JPS5953453B2 - Antifreeze device for water heater - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a freezing prevention device for water heaters, and its purpose is to efficiently generate natural convection by partially heating a closed circuit to prevent damage to the water heater body due to freezing. .

Most conventional water heaters open the water drain valve after use to drain the water inside the container to prevent freezing accidents in winter, but the water draining performance is insufficient, There were many cases where the equipment was damaged due to forgetting to drain the water, and it was not sufficient to prevent freezing.

In addition, as a means of preventing freezing by draining water, use the heat of the pilot flame to heat a part of the closed loop of the water circuit inside the appliance.
There are things that prevent freezing by heat transfer through water convection,
However, in the above-mentioned means of preventing freezing by convection of water, the position of the heating part is an important factor as it is a condition for causing convection, so fins are provided on a part of the can body pipe with a pilot flame to absorb heat. In this case, the temperature rises only in the upper part of the closed circuit, and natural convection is difficult to occur.

Furthermore, even in extremely cold weather, when partially heated water circulates and dissipates heat, the heat dissipation is greatest in the heat exchanger fin pipe section, so it can be closed efficiently with a small amount of heating. In order to prevent the entire circuit from freezing, the heat capacity of each part becomes an issue, so the position of the heating part is also important from this point of view.

The present invention takes this point into particular consideration and eliminates the conventional drawbacks, and one embodiment thereof will be described below.

Figure 1 shows the water circuit and gas circuit of a water heater.
is a water controller, 2 is a heat exchanger, which is connected to the water controller 1 through a heat exchange water pipe 3 and a heat exchanger pipe 4, 5 is a water inlet, and 6 is a hot water outlet (not shown). Hot water is supplied to

In other words, the water circuit from the water outlet 5 to the hot water outlet 6 constitutes the water circuit of the appliance.

Reference numeral 7 denotes a gas circuit, which has a water pressure responsive valve 8 in the middle, and gas is supplied from a nozzle 9 to a main burner 10 disposed opposite to the bottom of the heat exchanger 2, while from the origin of the gas passage to the main burner 10. 10
A pilot conduit 12 branches off to a nearby pilot burner 11 for ignition.

Note that the water controller 1 includes a water inlet portion 5, a diaphragm 13,
A high pressure chamber 14, a low pressure chamber 16, and a high pressure chamber 1 separated by
4 and the water inlet section 5 and operates in accordance with the operation of the diaphragm 13, a venturi portion 17 that generates low pressure, and an introduction hole 18 that guides the low pressure to the low pressure chamber.
, a bypass passage 20 that bypasses the heat exchanger 2 from the high pressure chamber 14 and goes directly to the outlet 6, a bypass valve 21 provided in the middle of the passage, a spring 22 that biases the valve 21 in the closing direction, and a heat exchanger. It is comprised of a mixing part 23 where the hot water from 2 and the bypass flow are mixed, a tap water outlet 6, and the like.

Note that the bypass valve 21 is operated when the water is stopped, that is, when the diaphragm 13
When the valve is not operating, the tip is held down by the diaphragm 13, which is biased by a spring 30 provided in the low pressure chamber 15 and displaced toward the high pressure chamber 14, and the valve is slightly opened. .

The valve opening lift amount at this time is regulated by the governor 16 coming into contact with the water controller body, and is set to a very small amount. , an open-and-open path passing through the heat exchanger pipe 4 is formed.

Further, 24 is a heating unit for preventing freezing when the device is not in use, and is integrally constructed with the water controller 1, and has a heater box 26 embedded therein in which an electric heater 25 is housed.

Furthermore, 27 is the wiring that supplies electricity to the heater, and there is a heat exchanger 2 on the way.
The temperature sensing element 28 is connected in series with the temperature sensing element 28 provided near the fin pipe section.

Reference numeral 29 is an outlet section connected to a power source.

In the above configuration, when the device is in use, the pilot burner 11 is ignited by operating the manual valve or igniter provided in the gas passage (not shown), and the water opening/closing valve (not shown) is operated. When the valve is opened and water is allowed to flow through the water circuit, the water flows from the water outlet 5 of the water controller 1 through the high pressure chamber 14, through the venturi 17, and into the heat exchanger 2.

During this time, a pressure difference occurs between the water pressure in the high pressure chamber 14 and the water pressure in the low pressure chamber 15 where the low pressure generated in the venturi part 17 is guided by the low pressure introduction hole 18, and the diaphragm 13 is displaced to the low pressure side, and its operation is controlled by the control rod 19. The hydraulic response valve 8 in the gas passage is opened through the gas passage, gas is supplied to the main burner 10, ignited from the pilot burner 11 that had been combusted in advance, combustion is started, and after passing through the heat exchanger 2, the gas is supplied to the main burner 10. The heat exchanger pipe 4 then returns to the water controller 1, and the water from the bypass passage 20 and the mixing section 2
3, the hot water is mixed, and the hot water is supplied from the hot water outlet 6 to the hot water faucet.

To describe the operation of the bypass valve 21 in more detail during this time, when the water is stopped at the station, the diaphragm 13 presses the valve closing direction and the valve is in a slightly open state (the setting force of the spring 30 acting in the valve opening direction is The diaphragm 13 is greatly displaced by the flow of water toward the heat exchanger 2, so the bypass valve 21 immediately closes, but the water flows toward the heat exchanger 2. When the flow exceeds a predetermined flow rate (a flow rate that does not cause boiling), the bypass valve opens again due to the pressure difference before and after the bypass valve, and a picous flow occurs.

The valve opening state at this time is independently controlled in accordance with the flow rate state of the heat exchanger 2, regardless of the operation of the diaphragm 13.

Therefore, from the time water starts flowing until it reaches the ignition flow rate or higher, it flows through the heat exchanger passage, and then as the flow rate increases, the bypass valve 21 gradually opens and the bypass flow rate also increases.
Although it varies depending on the water pressure, in a stable state (water pressure 1 kg/cm or more), the bypass flow rate is 1 to 2 times the heat exchange flow rate.
The flow will be doubled, and hot water will be supplied at the temperature after being combined in the mixing section.

Next, we will discuss the antifreeze operation when no equipment is in use.

This can be done in the winter when freezing is likely to occur, or it can be done all the time, but by plugging the outlet 29 into a power source in advance, the electric heater 25 will detect the temperature detection element 28.
It is always in a state where it can be energized by opening and closing.

Furthermore, even when the appliance is not in use, the bypass valve 23 remains slightly open as described above, and the water circuit within the appliance forms a closed circuit.

In this state, if the outside temperature drops to minus temperature and the water circuit of the appliance reaches freezing temperature, the temperature sensor installed near the fin pipe part of the heat exchanger 2, which is the fastest to cool down in the water circuit inside the appliance, detects the temperature. The element 28 is set in advance to be near the pre-freezing temperature, and when it operates at about that temperature, the circuit is energized and the heater 25 provided in the heating section 24 of the water controller begins to heat up.

At this time, the entire inside of the water circuit is in a state close to zero, but when the temperature of the water in the heating section 24 rises due to heating by the heater 25 and reaches a certain temperature or higher, the water in the upper part of the water circuit is cold, so the temperature rises. Due to the difference in specific gravity, natural convection occurs within the water circuit due to convection phenomena.

At this time, the water in the heating section 24 is heated at first, but then convection occurs and the temperature of the water in the metal body of the water controller 1 rises, and then the heat exchange water pipe 3, the heat exchanger 2, and the heat exchanger pipe It is heated by convection in the order of 4, and finally reaches a low temperature just before the heating section 24 and enters the heating section 24, where it is warmed again and the temperature rises to repeat the circulation.

This natural circulation prevents the water circuit from freezing, and this is due to both the effect of the temperature increase of the water and the effect of the flow caused by the water circulation.

The amount of heating to prevent freezing, that is, the capacity of the electric heater 25, varies depending on the outside temperature, the size of the appliance, and the capacity, but is approximately 8.
The minimum antifreeze heater capacity for a water heater equivalent to a size 10 at an outside temperature of -16°C is only 100W, and it is easy to control the heater capacity according to the rise in outside temperature, ensuring efficient freezing at all times. Prevention is possible.

Furthermore, since the cold temperature varies depending on the region, it is easy to set the heater capacity for each region.

Regarding the heater heating section, this embodiment shows one that heats the water controller 1, but even if the heating section is separated and provided in another part of the water circuit, or the heating section is distributed, As long as the conditions allow natural circulation, no matter how the heating section is installed, it will have an anti-freezing effect.

Furthermore, although an electric heater is used as the heating means, it is clear that the anti-freezing effect will be the same with heating by gas combustion heat equivalent to the pilot fire or other heat sources.

As mentioned earlier, the feature of the present invention is that it has a bypass passage structure, and even when the water is stopped, it has a bypass passage to form a closed circuit, and a part of the water circuit is heated to prevent freezing. However, the special feature is the provision of a bypass passage when the water is cut off.

The conventional bypass method (mixing method) waterway configuration uses a manual control vibrator and a cock in the bypass passage to adjust the flow rate from fully closed to fully open to control the temperature. The purpose is to obtain the maximum temperature rise when the temperature rises, and when attempting to use this conventional method to prevent freezing, it is necessary to check that the temperature control is open each time to form a closed circuit. This requires manual operation each time, which is cumbersome.

The present invention uses an automatic bypass valve system, which is a high-performance bypass system that does not require manual temperature control, and also utilizes the operation of the diaphragm to freely raise the maximum temperature mentioned above without affecting performance. Since the bypass valve can be opened when the water is cut off and a closed circuit is always provided, this anti-freezing means can be used effectively without manual operation.

It is also effective to create a simple closed circuit by providing a small hole in the bypass valve that does not significantly affect other performance (the automatic bypass valve system has superior performance compared to other systems). According to experiments, circulation is possible through small holes of φ1 to φ2).

It is clear that the effect is the same even if a small hole is provided in the conventional manual bypass valve system to prevent freezing.

As another example, as shown in FIG. 2, it is also possible to provide a flow valve within the bypass valve to form a communication hole when water is cut off.

This is 32 if there is no water flow due to the valve spring 31.
is in the open state, and when water flows (normal use state of the water heater), the ball valve 33 is in the closed state against the valve seat 34, which is the same state as a bypass valve without a communication hole.

In either case, it is very effective to use a bypass waterway configuration for the antifreeze means of the present invention.

As described above, according to the present invention, the following excellent effects can be expected.

■ Extremely effective, reliable, and efficient antifreeze by combining the bypass waterway configuration, which has a simple structural design that allows water to flow even when the bypass valve is closed, and the partially heated self-circulation antifreeze prevention method. law can be provided.

II Since it utilizes a bypass system, a waterway configuration that originally forms a closed circuit, there is no need to create a separate new waterway to form a closed circuit when water is stopped, and the structure for installing an antifreeze device is extremely simple. It's easy.

III If an electric heater is installed in the heating section, it is possible to automatically prevent freezing at any time as long as it is plugged into a power outlet, and it is also possible to prevent freezing automatically even with underground heat sources such as pilot fires without manual operation. This provides a reliable and reliable anti-freeze method that does not cause freeze-damage accidents due to forgetting to operate the conventional water draining method, etc., and is simple and does not require any troublesome operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a water heater showing an embodiment of the present invention;
FIG. 2 is a sectional view of a main part showing another embodiment. 1...Water controller, 2...Heat exchanger, 3
Heat exchange water pipe, 4...Heat exchange temperature measurement pipe, 13
...Diaphragm, 20...Bypass passage, 21...N<< non-resistance valve, 24...Heating section, 32...Communication hole, 33. ...Flow opening/closing valve (ball valve).

Claims (1)

[Claims] 1. A water controller connected to a heat exchanger, and a mixing type waterway configuration having a bypass passage that bypasses the heat exchanger from the water controller, and heats the heat exchanger. A heating section other than the burner is formed at an appropriate location in a closed circuit passing through the heat exchanger and the water controller, a bypass valve is provided in the bypass passage, and water is passed through the bypass passage even when the bypass valve is closed. A water heater antifreeze device configured to have a path. 2 Install an automatic opening/closing bypass valve in the bypass passage,
2. The antifreeze device for a water heater according to claim 1, wherein the bypass passage has a certain number of routes even when the water is cut off. 3. The antifreeze device for a water heater according to claim 2, wherein a small hole is provided in the bypass valve. 4. The antifreeze device for a water heater according to claim 2, in which a water pressure-responsive diaphragm is linked so that the bypass valve opens when the water is stopped. 5. The antifreeze device for a water heater according to claim 2, wherein a communication hole and a flow opening/closing valve are provided in the bypass valve.