JPH03251686A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve heat exchanging efficiency by a method wherein a heat exchanger is provided with fin tubes made of aluminum, outer tubes made of titanium and couplings connected to both ends of the outer tube while recesses and projections are formed on the surface of fin sheets, compressed radially and pushed against an inner tube. CONSTITUTION:In a heat exchanger 15, an aluminum fin tube 17 is arranged at the outside of a titanium inner tube 16 while a titanium outer tube 18 is arranged at the outside of the fin tube 17. The fin tubes 17 are arranged radially and are provided with a multitude of fin sheets 19, on which recesses and projections are formed on the surface thereof, and a supporting tube 20, further, the fin sheets 19 are attached to the inner tube 16 under pushed condition. The fin sheets 19 are formed with recesses and projections and is brought into contact with the inner tube under pushed condition in such a manner whereby heat exchanging efficiency can be improved. On the other hand, the fin tube 17 is made of aluminum and, therefore, press forming is easy and the length of the fin sheets can be secured sufficiently. The outer tube made of titanium is arranged so as to be brought into close contact and, therefore, the fin tube made of aluminum can be protected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger that has low pressure loss in fluid passing through the heat exchanger and is highly efficient, and is used mainly for cooling liquids and the like.

[Conventional technology]

FIG. 6 shows a cross section of the main part of the heat exchanger 10 used for cooling seawater. As shown in the figure, an outer tube 11 has fin plates 12 radially formed inward on the outside of the inner tube 11. 13
The structure was such that a corrosive liquid such as seawater or plating liquid was passed through the inner tube 11, and a refrigerant was passed between the outer tube 13 and the inner tube 11 to cool the seawater.

[Problems to be Solved by the Invention] Outer tube 1 in which fin plates 12 are formed radially inward.
3 was manufactured by hot isostatic extrusion or hot forging, so even if small diameter pipes could be manufactured,
In the case of large-diameter pipes, it is difficult to manufacture them with sufficient height for the fin plates that project radially inward.

Of course, even large-diameter pipes can be manufactured as long as the height of the fin plate is low, but in this case, the cross-sectional area through which the refrigerant passes is reduced, resulting in an increased pressure loss.

Therefore, as a result of intensive research, the inventor of the present invention found that it is possible to form a fin plate with a high height by manufacturing the fin tube with the fin plate inward from aluminum (including aluminum alloy). I understand.

However, if the fin tube is made of aluminum, it is strong against refrigerants such as Freon gas, but if it is exposed to seawater or other corrosive liquids from the outside, the outside will be easily corroded by the salt, acid, alkali, etc. it contains. Additionally, there was a problem in that it was difficult to weld aluminum and dissimilar metals at the end portions.

The present invention has been made in view of these circumstances, and provides a heat exchanger and method for manufacturing the same that has low pressure loss, can be manufactured at low cost even in large diameters, and has further improved efficiency than conventional heat exchangers. The purpose is to provide

[Means to solve the problem]

The heat exchanger according to claim (1) which meets the above object includes a titanium inner tube having an inlet and an outlet, and a number of fin plates whose tips abut against the outside of the titanium inner tube. an aluminum fin tube whose cross section protrudes radially inward; a titanium outer tube disposed in close contact with the outside of the fin tube;
The fin plate has a joint connected to each end of the outer tube, and the fin plate has an uneven surface and is compressed in the radial direction and pressed against the inner tube.

Further, the heat exchanger according to claim (2) includes a copper inner tube having an inlet portion and an outlet portion, and a number of fin plates whose tips abut on the outside of the inner tube, the cross section being radially inward. It has a protruding aluminum fin tube, a copper outer tube disposed in close contact with the outside of the fin tube, and joints connected to both ends of the outer tube, and the fin plate has a surface. Concave and convex portions are formed and are compressed in the radial direction and pressed against the inner tube.

Here, aluminum includes pure aluminum and aluminum alloys, and copper includes copper and copper alloys.

[Effect]

In the heat exchanger according to claims (1) and (2), since aluminum is used for the fin tube, it is easy to fabricate a fin tube with a fin plate having a high height in the radial direction and having an uneven surface. The fin plate is compressed in the radial direction and is in contact with the inner tube, thereby improving the heat transfer efficiency. Furthermore, since an outer tube made of a metal tube with good corrosion resistance and weldability is placed closely on the outside of the fin tube, this protects the aluminum fin tube.
Ensure corrosion resistance.

【Example〕

Next, embodiments embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.

XXII, FIG. 1 is a sectional view of the main parts of a heat exchanger according to an embodiment of the present invention, FIG. 2 is a plan view of the heat exchanger, and FIG. 3 is a side view of the heat exchanger. FIG. 4 is a partial sectional view of a heat exchanger according to another embodiment, and FIG. 5 is a flow chart showing the manufacturing process of the heat exchanger.

As shown in FIG. 1, a heat exchanger 1 according to an embodiment of the present invention
5, an aluminum fin tube 17 is placed outside an inner tube 16 made of titanium, and an outer tube 18 made of titanium is placed outside of the fin tube 17 made of aluminum.

The fin tubes 17 are arranged radially and have a large number of fin plates 19 each having an uneven surface, and a support tube 20 that supports the fin plates 19 from the outside. 16 in a pressed state.

A method for manufacturing the heat exchanger 15 will be described with reference to FIG. 5. An outer tube 18 and an inner tube 16 having predetermined diameters and an aluminum fin tube 17 are manufactured in advance by a drawing method. here,
The side surface of the fin plate 21 inside the fin tube 17 has a first
As shown in the figure, it is assumed that linear unevenness 21 is formed in the drawing direction.

First, a titanium outer tube 18 is placed on the outside of the fin tube 17.
Attach. In this case, the inner diameter of the outer tube 18 is made larger than the outer diameter of the fin tube 17 by about 1 to 2.

Next, these are passed through a die to reduce the diameter by about 5 liters, for example, if the outer diameter of the outer tube is 60s+-. This brings the outer tube 1B into close contact with the fin tube 17.

Then, the inner tube 16 is inserted inside the fin tube 17. In this case, the inner tube 16 is inserted so that a gap of about 1 to 2 mm is provided between the outer diameter of the inner tube 16 and the inner diameter of the fin plate 21. Select dimensions.

Thereafter, with the inner tube 16 inserted, it is again passed through a die and subjected to cold drawing to reduce the diameter of the entire tube by about 5-1. This brings the fin plate 21 into contact with the inner tube 16 in a compressed state, improving the contact between the fin plate 21 and the inner tube 16.
Thermal conductivity will be improved.

Next, the end structure of the heat exchanger 15 will be explained with reference to FIGS. 2 and 3. A titanium T-joint 22 having a diameter that can be attached to the end of the outer tube 18 is prepared. One end 23
is attached to the outer tube 18 by welding, and a titanium reducer 25 is connected to the other end 24 by welding. Furthermore, this reducer
The small diameter part 26 of 25 is made into a part into which the inner tube 16 can just fit, and is welded to the inner tube 16 at the small diameter part 26 to achieve a complete airtight seal.

As shown in FIG. 4, one end of the T-joint 22 is welded to the outer tube 18, an end plate 27 made of titanium is arranged at the other end, and the outside of the end plate 27 and the T-joint 22 are welded. , and further the end plate 2
The entire seal can also be achieved by welding the inside of 7 and the inner tube 16.

When using the heat exchanger 15, seawater (or corrosive liquid such as plating liquid, etc.) is passed inside the inner tube 16, and a refrigerant (for example, Freon gas) is injected into the outer fin tube 17 from the T-joint 22. In this case, the fin plate 19 has unevenness 2.
1 is formed and the surface area is increased, heat transfer efficiency is improved, and since the fin plate 19 and the provided unevenness 21 are formed parallel to the direction of movement of the refrigerant,
Fluid resistance can be reduced.

In the above manufacturing method, the finned tube was first placed in the outer tube to reduce its diameter, and then the inner tube was placed in the reduced diameter finned tube to further reduce its diameter. The diameter is reduced,
Next, it is also possible to manufacture a heat exchanger by inserting a fin tube with a reduced diameter into the outer tube and further reducing the diameter.

In the above embodiments, titanium was used for the inner tube, the outer tube, and the joints attached thereto (including the end plates), but depending on the purpose of use, the inner tube, the outer tube, and the joints attached thereto,
The end plate can also be made of copper or a copper alloy, and the manufacturing method is also different from that of using titanium.

〔Effect of the invention〕

As is clear from the above description, in the heat exchanger according to claims (1) and (2), unevenness is formed on the fin plate disposed on the outside of the inner tube, and moreover, the heat exchanger has unevenness formed on the fin plate disposed on the outside of the inner tube. Since they are in contact with each other, heat exchange efficiency is improved.

In addition, since the fin tube in which the fin plate is provided is made of aluminum, extrusion molding is easy, and even in a large-diameter heat exchanger, a sufficient length of the fin plate can be ensured. It can be manufactured by providing irregularities on its surface.

Since the outer tube made of titanium or copper is closely placed on the outside of the finned tube made of aluminum, it is possible to protect the inner finned tube made of aluminum, and it is easy to attach a joint to the end. Can be joined by welding.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of a heat exchanger according to an embodiment of the present invention, FIG. 2 is a plan view of the heat exchanger, FIG. 3 is a side view of the heat exchanger, and FIG. FIG. 5 is a flowchart showing the manufacturing process of the heat exchanger, and FIG. 6 is a sectional view of the main parts of a conventional heat exchanger. [Explanation of symbols] 15--Heat exchanger, 16--Inner tube, 17-
--1--fin tube, 1B---outer tube, 19--
---Fin plate, 20------1...Support tube, 21
−・−・−Unevenness, 22, −・−・T joint, 23−・−
--------One end, 24-...---One end, 25
−−−−−−−1・Reducer−126−・・−−−
One small diameter part, 27-・-・-・end plate

Claims (2)

[Claims] (1) Aluminum fins with a titanium inner tube having an inlet and an outlet, and a number of fin plates whose tips abut against the outside of the titanium inner tube, projecting inward in a radial cross-section. It has a tube, an outer tube made of titanium that is placed in close contact with the outside of the fin tube, and joints connected to both ends of the outer tube, and the fin plate has irregularities formed on its surface, A heat exchanger characterized in that the heat exchanger is radially compressed and pressed against the inner tube. (2) A copper inner tube having an inlet and an outlet, an aluminum fin tube with a number of fin plates whose tips abut against the outside of the inner tube and protrude inward in a radial cross-section; It has an outer tube made of copper that is placed in close contact with the outside of the fin tube, and a joint connected to both ends of the outer tube, and the fin plate has an uneven surface and is compressed in the radial direction. A heat exchanger characterized in that the heat exchanger is pressed against the inner tube.