JPS6222996A - Multi-tubular heat exchanger - Google Patents

Abstract

PURPOSE:To promote heat exchanging efficiency between a fluid inside a heat exchanger tube of a multi-tubular heat exchanger and a fluid flowing outside said heat exchanger tube to restrain pressure drop from becoming larger, by inserting a spiral plate in an axial direction of tube into a gap existing outside a heat exchanger tube within an outer shell. CONSTITUTION:The heat exchanger comprises tube plates 3 for securing heat exchanger tubes 2 thereto and a plurality of spiral plates 4 inserted in an axial direction of said heat exchanger tubes 2 into the space existing between the outside of a plurality of heat exchanger tubes 2 and the inside surface of a cylindrical shell 1. By the presence of the spiral plates 4 being inserted, rotational motion of fluid occurs, causing agitation therein, so that the temperature distribution of the fluid approaches to uniformized one, resulting in an abrupt change in the temperature of the fluid near the heat exchanger tubes 2, leading to a very large temperature gradient, heat flow per unit surface of the heat exchanger tubes 2 becoming large and surface resistance thereof becoming low. Furthermore, since reversion in the flow direction does not occur, increment in pressure loss can be limited to a small amount.

Description

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

[Technical background of the invention and its problems and points]

Conventionally, this type of shell-and-tube heat exchanger, called a shell-and-tave heat exchanger, has the following characteristics, as shown in FIGS. 6 and 7.
A cylindrical body (1), a large number of heat exchanger tubes (2) arranged in this cylindrical body (1), and a tube plate (1) that fixes the heat exchanger tubes (2).
3), the fluid (L) is passed through the heat exchanger tube (2), the fluid (force) is circulated in the cylindrical body outside the heat exchanger tube (2), and the fluid (L) is passed through the wall of the heat exchanger tube (2), and the two Heat exchange is performed between fluids. Also, in this type of heat exchanger, the transmission tube (2) and the cylindrical body (
1), in many cases a baffle plate (6) is installed so that the flow of fluid flowing within the cylindrical body (1) is perpendicular to the heat transfer tubes (2). Said baffle board (6
), the flow direction is reversed many times, so
There is a problem that pressure loss becomes large. Also, - cylindrical body (1
) There is a problem that the fluid passes through the gap between the inner wall and the heat transfer tube (2) group, and the flow rate passing through the heat transfer tube (2) group decreases, resulting in a decrease in heat exchange efficiency.

On the other hand, if there is no baffle plate, a large gap will generally be formed between the heat exchanger tubes (2), the inner wall of the cylindrical body (1), and the group of heat exchanger tubes (2). Therefore, the fluid is the heat transfer tube (2)
# # passes through the gap where it flows easily, making it difficult for heat exchange to take place. There is also a method of attaching fins to the outer surface of the heat transfer tube (2) to promote heat transfer, but in this case, the outer diameter of the fin is set to
) Considering the outer diameter, 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.

[Purpose of the invention]

The present invention improves the above-mentioned drawbacks, improves the heat exchange efficiency between the fluid inside the heat exchanger tube of a multi-tube heat exchanger and the fluid flowing outside the heat exchanger tube, suppresses the increase in pressure loss as much as possible, and heats the heat exchanger in a small size. The purpose of the present invention is to provide a low-cost multi-tube heat exchanger with good exchange efficiency and little increase in circulation power of fluid outside the heat transfer tubes.

[Summary of the invention]

The present invention has been made to achieve the above object, and the present invention includes:
A multi-tube heat exchanger consisting of a plurality of heat exchanger tubes and an outer shell that houses the heat exchanger tubes, in which a twisted plate, for example, is inserted in the tube axial direction into a gap outside the heat exchanger tubes in the outer shell. .

〔Effect of the invention〕

According to the present invention, the heat exchange efficiency between the fluid inside the heat exchanger tube and the fluid flowing outside the heat exchanger tube of a multiple-9 type heat exchanger is improved,
It is possible to realize a multi-tubular heat exchanger that is small, has good heat exchange efficiency, and has a small increase in the circulation power of the fluid flowing outside the heat transfer tubes by suppressing the increase in pressure loss as much as possible.

[Embodiments of the invention]

A first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a sectional view taken along the line XX@ of FIG. 1. In the drawings, the same parts as in the conventional example are given the same numbers. The heat exchanger of the present invention includes a cylindrical body (1), a large number of heat transfer tubes (2) disposed inside the cylindrical body (1), a tube plate (3) for fixing heat transfer W (2), and a plurality of It consists of a plurality of twisted plates (4) inserted in the direction of the tube axis of the heat exchanger tube (2) into the gap between the outside of the heat exchanger tube (2) and the inside of the cylindrical body (1). Both ends of the twisted plate (4) are
It is fixed to the tube plate (3), and the torsion plate (4) is fixed to the third tube plate (3).
As shown in the figure, a thin and thin plate is twisted many times to create a thin shape. The width of the twist plate and the twist pitch are determined by the size of the gap, the flow rate of the fluid outside the heat exchanger tube (2), and the like.

Next, the present invention will be explained in detail. By inserting the twisted plate (4), a swirling flow is generated in the fluid flowing inside the cylindrical body (1), and the flow of the fluid outside the heat transfer tube (2) is disturbed and stirred, thereby changing the fluid temperature distribution. The temperature of the fluid approaches uniformity, and the temperature of the fluid changes rapidly near the heat transfer tube (2). That is, if the temperature gradient of the fluid on the outer surface of the heat exchanger tube (2) is very large, the amount of heat transferred per unit surface area of the heat exchanger tube (2) becomes large and the thermal resistance decreases. Since there is no reversal of the old curve, the increase in pressure loss can be suppressed to a smaller extent than in the heat exchanger in which the baffle plate is inserted.

[Other embodiments of the invention]

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. The heat exchanger of this embodiment is the first practical example I/
Instead of the twisted plate (4), a stirrer rod (lO) with an elongated plate (6) spirally wound around the rod (5) as shown in Fig. 4 is used as a heat exchanger tube (2). in the outer cavity of
It is inserted in the tube axis direction of the heat exchanger tube (2), and the rod (5
) are fixed to the tube plate (3). The width of the plate (6), the twist pitch, and the size of the rod (5) are determined by the size of the heat exchanger tube gap, the flow rate of the fluid outside the heat exchanger tube (2), etc.

Next, the present invention will be explained in detail. In the second embodiment, since a swirling flow is generated as in the first embodiment, a large temperature gradient can be obtained near the outer surface of the heat exchanger tube (2).

Next, a third embodiment of the present invention will be described with reference to FIG. In the heat exchanger of this embodiment, instead of the twisted plate in the first embodiment, protrusions (7) consisting of a large number of rectangular parallelepipeds extending radially around a rod (5) are fixed as shown in FIG. A stirring rod (11) is inserted. In the case of this embodiment as well, the flow of the fluid is disturbed and stirred as in the previous embodiment, so that the temperature gradient of the fluid near the outer surface of the heat transfer tube (2) can be increased.

It is clear that various changes can be made to the embodiments described above without departing from the spirit of the invention. For example, in the first embodiment, openings may be provided in the torsion plate (4), protrusions, etc. may be provided, and in the second embodiment, the shape of the protrusions, the number of pitch rows, etc. may be freely selected. be able to. In the shell-and-tube heat exchanger of the present invention, even if the medium flowing inside the heat exchanger flows while evaporating or condensing, the effects of the present invention are not impaired.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line X-X in FIG. 1, and FIG. FIG. 4 is a perspective view showing the main parts of the second embodiment of the present invention, and FIG. 5 is a perspective view of the third embodiment of the present invention.
Fig. 6 is a cross-sectional view showing the structure of a conventional multi-tube heat exchanger, Fig. 7 is a perspective view showing four parts of the embodiment.
It is a sectional view showing a -X cross section. l...Cylindrical body, 2...Heat transfer tube, 4...Twisted plate,
5... Bar, -1,

Claims (4)

[Claims] (1) In a multi-tubular heat exchanger consisting of a plurality of heat exchanger tubes and an outer shell that houses the heat exchanger tubes, a stirring rod that stirs a fluid is placed in the gap between the heat exchanger tubes in the outer shell. A multi-tube heat exchanger characterized by being inserted and arranged along the tube axis direction. (2) The shell-and-tube heat exchanger according to claim 1, wherein the stirring rod is a rod formed of twisted plates. (3) The shell-and-tube heat exchanger according to claim 1, wherein the stirring rod is a rod having a large number of rectangular parallelepiped protrusions extending radially from the shaft. (4) The multi-tubular heat exchanger according to claim 1, wherein the stirring rod is a rod having a flat plate wound spirally around a cylindrical rod.