JPH0599426A - Method for controlling amount of air and amount of gas during slow ignition - Google Patents

Abstract

PURPOSE:To provide a method for controlling the amount of air and the amount of gas during a slow ignition capable of performing fast and positive ignition at a burner and preventing the occurrence of a cold water sand phenomenon during the re-discharging of hot water. CONSTITUTION:In an instantaneous hot water feeder comprising a water feeding passage and a hot water discharging passage at a heat exchanging part, a burner for heating the heat exchanging part and a fan for feeding combustion air, after confirmation that a minimum amount of supplied water (MOQ) required for a hot water feeding operation at the start of operation is fed, the operation of the fan is started. When the number of rotation of the fan reaches more than a target number of rotation, the amount of gas corresponding to the amount of air at that time is supplied to perform an ignition. After this operation, the number of rotation of the fan is controlled to the target number of rotation and at the same time the amount of gas is controlled in response to the amount of air fed under the operation of the fan.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an air flow and a gas flow during slow ignition in a momentary water heater, which suppresses rapid ignition to a burner to perform gentle ignition.

[0002]

2. Description of the Related Art Conventionally, a heat exchange section, a water inlet and a hot water outlet connected to both ends of the heat exchange section, a burner for heating the heat exchange section, and a fan for supplying combustion air to the burner are provided. In the instantaneous water heater, when water is started to flow from the water inlet to the heat exchange part when hot water is started, the water is detected and combustion of the burner is started, but there is a risk of explosion ignition, etc. In order to prevent and ignite the burner slowly, the operation control of the fan and the control of the supply gas amount give priority to the supply gas amount. The control method of controlling the air volume is adopted.

An example of a conventional gas amount leading ignition control method will be described with reference to FIG. 3. The minimum water flow rate (MOQ), which is the minimum flow rate required for the instantaneous water heater to perform hot water supply operation.
Check that the water is flowing through and start the fan operation. After confirming that the air flow rate of the fan has reached the target air volume that corresponds to the preset ignition gas volume and is stable, or that it has stabilized at the target rotation speed that guarantees the target air volume, open the gas solenoid valve to open the igniter, etc. The ignition device is turned on to perform the ignition operation, the gas amount and the fan rotation speed are kept constant at a predetermined value, and after confirming the ignition of the burner with an ignition detection device such as a flame rod, the combustion amount according to the load is determined. To the steady combustion operation.

[0004]

However, in the above-described conventional gas amount-leading ignition control method, since it takes a considerable time for the rotation speed of the fan to stabilize (that is, for the air flow to stabilize), ignition occurs. There is a problem that it takes a long time to confirm (see Fig. 4). Especially when re-releasing hot water after stopping combustion once and restarting hot water, only air is blown until the fan speed stabilizes. There has been a problem that the heat exchange section is cooled and a cold water sand phenomenon may occur.

An object of the present invention is to provide a method for controlling the air volume and the gas volume at the time of slow ignition, which can promptly and reliably ignite the burner and prevent the occurrence of the cold water sand phenomenon at the time of re-leaving hot water. is there.

[0006]

In order to achieve the above object, the method of controlling the air flow rate and the gas flow rate at the time of slow ignition of the present invention is a heat exchange section, and a water inlet and a hot water outlet connected to both ends of the heat exchange section. In a momentary water heater with a channel, a burner that heats the heat exchange section, and a fan that supplies combustion air to the burner, the minimum flow rate required for the momentary water heater to perform hot water supply operation at the start of hot water supply operation. After confirming that the minimum amount of water (MOQ) is being passed, the fan operation is started,
When the fan speed reaches or exceeds the target speed (that is, the air volume is higher than or equal to the target air volume), the gas quantity corresponding to the air volume at that time is supplied to perform ignition operation, and then the fan speed is set to the target rotation rate. In addition to the above control, the amount of gas is controlled according to the amount of air blown by the fan, and by controlling the supply of gas in accordance with the amount of air blown by the fan, harmful phenomena such as back and lift blowout are generated. The burner can be reliably ignited without the risk of sudden ignition such as explosion ignition, and the time during which only the fan is operating can be shortened. Occasionally, the heat exchange section is not significantly cooled, and the occurrence of the cold water sand phenomenon can be prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the flowchart of FIG. 1. The minimum water flow rate (MOQ), which is the minimum flow rate required for the instantaneous water heater to perform hot water supply operation, is being passed. Make sure that the fan is running.

The rotation speed of the fan is the target rotation speed (target air volume)
After confirming that the target temperature has been reached, the gas solenoid valve is turned on to supply the gas amount corresponding to the target speed, and the ignition device such as an igniter is turned on to perform the ignition operation, and then the fan speed is set to the target speed. While stabilizing the number, the amount of gas is adjusted according to the fluctuation of the fan rotation speed (that is, fluctuation of the air volume) in the process (see FIG. 2). As a result, it is possible to suppress the occurrence of harmful phenomena such as backing and blowout of the lift during ignition.

After the ignition operation is completed, when the ignition detection device such as the frame rod detects the reliable ignition of the burner,
It shifts to the steady combustion operation and performs hot water supply operation with the combustion amount according to the load.In the steady combustion operation, the gas amount priority control, that is, the supply gas amount is adjusted according to the load, and the supplied gas A control method is used in which the air volume (fan rotation speed) is adjusted according to the volume.

With the above construction, by controlling the supply of the gas quantity in correspondence with the air quantity only at the time of ignition, it is possible to suppress the occurrence of harmful phenomena such as back and lift blowout, and to make rapid ignition such as explosion ignition. There is no fear of causing
The burner can be reliably ignited, and the time during which only the fan is operating is shortened, so the heat exchange section is not significantly cooled during re-leaving hot water, and the occurrence of the cold water sand phenomenon is prevented. be able to.

[0011]

Since the present invention is constructed as described above, it has the following effects. It is possible to prevent the occurrence of harmful phenomena such as back and blowout of the lift by controlling the supply by making the gas flow correspond to the air flow at ignition.
The burner can be ignited reliably without the risk of explosive ignition or other rapid ignition, and the time during which only the fan is operating is shortened. It is possible to prevent the occurrence of the cold water sand phenomenon without being cooled.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of a control method of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a fan rotation speed and a gas amount according to the control method of the present invention.

FIG. 3 is a flowchart showing an operation of a conventional control method.

FIG. 4 is a characteristic diagram showing a relationship between a fan rotation speed and a gas amount according to a conventional control method.

Claims (1)

[Claims] 1. A heat exchange part, a water inlet and a hot water outlet connected to both ends of the heat exchange part, a burner for heating the heat exchange part,
In a momentary water heater equipped with a fan that supplies combustion air to the burner, the minimum amount of water that is the minimum flow rate required for the hot water heater to perform hot water supply at the start of the hot water supply operation. After confirming, start the operation of the fan,
A gas amount corresponding to the amount of air when the fan speed reaches a predetermined value or more is supplied to perform ignition operation, and then the fan speed is controlled to the target speed, and according to the amount of air blown by the fan. A method for controlling the amount of air and the amount of gas at the time of slow ignition, which is characterized by controlling the amount of gas by means of control.