JPH11257746A - Gas hot-water supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of water hammering phenomenon by providing a pressure relief valve in a channel where a heat exchanger is included being formed between a water-supply port and a water-outgoing port and opening the pressure relief valve when a pressure sensor detects a pressure that is equal to or more than a prescribed value for causing the water hammering phenomenon. SOLUTION: When a hot-water supply plug connected to a hot-water-outgoing port 12 is opened and a flow-rate sensor 31 detects that water flows in the channel, a source gas valve 23 and a gas proportional valve 24 are opened and a gas burner 21 is ignited, and then hot water heated by a heat exchanger 13 is supplied. When the hot-water-supply plug is closed in this state and the flow-rate sensor 31 no longer detects the water passage in the channel, the main gas valve 23 and the gas proportional valve 24 are closed and the gas burner 21 is extinguished. At this time, a pressure detected by a pressure sensor 36 is compared with a prescribed value that is set higher to the extent so that water hammering phenomenon occurs, the pressure relieve valve 37 is opened by a water hammering suppression part 30b of a control circuit when a detection pressure is equal to or more than a prescribed value, thus preventing the pressure in the channel from increasing abnormally.

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, in a gas water heater, tapping and stopping are repeated, and a water hammer phenomenon may occur when stopping from tapping. The water hammer phenomenon is more likely to occur as the water pressure is higher. When the water hammer phenomenon occurs, the internal flow path receives a strong impact and vibrates, and such vibration may cause a failure.

Since the water hammer phenomenon occurs when the flow in the flow channel suddenly stops, the water hammer phenomenon is reduced by giving a time delay from when the hot water tap is closed to when the flow in the flow channel stops. It is thought that. For example, a valve called a water hammer buffer valve is provided at a tap for discharging hot water, and while the hot water tap is closed, the water pressure is relieved so that a sudden rise in water pressure near the hot water tap does not act on the gas water heater. It is thought to close.

On the other hand, in a gas water heater used for applications in which hot water discharged from a hot water tap is directly applied to a body, such as a dishwasher, a washing surface, and a shower, a hot water supply is not required to cause a feeling of cold water to a person immediately after starting hot water supply. There has been proposed a technique for keeping water held in a gas water heater (hereinafter, referred to as "held water") warm when not in use. This is to maintain the temperature by igniting the gas burner when the temperature of the water drops to the reheating temperature so that the temperature of the water held in the gas water heater can be maintained at or above the predetermined temperature even while hot water is not being supplied. is there. By performing such a heat retaining operation, the temperature of the water retained in the gas water heater can be kept relatively high, so that the temperature of the hot water discharged from the hot water tap after starting the hot water supply from the hot water tap reaches the set temperature. The time to reach is relatively short.

[0005]

However, since the water hammer buffer valve mechanically relieves the water pressure using a spring or the like, the range of pressure at which water hammer can be prevented is relatively narrow, and In some cases, the shooting phenomenon cannot be sufficiently suppressed. In particular, in a gas water heater performing a warming operation, the gas burner is ignited in a state where water is not passed during the warming operation, so that the pressure in the flow passage tends to increase. Since the water hammer damping valve is installed outside the device, extra space may be required or may not be installed.

[0006] 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 water pressure is controlled so as to mitigate a water hammer phenomenon.

[0007]

According to the first aspect of the present invention, there is provided 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. A gas burner for heating water, a flow sensor for detecting water flow into the flow path, an ignition control means for igniting the gas burner when a flow rate per unit time detected by the flow sensor becomes a predetermined value or more, A pressure sensor disposed on the flow path and detecting a water pressure in the flow path, a pressure relief valve for releasing the pressure in the flow path when the pressure sensor is opened, and a pressure detected by the pressure sensor is a specified value that is high enough to cause a water hammer phenomenon. A water hammer suppressing means for opening the pressure relief valve at one time to mitigate the water hammer phenomenon. According to this configuration, the pressure in the flow path is detected by the pressure sensor, and when the output of the pressure sensor becomes equal to or more than the specified value, the pressure release valve is opened to release the pressure in the flow path. Since the pressure does not increase above the specified value, the occurrence of the water hammer phenomenon can be suppressed.

According to a second aspect of the present invention, in the first aspect of the invention, 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 and held in the flow path. It is provided with a heat retention control means capable of performing a heat retention operation for keeping the water kept warm. According to this configuration, since the warming operation is performed while the tapping is stopped, the hot water temperature rises in a short time from the start of tapping, and the feeling of cold water hardly occurs.

According to a third aspect of the present invention, in the second aspect of the present invention, the water hammer suppressing means operates the pressure relief valve when the pressure detected by the pressure sensor immediately before the ignition of the gas burner is equal to or higher than the specified value during the warm-up operation. It is to open.
According to this configuration, the pressure relief valve is controlled by detecting the pressure before the pressure is increased due to the heating of the retained water when performing the heat retention operation. The shooting phenomenon can be reliably prevented.

[0010]

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 city water flows, and a water supply port 12 for discharging water, and the water supply port 11 and the water supply port 12 are connected to each other. A heat exchanger 13 is provided on the flow path therebetween. Heat exchanger 1
3 is stored 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 the hot water discharged from the hot tap 12 is disposed near the hot tap 12, and further detects the temperature of the hot water discharged from the heat exchanger 13. A temperature sensor 33 for performing the operation 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. Water inlet 11 and tap 1
A pressure sensor 36 for detecting the water pressure in the flow path is provided at an appropriate position on the flow path between the flow path 2 and the vicinity (for example, in the vicinity of the tap hole 12). A pressure relief valve 37 is connected to the tap hole 12. Fuel gas is supplied to the gas burner 21 from a gas connection port 22 through a main gas valve 23 and a gas proportional valve 24 which are electromagnetic valves.

By the way, the original gas valve 23 and the gas proportional valve 2
4, the flow rate sensor 31, the temperature sensors 32-34, the flow rate control valve 35, the pressure sensor 36, and the pressure relief valve 37 are shown in FIG.
As shown in (b), it is connected to a control circuit 30 composed of a microcomputer. The control circuit 30 ignites the gas burner 21 based on the inputs from the flow rate sensor 31, the temperature sensors 32 to 34, and the pressure sensor 36 in the procedure shown in FIG. It controls the gas proportional valve 24, the flow control valve 35, and the pressure relief valve 37.

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 The valve 24 is opened to ignite the gas burner 21 (S2). Although the ignition means of the gas burner 21 is not shown, a means for continuously generating and igniting a spark is used. When the ignition of the gas burner 21 is detected by a flame sensor (not shown), the spark is stopped. Is used. This type of ignition means is well known. After the ignition of the gas burner 21, the tapping temperature is adjusted by using the gas proportional valve 24 and the flow control valve 35 so that the tapping temperature detected by the temperature sensor 33 becomes a preset 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 path generally decreases. Here, the pressure detected by the pressure sensor 36 is compared with a specified value set high enough to cause the water hammer phenomenon (S6). When the detected pressure is smaller than the specified value, the pressure relief valve 37 is closed (S7). ), The warming operation by the warming control unit (warming control means) 30a provided in the control circuit 30 is started. In the warming operation, the temperature sensor 3
When the temperature detected by 2 to 34 falls to the preset reheating temperature (S8), the gas burner 21 is intermittently ignited for a fixed time (S9). As a result, the temperature of the retained water is increased before the temperature of the retained water decreases to a temperature that causes a feeling of cold water (that is, a temperature of the water that is felt very cold when touched with a hand). 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, even if the gas burner 21 is ignited, the temperature sensor 32
The temperature detected by .about.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 is obtained. All the temperature sensors 3 are used to detect the temperature during the warm-up operation.
It is not necessary to use the temperature sensors 2 to 34, and only one of the temperature sensors 32 to 34 may be used.

On the other hand, when the pressure detected by the pressure sensor 36 is equal to or higher than the specified value (S6), the water hammer suppression unit (water hammer suppression means) of the control circuit 30 determines that a water hammer phenomenon may occur. 30b, the pressure relief valve 37
Is released (S10). Thus, an abnormal increase in the pressure in the flow path can be prevented, and the water hammer phenomenon can be reliably prevented. In addition, since the pressure in the flow path is detected before the gas burner 21 is ignited by the heat retention operation, it is possible to prevent the pressure in the flow path from being abnormally high due to a pressure increase caused when the gas burner 21 is heated. As a result, not only the water hammer phenomenon can be prevented but also a failure due to an abnormal pressure rise can be prevented. When the flow rate detected by the flow rate sensor 31 exceeds a predetermined value (S11), the pressure relief valve 37 is closed (S12), and the hot water is discharged.

In the above embodiment, the pressure is detected only before the gas burner 21 is intermittently ignited in the heat-retaining operation, so that the number of times of detecting the pressure is reduced. However, the pressure detected by the pressure sensor 36 is constantly monitored. You may do so.

[0016]

According to the first aspect of the present invention, there is provided 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 heats the water in the heat exchanger. A gas burner, a flow sensor for detecting the flow of water into the flow path, and an ignition control means for igniting the gas burner when a flow rate per unit time detected by the flow sensor becomes a predetermined value or more,
A pressure sensor that is disposed on the flow path and detects a water pressure in the flow path, a pressure relief valve that releases the pressure in the flow path when opened, and a pressure detected by the pressure sensor that is higher than a specified value such that a water hammer phenomenon occurs. Water hammer suppression means for opening the pressure relief valve to mitigate the water hammer phenomenon when the pressure is detected by detecting the pressure in the flow path by the pressure sensor, and when the output of the pressure sensor becomes a specified value or more. Since the pressure relief valve is opened to release the pressure in the flow path, the pressure in the flow path does not increase to a prescribed value or more, and thus there is an advantage that the occurrence of the water hammer phenomenon can be suppressed.

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 discharge water retained in the flow path. In the system equipped with a heat retention control means capable of keeping the temperature warm, the warming operation is performed while the tapping is stopped, so that the temperature of the hot water rises in a short time from the start of tapping, so that there is almost no sense of cold water. There is.

According to a third aspect of the present invention, the water hammer suppressing means opens the pressure relief valve when the pressure detected by the pressure sensor immediately before the ignition of the gas burner is equal to or higher than the specified value during the warm-up operation. The pressure relief valve is controlled by detecting the pressure before the pressure rises due to the heating of the retained water when performing the heat retention operation, so the abnormal pressure rise in the flow path is prevented and the water hammer phenomenon is reliably prevented. Has the advantage that it can be

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, wherein (a) is a configuration diagram,
(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 Insulation control part 30b Water hammer suppression part 31 Flow rate sensor 32-34 Temperature sensor 36 Pressure sensor 37 Pressure relief valve

Claims (3)

[Claims] 1. A heat exchanger provided on a flow path formed between a water supply port into which water flows in and a tap hole for discharging water, a gas burner for heating water in the heat exchanger, and the flow path A flow rate sensor for detecting water flow into the inside, ignition control means for igniting a gas burner when a flow rate per unit time detected by the flow rate sensor becomes a predetermined value or more, and a water pressure in the flow path arranged on the flow path. A pressure sensor for detecting the pressure, a pressure relief valve for releasing the pressure in the flow path when the pressure sensor is opened, and a pressure relief valve for opening the pressure relief valve when the pressure detected by the pressure sensor is equal to or higher than a specified value high enough to cause a water hammer phenomenon. A gas water heater comprising: a water hammer suppressing means for mitigating a hammer phenomenon. 2. When the flow rate per unit time detected by the flow rate sensor is less than the predetermined value, the gas burner can be intermittently ignited to keep the water held in the flow path warm. The gas water heater according to claim 1, further comprising a heat retention control means. 3. The water hammer suppression means according to claim 2, wherein the pressure relief valve is opened when the pressure detected by the pressure sensor immediately before the ignition of the gas burner is equal to or higher than the specified value during the warm-up operation. Gas water heater.