JPS6219696A - Multitubular type heat exchanger - Google Patents

Abstract

PURPOSE:To provide a multitubular type heat exchanger in which the increase in the pressure loss is suppressed, the heat exchange efficiency is excellent with a small size,and the increase in the circulation motive power of a fluid outside a heat transfer tube is small, by interposing a plate having projections between heat transfer tubes along the tube axis of each heat transfer tube. CONSTITUTION:The heat exchanger comprises a large number of heat transfer tubes 2 disposed within a cylinder barrel 1, tubular plates 3 securing each heat transfer tube 2 to both ends of the cylindrical drum 1, and each flat plates 4 having a plurality of projections 5, inserted into adjacent heat transfer tubes 2 in the outside thereof within the cylindrical barrel 1 and in the direction of the tube axis of each heat transfer tube 2, and fixed by support members 6. A fluid flowing between the heat transfer tube 2 and the flat plate 4 is narrowed of its flowpath width by the projections 5, and the flow rate is increased at this part 10 and then returns to the original flow rate. Upon this occasion, vortexes 6 are produced and the flow is disturbed. As a result, the heat transfer amount per unit surface area of the heat transfer tube 2 becomes large and the thermal resistance thereof is decreased. Further, since these is no inversion of the flow direction, the increase in the pressure loss is suppressed to a small value compared with the heat exchanger into which is inserted a baffle plate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a shell-and-tube type multi-tube heat exchanger in which a plurality of heat transfer tubes are arranged in a body.

[Technical background of the invention and its problems] Conventionally, this kind of shell-and-tube heat exchanger, called a shell-and-tube heat exchanger, has a cylindrical body (1 ), a large number of heat transfer tubes (2) arranged in this cylindrical body (1), and a tube plate (3) that fixes the heat transfer tubes (2). The fluid (H) is made to flow inside the cylindrical body (1) outside the heat transfer tube (2), and heat exchange is performed between these two fluids through the wall of the heat transfer tube (2). Also, this type of heat exchanger tube (2)
In many cases, a baffle plate (6) is installed inside the cylindrical body (1) so that the flow of fluid flowing through the cylindrical body (1) is perpendicular to the heat transfer tubes.

In the case of such a heat exchanger with the baffle plate (6), there is a problem that pressure loss increases because the flow direction is reversed many times. In addition, the fluid passes through the gap between the inner wall of the cylindrical body (1) and the heat exchanger tube (2) group, reducing the flow rate passing through the heat exchanger tube (2) group, resulting in a reduction in heat exchange efficiency. There is.

On the other hand, when there is no baffle plate, the flow rate of the fluid outside the heat exchanger tube is generally slow and the heat exchange performance is low. Furthermore, when circular heat exchanger tubes are arranged in a body having a circular cross section, a large gap is created between the inner wall of the cylindrical body (1) and the group of heat exchanger tubes (2). Therefore, the fluid passes through the gap where it flows more easily than in the heat exchanger tube group (2), and heat exchange becomes difficult. There is also a method of attaching fins to the outer surface of the heat exchanger tube (2) to promote heat transfer, but in this case, if the outer diameter of the fin is considered as the outer diameter of the heat exchanger tube (2) without fins,
This means that the problem of the fluid passing through the gap remains unsolved.

Therefore, in the past, the heat exchanger had to be enlarged in order to obtain the desired amount of heat exchange, which required excessive power to circulate the fluid within the heat exchanger.

[Object of the invention] The present invention improves the above-mentioned drawbacks, improves the heat exchange efficiency between the fluid inside the heat exchanger tubes of a multi-tubular heat exchanger and the fluid flowing outside the heat exchanger tubes, and minimizes the increase in pressure loss. In addition, it is an object of the present invention to provide a low-cost multi-tube heat exchanger that is small in size, has good heat exchange efficiency, and has little increase in the circulation power of the fluid outside the heat exchanger tubes.

[Summary of the invention] In order to achieve the above object, the present invention distributes a medium.
In a shell-and-tube heat exchanger, in which a plurality of heat transfer tubes forming a flow path through which another medium flows is arranged in a heated outer shell, and heat exchange is performed between the two media, the plurality of heat transfer tubes are mutually connected. A plate having protrusions therebetween is interposed along the tube axis of the heat exchanger tube.

[Effects of the Invention] According to the present invention, the heat exchange efficiency between the fluid inside the heat exchanger tubes and the fluid flowing outside the heat exchanger tubes of a shell-and-tube heat exchanger is improved, an increase in pressure loss is suppressed as much as possible, and the size is reduced. This makes it possible to realize a multi-tube heat exchanger with good heat exchange efficiency and a small increase in the circulation power of the fluid flowing outside the heat transfer tubes.

[Embodiment of the Invention] A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the drawings, the same parts as in the conventional example are given the same numbers. The heat exchanger of the present invention comprises a cylindrical body (1) and a cylindrical body (1).
) A large number of heat exchanger tubes (2) are arranged in this heat exchanger tube (2).
) is fixed at both ends of the cylindrical shell (1), and between adjacent ones on the outside of the heat exchanger tubes (2) in the cylindrical shell (1), and in the tube axis direction of the heat exchanger tubes (2). inserted and supporting member (6)
A flat plate (
4). Fluid (L) is passed through the heat exchanger tube (2). Fluid (H) is inside the external cylindrical body (1)
) is passed through the heat exchanger tube (2) to perform heat exchange between the two fluids through the wall. A U-shaped notch is made on the surface of a flat plate, and this part is pushed up from the surface.

Next, the effects of the present invention will be explained with reference to FIG. The fluid flowing through the gap between the heat exchanger tube (2) and the flat plate (4) has its channel width narrowed by the protrusion (5), the flow velocity increases in this part (10), and the original Back to flow velocity. At this time, a vortex (6) is generated and the flow is disturbed. Thus, due to the increase in flow velocity and the turbulence of the flow, the temperature gradient on the outer surface of the heat exchanger tube (2) becomes very large, and as a result, the temperature gradient on the outer surface of the heat exchanger tube (2)
The amount of heat transferred per unit surface area becomes larger and the thermal resistance becomes smaller. Furthermore, since there is no reversal of the flow direction, the increase in pressure loss can be suppressed to a smaller level than in the heat exchanger in which a baffle plate is inserted.

In this embodiment, the shape of the plurality of protrusions (5) provided on the plate (4) may be cylinders extending perpendicularly from both sides of the plate, as shown in FIG. The shape may be a weight, a cone, or the like. That is, the heat exchanger tube (2
) The shape of the protrusion formed on the flat plate (4) is not limited as long as it has a shape that causes turbulence in the fluid near the surface. Further, a plurality of holes may be formed in the flat plate (4), and the holes in this case may be made of punched metal. However, flat plate (
4) The height of the protrusion (5) provided in the heat exchanger tube (2)
It is necessary to avoid contact with the

In addition, the combination of plates (4) is not limited to the first embodiment shown in FIG. 2, and may be inserted into the gaps outside the heat exchanger tubes (2) at any pitch. In this case, one plate may be bent and processed, or a plurality of plates may be joined.

However, in order for these to be held within the cylindrical body (1), they must be fixed within the cylindrical body (1) via the support member (6).

Even in a moving field, the effects of the present invention are not impaired.

[Other Embodiments of the Invention] Next, a second practical example of the invention will be described with reference to FIG.

In the second embodiment of the present invention, the plate (4) and the projection (5) in the polynomial heat exchanger in the first embodiment are made of a good thermal conductor such as aluminum, and the good thermal conductor and the heat transfer tube ( In order to increase the contact area with 2), both are welded together. In this embodiment, the flat plate (4) and the protrusion are made of a good thermal conductor such as aluminum and are welded to the heat exchanger tube (2), so there is almost no thermal resistance between them, and the flat plate (4) 4) acts as a fin and significantly increases the heat transfer area. Therefore, the reduction in thermal resistance of the heat exchanger tube (2) can be further promoted compared to the previous embodiment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a first embodiment of the present invention;
FIG. 2 shows a cross section taken along line XX in FIG. 1. A sectional view, FIG. 3 is a schematic perspective view showing the shape of the projection, and FIG. 4 is a schematic perspective view showing the shape of the protrusion.
The figure is a schematic perspective view showing the shape of the protrusion, FIG. 5 is a cross-sectional view of the main part for explaining the effects of the embodiment of the present invention, and FIG.
FIG. 7 is a sectional view showing a multi-tube growth cross section of another embodiment of the present invention. 1... Cylindrical body 2... Heat exchanger tube 4... Flat plate 5
...Protrusion Agent Patent Attorney Nori Ken Yudo Takehana Kikuo Figure 1 Figure 2 Figure 8 Figure 4 Figure 5 Figure 6 Figure 8

Claims (2)

[Claims] (1) A multi-tube heat exchanger in which a plurality of heat transfer tubes forming a flow path through which a second medium is circulated is arranged in a body through which a first medium is allowed to flow, and heat exchange is performed between the two mediums. A multi-tube heat exchanger, characterized in that a flat plate having a plurality of holes or protrusions is interposed between the plurality of heat exchanger tubes along the tube axis of the heat exchanger tubes. (2) Part or all of the flat plate is made of a good thermal conductor and is brought into contact with the heat exchanger tube.
Shell-and-tube heat exchanger described in Section 1.