JP3869547B2 - Gas water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas water heater.
[0002]
[Prior art]
Recently, the number of gas water heaters installed outdoors has increased, and in order to check the operation of the gas burner during maintenance or during a trial run after construction, the person who opens and closes the water heater indoors and the ignition and extinguishing of the gas burner outdoors. The inspection work is troublesome because two people are required to monitor the condition.
[0003]
On the other hand, in gas water heaters that are used for purposes such as dishwashing, washing, and showering, where hot water comes into contact immediately after opening the hot water tap, hot water is supplied to prevent people from feeling cold immediately after the start of hot water supply. There has been proposed a technique for keeping warm water (hereinafter referred to as retained water) held in a gas water heater when there is not. This is to keep the gas burner ignited when the temperature of the retained water falls to the reheat temperature so that the temperature of the retained water in the gas water heater is maintained at a predetermined temperature or higher even when hot water is not being supplied. is there. If such a heat retaining operation is performed, the temperature of the retained water in the gas water heater can be kept relatively high, so the temperature of the hot water discharged from the hot water tap after the hot water supply from the hot water tap is started becomes the set temperature. The time to reach is relatively short. Further, it is considered that even one person can check the ignition / extinguishing state of the gas burner because the gas burner is intermittently ignited while water is not passed during the heat insulation operation.
[0004]
[Problems to be solved by the invention]
However, waiting for the gas burner to ignite intermittently during the heat insulation operation does not know when the gas burner is ignited and when it is extinguished, and it may take a long time to check the gas burner.
This invention is made | formed in view of the said reason, The objective is to provide the gas water heater which enabled it to check a gas burner easily, even when installed outdoors.
[0005]
[Means for Solving the Problems]
The invention of claim 1 is a heat exchanger provided on a flow path formed between a water supply port through which water flows in and a hot water outlet from which water is discharged, a gas burner for heating water in the heat exchanger, A flow rate sensor for detecting water flow into the flow path, an ignition control means for igniting the gas burner when the flow rate per unit time detected by the flow rate sensor exceeds a predetermined value, and a housing for housing at least the heat exchanger and the gas burner And a test operation unit that is manually operated to instruct ignition / extinguishing of the gas burner when the flow rate per unit time that is provided in the housing and detected by the flow rate sensor is less than the predetermined value, and the provision on the flow path A temperature sensor that detects the water temperature at a location, and the temperature detected by the temperature sensor is equal to or higher than the superheat temperature set lower than the temperature at which the water in the heat exchanger boils when the gas burner is ignited. It is intended to prohibit the ignition of the gas burner according to sometimes test operation of the manual operation. According to this configuration, even if the housing is installed outdoors, the gas burner can be ignited or extinguished by manually operating the test operation section. Confirmation can be easily performed by one person. Further, when the heat exchanger is overheated by operating the test operation unit, safety is prioritized and the ignition of the gas burner is prohibited.
[0007]
The invention according to claim 2 is the invention according to claim 1, wherein the gas burner is intermittently ignited and held in the flow path when the flow rate per unit time detected by the flow rate sensor is less than the predetermined value. A heat retention control means capable of performing a heat retention operation for retaining water is provided. According to this configuration, since it has a function to perform a heat insulation operation, the time until the hot water temperature rises after starting the hot water from the hot water tap connected to the hot water outlet is short, and hot water is used without causing a feeling of cold water. can do. Further, since the gas burner can be ignited at any time by operating the test operation unit without waiting for the intermittent ignition of the gas burner during the heat insulation operation, the operation check of the gas burner can be performed in a short time.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic configuration of the gas water heater. As shown in FIG. 1A, the gas water heater shown as the present embodiment includes a water supply port 11 into which city water flows and a hot water outlet 12 from which water is discharged, and includes a water supply port 11 and a hot water outlet 12. A heat exchanger 13 is provided on the flow path therebetween. The heat exchanger 13 is housed in the hot water supply combustion chamber 41 together with the gas burner 21, and the water passing through the heat exchanger 13 is heated by the gas burner 21. A flow sensor 31 is provided on the flow path from the water supply port 11 to the heat exchanger 13, and the flow sensor 31 detects whether water is flowing through the flow path. Further, the temperature sensor 32 detects the temperature of the water that has flowed from the water supply port 11 and passed through the flow rate sensor 31. A temperature sensor 34 that detects the temperature of hot water that is heated by the heat exchanger 13 and discharged from the hot water outlet 12 is disposed in the vicinity of the hot water outlet 12, and further detects the temperature of hot water that is discharged from the heat exchanger 13. A temperature sensor 33 is provided. In addition, a flow rate adjustment valve 35 is provided on the flow path between the heat exchanger 13 and the outlet 12 and in the vicinity of the outlet 12. Fuel gas is supplied to the gas burner 21 from the gas connection port 22 through the original gas valve 23 and the gas proportional valve 24 which are electromagnetic valves. A test switch (test operation unit) 36 is provided in a housing (not shown) in which these members are stored. The test switch 36 instructs ignition / extinguishing of the gas burner 21 during manual operation, and also instructs opening and closing of the original gas valve 23 and the gas proportional valve 24.
[0009]
By the way, the original gas valve 23, the gas proportional valve 24, the flow sensor 31, the temperature sensors 32 to 34, the flow control valve 35, and the test switch 36 are connected to a control circuit 30 composed of a microcomputer as shown in FIG. ing. The control circuit 30 includes an ignition means (not shown) for igniting the gas burner 21 according to the procedure shown in FIG. 2 based on the inputs from the flow sensor 31, the temperature sensors 32 to 34, and the test switch 36, the original gas valve 23, The gas proportional valve 24 and the flow rate adjusting valve 35 are controlled.
[0010]
That is, when a hot water tap (not shown) connected through the tap 12 is opened and the flow sensor 31 detects that water is flowing in the flow path (S1), the original gas valve 23 and the gas proportional valve 24 are turned on. Open and ignite the gas burner 21 (S2). Although the ignition means of the gas burner 21 is not shown, the ignition means that continuously generates sparks to ignite is used, and when the ignition of the gas burner 21 is detected by a flame sensor (not shown), the spark stops. Is used. This type of ignition means is well known. After ignition of the gas burner 21, the hot water temperature is adjusted by using the gas proportional valve 24 and the flow rate adjusting valve 35 so that the hot water temperature detected by the temperature sensor 33 becomes a preset temperature (S3, S4).
[0011]
On the other hand, when water flow in the flow path is no longer detected by the flow sensor 31 (S1), the original gas valve 23 and the gas proportional valve 24 are closed and the gas burner 21 is extinguished (S5). When the gas burner 21 is extinguished, the temperature of the retained water in the flow path generally decreases. At this time, if the test switch 36 is not operated (S6), the heat insulation operation is started by the heat insulation control unit (heat insulation control means) 30a provided in the control circuit 30. In the heat insulation operation, when the temperature detected by the temperature sensors 32 to 34 is lowered to a preset reheating temperature (S7), the gas burner 21 is ignited intermittently for a certain period of time (S8), and the retained water gives a cold water feeling. The temperature of the retained water is raised before it drops to a certain temperature (that is, a water temperature that feels very cold when touched). The reheating temperature is set to a temperature lower by a predetermined temperature than the set temperature set as the tapping temperature. In short, the reheating temperature is set to have a fixed temperature difference with respect to the set temperature. Here, since the heat capacities of the flow path and the retained water are relatively large, even if the gas burner 21 is ignited, the temperature detected by the temperature sensors 32 to 34 does not rise immediately. However, since there is a substantially constant relationship between the combustion amount of the gas burner 21 and the temperature rise of the retained water, one ignition time of the gas burner 21 is set to such an extent that a predetermined temperature rise can be obtained. Moreover, it is not necessary to use all the temperature sensors 32 to 34 for temperature detection during the heat insulation operation, and only one of the temperature sensors 32 to 34 may be used.
[0012]
On the other hand, when the flow rate detected by the flow sensor 31 is less than a predetermined value and the gas burner 21 is extinguished (S1, S5), when the test switch 36 is operated (S6), the gas burner 21 is ignited. (S9). The test switch 36 is a push button switch, and the gas burner 21 is ignited during the push operation. Here, a configuration in which the gas burner 21 is ignited for a certain time after the pressing operation may be employed, or a configuration in which the gas burner 21 is extinguished by a second pressing operation after the gas burner 21 is ignited by the pressing operation may be employed. Even when the test switch 36 is pushed, when the gas burner 21 is ignited and boiling occurs in the heat exchanger 13 (determined by detecting the water temperature on the flow path with any of the temperature sensors 32 to 34). Even if the test switch 34 is operated, the gas burner 21 is not ignited (S10).
[0013]
As described above, by providing the test switch 36, if the test switch 36 is manually operated at the time of maintenance or during a test run immediately after the construction, the ignition of the gas burner 21 at the time of hot water or the intermittent ignition of the gas burner 21 at the time of the heat insulation operation. In addition, the gas burner 21 can be ignited separately, and the inspection work of the gas burner 21 is facilitated.
[0014]
【The invention's effect】
The invention of claim 1 is a heat exchanger provided on a flow path formed between a water supply port through which water flows in and a hot water outlet from which water is discharged, a gas burner for heating water in the heat exchanger, A flow rate sensor for detecting water flow into the flow path, an ignition control means for igniting the gas burner when the flow rate per unit time detected by the flow rate sensor exceeds a predetermined value, and a housing for housing at least the heat exchanger and the gas burner And a test operation unit that is manually operated to instruct ignition / extinguishing of the gas burner when the flow rate per unit time that is provided in the housing and detected by the flow rate sensor is less than the predetermined value, and the provision on the flow path A temperature sensor that detects the water temperature at a location, and the temperature detected by the temperature sensor is equal to or higher than the superheat temperature set lower than the temperature at which the water in the heat exchanger boils when the gas burner is ignited. Sometimes is intended to prohibit the ignition of the gas burner by the test operation of the manual operation, since the housing or can extinguish or ignite the gas burner if the test operating unit manually even if installed outdoors, There is an advantage that the operation of the gas burner can be easily confirmed by one person at the time of maintenance or trial operation after construction. Further, when the heat exchanger is overheated by operating the test operation unit, the safety is prioritized and the ignition of the gas burner is prohibited, and there is an advantage that the safety is enhanced.
[0016]
As in the invention of claim 2 , when the flow rate per unit time detected by the flow rate sensor is less than the predetermined value, the gas burner is intermittently ignited to keep the water held in the flow path warm. A device equipped with a heat retention control means that can be operated has a function of performing a heat retention operation, so that the time until the hot water temperature rises after the start of the hot water supply from the hot water tap connected to the hot water outlet is short, and a feeling of cold water is almost generated. There is an advantage that hot water can be used without causing it to occur.
[Brief description of the drawings]
1A and 1B show an embodiment of the present invention, in which FIG. 1A is a configuration diagram and FIG. 1B is a block diagram around a control circuit;
FIG. 2 is an operation explanatory view of the above.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Water supply port 12 Hot water outlet 13 Heat exchanger 21 Gas burner 30 Control circuit 30a Thermal insulation control part 31 Flow rate sensor 32-34 Temperature sensor 36 Test switch

Claims (2)

A heat exchanger provided on a flow path formed between a water supply port through which water flows in and a hot water outlet from which water is discharged, a gas burner for heating water in the heat exchanger, and water flow into the flow channel A flow rate sensor for detecting gas, an ignition control means for igniting the gas burner when the flow rate per unit time detected by the flow rate sensor exceeds a predetermined value, a housing for housing at least the heat exchanger and the gas burner, and a housing. A test operation unit that is manually operated to instruct ignition / extinguishing of the gas burner when the flow rate per unit time detected by the flow sensor is less than the predetermined value , and a temperature at which the water temperature is detected at a specified location on the flow path When the temperature detected by the temperature sensor is equal to or higher than the superheat temperature set lower than the temperature at which the water in the heat exchanger boils when the gas burner is ignited, test operation is performed. Gas water heater and inhibits the ignition of the gas burner manual operation. A heat retention control means capable of performing a heat retaining operation for intermittently igniting the gas burner to keep the water held in the flow path when the flow rate per unit time detected by the flow sensor is less than the predetermined value is provided. The gas water heater according to claim 1 .

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