JP2550373B2 - Control device for forced air combustion system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used in a water heater, a heater, etc., and uses two or two burners (hereinafter simply referred to as “two”) burners to perform combustion. The present invention relates to a forced air combustor in which supply of supply air is performed by a blower, and particularly to a compulsory device that switches the number of burners to be used according to the required combustion amount.

[Conventional technology]

In the forced air blowing type combustion device used for a water heater, etc., a combustion device with two burners is used to secure a large amount of heat generation. In the case of a large amount of heat generation, two burners are used. In the case of small calorific value, one burner or a series of burners (hereinafter simply referred to as "one") is used, and it is calculated according to the temperature volume for setting the hot water supply water temperature, the incoming water temperature, and the incoming water amount. Combustion is performed by switching the number of burners to be used according to the required amount of heat generation. Further, in order to easily control the combustion amount, a combustion amount range overlapping the combustion amount range of the single burner and the combustion amount range of the two burners is provided. Then, when the set combustion amount is increased during the combustion with the single burner, the combustion amount is gradually increased with the single burner, and when the increased set combustion amount exceeds the combustion capacity of the single burner, the double burner is used. Is switched to.

Switching to this dual burner simply opens the solenoid valve provided in the fuel supply path, so if the dual burner is used as it is with the maximum combustion amount of the single burner, the fuel will increase rapidly. And very dangerous. Further, in order to make the change of the combustion amount continuous when correcting the combustion amount based on the tapping temperature, after reaching the maximum combustion amount in one burner, the combustion amount is once reduced to 2 at the time of ignition, Switching to this burner is performed.

[Problems to be solved by the invention]

However, if there is a demand for a large increase in the combustion amount due to a change in the set water temperature, etc. during combustion with only one burner, switching to the two burners after the maximum combustion amount of the single burner has passed. Since the combustion amount that has been once increased is switched again after being reduced, there is a problem that it takes time until the combustion state stabilizes and rapid change cannot be performed.

The present invention is a forced air combustor that uses two burners. When the required combustion amount increases during use of one burner and it is switched to two burners, the forced combustion amount can be quickly switched to the required combustion amount. The purpose is to provide a device.

[Means for solving problems]

The present invention includes a blower for adjusting the supply amount of combustion air, a proportional valve that is forced according to the operation of the blower is provided in the fuel supply passage, and the fuel supply passage downstream of the proportional valve is provided. While branching and providing a first burner and a second burner downstream of each branch pipe, respectively, an electromagnetic valve is provided in the branch pipe to the first burner, and the electromagnetic valve is opened so that the first burner and The first combustion that causes the second burner to burn together and the second combustion that causes the electromagnetic valve to close to burn only the second burner have combustion amount ranges that overlap with each other. A controller for a forced air combustion device that selects either the first combustion or the second combustion according to a set combustion amount to be set and controls the selected combustion, according to the set combustion amount during ignition. Before When the first combustion or the second combustion is selected, the blower and the proportional valve are controlled to be slowly ignited, and when the set combustion amount is changed during the combustion, the first combustion or the second combustion is selected according to the changed set combustion amount. When the first combustion or the second combustion is selected and the opening / closing control of the solenoid valve is performed in accordance with the selection, when switching from the second combustion to the first combustion, the energization current of the proportional valve in the second combustion is changed. Immediately without causing the maximum current, the blower and the proportional valve to control the slow ignition to open the solenoid valve, then,
The blower and the proportional valve are controlled according to the changed set combustion amount, and at the time of switching from the first combustion to the second combustion, the electromagnetic valve is closed and the set combustion amount changed. The technical means is to control the blower and the proportional valve in accordance with the above.

[Action]

According to the present invention, at the time of ignition, the first combustion or the second combustion is selected according to the combustion amount set by the combustion amount setting means, the blower and the proportional valve are controlled to be slowly ignited in the selected combustion state, and after ignition, The blower and the proportional valve are controlled according to the set combustion amount.

Further, when the set combustion amount is changed during combustion, the first combustion or the second combustion is selected according to the changed set combustion amount. When controlling the opening and closing of the solenoid valve according to this selection, the second
When switching from combustion to the first combustion, the blower and the proportional valve were immediately controlled by slow ignition without opening the energization current of the proportional valve to the maximum current in the second combustion, and the solenoid valve was opened. The blower and proportional valve are controlled according to the set combustion amount. Therefore, since the operation of opening the solenoid valve to the first combustion is not performed after the ignition control is controlled again to the maximum combustion amount in the second combustion, the fire transfer occurs at a large combustion amount. In this way, it is possible to perform a safe fire transfer, reduce the switching time, and quickly obtain the changed set combustion amount.

Further, when switching from the first combustion to the second combustion, the solenoid valve is closed and the blower and the proportional valve are controlled according to the changed set combustion amount, so that the changed set combustion amount is promptly changed. can get.

〔The invention's effect〕

In the present invention, when the set combustion amount is changed during combustion, the first and second combustions are selected according to the changed set combustion amount, and the solenoid valve is opened / closed according to the selection result. After that, the blower and the proportional valve are controlled according to each set combustion amount. In particular, when switching from the second combustion to the first combustion, the solenoid valve is opened immediately under the control of the slow ignition current, so that a safe fire transfer can be performed and the setting can be performed quickly. The amount of combustion can be changed.

〔Example〕

Next, a control device of the forced air blowing type combustion device of the present invention will be described based on an embodiment shown in the drawings.

The gas combustion type water heater 1 shown in FIG. 2 uses a gas such as propane gas as a fuel, and is provided with a combustor case 10, inside which a fuel gas supplied by a gas supply pipe 20 is supplied. A dual burner 11 for burning is provided. The dual burner 11 is the first burner as shown in FIG.
11a and a second burner 11b, and switches between two combustion states, a first combustion in which both the first burner 11a and the second burner 11b perform combustion, and a second combustion in which only the second burner 11b performs combustion. be able to. The first combustion and the second combustion are combustion states set in order to easily realize the large combustion amount and the small combustion amount, respectively, as shown by the solid line A and the broken line B in FIG. In the present embodiment, when the set combustion amount is changed in each combustion state, the range of the small combustion amount by the second combustion is set so that the combustion state does not have to be changed when the change amount is small. From Q ₁ to Q ₃ , the large combustion amount range from the first combustion is set from Q ₂ to Q ₄ , respectively, so that overlapping combustion amounts can be obtained from Q ₂ to Q ₃ . Combustion air is supplied to the dual burner 11 by a combustion fan 12 provided in the combustor case 10 as the blower of the present invention.

A heat exchanger 13 connected to a water supply pipe (not shown) is provided above the inside of the combustor case 10, and the water passing through the inside is 2
It is heated by the heat generated by the combustion of the continuous burner 11. In the vicinity of the dual burner 11 in the combustor case 10, a sparker 14 as an ignition device and a frame rod 15 as a flame detecting means are provided.

In the gas supply pipe 20 as a fuel supply path, a source solenoid valve 21, a main solenoid valve 22, which allows the fuel gas to pass when energized from the upstream side,
A governor proportional valve 23 for adjusting the supply amount of the fuel gas by controlling the supply pressure is provided, and a downstream nozzle of the governor proportional valve 23 for ejecting fuel to the dual burner 11 is provided.

The double nozzle 16 includes a first nozzle 16a and a second nozzle 16b.
Consisting of a first burner 11a and a second burner 11b, respectively.
Eject fuel to. Further, in the present embodiment, in order to change the supply amount of the fuel gas stepwise according to the usage state of the feeder, the switching solenoid valve as the solenoid valve of the present invention is provided in the gas supply pipe 20 to the first nozzle 16a. 24 is provided, and the switching solenoid valve 24 is energized to be in the open state during the first combustion, and is not energized to be in the closed state during the second combustion.

The combustion exhaust gas after combustion is exhausted to the outside from the exhaust port 2, but in the second combustion, the combustion exhaust gas is mixed with the combustion air supplied to the first burner 11a and exhausted, so that drainage may occur. Few.

An outlet hot water temperature thermistor 25 that detects the temperature of the heated water is provided downstream of the heat exchanger 13.

As shown in FIG. 4, the control device 30 is composed of a microcomputer 40 (hereinafter referred to as the CPU 40) as the center and the following circuits.

The sparker circuit 31 is a circuit for energizing a high voltage generation circuit for generating spark discharge in the discharge gap of the sparker 14 via a relay.

The fan circuit 32 drives the combustion fan 12 under the control of the CPU 40, and includes a rotation speed detection circuit for detecting the rotation speed of the combustion fan 12.

The proportional valve circuit 33 is a circuit for energizing the governor proportional valve 23 in order to adjust the amount of fuel gas supplied to the dual burner 11, and the energizing current therefor detects the rotation speed of the fan circuit 32. It is determined according to the rotation speed of the combustion fan 12 detected by the circuit. In this embodiment, this proportional valve circuit
From 33, the slow ignition current Ia, which has nothing to do with the set combustion amount at the time of ignition, is applied to the governor proportional valve 23.

The water amount detection circuit 34 detects the inflowing water amount by detecting the rotational speed of the impeller of a water amount sensor provided in a water supply pipe (not shown) upstream of the heat exchanger 13.

The water valve circuit 35 is a circuit for driving a gad motor of a water amount control valve (not shown) provided in the water supply pipe upstream of the water amount sensor, and the water amount control valve is provided with a potentiometer for detecting its opening. However, the water amount control valve is controlled to an opening degree according to the control state based on the detection signal from the potentiometer.

The water temperature detection circuit 36 detects the temperature of the water heated by the heat exchanger 13 from the signal from the hot water temperature thermistor 25 and the signal from an incoming water temperature thermistor (not shown) provided upstream of the heat exchanger 13. A circuit for detecting and including the temperature of water flowing into the heat exchanger 13.

The control circuit 37 is an operation unit for operating the operating state of the gas combustion type water heater 1, and includes an operation switch and a temperature setting switch. This control circuit 37
Are connected by wire-saving two-wire wiring (not shown) so that they can be operated remotely, and are operated by electric power supplied from the two-wire wiring. Then, the operation signal and the temperature setting signal are digitally generated, modulated into a predetermined carrier wave, and transmitted.

The interface circuit 38 is based on the above circuits and the original solenoid valve.
21, main solenoid valve 22, switching solenoid valve 24 and frame rod
This is a circuit for transmitting signals between the CPU 15 and the CPU 40, which will be described later. Especially, when the flame of the dual burner 11 is no longer detected in the energizing circuit to the source solenoid valve 21 and the main solenoid valve 22. Is equipped with a safety circuit 39 for stopping the fuel.

The CPU 40 comprehensively controls the operating states of the above circuits, includes a ROM 41 and a RAM 42 as storage devices, analyzes the operation signal from the control circuit 37 from the carrier wave, and responds to the setting state such as the set temperature. Then, the gas combustion type water heater 1 is operated in the order of operation stored in the ROM 41 in advance.

 Further, the CPU 40 has the following functions, respectively.

As the combustion amount setting function 43, a setting state such as a set temperature by the control circuit 37, a required combustion amount is calculated based on each signal from the water amount detection circuit 34 and the water temperature detection circuit 36,
Set the combustion amount of dual burner 11.

The combustion state selection function 44 includes the first combustion or the second combustion based on the combustion amount set by the combustion amount setting function 43.
Combustion is selected.
When the set combustion amount is changed by the set temperature, supply amount, and incoming water temperature of the control circuit 37 during the second combustion when the 24 is closed, can the set combustion amount be obtained while continuing the second combustion? , Or preselect if the first combustion should be changed. As a result, when the first combustion is selected, it is possible to immediately change the current supplied to the governor proportional valve 23 to the slow ignition current Ia without making it the maximum current in the second combustion. Therefore, when this selection is not made, the energizing current to the governor proportional valve 23 is set to the maximum current value with the increase of the set combustion amount, and then is set to the slow ignition current Ia. Then, the current for slow ignition Ia
Therefore, the combustion amount is changed promptly.

As the blower control function 45, the combustion fan 12 is controlled based on the combustion amount set by the combustion amount setting function 43 and the combustion state selected by the combustion state selection function 44,
Combustion air is supplied to the burner 11. Then, particularly when the second combustion is shifted to the first combustion, the rotation speed of the combustion fan 12 is once changed to the slow ignition rotation speed, and then the switching electromagnetic valve 24 is energized to be in an open state. The rotation speed is controlled according to the set combustion amount.

As the fuel supply amount control function 46, the energizing current of the governor proportional valve 23 and the switching solenoid valve are selected according to the selected combustion state.
The energization state of 24 is controlled, the governor proportional valve 23 is controlled according to the detected rotation speed of the combustion fan 12, and the fuel supply amount to the burner 11 is controlled. When the second combustion is transitioned to the first combustion, the switching solenoid valve 24 is changed after the current to the governor proportional valve 23 is once changed to the slow ignition current Ia as in the case of the combustion fan 12. Energize to open the state, and then apply a current corresponding to the set combustion amount to the governor proportional valve 23. This is because in the transition from the first combustion to the second combustion, the combustion amount can be surely reduced by simply closing the switching solenoid valve 24, while the second combustion to the first combustion. In the case of transition, the first burner 11a is newly ignited at the time of switching, and ignition cannot be safely performed unless proper control is performed. Therefore, fuel gas is supplied in the same state as at the time of ignition. Supply.

Next, the operation of the gas combustion type water heater 1 of the present embodiment having the above configuration will be described with reference to FIG.

When the user turns on the operation switch, the control device 30 is activated by the signal, and the operation is started in a predetermined sequence.

The control device 30 calculates the combustion amount based on the set temperature, water temperature, and water amount, and sets the combustion amount. Depending on the set combustion amount, the combustion fan 12 and governor proportional valve 23
And the switching solenoid valve 24 is controlled, and the adjusted combustion gas is ejected from the first nozzle 16a and the second nozzle 16b to the first burner 11a and the second burner 11b, respectively. At this time, the combustion air to the burners 11a and 11b is sent to the combustion fan 12
Supplied by

When the set temperature is changed and the set combustion amount is changed, the current of the governor proportional valve 23 is changed according to the changed amount in each combustion state. When the set combustion amount cannot be obtained in each combustion state, the switching solenoid valve 24 is changed to change the combustion state.

Now, for example, as shown in FIG. 3, when the current value of the governor proportional valve 23 is Im smaller than the slow ignition current Ia in the second combustion in which the switching solenoid valve 24 is closed, the combustion amount is Is Qm
Is. At this time, the set combustion amount is drastically changed,
Assuming that the changed combustion amount is Qn, in the second combustion shown by the broken line B, the combustion amount Qn cannot be obtained even if the energizing current to the governor proportional valve 23 is increased. Therefore, CPU40
The first combustion is selected by. Then, the energization current to the governor proportional valve 23 is increased to the slow ignition current Ia, and then the switching solenoid valve 24 is energized to be in the open state and changed to the first combustion. After that, the current of the governor proportional valve 23 is increased to In so that the combustion amount becomes Qn.

Further, when the energization current of the governor proportional valve 23 in the second combustion is Ip larger than the slow ignition current Ia and the combustion amount is Qp, if the set combustion amount is changed to Qn as in the above case, As in the case of, the combustion amount Qn cannot be obtained in the second combustion, so the first combustion is selected and the governor proportional valve is selected.
The conduction current of 23 is reduced to the slow ignition current Ia. After that, in the same way, the combustion is changed to the first combustion and the current is changed to In.
Qn is obtained.

Here, the combustion amount when the governor proportional valve 23 is controlled to the slow ignition current Ia is, as shown in FIG. 3, both when the switching solenoid valve 24 is in the open state and when it is in the closed state. 1
Combustion amount Q ₂ as an overlapping combustion amount range of combustion and second combustion
Since it falls within the range of Q ₃ , a stable combustion state can be obtained especially at the time of transition from the second combustion to the first combustion.

Thus, when the second combustion is changed to the first combustion, the energizing current of the governor proportional valve 23 is changed to the slow ignition current Ia immediately after the first combustion is selected, so that the switching solenoid valve is used. 24 is energized quickly and can be opened quickly. Therefore, the amount of combustion can be changed safely and promptly.

[Brief description of drawings]

FIG. 1 is a functional block diagram for explaining the operation of the gas combustion type water heater of this embodiment, FIG. 2 is a schematic configuration diagram showing the gas combustion type water heater of this embodiment, and FIG. 3 is of this embodiment. FIG. 4 is a block diagram showing the configuration of the control device of the present embodiment, which is a characteristic diagram showing a change in the combustion amount with a change in the current value of the governor proportional valve. In the figure, 11a ... first burner, 11b ... second burner, 12 ...
Combustion fan (blower), 23 ... Governor proportional valve (proportional valve), 24 ... Switching solenoid valve (solenoid valve), 30 ... Control device, 40 ... Microcomputer (combustion amount setting means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliography SHO 62-63554 (JP, U) ACT SHO 56-28569 (JP, U) ACT SHO 56-107147 (JP, U)

Claims (1)

(57) [Claims] 1. A blower for adjusting the supply amount of combustion air, a proportional valve controlled according to the operation of the blower is provided in a fuel supply passage, and the fuel supply passage downstream of the proportional valve. And a first burner and a second burner are provided downstream of each branch pipe, and an electromagnetic valve is provided in the branch pipe to the first burner to open the electromagnetic valve to open the first burner. And first combustion in which the second burner is combusted together and second combustion in which only the second burner is combusted by closing the electromagnetic valve, have combustion amount ranges overlapping with each other, and combustion amount setting means In the controller of the forced air combustion device, which selects either the first combustion or the second combustion according to the set combustion amount set by, and controls the selected combustion, when the ignition is performed, the set combustion amount is set to the set combustion amount. Depending on When the first combustion or the second combustion is selected, the blower and the proportional valve are controlled to be slowly ignited, and when the set combustion amount is changed during combustion, the set combustion amount is changed according to the changed set combustion amount. When the first combustion or the second combustion is selected and the opening / closing control of the solenoid valve is performed according to the selection, when switching from the second combustion to the first combustion, the energizing current of the proportional valve is changed to the second current. Immediately without making the maximum current in combustion, the blower and the proportional valve are controlled by the slow ignition to open the solenoid valve, and then the blower and the proportional valve are controlled according to the changed set combustion amount. However, at the time of switching from the first combustion to the second combustion, the solenoid valve is closed and the blower and the proportional valve are controlled according to the changed set combustion amount. Control device for forced draft combustion device.