JP3108342B2 - 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 apparatus, and can be used as a heat source for a water heater, a clothes dryer, a heater, and the like.

[0002]

2. Description of the Related Art As a combustion apparatus of this type, there is, for example, one proposed in Japanese Patent Application No. Hei 6-328191, which is constructed as shown in FIG. The intake port (12) at the upstream end of the air supply path (11) that supplies air to the combustion chamber (3) is the main body case (1).
And the air inlet (12) is covered with a removable filter (13).
An air supply fan (2) is provided in (11). A burner (3) is provided in the combustion chamber (3) supplied with air from the air supply passage (11).
1) is accommodated, and a heat exchanger (4
1) and the exhaust stack (5) are arranged in this order.

On the other hand, there is an invention of Japanese Patent Application No. 7-140403 already proposed as an invention relating to the combustion control of the combustion apparatus, and the invention relating to the combustion control can be applied to the combustion apparatus having the structure shown in FIG. . When the invention relating to the combustion control is used, for example, when the clogging of the filter (13) progresses in the combustion apparatus as shown in FIG. 6, the burner is corrected by correcting the rotation speed of the air supply fan (2). (31) can be completely burned. That is, in this case, as shown in FIG. 8, the calculation is determined based on the flow rate of the water flowing into the heat exchanger (41), the water temperature thereof, and the set temperature set by a hot water temperature setter (not shown). Burner (31)
The reference rotation speed of the air supply fan (2) determined by the required combustion amount (a speed different for each required combustion amount) is stored in the reference rotation speed setting means (T). Then, the shortage of air supply caused by the increase in the degree of clogging of the filter (13) is determined by the rotational resistance of the fan (2) (if the clogging of the filter (13) progresses, the fan (2) tends to run idle). The rotational speed of the air supply fan (2) is determined based on the current value of the fan motor (21), which changes with the rotation resistance, and a correction value for correcting the rotational speed of the air supply fan (2) based on the current value. The calculation is repeated in a short time cycle in (I). Then, the latest correction value output from the correction value determination means (I) is stored in the correction value storage means.
(J) and corrects the reference rotation speed (stored in the reference rotation speed setting means (T)) based on the correction value stored in the correction value storage means (J). The calculation for obtaining the proper rotation speed of the air supply fan (2) is executed by the proper rotation speed setting means (C). The output of the proper rotation speed setting means (C) is applied to the fan control means (H), and the rotation speed of the air supply fan (2) is controlled by the fan control means (H). If the filter (13) becomes clogged and the air supply fan (2) can supply only a small amount of air to the downstream side, the air supply fan (2) approaches an idling state and its rotational resistance decreases. Therefore, even when the motor (21) is operating at the same rotation speed, the current flowing through the motor (21) is small, and the degree of clogging of the filter (13) can be grasped.

According to the above, the correction value of the rotation speed of the air supply fan (2) is stored in the correction value storage means (J) even after the hot water supply is stopped. In this case, the air supply fan (2) is controlled so as to have an appropriate rotational speed determined by using the stored correction value. Therefore, when the invention of the above control is applied to the combustion device having the structure of FIG. 6, even if the degree of clogging of the filter (13) is slightly increased, the air supply fan (2)
Since the correction for increasing the rotation speed of the burner (31) is performed, the disadvantage that the amount of combustion air supplied to the burner (31) is insufficient can be avoided.

[0005]

However, if clogging of the filter (13) progresses, there is a possibility that the filter (13) will be cleaned while the combustion is stopped. Therefore, when the hot water supply operation is performed after the filter cleaning, according to the above, the current rotation speed is obtained based on the correction value of the rotation speed of the air supply fan (2) stored at the end of the previous combustion. Therefore, there has been a problem that the ignition operation to the burner (31) is executed in a state where the combustion air is extremely excessive, and an ignition mistake is likely to occur.
Although the above description has been made by taking a water heater as an example, a combustion device such as a clothes dryer has the same problem as described above.

The invention of claim 1 has been made in view of the above point. "The burner is driven by the combustion air sucked by the air supply fan (2) through the air supply path (11) having the filter (13). A combustion device for burning (31), wherein the burner (31)
A correction value for correcting a reference rotation speed of the air supply fan (2), which is predetermined according to the required combustion amount, according to the degree of clogging of the filter (13),
Correction value determination means (I) repeatedly determined during the operation of (2)
Correction value storage means (J) for storing the correction value output from the correction value determination means (I), and correcting the reference rotational speed based on the correction value stored in the correction value storage means (J). A proper rotation speed setting means (C) for determining an appropriate rotation speed of the air supply fan (2), thereby providing the air supply fan (2) at the appropriate rotation speed output by the appropriate rotation speed setting means (C). 2) A combustion device that operates such that a burner (31) can be smoothly ignited even if the filter (13) is cleaned during combustion stoppage. .

[0007]

Means for Solving the Problems The invention of claim 1 for solving the above-mentioned problems will be described with reference to FIG. 7. The invention of claim 1 is described as follows. Cleaning reference value storage means (K) for storing as a cleaning reference value the same value as the correction value which is output by the correction value determining means (I) in the case of clogging; and storing the cleaning reference value and the correction value. A comparing means (L) for comparing the correction values stored by the means (J) and outputting an initial inspection signal when the latter correction value is large is provided, and when the combustion start operation is performed, the air supply fan (2) is turned on. If the comparison means (L) is outputting the initial check signal at this time while maintaining the operating state, the output of the correction value determination means (I) at this time is stored in the correction value storage means (J). After that, the burner (31) is ignited. ' You.

According to the present invention, when the clogging of the filter (13) progresses and reaches the level required for cleaning, that is, the air supply fan stored in the correction value storage means (J).
When the combustion start operation is performed when the rotation speed correction value of (2) has reached the cleaning reference value stored in the cleaning reference value storage means (K), the filter (13) is cleaned. A determination is made as to whether or not it has occurred. That is, in such a case, burner
Before the combustion of (31), the air supply fan (2) is rotated, and the air supply fan (2) is rotated according to the degree of clogging of the filter (13).
The operation of (2) for obtaining the correction value of the reference rotational speed is executed by the correction value determination means (I), and the correction value is stored in the correction value storage means (J). Therefore, when the clogged filter (13) is cleaned while the combustion of the burner (31) is stopped, a correction value suitable for the state of the cleaned filter (13) is stored in the correction value storage means ( J), the reference rotation speed of the air supply fan (2) is corrected based on this correction value, and then the burner (31) is ignited.

Therefore, unlike the case where the rotational speed of the air supply fan (2) is corrected based on the correction value stored in the correction value storage means (J) at the end of the previous combustion, the combustion start operation is performed immediately after the filter cleaning. The ignition operation is not executed in an extremely excessive air condition even when the operation is performed.

[0010]

According to the present invention, even when the combustion start operation is performed immediately after the cleaning of the filter, the ignition operation is not executed in an extremely excessive air state, so that a smooth ignition operation is ensured without occurrence of an ignition mistake. Only when the correction value stored in the correction value storage means (J) has reached the required cleaning level, it is confirmed whether or not the filter (13) has been cleaned. Filter (1
If 3) is not clogged, the burner (31) can be ignited early.

[0011]

Next, an embodiment of the present invention will be described. This embodiment is applied to a water heater having a structure as shown in FIG. As already mentioned,
The intake port (12) located at the upstream end of the air supply passage (11) is the main body case
It is open to the front of (1) and the air inlet (12) is covered with a removable filter (13).
3) is a rectangular frame (130) and a wire mesh (131) stretched over it
It is composed of At the downstream end of the air supply passage (11), an air supply fan (2) composed of a rotating blade (22) and a motor (21) is provided, and the motor (21) has a rotating fan. A speedometer (23) for outputting a speed (the number of rotations per unit time) is provided. A combustion chamber (3) containing a burner (31) is connected to the discharge side of the air supply fan (2), and the downstream side of the combustion chamber (3) is discharged from a portion where the heat exchanger (41) is provided. Cylinder (5)
Is connected to. The heat exchanger (41) is provided with heat absorbing fins (4
3) It consists of a group and a water pipe (44) penetrating it,
The water pipe (44) extends from the water inlet (48) to the appliance to the hot water outlet (4).
It constitutes a part of the water channel (4) leading to 9). And
In the vicinity of the upstream end of the heat exchanger (41), a flow meter (42) and a water temperature sensor (45) on the downstream side thereof are provided, and a hot water outlet (49) on the downstream end of the water passage (4). ) Is connected to a tap water tap (46). Further, an ignition device (30) is disposed near the burner (31), and a gas circuit (32) to the burner (31) has a main valve (34) and a gas proportional valve on the downstream side thereof. (33) is provided.

The air supply fan (2) and the like are connected to a control device (6) shown in FIG. 3 incorporating a microcomputer. That is, the rotation speed of the motor (21) for the air supply fan (2) is controlled by the control device (6), and the speedometer (23) detects the rotation speed of the motor (21). The output is monitored by the control device (6). The output of the ammeter (25) for detecting the magnitude of the current flowing through the motor (21) is monitored by the control device (6), whereby the rotational resistance acting on the motor (21) is determined. The degree of clogging of the filter (13) can be detected. The control device (6) includes a gas proportional valve (33) and a main valve (34) inserted in a gas circuit (32) to a burner (31), and further includes the ignition device (30).
An igniter (30) for performing an ignition operation is connected to the igniter to control these operations. Further, a remote control device (7) provided in a kitchen or the like and having a hot water temperature setting device (71) and an operation switch (72), a flow meter (42) inserted in a water passage (4), and a water temperature sensor ( The output of 45) is applied to the control device (6).

The microcomputer incorporated in the control device (6) stores a control program having the contents shown in the flow charts of FIGS. 1 and 2. Hereinafter, the actual operation of the water heater according to the present embodiment will be described. Will be described with reference to FIGS. When the operation switch (72) provided on the remote operation device (7) is operated, the microcomputer in the control device (6) starts to operate, and in step (ST1) in FIG. 1, the hot water supply built in the microcomputer is stopped. Time judgment timer
Set the output of (T1) to "300 seconds".

Next, in step (ST2), the output of the flow meter (42) is monitored. If the output is equal to or higher than the set value, it is determined that the tap water tap (46) has been opened, and in step (ST3), the air supply fan is turned on. (2) is rotated at an initial rotation speed n ₀ . Next, step (ST4)
Then, it is determined whether or not the correction value H0 of the rotation speed of the air supply fan (2) has not reached the required cleaning level. The correction value H0 is determined by the method described later using the output of the ammeter (25) as described above.
(13) is set to a value of "1" indicating that there is no clogging. The cleaning required level is set to a value larger than “1” indicating that there is no clogging.
In this embodiment, it is set to "1.2", which corresponds to the case where the degree of clogging of the filter (13) is 80%. In the present embodiment, a memory in the microcomputer for storing the value of “1.2”
A function unit in the microcomputer which corresponds to the cleaning reference value storage means (K) of the invention and judges whether or not the correction value H0 has reached the required cleaning level in the step (ST4). This corresponds to the comparing means (L) of the first invention.

Next, if it is determined that the correction value H0 is less than the required cleaning level "1.2" and the clogging of the filter (13) is not large, then in step (ST5), a hot water supply stop time determination timer is determined. Judging the time that (T1) is outputting, this is 3
If it is longer than 00 seconds, it is determined that the hot water supply operation has been performed after being left in the appliance stopped state for a long time.
In order to perform the air purging of (3), a wait of 3 seconds is executed in step (ST6) with the air supply fan (2) operated.

When the air purge for three seconds is completed, the operation of igniting the burner (31) is performed in step (ST11) of FIG. That is, the main valve (34) inserted into the gas circuit (32) is opened and the ignition device (30) is driven, thereby burning the burner (31). Then, when the water flowing into the water passage (4) passes through the heat exchanger (41), the burner (31)
The hot water flows out of the hot tap (46) and the hot water supply operation proceeds. In this case, the required combustion amount of the burner (31) depends on the flow rate in the water passage (4) detected by the flow meter (42), the water temperature detected by the water temperature sensor (45), and the hot water temperature setting device.
The feedforward control which is calculated from the set temperature and the like by (71) is executed. When the required combustion quantity of the burner (31) is calculated, the reference each combustion amount of the rotation speed n _e (burner (31) of the air supply fan (2) which is predetermined in accordance with the combustion amount in response the control unit is stored in the microcomputer (6) table) is output from the microcomputer, the air supply fan in this reference rotational speed n _e (2) is made to drive. Incidentally, the reference rotational speed n _e is, in the conditions that the filter (13) is not clogged burner
Combustion air necessary to completely burn (31) is supplied to the burner (3).
This is the rotation speed of the air supply fan (2) necessary to supply it to (1).

Next, in step (ST12), a waiting time of one second is executed. After that, in step (ST13), the reference rotation speed n is set according to the degree of clogging of the filter (13).
_An operation for obtaining a correction value for correcting _e is executed. Specifically, as shown in FIG. 4, the motor (2) for the air supply fan (2)
The current flowing through 1) (the output of the ammeter (25)) is IX and the speedometer (2
Assuming that the rotation speed of the air supply fan (2) detected by 3) is NX, the microcomputer calculates a standard line indicating the relationship between the fan rotation speed and the current of the motor (21) when the filter (13) is not clogged. L1 and the auxiliary lines L2 are used, and the currents Ia and Ib at the rotation speed NX in these lines are used.
Ask for. Then, using these Ia and Ib and the current IX actually detected by the ammeter (25), the necessary correction value H (which is stored again as the correction value H0) is obtained from the following equation.

H = [((ΔIa / ΔIX) −1) × α + 1] where ΔIa = Ia−Ib, ΔIX = IX−Ib, and α are experimentally obtained with a constant of 1 or less. In the present embodiment, the functional units (steps (ST13), (ST24), (ST8)) in the microcomputer for calculating the necessary correction value H are described.
Is equivalent to the correction value determining means (I) according to the first aspect of the present invention.

The relationship between the rotation speed of the air supply fan (2) and the current of the motor (21) shown in the graph of FIG. 4 is stored in the microcomputer in advance in the form of a function or a table. The necessary correction value H obtained from the current flowing through the motor (21) for the air supply fan (2) in this manner is equal to the value of the filter (1).
3) indicates the tendency of the degree of clogging, and the relationship between the necessary correction value H and the degree of clogging of the filter (13) is as shown in FIG. For example, if H is 1.2, it is determined that the degree of clogging of the filter (13) is 80%, and this value is set to the cleaning required level in the present embodiment.

Next, in step (ST14), "1" is used to determine whether the degree of clogging of the filter (13) has changed.
The filter (13) is not clogged at all and the two are equal, and the flow rate in the water passage (4) detected by the flow meter (42) is compared. a water temperature sensor (45) temperature and water temperature setter detects (71) a reference predetermined according to the required amount of combustion burner (31) which is calculated from the set temperature or the like rotational speed n _e to the correction value A calculation for correcting the rotation speed of the air supply fan (2) is performed by multiplying by H0, and the motor (21) for the air supply fan (2) is rotated according to the calculation result (step (ST15)). . In the present embodiment, functional unit within a microcomputer for multiplying the correction value H0 to the reference rotation speed n _e corresponds to the correction value storing means of the invention of claim 1 (J).

Next, in step (ST16), it is determined whether or not the tap faucet (46) is closed based on the output of the flow meter (42). If the tap is closed, the burner (31) is extinguished and the water is supplied. After stopping the air fan (2) and setting the hot water supply stop time determination timer (T1) used to determine the time until the next hot water supply start operation is performed to "0", the control operation is performed in steps. Return to the initial step of (ST1).

On the other hand, in the above step (ST16), the tap water tap (46)
Is determined to be maintained in the open state, a step of waiting for one second is executed, and then H is calculated again (ST12) (S12).
The control operation is returned to T13). If the degree of clogging of the filter (13) changes and H does not match the correction value H0, the process branches from step (ST14) to step (ST21),
Hereinafter, the operation of controlling the speed of the air supply fan (2) to the rotational speed according to the changed degree of clogging of the filter (13) starts.

In this embodiment, even when the degree of clogging of the filter (13) changes, the rotation speed of the air supply fan (2) is gradually changed without sudden change. This is to prevent the rotational speed of the air supply fan (2) from fluctuating suddenly due to a temporary cause such as when a gust crosses the filter (13). For this reason, in this embodiment, the rotation speed of the air supply fan (2) is controlled so as to reach the target rotation speed in 90 seconds. That is, step (S
At T22), the value of the necessary correction value H is stored again as the correction value H0, and then at step (ST23), the value of I is increased by "1".
Next, at step (ST24), H1 = ((((correction value H0-
H) × I / 90) + correction value H0), the required amount of correction of the rotation speed of the air supply fan (2) (correction value H
0 - needed to perform the operation of changing only one 90 minute correction value H), rotating the motor (21) of the air supply fan (2) for a rotational speed obtained by multiplying the reference rotation speed n _e in the H1. Next, the value of I is determined in step (ST25). If the value is 90 or less, a waiting time of one second is executed in step (ST26), and then the necessary correction value H is calculated again in step (ST27). When the value of the necessary correction value H is equal to the correction value H0 stored again in step (ST23), and the degree of clogging of the filter (13) has not changed during the time waiting in step (26). Increases the relative value of I by "1" until it reaches "90" (until 90 seconds have elapsed).
(ST23) to Step (28) are repeated, whereby the rotation speed of the air supply fan (2) gradually approaches the target rotation speed.
When I becomes "90", the process proceeds from step (ST25) to step (ST29), and the final value of HI is stored again as the correction value H0. If the degree of clogging of the filter (13) does not change during the above 90 seconds and the value of H does not change again, the final value of HI becomes equal to the necessary correction value H. On the other hand, if the amount of dust or the like attached to the filter (13) suddenly increases during the control time of 90 seconds, or if a gust acts on the filter (13), the process proceeds from step (ST28) to step (ST29). After that, the control for correcting the rotation speed of the air supply fan (2) is discontinued, and the control operation returns to the step of waiting for the time of step (ST12), and the hot water supply operation proceeds.

Next, a case where the hot water supply operation is performed again after the hot water supply stop operation will be described. The flow meter (4
The output of 2) drops below the set value,
When the closing operation of the tap faucet (46) is confirmed in (ST16), the control operation is shifted from the step (ST17) to the step (ST2) of FIG. Operations are monitored.

When the hot water supply operation is restarted by opening the tap faucet (46), the correction value H0 is equal to or higher than "1.2" which is the level required for cleaning the filter (13) in step (ST4). In this case, it is highly possible that the filter (13) is cleaned during the stop of hot water supply.In such a case, the current flowing to the motor (21) for the air supply fan (2) is stabilized in step (ST7). Wait for 7 seconds to wait Next, after calculating the necessary correction value H described in step (ST8), the process proceeds to step (ST9), and the value of the required correction value H is stored again as the correction value H0. The control operation following step (ST11) is executed. On the other hand, if the correction value H0 is equal to or less than the cleaning required level when executing the step (ST4), the step (ST4) is performed as described above.
5) When (ST6) is executed and the hot water supply stop time determination timer (T1) is equal to or shorter than 300 seconds, that is, when the hot water supply is stopped (the hot water supply stop time determination timer (T1) 30) until the tapping operation is performed.
If it is less than 0 second, the burner (31) is ignited without purging the air in the combustion chamber (3) (step (S
(Ignition of the burner (31) without performing T6)).
On the other hand, when the hot water supply stop time determination timer (T1) is 300 seconds or more, the ignition operation to the burner (31) is performed after performing the air purge for 3 seconds in step (ST6).

As described above, according to the above, when the degree of clogging of the filter (13) progresses and there is a possibility that the filter (13) may be cleaned while the hot water supply is stopped, whether or not the filter (13) is cleaned is determined. And the correction value H0 at this time is used thereafter, so that the air-gas mixture does not become excessively air-rich during the ignition operation of the burner (31), and the burner (31)
The ignition operation proceeds smoothly. Also, only when the degree of clogging of the filter (13) has progressed to a certain level,
Because it is determined whether the filter (13) has been cleaned,
When the filter (13) is not clogged and there is little possibility of being cleaned, the control for determining the correction value H0 is not performed, and in such a case, the burner (31) is ignited early.

In the above-described embodiment, the difference between the actual current value flowing through the motor (21) and the current value that should be passed (when the filter (13) is not clogged) is determined based on the difference between the current value flowing through the motor (21) and the current value flowing through the filter (13). Although it was determined to determine the degree of clogging, irradiating the wire mesh filter (13) with ultrasonic waves or light rays, it is also possible to determine the degree of clogging of the filter (13) based on its transmittance or reflectance. good.

[Brief description of the drawings]

FIG. 1 is a flowchart for controlling a water heater according to an embodiment;

FIG. 2 is a flowchart for controlling a water heater according to the embodiment;

FIG. 3 is an explanatory diagram of a control circuit.

FIG. 4 is a graph showing the relationship between the rotation speed of the air supply fan (2) and the current flowing through the motor (21).

FIG. 5 is a graph showing a relationship between a degree of clogging of a filter (13) and a correction value.

FIG. 6 is a sectional view of the water heater according to the embodiment;

FIG. 7 is a conceptual explanatory view of the invention of claim 1;

FIG. 8 is an explanatory view of the prior art.

[Explanation of symbols]

 (2) ・ ・ ・ Air supply fan (13) ・ ・ ・ Filter (31) ・ ・ ・ Burner (C) ・ ・ ・ Appropriate rotation speed setting means (I) ・ ・ ・ Correction value determination means (J) ・ ・ ・Correction value storage means

Claims (2)

(57) [Claims] 1. A combustion device for burning a burner (31) by combustion air sucked by an air supply fan (2) through an air supply passage (11) having a filter (13), wherein the burner (31) 31) the reference rotation speed of the air supply fan (2) which is predetermined according to the required combustion amount of the filter (1).
3) a correction value determining means (I) for repeatedly determining a correction value for correcting in accordance with the degree of clogging during the operation of the air supply fan (2), and a correction value determining means (I). The correction value storage means (J) for storing a correction value to be output; andthe air supply fan by correcting the reference rotational speed based on the correction value stored in the correction value storage means (J).
(2) Proper rotation speed setting means for determining the proper rotation speed
(C), wherein the air supply fan (2) is operated at the appropriate rotation speed outputted by the appropriate rotation speed setting means (C). A cleaning reference value storage means (K) for storing, as a cleaning reference value, the same value as the correction value which is output by the correction value determining means (I) when clogging is performed; and the cleaning reference value and the correction value Comparing means (L) for comparing the correction values stored in the storage means (J) and outputting an initial inspection signal when the latter correction value is large, and when the combustion start operation is performed, the air supply fan (2) If the comparison means (L) is outputting the initial inspection signal at this time, the output of the correction value determination means (I) at this time is stored in the correction value storage means (J). After that, the ignition operation for the burner (31) is performed. Apparatus. 2. The correction value determining means (I) includes a filter (13).
The combustion apparatus according to claim 1, wherein the correction value of the degree of clogging is determined based on a current value of a motor (21) for an air supply fan that changes according to the degree of clogging.