JPH03238128A - Heat exchanger and its manufacture - Google Patents

Abstract

PURPOSE:To reduce the pressure drop and to improve the efficiency of heat exchanging by forming the projecting and recessing parts on the surface of the fin plate, compressing it to the radius direction and bringing it in pressurized contact with the inner pipe. CONSTITUTION:The outer pipe 18, the inner pipe 16 with the prescribed diameter and the fin pipe 17 of A1 made by the drawing method are manufactured. The projecting and recessing parts of a line like shape in the drawing direction are formed on the side faces of the fin plate 21 inside the fin pipe 17. The outer pipe 18 of copper is mounted outside the fin pipe 17, they are reduced in diameter by passing through the dies and the outer pipe 18 is brought in close contact with the fin pipe 17. When the inner pipe 16 is inserted inside the fin pipe 17, the dimension is so selected as to provide a clearance between the outer diameter of the inner pipe 16 and the inner diameter of the fin plate 21. After then, the cold drawing is executed again through the dies in the state of the inner pipe 16 being inserted, and the diameter reducing is executed. Therefore, the fin plate 21 is brought in contact with the inner pipe 16 in the state of being pressed, the contact of the fin plate 21 with the inner pipe is made well and so the heat conductivity is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a heat exchanger that has a low pressure loss of fluid passing through the interior and is highly efficient, and is used mainly for cooling liquids, etc., and its manufacture. Regarding the method.

[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, fin plates 12 are formed radially inward on the outside of the inner tube 11 made of titanium. The structure was such that an outer tube 13 made of copper was disposed, seawater 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.

[Problem 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, when the fin tube is made of aluminum, it is resistant to refrigerants such as Freon gas, but if it is exposed to seawater from the outside, the outside is likely to corrode due to the salt contained therein. There was a problem in that it was difficult to weld with.

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

[Means for Solving the Problems] The heat exchanger according to claim 1, which meets the above object, includes an inner tube made of titanium having an inlet portion and an outlet portion, and a titanium inner tube provided on the outside of the inner tube made of titanium. An aluminum fin tube with a number of fin plates whose tips abut and which protrude inward in a radial cross-section;
It has an outer tube made of a metal with good corrosion resistance and weldability, which is disposed in close contact with the outside of the fin tube, and has an inlet and an outlet for a refrigerant or heating medium at both ends thereof, and is made of a metal with good corrosion resistance and weldability. The 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 is the heat exchanger according to claim 1, wherein the outer tube is a steel tube,
A copper joint is connected to both ends of the outer tube, and a titanium-copper cladding is used in the middle to seal the joint and the inner tube made of titanium, and the whole is closely welded together. .

The method for manufacturing a heat exchanger according to claim 3 includes an inner tube made of titanium having a predetermined diameter, a finned tube made of aluminum straw having radially formed fin plates inside, and a finned tube made of copper or copper alloy. First, a finned tube is inserted into the outer tube and passed through a die to reduce its diameter.Then, the inner tube is inserted into the reduced diameter finned tube with a gap left inside. Then, the whole is passed through a die to further reduce the diameter, and then predetermined joints are joined to both ends.

Furthermore, the method for manufacturing a heat exchanger according to claim 4 includes:
A titanium inner tube with a predetermined diameter, an aluminum fin tube with radially formed fin plates inside, and a copper or copper alloy outer tube are manufactured in advance, and the inner tube is first inserted into the fin tube and placed in a die. The diameter is reduced through the fin plate and the fin plate is pressed against the inner tube.Then, this reduced diameter fin tube is inserted into the outer tube, and the outer tube is pressed against the fin tube through a die. It is configured to join the joints.

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

[Effect]

In the heat exchanger according to claim 1, since aluminum is used for the fin tube, it is possible to easily manufacture a fin tube having a fin plate having a high height in the radial direction and having an uneven surface. , thereby reducing pressure loss and improving heat exchange efficiency.

Since the fin plate is compressed in the radial direction and is in contact with the inner tube, heat transfer efficiency can be improved, and the outer side of the fin tube is made of a metal tube with good corrosion resistance and weldability. Since the outer tubes are placed in close contact with each other, this protects the aluminum fin tube and ensures corrosion resistance.

Next, in the heat exchanger according to claim 2, the outer tube is made of a steel tube, a copper joint is connected to the end, and the joint and the inner tube are joined using a titanium-copper cladding. Therefore, by welding the outer tube and the fitting, welding the fitting and the copper part of the titanium-copper cladding, and welding the titanium part of the titanium-copper cladding to the inner tube, a seal between the outer tube and the inner tube can be created. Completely done.

In the method for manufacturing a heat exchanger according to claim 3, an inner tube, a finned tube, and an outer tube are manufactured in advance, and the finned tube is first inserted into the outer tube to reduce the diameter of the whole. Since the inner tube is placed inside the diameter-reduced fin tube to further reduce the diameter, the fin plate can be brought into contact with the inner tube in a pressed state, thereby improving heat exchange efficiency. Further, since aluminum is used for the fin tube, a fin tube with a long fin plate can be easily manufactured by extrusion molding, and a large heat exchanger can be easily manufactured.

In the method for manufacturing a heat exchanger according to claim 4, the fin plate is manufactured in a state where it is pressed against the inner tube, and the outer side of the fin plate is further pressed by the outer tube, so that the heat exchange efficiency is improved. Since aluminum can be easily formed, it is possible to manufacture large heat exchangers.

[Examples] Next, examples embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.

Here, 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. 4 is a partial sectional view of the heat exchanger, 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 disposed outside an inner tube 16 made of titanium, and an outer tube 18 made of copper or a copper alloy (for example, 1O%Ni90%Cu) is disposed outside the fin tube 17.

The fin tubes 17 are arranged radially and have a large number of fin plates 21 each having an uneven surface, and a support tube 22 that supports the fin plates 21 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 a fin tube 17 made of aluminum 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
Assume that linear unevenness is formed in the drawing direction as shown in the figure. First, an outer tube 18 made of copper is attached to the outside of the fin tube 17. 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 mm.

Next, these are passed through a die to reduce the diameter by about 5 mm if the outer diameter of the outer tube is 60 mm. This brings the outer tube 18 into close contact with the fin tube 17.

Then, the inner tube 16 is inserted inside the fin tube 17, but its dimensions are adjusted so that there is a gap of about 1 to 2 mm between the outer diameter of the inner tube 16 and the inner diameter of the fin plate 21. Select.

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 51 degrees. This brings the fin plate 21 into contact with the inner tube 16 in a compressed state, thereby improving the contact between the fin plate 21 and the inner tube 16 and improving thermal conductivity.

Next, the end structure of the heat exchanger 15 will be explained with reference to FIG. It is attached to the outer tube 18 by welding at a portion 25, and one end of a reducer 26 made of copper or a prepared alloy is attached to the other end 25 and welded to the other end 25.

A ring 27 is attached to the other end of the reducer 26, and the inner tube 16 is passed through the ring 27. This ring 27 has a titanium tube 28 inside,
Made of titanium copper clad with copper tube 29 on the outside,
Copper is completely removed from the part 30 to be welded to the titanium inner tube 16 on the inside, allowing titanium to titanium and copper to copper to be welded to achieve a completely hermetically sealed joint.

When using this heat exchanger 15, seawater or the like is passed through the inner tube 16, and a refrigerant (for example, Freon gas) is caused to flow into the outer finned tube 17 from the T-joint 23. In this case, since the surface area of the fin plate 21 with the unevenness is increased, the heat transfer efficiency is improved, and the fin plate 21 and the provided unevenness are formed parallel to the traveling direction of the refrigerant. Therefore, fluid resistance can be reduced.

In addition, the end is made of copper (
or copper alloy) and titanium, the entire structure is completely sealed and has a long service life.

1 In addition, in the above manufacturing method, first the fin tube was placed in the outer tube to reduce the diameter, and then the inner tube was placed in the reduced diameter fin tube to further reduce the diameter. to reduce the diameter,
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.

〔Effect of the invention〕

As is clear from the above description, in the heat exchanger according to claim 1, unevenness is formed on the fin plate disposed on the outside of the inner tube, and the fin plate is in contact with the inner tube in a suppressed state. Therefore, 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.

In addition, since the outer tube made of a metal with good corrosion resistance and weldability is closely placed on the outside of the finned tube manufactured by Aruryu, it is possible to protect the inner finned tube made of aluminum. A joint can be easily welded to the end.

In the heat exchanger according to claim 2, the outer tube is made of copper and the joints at the ends are made of copper, and the titanium-copper crund is used in the middle to connect it to the inner tube made of titanium. Since sealing can be achieved by welding titanium to titanium and copper to copper, manufacturing is inexpensive and furthermore, it has become possible to achieve complete sealing.

Further, in the method for manufacturing a heat exchanger according to claims 3 and 4, since the fin tube is made of aluminum, it is possible to easily manufacture a fin tube having long fin plates, and furthermore, it is possible to easily manufacture a fin tube having long fin plates. By passing it through the die, the pressing force of the fin plate attached to the inner tube increases, improving heat transfer efficiency, and the pressing force of the reduced diameter outer tube is transmitted to the fin tube. Figure 1 is a sectional view of the main part of a heat exchanger according to an embodiment of the present invention.
Figure 2 is a plan view of the heat exchanger, Figure 3 is a side view of the heat exchanger, Figure 4 is a partial sectional view of the heat exchanger, and Figure 5 shows the manufacturing process of the heat exchanger. The flowchart and FIG. 6 are sectional views of main parts of a conventional heat exchanger.

[Explanation of symbols]

Claims (4)

[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. a tube, and an outer tube made of a metal with good corrosion resistance and weldability, which is disposed in close contact with the outside of the finned tube and has an inlet and an outlet for the refrigerant at both ends, respectively. A heat exchanger characterized in that the plate has irregularities formed on its surface and is compressed in the radial direction and pressed against the inner tube. (2) The outer tube is a copper tube, and copper fittings are connected to both ends of the outer tube, and a titanium-copper cladding is used in the middle to seal the fitting and the inner tube made of titanium. 2. The heat exchanger according to claim 1, wherein the heat exchanger is closely joined by welding. (3) Prepare in advance a titanium inner tube with a predetermined diameter, an aluminum fin tube with radially formed fin plates inside, and a copper or copper alloy outer tube, and first place the fin tube inside the outer tube. The tube is charged and passed through a die to reduce its diameter, and then the inner tube is inserted into the reduced diameter fin tube with a gap left inside, and the entire tube is passed through a die to further reduce its diameter. , a method for manufacturing a heat exchanger, characterized by joining predetermined joints to both ends. (4) Prepare a titanium inner tube with a predetermined diameter, an aluminum fin tube with radially formed fin plates inside, and a copper or copper alloy outer tube, and first insert the inner tube into the fin tube. The diameter of the fin plate is reduced by passing it through a die, and the fin plate is pressed against the inner tube.
Next, this reduced diameter finned tube is charged into an outer tube, passed through a die to press the outer tube against the finned tube, and after that, joints are joined to both ends of the heat exchanger manufacturing method. .