JPH04350416A - Forced air supplying or discharging type indoor hot water feeder - Google Patents

Abstract

PURPOSE:To prevent an explosion type ignition positively at a time of reignition after an intermediate fire extinction in a hot water feeder for performing a purging operation for replacing air in the device with surrounding atmosphere before ignition and after extinction by a method wherein a more powerful purging operation is carried out in the case that a flame is extinguished in the midway of the combustion. CONSTITUTION:When an operation switch is turned on, a controller 50 at first drives a blower fan 11 at a relative low number of rotation so as to perform a prepurging operation. Then, the controller 50 drives an ignition device 14 and at the same time releases a fuel supplying valve 13. As a result, a burner 12 is ignited and combustion is started. In this case, as air is blown from an exhaust cylinder 30 during combustion to blew off the flame, the controller 50 closes the fuel supplying valve 13. In the case that the number of times of reignition is more than a specified number of times, the operation is stopped for a sake of safety. In turn, in the case that the number of times of reignition is less than the specified number of times, the controller 50 sets once the number of rotation of the blower fan 11 to its maximum value. With such an arrangement, an incomplete combustion gas within the exhaust cylinder 30 is forcedly purged.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced air supply/exhaust type water heater placed indoors.

0002

[Prior Art] Conventionally, in indoor forced air supply and exhaust type water heaters, during pre-purge before ignition and post-purge after extinguishing, the number of pre-purge rotations by a blower fan,
The post purge rotation speed was set to a relatively low constant rotation speed.

0003

[Problems to be Solved by the Invention] However, in the above-mentioned conventional water heaters, if the combustion goes out midway due to strong winds, etc., incompletely combusted gas tends to remain in the exhaust stack or inside the container, causing an explosion when it is re-ignited. There was a problem with ignition. This problem is especially important when used on high floors where strong winds are likely to blow.

[0004] Therefore, the present invention solves the drawbacks of the above-mentioned prior art, and even when used on high floors or under strong winds,
To provide an indoor forced air supply/exhaust type water heater that does not cause explosive ignition when re-igniting after partially extinguishing the flame.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the indoor forced air supply/exhaust type water heater of the present invention performs a purge operation to replace the air inside the device with outside air before ignition and after extinguishing the fire. This indoor forced air supply/exhaust type water heater is characterized in that the air purging operation performed after combustion is extinguished midway is performed more forcefully than normal.

[0006]

[Effect] The air purge operation that is performed after the flame is extinguished during combustion is performed more powerfully than usual, so the incompletely combusted gas remaining in the exhaust stack and inside the chamber is removed from the back pressure caused by wind, etc. It resists and is forcefully ejected out of the exhaust stack. Therefore, even when the flame is re-ignited after the flame has been extinguished, the inside of the vessel is sufficiently replaced with fresh air, and explosive ignition is prevented.

[0007]

[Embodiment] Fig. 1 is a cross-sectional configuration diagram of a water heater showing an embodiment of the present invention, Fig. 2 is a control flowchart showing a first example of ignition operation during hot water supply and operation after extinguishing the flame during use, and Fig. 3
is a control flowchart showing a second example of the ignition operation and the operation after the flame is extinguished during hot water supply use.

A hot water supply can 10 and a bath can 20 are provided in the case 1. The hot water supply can 10 and the bath can 20 are equipped with blower fans 11 and 21 and a burner 12, respectively.
, 22, fuel supply valves 13, 23, igniters 14, 24, and heat exchangers 15, 25 are installed. The exhaust pipe 30 common to both the can bodies 10 and 20 and the supply pipe 40 provided in the case 1 are extended to the outside, and the wall surface of the house etc.
desired by others. Reference numeral 50 denotes a controller with a built-in microcomputer, which receives commands from a remote controller (not shown), obtains information from sensors in various parts of the appliance, and instructs each part of the appliance to perform predetermined operations. 60 is a wind pressure switch installed inside the exhaust pipe 30.

Next, a first example of control by the controller 50 of the ignition operation during hot water supply and the operation after the flame is extinguished will be explained along with FIG. 2. The operation switch is turned on by a remote controller (not shown) (step 10).
1) When the hot water tap (not shown) is opened and the minimum operating water flow flows through the hot water pipe, the water amount sensor (not shown) is turned on (step 102), and the on signal is input to the controller 50, thereby starting the ignition sequence. Ru. First, the controller 50 turns on the blower fan 11 (step 103). As a result, the blower fan 11 starts rotating, and the number of rotations gradually increases. The period of time until the rotational speed reaches a predetermined relatively low prepurge rotational speed is defined as the prepurge operation time before ignition. When the rotation speed sensor (not shown) attached to the blower fan 11 detects the pre-purge rotation speed (step 104), the controller 50 turns on the igniter 14 and opens the fuel supply valve 13 (step 105). As a result, the burner 12 is ignited and combustion begins. After the blower fan 11 is ignited, its rotational speed is further increased to a steady rotational speed.

During combustion, when wind or the like enters from the exhaust stack 30 and blows out the flame (step 106), a flame sensor (not shown) detects the extinguishment of the flame and inputs this to the controller 50. As a result, the controller 50 closes the fuel supply valve 13 (step 107), and further determines whether the number of reignitions has been a certain number, for example, two times or less (step 108), and if it has exceeded two times, the controller 50 closes the fuel supply valve 13 (step 107). teeth,
For safety reasons, the operation is stopped (step 109). If the number of re-ignitions is two or less, the controller 50 temporarily sets the rotation speed of the blower fan 11 to the maximum (step 110). As a result, the incompletely combusted gas in the exhaust stack 30 and inside the vessel is strongly purged (exhausted), and the inside of the vessel is replaced with fresh air. After performing the purge for a certain period of time (an appropriate time for purging the exhaust stack and the inside of the container, for example, less than several tens of seconds is preset) (step 111), the controller 50 turns on the operation switch and the water volume switch. The re-ignition sequence is started on the premise that the engine is present (steps 112 and 113). If the operation switch is off or the water flow sensor is off, the operation will be stopped (step 1).
09).

The re-ignition sequence begins with the controller 50
The rotation speed of the blower fan 11 is set to the pre-purge rotation speed (step 114), and when the rotation speed of the fan 11 has decreased to the pre-purge rotation speed (step 115), the igniter 14 is turned on again and the fuel is turned on. Supply valve 13
is reopened (step 116). As a result, burner 1
2 is reignited.

Next, a second control example of the ignition operation during hot water supply and the operation after the flame is extinguished in the middle will be explained with reference to FIG. 3 when the wind pressure switch 60 is used. The operation switch is turned on by a remote controller (not shown) (step 2).
01), a water amount sensor (not shown) is turned on (step 202).
), the ignition sequence is started. First, the controller 50 turns on the blower fan 11 (step 203). As a result, the blower fan 11 starts rotating, and the number of rotations gradually increases. The period of time until the rotational speed reaches a predetermined relatively low prepurge rotational speed is defined as the prepurge operation time before ignition. The pre-purge rotation speed varies depending on whether the wind pressure switch 60 provided in the exhaust stack 30 is in the on state or the off state. In other words, when the wind pressure switch 60 is off and no counter pressure is applied to the inside of the vessel from the outside, the igniter 14 is set to the normal value X, and when this value X is reached, the igniter 14 is turned off.
is turned on and the fuel supply valve 13 is opened (step 204
, 205, 207). On the other hand, when the wind pressure switch 60 is on and a counter pressure is applied to the inside of the device from the outside, the blip-purge rotation speed is set to a value larger than the normal value X by an appropriate value α, and reaches this value X+α. At that point, the igniter 14
is turned on and the fuel supply valve 13 is opened (step 204
, 206, 207). As a result, the burner 12 is ignited and combustion begins. After the blower fan 11 is ignited, its rotational speed is further increased to a steady rotational speed.

During combustion, when wind or the like enters through the exhaust stack 30 and blows out the flame (step 208), a flame sensor (not shown) detects the extinguishing of the flame and inputs this to the controller 50. As a result, the controller 50 closes the fuel supply valve 13 (step 209), and further determines whether the number of reignitions has been a certain number, for example, 2 times or less (step 210), and if it has exceeded 2 times, the controller 50 closes the fuel supply valve 13 (step 209). teeth,
For safety reasons, the operation is stopped (step 211). Further, if the number of reignitions is two or less, the controller 50 controls the blower fan 11 on the condition that the wind pressure switch 60 is off (no back pressure is generated) (step 212).
The rotation speed is once set to the maximum (step 213). As a result, the incompletely combusted gas in the exhaust stack 30 and inside the vessel is reliably and strongly purged (exhausted), and the inside of the vessel is replaced with fresh air. After performing the purge for a certain period of time (an appropriate time to purge the exhaust stack and the inside of the chamber, for example, less than several tens of seconds) (step 214), the controller 50 turns on the operation switch and the water volume switch. The re-ignition sequence is started on the premise that the engine is present (steps 215 and 216). If the operation switch is off or the water flow sensor is off, the operation is stopped (step 21).
1).

The re-ignition sequence begins with the controller 50
As a result, the rotation speed of the blower fan 11 is set to the pre-purge rotation speed X (step 217), and after the rotation speed of the fan 11 has decreased to the pre-purge rotation speed (step 2
18), wait until the wind pressure switch 60 is turned off (step 219), turn on the igniter 14 again, and turn on the fuel supply valve 1.
3 (step 220). This ensures that the burner 12 is re-ignited without any back pressure being applied.

[0015] Furthermore, purging after the above-mentioned intermediate quenching (step 1)
10, 213), the rotation speed of the fan 11 is set to the maximum value, but it is not necessarily necessary to set the rotation speed to the maximum value, and an appropriate rotation speed higher than the prepurge rotation speed can be adopted. Of course, a high rotational speed is preferable to ensure that residual gas is exhausted. Further, in each of the above embodiments, the operation when hot water is supplied has been described, but the re-ignition control operation when using the bath can body 20 to heat a bath is also the same.

[0016]

Effects of the Invention According to the indoor forced air supply/exhaust type water heater according to the present invention, which has the above-described configuration and operation, in the air purge operation performed after combustion is extinguished midway, Since the purge operation is configured to be more powerful than normal, incompletely burned gas remaining in the exhaust stack and inside the chamber is strongly forced out of the exhaust stack against back pressure caused by wind, etc. is discharged. Therefore, when re-igniting after partially extinguishing the flame, the inside of the vessel is replaced with sufficient fresh air, explosion and ignition is reliably prevented, and re-ignition can be carried out smoothly.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram of a water heater showing an embodiment of the present invention.

FIG. 2 is a control flowchart showing a first example of an ignition operation and an operation after extinguishing the flame during hot water supply use.

FIG. 3 is a control flowchart showing a second example of the ignition operation and the operation after extinguishing the flame during hot water supply use.

[Explanation of symbols]

1 case 10 Can body for hot water supply 11, 21　Blower fan 12, 22 Burner 13, 23 Fuel supply valve 14, 24 Igniter 15, 25 Heat exchanger 30 Exhaust pipe 40 Supply cylinder 50 Controller 60 Wind pressure switch

Claims (1)

[Claims] Claim 1: An indoor forced air supply/exhaust type water heater that performs a purge operation to exchange the air inside the vessel with outside air before ignition and after extinguishing the fire, the air purging being carried out after the flame is extinguished during combustion. An indoor forced air supply/exhaust type water heater characterized in that the purge operation is performed more powerfully than usual.