JPH02290463A - Instantaneous water heater - Google Patents

Abstract

PURPOSE:To enable the use of hot water at a desired temperature or near it in a short time as soon as the hot water is discharged by providing a lagged hot-water storage vessel in the downstream side of a heat exchanger in a hot water passage and setting a electric heater on the heat insulation hot water storage vessel. CONSTITUTION:After the discharge of hot water is started, the hot water in a lagged hot-water storage vessel 7 mixed with upper water from a water passage 3 is discharged until the hot water increased up to a specified temperature in a heat exchanger 1 with the use of combustion of a burner 1 is discharged from a hot water discharge part 9. Accordingly, in a short time (t) the hot water at the specified temperature or near it can be used. Since the hot water kept warm in the lagged hot-water storage vessel 7 is not discharged as it is and mixed with upper water through a water passage 3 to discharge, higher temperature hot water than normal use temperature can be stored. Therefore, the volume of the heat insulation hot water storage vessel necessary for storing a specified heating value can be lessened and miniaturized.

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, water is started to flow by opening the faucet at the outlet a, and the faucet, etc. When the water flow switch or flow rate sensor C detects water flowing at a predetermined level or higher, 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 b. 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, the residual water in water flow path b that has not been heated at all is discharged first, and then gradually heated hot water is discharged. Therefore, as shown by the broken line in Figure 4? It took a relatively long time, for example, 10-odd seconds, from the time the water was started until the hot water at the desired temperature for use was obtained.

The present invention provides a water path that branches off on the upstream side of the heat exchanger and merges on the downstream side in parallel with the hot water path that passes through the heat exchanger of the water heater, and the water path and the hot water path have a flow rate ratio. In addition to having a configuration in which they are merged via an adjustable mixing valve, a temperature detection means is provided near the downstream side of the mixing valve, and the mixing valve is controlled by a control means based on the hot water temperature detected by the temperature detection means and the set field temperature. The purpose of this project is to solve this problem by rationally configuring an instantaneous water heater that uses feedback control to change the flow rate ratio and control the water temperature.

(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 provided for merging on the downstream side, and the water path 3 and the hot water path 2 are configured to merge or diverge via a mixing valve 4 whose flow rate ratio can be adjusted. A temperature detecting means 5 is provided, and the mixing valve 4 is controlled by the control means 6 based on the hot water temperature detected by the temperature detecting means 5 and the set hot water temperature.
In the instantaneous water heater configured to control the hot water temperature by changing the flow rate ratio through feedback control of the hot water path 2,
A heat-retaining hot water storage container 7 is provided downstream of the heat exchanger 1, and an electric heater 8 is provided in the heat-retaining hot water storage container 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, as shown in FIG. temperature to a specified temperature, and the normal operating temperature (e.g. 4
It is possible to keep hot water heated to a higher temperature (e.g., around 60 to 80 degrees Celsius) than the temperature (around 0 degrees Celsius). However, when the faucet of the hot water outlet 9 is opened, the water supply section 10
The remaining water in the hot water path 2 is discharged as clean water flows in through the hot water, and when the water flowing in the hot water path 2 due to the start of hot water discharge is detected by the water flow switch 11 installed at an appropriate location, the heat exchanger 1
The heating burner 12 starts combustion, and the temperature of the water that passes through the heat exchanger 1 begins to rise. After the water is discharged, the high-temperature hot water in the thermal hot water storage container 7 and the clean water that has passed through the water path 3 are mixed by the mixing valve 4 and discharged. At this time, the mixing valve 4 performs feedback control by the control means 6 based on the temperature detection means 5 provided near the downstream side and the set hot water temperature to change the flow rate ratio and control the hot water temperature. In this way, the hot water storage container 7
The high-temperature hot water inside is not discharged as it is, but can be discharged at a predetermined temperature suitable for normal use or at a temperature close to it.

On the other hand, in response to the outflow of hot water inside, there is residual water in the piping up to the heat exchanger 1 in the thermal hot water storage container 7, and tap water that has passed through the heat exchanger 1 without being heated because it has just started hot water dispensing. As the water flows in, the temperature of the hot water gradually decreases for a while, and therefore the mixing ratio of the mixing valve 4 gradually becomes larger in the hot water path 2 than in the water path 3. When a predetermined period of time has elapsed in this manner, the heated hot water passes through the heat exchanger 1 and flows into the thermal hot water storage container 7, and from then on, the hot water heated to a predetermined temperature in the heat exchanger 1 flows through the hot water path. The hot water from No. 2 and the tap water that has passed through the water path 3 are mixed at the mixing valve 4 as described above, and the hot water is fed out under feedback control to a predetermined hot water temperature. 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 process is performed. Insulated hot water storage container 7 mixed with tap 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 7 is not discharged as it is, but is mixed with the clean water that has passed through the water path 3 before being discharged. Hot water can be stored therein, and therefore the volume of the hot water storage container 7 required to store a predetermined amount of heat can be reduced, resulting in miniaturization. The miniaturization of the heat-retaining hot water storage container 7 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 temperature of the hot water is measured by a temperature detection means 5 provided downstream of the mixing valve 4, that is, near the common output side.
Since the above-mentioned feedback control is performed based on the detection, the delay time of the control is small, so hunting is less likely to occur, and stable hot water temperature control can be performed. In particular, if a mixing valve that can adjust the flow ratio without changing the total flow rate of the water system 3 and the hot water system 2 is used as the mixing valve 4, the flow rate will not change during control, and hot water temperature control will be easy.

In addition, in the above operation, the burner 12 may be controlled to burn at maximum capacity at all times, or the amount of hot water and
Based on the set temperature and the temperature of the tap water supplied from the water supply section 10, the amount of combustion in the burner 12 can be appropriately controlled by a proportional control valve or the like so that the necessary amount of heat can be given to the water. . The amount of hot water dispensed in the latter control can be detected, for example, by using the flow rate detection means 13 capable of detecting the flow rate in the common path, or by each of the flow rate detection means 14 and 14' provided in both the hot water path 2 and the water path. It is also possible to detect the sum of the flow rates. Further, the temperature of the tap water and the temperature of the hot water on the downstream side of the heat exchanger 1 can be detected as appropriate by temperature sensors 15, 15'.

The above-described operation of raising the temperature of the hot water in the thermal hot water storage container 7 by the electric heater 8 when the hot water supply is stopped is not only performed at all times, but also performed only when a predetermined time has elapsed after the hot water supply is stopped. When the hot water supply is stopped for a short time, the temperature raising operation can be controlled not to be performed. The latter control prevents, for example, the electric heater 8 from operating more than necessary when it is used intermittently during the day, and also prevents the electric heater 8 from operating more than necessary when it is not used for a long time at night. It can be performed.

Next, to explain a specific example of the mixing valve 4, the mixing valve 4 shown in FIG. Valve body 17 that rotates with etc.
The valve body 17 is arranged and configured such that the rotational force that opens the flow path on one side of the hot water input side U or the water input side V is the direction that closes the flow path on the other side. This is what I did. In this configuration, Fig. 3(b) shows a state where the flow rates on the hot water path 2 and water path 3 sides are equal, and Fig. 3(c) shows a state where the flow rate on the hot water path 2 side is higher than the flow rate on the water path 3 side. It also represents a situation where there are many In such a configuration, by appropriately designing the valve body 17 and the flow paths of the hot water input side U and the water input side V, it is possible to easily configure the total flow rate so that it does not change even if the flow rate ratio is changed. I can do it. In addition to this configuration, the specific configuration of the mixing valve is arbitrary. In the illustrated example, the mixing valve 4 is provided on the merging side of the hot water path 2 and the water path 3, but it goes without saying that it may be provided on the branching side. Moreover, the electric heater 8 is
The structure installed in the thermal hot water storage container 7 and the thermal hot water storage container 7
A structure in which the material is wrapped around the outside of the material may be used as appropriate.

In the illustrated embodiment, reference numeral 18 denotes a flow rate adjustment valve for dispensing hot water with priority given to the set temperature and a reduced flow rate of hot water when the hot water supply load exceeds the capacity of the parner 12, and 22 a check valve. It is. Further, the heat retaining structure in the heat retaining hot water storage container 7 can be appropriately configured such as a structure covering a heat insulating material or a heat storage material. Further, the electric heater 8 may have an appropriate configuration, such as a configuration in which it is installed inside the heat-retaining hot water storage container 7, or a configuration in which it is wrapped around the outside of the heat-retaining hot water storage container 7.

(Effects of the Invention) As described above, the present invention provides a water path that branches off on the upstream side of the heat exchanger and joins on the downstream side in parallel with the hot water path that passes through the heat exchanger of the water heater. The route and the hot water route are configured to join together via a mixing valve that can adjust the flow rate ratio, and a temperature detection means is provided near the downstream side of the mixing valve, and the hot water temperature detected by the temperature detection means and the set hot water temperature are In an instantaneous water heater configured to control the hot water temperature by controlling the mixing valve by feedback control using a control means to change the flow rate ratio based on In addition to providing a container, an electric heater is provided in the thermal hot water storage container, and hot water heated to a predetermined temperature is stored in the thermal hot water storage container when bathing is not performed, and this hot water is used when hot water is dispensed. Once the faucet or the like 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 during the winter. In particular, in the present invention, a water path is configured in parallel with the hot water path passing through the heat exchanger, and hot water from the thermally insulated hot water storage container and tap water from the water path are mixed and tapped. The container can store hot water at a higher temperature than the normal operating temperature, so the volume of the insulating hot water storage container required to store a given amount of heat can be reduced, which contributes to the miniaturization of the entire instantaneous water heater. The miniaturization of such a hot water storage container can contribute to shortening the delay time for hot water temperature control in this part, and together with the hot water temperature control using the mixing valve, it is possible to achieve hot water with good followability. This has the effect of being able to control temperature.

[Brief explanation of drawings]

1 and 2 are system explanatory diagrams showing the overall configuration and operation of an embodiment of the present invention. FIGS. 3(a) and 3(b) are cross-sectional explanatory diagrams showing the configuration and operation of a mixing valve. FIG. 4 is an explanatory diagram showing the hot water discharge characteristics of the present invention and the conventional example, and FIG. 5 is a system explanatory diagram of the conventional example. Code 1... Heat exchanger, 2... Hot water route, 3... Water route, 4... Mixing valve, 5... Temperature detection means, 6...
Control means, 7... Thermal hot water storage container, 8... Electric heater, 9... Hot water outlet, 10... Water supply unit, 11... Water flow switch, 12... Burner, 13, i4, 14 '...
・Flow rate detection means, 15, 15'...Temperature sensor, 16
...Motor, 17...Valve body, 18...Flow rate adjustment valve, 19...Check valve.

Claims (2)

[Claims] (1) In parallel with the hot water path that passes through the heat exchanger of the water heater, provide a water path that branches on the upstream side of the heat exchanger and merges on the downstream side, and adjust the flow rate ratio between the water path and the hot water path. In addition, a temperature detection means is provided near the downstream side of the mixing valve, and the water temperature is mixed by a control means based on the hot water temperature detected by the temperature detection means and the set water temperature. In an instantaneous water heater configured to control hot water temperature by changing a flow rate ratio through feedback control of a valve, a hot water storage container is provided in the hot water path downstream of the heat exchanger, and the hot water storage container is provided in the hot water path downstream of the heat exchanger. An instantaneous water heater characterized by having an electric heater installed in the container. (2) 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.