JP3008614B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater such as a gas instantaneous water heater for home use.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a gas instantaneous water heater as an example of the prior art. Water is supplied from a water inlet 51, passes through a water amount detection device 52 and a constant water amount valve 53, absorbs heat in a heat exchanger 54 of the heat exchange device E, and is supplied outside the machine from a hot water supply port 55. Gas is supplied from a gas inlet 56 and supplied from a gas solenoid valve 57 and a gas proportional valve 58 for controlling a fuel supply amount, and is burned by a burner 59 to generate heat. Air required for combustion is supplied by a combustion blower 60, and combustion gas generated by the combustion is discharged from an exhaust port 61. The control device 62 determines the amount of air supplied to the combustion blower 60 by the gas proportional valve 58.
Is controlled by the number of rotations based on data stored in correspondence with the gas supply amount to the gas.

[0003]

However, in the above-described configuration, for example, even if the heat exchange fins 54a of the heat exchanger 54 are clogged with soot or the like, the combustion blower 1 is simply operated as in the normal state.
In order to keep the number of revolutions of 0 constant, the work amount of the combustion blower 60 decreases, and the amount of air required for combustion becomes insufficient. As a result, there are problems such as the burner 59 becoming incompletely burned, resulting in uneconomical operation with low combustion efficiency, and accelerated soot clogging to shorten the service life.

Accordingly, the present invention provides a water heater capable of coping with soot clogging of a heat exchanger.

[0005]

Means for Solving the Problems In order to achieve the above object, a water heater according to the present invention burns combustion air from a blower and fuel from a fuel control valve in a combustion chamber cut off from outside air. A heat exchanger that absorbs heat from the combustion gas and outputs hot water; a pressure detection device that detects a pressure difference between the combustion gas before and after the heat exchanger as a ventilation resistance through which the combustion gas passes through the heat exchanger; A data storage unit that matches the pressure difference and the hot water supply output signal corresponding to the hot water supply load, and stores a proper combustion ratio of fuel and air for maintaining good combustion; It has a supply capacity larger than the air amount of the appropriate combustion ratio corresponding to the output instruction signal,
When the pressure difference has increased to a predetermined value due to use progress, a blower that supplies the same amount of air as in the initial use, a detection signal of a pressure detection device, and a proper combustion from a data storage corresponding to the hot water supply output instruction signal. Driving means for instructing and outputting the fuel supply amount of the ratio to the fuel control valve and the air amount to the blower,
The above-mentioned drive means that the pressure detection device corresponds to the maximum supply fuel
Instructs outputs the maximum supply capacity to the detected values blowing becomes impossible that the blower, the reduction in the fuel control valve to the fuel supply amount becomes proper combustion ratio corresponds to the maximum supply capacity of the blower
This is a configuration to make it.

[0006]

[0007]

With the configuration described above, the water heater according to the present invention has the following features.
When the heat exchanger is used and unburned impurities or carbon in the fuel adheres and accumulates, and the ventilation resistance of the combustion gas becomes larger than the initial stage of use, the pressure detecting device detects the ventilation resistance as a pressure difference. The drive unit that receives the detection signal adapts the detection signal and the hot water supply output instruction signal from the data stored in the data storage, and reads and instructs the fuel supply amount to the fuel control valve and the air amount to the blower according to an appropriate combustion ratio. Even if the heat exchanger is clogged due to adhesion and deposition of unburned carbon or the like, good combustion efficiency equivalent to that at the beginning of use can be maintained, and an energy saving effect is exhibited. In addition, this effect is achieved because the blower has a larger supply capacity than at the beginning of use, so that the pressure detected by the pressure detecting device is minimized.
It can be continued until the air supply corresponding to the large supply of fuel increases to a value at which the air supply becomes impossible, and the acceleration period of the generation of unburned carbon or the like due to insufficient air combustion can be extended to extend the service life. In addition, the pressure detection device cannot blow air corresponding to the maximum fuel supply.
When the value is detected and the clogging of the heat exchanger due to unburned carbon etc. cannot be handled by increasing the air volume of the blower, the drive means that has received the detection signal of the pressure detection device indicates the air volume of the blower to the maximum capacity. However, it is not possible to cope with a hot water supply load adapted to the hot water supply output instruction signal by reducing the fuel supply amount of the fuel control valve,
Provide good combustion with proper combustion ratio. In addition, a large amount of dangerous CO gas and unburned carbon can be avoided due to incomplete combustion due to lack of air. Can provide performance.

[0008]

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gas instantaneous water heater will be described as an embodiment of the present invention with reference to the drawings.

FIG. 1 shows the overall construction, in which water is supplied from a water inlet 1 and a constant water quantity valve 3 for controlling the water quantity and a water quantity detection device 3
Then, the heat is absorbed by the heat exchanger 5 of the combustion chamber 4 and the hot water is supplied from the hot water supply port 6 to the outside of the machine. Gas is supplied from a gas inlet 7 and a gas solenoid valve 9 for controlling opening and closing of a gas passage 8 and a gas proportional valve 10 as a fuel control valve for proportionally adjusting the gas supply amount.
The fuel is burned by the burner 15 to generate heat. Air required for combustion is supplied by a blower 11, and combustion gas 12 generated by combustion is exhausted from an exhaust port 13. The blower 11 airtightly passes through the mounting port 14 of the combustion chamber 4 and is tightly fixed to the burner 15, and the gas path 8 is fixed so as to pass airtightly through the mounting port 17. The combustion chamber 4 has an airtight structure in which only the exhaust port 13 is opened, and performs a so-called pressurized combustion that is higher than the atmosphere due to a blowing pressure generated by pushing the blower 11. The heat exchanger 5 has a large number of fins 19 for heat absorption in a water pipe 18 for heating by supplying feed water.

The pressure difference Δp = p _O −p between the pressure p _O between the blower 11 and the burner 15 and the outlet pressure p of the heat exchanger 5 is detected by the pressure detecting device 20. Each of the pressures p _O and p incorporates a pressure detection thin tube 21 as shown in the figure, and opens into the gas so that the static pressure of the gas flow can be detected. Pressure detector 20
Are electrically connected to the control device 21 as shown by the broken lines in the figure to transmit and receive signals. The control device 21 stores data by a pressure determination device 22 that receives a detection signal from the pressure detection device 20, a driving unit 23 that outputs a fuel supply amount to the gas proportional valve 9, a driving current to the blower 11, and an microcomputer. And a data storage 24 for performing the operation. An operation panel 26 electrically connected to the control device 21 is provided with an alarm 27 for alarming an abnormal combustion.

Based on the above configuration, the pressure detecting operation of the pressure detecting device 20 will be described first. When the heat exchanger 5 is heated by the combustion gas, the heat exchanger 5 contains a trace amount of impurities such as tar during liquefaction of petroleum contained in the gas as a fuel and adheres to the heat exchange surface of the fins 19 and the water pipe 18 over a long period of use. And
In addition, carbon generated from incomplete combustion due to unstable flame formation at the start and stop of combustion and the like is deposited as soot. In particular, the temperature of the fins 19 and the pipes 18 is lower than that of the heat exchanger of the hot air heater, and the amount of deposition is larger even with the same combustion apparatus.

The combustion gas 12 of the burner 15 receives the pressure of the blower 11 and passes through the narrow space between the fins 19 to heat the heat exchanger 5. If soot and the like adhere to the fins 19, the ventilation resistance increases.

[0014] Figure 2 shows a level DL to the horizontal axis clogging of the fin 19 progresses, the pressure difference Delta] p the pressure detecting device 20 along the vertical axis at level A when using initial cleaning detects the pressure difference Delta] p _s a small pressure difference Delta] p _s the fin clogging progresses gradually increases. When the level DL is the level B, the pressure difference Δp _j is the reference criterion of the pressure determiner 22, and further proceeds to the allowable level D, where the pressure difference Δp _m is a predetermined value.
Becomes If the operation is continued while being left in this state, as indicated by the broken line, the pressure difference Δp
Progresses more and more over time.

FIG. 3 shows the blowing characteristics of the blower 11, wherein the horizontal axis represents the blowing amount Q, the vertical axis represents the blowing pressure p _o , and at the level A, the operating point of the blowing amount Q _s and the pressing pressure p _os . The air blow at (A) is supplied to the burner 15. At the level A, the curve C is controlled in a range S indicated by the oblique line between the curve C and the curve a, corresponding to the proportional control of the fuel supply amount by the gas proportional valve 10. For example, when the pushing pressure is fixed to p _os , the minimum air volume Q _B is obtained for the curve a. That is, the blower 11 also has a capacity control function, have a margin still in blowing rate Q relative blowing rate Q _s in the level A, the curve C is set to be lower relative to the maximum capacity of the curve e.

When the use time elapses and clogging of the fins 19 progresses and the level A becomes the level B, the pressure detecting device 20
Detects the pressure difference Δp _j . The pushing pressure of the blower 11 rises to _{+ p oj = p os (Δp} j -Δp s),
When leaving the driving current I _F of the blower 11 in the same as in the level A, the burner 15 pushing pressure p _oj, air volume Q
The air of _j is supplied, and the insufficient airflow Δ
An imbalance of Q = Q _s −Q _j occurs. This imbalance causes emissions of harmful and harmful exhaust gases such as CO,
Acceleration of fin clogging due to a large amount of unburned carbon, causing abnormally high and unpleasant combustion noise accompanied by vibration, and furthermore, it is difficult to maintain the formation of combustion flame, causing many problems such as fire extinguishing. Become.

[0017] Therefore, the pressure determination unit 22 which receives the detection signal of the pressure detecting device 20, from the data shown in FIG. 3 the data storage unit 24 is stored, air volume Q _s in pushing pressure p _oj
The operating point (C) is read. Next, as shown in FIG. 3 is another memory data, a driving current I _s from the data of the drive current I _F corresponding to the level DL and outputs an instruction signal for changing the I _j. The driving unit 23 that has received the instruction signal transmits the driving current _Ij to the blower 11. Thus, burner 15
Even if the fins 19 are stuck at the level B, the same combustion as at the level A can be performed, and the occurrence of the above problem can be suppressed.

When the signal reaches level D after passing level B,
Pressing pressure p of the blower 11_mIs p _m= P_os+ (Δp_m
−Δp_s) And the air volume Q_sCan maintain the blast
The maximum capacity of the machine 11 and the maximum drive required to blow air at curve e
Current I_mIs supplied. Blower 11 responds to fin clogging
This level D is the upper limit. And the curve
Suitable for maximum combustion that can respond to C and curve e fin clogging
If the response range K is exceeded, the display 27 indicates that the usage limit is reached.
Display and prompt replacement of new equipment.

Even if the level exceeds level D, the water heater can be further operated in consideration of the time required for replacement of new equipment. However, if it exceeds the level D, it becomes impossible to blow air corresponding to the maximum supply of fuel. Then, for example, at the level E, the detection signal of the pressure detection device 20, the control device 21 the operating point of the curve e (E) is detected of the blower 11, stores the air volume Q _x according to the operating point (E) The data is read from the data, and the data storage unit 24 outputs a signal of the corresponding fuel supply amount based on the storage data of the fuel supply amount and the blown air amount Q within the capacity proportional control range stored in advance. That is, the fuel supply amount falls below the maximum value. Also in this case, the same problem as the operating point (B) that occurs when the fuel supply amount is left at the maximum value can be appropriately avoided.

As described above, by initially setting the blowing capacity of the blower 11 to be equal to or less than the maximum capacity, the heat exchanger 5 is closed by the deposition of soot or the like, and the burner 15 is closed.
Even if the ventilation resistance of the combustion gas 12 is increased, if the blowing capacity of the blower 11 is increased to the maximum capacity, the burner 15
The combustion efficiency eta _B can be maintained on the setting efficiency during initial use to the blower 11 becomes maximum capacity. Then, even if the heat exchange efficiency η _E of the heat exchanger 5 due to clogging of soot and the like is reduced, η =
The total heat absorption efficiency η, which is η _B × η _E , can be obtained at a high efficiency by maintaining at least the combustion efficiency η _B. Can provide combustion.

Further, when the blowing capacity of the blower 11 is maximized takes the combustion on the appropriate balance the fuel supply amount in response to the blowing amount on p _o -Q characteristics of the blower maximum possible blowing capacity By adjusting and maintaining good combustion, acceleration of the generation of soot and the like can be avoided, operation can be performed for a long time even if it is a little, and emission of dangerous exhaust gas accompanied with CO and the like can be suppressed.

It should be noted that the correction of the blown air amount by the pressure difference detection signal is not limited to the above-described maximum combustion, but can be similarly performed during proportional control combustion such as a curve b. In this embodiment, the maximum combustion is frequently used at the start of combustion or the like, so that the maximum combustion is described as an example that can be easily adjusted. However, the level D can be determined at another combustion. Also,
Storing the correction coefficient of the drive current I _F according to the change of DL levels, may also be to shorten the computation time required of the driving means 23, pressure p _o is passed through a heat exchanger 5 of the combustion gases 12 The same pressure difference Δp can be detected in the previous detection.

[0023]

As is clear from the description above, according to the present invention, the water heater according to the present invention, the exhaust clogging with carbon or the like of the unburned heat exchangers is detected by the pressure detector, and the detection signal from the data storage unit Combustion of fuel and air at an appropriate combustion ratio based on the hot water supply output instruction signal that provides good combustion equivalent to the initial stage of use, and maintains the same combustion efficiency as the initial stage of use even if the heat exchanger causes the exhaust blockage. Thereby, an energy saving effect can be exhibited.

[0024] Further, since the blower has a supply capability higher than the maximum hot water supply capability in the initial stage of use, the detection signal of the pressure detecting device does not allow the blower corresponding to the maximum supply fuel to operate.
Can be continued until the value increases, and the acceleration period of the generation of unburned carbon or the like due to incomplete combustion due to insufficient air can be extended to extend the service life.

Further, the detection signal of the pressure detecting device is supplied to the maximum.
When the air flow corresponding to the fuel becomes impossible and the air amount of the blower cannot be increased, the hot water supply output is suppressed below the hot water supply output instruction signal, and the maximum of the blower is adjusted in accordance with the appropriate combustion ratio in the data storage. Since combustion can be performed by reducing the amount of air due to the supply capacity and the amount of fuel supply corresponding to this amount of air, it is possible to avoid incomplete combustion of insufficient air and to prevent CO gas and the like that are dangerous to the human body even at the end of using the water heater. Generation can be suppressed and safe use performance can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a water heater according to the present invention.

FIG. 2 is a characteristic diagram of the blower.

FIG. 3 is a characteristic diagram of the pressure difference and the drive current.

FIG. 4 is a configuration diagram of a conventional water heater.

[Explanation of symbols]

 Reference Signs List 5 heat exchanger 10 gas proportional valve 11 blower 19 fin 20 pressure detector 23 drive means 24 data storage

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F23N 1/02 102 F23N 5/18 101 F23N 5/24 104

Claims (1)

(57) [Claims] 1. A heat exchanger which burns combustion air from a blower and fuel from a fuel control valve in a combustion chamber cut off from outside air, absorbs heat from the combustion gas, and outputs hot water. A pressure detecting device that detects a pressure difference of the combustion gas before and after passing through the heat exchanger as a ventilation resistance passing through the heat exchanger, and is adapted to the pressure difference and a hot water supply output instruction signal corresponding to a hot water supply load to maintain good combustion. A data storage device that stores an appropriate combustion ratio of fuel and air to be heated, and the heat exchanger has a supply capacity greater than the pressure difference in the initial stage of use and an air amount of an appropriate combustion ratio corresponding to the hot water supply output instruction signal, When the pressure difference has increased to a predetermined value due to use progress, a blower that supplies the same amount of air as in the initial use, a detection signal of a pressure detection device, and a proper combustion from a data storage corresponding to the hot water supply output instruction signal. Ratio of fuel supply The amount of a drive means for instructing output blower fuel control valve and air quantity, the drive means is impossible blast the pressure detecting device corresponding to the maximum fuel supply
Become instructs outputs the maximum supply capacity to a value to detect a blower, the fuel control valve water heater has a configuration reduced to a fuel supply amount becomes proper combustion ratio corresponds to the maximum supply capacity of the blower.