JP2921176B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater mainly for domestic use, which uses oil or gas as a heat source.

In general, instantaneous water heaters cause post-boiling due to after-burning after the operation is stopped or the release of heat retained by the combustion burner, and the hot water remaining in the heat exchanger becomes hot when re-watering. It is a problem in use. In order to reduce boiling after this, a large mixing tank was provided at the outlet of the heat exchanger to reduce the fluctuation of hot water temperature, or during hot water tapping, always mixing water and hot water to discharge hot water, thereby reducing post-boiling. .

[0003]

In such a conventional mixing tank system, a high-capacity tank is required in order to reduce the fluctuation of the tapping temperature by mixing high-temperature water after boiling in the tank when a comfortable tapping is desired. Also, when mixing water and hot water at all times during tapping, the temperature of the tapping water from the heat exchanger must be set higher than the actual tapping temperature. Stress is applied and durability is reduced. Further, in order to prevent boiling in heat exchange and to prevent an increase in pressure stress due to an increase in internal pressure of the heat exchanger generated at the time of boiling, the high temperature in the heat exchanger cannot be set too high. Therefore, when the hot water and the water are mixed and discharged, the mixing ratio of the hot water and the water is limited in order to secure the hot water temperature, so that comfortable hot water supply cannot be expected.

[0004] Therefore, an object of the present invention is to provide a compact hot-water supply device that reduces hot water tapping at the start of tapping due to boiling afterwards and has little variation in hot water temperature.

[0005]

In order to solve the above-mentioned problems, a water heater according to the present invention comprises a heat exchanger, a burner for heating water supplied to the heat exchanger, and a flow rate provided on the inlet side of the heat exchanger. A sensor, a feed water temperature detector, a hot water supply circuit provided with a hot water temperature detector at an outlet side of the heat exchanger, and a bypass water feed circuit connecting an inlet side and an outlet side of the heat exchanger via an electromagnetic valve, A controller for controlling the opening and closing operation of the solenoid valve;
The controller detects with the flow sensor at the start of hot water supply operation
Open the solenoid valve for the time determined according to the amount of water
With the hot water temperature detector and the water temperature detector
The opening time of the solenoid valve is compensated based on the measured hot water temperature and water temperature.
It is obtained as a positive to.

[0006]

According to the present invention, at the start of the hot water supply operation,
Water supply and hot water temperature detector detected by flow sensor and water supply
It is a time determined based on the hot water temperature and water temperature detected by the temperature detector
The solenoid valve is opened to heat water through the bypass water supply circuit.
So that it can be supplied to the hot water supply circuit on the outlet side of the exchanger.
High temperature post-boiled water remaining in the heat exchanger
It is not discharged from the gate and bypass
The amount of water supplied from the water circuit is also detected by the flow sensor.
Controls to the optimal amount according to the water volume, hot water temperature, and water temperature
Hot water supply with little fluctuation in hot water temperature
You.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a heat exchanger 1 is provided above a combustion burner 2.
The heat exchanger 1 is configured such that feed water is heated by combustion heat of the combustion burner 2. On the inlet side of the heat exchanger 1, a flow rate sensor 3 for detecting the flow rate of the feed water, a feed water temperature detector 4 for detecting the feed water temperature, and a hot water temperature detector 5 for detecting the hot water temperature at the outlet are provided. The hot water supply circuit 6.

A solenoid valve 7 is provided between the inlet and the outlet of the heat exchanger 1.
Is connected to the hot water heated by the heat exchanger 1 at the outlet of the heat exchanger 1 without heating a part of the feed water by the heat exchanger 1. . Controller 9
Controls the amount of combustion of the combustion burner 2 and the solenoid valve 7 based on signals from the flow rate sensor 3, the feed water temperature detector 4, and the hot water temperature detector 5.

In the above configuration, first, the opening time of the solenoid valve 7 is changed according to the amount of water supply based on the sequence of FIG.
The operation will be described. When the tapping is started, the flow rate sensor 3 detects the flow rate, and the control unit 9 operates to open the solenoid valve 7 for a time corresponding to the flow rate set in advance,
It closes after the set time. That is, water flows into the bypass water supply circuit 8 simultaneously with the start of hot water supply, and is mixed with the hot water heated by the heat exchanger 1 in the mixing section 10. The bypass flow rate and the open setting time are settings that minimize the amount of after-boiling. And,
Lowering temperature of the hot water which occurs after boiling rear set so as to minimize, (open setting time is measured is rather short in large flow rate, at a small flow rate
Good results have been obtained by setting the rather long. ) Reduce post-boiling to suppress hot water temperature fluctuations.

Next , when the solenoid valve 7 is opened based on the hot water temperature and the water temperature.
The correction operation during this period will be described with reference to FIG . Water temperature detector 4 immediately before starting the hot water out, by detecting the water temperature and water temperature in the hot water supply temperature detector 5 controls the combustion amount of the burner 2 by the control unit 9, the solenoid valve based on the detection value 7 is configured to correct the opening time, and is set according to the flow rate.
That is corrected by influencing the water temperature and YuAtsushi the mixed hot water opening time of the solenoid valve 7, supplied from the bypass water supply circuit 8
Water volume can be set to an optimal value,
No stable hot water supply temperature can be ensured.

[0011]

As described above, according to the water heater of the present invention, the following effects can be obtained. (1) Since the opening time of the bypass water supply circuit can be set to an optimal amount by changing the flow time of the bypass water, which varies depending on the flow rate, it is possible to reduce the after-boil and the fluctuation of the hot water temperature. (2) Since the water temperature and the water temperature immediately before tapping are detected and the flow time of the bypass water is corrected, the water temperature and the water temperature change are stable, and the after-boiling and the fluctuation of the water temperature are further reduced. Can do exactly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a water heater according to an embodiment of the present invention.

FIG. 2 is a sequence diagram in the first embodiment.

FIG. 3 is a sequence diagram in a second embodiment.

FIG. 4 is a sequence diagram in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Burner 3 Flow rate sensor 4 Supply water temperature detector 5 Hot water supply temperature detector 7 Solenoid valve 9 Controller

Claims (1)

(57) [Claims] 1. A heat exchanger, a burner for heating water supplied to the heat exchanger, a flow sensor provided on an inlet side of the heat exchanger, a water supply temperature detector, and a hot water supply on an outlet side of the heat exchanger. a hot water supply circuit having a temperature detector, a bypass water supply circuit of the port side out with the heat exchanger inlet side is connected through an electromagnetic valve, the electric
A controller for controlling the opening and closing operation of the magnetic valve, wherein the controller is
At the start of hot water supply operation, the amount of water detected by the
Open the solenoid valve for the time determined accordingly,
The hot water temperature detected by the hot water temperature detector and the hot water temperature detector
And correcting the opening time of the solenoid valve based on the temperature and the water temperature.
Water heater was.