JP3859837B2 - Combustion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single-can two-water channel combustion apparatus in which a hot water supply channel and a bath retreat channel pass through a common heat exchanger.
[0002]
[Prior art]
Conventionally, in a so-called canned and two-channel combustion apparatus, when a bath reheating command is issued during hot water supply, the bath reheating is started by driving the circulation pump and flowing water through the bath reheating route. .
[0003]
Then, when a restocking command is issued during hot water supply and water flows into the bath retreat path, part of the heat used to heat the water flowing through the hot water retreat path is It will be used for heating the water flowing through Therefore, the amount of heat for heating the water flowing through the hot water supply path to a predetermined set temperature is insufficient, and the hot water supply temperature is lowered. At this time, for example, a hot water temperature thermistor detects a decrease in the hot water temperature, and feedback control based on the deviation between the hot water temperature and the set temperature is performed, but a temporary change in the hot water temperature occurs.
[0004]
The change in the hot water supply temperature is caused by the heat absorption of water in the bath retreating path, and the amount of heat absorption varies depending on, for example, the temperature of the water flowing in the bath retreating path and the circulation flow rate. That is, the heat absorption amount is small when the temperature of the water flowing through the bath chase path is high, and the heat absorption amount is large when the water temperature is low. Further, the heat absorption amount is large when the circulation flow rate of the water flowing through the bath chase path is large, and the heat absorption amount is small when the circulation flow rate is small.
[0005]
Thus, although the heat absorption amount of water in the bath retreating path varies depending on various combustion conditions as described above, the feedback amount of feedback control has conventionally been fixed proportional (P), integral (I), differential ( D) It was calculated | required using the constant (henceforth a PID constant).
[0006]
[Problems to be solved by the invention]
When the PID constant is a preset fixed value and feedback control is performed based on the deviation between the hot water supply temperature and the set temperature, if the heat absorption amount of the water in the bath retreat path is different, appropriate feedback control is performed. May not be done.
[0007]
That is, if the heat absorption amount of the water in the bath follow-up path is large, a sufficient amount of feedback heat is not supplied to the water in the hot water supply path, and it takes a relatively long time for the hot water supply temperature to return to the set temperature. Further, if the heat absorption amount is small, the feedback heat amount given to the water in the hot water supply passage is too large, and the hot water supply temperature may cause hunting.
[0008]
Thus, when the PID constant is a fixed value, the hot water supply temperature cannot be appropriately controlled when the heat absorption amount of the water in the bath retreating path changes.
[0009]
Therefore, an object of the present invention is to provide a combustion apparatus capable of stably controlling the hot water supply temperature even when the heat absorption amount of the water in the bath retreating path is different during simultaneous use of hot water supply and bath reheating. Is to provide.
[0010]
In order to achieve the above object, a first configuration of the present invention is a canned and two-water channel combustion apparatus in which a hot water supply channel and a bath retreat channel connected to a bathtub pass through a common heat exchanger. When reheating is performed at the same time, the heat exchange based on the proportional / integral / derivative constants set so that the larger the heat absorption amount of the water in the bath retreating path in the heat exchanger is, the larger the value is. It has a control means for obtaining the amount of heat supplied to the vessel.
[0011]
With this configuration, since the amount of heat corresponding to the amount of heat absorbed by the water in the bath follow-up path is supplied to the heat exchanger, the hot water supply temperature can be controlled more stably during simultaneous use.
[0012]
Further, a second configuration of the present invention is the above-described first configuration, wherein the control means converts the heat absorption amount into a circulation flow rate in the bath retreating channel and water in the bath retreating channel entering the heat exchanger. It is a one-can two-water channel combustion apparatus characterized by being determined by temperature .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to this embodiment.
[0014]
FIG. 1 is a schematic configuration diagram of a single can two-water channel combustion apparatus according to an embodiment of the present invention. In FIG. 1, a hot water supply path 10 and a bath reheating path 20 pass through a common heat exchanger 1. The heat exchanger 1 is heated by a burner 3, and fuel gas is supplied to the burner 3 from a gas supply pipe 4. The gas supply pipe 4 is provided with a gas solenoid valve 5 for opening and closing the gas supply pipe 4 and a gas proportional valve 6 for adjusting the gas supply amount.
[0015]
The hot water supply passage 10 is connected to the inlet side of the heat exchanger 1, connected to the water supply pipe 11 that functions as a water supply passage for supplying water to the heat exchanger 1, and the outlet side of the heat exchanger 1. A hot water pipe 12 through which hot water heated by the hot water is discharged is connected and guided to a desired place such as a hot water tap 16 of the kitchen.
[0016]
The water supply pipe 11 is provided with a flow sensor 13 for detecting the amount of water supply and a water supply temperature sensor 14 for detecting the water supply temperature. Further, the hot water supply pipe 12 is provided with a hot water supply temperature sensor 15 for detecting the hot water supply temperature.
[0017]
On the other hand, the bath reheating channel 20 supplies the water in the bathtub 22 to the heat exchanger 1 by operating the circulation pump 21 arranged there, and the hot water heated in the heat exchanger 1 is again in the bathtub 22. It constitutes a circulation path poured into the water.
[0018]
A bath water path 20 upstream of the heat exchanger 1 is provided with a bathtub water temperature sensor 23 that detects the water temperature in the bathtub 22. Further, a reheating temperature sensor 24 that detects the temperature of hot water discharged from the heat exchanger 1 is provided in the bath reheating channel 20 on the downstream side of the heat exchanger 1.
[0019]
Then, based on the temperature and flow rate detected from the various sensors and the set temperature set by the remote controller 31 or the like, the control unit 30 composed of a microcomputer or the like controls the gas proportional valve 6 and the circulation pump 21 and the like. To do.
[0020]
For example, when using a single hot water supply, when the hot water user opens the hot water tap 16, a water flow having a flow rate of a certain amount or more is generated in the water supply pipe 11. When the flow sensor 13 detects this water flow, the control unit 30 obtains a feedforward heat amount and a feedback heat amount necessary for hot water supply at a set temperature in response to a detection signal from the flow sensor 13, that is, a hot water supply request. The opening degree of the gas proportional valve 6 is controlled.
[0021]
When a hot water supply alone is used, a bath reheating switch (not shown) provided in the remote controller 31 or the like is turned on, and when a bath reheating request is issued, simultaneous use of hot water supply and bath reheating is started. When a bath reheating request is issued, the control unit 30 drives the circulation pump 21 to circulate the water in the bathtub 22 through the bath reheating channel 20.
[0022]
FIG. 2 is a view showing a cross section of the heat exchanger 1. As shown in FIG. 2, a bath retreat path 20 is provided on the side opposite to the burner side in contact with the hot water supply path 10 provided on the burner side. And the water in the bath chase path 20 is indirectly heated by using the hot water in the hot water supply path 10 in the heat exchanger 1 as a heat medium. Therefore, during simultaneous use, the amount of heat of the heated hot water in the hot water supply passage 10 is absorbed by the hot water in the bath follow-up passage 20, so that the hot water supply temperature decreases. That is, the number of hot water supply, which is the amount of heat obtained by the water in the hot water supply passage 10, decreases.
[0023]
FIG. 3 is a diagram showing the relationship between the number of hot water supply and the opening of the gas proportional valve 6. Line A in FIG. 3 represents the number of hot water supply corresponding to the opening of the gas proportional valve 6 when hot water is supplied alone. As the opening of the gas proportional valve 6 changes from the minimum opening (min) to the maximum opening (max), the number of hot water supply represented in the line A increases.
[0024]
When the hot water supply alone is used at the same time, the water in the bath follow-up path 20 absorbs heat from the hot water in the hot water supply path 10, so that the number of hot water supply is reduced even at the same opening degree. Further, the amount of decrease varies depending on the endothermic amount. Therefore, the number of hot water supply at the time of simultaneous use shifts downward from the position of the line A as shown by lines B1, B2, and B3 in FIG. Lines B1, B2, and B3 represent hot water supply numbers when the endothermic amount of water in the bath retreating path 20 is small, when the endothermic amount is medium, and when the endothermic amount is large.
[0025]
As described above, when the hot water supply number changes due to the absorption of water in the bath follow-up path 20, the control unit 30 performs feedback control based on the deviation between the hot water supply temperature and the set temperature. At this time, if the PID constant is a fixed value when obtaining the feedback heat quantity in the feedback control, the hot water supply temperature control may not be appropriately performed as described above.
[0026]
FIG. 4 shows a case where the PID constant is a fixed value corresponding to a predetermined heat absorption amount assumed in advance (in this embodiment, for example, an intermediate heat absorption amount corresponding to the line B2 in FIG. 3). It is a figure which shows the change of the hot water supply temperature in different heat absorption amount.
[0027]
FIG. 4A shows a change in hot water supply temperature when the endothermic amount of water in the bath follow-up path is near a predetermined endothermic amount (corresponding to line B2 in FIG. 3). According to Fig.4 (a), although hot water supply temperature falls temporarily by simultaneous use, it returns to preset temperature rapidly with an appropriate feedback amount.
[0028]
Furthermore, FIG.4 (b) shows the change of hot water supply temperature when the heat absorption amount of the water of a bath chase path is larger than predetermined | prescribed heat absorption amount (corresponding to line B3 in FIG. 3). When the hot water supply temperature is lowered by simultaneous use and feedback control is performed, the PID constant is set corresponding to the heat absorption amount of the line B2 smaller than that even though the heat absorption amount is large. Is small. That is, the change in the opening degree of the gas proportional valve 6 is small. Therefore, as shown in FIG. 4B, it takes a relatively long time for the hot water supply temperature to return to the set temperature.
[0029]
Furthermore, FIG.4 (c) shows the change of the hot water supply temperature when the heat absorption amount of the water of a bath chase path is smaller than predetermined | prescribed heat absorption amount (corresponding to line B1 of FIG. 3). When the hot water supply temperature is lowered due to simultaneous use and feedback control is performed, the PID constant is set corresponding to the heat absorption amount of the line B2 larger than that even though the heat absorption amount is small. Is big. Therefore, when the opening of the gas proportional valve 6 is opened in accordance with this feedback heat amount, the hot water supply temperature changes greatly as shown in FIG. 4C, and hunting occurs.
[0030]
Therefore, in the embodiment of the present invention, a PID constant corresponding to the amount of heat absorbed by the water in the bath retreat path is given. Specifically, for example, a table of a plurality of PID constants corresponding to the amount of absorbed heat is stored in the memory of the control unit 30 as shown in FIG. The PID constant may be obtained by calculation from a predetermined relational expression. And the control part 30 calculates | requires feedback calorie | heat amount by selecting the PID constant according to actual heat absorption.
[0031]
More specifically, as shown in FIG. 4B, when the heat absorption amount of the water in the bath retreating path 20 is large, a relatively large feedback heat amount is required. Therefore, as shown in FIG. 5, a large PID constant is selected and a large amount of feedback heat is supplied. Thereby, even if there is much heat absorption amount of the water in the bath chase path 20, since sufficient feedback calorie | heat amount is supplied to the water of the hot water supply path 10, it becomes possible to return hot water supply temperature to preset temperature quickly. That is, even when the amount of heat absorption is large, as shown by the dotted line in FIG. 4B, appropriate feedback control substantially the same as in FIG. 4A is performed.
[0032]
As shown in FIG. 4C, when the heat absorption amount of water in the bath retreating path 20 is small, the hot water supply temperature is in the hunting state as described above when a large feedback heat amount is supplied. Therefore, as shown in FIG. 5, a small PID constant is selected and a relatively small amount of feedback heat is supplied. Thereby, an appropriate amount of feedback heat is supplied to the water in the hot water supply passage 10, and the hot water supply temperature can quickly return to the set temperature without causing hunting. That is, even when the endothermic amount is small, as shown by the dotted line in FIG. 4C, the appropriate feedback control substantially the same as in FIG. 4A is performed.
[0033]
In the present embodiment, the amount of heat absorbed in the water in the bath follow-up path 20 is, for example, the circulation flow rate in the bath follow-up path 20 and the heat exchanger 1 as described in the above-described conventional technology. It is judged from the temperature of the water in the bath chase path 20 that enters. And this circulation flow volume can be calculated | required from the detected value of the water amount sensor arrange | positioned at the driving current applied to the circulation pump 21, or the reheating path 20 not shown in FIG. Moreover, the detected value of the bath water temperature sensor 23 is used for the water temperature of the bath chase path 20, for example.
[0034]
【The invention's effect】
According to the present invention, in a single can two-channel combustion apparatus, even when hot water supply and bath reheating are used at the same time, even if the heat absorption amount of water in the bath retreating path is different, Since the feedback calorie | heat amount supplied to the water of a hot water supply path is calculated | required based on the proportionality / integral / differential constant according to the heat absorption amount of water, the hot water supply temperature can be controlled stably.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a single-can two-water channel combustion apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a cross section of the heat exchanger 1;
FIG. 3 is a diagram showing the relationship between the number of hot water supply numbers and the opening degree of the gas proportional valve 6;
FIG. 4 is a diagram showing a change in hot water supply temperature at different endothermic amounts when the PID constant is a fixed value corresponding to a predetermined endothermic amount assumed in advance.
FIG. 5 is an example of a table of a plurality of PID constants according to an endothermic amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat exchanger 10 Hot water supply path 20 Bath retreating path 21 Circulation pump 23 Bathtub water temperature sensor 30 Control part 31 Remote control

Claims (2)

In the one-can two-water channel combustion apparatus in which the hot water supply channel and the bath retreat channel connected to the bathtub pass through a common heat exchanger,
When hot water supply and bath reheating are performed at the same time, based on the proportional / integral / derivative constants set so that the larger the heat absorption amount of the water in the bath retreating passage in the heat exchanger, the larger the value , A can-and-two-channel combustion apparatus having a control means for obtaining an amount of heat supplied to the heat exchanger. In claim 1,
The one-can / two-channel combustion apparatus according to claim 1 , wherein the control means determines the heat absorption amount based on a circulation flow rate in the bath retreating path and a temperature of water in the bath retreating path entering the heat exchanger .

Images