JPH0245783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a configuration that contributes to preventing local boiling and improving hot water supply performance of hot water boilers used in water heaters and household heating equipment.

Conventional configuration and its problems Conventional hot water boilers of this type are shown in Figures 1 and 2.
As shown in the figure, a first header 1 and a second header 2, which were formed in an annular shape, are connected by a large number of water pipes 3, and a water pipe wall 4 made of these water pipes 3 is formed.
A combustion chamber 5 was formed inside this water tube wall 4. A water supply pipe 6 and a hot water supply pipe 7 were arranged above the first header 1. The tip of the water supply pipe 6 located inside the first header 1 is closed, and a water supply port 8 is provided on the circumferential surface and in a substantially tangential direction of the first header 1.
was opened. A temperature sensor 9 was installed inside the first header 1. The burner 10 was arranged in the combustion chamber 5 on the second header 2 side.

Since the high-temperature combustion gas generated from the burner 10 exchanges heat with the water pipe 3, the inside of the water pipe 3 becomes a flow field dominated by natural convection, and the hot water rises to the first
Flows into header 1. Water 11 is supplied from the water supply port 8 in the tangential direction as shown by the arrow, and the water is supplied to the first header 1.
While flowing inside, the hot water rapidly mixed with the hot water flowing in from the water pipe 3, and hot water of uniform temperature was supplied from the hot water supply pipe 7.

In this configuration, the temperature distribution inside the first header 1 is made uniform by rapid mixing of the water 11 and hot water, so stable temperature detection can be easily performed inside the first header 1, and the temperature distribution can be directly connected to the water pipe 3. In order not to supply water,
Although the generation of dew condensation water on the surface of the water pipe 3 can be prevented, it has the following problem.

As shown in Fig. 3, the hot water in the water pipe 3 mixes with the supplied water 11 and lowers the temperature before supplying hot water, so the temperature in the water pipe 3 becomes higher than the hot water temperature. Of course. Therefore, if the temperature detector 9 is set so that the hot water temperature is around 80°C, the inside of the water pipe 3 will be in a state where it is likely to boil. Further, when hot water supply is stopped, the temperature inside the water pipe 3 increases due to a delay in extinguishing the burner 10 due to a delay in temperature detection by the temperature detector 9. Therefore, when the hot water supply temperature is set high and the hot water supply is stopped, there is a problem in that local boiling is likely to occur within the water pipe 3 due to a delay in temperature detection. This boiling causes the first
The header 1 and water pipe 3 are prone to corrosion, scale accumulates, and a vapor phase is formed between the water pipe 3 and water 11, resulting in a decrease in thermal efficiency.

As shown in FIG. 3, when hot water is restarted after hot water supply has been stopped, the temperature of the supplied water gradually decreases due to the ignition delay of the burner 10 due to the delay in temperature detection by the temperature detector 9, and the set hot water temperature is reset again. The problem is that it takes time to obtain the desired results.

As a solution to the delay in temperature detection by the temperature detector 9, it has been considered to provide the temperature detector 9 inside the water pipe 3, where temperature fluctuations are large and rapid, as shown in FIG. 3, to speed up the temperature detection. Since the amount of canned water in the water tube 3 is small, the temperature inside the water tube 3 is much higher than the temperature inside the first header 1, which is a very thermally unbalanced state. As shown in FIG. 4, the joint between the first header 1 and the water pipe 3 is
Since the water pipe has a shape that rapidly expands with respect to the flow, eddies may occur at the joint on the water pipe 3 side, and the water 11 may descend down the water pipe 3 as if caught in the eddy. Due to the thermal imbalance and eddying of the temperature within the water pipe 3, the amount of water 11 descending within the water pipe 3 becomes unstable, and the temperature within the water pipe 3 may suddenly change by about 10°C. Further, when water supply is restarted after hot water supply is stopped, the temperature of the first header 1 decreases faster than that of the water pipe 3. Therefore, providing the temperature detector 9 inside the water pipe 3 does not allow stable temperature detection.

Purpose of the invention The present invention solves such conventional problems,
The hot water in the water pipe provided with the temperature sensor is configured to flow from the second header side to the first header, thereby keeping the temperature inside the water pipe stable and shortening the temperature detection delay.

Structure of the Invention A first header and a second header formed in an annular shape are connected by a large number of water pipes, and a water supply pipe and a hot water supply pipe are provided in the first header, and the water supply pipe passes through the inside of the first header and connects the second header with a plurality of water pipes. The tip of the water tube into which the water supply pipe is inserted and the tip of the water tube provided with the temperature sensor are connected by a U-bend, and the water supply pipe is connected to the circumferential surface facing the tip and the first header. It has a water supply opening that opens at the bottom.

With this configuration, water supplied from the water supply port opened at the tip of the water supply pipe passes through the U-bend,
The water rises while being heated inside the water tube equipped with a temperature sensor, creating a stable temperature distribution. When the water supply is restarted after the hot water supply is stopped, the water immediately cools the temperature sensor. On the other hand, water supplied from a water supply port opened on the circumferential surface of the water supply pipe rapidly mixes with hot water rising from the water pipe, and hot water is supplied from the hot water pipe.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 5 and 6. In FIGS. 5 and 6, the water supply pipe 6 passes through the first header 1, is inserted into the water pipe 3a, has its tip constricted, and has an open water supply port 8a and a water supply port opened on the circumferential surface facing the first header 1. 8b. The water pipe 3a and the water pipe 3b provided with a temperature sensor 9 are connected within the second header using a U-bend 12. Note that the same members as in FIG. 1 are given the same numbers.

In the above configuration, the water 11 supplied from the water supply port 8a rises from the tip of the water pipe 3a through the U-bend 12 while being heated, and the closer it gets to the first header 1, the higher the temperature becomes. Inside the water pipe 3b, a thermally balanced temperature distribution dominated by forced convection is always formed. Since the amount of canned water in the water pipe 3b is small, the temperature fluctuations during intermittent operation of the burner 10 are large and severe, so that the temperature detection by the temperature detector 9 becomes faster. Therefore, the delay in extinguishing the burner 10 is shortened, so that local boiling does not occur in the water pipe 3 immediately after hot water supply is stopped. Water pipe 3a is water supply pipe 6
Since the canned water is inserted, the amount of water in the can is extremely small, but heat is always taken away by the water supply pipe 6 and the temperature is relatively low, so local boiling is unlikely to occur.

When the water supply is started again after the hot water supply is stopped, the water 11 immediately cools the temperature detector 9, so the temperature detection of the temperature detector 9 becomes faster and the ignition delay of the burner 10 is shortened. Therefore, the time required to obtain the set hot water supply temperature is shortened.

Effects of the Invention As described above, according to the hot water boiler of the present invention, the following effects can be obtained.

Since the water supplied is heated and rises inside the water pipe equipped with a temperature sensor, a thermally balanced temperature distribution dominated by forced convection can always be formed within the water pipe. Therefore, the delay in temperature detection due to large and severe temperature fluctuations during adiabatic operation of the burner is shortened, and local boiling can be easily prevented.

When water supply is restarted after hot water supply is stopped, the temperature sensor is immediately cooled down, so temperature detection is quick, the burner ignition delay is shortened, and the time required to obtain the set hot water supply temperature is shortened.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional hot water boiler, Figure 2 is a partial cross-sectional plan view of Figure 1, Figure 3 is a temperature distribution characteristic diagram of the hot water boiler, and Figure 4 is an enlarged view of the main parts of Figure 1. 5 is a longitudinal sectional view of a hot water boiler according to an embodiment of the present invention, and FIG. 6 is a partially sectional plan view of FIG. 5. 1...First header, 2...Second header, 3
a, 3b...Water pipe, 6...Water supply pipe, 7...Hot water supply pipe, 8a, 8b...Water inlet, 9...Temperature detector, 12...U bend.

Claims (1)

[Scope of Claims] 1. A first header and a second header formed in an annular shape are connected by a number of water pipes, and a water supply pipe and a hot water supply pipe are provided in the first header, and the water supply pipe is connected within the first header. is inserted into the water pipe, and the tip of the water tube into which the water supply pipe is inserted is connected to the tip of the water tube provided with the temperature sensor with a U-bend, and the water supply pipe is connected to the tip and the first header. A hot water boiler with a water inlet opening on the facing circumferential surface. 2. The hot water boiler according to claim 1, wherein the water supply port opened at the tip of the water supply pipe is formed to have a smaller area than the water supply port opened at the peripheral surface.