JPS63251792A - Thermal conducting pipe with deep fins of fine pitch - Google Patents

Abstract

PURPOSE:To enable a thermal conducting area of maximum degree to be supplied with a low cost by a method wherein a thin plate is bent in an alternative inner and outer V-shaped or V-shape with rounded corners, wound in a tubular form to seal aligning edges to make a finned tube, and a small cylindrical end part is formed at both end portions and this is inserted into a plug and brazed or welded thereto. CONSTITUTION:A thin plate is bent in an alternative inner or outer directions to form a V-shaped form. A part of a finned tube 1 wound in a cylindrical form is shown. In this condition, both end portions of the fins are kept open. End portions are sealed and a cylindrical part is formed in respect to segments (a), (b) and (c) of the fins. Each of points (d) and (e) is set on lines ab and cd to make a relation of bd=be, an end part of valley of the V-shape part is picked up with a picking tool to cause between bd and be to be closely contacted to each other in a proper width, a remaining ab and ce is crashed with a proper width to make a smooth part and this part is formed to have a part of the cylinder or a multi-sided cylinder 2. The cylinder part 2 at the end part of the formed finned tube is fitted into the spigot part of the plug 3, welded or brazed. The finned thermal conducting pipe is formed into a multi-layer type, thereby its multiplicity can be further increased.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the improvement of a locked heat transfer tube for a heat exchanger, and it is possible to extremely increase the heat transfer area of one tube by a simple method, and to achieve a low temperature and This article relates to fine pitch deep pleated heat exchanger tubes that are not only applied in the field of heat exchangers that require particularly high performance, such as gas-to-gas heat exchange with poor heat transfer coefficients, but also widely used for general purposes. It is something.

[Conventional technology]

Conventionally, in heat exchanger tubes in the field of heat exchangers.

The currently popular methods of providing as much heat transfer area as possible within a limited space include (1) fin tubes;
There are (2) fluted tubes, (3) knurled tubes, etc.

It is difficult to apply fins to both sides of the finned tube (1), the fluted tube (2) does not have a large area magnification, and the same is true of the knurled tube (3).

Furthermore, as a compact heat exchanger for gas to gas,
There are regenerative types and honeycomb types, but both have limited uses and have low temperature efficiency because the flow does not form an alternating current.

On the other hand, the pleated tube for heat exchanger by the inventor
291,894) achieves complete alternating current and is compact, it is desirable to further improve performance.

[Problem that the invention seeks to solve]

Previously proposed pleated tubes were made by forming pleats from a single tube using a roll or press, or by making a corrugated plate using a bending method, winding it into a cylinder, and seal-welding the seam. Then, one side of a short circular tube with approximately the same diameter was made into a mold by die forging and used as a cap.
These were fitted together and welded or brazed, but both had limitations in forming and processing, and the pitch of the folds could not be made very small relative to the depth, so the area magnification I couldn't make it bigger.

c. Means for Solving Problems] In order to solve the problems of the prior art as described above, the present invention provides a molded heat exchanger tube in which the depth of the folds can be made as deep as possible and the pitch thereof can be made as small as possible. The structure was made by bending a thin plate alternately inside and outside into a V-shape or a V-shape with rounded corners, and rolling it into a tube, and sealing the seams. At both ends of the pleated tube, the part from the bottom of the groove to the vicinity of the top is deformed to an appropriate width, sealed and sealed, and the top thereof is smoothly pressed and bent to form a cylinder that is slightly smaller than the outside diameter of the pleated tube. It is characterized by forming an end portion, inserting it into a cap having an outer diameter slightly larger than or equal to the outer diameter of the pleated tube, and brazing or welding it.

In other words, the heat transfer tube of the present invention has the feature that the deeper the pleats and the finer the pitch, the easier the processing becomes due to the above structure, and it is possible to greatly expand the heat transfer area. extremely suitable for

Moreover, by pre-knurling the inside and outside of these folds or any necessary surface, the heat transfer area is further expanded, and the turbulent flow promotion effect of the unevenness increases the heat transfer coefficient, resulting in an even greater synergistic effect. You can get it.

The most important point of the present invention is to make it possible to easily and reliably process both ends of a pleated tube having deep folds at a fine pitch into a cylindrical shape having a slightly smaller outer diameter. As a result, it becomes possible to supply heat transfer tubes that have the maximum heat transfer area in a limited space at low cost.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a part of a pleated tube 1 which is formed by bending a thin plate into a V-shape by alternately bending it inward and outward, and then winding it into a cylindrical shape. In this state, both ends of the folds are open, and the method for sealing the ends and forming the cylindrical part will be explained by focusing on one of the folds a, b, and c.

In FIG. 1, points a and C correspond to the peaks of the mountain, and points gaa and cc correspond to the watershed lines of the mountain. The dot is the bottom point of the valley, and the straight line bb is the bottom line of the valley, and the distance between each watershed line and the bottom line is equal.

Now, take points d and e on lines ab and cb, respectively, and find b
Set d=be, pinch the end of this V-shaped valley with the beak to make a proper width between bd and be, and then press the remaining ad.
, ce are pressed to a suitable width to make it smooth, and then molded so that it becomes a part of a cylinder or polygonal cylinder 2.

By sequentially performing this operation on adjacent valleys, the end of the tube is formed into the shape shown in FIG. 2.

In Fig. 2, bd and be are in close contact with each other with an appropriate width to form a plate shape, and between da and ec is a cylinder 2 with an appropriate width.
It has become part of. As a natural result, the outer diameter of the cylinder is
The outer diameter is slightly smaller than the outer diameter of the pleated tube 1, but the degree to which it becomes smaller depends on the shape of the area near the top of the mountain, points a and c. The outer diameter of the polygonal cylinder 2 does not have to become too small.

This relationship is shown in FIGS. 3 and 4.

FIG. 3 shows a part of a cross-section of the pleated tube 1 before the end is deformed as shown in FIG. As shown in the figure, there is a relatively large roundness near the peaks a and C of the mountain, and the distance m a d is created by this roundness.

ce is taken larger, and as a result, the distance bd,
Since it is not necessary to make be too small, the outer diameter of the cylindrical or polygonal cylindrical portion 2 can be adjusted as shown in FIG.
It is not much smaller than the outer diameter of.

The close contact ends bd and be may be deformed and welded at the same time using a resistance welder, or may be sealed by soldering or brazing after the close contact processing.

FIG. 5 shows how the cylindrical portion 2 at the end of the charging tube formed in this manner is fitted into the seal portion of the cap 3 and welded or brazed.

FIG. 6 is a modification of FIG. 4 in which the ends of the pleats are cut diagonally to reduce resistance to fluid entry and exit. Note that usually a small roundness is made at the bottom of the fold, so if you crush it and make it stick, the tip of the valley will come out at point b', which is inside the original point b, as shown in 4 in Figure 4. It is better to cut this part out in advance.

The inward protruding portions, such as b' in FIG. 4, may be cut later, or may be locally pushed out or bent in an appropriate manner.

In addition, in order to make the folds deeper than those in Figure 3,
As shown in Figure 7, if you add shallow folds p every other time, the center part will not be crowded.

A thick molded pipe with such a simple structure can serve as both a chimney and an air preheater, and can also be used for energy saving.

In the case of an extremely large size, it is also possible to create a configuration as shown in FIG. 8, in which waves W with a finer pitch are added to the solid part of the folds shown in FIG. 7.

However, in this case, this wave W is not added to the end. In addition, in FIG. 7, 5 is a core disposed at the center of the molded tube 1, 6 is a spacer, and 7 is an outer cylinder.

Therefore, to explain the heat transfer area of the heat transfer tube of the present invention,
It is as follows.

With the dimensions shown in FIG. 4, the inner and outer areas of the folds are about four times the surface area of a cylinder with the same outer diameter. By knurling both the inner and outer surfaces, this heat transfer area becomes approximately 1.5 times that amount, and due to the turbulent flow effect due to the uneven surface, the heat transfer coefficient increases from approximately 1.5 times to 2 times depending on the flow velocity. Their synergistic effect is 4Xl, 5X (1,5-2) = 9-12 times.

That is, the knurled formed tube having the shape shown in Fig. 4 is 1
It has the heat transfer characteristics of 9 to 12 books.

Furthermore, once complete alternating current is achieved, the temperature efficiency is 100
%, so if it is used under conditions where a conventional type would have a temperature efficiency of 75%, the efficiency would be 1.33 times, so the above magnification would reach 12 to 16 times. It happens.

In addition, by configuring this molded heat exchanger tube in a multilayer type, the magnification can be further increased and it is also cheaper, so it is possible to provide a higher performance and cheaper heat exchanger.

Note that by appropriately combining such units in series or parallel, it is possible to easily apply the device to extremely large-capacity applications.

Furthermore, since the molded heat exchanger tube is assembled with a joint that has a sealing part with a packing or O-ring,
It has the great advantage of being easy to disassemble, clean and assemble, and because each row of parallel units can be disconnected during operation by operating a valve and disassembled and inspected and cleaned, it can be used even in areas that get dirty easily.

〔Effect of the invention〕

Since the present invention is as described above, it is particularly suitable as a heat transfer tube for heat exchangers that require high performance, such as compact gas-to-gas heat exchangers, and can be used as a heat exchanger tube for other heat exchangers as necessary. It is also commonly used for heat exchanger tubes.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a part of a heating tube formed by processing a thin plate, FIG. 2 is a perspective view of an example of the heat exchanger tube of the present invention formed by processing the heating tube of FIG. 1, and FIG. Fig. 4 is a front view of the heating tube shown in Fig. 1, Fig. 4 is a front view of the heat exchanger tube shown in Fig. 2, and Fig. 5 is a sectional view showing the state in which the cap is attached to the cylindrical end of the heat transfer tube shown in Fig. 4. , 6th I2! 5 is a cross-sectional view showing a modification of FIG. 5, FIG. 7 is a front view of another example of the heat exchanger tube of the present invention, and FIG. 8 is a front view of a part of the same example.

Claims (1)

[Scope of Claims] 1. A pleated tube is constructed by bending a thin plate alternately inside and out into a V-shape or a V-shape with rounded corners and winding it into a tube, and sealing the seams. The area from the bottom of the valley to the vicinity of the top is deformed to an appropriate width, sealed and sealed, and the top beyond that is pressed and bent smoothly to form a cylindrical end slightly smaller than the outer diameter of the pleated tube, and then A fine pitch deep pleated heat exchanger tube characterized by being inserted into a mouthpiece having an outer diameter slightly larger than or equal to the outer diameter of the pleated tube and then brazed or welded. 2. The fine pitch deep pleat type heat transfer tube according to claim 1, wherein both the inner and outer heat transfer surfaces are knurled. 3. The fine pitch deep pleat type heat exchanger tube according to claim 1, wherein either the inner or outer surface of the heat transfer surface is knurled.