JPH01167524A - Control device for forced air blowing type combustion device - Google Patents

Abstract

PURPOSE:To enable the number of burners to be easily changed by a method wherein an energized current for a fuel supplying proportional valve is determined under a predetermined relation in response to the number of rotation of a blower by a control device without having any relation with an opened or closed state of fuel changing-over solenoid valve. CONSTITUTION:Combustion air is supplied to a first burner 11a and a second burner 11b by a blower 12. An energization current of a governor proportional valve 23 for adjusting an amount of supplying fuel is determined under a predetermined relation by a control device 30 in response to the number of rotation of the blower 12. When a combustion amount is much in its volume, a changing- over solenoid valve 24 is opened and fuel is supplied from the first burner 11a and the second burner 11b through a first nozzle 16a and a second nozzle 16b. In turn, when the combustion amount is less in its volume, the solenoid valve 24 is closed. In this way, the combustion through the two burners and the combustion through one burner can be easily changed over with each other.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used for water heaters, space heaters, etc.
Regarding forced air combustion equipment that uses two burners (hereinafter simply referred to as "two burners") and supplies combustion air with a blower, combustion is performed by switching the number of burners used depending on the required combustion area. Pertaining to things.

[Prior art] In water heaters, etc., a combustion device equipped with two burners is used to ensure a large amount of heat, and the number of burners used is switched depending on the required amount of heat. In this case, two burners are used, and in the case of a small calorific value, one burner or one burner (hereinafter simply referred to as "one burner") is used.

[Problems to be Solved by the Invention] However, in combustion equipment in which combustion air is supplied by a blower, normal combustion cannot occur unless the mixture ratio with the fuel is adjusted appropriately. In such combustion equipment, when switching the number of burners used, appropriate control is required between the proportional valve that supplies fuel and the blower source that supplies combustion air. Furthermore, if the amount of combustion is reduced in order to reduce the required calorific value, the combustion temperature will be lowered, making it easier for water vapor in the combustion gas to generate drainage. Therefore, there are problems in that the minimum combustion amount must be limited to a combustion amount that does not generate 1-lene, and the amount of water supplied in water heaters and the like must be limited.

SUMMARY OF THE INVENTION An object of the present invention is to provide a forced air combustion device that can easily switch between combustion using two burners and combustion using one burner, and is less likely to generate drain even during small combustion.

[Means for Solving the Problems] The present invention includes a blower for supplying combustion air, and a first air blower that is supplied with fuel regulated by a proportional valve provided in a fuel supply path via a solenoid valve. In the control device for a forced air combustion device, the control device includes a burner and a second burner to which the fuel is directly supplied, and opens and closes the solenoid valve based on the combustion amount set by the combustion amount setting means. The technical means is to determine the energizing current of the proportional valve in a predetermined relationship based on the rotation speed of the feeder, regardless of the open/closed state of the electromagnetic valve.

Effect] In the present invention, combustion air is supplied to the first burner and the second burner by a blower, and the current flowing through the proportional valve is determined in a predetermined relationship based on the rotation speed of the blower. Further, the solenoid valve is in an open state when the combustion amount set by the combustion amount setting means is large, and fuel is supplied to the first burner and the second burner, and is in a closed state when the combustion amount set is small. Fuel is supplied only to The energizing current of the proportional valve is determined based on the rotation speed of the blower, regardless of the opening/closing of the solenoid valve, so the proportional valve supplies fuel to the first burner and It can be fed to a second burner.

[Effects of the Invention] In the present invention, the energizing current of the proportional valve is determined in a predetermined relationship with the rotation speed of the blower, regardless of the opening/closing of the solenoid valve. is always supplied in a predetermined relationship with the combustion air. Therefore, it is possible to easily change between combustion using two burners and combustion using one burner. Furthermore, since combustion air is supplied to the second burner even when the solenoid valve is closed, as when it is open, the combustion gas that is combusted only by the first burner is transferred to the second burner. The combustion gas is mixed with the combustion air supplied to the combustion gas, and the water vapor pressure in the combustion gas decreases, making it difficult for drainage to occur.

[Example] Next, a forced air combustion apparatus of the present invention will be described based on an example shown in the drawings.

The gas combustion type water heater 1 shown in FIG. 2 uses gas such as propane gas as fuel, and a combustor case 10 is provided inside the water heater case (not shown), and a fuel supply channel is provided inside the combustor case 10. As shown in FIG. It consists of two burners 11b. Further, the combustor gate 10 is equipped with a combustion fan 12 using a three-phase Y-connected brushless DC motor as the blower of the present invention, and supplies combustion air to the two-bar burner 11 .

A heat exchanger 13 connected to a water supply pipe (not shown) is provided above the combustor case 10, and water passing through the interior is heated by a dual burner 11. Further, a sparker 14 as an ignition device and a flame rod 15 as a flame detection means are provided near the dual burner 11 in the combustor case 10.

The gas supply pipe 20 is provided with a source solenoid valve 21 and a main solenoid valve 22 that allow fuel gas to pass through when energized from the upstream side, and a governor proportional valve 23 that adjusts the supply amount of fuel gas by controlling the supply pressure. At the downstream end there is a dual burner 1
In order to inject fuel to the burner 1, a double nozzle 16 consisting of a first nozzle 16a and a second nozzle 16b provided corresponding to the first burner 11a and the second burner 11b, respectively, is provided.

゛In addition, in this embodiment, in order to change the supply amount of fuel gas in stages according to the usage status of the water heater, a gas supply pipe 20 is connected to the first nozzle 16a, which is one of the two nozzles 16.
A switching solenoid valve 24 is provided.

Furthermore, when the switching electromagnetic valve 24 is in the closed state, the governor proportional valve 23 adjusts the supply pressure of each nozzle t\ downstream thereof in accordance with the applied current, similarly to when the switching solenoid valve 24 is in the open state.

The combustion exhaust gas after combustion is exhausted to the outside from the exhaust port 2, but when only the second burner 11b is burning, the combustion exhaust gas is
It is mixed with the combustion air supplied to the first burner 11a and exhausted. At this time, the combustion air supplied to the first burner 11a is not used for combustion of fuel gas, and therefore does not contain water vapor associated with combustion. The water vapor pressure in the combustion exhaust gas is lowered by being mixed with the combustion air supplied to the first burner 11a, making it difficult to condense.

In particular, during combustion when the amount of combustion is small, drainage is generally likely to occur because the calorific value is small, but in this example, such drainage is mixed with the air supplied to the first burner Ila. Rarely occurs.

Note that on the downstream side of the heat exchanger 13, an outlet hot water temperature thermistor 25 is provided to detect the temperature of the heated water.

The control bag T30 is the control device of the present invention, and as shown in FIG. 3, it is composed of the following circuits centered on a microcomputer 40 (hereinafter referred to as CPU 40).

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

The fan circuit 32 is a brushless DC of the combustion fan 12.
The motor is controlled by the CPtJ40 and driven according to the required combustion amount. Furthermore, in this embodiment, since the current supplied to the governor proportional valve 23 is determined based on the rotation speed of the combustion fan 12, this fan circuit 3
2 is equipped with a rotation speed detection circuit for detecting the rotation speed of a brushless DC motor that drives 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. Regardless of the control state of the electromagnetic valve 24, the desired air-fuel ratio is determined based only on the rotation speed of the brushless DC motor detected by the rotation speed detection circuit of the fan circuit 32.

The water amount detection circuit 34 detects the amount of water flowing in by detecting the rotation speed of an 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 geared motor of a water flow control valve (not shown) provided in a water supply pipe upstream of the water flow sensor, and the water flow control valve is equipped with a potentiometer for detecting its opening degree. The water flow control valve is controlled to an opening degree according to the control state based on a detection signal from a potentiometer.

The water temperature detection circuit 36 detects the temperature of the heated water in the heat exchanger 13 based on the signal from the above-mentioned outlet water temperature thermistor 25 and the signal from the inlet water temperature thermistor (not shown) provided in the water supply pipe upstream of the heat exchanger 13. This is a circuit for detecting the temperature of water and the temperature of water flowing into the heat exchanger 13, respectively.

The control circuit 37 is an operation section for controlling the operating state of the gas combustion 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) to enable remote cattle operation, and are operated by power supplied from this two-wire wiring.

Then, an operating signal and a temperature setting signal are digitally generated, modulated onto a predetermined carrier wave, and sent out.

The interface circuit 38 is a circuit for transmitting signals between the above-mentioned circuits, the original solenoid valve 21, the main solenoid valve 22, the switching solenoid valve 24, and the frame rod 15, and the CPtJ40 described later. The energizing circuit for the valve 21 and the main solenoid valve 22 includes a safety circuit 3 for stopping the fuel when the flame of the dual burner 11 is no longer detected.
9 is provided.

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

Further, the CPU 40 is the combustion amount setting means of the present invention, and calculates the required combustion amount based on the setting state such as the temperature set by the control circuit 37 and each signal from the water amount detection circuit 34 and the water temperature detection circuit 36, and The combustion amount of the type burner 11 is set. In addition, the energization state of the combustion fan 12 and the switching solenoid valve 24 is controlled based on the set combustion amount,
Governor proportional valve 23 based on the rotation speed of combustion fan 12
is controlled, it is possible to supply fuel gas according to the set combustion amount.

In this embodiment, the first burner 11 is
Since combustion air is supplied to the first burner 11a and the second burner 11b, the combustion fan 12 can supply combustion air to the first burner 11a in the same way whether the switching solenoid valve 24 is in the closed or open state. The governor proportional valve 23 is adjusted based only on the rotational speed of the combustion fan 12 to supply fuel gas to a desired air-fuel ratio. Therefore, the combustion amount can be easily adjusted by switching the switching solenoid valve 24 according to the set combustion amount.

In this embodiment, as shown in FIG. 4, the combustion amount obtained in the dual burner 11 varies from the combustion amount Q, as shown by the broken line A, to the combustion amount Q, when only the second burner 11b is used. , when both the first burner 11a and the second burner 11b are used, the combustion amount Q2 is as shown by the solid line B.
to the combustion amount Q4.

Next, the gas combustion water heater 1 of this embodiment having the above configuration
The operation will be explained based on the first (2I).

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

The control device 30 controls the combustion fan 12 and the switching solenoid valve 24 according to the set combustion amount. Further, the governor proportional valve 23 is energized with a current value determined based on the rotation speed of the combustion fan 12. Then, each burner 11a
, 11b, combustion air is supplied to the combustion fan 12, and fuel gas corresponding to the current flowing through the governor proportional valve 23 is supplied from the first nozzle 16a and the second nozzle 16b. At this time, the supply amount adjusted by the governor proportional valve 23 is an amount controlled according to the rotation speed of the combustion fan 12, and is not related to the open state and open state of the switching solenoid valve 24.

Now, for example, as shown in FIG. 4, when the switching solenoid valve 24 is in the open state, the rotation speed of the combustion fan 12 is Nm, and the combustion amount is Qm.
Assuming that, the current flowing to the governor proportional valve 23 is Ia
It is. At this time, the set combustion amount is suddenly changed to a smaller value,
Assuming that the changed combustion amount is Qn, in order to maintain the switching solenoid valve 24 in the open state, the combustion fan 12 must be set to the rotation speed Nn, and accordingly, the governor proportional valve 23 The energizing current is changed to the current value Ib.

However, when the switching solenoid valve 24 is closed, the rotational speed of the combustion fan 12 remains at Nm, so the current flowing through the governor proportional valve 23 is the same current value Ia. Therefore, since the combustion amount Qn can be easily obtained, there is no need to change the rotational speed of the combustion fan 12 to change the current flowing to the governor proportional valve 23.

At this time, the combustion amount to be changed is simply determined by the switching solenoid valve 24.
Although this is rarely achieved easily by closing or opening the switching solenoid valve 24, it is possible to get closer to the desired combustion level by closing or opening the switching solenoid valve 24. Since the change in the rotation speed of the fan 12 can be reduced, the corresponding change in the current value of the governor proportional valve 23 is also reduced, improving responsiveness and quickly approaching the changed combustion amount. Can be done. The switching of the switching solenoid valve 24 and the change of the rotation speed of the combustion fan 12 due to this change in combustion amount are performed according to the combustion amount at that time and the combustion amount to be changed.
By determining in advance whether to switch the switching solenoid valve 24 or change the current value of the governor proportional valve 23, it is possible to change the combustion amount most suitable according to the characteristics of each combustion device. .

The fuel gas supplied to each burner is properly mixed with the combustion air supplied by the combustion fan 12 and combusted, regardless of whether the switching solenoid valve 24 is in the open or closed state. It can be the amount of combustion.

As a result, in this embodiment, the combustion amount of the two-bar burner 11 changes according to the change in the rotation speed of the combustion fan 12, and the combustion amount can be changed by switching the switching solenoid valve 24 as necessary. It can be changed quickly.

Furthermore, when the switching solenoid valve 24 is in the closed state and the amount of combustion is small, the temperature inside the combustor case 10 is low, so water vapor accompanying combustion tends to condense.
The combustion exhaust gas accompanying the combustion of only b is mixed with the combustion air supplied to the first burner Ila, and the water vapor pressure is reduced, so that less drain is generated in the combustor case 10.

As described above, in the present invention, in a combustion device that uses two or two burners and closes one of them depending on the usage condition, the set combustion amount can be quickly adjusted by simply switching the switching solenoid valve. Even when the amount of combustion is small, there is little drain generation.

[Brief explanation of the drawing]

Figure 1 is a block diagram for explaining the operation of this embodiment, and Figure 2 is a block diagram for explaining the operation of this embodiment.
The figure is a schematic configuration diagram showing the gas combustion type water heater of this embodiment, Figure 3 is a block diagram showing the control device of this embodiment, and Figure 4 shows the combustion amount, the rotation speed of the combustion fan, and the proportional valve. FIG. In the figure, 11a... first burner, 11b... second burner, 12... combustion fan (blower), 23... governor proportional valve (proportional valve), 24... solenoid valve for switching (electromagnetic valve), 30...control device, 40...microcomputer (combustion amount setting means).

Claims (1)

[Scope of Claims] 1) A first burner equipped with a blower for supplying combustion air and supplied with fuel regulated by a proportional valve provided in a fuel supply path via a solenoid valve; A control device for a forced air combustion device that opens and closes the electromagnetic valve based on a combustion amount set by a combustion amount setting means, the control device comprising a second burner that is directly supplied with electricity to the proportional valve. A control device for a forced air combustion device, characterized in that the current is determined in a predetermined relationship based on the rotational speed of the blower, regardless of whether the electromagnetic valve is opened or closed.