponding to the actual degree of blockage of the air passage. Therefore, it is possible to supply sufficient combustion air to the burner by controlling the combustion fan by the fan control means according to the target rotation speed thus obtained.

Further, by gradually performing the correction by the correction means as described above, the correction value calculated by the correction value calculation means when the ventilation passage is temporarily closed due to, for example, a temporary gust of wind. Does not change suddenly, the target speed obtained by the correction means does not change,
The rotation speed of the combustion fan is stable, and a situation in which a large excess or deficiency of the supply amount of combustion air to the burner immediately after the stop of a gust or the like occurs is avoided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the first aspect of the present invention will be described with reference to FIGS. FIG. 1 is a system configuration diagram of a water heater equipped with the combustion apparatus of the present embodiment, FIG. 2 is a block configuration diagram of a main part of the water heater of FIG. 1, and FIGS. 3 to 7 explain the operation of the water heater of FIG. It is a diagram for doing.

Referring to FIG. 1, the 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 includes a water supply passage 3, a gas burner 4, a combustion chamber 5 accommodating the gas burner 4, a combustion fan 6 for supplying combustion air into the combustion chamber 5, a control unit 7, A fuel supply passage 8 for supplying fuel gas to the gas burner 4 is provided.

The water supply passage 3 has a main water supply pipe 9, a heat exchanger pipe 10 and a hot water discharge pipe 11 which are sequentially connected in series from the upstream side to the downstream side thereof, and a bypass connected in parallel to the heat exchanger pipe 10. And the tube 12. At the branch point from the main water supply pipe 9 to the heat exchanger pipe 10 and the bypass pipe 12, the electric water control valve 1 for adjusting the ratio of the amount of water flowing to the heat exchanger pipe 10 and the bypass pipe 12 according to the instruction of the control unit 7.
3 is provided.

The upstream side of the main water supply pipe 9 is connected to the water supply, and 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 on the main 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 8. The water supply thermistor 16 detects the water supply temperature.

The heat exchanger tube 10 has an upstream inlet side connected to one outlet side of the electric water amount control device 13, and an intermediate portion thereof passes through a heat exchanger 17 provided above the gas burner 4,
The downstream outlet side is connected to the hot water outlet pipe 11. Heat exchanger 1
7 is heated by the combustion of the gas burner 4, so that the water flowing inside the heat exchanger tube 10 is heated in the process of passing through the heat exchanger 17. An overheat prevention device 18 is arranged on the outer wall, and a can body thermistor 19 is arranged on the downstream outlet side. The can thermistor 19 detects the hot water temperature of the water that has passed through the heat exchanger 17.

The bypass pipe 12 is connected at the upstream inlet side to the other outlet side of the electric water amount control device 13 to be branched from the original water supply pipe 9, and at the downstream end thereof upstream of the hot water discharge pipe 11 (heat exchanger pipe 1
0 downstream end side).

A freezing prevention heater 20 for preventing freezing and a hot water thermistor 2 for detecting the hot water temperature are provided in the hot water discharge pipe 11.
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 outlet temperature thermistor 21 detects the hot water outlet temperature of the hot water flowing through the hot water outlet pipe 11 of the water supply passage 3 at the downstream side of the confluence of the heat exchanger pipe 10 and the bypass pipe 12. The hot water tap 23 is a hot water tap that adjusts the amount of hot water discharged from a faucet (not shown) arranged in a kitchen or a bathroom.

A main solenoid valve 24 and a governor proportional solenoid valve 25 are arranged in this order from the upstream side of the fuel supply passage 8, and the downstream end thereof is introduced into the combustion chamber 5 to supply the fuel gas to the gas burner 4. ing. The governor proportional solenoid valve 25 is energized and controlled by the control unit 7, and continuously changes the fuel gas supply amount according to the energization amount. The original solenoid valve 24 is opened and closed under the control of the control unit 7, thereby performing fuel supply to the gas burner 4 and interruption of the fuel supply.

In FIG. 1, 26 is an ignition electrode, and 27 is an ignition electrode.
Is an igniter, 28 is a frame rod for detecting a combustion flame, 29 is a temperature fuse for preventing overheating, and 30 is a low temperature detection switch for operating the antifreezing heater 20. Further, in the combustion chamber 5, an exhaust passage 32 (ventilation passage) for collecting the combustion exhaust gas 31 and discharging it to the outside is extended at the upper part, and an air supply passage 33 (ventilation passage) provided with the combustion fan 6 is provided. Are in communication. If necessary, an extension duct (not shown) is connected to the exhaust passage 32.

Further, the remote controller 2 is provided with a temperature setting switch 34, an operation switch 35, a display (not shown) and the like.

Next, referring to FIG. 2, the control unit 7 has a microcomputer (not shown), and its main functional configuration is to calculate the required combustion amount of the gas burner 4 by the required combustion. An amount calculation unit 36, a fan control unit 37 (fan control means) for controlling the combustion fan 6,
A reference rotation speed setting unit 38 (reference rotation speed setting means) that sets a reference rotation speed of the combustion fan 6 corresponding to the required combustion amount of the gas burner 4, and a target rotation speed calculation unit 39 (which determines the target rotation speed of the combustion fan 6) The target rotation speed calculation means) and a proportional valve control unit 40 for controlling energization of the governor proportional solenoid valve 25.

The required combustion amount calculation unit 36 is a set temperature set by the temperature setting switch 34 of the remote controller 2 based on the feed water temperature, the water amount, the hot water temperature detected by the hot water supply thermistor 16, the water amount sensor 15, and the hot water thermistor 21. The required combustion amount of the gas burner 4 to match the hot water temperature is calculated using a predetermined arithmetic expression or the like.

In the fan control unit 37, the actual rotation speed detected by the rotation speed sensor 41 provided in the combustion fan 6 matches the target rotation speed of the combustion fan 6 obtained by the target rotation speed calculation unit 39 as described later. Combustion fan 6 to do
Feedback control the number of revolutions.

From the required combustion amount of the gas burner 4 calculated by the required combustion amount calculation unit 36, the reference rotation speed setting unit 38 should drive the combustion fan 6 according to a predetermined data table as shown in FIG. 3, for example. Find the reference speed. In this case, when the exhaust passage 32 and the air supply passage 33 are normal (when there is no blockage, etc.), the reference rotation speed in FIG. 3 is that the combustion air suitable for the required combustion amount of the gas burner 4 is supplied to the gas burner 4. It is defined as the rotation speed of the combustion fan 6 that can supply air.

The target rotation speed calculation unit 39 determines the target rotation speed of the combustion fan 6 while appropriately correcting the reference rotation speed set by the reference rotation speed setting unit 38, and applies the target rotation speed to the fan control unit 37. To explain the functional configuration in more detail, a correction value calculation unit 42 (correction value calculation means) that obtains a correction value for correcting the reference rotation speed according to the degree of blockage of the exhaust passage 32 or the air supply passage 33, A correction unit 43 (correction unit) that corrects the reference rotation speed according to the calculated correction value to obtain the target rotation speed, and a correction value calculated by the correction value calculation unit 42 immediately before the end of combustion of the gas burner 4 are stored and held. The storage unit 44 (storage unit) is included.

The correction value calculating section 42 is based on the detected energization amount obtained from the current sensor 45 for detecting the energization amount of the combustion fan 6 (the energization amount of a motor (not shown) for driving the combustion fan 6) and the exhaust passage 32 and the air supply. The degree of blockage of the passage 33 is grasped, and a correction value to be multiplied by the reference rotational speed according to the degree of blockage is obtained as follows.

That is, referring to FIG. 4, reference numeral 46 is a standard line showing a standard energization amount for each rotation speed of the combustion fan 6 when the exhaust passage 32 and the air supply passage 33 are normal, and 47 is the reference rotation. A predetermined lower limit line is set to be slightly smaller than the line 46 to determine whether or not the number needs to be corrected, and 48 indicates a case where the exhaust passage 32 or the air supply passage 33 is closed to a degree of about 60%. In the above, a line indicating the amount of electricity supplied to each rotation speed of the combustion fan 6 is indicated by 49, and an auxiliary value line 49 is previously determined based on an experiment or the like for obtaining a correction value. The line 48 is lowered as the closing of the exhaust passage 32 and the air supply passage 33 progresses.

Here, the correction value calculation unit 42 has the lower limit line 47 and the auxiliary line 49 as a data table or the like, and these data, the detected energization amount of the current sensor 45, and the rotation speed sensor 41. The correction value is obtained from the detected rotation speed, for example, every 20 ms by a predetermined arithmetic expression.

Specifically, assuming that the detected rotation speed of the combustion fan 6 is Nx and the detected energization amount is Ix, as shown in FIG. 4, the correction value calculation unit 42 first sets the lower limit line 47 and the auxiliary line 49. Currents Ia, Ib at the rotational speed Nx at
Ask for. Then, the correction value calculation unit 42 obtains the correction value H from the energization amounts Ia and Ib and the detected energization amount Ix by the following equation (1).

H = [(ΔIa / ΔIx) -1] × α + 1 (1) where ΔIa = Ia−Ib, ΔIx = Ix−Ib, and α is a constant of 1 or less.

The correction value H thus obtained from the detected energization amount of the combustion fan 6 indicates the degree of blockage of the exhaust passage 32 and the air supply passage 33, and the relationship between the correction value H and the degree of blockage is shown. As shown in FIG. 5, the degree of blockage is grasped by the correction value H. For example, the correction value H is 1.
If it is 1, it is understood that the degree of blockage of the exhaust passage 32 and the supply passage 33 is 60%. The rotation speed of the combustion fan 6 obtained by multiplying the reference rotation speed by such a correction value H has an exhaust passage 32 and an air supply passage 3 corresponding to the correction value H.
With the degree of blockage of 3, the number of revolutions is such that an appropriate amount of combustion air can be supplied to the required combustion amount of the gas burner 4.

Incidentally, the line 48 in the closed state shown in FIG. 4 is the energization amount and rotation of the combustion fan 6 in a steady state in which the ambient temperature of the combustion fan 6 has become sufficiently high by continuously burning the gas burner 4. In the state where the temperature is relatively low immediately after the combustion of the gas burner 4 is started, the sliding resistance of the combustion fan 6 is relatively large, and therefore, each of the combustion fans 6 has a relatively large sliding resistance. The energization amount at the number of rotations becomes large as shown by a virtual line 48 ', for example. Therefore, in such a state, the correction value H obtained from the equation (1) from the detected energization amount of the combustion fan 6 is
It becomes smaller than the correction value corresponding to the actual degree of blockage of the exhaust passage 32 and the air supply passage 33, and the grasped degree of clogging becomes smaller than the actual degree of clogging. In this case, the line 48 ′ is the same as the line 48 ′ as the combustion of the gas burner 4 progresses and the ambient temperature of the combustion fan 6 increases.
, And finally almost coincides with the line 48.

The correction unit 43 basically has a reference rotation speed set by the reference rotation speed setting unit 38 every moment corresponding to the required combustion amount of the gas burner 4, and the correction value calculation unit 42.
Then, the reference rotation speed is corrected by multiplying the correction value H obtained as described above to obtain the target rotation speed of the combustion fan 6. However, in this embodiment, each time the correction value calculating unit 42 obtains the correction value H (every 20 ms), the correction value H is directly multiplied by the reference rotation number to correct the target rotation number. Instead, the correction is made gradually as follows.

That is, in this embodiment, the correction unit 4
Reference numeral 3 indicates, for example, the target rotation speed while instructing the fan control unit 37 while appropriately correcting the reference rotation speed every 1 second, and at this time, the correction unit 43 causes the correction value calculation unit 42 to perform the correction every 20 ms. In a steady state in which the correction value H obtained in step 1 is continuously constant (state in which the degree of blockage is constant), the reference value is multiplied by the correction value H obtained by the correction value calculation unit 42 every second. To obtain the target speed. Then, in such a state, the degree of blockage changes, and the correction value calculation unit 4
When the correction value H obtained by 2 changes, the correction unit 43 changes the correction value by which the reference rotation speed is multiplied from the correction value H before the change toward the correction value H after the change as shown in FIG. The target number of revolutions is obtained every second while gradually changing it with a temporal change rate. In this case, the temporal change rate of the correction value multiplied by the reference rotation speed by the correction unit 43 is 0.2 in 90 seconds, for example.
(0.0022 / sec). Then, the correction unit 4
3 indicates that when the correction value to be multiplied by the reference rotational speed finally reaches the correction value H obtained by the correction value calculating unit 42, the correction value H is maintained as long as the correction value H is maintained constant thereafter.
Is multiplied by the reference rotation speed to obtain the target rotation speed.

When the correction value H obtained by the correction value calculation unit 42 is 1.0 or less, the correction unit 43 sets the correction value H to 1.0 and sets the reference rotation speed as described above. Make a correction. In this case, the reference rotation speed is not actually corrected, and the reference rotation speed is directly obtained as the target rotation speed.

Further, in this embodiment, the gas burner 4
Of the correction value H obtained by the correction value calculation unit 42 immediately before the end of the combustion (end of the hot water supply operation) of the storage unit 44.
The correction value is stored in the storage unit 44, and the correction unit 43 increases the correction value H stored and stored in the storage unit 44 at a predetermined rate at the start of the next combustion of the gas burner 4. By multiplying the reference rotation speed set by the reference rotation speed setting unit 38 by (correction value obtained by multiplying the correction value H stored and stored in the storage unit 44 by 1.1), the target rotation speed An initial value (initial rotation speed) is obtained and the fan control unit 37 is instructed to obtain it. The correction value of 1.0 is stored and held in the storage unit 44 when the water heater of the present embodiment is operated for the first time.

The proportional valve control unit 40 is detected by the rotation speed sensor 41 in order to supply the gas burner 4 with an amount of fuel gas suitable for the amount of combustion air supplied to the gas burner 4 by the combustion fan 6. The energization amount to the governor proportional solenoid valve 25 is determined according to the actual rotation speed of the combustion fan 6, and the energization control of the governor proportional solenoid valve 25 is performed by the energization amount to supply the combustion air to the gas burner 4. The gas burner 4 is burned with an amount of fuel gas suitable for the amount. in this case,
The proportional valve control unit 40 uses the exhaust passage 32 or the air supply passage 3
When there is no blockage of 3, the reference energization amount to the governor proportional solenoid valve 25 capable of supplying the fuel gas in an amount suitable for the amount of combustion air supplied at the current rotation speed of the combustion fan 6 The reference energization amount is set by a correction value H obtained by the correction value calculation unit 42, which is set by using a map or a table which is predetermined according to the actual rotation speed of the combustion fan 6 detected by the number sensor 41. By doing so, the amount of electricity supplied to the governor proportional solenoid valve 25 is determined. By energizing the governor proportional solenoid valve 25 with the energization amount thus determined, the gas burner 4 is burned with the fuel gas in an amount suitable for the amount of combustion air supplied. Then, as described above, the rotation speed of the combustion fan 6 is controlled to the target rotation speed by the fan control unit 37, and is controlled to the supply amount of the combustion air corresponding to the required combustion amount. By controlling the governor proportional solenoid valve 25 to be energized, the amount of fuel gas corresponding to the required combustion amount is eventually supplied to the gas burner 4. Since the water heater of this embodiment is of a so-called fan preceding type, the energization amount to the governor proportional solenoid valve 25 was determined as described above. However, the governor proportional directly from the required combustion amount of the gas burner 4. In the case of determining the energization amount to the solenoid valve 25 (so-called parallel type or proportional valve preceding type), it is not necessary to divide the reference energization amount to the proportional solenoid valve 25 by the correction value H.

Next, the operation of the water heater of this embodiment during hot water supply (during combustion of the gas burner 4) will be described.

When the water supply in the water supply passage 3 is started, this is detected by the control unit 7 via the water amount sensor 15,
At this time, the control unit 7 opens the original solenoid valve 24 and controls the combustion fan 6 and the gas proportional solenoid valve 25,
While supplying a predetermined amount of combustion air and fuel gas to the gas burner 4, the igniter 27 and the ignition electrode 26 ignite the gas burner 4 to start combustion. In this case, the control unit 7 performs the ignition process of the gas burner 4 after performing the pre-purge of the combustion chamber 5 by the combustion fan 6 when the hot water is supplied from the state where the water heater is stopped for a predetermined time or more, and the short time In the case where hot water is intermittently supplied at intervals, the gas burner 4 is immediately ignited as soon as the water supply passage 3 starts flowing water. The control unit 7 also confirms the ignition of the gas burner 4 via the frame rod 28.

When the gas burner 4 ignites and its combustion starts in this way, the control unit 7 causes the required combustion amount calculation unit 36 to determine the tapping temperature of the tapping pipe 11 detected by the tapping temperature thermistor 21 as the temperature of the remote controller 2. Setting switch 34
The required combustion amount of the gas burner 4 to match the set temperature set by is calculated moment by moment. Then, the reference rotation speed setting unit 38 constantly obtains the reference rotation speed of the combustion fan 6 corresponding to the required combustion amount of the gas burner 4 according to the data table shown in FIG. Further, the target rotation speed calculation unit 39 basically has a reference value according to the correction value H obtained by the correction value calculation unit 42 as described above corresponding to the degree of blockage of the exhaust passage 32 and the air supply passage 33. By correcting the reference number of revolutions set by the number-of-revolutions setting unit 38, the gas burner 4 is supplied with combustion air in an amount corresponding to the required combustion amount with the current degree of blockage of the exhaust passage 32 and the air supply passage 33. Combustion fan 6 for
The target rotation speed is calculated and the fan control unit 37 is instructed to obtain the target rotation speed. Then, the fan control unit 37 feedback-controls the rotation speed of the combustion fan 6 so that the rotation speed detected by the rotation speed sensor 41 matches the instructed target rotation speed. Also,
The proportional valve control unit 40 determines the energization amount to the gas proportional solenoid valve 25 corresponding to the rotation speed of the combustion fan 6 as described above, and energizes the gas proportional solenoid valve 25 with the determined energization amount. The fuel gas is supplied to the gas burner 4 in an amount commensurate with the amount of combustion air supplied to the gas burner 4 by the combustion fan 6.

As a result, the gas burner 4 comes to burn at the required combustion amount calculated by the required combustion amount calculation unit 36. And the hot water temperature thermistor 2 is generated by the combustion heat.
The water flowing through the heat exchanger tube 10 is heated via the heat exchanger 17 so that the detected hot water temperature of 1 matches the set temperature,
Hot water is supplied at the set temperature.

In the combustion operation of the gas burner 4 as described above, at the time of initial combustion of the gas burner 4, as described above, the energization amount at each rotation speed of the combustion fan 6 is such that the combustion of the gas burner 4 continues to burn. The correction value H calculated by the correction value calculation unit 42 is larger than that when the ambient temperature of the fan 6 is sufficiently high.
It becomes smaller than the correction value corresponding to the actual degree of blockage of the exhaust passage 32 and the air supply passage 33. In this case, as shown in FIG. 7, assuming that the correction value H corresponding to the actual degree of blockage of the exhaust passage 32 and the air supply passage 33 is Hx, the correction value H calculated by the correction value calculation unit 42 is the solid line a. As shown in, the value gradually decreases from a value smaller than Hx as the combustion of the gas burner 4 progresses, and finally becomes equal to the correction value Hx.

Therefore, if the reference rotation speed is corrected by the correction value H calculated by the correction value calculation unit 42 during the initial combustion of the gas burner 4, the target rotation speed (initial rotation speed) of the combustion fan 6 is obtained. , Its target speed is
The amount of combustion air supplied to the gas burner 4 becomes smaller than the target rotational speed obtained by correcting the reference rotational speed with the correction value Hx corresponding to the actual degree of blockage of the exhaust passage 32 and the supply passage 33. Is insufficient and combustion failure is likely to occur.

On the other hand, in the water heater of the present embodiment, as described above, the correction unit 43 ends the previous combustion of the gas burner 4 stored in the storage unit 44 at the start of combustion of the gas burner 4. The correction value obtained by multiplying the correction value H calculated by the correction value calculation unit 42 immediately before is corrected to obtain the initial rotation speed by correcting the reference rotation speed, and thereafter, the correction value to be multiplied by the reference rotation speed. Is a predetermined time change rate (0.002
(2 / sec), the reference rotation speed is corrected while gradually changing toward the correction value H calculated by the correction value calculation unit 42 to obtain the target rotation speed. In this case, in FIG. 7, for example, the degree of blockage of the exhaust passage 32 and the supply passage 33 immediately before the end of combustion of the previous gas burner 4 and the present gas burner 4 are shown.
Has the same degree of blockage during combustion, that is, the storage unit 44
Correction value Hx stored and stored in the gas burner 4 this time
Assuming that the correction value corresponding to the actual degree of blockage at the time of combustion is the same, the correction value multiplied by the reference rotation speed by the correction unit 43 is 1. 1
From the doubled value, the value gradually decreases toward the correction value H calculated by the correction value calculation unit 42 indicated by the solid line a. Then, when the correction value finally multiplied by the reference rotation speed by the correction unit 43 becomes equal to the correction value H calculated by the correction value calculation unit 42 (this finally becomes Hx), the correction value The reference rotation speed is corrected by H. In this case, in FIG. 7, assuming that Hx = 1.05 (this corresponds to the case where the degree of blockage is about 40%), the correction value by which the correction unit 43 multiplies the reference rotation speed is gradually reduced to Hx. Time is (1.1Hx-Hx) /0.0022=4
It is 7.7 seconds, and within such a time, the ambient temperature of the combustion fan 6 becomes sufficiently high, and the correction value H calculated by the correction value calculation unit 42 also matches Hx.

As a result, from the start of combustion of the gas burner 4 until the correction value multiplied by the reference rotation speed by the correction unit 43 becomes equal to the correction value H calculated by the correction value calculation unit 42. At the time of combustion, the correction unit 43
The reference rotation speed is corrected with a correction value larger than the correction value H calculated by the correction value calculation unit 42 (which is smaller than the correction value corresponding to the actual degree of blockage) to obtain the target rotation speed. Become. Then, by controlling the rotation speed of the combustion fan 6 according to the target rotation speed, the gas burner 4
A sufficient amount of combustion air can be supplied to meet the required combustion amount, and the gas burner 4 can be satisfactorily combusted. In this case, after the step in which the correction value H calculated by the correction value calculation unit 42 becomes the correction value corresponding to the actual degree of blockage, the reference rotation speed is corrected according to the correction value H to obtain the target rotation speed. Therefore, it goes without saying that good combustion of the gas burner 4 can be performed. When the ignition is re-ignited immediately after the combustion is stopped, the ambient temperature of the combustion fan 6 is sufficiently high, and if the correction is started from the value 1.1 times the correction value Hx as described above, the combustion air is It is slightly higher than the required combustion amount. However, increasing the combustion air tends to decrease CO, and there is no problem as long as the lift is not generated.

If the degree of obstruction temporarily increases due to a temporary gust of wind during the combustion of the gas burner 4, the correction value H calculated by the correction value calculation unit 42 also temporarily increases. However, since the correction value multiplied by the reference rotation speed by the correction unit 43 gradually changes with respect to the sudden change in the correction value H, the obtained target rotation speed does not change suddenly.
Therefore, the supply of the combustion air to the gas burner 4 can be stably performed without being excessively performed after the gust has stopped.

Further, in the water heater of this embodiment, the correction value H calculated by the correction value calculating section 42 is, for example, 1.2.
When the degree of blockage exceeds 80%, the control unit 7 stops the combustion operation of the gas burner 4.

Although detailed description is omitted, in the water heater of the present embodiment, the control unit 7 sets the maximum allowable combustion amount of the gas burner 4 according to the correction value H calculated by the correction value calculation unit 42. By limiting, even when the gas burner 4 burns with a large amount of heat that requires a large amount of combustion air while the exhaust passage 32 and the air supply passage 33 are blocked, the rotation speed of the combustion fan 6 is corrected. It ensures that the required amount of combustion air is supplied. Further, when the detected hot water temperature does not reach the set temperature even if the gas burner 4 is burned with the allowable maximum combustion amount, the control unit 7 reduces the flow rate of the bypass pipe 12 by the electric water amount control device 13. Thus, the detected hot water temperature can be raised to the set temperature.

In this embodiment, in order to avoid a sudden change in the rotation speed of the combustion fan 6 when the degree of blockage due to a temporary gust temporarily rises, a correction value to be multiplied by the reference rotation speed is set. Although the correction value H calculated gradually by the correction value calculation unit 42 is made to match, except for the initial stage of combustion,
The target rotation speed of the combustion fan 6 may be obtained by directly multiplying the reference rotation speed by the correction value H calculated by the correction value calculation unit 42. In this case, in the initial stage of combustion, for example, within a predetermined time from the start of combustion, the correction value H calculated from time to time by the correction value calculation unit 42 is adjusted to a degree of decrease from the correction value corresponding to the original degree of blockage. In consideration of this, the blockage is increased by a predetermined ratio, and the degree of increase is gradually decreased over time, and the target rotation speed is calculated by multiplying the reference rotation speed by the value obtained by this. It is possible to appropriately supply the combustion air corresponding to the degree.

Further, in the present embodiment, the reference rotational speed is multiplied by a value obtained by multiplying the correction value H calculated by the correction value calculation unit 42 just before the end of the previous combustion by a predetermined number (1.1 times). An initial rotation speed is obtained as an initial value of the correction value, and a correction value for multiplying the reference rotation speed from that state is used as a correction value calculation unit 4
The correction value H calculated by 2 is gradually matched. However, when the combustion fan 6 always pre-purges the combustion chamber 5 at the start of combustion, the correction value calculation unit 42 performs the pre-purging at that time. The target rotation speed may be obtained by obtaining the correction value H and multiplying the reference rotation speed with a correction value obtained by multiplying the correction value H by a predetermined value at the start of combustion.

Further, in the present embodiment, the water heater is explained as an example, but it goes without saying that the present invention can also be applied to a combustion device such as a gas type or petroleum type warm air heater.

[0057]

As is apparent from the above description, according to the present invention, the degree of obstruction of the ventilation passage is grasped based on the amount of electricity supplied to the combustion fan, and the required combustion amount of the burner is dealt with according to the degree of obstruction. In the combustion device that corrects the rotation speed of the combustion fan, the target rotation speed is corrected according to the degree of blockage of the ventilation passage that is grasped based on the detected energization amount of the combustion fan during the initial combustion after the start of combustion of the burner. The initial rotation speed that is higher than the rotation speed is calculated as the target rotation speed, and the rotation speed of the combustion fan is controlled so as to follow the calculated initial rotation speed. The burner can be satisfactorily burned by appropriately supplying the combustion air. Further, when a correction value is obtained according to the degree of blockage of the ventilation passage that is grasped based on the detected energization amount of the combustion fan, and when the target rotation speed is obtained by correcting the reference rotation speed according to the correction value,
By calculating the initial rotation speed by correcting the reference rotation speed with a correction value that is larger than the correction value according to the degree of blockage of the ventilation passage that is grasped based on the amount of electricity to the combustion fan during the initial combustion after the start of combustion of the burner. It is possible to easily calculate an appropriate initial rotation speed corresponding to the degree of blockage of the ventilation path. Further, when the reference rotation speed is corrected by the correction value obtained during combustion of the burner, the reference rotation speed is gradually changed from the state before correction so as to gradually reach the correction amount of the reference rotation speed corresponding to the correction value. When obtaining the target rotational speed while making corrections, the correction value calculated during the previous combustion of the burner is stored and held in the storage means, and is larger than the correction value stored and held in the storage means at the start of the combustion of the burner this time. When the initial rotation speed obtained by correcting the reference rotation speed with the correction value is obtained as the target rotation speed, a correction value larger than the correction value stored and held in the storage means at the start of combustion of the burner is simply obtained as the initial rotation speed. The correction value for correcting the reference rotational speed during the subsequent initial combustion of the burner is set to be larger than the correction value obtained according to the degree of blockage that is grasped from the energization amount of the combustion fan. It is possible to supply an appropriate amount of combustion air to the burner from the start of combustion of the burner, depending on the actual degree of blockage of the air passage, and such supply of combustion air is simple at the start of combustion of the burner. It can be easily performed only by performing various processes. At the same time, it is possible to eliminate a situation in which the rotational speed of the combustion fan temporarily changes suddenly due to a temporary gust, and it is possible to stably supply an appropriate amount of combustion air to the burner. it can.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a water heater including a combustion device according to an example of the present invention.

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

FIG. 3 is a diagram for explaining the operation of the water heater of FIG.

FIG. 4 is a diagram for explaining the operation of the water heater of FIG.

FIG. 5 is a diagram for explaining the operation of the water heater of FIG.

6 is a diagram for explaining the operation of the water heater of FIG.

7 is a diagram for explaining the operation of the water heater of FIG.

[Explanation of symbols]

4 ... Burner, 5 ... Combustion chamber, 6 ... Combustion fan, 37 ... Fan control means, 38 ... Reference rotation speed setting means, 39 ... Target rotation speed setting means, 42 ... Correction value calculating means, 43 ... Correction means, 44 ... Storage means, 45 ... Current sensor (energization amount detection means).

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Kitagawa Hideki Kitagawa 2-26 Fukuzumi-cho, Nakagawa-ku, Nagoya, Aichi Rinnai Co., Ltd. (56) Reference JP-A-8-152131 (JP, A) JP-A-7 -127853 (JP, A) JP-A-7-127854 (JP, A) JP-A-3-186113 (JP, A) JP-A-6-2844 (JP, A) Actual development Sho 62-136743 (JP, U) ) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F23N 5/24 F23N 3/08 F23N 5/18

Claims (3)

(57) [Claims] 1. A burner housed in a combustion chamber, a combustion fan for supplying combustion air to the burner, and a burner for supplying to the burner an amount of combustion air corresponding to a required combustion amount of the burner. Reference rotation speed setting means for setting the reference rotation speed of the combustion fan, energization amount detection means for detecting the energization amount of the combustion fan during combustion of the burner, and the combustion fan of the combustion fan obtained by the energization amount detection means. Based on the detected energization amount, grasp the degree of blockage of the air passage for performing air supply / exhaust of the burner, correct the reference number of revolutions according to the degree of blockage, and obtain the target number of revolutions of the combustion fan. In a combustion device comprising a speed calculation means and a fan control means for controlling the rotation speed of the combustion fan so as to follow the target rotation speed calculated by the target rotation speed calculation means, the target rotation speed calculation means Is characterized in that at the time of initial combustion after the start of combustion of the burner, an initial rotation speed larger than a target rotation speed obtained by correcting the reference rotation speed according to the degree of blockage of the air passage is obtained as the target rotation speed. Combustion device. 2. The target rotation speed calculation means calculates a correction value for obtaining a correction value for correcting the reference rotation speed in accordance with the degree of blockage of the air passage that is grasped based on the detected energization amount of the combustion fan. And a correction unit that corrects the reference rotation speed according to the correction value calculated by the correction value calculation unit to obtain the target rotation speed.
During the initial combustion after the start of combustion of the burner, the reference rotation speed is corrected by a correction value larger than the correction value of the reference rotation speed according to the degree of blockage of the air passage, and the initial rotation speed is obtained. The combustion device according to claim 1. 3. A storage unit for storing and holding the correction value calculated by the correction value calculation unit during the previous combustion of the burner, the correction unit including the correction value calculation unit during the combustion of the burner. When the reference rotation speed is corrected by the correction value obtained by, the reference rotation speed is gradually corrected from the state before correction so as to gradually reach the correction amount of the reference rotation speed corresponding to the correction value. In addition to obtaining the target rotation speed, at the start of the current combustion of the burner, an initial rotation speed obtained by correcting the reference rotation speed with a correction value larger than the correction value stored and held in the storage means is obtained as the target rotation speed. The combustion device according to claim 2, wherein