JPH0415525Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a heat exchange device that heats a working fluid using a heat exchanger having tubes, and particularly relates to a heat exchange device that heats a working fluid by using a heat exchanger having pipes. This invention relates to improvements in the structure for preventing the destruction of existing pipes.

(Prior Art) Conventionally, as shown in, for example, Japanese Patent Application Laid-open No. 52-24617, a heat exchanger consisting of a heat pipe heat receiving section is placed in the engine exhaust pipe of an automobile.
2. Description of the Related Art A heat exchange device is known in which the heat of exhaust gas is absorbed by a heat exchanger to heat a working fluid therein, and the heated working fluid is used to heat the interior of a vehicle.

In this type of heat exchange device, the heat exchanger is
Generally, it consists of a header, multiple U-shaped tubes with a curved part at the lower end and connected to the header at the upper end, and multiple fins attached to the outer surface of these U-shaped tubes. It is placed in the engine exhaust pipe in an upright position with the U-shaped pipe vertical.

(Problems to be Solved by the Invention) In the conventional heat exchange device, when water is used as the working fluid in the heat exchanger, freezing occurs at 0°C. In conventional heat exchange devices, the U-shaped tube of the heat exchanger is placed upright in the engine exhaust pipe, as described above, and no special measures are taken to prevent freeze damage, so the working fluid inside the U-shaped tube is Ice will form on the surface.

In this case, at the beginning of freezing, the frictional resistance between the ice and the inner wall of the U-shaped tube is small, so the expanded ice can escape upwards of the U-shaped tube, but as freezing progresses, the friction between the ice and the inner wall of the U-shaped tube increases. The resistance increases and the ice is unable to escape up the U-tube. Then,
There is a risk that the weakest curved part of the U-shaped tube will become deformed and eventually break.

This idea was created in view of the current situation,
It is an object of the present invention to provide a heat exchange device that can effectively prevent freeze damage of a heat exchanger even when a working fluid freezes.

[Structure of the invention] (Means for solving the problem) The present invention is a heat exchanger in which a heat exchanger is arranged in a case, and a high-temperature fluid is introduced into the case to heat the working fluid in the heat exchanger. The device is characterized in that the lower end of the tube of the heat exchanger is connected to the lower end wall of the case exposed to the outside air so as to enable heat exchange, and the parts other than the lower end wall of the case have an insulated structure from the outside air. do.

(Function) In the heat exchange device according to the present invention, the lower end of the tube is connected to the part of the case housing the heat exchanger exposed to the outside air so as to be able to conduct heat. by the way,
It is clear that when the outside temperature decreases, the outer case and the heat exchanger inside the outer case are cooled down first. Since the lower end of the tube is connected to the case in a heat transferable manner, freezing of fluid such as water within the tube starts from the lower end and gradually moves upwards of the tube. Therefore, the expansion force of the ice can be released upwards of the tube, and the force applied to the inner wall of the lower end can be reduced, thereby making it possible to prevent freeze fracture.

(Example) An example of the present invention will be described below with reference to FIG.

FIG. 1 shows a vehicle heating device using a heat pipe as an example of a heat exchange device according to the present invention, and in the figure, reference numeral 1 indicates an exhaust pipe for discharging combustion exhaust gas 3 from an engine 2. A case 5 is provided in the middle of the exhaust pipe 1 to house a heat receiving part 4 of a heat pipe as a heat exchanger.

The heat receiving part 4 includes a header 4a, a pair of rising straight pipe parts 7a and 7b which have a curved part 6 at the lower end and stand up in parallel from the curved part 6, and the upper ends of which are connected to the header 4a. It is composed of a large number of fins 4c attached at right angles to the rising straight pipe parts 7a and 7b of the U-shaped pipe 4b, and this heat receiving part 4
is arranged in the case 5 in an inclined state such that one rising straight pipe part 7a is on the top and the other rising straight pipe part 7b is on the bottom, and the outer surface of the curved part 6 of the U-shaped pipe 4b is arranged inside the case 5. The lower end wall of the case 5 is connected to the outer surface of the case 5 so as to be able to conduct heat by contacting the inner surface of the portion exposed to the outside air. The water or other working fluid sealed in the heat pipe exchanges heat with the exhaust gas 3 led from the engine 2 into the case 5 and evaporates.

Further, the portion of the case 5 other than the portion in contact with the curved portion 6 of the U-shaped tube 4b has a double structure, and is insulated by a heat insulating material 8 disposed inside the double structure.

On the other hand, a heat dissipating section 11 of a heat pipe having heat exchange fins is inserted into an air duct 10 that supplies heating air to the vehicle interior (not shown) by a fan 9, and the heat taken in by the heat receiving section 4 is ,
The working fluid is guided to the heat radiating section 11 through a working fluid pipe 12 of a heat pipe that connects the heat receiving section 4 and the heat radiating section 11 . The working fluid condensed by heat radiation in the heat radiation section 11 flows down along the inner circumferential wall of the working fluid pipe 12 and is returned to the heat receiving section 4. The working fluid pipe 12 of the heat pipe has a heat insulating structure with a heat insulating material 13 disposed on its outer surface.

Next, the operation of this embodiment will be explained.

Inside the case 5, exhaust gas 3 from the engine 2 is stored.
is guided through the exhaust pipe 1, and the heat receiving section 4 of the heat pipe is heated by this exhaust gas 3. Then, the working fluid in the heat receiving part 4 absorbs the heat and becomes steam, and the working fluid whose pressure is increased by becoming steam is as follows.
The working fluid is guided to the heat radiation section 11 through the axial center of the working fluid pipe 12 .

The working fluid guided to the heat radiation part 11 exchanges heat with the air flowing in the air duct 10 and condenses, and the liquefied working fluid flows into the working fluid pipe 1.
It flows down along the inner circumferential wall of 2 and returns to the heat receiving part 4.

By the way, the heat receiving portion 4 of the heat pipe is arranged in an inclined state within the case 5, and therefore, the fins 4c are inclined with respect to the flow direction of the exhaust gas 3. Therefore, compared to the case where the fins 4c are parallel to the flow direction of the exhaust gas 3, the contact with the exhaust gas 3 becomes more sufficient, and the amount of heat exchange can be increased accordingly. In addition, since the heat receiving part 4 is slanted, larger items can be placed in the same space compared to when it is placed upright. It is possible to increase the amount of heat exchange.

On the other hand, if engine 2 is stopped in the heating state,
Since the heat receiving section 4 stops absorbing heat from the exhaust gas 3, the working fluid in the heat pipe liquefies.
The liquefied working fluid is then stored in the U-shaped tube 4b of the heat receiving section 4 located at the lowest position. For this reason, when the outside temperature drops, the working fluid flows through the U-shaped tube 4b.
It will freeze inside.

By the way, when the outside temperature drops, the outer case 5 and the inner heat receiving part 4 will always start to be cooled first. The outer surface of the curved portion 6 of the U-shaped tube 4b is in contact with the inner surface of the wall portion of the case 5 exposed to the outside air and is connected to the case 5 in a heat transferable manner, so that the U-shaped tube 4b is curved. The cooling starts from the header 6 first, and the cooling gradually progresses to the header 4.
This will shift to side a. In particular, since the case 5 has a heat insulating structure in which the heat insulating material 8 is disposed in a portion other than the portion in contact with the curved portion 6, this tendency is noticeable.

If the curved portion 6 of the U-shaped tube 4b begins to be cooled first, freezing will begin to occur from the curved portion 6 and will gradually move upwards of the U-shaped tube 4b. Therefore, the expansion force of the ice can be released to the header 4 side, and the force applied to the inner wall of the curved portion 6 can be reduced to prevent freeze fracture.

In the above embodiment, the outer surface of the curved portion 6 is brought into direct contact with the inner surface of the case 5, but as shown in FIG. may be brought into contact with.

Further, in the embodiment described above, the heat receiving part 4 is arranged in the case 5 with the U-shaped tube 4b inclined.
Similar effects can be expected even when the heat receiving section 4 is installed vertically.

In addition, although the case where the heat receiving part 4 of the heat pipe is arranged as a heat exchanger in the case 5 and is heated by the exhaust gas 3 from the engine 2 has been described above, the principle of the present invention is that the heat receiving part 4 of the heat pipe is It can be applied not only to the section 4 but also to any heat exchanger, and the high temperature fluid is not limited to the exhaust gas 3. Further, the principle of the present invention can be used not only for U-shaped tubes but also for heat exchangers having headers on the upper and lower sides.

[Effect of idea]

As explained above, the present invention connects the lower end of the heat exchanger tube to the lower end wall exposed to the outside air of the case housing the heat exchanger in a heat transfer manner, and connects the other parts of the case. Since it is insulated from the outside air, freezing progresses from below to above, preventing damage to the heat exchanger due to freezing and improving reliability.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram of a heat exchange device showing one embodiment of the present invention, and FIG. 2 is a block diagram of main parts showing another embodiment of the present invention. 3...Exhaust gas, 4...Heat receiving part, 4a...Header, 4b...(U-shaped) pipe, 4c...Fin, 5...
...Case, 6...Curved portion, 8...Insulating material, 11...
...Heat radiation part, 14...Metal fitting (heat transfer material).

Claims (1)

[Claims for Utility Model Registration] 1. A heat exchanger having a tube and a plurality of fins attached to the outer surface of the tube is arranged in a case,
In this heat exchange device that heats the working fluid in the heat exchanger by introducing high-temperature fluid into the case, the lower end wall of the case is exposed to the outside air, and the other case walls have a heat insulating structure from the outside air. A heat exchange device characterized in that a lower end of the tube is connected to a lower end wall of the case in a heat exchange relationship. 2. The heat exchange device according to claim 1, wherein the lower end of the tube is in direct contact with the inner surface of the lower end wall of the case. 3. The heat exchange device according to claim 1, wherein the lower end of the tube is brought into indirect contact with the lower end wall of the case via a heat transfer material.