JPS591933A - Method for preventing freezing of water circulating line - Google Patents

Abstract

PURPOSE:To prevent a water circulating line from freezing with an anti-freezing solution of minimum concentration, by arranging such that the anti-freezing solution has its concentration detected in conjunction with an outside air temperature and a circulation pump is caused to run in a freezing preventive manner depending on the concentration of anti-freezing solution and the outside air temperature. CONSTITUTION:A concentration detecting device 20 is provided with a positive pole 21 and a negative pole 22, and these poles are arranged to oppose to each other with a certain span in a hot water circulating line 3. The concentration is detected in an electric current flowing through an area between these poles by energizing the area with a direct current voltage V. A thermistor 16 for detecting an outside air temperature is directly connected with an electric system circuit. If there is a relationship between an electric current C and a temperature B at which a circulation pump 6 starts a freezing preventive operation such that the circulation pump 6 starts its freezing preventive operation at the temperature B slightly higher than a freezing temperature, it needs not to maintain the anti-freezing solution at such an increased concentration as is not frozen at an abnormally low temperature experienced once several years or 2-3 times a year. In this manner, a water circulating line can also suppress its development of rust.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing freezing of a water circulation system for cooling water in a heater or water-cooled equipment by circulating hot water.

Conventionally, there has been a heating device as shown in FIG. 1 as this type of device. In this figure, 1 is the boiler, 2 is the heating unit, 3 is the hot water circulation system, and 4A.

4B is an outgoing pipe and a return pipe of the hot water circulation system path 3. 5
is a stern tank, 6 is a circulation pump, T is a heat exchanger,
8 is a burner, 9 is a proportional control valve, 10 is a solenoid valve, 11 is a fuel gas inlet, 12 is a water supply port to the gas turbine tank 5, 13 is an electrical circuit, 14 is a water level detection foot R-inch, 15 is a thermistor for controlling hot water temperature, 16 is a thermistor for detecting outside temperature, 1T is a changeover switch, and 1B is a heating fan.

19 is a heat sink. Note that the electrical circuit 13 in the figure only shows a systematic one, and does not directly show the actual wiring.

With the above device, the distern tank 5-circulation pump 6
- Heat exchanger 7 - Outgoing pipe 4A - Heat radiator 19 - Return 1F 4B
→It constitutes the hot water circulation system path 3 of the di-stern tank 5, is heated by a heat exchanger T by a burner 8, and is radiated by a radiator 19 by a heating fan 18 to provide heating.

Here, the boiler 1 is generally installed outdoors, and is connected to the heating unit 2 installed indoors through an outgoing pipe 4A and a return pipe 4B, so of course some kind of anti-freezing measures are required. In this case, an antifreeze solution is used, or when no antifreeze solution is used, the circulation pump 6 is operated to prevent freezing.

When antifreeze is not used, the changeover switch IT is kept in the energized state, and when the outside temperature drops to 2 degrees Celsius, a temperature at which there is a risk of freezing, the circulation pump 6 starts anti-freezing operation using the outside temperature detection thermistor 16. It is.

When antifreeze is used, the changeover switch 1T is kept in the deactivated state K, and the concentration of the antifreeze is set to a level that will not cause freezing even at the lowest expected temperature.

Conventional heating devices are prevented from freezing as described in 5 above, and when adding antifreeze, it is necessary to make the concentration in advance so that it will not freeze even at the expected lowest temperature at the installation location. In other words, the concentration needs to be high enough not to freeze even at abnormally low temperatures, which happen once every few years. However, since antifreeze generally tends to corrode the hot water circulation system 3, it is preferable to keep the concentration to the minimum necessary level. However, it is not a good idea to frequently operate the circulation pump 6 to prevent freezing without using antifreeze in a cold region. However, the above-mentioned conventional devices have five drawbacks that are contradictory to each other.

This invention was made in order to eliminate the above-mentioned drawbacks, and detects the antifreeze concentration and outside temperature, and operates the circulation pump to prevent freezing according to the antifreeze concentration and outside temperature, thereby reducing the antifreeze concentration to the minimum necessary level. The purpose of the present invention is to provide a method for preventing freezing of a water circulation system.

This invention will be explained below.

FIG. 2 shows an embodiment of the present invention.

In this figure, 20 is a concentration detection device.

Specifically, the structure is as shown in FIG. The concentration detection device 20 has a positive electrode 21 and a negative electrode 22 facing each other at a constant interval in the hot water circulation system path 3. A DC voltage V is applied between these electrodes and the current value flowing there is replaced for detection. be. In addition, in Fig. 2, thermistor 1 for detecting outside temperature
'6 is directly connected to the electrical system circuit 13, and the other parts are connected to the first
Since it is the same as the conventional one shown in the figure, it is indicated by the same reference numeral.

Next, the operation will be explained.

FIG. 4 schematically shows the relationship between the antifreeze concentration and freezing temperature, and FIG. 5 schematically shows the relationship between the antifreeze concentration and the current value in the concentration detection device 20. Therefore, for the entire system, the relationship between the current value and the start temperature of the antifreeze operation of the circulation pump 6 is set as shown in FIG.

That is, if the antifreeze concentration is a certain value A, then the freezing temperature is B and the current value is C. The system as a whole is set to 5 so that the circulation pump 6 starts anti-freezing operation when the outside temperature drops to a temperature B' slightly higher than the freezing temperature B. For example, in a certain region, the outside temperature frequently drops by 5°C, drops to -10°C two to three times a year, and further drops to -15°C once every few years. Suppose there is a degree. In this case, if the antifreeze concentration is set to a level that does not freeze at -5°C, the circulation pump 6 will prevent freezing when the outside temperature drops further below -5°C and reaches temperature B', which is slightly higher than freezing temperature B. If you keep it running properly, you can reduce the antifreeze concentration A by 2-3 times a year.
There is no need to take into account abnormally low temperatures that occur once every few years.

In the above embodiment, the antifreeze concentration is detected by replacing it with the current value of the concentration detection device 20, but any other method may be used as long as the antifreeze concentration can be detected as a certain change lid. (ゝO) Also, in the above embodiment, the case of hot water circulation system line 3 of a heating device was explained, but it can also be used to prevent freezing of the water circulation system line of cooling water of water-cooled equipment. Also, the same effect as the above embodiment is achieved.

As explained above, this invention detects the antifreeze concentration and outside temperature, and operates the circulation pump to prevent freezing depending on the antifreeze concentration and outside temperature. Since there is no need to maintain a high antifreeze immersion level that will not freeze even at extremely low temperatures, the concentration of antifreeze can be kept to the minimum necessary, and the amount of antifreeze used can be reduced.
Furthermore, it has the advantage of suppressing corrosion of the water circulation system.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional heating device, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 3 is a schematic configuration diagram showing the concentration detection device of FIG. 2, and FIG. 4 is a diagram showing the relationship between antifreeze concentration and freezing temperature, Figure 5 is a diagram showing the relationship between antifreeze concentration and current value of the concentration detection device, and Figure 6 is a diagram showing the relationship between the concentration detection device current value and antifreeze operation of the circulation pump. FIG. In the figure, 1 is a boiler, 2 is a heating unit, 3 is a hot water circulation system, 6 is a circulation pump, 13 is an xi circuit, 15 is a thermistor for hot water temperature control, 16 is a thermistor for outside temperature detection, and 20 is a concentration detection device It is. Agent Makoto Kuzuno - (1 other person) Figure 3 Figure 5 Figure 4 Antifreeze price Figure 6 Current value 0=

Claims (1)

[Claims] A water circulation system characterized in that an antifreeze concentration and an outside temperature are detected in a water circulation system path of a device equipped with a circulation pump, and the antifreeze operation of the circulation pump is performed according to the antifreeze concentration and the outside temperature. How to prevent freezing.