JPH11257739A - Gas hot water supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress waste of fuel gas while heat insulating the retaining water as required. SOLUTION: A heat exchanger 13 is disposed on the channel between a water supply port 11 and a hot water delivery port 12 and water in the heat exchanger 13 is heated by means of a gas burner 21. When water is not flowing through the channel, temperature sensors 32-34 detect the temperature of retaining water and when it drops below a reheating temperature, a heat insulation control section 30a fires the gas burner 21 for a specified time to raise the temperature of retaining water. If the temperature of retaining water detected by the temperature sensor 32-34 exceeds an upper limit heat insulation temperature, a prohibiting section 30b prohibits firing of the gas burner 21 to interrupt heat insulation of retaining water. Since the gas burner 21 is not fired when the temperature of retaining water exceeds the upper limit and heat insulation is not required, waste of fuel gas is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a gas water heater.

[0002]

2. Description of the Related Art In general, a gas water heater used for applications in which hot water comes into contact with a hand immediately after a hot water tap is opened, such as dishwashing, a washing surface, or a shower, does not cause a feeling of cold water to a person immediately after the hot water supply is started. Is desired. In order to satisfy this type of demand, a technique has been proposed for keeping the water held in the gas water heater (hereinafter referred to as "held water") warm when the hot water is not being supplied. This is so that the temperature of the water retained in the gas water heater is maintained at a predetermined temperature or higher even when hot water is not being supplied.
When the temperature of the retained water drops to the reheating temperature, the gas burner is ignited to keep the temperature. With this technology,
Since the temperature of the water retained in the gas water heater can be kept relatively high, the time until the temperature of the hot water discharged from the hot water tap reaches the set temperature after starting the hot water supply from the hot water tap is relatively short. be able to.

[0003]

By the way, the above-mentioned reheating temperature is set to a temperature lower than the set temperature set as the temperature of hot water to be supplied by a specified temperature difference. Therefore, in order to keep the temperature, it is necessary to perform an arithmetic process for obtaining the reheating temperature with respect to the set temperature. Further, it is necessary to determine whether the temperature has decreased to the reheating temperature, and to perform a process for intermittently igniting the gas burner 21. In addition, the load of the process for keeping the heat is relatively large.

[0004] Such a heat retention operation is performed based on the temperature difference between the set temperature and the outside temperature or the temperature of the retained water. Therefore, even when the temperature of the outside temperature or the retained water is relatively high as in summer, The gas burner will be ignited intermittently. However, when the water temperature is relatively high, there is no cold feeling immediately after the start of hot water supply even if the temperature is not kept, and the time required for the temperature of the hot water to reach the set temperature from the start of hot water supply is short. Often. In the above-described conventional configuration, there is a problem that the fuel gas is wastefully consumed because the temperature is kept even when the heat retention is not necessary, and that the load on the control circuit is increased, resulting in wasteful power consumption.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas water heater in which the holding water is kept warm when necessary, while suppressing unnecessary consumption of fuel gas and electric power. It is in.

[0006]

SUMMARY OF THE INVENTION The present invention provides a heat exchanger provided on a flow path formed between a water inlet through which water flows in and a hot water outlet through which water is discharged, and water in the heat exchanger. A gas burner to be heated, a temperature sensor that detects at least one of an outside air temperature and a water temperature, a flow sensor that detects water flowing into the flow channel, and that water flowing into the flow channel is stopped. When the temperature of the water held in the flow path decreases to a reheating temperature lower than the set temperature by a specified temperature difference while being detected by the flow rate sensor, the water held in the flow path is kept warm. As described above, the temperature control device includes a heat retention control means for intermittently igniting the gas burner to perform a heat retention operation, and a heat retention inhibition means for prohibiting the heat retention operation by the heat retention control means when the temperature detected by the temperature sensor exceeds the heat retention upper limit temperature. . According to this configuration, if the temperature of the retained water drops to the reheating temperature while the passage of water in the flow path is stopped, the gas burner is intermittently ignited to keep the retained water in the flow path warm. It is possible to prevent a feeling of cold water immediately after the start of hot water supply under conditions where the outside air temperature is low and the water temperature is low as in winter. In addition, when the temperature detected by the temperature sensor is equal to or higher than the upper limit temperature, the heat-retaining operation is prohibited by the heat-retaining control means. The heat keeping control means does not operate, and wasteful consumption of fuel gas is prevented. Further, a load for performing the process as the heat retention control unit is not applied, and unnecessary power consumption does not occur. Here, the heat retention upper limit temperature may be determined with reference to the outside air temperature in summer or the temperature of the retained water in summer.

[0007]

FIG. 1 shows a schematic configuration of a 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 water flows in from outside and a water supply port 12 for discharging water.
A heat exchanger 13 is provided on the flow path between the heat exchanger 13 and the heat exchanger 13. The heat exchanger 13 is housed in the hot water supply combustion chamber 41 together with the gas burner 21, and water passing through the heat exchanger 13 is heated by the gas burner 21. A flow sensor 31 is provided on a 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. The temperature of the water flowing from the water supply port 11 and passing through the flow rate sensor 31 is detected by the temperature sensor 32. A temperature sensor 34 that is heated by the heat exchanger 13 and detects the temperature of hot water discharged from the hot water outlet 12 is disposed near the hot water outlet 12,
Further, a temperature sensor 33 for detecting the temperature of the hot water discharged from the heat exchanger 13 is provided. A flow control valve 35 is provided on the flow path between the heat exchanger 13 and the tap 12 and near the tap 12. A gas burner 21 is connected to a gas connection port 22 through an original gas valve 23 which is an electromagnetic valve.
And fuel gas is supplied through the gas proportional valve 24.

Incidentally, the original gas valve 23 and the gas proportional valve 2
4. The flow sensor 31, the temperature sensors 32 to 34, and the flow control valve 35 are connected to a control circuit 30 including a microcomputer as shown in FIG. The control circuit 30 is based on the inputs from the flow sensor 31 and the temperature sensors 32-34.
According to the procedure shown in FIG. 2, the source gas valve 23, the gas proportional valve 24, and the flow control valve 35 are controlled. That is, when a hot water tap (not shown) connected through the tap hole 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 switched off. Open and ignite the gas burner 21 (S2). Gas burner 21
Although the ignition means is not shown, a means for continuously generating a spark and igniting is used, and a means for stopping the spark when the ignition of the gas burner 21 is detected by a flame sensor (not shown) is used. ing. This type of ignition means is well known. After the gas burner 21 is ignited, the gas proportional valve 24 and the flow control valve 3 are controlled so that the tapping temperature detected by the temperature sensor 33 becomes a preset temperature.
5 is used to adjust the tapping temperature (S3, S4).

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 extinguishes, the temperature of the retained water in the flow passage drops significantly in winter. Therefore, in a state where the passage of water in the flow path is not detected, the heat keeping operation is performed by the heat keeping control section (heat keeping control means) 30 a provided in the control circuit 30. In the warming operation, when the temperature detected by the temperature sensors 32 to 34 decreases to a preset reheating temperature (S7), the gas burner 21 is intermittently ignited for a predetermined time (S8), and the retained water gives a feeling of cold water. Moderate temperature (that is, water temperature that feels very cold when touched)
This is a process of raising the temperature of the retained water before the temperature of the water decreases. 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 from the set temperature. Here, since the heat capacity of the flow path and the retained water is relatively large, the gas burner 21
, The temperature detected by the temperature sensors 32 to 34 does not immediately rise. However, since there is a substantially constant relationship between the amount of combustion of the gas burner 21 and the rise in the temperature of the retained water, one ignition time of the gas burner 21 is set to such an extent that a predetermined rise in temperature is obtained. Further, it is not necessary to use all of the temperature sensors 32 to 34 for the temperature detection at the time of the warming operation, and only one of the temperature sensors 32 to 34 may be used.

By the way, even if the gas burner 21 extinguishes,
In summer, the temperature of the water retained in the channel does not drop much. Even if the temperature drops, the water temperature is relatively high and the water temperature rises immediately after the start of hot water supply, so that a feeling of cold water does not occur. As described above, in most cases in summer, the warm-up operation is unnecessary. Therefore, when the temperature detected by the outside air or the retained water by the temperature sensors 32 to 34 reaches the preset upper limit temperature (S6), the operation of the heat retention control unit 30a is prohibited by the heat retention prohibition unit (heat retention prohibition means) 30b. (The warming operation in steps S7 and S8 is not performed). In short, the ignition of the gas burner 21 for keeping the temperature is prohibited, and the keeping operation is not performed. In addition, since the operation of the heat retention control unit 30a is prohibited, temperature detection as the heat retention control unit 30a is unnecessary, and the gas burner 2
There is no need to manage the ignition / extinguishing of (1). That is, fuel gas consumption is reduced, and power consumption is also reduced.
Further, in the present embodiment, the heat retention control unit 30a and the heat retention prohibition unit 30b are provided in the control circuit 30 constituted by a microcomputer. However, since the heat retention prohibition unit 30b is basically a process of only temperature detection, The load is small as compared with the processing of the control unit 30a, and the load of the processing is reduced by inhibiting the warming operation as compared with the case where the warming operation is performed.

[0011]

According to the present invention, there is provided a temperature sensor for detecting at least one of an outside air temperature and a water temperature, and a flow passage formed between a water supply port through which water flows in and a hot water outlet through which water is discharged. A flow rate sensor for detecting water, and a temperature of water held in the flow path while the flow sensor detects that the flow of water into the flow path is stopped is defined with respect to a set temperature. When the reheating temperature drops to a lower reheating temperature by the temperature difference, the gas burner is intermittently ignited so as to keep the water retained in the flow path, and a heat retention control means for performing a heat retention operation, and the temperature detected by the temperature sensor is kept warm. A heat retention inhibiting means for inhibiting the heat retention operation by the heat retention control means when the temperature exceeds the upper limit temperature. According to this configuration, the temperature of the retained water is reheated while the passage of water in the flow path is stopped. When the temperature drops, the gas burner is turned on intermittently. Was held water in the flow path by insulation, it is possible to prevent cold water sensation immediately after the start hot water in winter outside air temperature is low temperature is low condition as. In addition, when the temperature detected by the temperature sensor is equal to or higher than the upper limit temperature, the heat-retaining operation is prohibited by the heat-retaining control means. Insulation control means does not work,
There is an advantage that wasteful consumption of fuel gas is prevented, no load is applied for performing processing as the heat retention control means, and wasteful power consumption does not occur.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) is a schematic configuration diagram, and (b) 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 Outlet 13 Heat exchanger 21 Gas burner 30 Control circuit 30a Heat retention control part 30b Heat retention prohibition part 31 Flow rate sensor 32-34 Temperature sensor

Claims (1)

[Claims] 1. A heat exchanger provided on a flow path formed between a water supply port into which water flows in and a hot water outlet for discharging water, a gas burner for heating water in the heat exchanger, and an outside air temperature. A temperature sensor that detects at least one of a water temperature, a flow sensor that detects water flowing into the flow channel, and a flow sensor that detects that the flow of water into the flow channel is stopped. When the temperature of the water held in the flow path drops to the reheating temperature, which is lower than the set temperature by the specified temperature difference, the gas burner is intermittently ignited to keep the water held in the flow path warm A gas water heater comprising: a heat-retaining control means for performing a heat-retaining operation in such a manner; and a heat-retaining prohibiting means for prohibiting the heat-retaining operation by the heat-retaining control means when a temperature detected by the temperature sensor becomes equal to or higher than a heat-retaining upper limit temperature.