JPH0142765Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a device for preventing a drop in the temperature of tapped water that occurs when hot water is re-discharged in a water flow control instantaneous water heater.

[Prior art]

Conventionally, a water flow control type instantaneous water boiler calculates the flow rate that can be heated to a set temperature based on a set heating capacity, water supply temperature, and set temperature, and controls a water flow control valve to achieve the target flow rate. In the case of a boiler, when you try to re-dispense hot water at around the minimum operating water flow by closing the switch and opening it again, the amount of water at the start of re-dispensing will be lower than the minimum operating water flow due to the drop in water pressure that occurs while the switch is closed. It may happen that the combustion device is not ignited. In order to eliminate such a situation, conventionally, a program is incorporated into the control circuit as a sequence to output a control signal to fully open the water flow control valve when the flush valve is closed. However, in such a conventional example, since the flow rate when hot water is re-discharged is a full-open flow rate, a large amount of cold incoming water flows as an inrush flow rate when hot water is re-discharged, and the hot water temperature drops significantly as shown in Figure 2b. There is.

[Purpose of invention]

The present invention has been proposed with the aim of eliminating the drawbacks of such conventional examples.

[Structure of the idea]

In order to achieve this purpose, this invention
A water flow control valve is provided to control the amount of hot water dispensed, and the water flow control valve is configured to be able to be opened/closed and controlled by a control section via a drive section, and the control section is configured such that the target flow rate and hot water output amount exceeds the minimum operating flow rate when the tap is closed. If the water flow rate is greater than or equal to a predetermined value, the water flow rate control valve is stopped at the control position, and if the water flow rate is less than the predetermined value, a control signal is output that sets the control target flow rate of the water flow rate control valve to a specific value that is greater than or equal to the predetermined value for a predetermined period of time. Configure it to do so.

〔Example〕

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a block diagram schematically showing an instantaneous water heater according to an embodiment of the present invention. In the figure, 1 is an inlet waterway, 2 is a heat exchanger, 3 is an outlet waterway, 4 is a flow rate sensor interposed in the inlet waterway 1, 5 is a water temperature sensor, for example, a thermistor, also interposed in the inlet waterway 1,
Reference numeral 6 denotes a hot water temperature sensor consisting of a thermistor interposed in the hot water outlet path, 7 a water flow control valve also interposed in the hot water outlet path 3, 8 a drive unit consisting of a servo motor that drives the water flow control valve 7, and 9 . . . burner, 10... is a fuel control valve consisting of each electromagnetic valve for controlling the supply of fuel to each burner 9... and its stop; 11 is a gas governor; 12 is a fuel valve consisting of an electromagnetic valve; 13 is the entire fuel supply path. , 14 is a control circuit, and 15 is a control operating device, which has a capacity setting device 151 for arbitrarily setting the number of combustions of the burners 9, and a hot water temperature setting device 152 for adjusting the hot water temperature. Reference numeral 16 indicates a collar provided at the end of the hot water outlet path 3. The control circuit 14 is composed of, for example, a microcomputer, and controls the amount of water Q detected by the water amount sensor 4.
If it is above a predetermined value, heating by the burner is started, and the water supply temperature Tin detected by the water temperature sensor 5 is
Based on the capacity W set by the capacity setting device 151 and the set temperature Tset set by the hot water temperature setting device 152,
The flow rate Qo that can be heated to the set temperature is calculated using the following relationship: Qo=W×25/(Tset−Tin), and the water flow control valve 7 is adjusted to achieve this target flow rate. Also, when the plug 16 is closed, the above target flow rate is the predetermined minimum operating hot water flow rate (M, O,
When the water flow rate is higher than a predetermined value, for example, 5/min or more, the water flow control valve 7 is stopped at that position, and when it is below the predetermined value, the water flow control valve 7 is fully opened for a predetermined period of time, for example, about 2 seconds. A program for outputting a control signal to the drive section 8 is incorporated as a sequence. Further, when the flow rate detected by the flow rate sensor 4 is less than 1.5/min, the control circuit 14 determines that the cutter is closed, and is configured to stop the control operation of the burner 9.

In the instantaneous water heater configured in this way, when the tap 16 is closed and then the tap 16 is opened again to dispense hot water again, the amount of hot water Q at the time of re-dispensing hot water is equal to or greater than the predetermined value. is the opening degree of the water flow control valve 7 when the valve is closed, and restarts with the amount of hot water output when the valve is closed, so the amount of incoming water rises above the predetermined value almost at the same time as hot water starts flowing again, so ignition is impossible due to insufficient flow rate. In this case, the amount of water Q
Since the hot water output amount Q is suppressed to less than the full opening water flow, the inrush flow rate of cold water at the time of re-starting hot water supply is smaller than before, and the drop in the hot water temperature can be effectively reduced as shown in Fig. 2 a, for example. . In addition, since the water flow control valve 7 is fully opened for a predetermined period of time, that is, about 2 seconds when the water is below the predetermined value, there is no possibility that ignition will fail due to insufficient flow when re-releasing hot water. Furthermore, in this instantaneous water heater, even when re-dispensing hot water in a low-capacity operation where the number of burners 9 to be burned relative to the amount of dispensing hot water is, for example, three or less, for a predetermined period of time from the start of re-dispensing hot water,
For example, by incorporating a program into the control circuit 14 as a sequence to switch the number of burners 9 that are ignited for about 2 seconds to a large capacity larger than the hot water dispensing capacity, for example, five burners corresponding to the maximum capacity, when re-dispensing hot water, It is possible to further reduce the drop in the tap water temperature and further improve the hot water tap characteristics.

〔effect〕

As explained above, according to the present invention, the water flow rate regulating valve is configured to be open/close controlled by the control unit via the drive unit, and the control unit is controlled at a predetermined point where the amount of hot water when the tap is closed exceeds the minimum operating flow rate. Since the system is configured to output a control signal that sets the control target flow rate of the water flow rate control valve to a specific value greater than or equal to the predetermined value for a predetermined period of time when the water flow rate is below the predetermined value, the amount of water inflow will never fall below the minimum operating flow rate. In addition, when the amount of water flowing in exceeds the predetermined value, the inrush flow rate at the start of hot water re-discharge can be suppressed to be lower than the full-open flow rate, and the temperature of the hot water due to the inflow of hot water during re-discharge can be reduced. can reduce the drop in

[Brief explanation of drawings]

Fig. 1 is a block diagram schematically showing an automatic capacity switching instantaneous water heater according to an embodiment of the present invention, and Fig. 2a
2 is a hot water discharge characteristic diagram thereof, and FIG. 2b is a hot water discharge characteristic diagram of a conventional example. 7...Water flow control valve, 8...Drive unit, 14...Control unit.

Claims (1)

[Scope of utility model registration request] A water flow rate regulating valve is provided to control the amount of hot water dispensed, and the water quantity regulation valve is configured to be open/closed and controlled by a control unit via a drive unit, and the control unit is configured to operate at a predetermined level where the amount of hot water dispensed when the tap is closed exceeds the minimum operating flow rate. An instantaneous water heater configured to output a control signal that sets the control target flow rate of the water flow rate control valve to a specific value equal to or higher than the predetermined value for a predetermined period of time when the water flow rate is below the predetermined value.