JPS6311544Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an after-boiling prevention device for water heaters. A directional valve is installed in the bypass pipe installed between the water supply pipe and the hot water outlet pipe, which closes when the hot water is being used and opens when the hot water is stopped. To provide an after-boiling prevention device for a water heater that can be used safely and economically at all times by preventing after-boiling when the water heater stops dispensing water.

Conventionally, as seen in Japanese Utility Model Application Publication No. 54-165834, a system in which high-temperature hot water is circulated using a pump is expensive to manufacture and is difficult to put into practical use. In addition, the one disclosed in Japanese Utility Model Application Publication No. 54-165834 has a cylinder with a large capacity installed in the bypass pipe connected between the water supply pipe and the hot water outlet pipe, and the differential pressure generated in the cylinder before and after the heat exchanger is A sliding piston and a spring that constantly presses the piston in the direction of the water supply pipe are inserted, and when hot water is used, the differential pressure generated before and after the heat exchanger causes the piston to move against the spring toward the hot water pipe. The water is guided and stored in the cylinder on the water supply side, and when hot water is stopped, the differential pressure in the heat exchanger disappears and the piston is pressed by the spring and moves, that is, it slides toward the water supply pipe and the water inside the cylinder This system pushes out the accumulated water on the water supply side of the piston, sucks in the high-temperature water in the heat exchanger, and introduces it into the bypass passage to prevent after-boiling due to residual heat, but the cylinder volume needs to be considerably large and is difficult to manufacture. It is difficult and the product is expensive.

This invention is intended to correct such drawbacks and achieve the intended purpose, and one embodiment of the invention will be described below with reference to the drawings.

In the drawing, 1 is a water supply pipe, 2 is a hot water outlet pipe, 3 is a bypass pipe connected approximately horizontally between the water supply pipe 1 and the hot water outlet pipe 2, A is a heat exchanger disposed below the bypass pipe 3, V is a directional valve installed in the middle of the bypass pipe 3, and a valve 6 installed opposite to the valve seat 5 in the valve housing 4 is inserted between the end of the valve housing 4 on the outlet pipe 2 side. The configuration is such that spring 7 biases the valve in the opening direction.
When hot water is used, the valve 6 is pressed against the valve seat 5 against the spring 7 by the pressure difference P1-P2 between the high-temperature hot water and the water pressure P1, P2 (P1>P2) caused by the pressure loss due to the water flow inside the heat exchanger A. to close the valve, and when the hot water supply is stopped, the pressure difference P1-
When P2 becomes 0, the pressing force of the spring 7 moves the valve 6 away from the valve seat 5 and opens the water supply pipe 1 and the hot water tap 2 through the bypass pipe 3. In addition, 8 is a blinker installed in the water supply channel, 9 is a combustion tube (inner shell), and 10 is a gas burner.

However, when using hot water, heat exchanger A using water flow
Pressure P1 generated before and after heat exchanger A due to pressure loss inside
Due to the pressure difference P1-P2 of P2 (P1>P2), the valve 6 is pressed against the valve seat 5 against the spring 7, and the valve is closed. It is introduced into exchanger A and can perform normal hot water supply. Next, when the hot water tap is stopped, the pressure difference P1-P2 becomes 0, and the pressing force of the spring 7 moves the valve 6 away from the valve seat 5 and opens the water supply pipe 1 and the hot water tap pipe 2 through the bypass pipe 3. let Therefore, the high-temperature hot water stored in the heat exchanger A has a low specific gravity, so it rises and reaches the outlet pipe 2 side of the bypass pipe 3, and the low-temperature water supply has a higher specific gravity, so it descends. It tends to reach the inlet side of heat exchanger A at the bottom, and also from heat exchanger A → outlet pipe 2 → bypass pipe 3
Since a closed distribution path is formed: outlet pipe 2 side → directional valve V → water supply pipe 1 side of bypass pipe 3 → water supply pipe 1 → heat exchanger A, high-temperature hot water is placed at the top of this distribution route, that is, Since the hot water circulates and convects in the bypass pipe 3 and the valve housing 4 and is stored, the hot water does not stagnate in the heat exchanger A. Therefore, the residual heat will not cause the water to heat up and become (over)hot water, and after-boiling is prevented. In the embodiment shown in FIG. 2, the pipe on the outlet pipe 2 side of the bypass pipe 3 is made as short as possible to reduce the volume of the pipe as much as possible, and the water supply pipe is connected to the bypass pipe 3 on the water supply pipe 1 side. The upstream piping 1' of the water supply pipe 1 is connected as close as possible to the valve housing 4, and the upper part of the water supply pipe 1 is formed as a horizontal part at approximately the same level as the valve housing 4. After the hot water tap stops, most of the hot water circulates and accumulates in the valve housing 4 and the horizontal section of the water supply pipe 1, where it mixes with the low-temperature supply water, and when hot water is tapped, the temperature drops considerably due to the mixing of the supply water, so intermittent operation is performed. Even if this is repeated many times, there is an effect of completely preventing the danger of the high temperature hot water accumulating from the outlet pipe 2 to the valve casing 4 flowing back into the heat exchanger A and becoming hot water.

If the pipe 1' on the upstream side of the water supply pipe 1 is made to have a slightly smaller diameter than the horizontal part and protrude slightly along the horizontal part, the mixing of the supply water will be promoted as a jet jet, and the temperature of the hot water will decrease more greatly. In good condition. Although the example in which the bypass path 3 is connected to the inlet and outlet of the heat exchanger A is shown above, it may be connected to the upstream side of the flasher 8 instead of the inlet side of the heat exchanger A, and in that case, the A large pressure difference can be achieved.

In Fig. 5, a small hole 6a is bored in the valve 6, so that some water flows into the bypass path 3 even when hot water is tapped, and when hot water stops pouring, some of the high-temperature hot water that accumulates flows directly into the hot water tap 2 and mixes with low-temperature water. Therefore, there is an effect of preventing hot water from being discharged at a low temperature that occurs when re-dispensing hot water.

As explained above, this idea is based on the bypass pipe installed approximately horizontally between the water supply pipe and the hot water tap.When hot water is in use, the valve is closed by the pressure difference generated before and after the heat exchanger due to the water flow, and when the hot water tap is stopped, the valve is closed by the pressure difference. It has a simple structure with a directional valve that opens when the water reaches 0, and the flow of hot water is not obstructed in any way, preventing after-boiling due to residual heat when dispensing water is stopped, so hot water is discharged by after-boiling. This has the advantage that there is no such danger, and since the structure is extremely simple, it can be provided at low cost.

[Brief explanation of drawings]

Figures 1 and 2 are general views showing two different embodiments of this invention, Figures 3 and 4 are sectional views showing the open and closed states of the directional valve, and Figure 5 is another embodiment of the directional valve. It is a sectional view showing an example. 1... Water supply pipe, 2... Hot water outlet pipe, 3... Bypass pipe, A
...heat exchanger, V...directional valve, 6...valve, 6a...pore.

Claims (1)

[Scope of utility model registration request] A bypass pipe 3 is connected to the upper part of the heat exchanger A between the water supply pipe 1 and the hot water outlet pipe 2 to provide a circulation convection path. An after-boiling prevention device for a water heater, characterized in that it is provided with a directional valve V which closes and opens by the urging force of a spring when the pressure difference becomes zero when hot water is stopped.