JP3061516B2 - Gas water heater - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas water heater such as an instantaneous gas water heater. 2. Description of the Related Art In a conventional gas water heater, as means for controlling the hot water supply temperature, for example, a means based on feedback control shown in FIGS. 3 and 4 or a feedback control shown in FIGS. 5 and 6 is used. There is a control in which feedforward control is added. The gas water heater of the feedback control shown in FIG. 3 includes a main burner 1 ′, a heat exchanger 4 ′, and a water inlet 6.
', Inner body 7', gas proportional valve 8 ', hot water supply temperature detecting thermistor 9' provided in water supply passage 10 ', controller 11
′, A remote controller (remote controller) 12 ′, and as shown in the flowchart of FIG.
When the hot water supply temperature is set at 2 ', the hot water supply temperature from the heat exchanger 4' is detected by the hot water supply temperature detecting thermistor 9 ', and the temperature is compared by the controller 11'. When the temperature is higher than the set temperature, the gas proportional valve 8 ' When the temperature is lower than the set temperature, the opening of the gas proportional valve 8 'is widened to increase the gas amount to supply hot water at the set temperature. A gas water heater that incorporates feedforward control in addition to the feedback control shown in FIG. 5 includes a sensor 13 'for detecting the amount of water provided in an inlet channel 6', a thermistor 14 'for detecting the temperature of incoming water, and It has the same configuration as that of FIG. 3 (the same parts have the same reference numerals),
As shown in the flowchart of FIG.
When the hot water supply temperature is set, the incoming water temperature to the heat exchanger 4 'is detected by the incoming water amount detecting sensor 13' and the incoming water temperature detecting thermistor 14 ', respectively, and the required gas amount is calculated by the controller 11' and the calculated gas amount is calculated. Is supplied to the main burner 1 ', and the hot water supply temperature is detected by the hot water supply temperature detecting thermistor 9'. The temperature is compared by the controller 11 '. When the temperature is higher than the set temperature, the opening of the gas proportional valve 8' is reduced. Reduce the amount of gas,
When the temperature is lower than the set temperature, hot water at the set temperature is supplied by increasing the opening of the gas proportional valve 8 'to increase the gas amount. [0004] For example, as disclosed in Japanese Patent Application Laid-Open No. 58-205043, the amount of gas supplied to a main burner is controlled (so-called feedback control) in accordance with the outlet temperature of a heat exchanger, so that hot water and cold water are controlled. Is mixed by an automixer to obtain a mixed hot water. The hot water mixing ratio is adjusted while detecting the mixed hot water temperature, and this is fed back to the heating of the main burner to control gas combustion. . [0005] Furthermore, Japanese Patent Application Laid-Open No. 58-217148 discloses a method in which high-temperature tapping and appropriate-temperature tapping can be performed selectively or simultaneously, and gas discharged to a burner is supplied. The supply amount is determined by calculating the temperature of the water supplied to the water heater, that is, the input water temperature, the supply water flow rate, and the set tap water temperature, and is adjusted by adjusting only the flow rate on the cold water side. Temperature control. [0008] The feedback control shown in FIGS. 3 and 4 is based on a gas proportional control based on the difference between the hot water supply temperature and the set temperature when the hot water supply amount is changed and the set temperature is changed. The amount of gas is increased or decreased by a valve. However, since the amount of heat held by the heat exchanger is present, even if the amount of gas is increased or decreased, it does not immediately appear as a change in hot water supply temperature. Therefore, when the amount of hot water is changed and the temperature of the hot water is changed (adjusted), it takes a long time to stabilize with a large temperature fluctuation, so that there is a disadvantage that the usability is extremely poor. Further, in the feedback control shown in FIGS. 5 and 6 in which feedforward control is added, the above-mentioned disadvantage is considerably solved, but the response delay is ultimately accompanied by the temperature correction by the feedback control, resulting in a delay in response. There was a disadvantage that hot water having a stable temperature could not always be obtained. According to Japanese Patent Application Laid-Open No. 58-205043, at the start of tapping, the tapping side temperature of the heat exchanger is controlled by feedback control, and the tapping side temperature causes a hunting phenomenon. If you try to prevent the hunting, you have to suppress the rise of the tapping temperature, there is a problem that it takes time until the expected tapping temperature is obtained, and also when mixing hot and cold water as described above Due to the heat capacity of the heat exchanger, the tapping temperature of the heat exchanger hunts and becomes unstable, so that the mixing control of the tap water becomes unstable and difficult, and it takes time until a stable tapping temperature is obtained. The problem also arises. Further, in Japanese Patent Application Laid-Open No. 58-217148, a large amount of water flows into the heat exchanger at the start of hot water supply so that a large amount of water flows into the heat exchanger, so that the hot water temperature rises poorly. Also, since the mixing ratio of the hot water and cold water is determined only by the flow rate on the cold water side, the change in the amount of hot water with respect to the change on the water side is small, and therefore, the change in the amount of water entering the heat exchanger in the feedforward control cannot be sufficiently obtained. However, there is a problem that a stable mixture ratio of hot and cold water cannot be obtained in a short time. It is an object of the present invention to provide a gas water heater in which not only a quick rise in tapping temperature can be obtained at the start of tapping but also tapping at a set temperature can be performed in a short time even when mixing tap water. [0010] In order to achieve the above object, a gas water heater according to the present invention is provided so that a hot water temperature higher than a set hot water temperature can be obtained on a hot water outlet side of a heat exchanger. Feedforward heating control means for controlling a gas supply amount flowing through the gas supply passage of the main burner based on an amount of incoming cold water and an incoming water temperature flowing through the water supply passage connected to the exchanger, and connected to the heat exchanger Hot water mixing means for mixing cold water with high-temperature hot water flowing in the hot water path, temperature detection means for the mixed hot water obtained by the hot water mixing means, and the mixed hot water temperature detected by the mixed hot water temperature detecting means become the set temperature. one and a cold water amount to be mixed into the hot water and hot water of the hot water flowing through the hot water passage as
Decrease or increase the other according to the increase or decrease of
And a hot and cold water mixing ratio control means for controlling the hot and cold water mixing ratio Te,
The hot and cold water mixing ratio controlled by the hot and cold water mixing ratio control means
Of water entering the heat exchanger due to changes in hot water volume
It is an Abstract that gas <br/> scan feed amount of the feed-forward heat control means by changing has to be changed. Since the gas water heater of the present invention has the above-described structure,
The feedforward heating control means controls the amount of water flowing through the water supply passage and the amount of gas supplied to the main burner in accordance with the temperature of the incoming water, so that high-temperature hot water at a predetermined temperature is quickly obtained at the outlet side (outflow passage side) of the heat exchanger. Can be In this case, the gas supply
Feedback control based on heat exchanger outlet temperature
Hunting at the outlet temperature of the heat exchanger
And stabilizes at a predetermined high temperature. When the temperature of the mixed hot water of the hot water and the cold water flowing through the hot water path is detected by the mixed hot water temperature detecting means, the high temperature hot water flowing through the hot water path and the hot water flowing through the hot water path are detected so as to approach the set temperature. The mixing ratio with the cold water mixed therewith is controlled by the hot and cold water mixing ratio control means. In this case, since the high-temperature hot water from the tapping water path maintains a stable temperature, the control of the mixing ratio is easy, and the temperature of the mixed hot water is stabilized at the set temperature. Further, in the control according to the hot and cold water mixing ratio control means, and a hot water mixed cold water amount of the mixed ratio of the high-temperature hot water and the hot water and cold water one
When one is increased, the other decreases by that amount and conversely decreases
Since when is is intended to increase by that amount, but increasing amount of the cold water hot water when to increase for example cold water
When decreasing the amount of cold water, and conversely, decreasing the amount of cold water, the amount of high-temperature hot water is also increased by the amount of the reduced amount of cold water . [0013] As a result the flow rate through the high-temperature hot water, i.e. heat exchanger through the hot water passage is increased or decreased change, increase or decrease changes in response to changes in the cold water quantity flowing through the rapidly water supply path, Fi
The gas supply amount of the gas supply path by the feedforward heating control means is adjusted. As a result, tapping temperature can be set quickly
As soon as the temperature is reached, hot water with a stable tapping temperature is obtained.
Will be. An embodiment of a gas water heater according to the present invention will be described below with reference to the drawings. In FIG. 1, A is the main burner 1
Automatic control device for controlling the gas supply amount according to the amount of incoming water and the temperature of incoming water for combustion. For example, a hydraulic automatic gas valve 3 provided in a gas passage 2 to a main burner 1 is connected to a heat exchanger 4. A water pressure responsive device having a structure in which the amount of gas supplied to the main burner 1 is automatically controlled in proportion to the amount of water supplied to the heat exchanger 4 in conjunction with the diaphragm 5 responsive to the incoming water pressure, and a diaphragm chamber 17
Temperature responsive device that automatically controls the relationship between the amount of passing water and the amount of gas supplied to the main burner 1 according to the incoming water temperature by a water temperature responsive valve 22 provided in a flowing water passage communicating the primary chamber 17a and the upstream side of the venturi section 23. The automatic control device A is installed in the water supply channel 6 on the upstream side of the heat exchanger 4 and controls the opening of the proportional valve according to the amount of incoming water and the temperature of incoming water, regardless of the set temperature of hot water. A constant-temperature hot water delivery unit is configured to enable delivery of high-temperature hot water at a constant temperature from the downstream side of the exchanger. The specific structure of the water pressure responsive device and the water temperature responsive device of the automatic control device A will be described.
A hydraulic automatic gas valve 3 is provided in a valve chamber 15 provided in a gas passage 2 to the main burner 1 so as to face a valve seat 16 thereof, and the hydraulic automatic gas valve 3 is stretched over a diaphragm chamber 17 provided in a water supply passage 6. The diaphragm 5 is connected to the secondary chamber 17b of the diaphragm 5 via a valve shaft 18, and the primary chamber 17a of the diaphragm 5 is connected to the venturi 23 via a passage 25 to the venturi 23 and a balance valve 19. A bypass passage 20 communicating with the downstream side is provided. Further, the automatic hydraulic gas valve 3 is urged in the closing direction by a spring 21 so that the automatic hydraulic gas valve 3 reduces the pressure of water entering the heat exchanger 4 via the diaphragm 5. By responding, the amount of gas supplied to the main burner 1 is automatically controlled in proportion to the amount of water entering the heat exchanger 4. Reference numeral 23 denotes a venturi section provided in the water supply passage 6 on the downstream side of the hydraulic pressure responsive device. The venturi 23 communicates with the secondary chamber 17b of the diaphragm chamber 17 to generate a differential pressure in accordance with the amount of water supply, thereby generating a differential pressure. The hydraulic automatic gas valve 3 is controlled via the. Reference numeral 24 denotes a gas introduction pipe, and reference numeral 2a denotes a gas nozzle. Further, the water temperature responsive device comprises a diaphragm chamber 1
7, a water temperature responsive valve 22 is inserted and installed in a flowing water passage communicating the primary chamber 17a with the upstream side of the venturi portion 23, and the water temperature responsive valve 22 supplies water to the main burner 1 according to the incoming water temperature. By automatically controlling the relationship between the gas amounts, the amount of gas supplied to the main burner 1 is corrected even for a change in the incoming water temperature, so that accurate control can be smoothly performed. B is a motor valve which mixes high-temperature hot water previously produced in the heat exchanger 4 with cold water which is branched from the water supply passage 6 and detects the mixed water temperature based on the mixing ratio. A water mixing apparatus (automixer) that automatically controls the hot water supply temperature to a set value is installed in the hot water supply path 30 on the downstream side of the heat exchanger 4 so that the mixing ratio between high-temperature hot water and cold water can be controlled without a response delay. And a mixing ratio control unit. The concrete structure of the hot water mixing apparatus B is a hot water side control valve 27 provided at one end of a valve shaft 26 at a constant interval.
And a mixing valve comprising a water-side control valve 28 are freely inserted into the mixing chamber 29 to move forward and backward. Also,
A water-side control valve 28 is provided on a water-side valve seat 33 provided at an outlet of a mixer water supply path 32 branched from a water supply path 6 and connected to a mixing chamber 29 so as to be able to approach and separate from each other. The other end of the valve shaft 26 is integrally connected to the motor shaft of the servo motor M, and the servo motor M is driven forward and reverse to a required angle, whereby the valve shaft (not shown) is engraved on the valve shaft 26. The hot water side control valve 27 and the water side control valve 28 are moved toward and away from the respective valve seats 31 and 33 so that the respective opening degrees can be changed and adjusted in directions opposite to each other. A hot water supply pipe 34 extending from the mixing chamber 29
Is provided with a thermistor 35 for detecting a hot water supply temperature, and the thermistor 35 is connected to a controller 36 to connect a hot water supply pipe 34.
The temperature of hot water flowing through the inside is detected and input to the controller 36, and the rotation of the servo motor M is controlled by a command from the controller 36 based on a signal from the thermistor 35. Further, the controller 36 can be operated by the remote controller (remote controller) 12. In FIG. 1, reference numeral 7 denotes an inner body. In the above configuration, an automatic control device A comprising a water pressure responsive device and a water temperature responsive device installed in the water inlet channel 6 on the upstream side of the heat exchanger 4, and the hot water supply channel 30 on the downstream side of the heat exchanger 4
When the hot water supply temperature is set by the remote controller 12 in step 101 as shown in the flowchart of FIG. 2 by the combination with the motor-driven hot / water mixing device B installed in the Irrespective of this, the main burner 1 is burned by automatically controlling the amount of water supplied to the heat exchanger 4 and the amount of supplied gas in accordance with the temperature of incoming water, and hot water of a constant high temperature is prepared in advance by the heat exchanger 4 in step 103. At 104, high-temperature hot water sent from the downstream side of the heat exchanger 4 is guided to the feed water mixing apparatus B via the hot water supply path 30 and mixed with cold water supplied from the water supply path 6 via the mixer water supply path 32. The hot water mixed at 29 is sent out from the hot water supply pipe 34. The hot water temperature flowing through the hot water pipe 34 is detected by the hot water temperature detecting thermistor 35 at step 105. When you enter the Controller 36,
In step 106, the controller 36 compares the hot water supply temperature with the set hot water supply temperature. When the hot water supply temperature is higher than the set hot water supply temperature, the hot water is reduced to increase cold water, and the hot water supply temperature is lower than the set hot water supply temperature. At this time, the hot water side control valve 27 and the water side control valve 28 of the hot and cold water mixing apparatus B are operated by driving the servo motor M in accordance with a command from the controller 36 so as to increase the amount of hot water and reduce the amount of cold water. Is automatically controlled such that the mixing ratio with
The hot water of the hot water supply temperature set at 7 is supplied from the hot water supply pipe 34. The amount of flowing water is sensed by the diaphragm 5 of the water supply passage 6 in conjunction with the increase or decrease in the flow rate of the high-temperature hot water flowing through the water heater 6, and the gas flowing through the gas passage 2 of the main burner 1 via the automatic hydraulic gas valve 3. The supply volume is changed to the expected volume. For example, when the flow rate of the high-temperature hot water flowing through the hot water supply path 30 increases, the flow rate of the hot water supply path 6 increases, and at the same time, the gas supply amount to the main burner 1 increases. As a result, gas heating according to the amount of cold water flowing through the water supply passage 6 is performed, and the hot water temperature of the high-temperature hot water flowing through the hot water supply passage 30 on the outlet side of the heat exchanger 4 is quickly achieved to the desired set temperature. Conversely, for example, when the flow rate of the high-temperature hot water flowing through the hot water supply passage 30 decreases, the amount of flowing water in the water supply passage 6 decreases, and at the same time, the gas supply amount to the main burner 1 decreases. As a result, gas heating corresponding to the amount of cold water flowing through the water supply passage 6 is also performed, and the temperature of the high-temperature hot water flowing through the hot water supply passage 30 on the outlet side of the heat exchanger 4 is quickly achieved to the desired set temperature. . Thus, according to the present invention, at the start of tapping, the tapping temperature of the tapping side of the heat exchanger 4 is quickly raised by feedforward control, and high-temperature tap water at the desired set temperature is quickly obtained. In this point, as in the conventional feedback control, the tapping temperature of the tapping side of the heat exchanger 4 causes a hunting phenomenon. In order to prevent the hunting, the tapping temperature rises slowly, and it takes time until the desired tapping temperature is obtained. Is eliminated. Also, as compared with the case where the mixing ratio of hot and cold water is changed only by the flow rate on the cold water side as shown in the above-mentioned Japanese Patent Application Laid-Open No. 58-217148, the present invention reduces the flow rate on the high-temperature hot water side. The rising of the tapping temperature is quick, and the desired tapping temperature can be obtained quickly. According to the present invention, when mixing hot and cold water,
The amount of flowing water flowing through the heat exchanger 4 changes quickly with respect to the valve operation of the hot and cold water mixing valves (the hot water side control valve 27 and the water side control valve 28). Change. This is because the amount of flowing water and the heating of the main burner 1 are controlled by feedforward control, so that the outlet temperature of the heat exchanger 4 quickly reaches the desired temperature, and the outlet temperature is It is stable without hunting. As a result, stable control of mixing high-temperature hot water and cold water becomes easy, and hot water can be stably discharged at the set temperature in a short time. Also in this regard, as in the case of the conventional feedback control, the tapping temperature becomes unstable due to the hunting effect due to the heat capacity of the heat exchanger, and the mixing control of the tapping water becomes difficult without stability, and a stable tapping temperature can be obtained. There is no problem that it takes a long time. Further, according to the present invention, the amount of hot water is inversely proportional to the change on the water side, as compared with the above-mentioned one disclosed in Japanese Patent Application Laid-Open No. 58-217148, in which the mixing ratio of hot water and hot water is determined only by the flow rate on the cold water side. It can be said that the present invention is also excellent in comparison with the point that the amount of incoming water in the feedforward control can be sufficiently changed due to the appropriate change, and a stable mixing ratio of hot and cold water can be obtained in a short time. The present invention is not limited to the above embodiment, and various design changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, the shaft valve 26 integrally provided with the hot water side control valve 27 and the water side control valve 28 of the hot water mixing apparatus B is connected to the servo motor M, and both control valves are driven by driving the servo motor M. Although the control valves 27 and 28 are operated, both control valves may be separately provided to individually control the increase / decrease of each control valve independently.・
This can also be achieved by a mechanical mechanism. In the above embodiment, the amount of cold water in the water supply passage 6 and the amount of gas in the main burner 1 are controlled in an interlocking manner by the automatic hydraulic pressure gas valve 3. A similar effect can be achieved even if a gas opening / closing control valve is proportionally controlled by a detection signal of the provision. As described above, according to the present invention, since the outlet hot water temperature of the heat exchanger quickly rises to a predetermined high temperature and stabilizes, the mixing control of the hot water and the cold water is performed. It becomes easy and the temperature of the mixed water becomes stable. In addition, the mixing ratio of hot water and cold water
If you increase one, the other will decrease by that amount,
The amount of water flowing through the heat exchanger quickly increases and decreases, and the gas supply amount is quickly controlled in a feed-forward manner.Accordingly, a stable tap water at a set temperature can be obtained in a short time. It is something that can be done. Therefore, this gas water heater is extremely convenient for consumers.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing an embodiment of a gas water heater according to the present invention. FIG. 2 is a flowchart of the operation state. FIG. 3 is a schematic configuration diagram of a conventional example. FIG. 4 is a flowchart of the operation state. FIG. 5 is a schematic configuration diagram of a different conventional example. FIG. 6 is a flowchart of the operation state. DESCRIPTION OF SYMBOLS A Automatic control device 1 Main burner 3 Automatic water pressure gas valve 4 Heat exchanger 5 Diaphragm 6 Water supply channel 13 Hot water mixing device 22 Water temperature responsive valve 29 Mixing chamber 30 Water supply channel 32 Mixer water supply channel 34 Hot water supply pipe 35 Hot water supply Temperature detection thermistor 36 Controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F24H 1/10 F24H 9/20

Claims (1)

(57) [Claims] The gas supply path of the main burner is changed based on the water input amount and the cold water flowing through the water supply path connected to the heat exchanger so that a hot water temperature higher than the hot water set temperature is obtained on the hot water outlet side of the heat exchanger. Feed-forward heating control means for controlling the amount of flowing gas, hot-water mixing means for mixing cold water with high-temperature hot water flowing through a tapping path connected to the heat exchanger, and temperature of the mixed hot water obtained by the hot-water mixing means Detecting means, and increasing or decreasing one of an amount of hot water flowing through the tapping channel and an amount of cold water mixed with the high-temperature water so that the temperature of the mixed water detected by the mixed-water temperature detecting means becomes a set temperature. Fit
Allowed to reduce or increase the other and a hot and cold water mixing ratio control means for controlling the hot and cold water mixing ratio, hot water changes the hot water in the hot and cold water mixing ratio controlled by the hot and cold water mixing ratio control means
Accordingly, the amount of water supplied to the heat exchanger is changed to change the gas supply amount of the feedforward heating control means .
Gas water heaters, characterized in that there was Unishi.