JPS61190294A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve further an effect of promoting of thermal transmittance with a radiator by a method wherein the thermal transmittance pipe is surround by aeration type radiator, the heating fluid is passed between the thermal transmittance pipe and the radiator and further passed from inside of the radiator to the outside thereof. CONSTITUTION:Heating fluid HL is flowed into each of the radiators 16 surrounding a thermal transmittance pipe 11 at a substantial same temperature as that a the inlet part 18 for the heating fluid, respectively, and then flowed longitudinally along the thermal transmittance pipe 11, passed from inside of each of the portions in the radiator 16 to the outside portion and then flowed out from the heating fluid outlet port 19. In this case, the heating fluid HL is filled in an entire inner side of the radiator 11 nuder a resistance when it is passed through the radiator 16 and passed through the radiator 16, so that the flow rates of the heating fluid HL passing through each of the portions of the radiator 16 become substantially equal. since the radiator 16 is composed of a ceramic honycomb structure, it may have a wide surface area and when the heating fluid HL is passed through it, it is heated to a hot temperature. In this way, radiation heat is applied to each of the thermal transmittance pipes 11 from the hot and uniformly heated respective radiator 16, resulting in promoting a thermal transmittance under a radiation heat.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a heat exchanger having heat transfer tubes such as a tubular type or a bayonet type, and more particularly relates to a heat exchanger provided with a radiator for improving heat exchange efficiency. .

"Prior Art and its Problems" As a conventional heat exchanger, for example, one shown in FIG. 4 is known. That is, a plurality of heat exchanger tubes 32 are arranged so as to be perpendicular to the flow path 31 of the heating fluid HL, and the inside of the heat exchanger tubes 32 serves as a flow path 33 for the fluid to be heated. An air-permeable radiator 34 made of a ceramic honeycomb body or the like is arranged to partition each heat transfer tube 32 along the flow path 31 of the fluid to be heated. Therefore, the heating fluid HL flows through the radiator 34 and heats the radiator 34 to a high temperature. The radiator 34 is configured to radiate heat to the heat transfer tube 32 to increase efficiency.

However, in the conventional heat exchanger as described above, the temperature of the heating fluid HL is high on the upstream side of the heating fluid HL, and the temperature of the radiator 34 is also high, so the effect of promoting heat transfer by radiation is high. On the downstream side of the fluid HL, the heated fluid H
Since the temperature of L becomes low, the effect of promoting heat transfer by radiation is relatively reduced, and a large-scale heat exchanger may not be able to fully demonstrate its overall effect. In addition, in this heat exchanger, the radiant heat of the radiator 34 does not hit the entire outer surface of the heat transfer tube 32, and in other words, the view factor as seen from the heat transfer tube 34 is considerably smaller than 1. There were limits to its effectiveness.

"Objective of the Invention" The object of the present invention is to use a breathable radiator to irradiate almost the same amount of radiant heat to every heat exchanger tube, and
An object of the present invention is to provide a heat exchanger in which the entire outer surface of a heat exchanger tube is irradiated with radiant heat, thereby further enhancing the heat transfer promoting effect of a radiant.

"Structure of the Invention" The heat exchanger according to the present invention has a flow path for a heated fluid formed inside a heat exchanger tube, a flow path for a heated fluid formed outside, and an air-permeable area surrounding the heat exchanger tube. A radiator is disposed, and a flow path of the heating fluid passes between the heat transfer tube and the radiator, and passes from the inside of the radiator to the outside.

Therefore, the heating fluid flows almost equally from the inside of each radiator surrounding the heat transfer tube and exits to the outside, thereby heating each radiator almost equally. Moreover, since the radiator is arranged to surround the heat exchanger tube, radiant heat is applied to the entire outer surface of the heat exchanger tube. Therefore, the heat transfer promoting effect can be further enhanced.

According to a preferred embodiment of the present invention, the heat exchanger tube has a so-called tubular type or bayonet type. That is, in these types, it is generally easy to arrange the breathable radiator.

It is sufficient that the radiator is ventilated, that is, the heated fluid can pass from one side of the radiator to the other. For example, the radiator may be a foamed or non-foamed porous ceramic plate having a large number of open pores. According to a preferred embodiment,
The radiator consists of a ceramic honeycomb body. Ceramic honeycomb bodies have a large surface area, can withstand high temperatures,
The ventilation resistance is generally low, the emissivity ε is high, and more radiant heat can be generated.

According to a further preferred embodiment of the present invention, the radiators are arranged so as to surround each heat exchanger tube.

According to this, the heat transfer tube is more reliably irradiated with radiant heat, and the heat transfer promotion effect is further enhanced.

According to a further preferred embodiment of the present invention, the heat exchanger tube is made of ceramics. The effect of radiant heat from a radiator increases as the temperature of the material increases, so it is most effective to use ceramics as the heat transfer tube for high-temperature heating fluids.

``Embodiment of the Invention'' FIGS. 1 and 2 show an embodiment of the heat exchanger according to the present invention.

The ceramic heat transfer tube 11 has both ends connected to the upper and lower tube sheets 1.
2.13 is maintained. The heated fluid OL enters from the heated fluid inlet 14, passes through the heat transfer tube 11, and exits from the heated fluid outlet 15.

A radiator 1B made of a plate-shaped ceramic honeycomb body is arranged between an upper tube plate 12 and a radiator holding plate 17 so as to surround the heat transfer tube 11. A large number of cells of the ceramic honeycomb body are open on both sides of the radiator 1B, so that the radiator 16 is covered so as to allow ventilation from one side to the other side.

The heating fluid HL enters from the heating fluid inlet 18 and is heated to the heat exchanger tube 11 and the radiator 1 through the hole 17a provided in the radiator holding plate 17.
It enters the space between B, passes through the radiator 16 from the inside to the outside, and exits from the heated fluid outlet 18.

In the above heat exchanger, the heating fluid HL is heated through the heat transfer tubes 11
Inside each radiator 16 surrounding a heated fluid inlet 18
In. They each flow in at a high temperature approximately the same as i, flow along the longitudinal direction of the heat exchanger tube 11, pass through each part of the radiator 16 from the inside to the outside, and flow out from the heated fluid outlet 18. In this case, due to the resistance when passing through the radiator 16, the heating fluid (IL) once fills the entire inside of the radiator 16 and then passes through the radiator 16, so the heating fluid HL passes through each part of the radiator 18. The flow rates will be approximately equal. Since the radiator 16 is made of a ceramic honeycomb body,
It has a large surface area and is heated to a high temperature when the heating fluid HL passes through it. In this way, each heat transfer tube 11 is irradiated with radiant heat from each radiator 16 heated evenly at a high temperature, and heat transfer is promoted by the radiant heat.

FIG. 3 shows another embodiment of the heat exchanger according to the invention. In this embodiment, the heat exchanger tube 11 is of a bayonet type.

This heat exchanger tube 11 consists of an outer cylinder 21 and an inner cylinder 22.

The outer cylinder 21 is preferably made of ceramics, so that it can be applied to high-temperature heating fluids. The inner cylinder 22 is made of gold, metal, or ceramics, taking into consideration the temperature of the fluid to be heated, manufacturing cost, and the like. The outer cylinder 21 is closed at its lower end and supported at one end by the lower tube plate 13. Further, the inner cylinder 22 has an open lower end and an upper end held by the upper tube plate 12. Furthermore, the radiator 16 made of a ceramic honeycomb body includes a lower tube plate 13 and a radiator holding plate 1.
7 so as to surround the heat transfer tube 11.

The heated fluid OL flows in from the heated fluid inlet 14, flows downward between the outer cylinder 21 and the inner cylinder 22, turns around at the lower end of the outer cylinder 21, and passes through the inside of the inner cylinder 22. It flows in one direction and flows out from the heated fluid outlet 15. In addition, heating fluid HL
flows from the heating fluid inlet 18, enters the inside of each radiator 16 through the hole 17a of the radiator holding plate 17, and enters the inside of each radiator 16.
The heated fluid passes through from the inside to the outside and flows out from the heated fluid outlet 18. Also in this example.

Each radiator 16 is heated to a high temperature almost equally by the heating fluid HL, and the outer cylinder 21 of the heat transfer v11 is irradiated with radiant heat to promote heat transfer.

Note that it is preferable to adjust the ventilation resistance of the radiator 16 as necessary so that the heating fluid HL passes through each radiator 16 equally.

"Effects of the Invention" - As explained above, according to the present invention, the breathable radiator is arranged to surround the heat exchanger tube, and the flow path of the heating fluid passes between the heat exchanger tube and the radiator. Since the radiator is configured to pass from the inside to the outside, the radiator is heated to a high temperature by the heating fluid, and the radiant heat is irradiated onto the heat transfer tube. In this case, since the radiator is arranged to surround the heat exchanger tube, the entire outer surface of the heat exchanger tube is irradiated with radiant heat. Further, due to the ventilation resistance of the radiators, the heating fluid once fills the inside of each radiator and then passes through the radiators, so each radiator is heated almost equally by the heating fluid. In this way, the heat transfer coefficient can be improved by the radiant heat emitted from the radiator, and the heat exchanger can be made more compact.

To give a specific example, in a conventional shell-and-tube heat exchanger, the heat transfer coefficient outside the tube is about 20 to 30 kcal/rn'h'O, but according to the heat exchanger of the present invention, the heat transfer coefficient outside the tube is The heat transfer coefficient can be increased to about 100 to 200 kcal/rn'h'0.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the heat exchanger according to the present invention, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. Fig. 4 is a longitudinal cross-sectional view showing an embodiment of the present invention, and Fig. 4 is a cross-sectional view showing main parts of a conventional heat exchanger. In the figure, 11 is a heat exchanger tube, 12 is an upper tube sheet, 13 is a lower tube sheet, 14 is a heated fluid inlet, 15 is a heated fluid outlet, 16
is a radiator, 17 is a radiator holding plate, 18 is a heated fluid inlet,
18 is a heating fluid outlet, 21 is an outer cylinder, 22 is an inner cylinder, HL is a heating fluid, and CL is a heated fluid. "91-+ Figure 2 Figure 4

Claims (5)

[Claims] (1) In a heat exchanger in which a flow path for a heated fluid is formed inside a heat transfer tube and a flow path for a heated fluid is formed on an outside thereof, a breathable radiator is arranged so as to surround the heat transfer tube, The flow path of the heating fluid passes between the heat exchanger tube and the radiator,
A heat exchanger characterized in that the heat exchanger is configured to pass from the inside to the outside of the radiator. (2) The heat exchanger according to claim 1, wherein the heat exchanger tube is of a tubular type or a bayonet type. (3) A heat exchanger according to claim 1 or 2, wherein the radiator is a ceramic honeycomb body. (4) A heat exchanger according to any one of claims 1 to 3, wherein the radiator is arranged to surround each of the heat exchanger tubes. (5) A heat exchanger according to any one of claims 1 to 4, wherein the heat exchanger tubes are made of ceramics.