JPS62194193A - Annular piping type heat exchanger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a piping type heat exchanger with a series of heat exchange fins, that is, a first heat medium is placed inside the pipe type heat exchanger. A plate-shaped fin is used to flow the second heat medium around the outer periphery and increase the heat transfer area. +31 J'l is applied to the heat exchanger penetrated inside.

In particular, the present invention relates to a heat exchanger in which the heat exchange fins are firmly attached to the annular heat exchange pipe by radially expanding the heat exchange pipe and firmly engaging the heat exchange fins.

(Prior Art) The present invention is applicable to the above-mentioned piping-type heat exchanger, in which the medium flowing inside the piping is a liquid or a medium whose phase visually changes during the heat exchange process, and the medium flowing outside the piping is a gas. Regarding the exchanger.

This heat exchanger is used in industrial applications and in corrosive atmospheres. First, the heat exchanger is for extracting heat from the flue gas, such as when oil or coal is burned at power. Heat exchangers need to be strong and robust to achieve this purpose. These heat exchangers are therefore made of steel. If the heat exchanger is used in a corrosive atmosphere, it is necessary to coat the surface of the heat exchanger with an impermeable anticorrosion agent, such as enamel, unless the entire heat exchanger is non-corrosive. Therefore, the present invention comprises a series of heat exchange fins which are firmly attached by expansion of the pipe and which are made of steel and have an impermeable surface of a scratch-resistant material, preferably enamel. The purpose is to provide a piped heat exchanger with a coating.

Generally speaking, in the case of pipe heat exchangers in which liquid flows inside the pipes and gas flows outside, it is recognized that the heat transfer coefficient of gas is considerably smaller than that of liquid.

Therefore, it is necessary to increase the surface area on the outside of the pipe. The two most commonly used means to accomplish this are:

a) A twisted flange is provided on the outside of the heat exchange piping. This flange is normally welded to the pipe in order to eliminate heat transfer resistance at the joint between the flange and the pipe. In addition to rotary storage heat exchangers that directly exchange heat between two gases, such as L-Jungström type storage air heaters, industrial applications are also available where a larger external heat transfer surface is required. The most commonly used type is one that is attached to a pipe wound in a U-shape, that is, a spiral fin is attached along the pipe.

Otherwise, a tubular heat exchanger with smooth piping is used. Since rotary heat exchangers are prone to gas leakage, these rotary heat exchangers have gradually been replaced by spiral pipe type heat exchangers.

b) A series of fins were installed on the outside surface of the heat exchange piping to increase the surface area.

This fin is made in a standard design for multiple heat exchange piping. These series of fins are commonly used in general ventilation (heating and cooling) or similar purpose equipment. Therefore, the piping and fins of such heat exchangers are relatively small in diameter, and they are made of soft materials such as copper or aluminum. Previously, means have been proposed to achieve good heat transfer between the piping and the fins. That is, good contact at high contact pressures at the joints between them is due to the radial expansion of the piping and the tight engagement of the fins on the piping.
``It's about getting kicked.''

This is achieved hydraulically by means of a circular body drawn around the mandrel, ie the circumference of each pipe, or by means of a fluid pumped to high pressure passing through the pipe. Both of these measures are based on expanding the pipe radially beyond the elastic limit of its material, thus making it possible to obtain permanent deformations and high contact pressures.

With respect to series of fins used in heat exchangers for general ventilation and similar purposes, the fins cannot be rigidly attached by mechanically or hydraulically expanding the piping by the means described above. It's relatively easy. In such devices, the tubing and fins used are of small diameter and made of soft materials, such as steel or aluminum. In addition, the fins are attached to a resilient collar located in the aperture through which the heat exchange piping passes completely.

This helps with the expansion action and allows a constant and uniform distribution of the contact pressure between the pipe and the fins. This collar also often acts as a subena between the fins.

(Problem to be Solved by the Invention) However, the application of this type of series of fins to the above-mentioned industrial fields has not yet been carried out, despite the advantages obtained with heat exchangers with spiral piping. Not yet.

These advantages are:

The ability to greatly expand the surface area.

Low pressure loss.

A more stable heat exchange structure.

It must be an inexpensive heat exchanger.

Thus, the more robust tubular heat exchangers required for industrial applications primarily include helical, curved piping, and in some cases smooth piping. These piped heat exchangers are mostly made of steel. There are several reasons why a series of fins with the configuration described above is not used in the industrial field. For example, a number of difficulties and problems arise when these series of fins are made of steel, especially when provided with a protective surface coating.

The main of these issues are:

a) Expanding steel heat exchange piping in the radial direction
It's quite difficult. In order to hydraulically expand ma pipes, a working pressure of about 1000 bar is required for pipe thicknesses normally required for such heat exchangers.

b) It is difficult, although not impossible, to remove the J-fin from the elastic collar provided around the opening through which the pipe passes. In particular, cracks may appear in the collar.

C) When applying a protective coating, for example an enamel coating, to the surface of a heat exchanger, it is difficult to ensure sufficient impermeability of the coating, which is required to provide sufficient protection against corrosion.

In order to provide sufficient impermeability to the enamel surface, the surface of the heat exchanger to which the enamel coating is applied must be completely smooth and free of all cracks, other dents, etc. These surfaces must be free of readily removable surface materials, such as welding slag or welding beads. These surface materials can be knocked off or otherwise removed when cleaning the heat exchanger or for similar reasons. Removal of such surface material tends to create indentations in the enamel surface.

It is impractical to use means of attaching a resilient collar around the apertures in the fins through which the piping passes. This is because cracks and notches around the collar damage the enamel coating. In particular, such cracks and notches form air bubbles in the enamel layer, which eventually rupture. They also result in incomplete surface coverage and susceptibility to corrosion losses. In addition, with such a configuration, it is impossible to securely hold the fins and increase the number of GJ. It is clear that deflection of the resilient collar avoids cracks in the enamel coating.

(Structure of the invention) (Means for solving the problems) These problems are solved by a series of fin structures specified in the claims of the present invention. Solution according to claim 1 According to the means, the heat exchange fins have a substantially flat plate shape and are disposed on six planes that intersect with the axis of each pipe in the region that contacts each heat exchange pipe. This means that there are no collar-like bends or other bends in the fins that cover the surface that contacts the heat exchange piping.

This solution avoids forming gaps between the fin collar and the pipe. This gap provides a hidden recess for oil and steam air to enter, and when surface treating fin piping equipment, e.g. by enameling or burning the surface coating in an approximately 800"C'C" furnace. This solution also allows the fin to be securely attached to the pipe without a resilient mounting member. The expansion range in the radial direction of the piping required to attach it to [) is C smaller than that of the conventional 6.

According to the solution according to claim 2, it is possible to engage the piping in openings in the fins formed by sophisticated drilling means. Further, the fin surface that comes into contact with the heat exchange piping can be made parallel to the axis of each piping over approximately the same length as the entire length of the opening. This solution ensures heat transfer contact between the fins and the pipework over the entire surface of the aperture wall. When the apertures that engage the piping are drilled into the fins by conventional drilling means, the walls of the apertures assume a slightly conical shape.

This creates gaps on the sides of the pipe walls, which prevents adequate heat transfer contact. However, these and other problematic consequences can be avoided by taking the solutions described above.

This solution also reduces the expansion range of the pipe required to securely attach the fin to the pipe.

Claims 3 and 4 describe the most appropriate shapes of piping and fins when the present invention is applied to a series of fins made of lA.

According to the solution described in claim 5, the fins are firmly attached to the heat exchanger by expanding the outer circumferential surface of the piping outward. One of the special advantages made possible by hydraulic expansion of pipes is that
This means that the piping expands outward within the fin space only slightly. This contributes to achieving a firmness of the fins and also makes it possible to check the degree of expansion by measuring the piping between the fins.

The solution specified in the above-mentioned patent claims completely moisturizes the surfaces of the fins and pipes in heat exchangers, such surfaces being suitable for the purpose of surface treatments, including industrial coatings. Particularly suitable.

This heat exchanger has a large special heat transfer surface that reduces the pressure drop of the gas flowing through it. Anything that tends to impair heat transfer can be immediately removed from the coating. This is because the clean hM means reaches all the members of the heat exchanger and there is no interference from foreign objects. Also, the heat exchanger can be produced quickly and at a much lower cost.

Claims 6 and 7 specify preferred embodiments of the heat exchanger with respect to end plates.

This is often necessary to securely attach the heat exchanger to the equipment assembly.

Claim 8 specifies the surface treatment of the heat exchanger described above. This is often necessary when heat exchangers are used in corrosive atmospheres.

(Example) In FIG. 1, a heat exchanger 10 consisting of end plates 12, heat transfer fins 14a3, and heat exchange piping 16 is shown. The piping passes through apertures 18 in the fins and end plates. The positions of the openings and piping in this embodiment are as shown in FIGS. 2 and 3. In the heat exchanger according to this embodiment, two heat exchange pipes are disposed on the connecting member 20 outside the end plate 12.

On the other hand, other pipes are connected to the bent pipe 22. This curved pipe 2
2 is bent by 180 degrees and connected to two pipes to form a curved passage. The bent tube and the connecting member are connected to the heat exchange pipe by a welded joint 23.

The end plate 12 is mounted on a right angled flange 24 extending C along the longitudinal side of the end plate. This flange 24 increases the stability provided to the end plate 12 and the heat exchanger.

If appropriate, a similar flange may be provided on the short side of the end plate. This flange is for mounting the heat exchanger as a rigid assembly.

However, it is useful for connecting the heat exchanger to other conduit systems or for assembling a large heat exchange member by sequentially connecting a large number of heat exchanger members one by one.

FIG. 4 is a detailed cutaway view of the piping and fin arrangement, illustrating the arrangement in which the fins 14 are securely attached to the heat exchange piping 16 by hydraulic expansion of the piping. Fourth
As shown in the figure, pipe J3 and fins are covered with protective enamel layer 2.
Coated with 6. Also, according to the figure, the pipe wall between the fins adjacent to phase H and J has expanded slightly as shown at 28. These bulges are formed when the piping is hydraulically strained.

The bulge formed in this way serves to securely hold the fin. By measuring the pipe diameter between the fins in one direction, it is possible to check the expansion caused. FIG. 5 shows a similar detailed view of a known series of fins used in connection with general ventilation equipment. In this conventional construction, the fins 30 are provided with resilient canisters 30 around the apertures through which the heat exchange piping 34 passes.
It is attached to 2. Since the fins in this construction are thin and made of a soft material, such as aluminum, it is possible to form the collar in a simple shape from the material of the fin itself. In this case, the collar also functions as a cross between each fin. However, the main purpose of the collar is to ensure sufficient contact surface between the heat exchange piping and the fins to provide sufficient contact pressure, thereby obtaining sufficient heat transfer conditions. . The fins are firmly attached in position by expanding the heat exchange tubing. The expansion necessary to provide sufficient contact pressure is due to the fact that the heat exchange piping has a small wall thickness and is made of a soft material such as copper, and that the collar is at the connection between the fins and the heat exchange piping. It is promoted by having a certain degree of resilience).

Comparing the structure according to the invention shown in FIG. 4 with the conventional structure shown in FIG. Compatibility is not possible. The structure of fissures, cracks, and dents around the collar 32 shown in FIG. 5 is an obstacle to obtaining a sufficient enamel surface. Similarly, the elasticity of the joints between the fins and the respective pipes can also lead to the formation of cracks in the enamel layer.

As shown in FIG. 4, no cracks are observed between the fin collar and the heat exchange piping in the heat exchanger structure according to the present invention. The surfaces of the fins and piping of the heat exchanger shown in Figure 4 are almost completely smooth, and if the surface is coated with enamel, for example, this coating will be quite durable and completely impermeable. Layers and vines. Furthermore, since the fins are rigidly mounted, no elasticity that would damage the enamel layer is visible at the points where the fins join the respective pipes. The advantage of this rigid mounting is also that the range of radial hydraulic and other expansion of the heat exchange piping required to rigidly mount the fins is greater than that of conventional heat exchanger piping. is often smaller than the required expansion range, so that a series of fins can be firmly attached to each pipe.

6 and 7 show a heat exchanger according to the present invention which has been improved in, among other things, the above points. This means that the apertures 18 in the fins that bring the heat exchange piping into heat transfer contact with the fins
This is achieved by elaborately shaping the fins so that the contact surfaces J' to the heat exchange pipes in the apertures are parallel to the longitudinal axis of the pipes, and in fact parallel over the entire length of the apertures. According to conventional drilling techniques, as shown in FIG. 6, the apertures drilled into the fins will have slightly conical walls 36. Such a conical surface clearly creates a gap 38 with the heat exchange pipe 16, which could damage, for example, an enamel-coated surface. The seventh hole can be made by more elaborate drilling techniques or other sophisticated techniques.
It is possible to provide an aperture with a hole wall 40 as shown. This hole wall is parallel to the longitudinal axis of the pipe,
It is also parallel to the original cylindrical surface of the pipe, practically along the entire length of the aperture. However, it undergoes a slight slope 42 adjacent where the puncher passes the fin. If the apertures are formed more precisely as shown in FIG. 7, the gap will be less likely to damage the coated surface formed between the pipe wall and the fin aperture, for example, the enamel coated surface. It also provides a highly durable and strong enamel surface. Significant heat transfer between the fins and the piping is ensured by the contact surfaces between them having a high, homogenized contact pressure, which is then increased by the hydraulic expansion of the piping. In general, the range of expansion of the heat exchange piping required to firmly hold the fins is smaller than in the prior art.

The invention is not limited to the heat exchanger embodiments described above, but may be modified within the scope of the claims.

[Brief explanation of drawings]

An embodiment of the heat exchanger according to the present invention will be explained with reference to the following drawings. Fig. 2 is a side view of the heat exchanger. Fig. 3 is a diagram showing a single fin plate provided in the heat exchanger. Fig. 4 shows a single fin plate according to the present invention.
FIG. 4 is a diagram showing a partial cross-section of the heat exchange piping shown in FIG. FIG. 5 is a partial cutaway view of heat exchange piping in a series of fins according to the prior art. FIG. 6 is a diagram showing a part of the heat exchange piping that contacts the fin plate according to the present invention, and shows that the holes in the fin plate are formed by the conventional drilling technique. FIG. 7 shows a part of the heat exchange piping in contact with the fin plate according to the present invention, and the holes in the fin plate are formed by a sophisticated drilling technique.

Claims (1)

[Claims] 1. An annular pipe (16) for guiding a first heat medium, and a fin (14) for enlarging the surface area attached to the outer surface of each annular pipe and in contact with the second heat medium. Consisting of
The piping is provided through apertures (18) formed in each fin.
In an annular pipe heat exchanger, the fins (14) are rigidly attached to the outer periphery of the respective pipe by expanding the pipe and engaging the outer periphery of the pipe with the fins. Fins that contact the pipe (1
The region 4) has a substantially flat plate, is disposed on a plane orthogonal to the longitudinal axis of the annular pipe (16), and is composed of a single plate thickness, that is, the area near the contact surface with the annular pipe (16). An annular piping type heat exchanger characterized in that the fin plate has no collar-shaped bent portions or other shaped bent portions. 2. The aperture (18) formed in the fin and engaging and fixing the annular pipe (16) is such that the contact surface of the aperture with respect to the annular pipe (16) is aligned with the longitudinal axis of the pipe and at least the axis of the aperture. 2. An annular pipe heat exchanger according to claim 1, characterized in that the annular pipe heat exchanger is formed by elaborate drilling means or other similar means that are parallel to each other along substantially the entire length in the direction. 3. The annular pipe (16) is made of steel and its wall thickness is 0.
An annular pipe heat exchanger according to claim 1 or 2, characterized in that the diameter is 5 to 3 mm, preferably 1 to 2 mm. 4. The fin (14) is made of steel and its wall thickness is 0.4
4. An annular pipe heat exchanger according to any one of claims 1 to 3, characterized in that the diameter is 4 mm, preferably 0.5 to 2 mm. 5. Claim 1, characterized in that the fin (14) is firmly attached to the annular pipe (46) by hydraulically expanding the pipe to expand the outer peripheral surface of the pipe (16). 5. The annular pipe heat exchanger according to any one of items 4 to 5. 6. The annular pipe outside the outermost fin (14) (
16) supporting an end plate (12) rigidly attached to the pipe, and at the same time fins (14) being attached to the pipe in the same manner as said fins are attached. The annular pipe heat exchanger according to any one of items 1 to 5. 7. An annular pipe heat exchanger according to claim 6, characterized in that the end plate (12) is provided with an outwardly directed flange (24). 8, annular pipe (16), fin (14) and end plate (1
8. An annular tubular heat exchanger according to any one of claims 1 to 7, characterized in that both of 2) are covered with a visible protective surface layer (26), for example enamel. .