JPS61276658A - Heat exchanger - Google Patents

Abstract

PURPOSE:To provide a heat exchanger which is compact in size, simple in construction, high in thermal efficiency and withstandable against burning without water by disposing a cylindrical honey-comb structure made of ceramics in a combustion gas passage, fitting a liquid tube in the inside of said passage and disposing a burner adjacent to one end side of the honey-comb structure. CONSTITUTION:A heat exchanger 6 is provided with an outer cylinder 12 whose bottom part 12a is closed and whose upper end part is turned down to constitute an exhaust cylinder 7. A burner 14 is disposed at the bottom part 12a to which an outer side liquid tube 18 penetrating through the center thereof is coupled. The lower end part of an inner side liquid tube 17 is coupled to the end wall of a joint 19 connected to the lower end of the outer cylinder 12. A honey-comb structure 10 made of ceramics as a heat exchange part is disposed between the outer cylinder 12 and the outer side liquid tube 18 at the immediately upper side of the burner 14. A liquid introduced from a liquid supply port 17a passes through a passage 3 of the inner side liquid tube 17 and flows upwardly, and returns back at the part of a cap 8. Then, the liquid flows down in the inner part of the honey-comb structure 10 of the outer side liquid tube 18, heated and supplied from a feed outlet port 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger used for heating liquid.

[Conventional technology] There have been many heat exchangers such as household water heaters and water heaters, but the fins necessary for heat exchange are made of materials with relatively poor heat resistance, such as aluminum and copper. There were many. Therefore, if the temperature of the high-temperature side of the heat exchanger, that is, the part in contact with combustion gas, especially the part adjacent to the combustor, is made relatively low, the heat exchange area must be increased accordingly, and this increases the overall heat exchanger area. This led to an increase in size.

In order to lower the temperature near the combustor, for example,
As disclosed in Japanese Patent No. 5-417265, a method has been proposed in which a part of the combustion gas that has passed through the heat exchanger is recirculated toward the combustor, mixed with new combustion gas, and sent back to the heat exchanger. However, there is a limit to the temperature drop of the combustion gas.

Unfortunately, if combustion gas was supplied to the heat exchanger without any liquid in it, the welded parts of the heat exchanger would melt and become damaged.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a heat exchanger which is compact in its entirety, has a simple configuration, has high thermal efficiency, and can withstand dry heating.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a cylindrical honeycomb structure made of ceramics is disposed in a combustion gas passage, and a liquid pipe is provided inside the honeycomb structure. A combustor is disposed adjacent to one end of the honeycomb structure.

[Operation] High-temperature combustion gas from the combustor 14 is supplied to the honeycomb structure 2, passes between the fins, and is discharged from the exhaust pipe 7 to the outside. The liquid introduced from the liquid supply port 17a flows upward through the passage 3 of the inner liquid pipe 17, is turned back at the cap 8, and is heated as it flows down inside the honeycomb structure 10 of the outer liquid pipe 18.

The hot water is supplied to the outside from the hot water supply port 15. Since the honeycomb structure 2 has excellent heat resistance, the combustor can be placed close to one end of the structure to the point where the flame temperature reaches its maximum, making it possible to improve thermal efficiency and downsize the heat exchanger. becomes.

[Examples of the Invention] The present invention will be described based on Examples. As shown in FIG. 1.2, the heat exchanger 6 according to the present invention includes an outer cylinder 12 with a closed bottom 12a and a narrowed upper end, forming an exhaust pipe 7. A combustion chamber 20 is formed at the bottom of this outer cylinder 12 . A plurality of intake ports 13 are provided at the lower end of the outer cylinder 12 at intervals in the circumferential direction, and a combustor 14 is provided at the bottom 12a. The combustor 14 has a fuel tank connected to a fuel pipe 16 that protrudes from the outer cylinder 12 to the outside.

An outer liquid pipe 1 is inserted through the center of the bottom 12a of the outer cylinder 12.
8 are coupled together, and the upper end thereof is closed with a cap 8 made of ceramics such as silicon carbide or metal. A metallized layer is provided on the inner surface of the cap 8, or a metal sealing member is interposed therein to form a sealing layer 9, and the cap 8 is coupled to the outer liquid pipe 18 in a liquid-tight manner. Further, a joint 19 is connected to the lower end of the outer cylinder 12. The lower end portion of the inner liquid pipe 17 is integrally connected to the end wall of the joint 19. A gap is provided between the upper end of the inner liquid pipe 17 and the cap 8, while a liquid supply port 1 is provided at the lower end to connect, for example, a water pipe.
7a is configured. In addition, Ia dipping port 1 is attached to the peripheral wall of the joint 19.
5 is provided, to which a conduit can be connected as necessary.

According to the present invention, in order to protect the outer liquid pipe 18 surrounded by the combustor 14 from high temperatures, a ceramic material is provided as a heat exchanger between the outer cylinder 12 and the outer liquid pipe 18 immediately above the combustor 14. A two-cam structure 2 is housed therein.

It is desirable that the honeycomb structure 2 is fitted to the inner circumferential surface of the outer cylinder 12 via a suitable heat insulating material. Similarly, the outer liquid pipe 18
A honeycomb structure 10 made of ceramics is also disposed between the inner liquid pipe 17 and the inner liquid pipe 17 .

As shown in the second factor, the heat exchange section is composed of a honeycomb structure 10.2 provided with fins, and forms a passage through which liquid passes and a passage through which hot combustion gas passes. In other words, both are cylindrical partitions that are less than half the outer diameter of the heat exchanger, that is, the outer liquid is made of ceramic or a heat-resistant metal such as stainless steel! ! It is partitioned by 18. A combustor 14 that uses gaseous fuel or liquid fuel as fuel is arranged close to one end side, ie, the lower end side, of the honeycomb structure 2 .

By configuring the present invention as described above, it is possible to provide a small heat exchanger, specifically, a water heater, with the outer diameter of the outer cylinder 12 being 100 mm + 1 length of 200 wua, for example. The fins of the honeycomb structures 2 and 10 are 0.5 to 1, h++a
The distance between the fins is 1.5 to 2.5n.
It is said that

Next, the operation of the heat exchanger according to the present invention will be explained.

High-temperature combustion gas from the combustor 14 is supplied to the honeycomb structure 2, passes between the fins, and is discharged from the exhaust pipe 7 to the outside. On the other hand, the liquid introduced from the liquid supply port 17a of the joint 19 flows upward through the passage 3 of the inner liquid pipe 17, is turned back at the cap 8, and flows inside the honeycomb structure 10 of the outer liquid pipe 18. Flow down. The liquid is heated while passing between the fins in the honeycomb structure 10, and is supplied to the outside from the hot water supply port 15.

By the way, in conventional instantaneous water heaters, the heat exchanger fins are made of aluminum, stainless steel, copper, iron, etc., so there is always a risk that the part adjacent to the combustor may be fused. The gas is mixed with air and cooled to some extent before being introduced into the heat exchanger. In such a conventional configuration, it is necessary to increase the heat transfer area by an amount corresponding to the decrease in the temperature of the combustion gas, resulting in a large size.

According to the present invention, if the fuel/air mixture ratio is set in advance so that the fuel is completely combusted and the fuel is supplied to the combustor 14, the combustor 14 can be arranged sufficiently close to the heat exchange section. In this case, even if the combustion state deteriorates slightly, fresh air is supplied from the intake port 13, and incomplete combustion can be prevented.

A sealing layer 9 made of metallized silicon carbide or a metal seal press-fitted in the middle is provided between the cap 8 and the outer liquid tube 18 at a portion where the liquid is folded back from the inner liquid tube 17 to the outer liquid 1110. By attaching the honeycomb structure 2 to the outer peripheral surface of the outer cylinder 12 via a heat insulating material, overheating of the outer cylinder 12 can be prevented.

[Effects of the Invention] As described above, the present invention provides the honeycomb structure 2 between the outer cylinder and the outer liquid pipe, and the honeycomb structure 10 made of ceramics between the outer liquid pipe and the inner liquid pipe. Since the honeycomb structure is simple and easy to make with a membrane, and the honeycomb structure has excellent heat resistance, the combustor is placed close to one end of the honeycomb structure to the point where the flame temperature is the highest. This helps improve thermal efficiency and downsize heat exchangers.

The liquid pipe is surrounded by a honeycomb structure, and the flame and combustion gas from the combustor pass through the honeycomb structure to heat the liquid pipe at an appropriate temperature, and the liquid flowing through this liquid pipe is heated, so that the combustor is heated. The parts with high flame temperatures do not directly touch the liquid pipes, which prevents overheating damage to the outer liquid pipes even in the case of dry cooking.

Since the honeycomb structure is kept at a high temperature by the flame of the combustor, complete combustion of the fuel is achieved, and the temperature of the combustion gas is sufficiently reduced before it is sent through the honeycomb structure and concentrated to the exhaust stack, making it safe. It is. Furthermore, since the heat exchanger can be made smaller, the exhaust pipe can also be made smaller, making it easier to discharge exhaust gas outdoors, which is also effective in terms of safety.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a heat exchanger according to the present invention, and FIG. 2 is a plan sectional view thereof. 2.10: Honeycomb structure 7: Exhaust pipe 12: Outer pipe
14: Combustor 16: Fuel pipe 17: Inner liquid! ! i
s: Outer liquid pipe

Claims (1)

[Claims] A cylindrical honeycomb structure made of ceramics is arranged in a combustion gas passage, a liquid pipe is fitted inside the honeycomb structure, and a combustor is arranged adjacent to one end side of the honeycomb structure. A heat exchanger featuring: