JPS6022139B2 - antifreeze device - Google Patents

Description

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

Most conventional water heaters open the water drain valve after use to drain the water inside the container to prevent freezing accidents in winter, and the water coverage performance is insufficient. However, there were many cases where 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, there are some methods that use the heat of the pilot flame to heat a part of the closed loop of the water circuit configured inside the appliance, and prevent freezing by heat transfer through water convection. However, with this method, the position of the heating part is an important factor, which is a condition for convection to occur, and in reality, only the upper part of the closed circuit increases in temperature, making it difficult for natural convection 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, and from this point of view as well, the location of the heating section is important. 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. 1 is a water controller, 2 is a heat exchanger, a water supply pipe 3 connects to the water controller 1, and a hot water outlet pipe 4 leads to the water controller 1. A total injury is caused from the sprue 5 to a faucet (not shown). That is, the water circuit of the appliance is comprised from the water controller 1 to the tap water outlet 5. Further, 6 is a gas circuit, which runs from an inlet section 7 through a gas control section 8 including a manual valve and a gas governor mechanism, and a hydraulic valve 9, to a main burner 0 disposed opposite to the lower side of the heat exchanger 2; A gas path 12 for a pilot burner 11 installed nearby for igniting the main burner 10 is branched from the gas control section 8 . Note that the water controller 1 has a water inlet section 13.
, a high pressure chamber 15 and a low pressure chamber 16 partitioned by a diaphragm 14, and a governor 17 that operates in accordance with the operation of the diaphragm 14 provided between the high pressure chamber 15 and the water inlet section 13.
, an orifice 18 and a flow rate regulator 19 provided near the outlet of the high pressure chamber 15, and a low pressure introduction hole 20 downstream of the flow rate regulator 19 and the low pressure chamber 16, 21
is connected to the water supply pipe 3 at its outlet. Reference numeral 22 denotes an operating rod that transmits the operation of the diaphragm 14 to the outside, and opens and closes the hydraulically responsive valve 9.

Further, 23 is a heating part for preventing freezing when the equipment is inconvenient, and is integrated with the water controller 1.
5 is connected to the high pressure chamber 15 of the water controller 1 and the vicinity of the outlet, thus forming a closed circuit that passes through the upper heat exchanger 2 and the water controller 1 within the appliance. Note that 26 is an opening/closing cock provided in the middle of the transportation pipe 25. A heater box 28 housing an electric heater 27 is embedded in the heating section 23, and the heater 27 is fixed to the heater box 28 by a fixing plate 29.
Furthermore, the wiring for supplying electricity to the Mikawa Mahi 27 is wired in series with a temperature detection element 32 provided in contact with the fin pipe portion 31 of the heat exchanger 2 midway. 33 is an outlet section connected to a power source.

In the above configuration, when the appliance is in use, the pilot burner 11 is ignited by operating the manual valve or igniter in the gas control unit 8, and the water on/off valve (not shown) is opened to release water. When water flows through the circuit, the water flows from the water inlet 13 of the water controller 1, through the high pressure chamber 15, through the orifice 18, the flow regulator 19, and into the heat exchanger 2.

During this time, a pressure difference is created between the water pressure in the high pressure chamber 15 and the low pressure after passing through the orifice 18 and the water pressure in the low pressure chamber 16 led from the low pressure introduction hole 2, and the diaphragm 14 is displaced toward the low pressure chamber, and its operation is controlled by the operating rod 22. Hydraulically responsive valve 9 in the gas circuit via
Gas is supplied to the main burner 0 and the pre-burned pilot burner 11 ignites and starts combustion, and the water that passes through the heat exchanger 2 becomes hot water and flows from the hot water outlet 5 to the hot water faucet. Hot water is supplied. In addition, at this time, the Rentsu tube 2 that constitutes a closed circuit
The cock 26 of No. 5 is in a closed state, so that in normal use there is no flow from the water controller 1 through the lotus pipe 25 directly to the outlet. Next, we will discuss the anti-freeze operation related to this case with the equipment inconvenient.

By plugging the outlet 33 into the power source in advance during periods when freezing is likely to occur, such as in winter, the electric heater 27 can always be energized by opening and closing the temperature sensing element 32. If the opening/closing cock 26 of the lotus tube 25 is closed when the device is not inconvenient, such as at night when freezing is expected, a closed circuit is formed within the device. In this state, if the outside temperature becomes negative and the water circuit of the appliance reaches freezing temperature, the temperature sensor installed in contact with the fin pipe section 31 of the heat exchanger 2, which is the fastest to cool down in the water circuit inside the appliance, detects the temperature. The element 32 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 27 provided in the heating section 23 of the water controller 1 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 inside the heating section 23 rises due to heating by the heater 27 and reaches a certain temperature or higher, the water above the water circuit is cold, so its specific gravity decreases. The difference causes natural circulation by convection within the water open circuit.
At this time, the water in the heating section 23 is heated at first, but then convection occurs and the temperature of the entire water inside the water controller 1 rises, and then convection occurs in the water supply pipe 3, heat exchanger 2, and hot water outlet pipe 4 in that order. Finally, it reaches a low temperature just before the heating section 23, enters the heating section, is heated again in the heating section, and the temperature rises to repeat the cycle. This natural circulation prevents the water circuit from freezing, and this is due to both the effect of the increased temperature of the water and the flow effect of the water circulation. The amount of heating required to prevent freezing, that is, the capacity of the electric heater, depends on the outside temperature (room temperature if installed indoors), the number of the appliance, and the electric heater capacity.
It varies depending on the capacity (heat capacity of the entire water circuit section), and an example of the experimental results is shown in Fig. 2. Figure 2 shows the relationship between outside temperature and heater capacity (wattage) for a water heater with a capacity of 8 to 1. If freezing is prevented using these values, the temperature of the heating section will be 40 to 50.
q○, the temperature immediately before the heating section in the circulation direction is around 0°C, and the natural circulation flow rate is from several tens to 200 cc/min to prevent freezing. Next, in Fig. 3, the outside temperature -1 in the example appliance is 01 and the heater capacity is 100W.
The figure shows the temperature distribution of each part of the water circuit in the antifreeze state in the case of . As mentioned above, the temperature of the water in the heating section is 4020° C., and it is about 0.degree. C. just before the heating section, and it can be seen from FIG.

In other words, freezing can be prevented if the amount of heat absorbed in the heating section is equal to or higher than the amount of heat radiated by the water circuit due to the outside temperature, and the amount of heat radiated from the heat exchanger section has a large effect on setting the heater capacity. That will happen. Next, regarding the relationship between the position of the heating section and the ability of the antifreeze heater, in the embodiment shown in Figure 1, the heating section is provided in the water controller itself, but the heating section can be separated and the water controller can control the circulation. Even if it is installed on the upstream side, as shown in Figure 3, about 20% of the heat is radiated first in the water controller section, and then 70 to 75% is radiated in the heat exchanger section, and this situation is the same without any particular change. It has the effect of On the other hand, if the heating section is installed on the downstream side of the water controller, in the case of Figure 1, near the water supply pipe 3, due to the flow of natural circulation due to heating, the direction of circulation will be that it will first pass through the heat exchanger and pass through the water controller. will be the last one. The heat release curve in this case differs from the characteristics shown in Figure 3, and although it is not shown in the figure, the temperature of the circulating water entering the heat exchanger becomes higher, so there is no significant difference in the temperature at the point where it exits the heat exchanger. Therefore, by the time the low-temperature circulating water reaches the water controller, it no longer has the ability to warm the water controller, and with the same heater capacity as in FIG. 1, it will freeze. In particular, the water inlet 13 of the water controller is connected to piping parts that are exposed to the outside temperature, and is a non-circulating part of the circulation system, so the water controller is particularly susceptible to freezing and damage. It is a part. In order to prevent freezing including this part, follow steps 2 to 2 in the case of Figure 1. Vowel heating ability is required. In this case, efficient freezing prevention can be achieved by distributing the heating parts and setting the heater capacity in such a manner that natural circulation occurs according to the amount of heat released from each part. Therefore, the position of the heating section is very important in order to keep the heater capacity to a minimum and to perform freezing prevention with efficiency in mind. Furthermore, as mentioned above, the minimum heater capacity varies depending on the outside temperature, so it is possible to set it by region.
Once the heater capacity is set, the temperature of each part will rise as the outside temperature rises from extremely cold times. It is also easy to keep the heater capacity to the minimum level through linear control.

Furthermore, in the embodiment shown in FIG. 1, the operation for forming a closed circuit was by manual operation of the opening/closing cock 26 provided on the lotus tube 25, but by using a temperature-sensitive valve or the like, automatic opening/closing without manual operation ( closed circuit formation) is also easily possible. Alternatively, it is possible to make the inner diameter of the passage port small enough to allow natural circulation by heating (in experiments, G1 to J2 were possible), and the cock part should have a pongee hole that does not affect the performance when water is flowing through the water loom. It is also possible to eliminate manual operation by providing a closed loop configuration in which a through hole is always provided in 26. In addition, in order to ensure the safety of using electricity, the heater 27 is installed in a manner that does not make contact with the heating part metal, as shown in Figure 1, and the heater itself is made of a highly safe ceramic heater, or a power outlet is used. ' Connecting 33 to the power supply via an earth leakage breaker, etc.
Double or triple safety structures are possible. Although the heating method using an electric heater has been explained, the same effect can be obtained by directly heating the area with a pilot flame instead of using an electric heater, or by heating with another heat source.

Furthermore, although the anti-freezing effect has been described for boilers and water circuits, similar anti-freezing effects can be achieved for other equipment with water circuits, such as household well pumps.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a water heater in an embodiment of the present invention,
FIG. 2 is a diagram showing the relationship between heater capacity and outside temperature, and FIG. 3 is a temperature diagram of each part of the water circuit. 1...Water controller, 2...Heat exchanger, 2
7... Heating part (electric heater), 32...
・Temperature detection element. Figure 2 Figure 3 Figure 1

Claims (1)

[Claims] 1. A passage leading from the water inlet to the tap water outlet via the water controller and the heat exchanger, and a communication pipe connecting the water controller or its upstream side and the downstream side of the heat exchanger are provided to connect the water controller and the heat exchanger. A closed circuit passing through the water controller, a temperature sensing element that detects water temperature in the passage, and a heating section that is controlled by the temperature sensing element and provided in the closed circuit to naturally circulate water in the closed circuit. An antifreeze device consisting of.