JPH10277679A - Plate fin tube heat exchanger and production of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fin pitch of a plate fin generating in expanding a copper tube. SOLUTION: A plate fin tube heat exchanger is composed of a large number of laminated plate fins 21 with a fin collar 21b formed around a hole 21a through which a cooper tube 22 being passed, and the expanded copper tube 22 passed through the hole 21a in closely contact with the plate fins 21. This plate fins 21 are composed of a fin metal having, the coefficient of friction of at least 0.15 or more without oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate fin tube heat exchanger for preventing fin pitch disturbance of aluminum plate fins caused by expansion of a copper tube, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, plate fin tube heat exchangers have been manufactured as shown in FIGS. FIG. 3 is a diagram showing a state where the hairpin copper tube 2 is inserted into the hole 1a of the stacked plate fins 1 and a direction of the tube expansion. The copper tube 2 is inserted from the fin collar 1b side as shown by an arrow A in FIG. 3, and the copper tube 2 is expanded as shown by an arrow B in FIG. 1D is performed by pushing the plug 3 in the direction of arrow B from the open end of the copper tube 2 as shown in FIG.

However, when the pipe is fixed to the pipe, there is a problem that the fin pitch is easily disturbed as shown in FIG. Various factors influence the fin pitch disturbance due to the sticking of the expanded pipe, and the mechanism is as follows.

(1) When the copper tube 11 shown in FIG. 6A is expanded, the length of the copper tube 11 is reduced because the diameter of the copper tube 11 is increased as shown in FIG. 6B. When only one plate fin 12 shown in FIG. 7A is attached to the copper tube and the copper tube is expanded, the plate thickness of the fin flat portion 13 is 0.10 to 0.12 mm.
Out of plane. Since the collar root angle of the fin before expansion is 90 °, the direction of out-of-plane deformation is an obtuse angle direction. However, the collar root angle before expansion is 90 °
If smaller, the fin flat portion 13 may be deformed in the sharpening direction.

(2) When the copper tube 11 is expanded, the length is reduced as shown in FIG. 6 (B), but the fin collar height (H) at that portion does not shrink, so the fin at the unexpanded portion is not expanded. Is subjected to compressive deformation corresponding to the amount of shrinkage of the copper tube 11, and a compression reaction force is generated at the contact portion between the collars (the fin flat portion and the flared curl portion). The amount of compressive deformation and the compressive reaction force increase as the expansion of the tube proceeds. Therefore, other than the first fin, the tube is expanded (the inner diameter of the collar is expanded) while being subjected to any compressive deformation and a compressive force as a reaction force.

(3) In the initial stage of the expansion, as shown in FIG. 5A, since the amount of compressive deformation is small and the compressive reaction force is also small, the fins are deformed in a direction in which the base angle of the collar becomes obtuse. But,
As shown in FIG. 5 (B), when the amount of compression deformation and the compression reaction force increase due to the expansion of the tube, some of the fins are deformed in the opposite direction (direction in which the base angle of the collar becomes obtuse), and the fin pitch is reduced. It will be disordered. This state is generally called Abeck. Further, as shown in FIG. 5 (C), when the expansion of the tube progresses and the amount of compressive deformation and the compressive reaction force increase, all the remaining fins move in the opposite direction (the direction in which the collar root angle becomes obtuse).
It looks like there is no disturbance of the fin pitch and no abeck is generated.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. First, plate fins having a coefficient of friction of at least 0.15 or more, preferably 0.3 or more, with no oil are applied. An object of the present invention is to provide a plate-fin-tube heat exchanger that is made of a fin material and that can prevent disturbance of a fin pitch caused by tube expansion. Secondly, during the tube expanding step, compressive force is applied to the fin collar portion of the plate fin from the side where the fin collar is not formed, and the tube is expanded in that state, thereby preventing fin pitch disturbance. It is an object of the present invention to provide a method for manufacturing a plate fin tube heat exchanger that can be manufactured. Third, by setting the plate fins to at least 1.2 times the fin compression reaction force at the time of occurrence of Abeck, the base angles of the collars of all fins are sharpened and deformed, so that the plate fins are not disturbed in pitch. An object of the present invention is to provide a method for manufacturing a tube heat exchanger.

[0008]

According to a first aspect of the present invention, a plurality of laminated plate fins having a fin collar formed around a hole through which a tube is passed, and the plate fin is passed through the hole so as to be in close contact with the plate fin. A plate fin tube heat exchanger comprising: an expanded tube, wherein the plate fins have a coefficient of friction of at least 0.15 without oil.
A plate fin tube heat exchanger characterized by comprising the above fin material.

In the first invention, the coefficient of friction is determined by measuring a steel ball diameter using a Bowden-Leben type friction tester as follows:
3/16 inch, load: 0.2 kgf, sliding speed: 3.
87 mm / s, temperature: 20 ° C.

[0010] The second invention of the present application is a step of laminating a number of plate fins each having a fin collar formed around a hole through which a tube passes, a step of passing the tube through the hole, and expanding the tube from the inside to form the tube. A step of adhering the plate fins and the tube to the plate fin tube heat exchanger, wherein in the step of expanding the tube, a compressive force is applied to the fin collar portion of the plate fin from the side where the fin collar is not formed. And add
A method for manufacturing a plate-fin tube heat exchanger, characterized in that the tube is expanded in that state.

In the second invention, at least 1.1 of the fin compression reaction force at the time of occurrence of Abeck in the plate fin.
It is preferable to set it to twice or more. As a result, the base angles of the collars of all the fins are sharpened and deformed, so that a plate fin tube heat exchanger without fin pitch disturbance can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In this embodiment, FIG.
A plate-fin tube heat exchanger is manufactured through the steps shown in (A) to (H). In this embodiment, as shown in FIG. 9, between the insertion of the copper pipe in (C) and the expansion and fixation of the pipe in (E),
The main point is that a predetermined compressive force P is applied to the fin collar 21b of the copper tube 22 inserted in the hole 21a of the plate fins 21 that have been stacked before expansion. In this manner, by applying a predetermined compressive force P to the fin collar 21b before the tube expansion, the collar root angle of the plate fin 21 is sharpened and deformed from the expansion start portion, thereby preventing the fin pitch from being disturbed.

In fact, the test fin material, press forming, fin shape, and fin compression reaction force at the time of Abeck generation were set as follows, and the following fins were cut into one step, and 110 fins were formed into φ.
Insert a copper tube with a 9.52 mm inner groove, φ9.20 mm
When the tube is expanded by pushing the plug (the direction of expansion is B in FIG. 3).
Direction) and the results shown in Table 1 below were obtained.

Test fin material: Aluminum fin material for drawless and DOF, 0.11 mm, water glass-based hydrophilic surface treated fin material, press molding: φ9.52 manufactured by Hidaka Seiki
Molded with mmDOF, using volatile press oil, fin shape: 1
Flat shape with 20 rows of ribs, color height 1.2m
m, Fin compression reaction force when Abeck occurs: 40 N,
The fin compression reaction force was measured using a fin compression reaction force measurement device shown in FIG. 10 (this device is mounted on a tensile tester). FIG. 10 shows a measuring device in the case of a one-hole fin, and reference numeral 31 in the drawing denotes a fin compression reaction force measuring load cell arranged below the device. Above this load cell, a plurality of laminated aluminum fins 32 are arranged, and a copper tube 33 is inserted into a hole 32a of the aluminum fin 32, and a copper tube 33 for expanding the copper tube 33 right above the copper tube 33 is provided. An expansion tube brit 34 is arranged.

[0015]

[Table 1]

According to Table 1, the friction coefficient is 0.2,
When the compression force before expansion was 50 N at 0.3 and 0.4, it was apparent that no one out of five fin pitch disturbances occurred. In other words, the fin pitch is increased by setting the friction coefficient to be 0.15 or more and the compression force before expansion to 50N, which is larger than 1.2 times (= 48N) the fin compression reaction force (= 40N) when Abeck occurs. It has been found to prevent turbulence.

In the above embodiment, the case where the test fin material is an aluminum fin material for drawless and DOF has been described. However, the present invention is not limited to this, and other materials can be similarly applied. Further, the friction coefficient may be 0.15 or more, and the compression force may be set to at least 1.2 times or more of the fin compression reaction force at the time of occurrence of Abeck in the plate fin.

[0018]

As described above in detail, according to the plate fin tube heat exchanger of the present invention, the plate fins are made of a fin material having a friction coefficient of at least 0.15 or more without oiling, so that the tube fins can be used. Of the fin pitch caused by the expansion of the tube can be prevented. Further, according to the method of the present invention, at the time of the tube expanding step, a compressive force is applied to the fin collar portion of the plate fin from the side where the fin collar is not formed, and the tube is expanded in that state, whereby the fin is expanded. Pitch disturbance can be prevented. Further, by setting the plate fins to be at least 1.2 times the fin compression reaction force when the Abeck occurs, the collar base angles of all the fins can be sharpened and deformed, thereby preventing the fin pitch from being disturbed.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view showing a method of manufacturing a conventional plate fin tube heat exchanger in the order of steps.

FIG. 2 is an explanatory view showing how to expand a copper tube inserted into a plate fin in a conventional method for manufacturing a plate fin tube heat exchanger.

FIG. 3 is an explanatory diagram showing directions of inserting and expanding a general copper tube.

FIG. 4 is a schematic view of a micrograph showing an example of fin pitch disturbance in a conventional method for manufacturing a plate fin tube heat exchanger.

5A and 5B are schematic diagrams of a micrograph of a mechanism of generation of fin pitch. FIG. 5A is an explanatory diagram of a plate fin and a tube in a state where tube expansion is started, and FIG. FIG. 5 (C) is an explanatory view of a fin and a tube, and FIG.

FIG. 6 is an explanatory diagram showing a deformation behavior of a copper tube due to expansion.

FIG. 7 is an explanatory diagram showing a deformation behavior of a plate fin due to expansion.

FIG. 8 is an explanatory view showing a method of manufacturing the plate fin tube heat exchanger according to the present invention in the order of steps.

FIG. 9 is an explanatory view showing a method of expanding a copper tube inserted into a plate fin in the method for manufacturing a plate fin tube heat exchanger according to the present invention.

FIG. 10 is an explanatory view of a fin compression reaction force measuring device for measuring a fin compression reaction force in the present invention.

[Description of reference numerals] 21: plate fin, 21a: hole, 21b: fin collar, 22: copper tube.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshio Suzuki 3-1-1, Asahimachi, Nishibiwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside the Air Conditioning Works of Mitsubishi Heavy Industries, Ltd. Sumitomo Light Metal Industries, Ltd., Research and Development Center, Inc. Akihiro 3-1-1-12 Millennen, Minato-ku, Nagoya-shi, Aichi Sumitomo Light Metal Industries R & D Center

Claims (3)

[Claims] 1. A plate fin tube having a plurality of stacked plate fins each having a fin collar formed around a hole through which a tube passes, and an expanded tube passed through the hole so as to be in close contact with the plate fin. In the exchanger, the plate fins are made of a fin material having a coefficient of friction of at least 0.15 or more in the absence of oil. 2. A step of stacking a number of plate fins each having a fin collar formed around a hole through which a tube passes, a step of passing the tube through the hole, and expanding the tube from the inside to form the plate fin and the tube. A method of manufacturing a plate fin tube heat exchanger comprising: a step of applying a compressive force to the fin collar portion of the plate fin from the side where the fin collar is not formed during the tube expanding step, A method for manufacturing a plate fin tube heat exchanger, comprising expanding the tube in a state. 3. The method according to claim 1, wherein the compressive force is at least 1.1 of a fin compression reaction force at the time of occurrence of Abeck in the plate fin.
2. The method for manufacturing a plate fin tube heat exchanger according to claim 1, wherein the number is set to be twice or more.