JPH0454134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion apparatus that includes a proportional control valve that supplies fuel to a burner and a blower that supplies air for combustion to the burner.

[Prior art] Fuel such as gas or oil is supplied to the burner according to the opening degree of a proportional control valve, and combustion air is supplied to the burner using a blower. A combustion bed device is used.

Conventionally, in this type of device, fuel is supplied to the burner by setting the opening degree of the proportional control valve according to the calorific value setting means (for example, temperature setting means) set by the user, and air is supplied to the burner by the blower. is supplied, and the burner burns the fuel. At this time, the amount of combustion air supplied by the blower is controlled according to the output of a combustion sensor (for example, a thermocouple) that detects the state of the burner flame.

[Problems to be Solved by the Invention] However, in conventional combustion devices, as described above, the circuit that controls the proportional control valve and the circuit that controls the blower are separate and independent circuits. For example, when the calorific value setting means is changed, the opening degree of the proportional control valve changes quickly in response to the change in the calorific value setting means, but the amount of combustion air supplied by the blower is first changed by the opening of the proportional control valve. The combustion sensor detects changes in the flame due to changes in temperature, and the blower's air volume is changed based on the change in the combustion sensor's output, so there is a problem that the blower's response to changes in the heat value setting means is very poor. was.

In addition, immediately after changing the calorific value setting means, combustion air corresponding to the fuel supplied to the burner is not supplied to the burner, so proper combustion does not occur and toxic exhaust gases such as CO are generated. There was a possibility of doing so.

The present invention was made in view of the above circumstances, and
The purpose is to provide a combustion device that can quickly match the opening degree of the proportional control valve and the amount of combustion air supplied by the blower by applying changes in the calorific value setting means.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a burner, a proportional control valve for supplying fuel to the burner, and a blower for supplying air for combustion to the burner. , a combustion sensor that detects the combustion state of the burner, a calorific value setting means, a proportional valve control circuit that controls the opening degree of the proportional control valve according to the setting of the calorific value setting means, and the calorific value setting means. a blower control circuit that controls the amount of combustion air supplied by the blower according to the settings of the blower, and at least one of the proportional valve control circuit and the blower control circuit receives the output of the combustion sensor,
The technical means is to constantly perform feedback control of the proportional control valve or the blower to control the air-fuel ratio of the burner flame to a set value.

[Operation and Effects of the Invention] The present invention having the above configuration controls the proportional valve control circuit according to the setting state of the calorific value setting means, so that when the calorific value setting means is changed, the opening degree of the proportional control valve is quickly adjusted. changes in accordance with changes in the calorific value setting means. On the other hand, by controlling the amount of air blown by the combustion blower according to the setting state of the calorific value setting means, when the calorific value setting means is changed, the amount of combustion air supplied by the blower changes quickly. As a result, the opening degree of the proportional control valve and the amount of combustion air supplied by the blower can be instantly set to appropriate values in response to changes in the calorific value setting means. The amount of heat generated can be changed by changing the amount of heat generated, and the flame can always be combusted at an appropriate air-fuel ratio.

Also, if the flame is not combusted at the proper air-fuel ratio,
At least one of the proportional valve control circuit and the blower control circuit performs feedback control of the air-fuel ratio of the flame in response to the output of the combustion sensor, thereby controlling the amount of gas supplied to the burner or the combustion supplied to the burner. The amount of air supplied is corrected to an appropriate value, and the flame is combusted at an appropriate air-fuel ratio.

[Example] Next, an example in which the present invention is applied to a gas water heater will be described based on the drawings.

FIG. 2 shows a schematic diagram of a gas water heater.

This gas water heater 1 consists of a combustion section 3 equipped with a heat exchange section 2, a gas supply path 4, and an electronic control circuit 5.

The combustion section 3 includes a combustion chamber 32 equipped with a surface combustion type burner 31 made of ceramic, and a combustion air blower 33 installed at the lower part of the combustion chamber 32 to supply combustion air to the burner 31. A supply section 34 and a burner 3 provided above the combustion chamber 32.
Exhaust port 3 for exhausting the combustion gas burned in step 1
5. The heat exchange section 2 includes a fin 21 that increases heat exchange efficiency and a water supply pipe 22, and is disposed between a burner 31 and an exhaust port 35 to burn water sent from upstream of the water supply pipe 22. Room 3
It exchanges heat with the combustion gas inside 2 and flows out as hot water.

The gas supply path 4 is provided upstream of a gas jetting nozzle 41 that discharges gas upstream of the burner 31 and a gas supply pipe piping 42 that supplies gas to the gas jetting nozzle 41, and is opened and closed when energized or de-energized. An on-off valve 43 and a governor valve 44 that is provided downstream of this on-off valve 43 and adjusts the flow rate of gas.
and a proportional control valve 45 which is provided on the downstream side of the governor valve 44 and whose opening ratio is varied depending on the amount of current supplied.

The electronic control circuit 5 includes a spark electrode 51 that emits sparks on the top surface of the burner 31 during ignition, a thermocouple 52 that is a combustion sensor that detects the oxygen supply state of the flame above the burner 31, and a water supply pipe 22 of the heat exchange section 2. A water temperature sensor 53 attached to the outflow section to detect the water temperature, a temperature control volume 54 operated by the user to set the temperature of the water flowing out from the water supply pipe 22 of the heat exchange section 2, a blower 33, an on-off valve 43, a proportional It drives and controls the control valve 45 and the like.

Next, control of the opening ratio of the proportional control valve 45 and control of the amount of combustion air supplied by the blower 33 will be explained based on the block diagram shown in FIG.

The output signal from the water temperature sensor 53 and the reference value obtained by the temperature adjustment volume 54 are compared and amplified to adjust the temperature of the hot water obtained from the gas water heater 1. )
The proportional control valve 45 A proportional control circuit 62 that controls the opening ratio of the blower 33 controls the amount of electricity supplied to the blower 33 according to the output of the heat generation setting circuit 61 and the output of the thermocouple, and controls the opening ratio of the proportional control valve 45. A blower control circuit 63 that controls the supply amount of combustion air by
Equipped with.

The gas water heater 1 of this embodiment is equipped with the electronic control device 5 as described above, so that the user can change the temperature of the hot water supplied from the gas water heater 1 by operating the temperature control volume 54. When desired, the output of the calorific value setting circuit 61 changes quickly due to changes in the temperature control volume 54, so the proportional valve control circuit 62 supplies the output to the proportional control valve 45 according to the change in the output of the calorific value setting circuit 61. The opening degree of the proportional control valve 45 is changed by changing the amount of current applied. On the other hand, when the output of the heat generation setting circuit 61 changes, the blower control circuit 63 changes the amount of electricity supplied to the blower 33 in accordance with the output change.
The blower 33 changes the amount of combustion air supplied in accordance with the change in output. In other words, when the operator operates the temperature control volume 54, the opening degree of the proportional control valve 45 and the rotational speed of the blower 33 begin to change simultaneously, and hot water at the temperature desired by the operator is supplied more quickly than in the gas water heater 1. Supplied.

At this time, the opening degree of the proportional control valve 45 and the blower 33
Since the rotational speed of the combustion air starts to change at the same time, the ratio between the amount of gas supplied by the proportional control valve 45 and the amount of combustion air supplied by the blower 33 is maintained at an appropriate value.
The flame is always burned at the proper air-fuel ratio.

On the other hand, the water temperature sensor 53 constantly monitors the temperature of hot water supplied from the gas water heater 1.
The heating value setting circuit 61 controls the proportional valve control circuit 62 so that the temperature detected by the temperature control valve 3 matches the temperature set by the temperature control volume 54, so that the opening degree of the proportional control valve 45 is adjusted to the temperature detected by the water temperature sensor 53. Correction control is performed at a speed approximately corresponding to the temperature detection speed,
The temperature of the hot water supplied from the gas water heater 1 is corrected to the temperature set by the temperature adjusting volume 54.

Further, for example, if the flame does not burn at an appropriate air-fuel ratio due to a change in the composition of the supplied gas, or if the flow resistance of the combustion air intake or exhaust port increases, the proportional control valve 45 may If the combustion air set according to the opening degree is not supplied and the flame does not burn at an appropriate air-fuel ratio, the blower control circuit 63 is activated according to the output of the thermo couple 52.
controls the amount of electricity supplied to the blower 33 and corrects the amount of combustion air supplied, so the flame is always burned at an appropriate air-fuel ratio.

Note that the blower control circuit 63 includes the gas water heater 1
When the thermocouple 52 is ignited, the input from the thermocouple 52 is canceled for, for example, 10 seconds until the output of the thermocouple 52 becomes stable. There is.

FIG. 3 shows another embodiment of the invention.

In the above embodiment, when the temperature adjustment volume 54 is operated, the amount of electricity applied to the proportional control valve 45 and the amount of electricity applied to the blower 33 are changed simultaneously. However, normally, the response speed of the blower 33 is changed. changes smoothly compared to the response speed of the proportional control valve 45. Therefore, if the amount of current to the proportional control valve 45 and the blower 33 starts to change at the same time, the proportional control valve 45 will change immediately after the temperature adjustment volume 54 is operated. The change in the rotational speed of the blower 33 did not follow the change in the opening of the fan, and the air-fuel ratio sometimes changed slightly, although not as much as in the past. Therefore, in this embodiment, a delay circuit 64 is provided on the input side of the proportional control valve 45 to delay the input signal. As a result, the air blower 3 changes gradually.
Since the opening degree of the proportional control valve 45 can be changed during the rotational speed change in step 3, the change in the air-fuel ratio immediately after the temperature control volume 54 is operated can be kept smaller than in the above embodiment. I can do it.

In addition, in the above embodiment, when the flame does not burn at an appropriate air-fuel ratio, the output of the combustion sensor is used to correct the amount of combustion air supplied by the blower. The air-fuel ratio of the flame can be controlled to an appropriate value by correcting the gas supply amount, or the output of the combustion sensor can be used to feed back control both the proportional valve control circuit and the blower control circuit. The air-fuel ratio of the flame may be controlled to an appropriate value by correcting and controlling both the opening degree of the combustion air and the supply amount of combustion air.

Further, in the above embodiment, an example was shown in which the present invention was applied to a water heater, but the present invention may be applied to other combustion devices such as a heating device.

Furthermore, although the above embodiments use gas as fuel, the present invention may be applied to other combustion devices that use kerosene or the like as fuel.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control circuit according to the present invention, FIG. 2 is a schematic diagram of a gas water heater, and FIG. 3 is a block diagram of a control circuit showing another embodiment according to the present invention. In the diagram 1...Gas water heater, 31...Burner, 3
3...Blower, 42...Gas supply piping, 45...
Proportional control valve, 52...Thermocouple, 53...
Water temperature sensor, 54...Temperature adjustment volume,
61... Calorific value setting circuit, 62... Proportional valve control circuit, 63... Blower control circuit.

Claims (1)

[Claims] 1: a burner; a proportional control valve that supplies fuel to the burner; a blower that supplies combustion air to the burner; a combustion sensor that detects the combustion state of the burner; a proportional valve control circuit that controls the opening degree of the proportional control valve according to the setting of the calorific value setting means; and a proportional valve control circuit that controls the amount of combustion air supplied by the blower according to the setting of the calorific value setting means. and a blower control circuit for controlling the proportional control valve or the blower, at least one of the proportional valve control circuit or the blower control circuit always performing feedback control of the proportional control valve or the blower in response to the output of the combustion sensor, A combustion device that controls the air-fuel ratio of the burner flame to a set value. 2. The combustion device according to claim 1, wherein the combustion sensor is a thermocouple that detects the temperature of the flame and the state of air supply to the flame.