JP3393936B2 - 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 burner combustion type combustion apparatus such as a water heater and a bath kettle.

[0002]

2. Description of the Related Art FIG. 6 shows a schematic configuration of a general water heater as a combustion device. In the figure, the instrument body 2 is housed in the instrument case 1. A burner 4 is installed below the combustion chamber 3 of the instrument body 2, and a combustion fan 5 for supply and exhaust is installed below the burner 4. A nozzle 6 is arranged opposite to the gas inlet of the burner 4, and fuel gas is supplied to the nozzle 6 via a gas supply passage 7. An electromagnetic valve 8 for opening and closing the passage and a proportional valve 10 for controlling the gas supply amount to the burner 4 by the opening amount are incorporated in the gas supply passage 7.
The combustion fan 5 has a hall I for detecting the fan speed.
A fan rotation detection sensor 21 such as C is provided.

A hot water supply heat exchanger 11 is installed above the combustion chamber 3, and a water supply pipe 12 is provided at the inlet side of the hot water supply heat exchanger 11.
Is connected, and the hot water supply pipe 13 is provided on the outlet side of the hot water heat exchanger 11.
Are connected. The water supply pipe 12 is provided with a water inlet temperature sensor 14 for detecting the water supply temperature and a flow rate sensor 15 for detecting the water inlet flow rate, and a hot water outlet temperature sensor 16 for detecting the hot water supply temperature is provided on the hot water supply pipe 13 side. .

Between the upstream side and the downstream side of the flow passage extending from the combustion fan 5 to the atmosphere through the exhaust passage 36, in this figure,
A communication passage 24 is provided between the air chamber below the burner 4 and the combustion chamber 3 above the burner 4, and the amount of air supplied from the combustion fan 5 to the burner 4 side is directly provided in this communication passage 24. Alternatively, an air volume detecting means 23 for indirectly detecting is provided. Various well-known sensors such as a differential pressure sensor, a heat ray heater type wind speed sensor, a karma vortex type wind speed sensor, and a propeller rotating type air flow sensor can be used as the air flow rate detecting means.

The combustion operation of this kind of equipment is carried out by a control device 17, which normally has a remote controller (not shown) for setting the hot water supply temperature and displaying the set temperature. ) Is connected. As shown in FIG. 7, the combustion device 17 includes a combustion control unit 30 and a fan control unit 31. The combustion control unit 30 is provided with control characteristic data of the combustion capacity and the proportional valve current (fuel gas supply amount) as shown in FIG. 8A, and is required every moment during the combustion operation. The combustion capacity is calculated, the proportional valve current is controlled so that the required combustion capacity is obtained, and the combustion heat quantity of the burner 4 is controlled.

The fan controller 31 is provided with characteristic data of the relationship between the combustion capacity and the air volume as shown in FIG. 8B, and the air volume commensurate with the required combustion capacity calculated by the combustion controller 30 is given. The fan rotation speed of the combustion fan 5 is controlled so that it can be obtained. There is a relationship between the fan rotation speed and the air volume as shown in FIG. 8C, and the target air volume can be obtained by controlling the fan rotation speed.

In FIG. 6, 18 is an igniter electrode for igniting fuel gas, 20 is a frame rod electrode for detecting the flame of the burner 4, 22 is a louver functioning as an intake port provided on the wall surface of the instrument case 1, Reference numeral 19 is a punching metal (provided as necessary) for equalizing the wind pressure toward the burner 4.

In this type of equipment, when a hot water tap (not shown) provided at the tip side of the hot water supply pipe 13 is opened, the water supply pipe 12
When water flows in from the inside and the flow of this water is detected by the flow rate sensor 15, as shown in FIG. 9, the control device 17 rotates the combustion fan 5. Then, when the air volume detecting means 23 detects the slow ignition air volume (air volume of the slow ignition level), the solenoid valve (gas valve) 8 and the proportional valve 10 are opened to cause the slow ignition gas supply operation state (the flame extinguishes). The gas amount is supplied in a range in which the gas amount is narrowed and supplied), and the igniter electrode 18 is driven to ignite. After the flame rod electrode 20 detects the flame and after ignition, the slow ignition operation state is maintained for a predetermined short time Δt, and then feedforward and feedback are used in combination to proportionally control the valve opening drive current of the proportional valve 10. The rotation control of the combustion fan 5 is performed so as to supply the gas supply amount (the valve opening amount of the proportional valve 10) and the air corresponding to the gas supply amount so that the hot water outlet temperature becomes the set temperature.

When the hot water is used and the hot water tap is closed, the passage of water to the hot water supply heat exchanger 11 is stopped, and when the stop of the flow of water is detected by the signal from the flow rate sensor 15, the solenoid valve is activated. 8 is closed, and thereafter, when the post-purge period for discharging the exhaust gas in the combustion chamber 3 has elapsed, the rotation of the combustion fan 5 is stopped to prepare for the next hot water discharge.

[0010]

By the way, as shown in FIG. 9 (b), when the burner 4 is ignited, a large pressure fluctuation is instantaneously generated due to combustion expansion, and the air flowing in the appliance is breathed. Then, the air volume detected by the air volume detection means 23 suddenly and suddenly decreases at the portion a. Then, the fan control unit 31 tries to maintain the slowly ignited air volume, and as shown in FIG. 9A, the voltage applied to the combustion fan 5 is instantaneously increased at the portion b, so that the air volume is C this time. There is a problem that the flame rapidly extinguishes in the area of, and the combustion performance deteriorates, and in an extreme case, the flame disappears due to the increase of the air volume.

As a combustion device provided with a means for preventing the extinction of the flame upon such point ignition, Japanese Patent Laid-Open No. 2-1
Japanese Patent No. 61212 is disclosed. This is shown in Figure 5.
As shown in, after a pre-purge time T _1, a predetermined T
Until ₂ hours have passed, regardless of the detected air volume, the fan drive voltage is fixed to a constant value, and the instantaneous decrease in the detected air volume during point ignition occurs as shown in part a of FIG. 5 (b). Even so, it is intended to prevent the flame from extinguishing by eliminating a sharp increase in the fan drive voltage as indicated by the broken line in FIG.

However, at the time of point ignition of the burner, as shown in FIG. 4, the actual air volume also decreases as shown by the broken line in the figure in the period in which the sensor output of the air volume detecting means sharply decreases. As in the conventional example shown in FIG. 5, if the fan drive voltage is fixed to a constant value, combustion air that compensates for the decrease in the actual air volume cannot be obtained, so the air volume tends to be insufficient and combustion performance is It becomes worse, and troubles such as frequent occurrence of flame extinction during the slow ignition period occur.

Further, in the system in which the ignition is always waited until the pre-purge time T ₁ elapses, it takes a long time until the ignition, so that the hot water supply cannot be used promptly. Generally, in hot water heaters and the like, post-purge is widely performed in which the combustion fan is continuously rotated for a predetermined period of time after combustion is stopped to discharge exhaust gas in the combustion chamber. If the gas is discharged within the post-purge period, a long pre-purge time T ₁ as in the conventional example shown in FIG.
The ignition operation can be started without waiting for. Further, even when a cold start is performed after a long time has passed after the combustion is stopped, the ignition operation can be immediately started without requiring the pre-purge.

The present invention has been made in view of the above circumstances, and an object thereof is to instantaneously increase the air volume due to an abnormal increase in the fan drive voltage due to fluctuations in the air volume detection during the slow ignition period, thereby deteriorating the combustion performance. To provide a combustion device capable of quickly starting a combustion operation by performing point ignition within a short time after an ignition command when a flame does not extinguish and a pre-purge is not required. .

[0015]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention is provided with an air volume detection means for detecting the actual air volume of the combustion air supplied to the burner by the supply / exhaust combustion fan, and the combustion air suitable for the combustion volume is based on the air volume detection value of this air volume detection means. In the combustion apparatus including the fan control unit that controls the operation amount of the combustion fan so as to obtain the amount, in the slow ignition combustion at the time of point ignition of the burner, the slow flow amount of the air flow detected by the air flow detection means is given in advance. The slow ignition air volume stability determination unit that determines the air volume stability point at which the air volume stabilizes after entering the range, and the operation amount of the combustion fan at the time when the air volume stability point is determined by this slow ignition air volume stability determination unit is the reference operation amount. And a slow ignition operation amount limiting section provided with a limiter for limiting the slow ignition operation amount range of the fan control section based on the reference operation amount.

Further, the burner having the above-mentioned configuration is composed of a burner of a capacity switching type for switching the combustion capacity by switching the combustion surface, and the slow ignition manipulated variable limiting section responds to the switched combustion capacity every time the combustion capacity is switched. It is also a feature of the present invention that a different limiter is provided.

[0017]

In the present invention having the above-described structure, the combustion fan is rotationally driven so as to reach the level of the slow ignition air volume at the time of point ignition of the slow ignition control of the burner, and the air volume detection means detects the fan air volume at this time. Then, when it is confirmed that the detected air volume is within the slow ignition air volume range, the slow ignition air volume stability determination unit, based on the air volume intake information of the air volume detection means, stabilizes the air volume within the slow ignition air volume range. Confirm the point. When this air flow stable point is determined, the operation amount of the combustion fan at that time (for example, fan applied voltage)
Is used as a reference operation amount, and a limiter that limits the slow ignition operation amount range of the combustion fan (combustion fan applied voltage control range) with this reference operation amount as a reference is given to the fan control unit by the slow ignition operation amount limiting unit. The fan control unit controls the slow ignition operation amount of the combustion fan within the range of the given limiter.

Since the limiter is provided, even if the detected air volume of the air volume detection means suddenly decreases due to combustion expansion at the time of point ignition of the burner, the operation amount of the combustion fan exceeds the limiter. Since there is no problem, there is no problem that the air volume momentarily increases and the flame disappears, and since the operation amount of the combustion fan can be controlled to increase or decrease within the limiter range, the air volume will change due to the breathing phenomenon during point ignition. Even if it decreases, it is possible to increase the manipulated variable to compensate for this decrease within the range of the limiter, thereby eliminating the shortage of the combustion air amount and improving the combustion performance during slow ignition combustion.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same names as those in the conventional example are designated by the same reference numerals, and the duplicate description thereof will be omitted. The combustion apparatus of this embodiment is intended for a water heater having the same structure as that shown in FIG. This embodiment is different from the conventional example in that the controller 17 is provided with a unique air volume control means for controlling the air volume of the combustion fan 5 at the time of slow ignition combustion, and other configurations are the same. This is similar to the conventional example.

FIG. 1 shows the configuration of the air volume control provided in the control device 17 of the combustion apparatus of the present embodiment. In addition to the combustion control unit 30 and the fan control unit 31 being provided as in the conventional example, the present embodiment is also implemented. The example is provided with a characteristic slow ignition air flow rate stability determining unit 32 and a slow ignition operation amount limiting unit 33. The operations of the combustion control unit 30 and the fan control unit 31 are the same as those of the conventional example, and therefore their explanations are omitted. When the flow sensor 15 detects the water flow and the combustion fan 5 is driven to rotate at the rotation speed of the slow ignition air volume, the slow ignition air volume stability determining unit 32 receives the air volume detection signal from the air volume detection means 23, and (B), whether or not the value of the detected air volume falls within a range of a gentle ignition air volume ± aV given on the basis of the slow ignition level, that is, the value of the detected air volume is Q at the lower limit level of the slow ignition air volume range. Judge whether or not the point is broken. Then, after it is confirmed that the air volume has fallen into the gentle ignition air volume range, the air volume stable point at which the detected air volume value stabilizes is determined. In general, when the combustion fan 5 is started up to a slow ignition air volume, the actual air volume exceeds the slow ignition level and bulges upward in an overshoot shape, then converges to the slow ignition level and is stabilized.

The slow ignition air volume stability determining unit 32 determines the stable point S of the detected air volume. As a method for determining the air flow rate stable point, various configuration modes can be adopted. For example, the time from when the actual air flow reaches the Q point in the slow ignition air flow range to when it reaches the S, which is the air flow stable point, is obtained by experiments in advance, and that time elapses after the Q point is cut off by a timer or the like. Alternatively, it may be determined that the air volume stable point has been reached when the time elapses, or, as shown in FIG. 3, the detected air volume reaches the Q point at the lower limit level of the slow ignition air volume range. Reached t
Starting from the point of _0, the detected air volume is taken in by the air volume detection sensor of the air volume detection means 23 at minute time intervals such as 0.1 seconds at t ₁ , t ₂ , ... Although the air flow rate stable point may be settled when the difference from the previous intake data falls within a predetermined setting range, in this embodiment, as shown in FIG. 3, the detected air volume reaches the point t _0. After that, the detected air volume is taken in at a short time interval of, for example, 0.1 seconds, and when the captured data is in the slow ignition air volume range for N consecutive times, the last N The time point at which the detected air volume value is captured is determined as the air volume stable point S, and the air volume determination signal is added to the slow ignition operation amount limiting section 33.

When the slow ignition operation amount limiting unit 33 receives a confirmation signal of the air flow stable point from the slow ignition air flow stability determining unit 32, the operation amount of the combustion fan 5 at the time of receiving the confirmation signal. In the example, the fan applied voltage is used as a reference operation amount (reference operation voltage), and the upper and lower limiters are given as ± bV with reference to this reference operation voltage. The limiter ± bV is given in advance by experiments or the like as a stable flame range in which the point ignition flame does not extinguish, and as a possible range of the air flow rate control that can prevent deterioration of combustion performance.

As a method of giving this limiter, a range of ± bV is given to a memory or the like in advance, and when the reference operation amount is fixed, a limiter of ± bV is provided around the reference operation amount. Well, or the limiter range corresponding to the magnitude of the reference operation amount (reference applied voltage) is stored in advance by table data, etc., and when the reference operation voltage is confirmed, the determined operation amount (operation voltage) The limiter range corresponding to the size may be read out from the table data and given, and further, an arithmetic expression indicating the size of the limiter range corresponding to the size of the reference operation amount is given, and the reference operation is performed. When the amount is determined, the limiter may be calculated and given by substituting it in the arithmetic expression, and the limiter is given centering on the reference operation amount by an appropriate method. Then, the limiter information is added to the fan control unit 31.

The fan control unit 31 controls the slow ignition air flow rate of the combustion fan 5 within the limiter range provided by the slow ignition operation amount limiting unit 33.

In this embodiment, since the slow ignition air flow rate control is performed within the limiter range given by the slow ignition operation amount limiting section 33, for example, as shown in FIG. Even if the sensor output suddenly decreases at the portion a due to breathing or the like, when the fan control voltage is controlled in the increasing direction by the fan control unit 31 in an attempt to compensate for this sudden decrease, the portion b in FIG. As shown in FIG. 2A, there is no abnormal increase, and the upper limit level of the limiter, that is, the operation reference applied voltage W is +
The upper limit limiter is higher by bV, and the fan applied voltage is not increased beyond the upper limit limiter, so that it is possible to prevent a problem such as extinction of flame.

Further, the air volume control during the slow ignition period is not fixed as in the example of the publication shown in FIG. 5, but the air volume control can be freely performed within the limiter range. As shown in, the air volume detection means at the time of point ignition
The decrease in the actual air volume that is actually decreasing when the sensor output of 23 decreases can be compensated for by increasing the fan applied voltage within the limiter range, which improves the combustion performance of the burner 4 and increases the air volume. It is possible to prevent the flame from extinguishing due to a shortage, suppress the generation of CO gas and the like, and achieve cleaner combustion.

Further, since the operation reference voltage is determined on the basis of the air flow rate stable point at which the detected air flow rate is stable, the reference applied voltage of the slow ignition air flow rate is determined as an optimum value, and the control range of this optimum reference applied voltage is set. Since the limiter is provided, the reliability of the control of the slow ignition air volume is enhanced, and along with this, the accuracy of the control of the slow ignition air volume is also enhanced.

Further, in the present embodiment, in a situation in which the pre-purge is not necessary, it is possible to move to the point ignition operation immediately after the combustion fan 5 is rotated and the air flow stable point is established. As always, the prepurge period T ₁
Since it is not necessary to wait for the ignition to proceed to the ignition, the effect of enabling the ignition operation to be performed quickly after the fan has rotated.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the above embodiment, the limiter in the slow ignition operation amount range is given by ± bV with respect to the reference operation voltage, but the lower limiter is omitted and only the upper limiter + bV with respect to the reference operation voltage is given. May be.

In the above embodiment, the hot water supply device is used as the combustion device. However, the combustion device of the present invention is of a burner combustion type such as a bath kettle, a heater, a cooler, a heating / cooling machine, and an air conditioner. It is applied to various combustion devices.

Further, in the above-mentioned embodiment, the combustion fan 5 is of the pushing type, but of course, it may be of the suction type.

Further, the burner 4 may be a burner having no combustion capacity switching function or may be a combustion capacity switching type burner. Burner 4 of combustion capacity switching type (combustion surface is one-sided combustion, two-sided combustion,
When the combustion capacity is switched by switching the number of combustion surfaces, such as three-sided combustion), the gas supply amount varies depending on the switching combustion capacity. A range is given, and every time the combustion capacity is switched by the slow ignition operation amount limiting unit 33, a different limiter according to the switched combustion capacity is provided as in the case of the above embodiment.

Further, in the above embodiment, the operation amount of the combustion fan 5 is the fan applied voltage, but the drive current and the work amount of the combustion fan 5 are the operation amounts, and the combustion fan 5 is controlled by these fan drive current and work amount. The air flow rate may be controlled. Also in this case, similarly to the present embodiment, the reference operation amount is determined when the air flow stable point is determined, and the limiter for the slow ignition air flow control is given to the reference operation amount of the fan drive current and the work amount. Become.

[0034]

According to the present invention, since the limiter for limiting the range of the slow ignition operation amount of the combustion fan is given on the basis of the reference operation amount of the combustion fan, a breathing phenomenon occurs due to combustion expansion during point ignition. , Even if the airflow detection value of the airflow detection means suddenly decreases due to this breathing, the operation amount of the combustion fan does not abnormally increase beyond the limiter to compensate for this sudden decrease. It is possible to reliably prevent the flame from extinguishing due to the abnormal increase in the air volume caused by the abnormal increase in the fan drive operation amount.

Further, although the actual air volume decreases due to the breathing during point ignition, in the present invention, since the operation amount of the combustion fan can be freely controlled within the range of the limiter, the actual air volume decreases due to the breathing. The amount of air is controlled in a direction that compensates for the minute amount, which effectively controls the slow ignition air flow rate commensurate with the combustion amount, prevents deterioration of combustion performance, eliminates the occurrence of flame extinction due to insufficient air flow, and produces less CO gas. Slow ignition combustion can be achieved.

Further, since the reference manipulated variable of the combustion fan that gives the limiter is given by the slow ignition air amount stability determining unit on the basis of the time when the stability of the slow ignition air amount is determined, it is given as the optimum reference amount of the slow ignition air amount. That means
Since the limiter is given on the basis of the reference operation amount of the optimum slow ignition air flow rate, the control range of the slow ignition air flow rate becomes appropriate and the reliable slow ignition air flow rate control becomes possible.

Further, according to the present invention, in a situation where pre-purge is not necessary, after the slow ignition air volume stability determining unit determines that the slow ignition air volume is stable, the burner can be immediately ignited. Since it is not necessary to always wait for ignition until the pre-purge period elapses as in the conventional example of the publication, it is possible to achieve an excellent effect that the ignition operation of rotating the combustion fan can be performed in a short time. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a combustion apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an operation of the apparatus of the embodiment.

FIG. 3 is an explanatory diagram of an operation of determining an air volume stable point at the time of rising of a slowly ignited air volume.

FIG. 4 is an explanatory diagram showing a situation in which a sensor output of an air volume detection unit is reduced due to breathing at the time of ignition at a slow ignition point and an actual air volume is reduced.

FIG. 5 is an explanatory diagram showing a relationship between a slowly ignited air volume and a fan drive voltage according to the conventional example disclosed in the publication.

FIG. 6 is a schematic configuration explanatory view of a general water heater as a combustion device.

FIG. 7 is a block diagram of combustion control and fan control of a conventional water heater.

FIG. 8 is an explanatory diagram of various combustion control data of the combustion device.

FIG. 9 is an explanatory diagram showing an operating situation of a conventional water heater.

[Explanation of symbols]

5 combustion fan 23 Air volume detection means 30 Combustion control unit 31 Fan controller 32 Slow ignition air flow stability determination unit 33 Slow ignition operation amount limiter

Continued front page    (72) Inventor Seiichi Mori               3-4 Fukamidai, Yamato City, Kanagawa Prefecture Stock               Inside the company Gaster                (56) References JP-A-2-161212 (JP, A)                 JP-A-2-161210 (JP, A)                 JP-A-4-316912 (JP, A)

Claims (2)

(57) [Claims] 1. An air volume detecting means for detecting an actual air volume of combustion air supplied to a burner by a supply / exhaust combustion fan, and a combustion air volume suitable for a combustion amount based on an air volume detection value of the air volume detecting means. In a combustion device including a fan control unit that controls the operation amount of the combustion fan so that
During the slow ignition combustion at the time of point ignition of the burner, the slow ignition air volume stability determination unit that determines the air volume stable point at which the air volume is stable after the air volume detection value of the air volume detection means falls within a predetermined slow ignition air volume range, A limiter for limiting the slow ignition operation amount range of the fan control unit on the basis of the operation amount of the combustion fan at the time when the stable point of the air amount is determined by the slow ignition air amount stability determining unit, and using the reference operation amount as a reference. And a slow ignition operation amount limiting section for providing the combustion apparatus. 2. The burner is composed of a burner of a capacity switching type that switches a combustion capacity by switching a combustion surface, and the slow ignition manipulated variable limiting unit,
The combustion apparatus according to claim 1, wherein different limiters are provided according to the switched combustion capabilities.