JPS601556B2 - Heat exchanger antifreeze device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antifreeze device for a heat exchanger in which water or hot water is passed through water pipes.

In equipment that exchanges heat by flowing water through the pipes of fin-tube heat exchangers, such as water-cooled condensing clothes dryers and hot water heaters, it is necessary to drain the water inside the pipes in winter or in cold regions to prevent the water from freezing. There is.

This conventional method of draining water will be explained with reference to the drawings.

Figure 1 shows the flow of cooling water, where 1 is a heat exchanger, water supplied from water supply pipe 2 passes through water pipe 3, and drain pipe 4.
more excreted. In order to drain the water remaining in the heat exchanger after use, a drain cock 5 is provided at the bottom of the heat exchanger to perform the water draining operation, but it is necessary to provide a drain pipe 6 to drain the drained water. There is. In addition, in the case where a drain pipe is not provided, it is necessary to provide a drain port 7 to receive and dispose of the waste in a container 8, which is troublesome. Furthermore, in a heat exchanger where the water pipes 3 meander as shown in Fig. 1, it is difficult to completely drain the water inside the heat exchanger even if the water is drained as described above. There was a risk that water would remain and freeze, resulting in no cooling water flow, rendering the system inoperable, or damaging the water pipes. For this reason, a heat exchanger with headers 9 provided at both ends of the water tube as shown in Figure 2 is used to make it easier to drain water, but the water tube also needs to be thicker, making the heat exchanger large and expensive. There were many problems such as low heat exchange efficiency. The present invention improves these problems and provides an antifreeze device that uses a small, high-performance, and inexpensive heat exchanger and is easy to operate. Examples thereof will be described below with reference to the drawings.

FIG. 3 is a diagram showing the cooling water flow path of the heat exchanger of the present invention. In the 10G heat exchanger, the water pipe 11 is meandering and continuous 1
It forms a flow path for books.

Cooling water is supplied from a water supply hose 13 connected to a water faucet 12, passes through a water supply pipe 14, a two-way switching valve 15, a water pipe 11 of the heat exchanger, and is discharged from a drainage hose 16. To end the operation of the equipment and perform antifreeze operations, the faucet 12 is closed to stop the water supply, the water supply hose 13 is removed from the faucet 12, and the water in the water supply hose is drained. Water in the water supply hose and water supply pipe passes through the water pipe due to the difference in head and is discharged from the drain hose. Next, the air pump 17 is operated, the two-way switching valve 15 is switched, and the piping to the heat exchanger is connected to the air supply pipe 18 side. Then, air is sent from the air pump 17 to the water pipe 11 of the heat exchanger 10 through the air pipe 18 and the two-way valve 15, and the water in the water pipe is pushed out by the air and discharged from the drain pipe 16. The water in the water pipe is replaced with air and most of the water is discharged within a short period of several seconds to several tens of seconds. However, about 10 to 20% of water remains in the water pipe. The air pump is small and the air volume is small, so the residual water will not be discharged no matter how much air is supplied. When the pump is stopped, the frozen particles collect in low places inside the water pipes, causing them to become blocked. To prevent this, if you run the air pump continuously and continue to supply air, the air passage will be secured without freezing, and even if it freezes, it will only be a part of the cross section of the water pipe, and you can operate the equipment and cool it down. It is possible to operate the water pipe without any problem, and there is no danger of the water pipe being damaged due to freezing. Next, an experimental example of the present invention will be shown.

The inner diameter of the water pipe is 9.5, the water capacity in the water pipe is 500, the power of my heat exchanger, and the amount of air supplied as an air pump is 1.5 t/min.
, power consumption of 3.5 W was used. The wind speed inside the pipe at this time is about 0.36 degrees/sec, and most of the water is discharged in about 2 seconds after the air is blown, leaving about 60 degrees of water remaining in the pipe.
Met. Even if the air pump is operated continuously thereafter, water will not be discharged any more, but even if the pipe freezes, only a portion of the cross section of the pipe is frozen, and the passage of water is ensured. As described above, according to the present invention, even a small heat exchanger with meandering thin water pipes, which was difficult to drain in the past, can be used, and there is no need to use a drain pipe or a container to receive water.

Furthermore, since it is small, has a small air volume, and can be used with an air pump, small and inexpensive devices such as those used for breeding tropical fish can be used, so it has great effects such as being able to prevent freezing at low cost. FIG. 4 is an example of an electric circuit according to an embodiment of the second invention.

19 is the load on the equipment, such as dryer fan, dryer,
Such as a heater. 21 is the power supply switch for the equipment.

17 is an air pump, and 22 is an air pump operation switch.

Now, as shown in FIG.
If the air pump is operated in conjunction with the operation of the two-way switching valve by the operation in step 3, then by switching the two-way switching valve to the air supply side (drainage), the air pump will operate and air will flow into the heat exchanger water pipe. sent. In this way, the antifreeze operation can be completed simply by operating the two-way switching valve, which provides excellent operability. FIG. 6 is an electrical circuit diagram of the third and fourth embodiments of the invention.

Reference numeral 19 indicates a load on the equipment, such as a dryer's motor, heater, etc.

21 is a power source.

Reference numeral 24 indicates a device control switch, such as a manual switch or a timer.

25 is an electromagnetic switching valve which operates in conjunction with the operation of the equipment, and is used in place of the two-way switching valve shown in FIG. 3, 15.

17 is an air pump, and 26 is a thermoswitch that closes when the temperature becomes low enough to cause freezing (usually around 0 to 4 degrees Celsius). To explain its operation, the equipment control switch 24 is operated, the equipment load 19 is operated, and at the same time the electromagnetic cut-off valve 25 is operated.
operates and switches to the water supply side, and cooling water is supplied. The control switch 24 switches to the air pump side and the equipment load 19
At the same time, the electromagnetic switching valve 25 operates, and the water supply from the water condensation pipe 14 is stopped, and the water supply pipe 18 and the heat exchanger water pipe 11 are stopped.
is connected. After that, when the ambient temperature drops below a temperature that may cause freezing, the thermoswitch 26 closes and the air pump 17 is operated to supply air to the heat exchanger water pipe 11, causing the inside of the pipe to freeze, causing the entire cross section of the water pipe to freeze. prevent freezing. As described above, according to the present invention, water is not only automatically supplied and stopped by only operating the control switch 25, but also preparations for anti-freezing are automatically made after the equipment is used, so that it is possible to prevent the anti-freezing operation from being performed inadvertently. There is no longer any risk of freezing and damaging equipment because you forgot it.

In addition, since the air pump is only operated when the ambient temperature is low and there is a risk of freezing, power consumption is also reduced.

[Brief explanation of drawings]

Figures 1 and 2 are block diagrams of the conventional device, Figure 3 is a diagram showing the cooling water flow path of the embodiment of the present invention, Figure 4 is an electric circuit diagram of the second invention, and Figure 5 is An explanatory diagram of the operation of the air pump operation switch. FIG. 6 is an electric circuit diagram of the third and fourth inventions. 10・
...Heat exchanger, 11...Water pipe, 15...Two-way switching valve, 17...Air pump, 22...Air pump operation switch, 24...Equipment control switch, 25...Solenoid switching Valve, 26...Thermoswitch. O picture spear 2 picture spear 3 picture spear 4 picture spear 5 picture A 6 picture

Claims (1)

[Scope of Claims] 1. Freezing prevention for a heat exchanger that allows water or hot water to flow through water pipes, and in which air is sent into the water pipes using an air pump to forcibly discharge the water inside the pipes after use. A freeze prevention device for a heat exchanger, characterized in that an air pump drive circuit is formed in conjunction with the switching operation of a two-way switching valve that switches between a water supply path and an air supply path in the device. 2. Claim 1, characterized in that a thermoswitch is disposed in the air pump drive circuit, which closes the circuit when the ambient temperature drops to a temperature that poses a risk of freezing.
Antifreeze device for heat exchangers as described in Section 1.