JPH04350417A - Forced air supplying and discharging type indoor hot water feeder - Google Patents

Abstract

PURPOSE:To perform always a sufficient and appropriate pre-purging in a hot water feeder for performing a pre-purging operation for replacing air in the device with surrounding air before ignition in the device by a method wherein a pressure of air sucked from the surrounding atmosphere into the device is detected, and a high or a low state of the pre-purging operation is changed in response to the result of detection. CONSTITUTION:As an operation switch is turned on, a controller 50 at fist drives a blower fan 11 at a relative low number of rotation so as to perform a pre-purging operation. Then, the controller 50 drives an igniter 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, during the pre-purging operation, the controller 50 judges whether an air pressure switch 60 disposed within an air discharging cylinder 30 is turned off or not. In the case that the air pressure switch 60 is turned on, since the air applies a reverse pressure within the air discharging cylinder 30, the controller 50 increases the number of rotation of the air blower fan 11. With such an arrangement as above, a sufficient pre-purging against the reversing pressure is carried out and a positive and normal ignition is performed.

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, forced air supply and exhaust water heaters for indoor use have been provided that use a wind pressure switch to detect the pressure of air trying to enter the water heater. All of the controls involved changing the fan rotation speed in response to changes in wind pressure during steady combustion.

0003

[Problems to be Solved by the Invention] However, in the above-mentioned conventional water heater, ignition is performed at a constant pre-purge rotation speed in the ignition sequence, regardless of the presence or absence of the reverse pressure of outside air applied to the interior of the water heater. For this reason, there is a problem in that the ignition cannot be properly and reliably ignited under conditions of large back pressure such as in strong winds. 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,
The purpose of the present invention is to provide an indoor forced air supply/exhaust type water heater that can reliably and normally ignite.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the indoor forced air supply/exhaust water heater of the present invention is an indoor forced water heater that performs a pre-purge operation to replace the air inside the water heater with outside air prior to ignition. The water heater is a supply/exhaust type water heater, and is equipped with a wind pressure switch that detects the pressure of air blown into the vessel from the outside, and is configured to change the pre-purge rotation speed of a blower fan according to the pressure detected by the wind pressure switch. It is characterized by

[0006]

[Operation] Since the pre-purge rotation speed of the blower fan is changed according to the pressure detected by the wind pressure switch, the pre-purge rotation speed can be increased accordingly as the back pressure is generated and increases. Therefore, prior to ignition, the air inside the vessel can be reliably discharged and replaced against back pressure and the like. Also, the airflow inside the container can be kept stable against wind blowing. Therefore, reliable and normal ignition can be ensured without being affected by external airflow.

[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 flowchart showing a first control example of ignition operation when hot water is used, and Fig. 3 is a flowchart showing a first control example of ignition operation when hot water is used. It is a flowchart which shows a 2nd example of control.

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 of the ignition operation during hot water supply by the controller 50 will be explained with reference to FIG. Now, the operation switch is turned on by a remote controller (not shown) or the like (step 101), the hot water tap (not shown) is opened (step 102), and when the minimum operating water flow flows through the hot water pipe, a water flow sensor (not shown) is turned on (step 103). ), the ignition sequence is started by inputting an on signal to the controller 50.

First, the controller 50 turns on the blower fan 11 (step 104). As a result, the blower fan 1
1 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. During this operation, it is determined whether the wind pressure switch 60 is off (step 105), and if it is off, the pre-purge rotation speed of the fan 11 is set to the normal value X (step 106), and if it is on, the fan 11 is turned off. The pre-purge rotation speed is set to a value X+a (step 107) that is higher than the normal speed. When the wind pressure switch 60 is on, a back pressure is applied to the inside of the container due to wind or the like, so by increasing the rotation speed of the fan 11, pre-purge can be performed against the back pressure. If the rotation speed is not increased, the pre-purge will be insufficient. When the rotation speed sensor (not shown) attached to the blower fan 11 detects the pre-purge rotation speed (steps 106 and 107
), the controller 50 turns on the igniter 14 and opens the fuel supply valve 13 (step 108). As a result, the burner 12 is ignited and combustion starts, resulting in steady combustion. After the blower fan 11 is ignited, its rotational speed is further increased to a steady rotational speed.

Next, a second example of control of the ignition operation when hot water is used will be explained with reference to FIG. In this example, two wind pressure switches, a first wind pressure switch and a second wind pressure switch, are provided to more precisely control the air blowing during ignition and during steady combustion. The operation switch is turned on by a remote controller (not shown) (step 201).
, a hot water tap (not shown) is opened (step 202),
When the minimum operating amount of water flows through the hot water pipe, a water amount sensor (not shown) turns on (step 203), and an on signal is input to the controller 50, thereby starting an ignition sequence.

In the ignition sequence, first the controller 50
turns on the blower fan 11 (step 204). 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. However, before that, the pre-purge rotation speed is changed by the first and second wind pressure switches according to the degree of wind pressure applied from the outside to the inside of the container. That is, it is first determined whether the first wind pressure switch with the lower set pressure is off (step 205).
When it is off (in this case, the second wind pressure switch is naturally off), there is no external back pressure applied to the inside of the vessel, so the breipurge rotation speed is set to the normal value X (
Step 206), when this value X is reached, the igniter 14
is turned on and the fuel supply valve 13 is opened (step 210
). On the other hand, if the first wind pressure switch is on, it is determined whether or not the second wind pressure switch, which has a higher set pressure, is off (step 207). A value larger by an appropriate value a (X+a)
When this value X+a is reached, the igniter 14 is turned on and the fuel supply valve 13 is opened (step 210). Furthermore, when the second wind pressure switch is also on, the back pressure inside the vessel from the outside is also quite high, so the pre-purge rotation speed is set to a value (X+b) higher than the above-mentioned X+a (step 209), and this value X+b is set to At that point, the igniter 14 is turned on and the fuel supply valve 13 is opened (step 210). As a result, the burner 12 is ignited and combustion begins. After ignition, the blower fan 11 further increases its rotational speed to a steady rotational speed Y.

During steady combustion, the fuel is proportionally controlled according to the required calories (step 211). During this steady combustion, the fan 11 normally operates at a steady rotational speed Y
However, if the first wind pressure switch is on (step 212), it is further determined whether or not the second wind pressure switch is off (step 213), and if it is off, the fan rotation speed is set to the normal speed. A value that is larger than the value Y by an appropriate value c (
Y+c) (Step 214), and if the second wind pressure switch is also on, the fan rotation speed is set to a value (Y+d) higher than Y+c (Step 215).
. In this way, by providing multiple stages of fan rotation speed according to the external wind pressure applied to the inside of the vessel, the airflow condition and air pressure inside the vessel can be adjusted even when the influence of a slight wind to a considerably strong wind is affected. It is possible to maintain good exhaust gas discharge, prevent blow-off and incomplete combustion, and ensure good combustion. Conventionally, wind pressure detection in a steady state was performed using a single wind pressure switch, and when reverse pressure occurred, the fan rotation speed was simply increased by one step. For example, 20 m/s) could not be satisfied. Use two wind pressure switches to change the fan rotation speed from the steady state to 2.
By making it possible to step up the combustion process, it is now possible to perform combustion that can withstand strong winds such as building winds.

[0014]

Effects of the Invention The present invention has the above-described configuration and operation, and according to the indoor forced air supply/exhaust type water heater according to claim 1, a wind pressure switch is provided to detect the pressure of air blown into the water heater from the outside. The pre-purge rotation speed of the blower fan can be changed according to the pressure detected by the wind pressure switch, so the pre-purge rotation speed can be increased according to the occurrence and magnitude of back pressure. Ignition can be performed reliably and normally even under reverse pressure.

[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 flowchart showing a first control example of ignition operation during hot water supply use.

FIG. 3 is a flowchart showing a second control example of ignition operation 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 pre-purge operation to replace the air inside the vessel with outside air prior to ignition, comprising a wind pressure switch that detects the pressure of air blown into the vessel from the outside. 1. An indoor forced air supply/exhaust type water heater, characterized in that the indoor forced air supply/exhaust water heater is configured to change the pre-purge rotation speed of a blower fan according to the pressure detected by the wind pressure switch.