JPS638382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a small water heater with improved hot water output temperature characteristics.

[Conventional technology]

In general, water heaters with a large capacity can store a large amount of hot water at a constant temperature, so there is less variation in the hot water temperature. However, once the stored hot water is used up, even if a normal burner is activated, it takes a long time to bring the water to a boil, making it inconvenient to use. On the other hand, instant heating type water heaters with a small can capacity can provide a large amount of hot water at a constant temperature when the heat output of the burner and hot water supply match, but when using a small flow rate like a shower, the burner It repeatedly starts and stops, and the temperature of the hot water fluctuates.

The problem of running out of hot water in a water heater with a large can capacity is related to the burner capacity, so there is no way to solve it.Currently, small instant heating type water heaters have improved hot water temperature characteristics. Efforts have been made to make it easier to use.

For example, Japanese Utility Model Publication No. 49-25251 proposes installing multiple temperature sensors to obtain a composite signal, and increasing the number of temperature sensors tends to improve the hot water temperature.

[Problem that the invention seeks to solve]

However, if the number of temperature sensors increases, the method for synthesizing the output becomes complicated and costs increase. For this reason, it is desirable to stabilize the outlet water temperature with as few combinations as possible, for example, two temperature sensors, but it is possible to install the water temperature detection sensor near the water inlet, which is the usual installation location, and the outlet temperature detection sensor near the outlet. However, there was a problem in that the burner started operating as soon as hot water was taken out, and the temperature of the hot water became abnormally high when the amount of hot water was small.

[Means for solving problems]

This invention improves the temperature characteristics of hot water output by devising the mounting positions of two temperature detection sensors, 1 is a water boiler that constitutes a water heater, and 4 is a water inlet installed at the bottom of the water boiler 1. , 5 is a tap attached to the upper end of the water heater body 1. 7 is a combustion chamber formed in the lower part of the water boiler body 1; 8 is a combustion chamber 7;
This is a heat exchange chamber/silencing chamber formed in the upper part of the interior of the water boiling can body 1 following the above, and the heating burner 3 attached to the water boiling can body 1 looks into the combustion chamber 7 and blows out a flame into the combustion chamber 7. The water in the water heater body 1 is heated through the combustion chamber 7 wall and the heat exchange chamber 8 wall.

2 and 3 are temperature detection sensors using variable temperature detection elements such as hydraulic expansion type temperature switches or thermistors, and 2 is a water temperature detection sensor located approximately in the center of the water boiler between the water supply port 4 and the hot water outlet 5. It is attached to 1. Further, reference numeral 6 denotes a hot water temperature detection sensor, which is attached to the water heater body 1 near the hot water outlet 5. The set values of both temperature detection sensors 2 and 6 are set to the hot water temperature desired by the hot water temperature detection sensor 6, and the water temperature detection sensor 2 is set to a lower temperature than this.

The outputs of the temperature detection sensors 2 and 6 have an output format suitable for each sensor, and are combined using a method suitable for each temperature detection sensor 2 and 6, so that one of the temperature detection sensors 2 and 6 is heated when low temperature is detected. Activate burner 3. A burner controller 9 controls the heating burner 3.

The embodiment shown in Fig. 2 uses hydraulic expansion type temperature detection sensors 2 and 6, and when the hydraulic expansion type has contacts that close at low temperatures, they are directly connected in parallel and only one of them requires combustion. Heating with burner 3
The contacts form an OR circuit to activate the

On the other hand, the embodiment shown in FIG. 3 uses a variable temperature detection element such as a thermistor, and the change in resistance due to temperature is an analog signal, which is converted into H and L signals by AD conversion and then synthesized. That is, the partial voltages between the temperature detection sensors 2 and 6 using thermistors and the reference resistor are A-D converted by an inverter circuit into digital H and L signals, which are then synthesized by a two-input NAND circuit. The inverter circuit and NAND circuit work as one 2-input OR circuit.

Temperature detection sensors 2 and 6 using thermistors are connected to the ground side, and the reference resistor is connected to the power supply side, so the input of the composite OR circuit becomes H when the thermistor detects low temperature, while the output of the composite OR circuit is The thermistor becomes H when detecting low temperature. The output signal of the composite OR circuit drives the PNP transistor 10 through a two-input NAND circuit, and if either thermistor detects a low temperature,
The output of the NAND circuit that drives the PNP transistor 10 becomes L, current flows from the emitter to the collector of the PNP transistor 10 connected to the power supply, and the burner controller 9 starts the heating burner 3.

In order to drive the PNP transistor 10, an inverter circuit can be used instead of a NAND circuit, but by using the two-input NAND circuit, the heating burner 3 can be stopped when the tap water temperature is abnormally high. . That is, 11 is a branch circuit that divides the reference resistance of the hot water temperature detection sensor 6 by resistance, produces a high limit output as an auxiliary output, and is connected to the input of a NAND circuit that drives the PNP transistor 10. Therefore, when the hot water temperature detection sensor 6 detects an abnormally high temperature, the auxiliary output becomes L and serves to keep the heating burner 3 stopped. Even if the output of the composite OR circuit becomes H based on the output of the water temperature detection sensor 2, the heating burner 3 cannot be started.

[Explanation of action]

The present invention will be explained using the temperature distribution curve of the water temperature inside the can body shown in FIG. 4. In the graph of FIG. The horizontal axis shows the water temperature at this can body 1 position. The set temperature of the hot water temperature detection sensor 6 is the desired temperature, and the set temperature of the water temperature detection sensor 2 attached to the center of the can body 1 is a sensor temperature lower than the desired temperature.
The position and sensor temperature are appropriately set depending on the shape of the water boiler body 1, etc. Further, the movement of the temperature distribution curve is such that when the heating burner 3 is stopped and the hot water flows out from the outlet 5, water enters from the water supply port 4, and this temperature distribution curve moves upward in parallel. Furthermore, when hot water is stopped flowing out from the outlet 5 and the heating burner 3 is activated, this temperature distribution curve moves to the right. However, since the amount of heat received by the can entering the combustion chamber 7 is large, and the amount of heat radiated is large as the temperature increases, the movement to the right becomes larger in the lower part of the temperature distribution curve. The most desirable curve is the line when hot water is continuously tapped out in a well-balanced manner while the heating burner 3 is operated. Also, when heating burner 3 is activated, heat is initially used to raise the temperature of each part of the water heater, so the water temperature starts to rise after a delay, and conversely, when heating burner 3 is turned off, the temperature of each part of the water heater increases. They also tend to remain heated for a short period of time.

When cold water is supplied and the burner 3 is operated from a state where both the water inlet 4 and the hot water outlet 5 are at the same low temperature, when the burner 3 is stopped by the signal from the water temperature detection sensor 2, the curve becomes as follows, and the hot water outlet temperature detection sensor 6 When burner 3 is stopped at the signal , the curve becomes . (Even after the burner 3 has stopped, it is heated by residual heat and the curve moves slightly to the right.) Although the desired hot water exit temperature can be obtained with the curve for this purpose, the desired hot water exit temperature cannot be obtained with the curve.

The curve when hot water is supplied and the burner 3 starts operating from one curve is the curve corresponding to the signal from the hot water temperature detection sensor 6, and the curve corresponding to the signal from the water temperature detection sensor 2. According to the curve, a large amount of cold water has already entered the lower part of the can body 1, and even if the burner 3 is activated, cold water will continue to flow out from the outlet 5 for a while.

Therefore, the best temperature distribution is obtained when the hot water boiler body 1 is initially heated by the hot water temperature detection sensor 6, and when the heating burner 3 is activated during hot water supply by the water temperature detection sensor 2.

In this invention, the heating burner 3 is activated when either the hot water temperature sensor 6 or the water temperature detection sensor 2 detects a low temperature, so when heating cold water, the heating burner 3 is activated according to the curve When the burner 3 stops and hot water is taken out, the burner 3 operates according to the curve of , and the trouble of cold water coming out from the tap 5 can be prevented.

[Explanation of effects]

As mentioned above, in order to stabilize the temperature of hot water coming out of the water boiler, it is necessary to install a large number of temperature detection sensors on the can. There was a risk that the burner would activate immediately when hot water was being supplied, causing abnormal heating. In this invention, the water temperature detection sensor, which was attached to the water inlet when conventionally using two temperature detection sensors, is attached to the can body between the water inlet and the hot water outlet. The characteristics have been significantly improved. Therefore, when you use a shower, you often experience the problem of cold water when you turn down the water volume, but these problems are caused by a defect in the temperature control device of the water heater, and the temperature control system of this invention This kind of trouble did not occur with the device, and it became comfortable to use.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the state in which the invention is implemented;
3 is a circuit diagram of the same, and FIG. 4 is a graph showing a can body temperature curve. 1...Kettle body, 2...Water temperature detection sensor, 3...
... Heating burner, 4... Water supply port, 5... Hot water outlet,
6... Hot water temperature sensor.

Claims (1)

[Claims] 1 Two temperature detection sensors 2 and 6 on the water boiler body 1
is installed, both sensors 2 and 6 are configured with temperature switches or variable temperature detection elements, and both sensors 2 and 6 are configured with temperature switches or variable temperature detection elements.
In a water heater in which the heating burner 3 is controlled by a composite signal of 6, one temperature detection sensor is installed as the water temperature detection sensor 2 in the can body 1 approximately in the center between the water inlet 4 and the hot water outlet 5, and the other The temperature detection sensor is installed as a hot water temperature detection sensor 6 in the can body 1 near the hot water outlet 5, and the set value of the water temperature detection sensor 2 is set lower than that of the hot water temperature detection sensor 6, and either temperature detection is performed. A temperature control device for a water heater, characterized in that a heating burner 3 is activated when sensors 2 and 6 detect a low temperature.