JPH02259363A - Tap-controlled water heater - Google Patents

Abstract

PURPOSE:To accomplish a hot-water temperature control having an excellent follow-up characteristic which is suitable for use in winter season and contributes to making a water heater smaller in size, by a method wherein an insulated hot-water storage tank is located on the downstream side of a heat exchanger, and pumps and valves are furnished each on the downstream side of the insulated hot-water storage tank and the upstream side of the heat exchanger in a hot water path provided with an ON-OFF valve. CONSTITUTION:An ON-OFF valve 4 is furnished on a water path 3, an insulated hot-water storage tank 5 is located downstream a heat exchanger 1, and a pump 6 and a valve 7 are provided between the downstream side of the insulated hot-water tank 5 and the upstream side of the heat exchanger 1, thus forming a circulating path 8. Thereby, the hot water in the insulated hot water storage tank 5 is supplied after mixed with city water from the water path 3 until water is heated up in the heat exchanger 1 by the combustion of a burner 12 and supplied from a hot water tap 9 after hot water supply is started, so that the hot water having a specified temperature or a temperature close to the specified temperature can be used in a short time period. As the hot water in the insulated hot water storage tank 5 is supplied after mixed with city water, the hot water having a higher temperature can be stored, causing a reduction in the volume of the insulated hot-water storage tank 5 required for storing a necessary heat quantity.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an instantaneous water heater.

(Prior art) For example, in a conventional ordinary instantaneous water heater as shown in Fig. 5, the faucet at outlet a is opened to start water flow, and the tap is placed at an appropriate location along the water flow path. When the water flow switch or flow rate sensor C detects water flowing above a predetermined level, the burner d starts combustion and heats the heat exchanger e, and the hot water thus heated in the heat exchanger e passes through the water flow path. The hot water reaches the hot water outlet a, and the hot water is drawn from here. In addition, symbols f and f' are temperature detection means such as a thermistor for controlling the burner d, g is a check valve,
h is a flow rate regulating valve.

(Problem to be Solved by the Invention) In this way, in the conventional instantaneous water heater, after the hot water starts being dispensed and a flow of water exceeding a predetermined level is detected, the burner d starts combustion and the heat exchanger e starts heating. Immediately after the start of water flow, residual water in the water flow path that has not been heated at all is first discharged, and then gradually heated hot water is discharged. Therefore, as shown by the broken line in FIG. 3, it takes a relatively long time, for example, a predetermined time t2, for example 10-odd seconds, from the start of water flow until hot water at the desired working temperature is obtained.

The present invention aims to solve this problem.

(Means for Solving the Problems) The configuration of the present invention will be explained with reference to FIGS. 1 to 4 corresponding to the embodiments. 2, branched on the upstream side of the heat exchanger 1,
A water path 3 is formed that joins on the downstream side, and an on-off valve 4 is provided in the water path 3, and a heat-retaining hot water storage container 5 is provided downstream of the heat exchanger 1 in the hot water path 2. A pump 6 is provided between the downstream side of the container 5 and the upstream side of the heat exchanger 1.
and a reflux path 8 provided with a valve 7.

(Actions and Examples) Next, the operation of the present invention will be explained with reference to illustrated embodiments.

First, in the instantaneous water heater of the present invention, when the pump 6 is operated in a state where hot water is not being discharged from the hot water dispensing section 9, residual water 11 in the hot water storage capacity s5, as indicated by the two-dot chain line arrow in FIG. The hot water enters the reflux path 8 from the hot water path 2, flows through the pump 6 and the valve 7 such as a check valve, enters the hot water path 2 again, returns to the hot water storage container 5 via the heat exchanger 1, and circulates. Therefore, by appropriately firing the burner 12 at the same time as such circulation.

The temperature of the circulating water can be raised, and the hot water heated to a higher temperature (for example, around 60 to 80 degrees Celsius) than the normal operating temperature (for example, around 40 degrees Celsius) is kept warm in the hot water storage container 5. Can store hot water.

However, when the pump 6 is in a stopped state and the faucet of the hot water outlet 9 is opened, the remaining water in the hot water path 2 is discharged as clean water flows in through the water supply section 10, and this hot water is also discharged. The flow of water in the hot water path 2 due to the start is detected by the water flow switch 11 provided at a suitable location, the burner 12 for heating the heat exchanger 1 starts combustion, and the temperature of the water passing through the heat exchanger 1 begins to rise. In the present invention, the on-off valve 4
Let's open. In addition, when starting hot water, pump 6
If it is in operation, its operation is stopped.

After hot water starts to be dispensed, the remaining water in the piping on the downstream side of the thermal hot water storage container 5 is first discharged from the hot water tap section 9, and then the high temperature hot water in the thermal hot water storage container 5 is discharged. As shown in Figure 2, the hot water mixes with the tap water that has passed through the water path 3, so it is not discharged at a high temperature;
By appropriately setting the flow rate ratio of the hot water path 3 and the temperature of the hot water kept in the hot water storage container 5, hot water at a predetermined temperature suitable for normal use or a temperature close to it can be discharged.

On the other hand, depending on the flow rate of the hot water inside, residual water in the piping up to the heat exchanger 1 and clean water that has passed through the heat exchanger 1 without being heated immediately after the start of hot water flow into the thermal hot water storage container 5. The temperature of the hot water gradually decreases for a while, and the temperature of the hot water discharged from the hot water outlet 9 also decreases accordingly. It is easy to keep this decrease within an acceptable range by appropriately setting the temperature and amount of hot water to be kept warm. After a predetermined period of time has elapsed, heated hot water flows in through the heat exchanger 1, and from then on the temperature approaches the inflowing water, and when such a state is reached, the on-off valve 4 is closed. Then, as shown in FIG. 3, the discharge of clean water through the water path 3 is stopped, and from now on, only the hot water that has been heated to a predetermined temperature through the heat exchanger 1 is discharged from the hot water tap section 9 and used. be able to. From then on, hot water can be supplied using the same controls as in a normal instantaneous water heater.

In this way, in the present invention, after the start of tapping, until the hot water heated to a predetermined temperature in the heat exchanger 1 by combustion in the burner 12 is discharged from the tapping section 9, the above-mentioned Insulated hot water storage container 5 mixed with clean water from water route 3
Since the hot water inside is discharged, hot water at a predetermined temperature or a temperature close to it can be used within a short time t, as shown by the solid line in FIG. 4, for example. In particular, in the present invention, the hot water that has been kept warm in the hot water storage container 5 is not discharged as it is, but is mixed with the tap water that has passed through the water path 3 and is discharged, so that the hot water is heated to a temperature higher than the normal operating temperature. Therefore, the volume of the hot water storage container 5 required to store a predetermined amount of heat can be reduced, and the size can be reduced. The miniaturization of the heat-retaining hot water storage container 5 can contribute to shortening the delay time for hot water temperature control in this part, and can perform hot water temperature control with good followability.

The above-mentioned control of the on-off valve 4 can be performed, for example, by the following method. The first method is to control the on-off valve 4 by a timer (not shown) provided in the control means 13, and close the valve 4 after a predetermined period of time has elapsed since the start of hot water dispensing. In this method, the timer starts measuring time by detecting running water using the running water switch 11, etc., opens the on-off valve 4, and opens the on-off valve 4 after the set predetermined time measurement is completed. In the second method, the on-off valve 4 is controlled by a hot water temperature sensor 14 that detects the temperature of hot water on the downstream side of the heat exchanger 1 via the control means 13, and after the start of hot water dispensing, the temperature of the hot water on the downstream side is controlled. In this method, the valve is closed after reaching a predetermined temperature. In this method, the opening operation of the on-off valve is performed by detecting running water using the running water switch 11, etc., as in the method described above. After the hot water heated to a predetermined temperature in the exchanger 1 is discharged from the hot water outlet 9, the discharge of clean water through the water path 3 is stopped, and from then on, normal instant water boiling is performed. Hot water at a predetermined temperature can be supplied by controlling the burner 12 similar to the boiler. The burner 12 is controlled, for example, by temperature sensors 1 such as thermistors provided on the upstream and downstream sides of the heat exchanger 1.
5゜14, flow rate sensor 16 and hot water temperature setting device (not shown)
Based on this, the supply of fuel to the burner 12 can be adjusted by feedforward control or feedback control to obtain hot water at a desired set temperature.

Next, the operation control of the pump 6 described above and the combustion control of the burner 12 during operation of the pump 6 can be performed, for example, by the following method. The first method is to monitor the temperature of the hot water in the thermal hot water storage container 5, and when the hot water temperature falls below a predetermined temperature, operate the pump 6 and control combustion of the burner 12 to maintain the temperature in the thermal hot water storage container S. This is a method of raising the temperature of the water to a predetermined temperature. In this method, the temperature of the hot water in the hot water storage container 5 can be monitored by installing a temperature sensor (not shown) in the hot water storage container 5 to directly monitor the hot water temperature. 5 and the temperature sensor 14 provided between the heat exchanger 1
The second method is to operate the pump 6 at predetermined time intervals, detect the temperature of the circulating water under such operating conditions, and ensure that the temperature of the water reaches the predetermined temperature. This is a method of controlling the combustion of the burner 12 in the following cases to raise the temperature of the circulating hot water and the temperature of the hot water in the thermal hot water storage container 5 to a predetermined temperature. In this method, the temperature of the hot water can be detected by temperature sensors 14, 15, etc. installed at appropriate locations in the circulation path.

The opening/closing operation of the on-off valve 6 during hot water dispensing, the operation of the pump 6 when hot water supply is stopped, and the operation of raising the temperature of hot water in the hot water storage container 5 by combustion of the burner 12 when the pump 6 is operating as described above. In addition to making it happen all the time,
It is possible to perform the operation only when a predetermined period of time has elapsed after the hot water supply is stopped, and to keep the on-off valve 4 closed during short-term hot water supply stops, and to control the heating operation so as not to perform the heating operation. can. The latter control prevents the on-off valve 4, pump 6, burner 12, etc. from operating more than necessary during short periods of intermittent use during the day, and also prevents the operation of the on-off valve 4, pump 6, burner 12, etc. when they are not used for long periods at night. may perform certain of the aforementioned operations.

In the illustrated embodiment, reference numeral 17 indicates that when the hot water load exceeds the capacity of the burner 12, priority is given to the set temperature.
This is a flow rate adjustment valve for dispensing hot water at a reduced flow rate. Further, the heat retaining structure in the heat retaining hot water storage container 5 can be constructed as appropriate, such as a structure covering a new heat material or a heat storage material. Further, by forming the valve 7 as a check valve as described above, the configuration and control can be simplified by eliminating the need for operations such as applying current.

(Effects of the Invention) As described above, in the hot water path passing through the heat exchanger of a water heater, the present invention provides a hot water storage container downstream of the heat exchanger, and a downstream side of the hot water storage container. A reflux path including a pump and a valve is configured between the upstream side of the heat exchanger, and when hot water is not being tapped, the heat exchanger heats while circulating hot water through a circulation system consisting of the reflux path and the hot water path. The hot water heated to a predetermined temperature is stored in the thermal hot water storage container by burning a burner, and this hot water is used when hot water is dispensed.
Once the faucet of the hot water outlet is opened and hot water begins to flow, hot water at or close to the desired temperature can be used within a short period of time, making it suitable for use in winter. In particular, the present invention configures a water path in parallel with the hot water path passing through the heat exchanger, and mixes hot water from the thermal hot water storage container with tap water from the water path for a while after hot water starts being tapped. Since hot water is dispensed from the hot water tank, hot water at a temperature higher than the normal operating temperature can be stored in the hot water storage container, and the volume of the hot water storage container required to store a predetermined amount of heat can be reduced. In addition to contributing to the miniaturization of the boiler as a whole, the miniaturization of the insulating hot water storage container can also contribute to shortening the delay time for hot water temperature control in this part, making hot water temperature control with good followability possible. The effect is that it can be done.

Further, the present invention has the effect that an auxiliary heating source such as an electric heater is not required because the temperature of the hot water in the hot water storage container is raised using a burner that is used to raise the temperature during normal hot water dispensing.

[Brief explanation of drawings]

1, 2, and 3 are system explanatory diagrams showing the overall configuration and operation of the embodiment of the present invention, FIG. 4 is an explanatory diagram showing the hot water output characteristics of the present invention and the conventional example, and FIG. 5 is a system explanatory diagram of a conventional example. Code 1...Heat exchanger, 2...Hot water route, 3...Water route, 4...Opening/closing valve, 5...Heat hot water storage container, 6...
Pump, 7...Valve, 8...Recirculation route, 9...Hot water outlet, 10...Water supply part, 11...Water switch, 12
... Burner, 13... Control means, 14.15...
Temperature sensor, 16...Flow rate sensor, 17...Flow rate adjustment valve. Figure 6 Shi2

Claims (6)

[Claims] (1) In parallel with the hot water path passing through the heat exchanger of the water heater, configure a water path that branches on the upstream side of the heat exchanger and merges on the downstream side, and provides an on-off valve in the water path, and A thermal hot water storage container is provided downstream of the heat exchanger in the hot water path, and a reflux path is configured with a pump and a valve between the downstream side of the thermal hot water storage container and the upstream side of the heat exchanger. An instantaneous water heater characterized by (2) An instantaneous water heater characterized in that the on-off valve described in paragraph 1 is configured to be controlled by a timer, and stops the flow of water through the water path after a predetermined period of time has elapsed from the start of hot water dispensing. (3) The on-off valve described in paragraph 1 is configured to be controlled by a temperature sensor that detects the temperature of water on the downstream side of the heat exchanger, and after the start of hot water dispensing, the water temperature on the downstream side reaches a predetermined temperature. An instantaneous water heater characterized by stopping the flow of water through a path. (4) The thermal hot water storage container described in paragraph 1 is an instantaneous water heater characterized by storing hot water at a temperature higher than the normal operating temperature. (5) In the water heater described in paragraph 1, the pump and burner are controlled by monitoring the temperature of the water in the insulating hot water storage container to raise the temperature of the water in the insulating hot water storage container to a predetermined temperature. Characteristic instantaneous water heater (6) In the water heater described in paragraph 1, the pump is operated at predetermined time intervals, and the temperature of the circulating water is detected in this operating state and the burner is controlled so that the temperature inside the hot water storage container is increased. An instantaneous water heater characterized by raising the temperature of water to a predetermined temperature.