JP3356151B2 - Fin tube type heat exchanger and refrigeration and air conditioning system using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a refrigerant and air, etc.
The present invention relates to a fin tube type heat exchanger for exchanging heat between two fluids, and a refrigeration / air conditioning apparatus such as a refrigerator or an air conditioner provided with the heat exchanger.

[0002]

2. Description of the Related Art FIGS. 20 and 21 are an external view and a sectional view of a conventional plate fin having no slit and having a slit. FIG. 23 is a plan view and a sectional view of a conventional heat exchanger. This heat exchanger is generally called a fin tube type, and is disposed at regular intervals and has plate fins 1 through which gas (air) flows, and is inserted at a right angle into each plate fin 1 to transmit a refrigerant therein. Some of the heat transfer tubes 6 are provided with a group of slits on a plate-like fin surface between adjacent heat transfer tubes 6 in a stepwise direction (a direction perpendicular to the gas passing direction). The slit group is located such that the side end of the slit 12 faces the wind direction, and the effect of updating the velocity boundary layer and the temperature boundary layer of the air flow at the side end can be expected.
It is said that heat transfer is promoted and the heat exchange capacity is increased.
FIG. 22 is an enlarged view of the fin collar 20 in the plate fin 1 of FIGS. The fin collar is a folded portion from the fin collar root, which is the bending start point of the fin tip, to the fin collar refrea, which is the fin tip. In FIG. And the fin collar base 4, and the fin collar refrea 2 and the fin collar base 4 are bent. The fin collar intermediate portion 3 has a linear shape. By laminating a large number of the plate fins 1 and inserting the heat transfer tube 6 into the fin insertion portion, and then inserting a tube expanding ball,
The fin collar 20 and the heat transfer tube 6 can be brought into close contact. FIG. 23 shows a fin tube type heat exchanger after expansion. As shown in FIG. 23, the fin collar 20 and the heat transfer tube 6
The heat exchange between the fins 1 (air) and the heat transfer tubes 6 (refrigerant) becomes possible by the close contact between the fins. Moreover, the fin collar refrea portion 2 of the fin collar 20 prevents the fins 1 from overlapping each other at the time of expanding the tube, which is called the Abeck phenomenon.

As described above, in the fin tube type heat exchanger, heat is exchanged between the fin 1 and the heat transfer tube 6 by bringing the fin collar 20 and the heat transfer tube 6 into close contact with each other. Has a thermal resistance. This is called contact thermal resistance, and the reciprocal thereof is called contact heat transfer coefficient αc. The relationship between the contact heat transfer coefficient αc and the heat transfer coefficient K between the air and the refrigerant in the heat exchanger is as follows. αo = Ao / (Ap + ψAf) / αa + Ao / Ap / αc (Equation 1) K = 1 / (1 / αo + Ao / Ai / αi) (Equation 2) Here, heat of fin-air The transfer rate is αa, the heat transfer coefficient of the refrigerant in the heat transfer tube is αi, the heat transfer coefficient outside the heat transfer tube is αo, the fin heat transfer area is Af, the heat transfer area outside the tube is Ao, and the heat transfer area in the tube is A.
i, Fin efficiency is ψ. From the above equation, as αc increases, the heat transfer rate increases. Note that the contact heat transfer coefficient αc is determined by the degree of close contact between the fin collar 20 and the heat transfer tube 6, and αc increases as the area of the contact portion and the surface pressure increase. Therefore, as shown in FIG. 22, it has been considered that the middle portion of the fin collar is straight, and that the longer the length, the larger the area of the contact portion and the higher the αc.

[0004]

However, in the fin collar 20 of the conventional fin tube type heat exchanger, according to the expansion method shown in FIG. 2, the straight fin collar intermediate portion 3 buckles and expands. Then, the intermediate portion of the fin collar floats from the heat transfer tube, and only the fin collar 20 and the heat transfer tube 6 near the fin collar refrea portion and the base portion.
However, there was a problem in that sufficient heat exchange performance could not be obtained due to no contact.

[0005] In addition, when a conventional tubing is expanded, a fin collar 20 is used.
There is a problem that a large stress concentration is generated in a portion where the heat transfer tube 6 and the heat transfer tube 6 are in contact with each other, and fin collar cracks are easily caused, the contact heat transfer coefficient αc is reduced, and sufficient heat exchange performance cannot be obtained.

The present invention has been made to solve the above-mentioned problems of the conventional fin collar, and a first object of the present invention is to optimize the shape of the fin collar so as to reduce the area of the contact portion. And contact pressure to increase the contact heat transfer coefficient αc
And to obtain a heat exchanger having a high heat exchange capacity.

A second object of the present invention is to optimize the adhesion ratio of the fin collar (= (fin collar diameter dfa after expansion-fin color diameter dfb before expansion) / fin collar diameter dfb before expansion). Accordingly, an object of the present invention is to prevent a fin collar from cracking, improve the contact heat transfer coefficient between the fin collar and the heat transfer tube, and obtain a heat exchanger having a high heat exchange capacity.

A third object of the present invention is to provide a refrigeration / air-conditioning apparatus having high energy efficiency by providing a heat exchanger having a high heat exchange capacity.

[0009]

A fin tube type heat exchanger according to the present invention comprises: a plurality of heat transfer tubes arranged in parallel;
A plate fin orthogonal to the heat transfer tube,
The shape of the fin collar in which the heat transfer tube is inserted in the plate fin and convex in the heat transfer pipe side, fin tube contacting the curved surface portion of the fin collar and the heat transfer tube
Type heat exchanger, wherein the fin collar has three or more tracks.
Bend R and connect each bend R smoothly.
And make the fin collar shape convex on the heat transfer tube side as a whole,
This is to prevent the trait portion from being present .

Further, a plurality of heat transfer tubes arranged in parallel,
Plate fins orthogonal to the heat transfer tubes,
In the plate fin, the filter through which the heat transfer tube is inserted
The shape of the collar is convex to the heat transfer tube side, and the heat transfer tube and the
Fin tube type that comes into contact with the curved surface of the fin collar
A heat exchanger, wherein the fin collar is provided with three or more bends R, and a straight portion is provided between any of the bends R.
And make them connect smoothly, and overall
The convex shape is made convex toward the heat transfer tube side .

Also, among the three or more bends R, the bend R1 of the fin collar refrea portion and the bend R of the intermediate fin collar portion
2. The bending R3 at the root of the fin collar is such that R2> R1 and R2> R3.

If the definition of the adhesion ratio Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition 0.5 ≦ Em ≦ 3.0 is satisfied. .

The plate fins have radii R7 and R8 respectively at a fin collar refrea portion and a fin collar root portion of a fin collar through which the heat transfer tube is inserted.
The two bends R are attached, and the respective bends R are connected smoothly, so that the fin collar shape is entirely convex on the heat transfer tube side.

Further, the straight portion does not exist between the radii R7 and R8, and further, with respect to the fin pitch Fp, R7 + R8 = Fp and R7> R8.

Also, a plurality of heat transfer tubes arranged in parallel,
Plate fins orthogonal to the heat transfer tubes,
In the plate fin, the filter through which the heat transfer tube is inserted
The shape of the collar is convex to the heat transfer tube side, and the heat transfer tube and the
Fin tube type that comes into contact with the curved surface of the fin collar
A heat exchanger, wherein the fin collar comprises a single R
The overall shape of the fin collar is convex to the heat transfer tube side,
Make sure there are no traits
In addition, this single bending R satisfies 2R = Fp with respect to the fin pitch Fp .

If the definition of the adhesion ratio Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition 1.0 ≦ Em ≦ 3.0 is satisfied. .

In the fin collar, an intermediate portion between the fin collar refrea portion and the fin collar root portion is formed to have a maximum protrusion toward the heat transfer tube.

Further, the fin collar is formed by using a drawless processing method.

Further, the heat transfer tube is an elliptic tube.

The heat transfer tube includes a plurality of heat transfer tubes arranged in parallel with each other and plate fins orthogonal to the heat transfer tubes. The plate fin has a fin collar through which the heat transfer tube is inserted. The heat transfer tube is expanded by inserting an expansion ball toward the root of the fin collar.

Further, in the refrigeration / air-conditioning apparatus according to the present invention, a refrigerant is used as a working fluid flowing in the heat transfer tube, and a compressor, a condenser heat exchanger, a throttle device, and an evaporator heat exchanger are sequentially connected to form a refrigerant circuit. And a blower for generating an air flow between the plate fins, and the fin tube type heat exchanger according to any of the above.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 (1) Fin Collar Shape in Fin-Tube Heat Exchanger FIG. 1 is a cross-sectional view showing a cross-sectional shape of a fin collar before expansion of plate fins used in a fin tube heat exchanger according to Embodiment 1 of the present invention. FIG. Other shapes and external views of the plate fin are the same as those in FIG. 20 or FIG.

The heat exchanger of the present embodiment includes a plurality of heat transfer tubes 6 arranged in parallel and a large number of plate fins 1 orthogonal to the heat transfer tubes 6 as described in the section of the prior art. (See FIG. 23).
Heat exchange is performed between the refrigerant flowing through the heat transfer tube 6 and the air flowing through the air flow passage between the fins 1 to act as an evaporator or a condenser. In this embodiment, the pitch Fp of the fins 1 in the stacking direction is Fp = 0.00
12m, fin thickness Ft = 0.0001m, step pitch Dp = 0.0
20m, the row pitch is Lp = 0.013m, the number of rows is N = 2, the diameter of the heat transfer tube before expansion is dob = 0.007m, and the diameter after expansion is doa = 0.00735m. The expansion ratio Ek is defined as follows. Ek = (outside diameter of heat transfer tube after expansion−outside diameter of heat transfer tube before expansion) / outside diameter of heat transfer tube before expansion (Equation 3) In this embodiment, the expansion ratio is Ek = 5.0. The fin collar diameter before expansion is dfb = 0.00725m, and the fin collar diameter after expansion is dfa = 0.00735m. Note that both dfb and dfa are the shortest distances of the cylindrical shape. The definition of the adhesion ratio Em is as follows. Em = (fin collar diameter after expansion-fin collar diameter before expansion) / fin collar diameter before expansion ... (Equation 4) In this embodiment, the adhesion rate is Em = 1.38.

According to the present embodiment, the fin collar 20 is provided with three bends R (the fin collar refrea portion 2, the fin collar intermediate portion 3, and the fin collar root portion 4). is there. The curved portions of the fin collar refrea portion 2, the fin collar intermediate portion 3, and the fin collar root portion 4 are always convex toward the heat transfer tube 6 and are smoothly connected to each other. In the present embodiment, the curvature R of the fin collar refrea portion 2 is R1 = 0.006 m,
The curvature R of the intermediate fin collar 3 is R2 = 0.0013 m, and the curvature R of the fin collar base 4 is R3 = 0.0004 m.

FIG. 2 is a sectional view showing a state of expansion of the fin tube type heat exchanger. In FIG. 2, reference numeral 5 denotes an expansion tube for expanding the heat transfer tube 6 from the inside, and reference numeral 40 denotes an expansion direction in which the expansion tube 5 moves. FIG. 3 shows a stress state and a fin collar shape in an initial stage of tube expansion when a conventional fin collar is used. As shown in FIG.
The fin collar 20 and the heat transfer tube 6 come into close contact with each other by inserting the fin collar, and when the conventional fin collar is used, the maximum tensile stress 7 is applied inside the fin collar base 4 and the maximum compression is applied to the heat transfer tube 6 side. A stress 8 is generated and a bending moment 9 is generated.

FIG. 4 shows the state of stress and the shape of the fin collar at the end of expansion when a conventional fin collar is used. The fin collar buckles in the direction opposite to the heat transfer tube 6 due to the bending moment 9. Therefore, the contact area between the fin 1 and the heat transfer tube 6 is only two points near the fin collar base 4 and the fin collar refrea 2. In addition, a tensile stress concentration inside the fin collar is observed, and the fin collar is very easily broken.

FIG. 5 shows a fin collar 20 according to this embodiment.
5 shows a stress state and a fin collar shape in an initial stage of pipe expansion in the case of using. In this case as well, a maximum tensile stress 7 is generated inside the fin collar base portion 4 and a maximum compressive stress 8 is generated on the heat transfer tube 6 side. However, the contact with the heat transfer tube 6 starts from the curved surface portion of the fin collar intermediate portion 3. Low stress concentration and small bending moment. Also, since the fin collar refrea section 2 and the fin collar base section 4 and the fin collar intermediate section 3 are smoothly connected throughout,
Stress concentration hardly occurs throughout.

FIG. 6 shows the stress state and the fin collar shape at the end of the expansion when the fin collar of the present embodiment is used. The contact area between the heat transfer tube 6 and the heat transfer tube 6 is also very large as compared with the conventional case. Further, since the degree of stress concentration is small, fin collar cracks and the like are unlikely to occur. Especially fin color 2
0, the vicinity of the middle between the fin collar refrea portion 2 and the fin collar root portion 4 is the largest convex to the heat transfer tube 6 side.
0 becomes difficult to buckle.

FIG. 7 shows the shape of the fin tube type heat exchanger using the fin collar shape according to the present embodiment after expansion, and the current contact surface pressure at a position from the origin in the figure.
The surface pressure ratio of the present embodiment with respect to the case of 100 is shown. When expanding the conventional fin collar shape (FIG. 22), as described above, the fin collar intermediate portion 3, which is a straight portion before expansion, buckles and becomes a fin collar shape that is convex in the heat transfer tube 6 direction. The fin collar 20 and the heat transfer tube 6 contact only in the vicinity of the portion 4 and the fin collar refrea portion 2. On the other hand, in the case of the fin collar shape according to the present embodiment, buckling does not occur, and the contact area is greatly increased. The average value of the contact pressure at the contact portion is almost the same as that of the conventional fin collar.

Next, a method for obtaining the contact heat transfer coefficient αc from the contact surface pressure and the contact area will be described. The heat transfer coefficient αcl at the portion where the fin collar and the heat transfer tube are in contact is shown below. αcl = 5.83 × 109 / (1 / λ1 / + 1 / λ2) × 0.6 × P × 9.8 / H + 106λf / (δ1 + δ2) (Equation 5) where λ1 is the thermal conductivity of the fin collar (aluminum)
[W / (m2K)], λ2 is the thermal conductivity of the heat transfer tube (copper) [W / (m2K)], P
Is the surface pressure [kgf / mm2], H is the hardness of the copper [kgf / mm2], λf is the thermal conductivity of the intervening material between the contact surfaces [W / (m2K)], and δ1 is the maximum roughness of the fin collar Height [μm], δ2 is the maximum height [μm] of the roughness of the heat transfer tube (copper). In this embodiment, the following values are used. λ1 = 2
37 W / (m2K), λ2 = 398 W / (m2K), H = 369 kgf / mm2, λf
= 26.13 × 10 −3 W / (m2K), δ1 = 10 μm, δ2 = 0.29 μm.
In addition, the total contact heat transfer coefficient αc of the contacting part and the non-contacting part is as follows. αc = ∫ (x × αcl (x)) dx / Fp (Equation 6) where x is the distance [m] from the origin in FIG. 7, αcl (x) is the heat transfer coefficient at x, and Fp is Fin pitch [m]. The integration interval is from 0 to 0.0012 [m]. In this way, when the contact heat transfer coefficient αc between the conventional fin collar and the fin collar according to the present embodiment is calculated, the conventional fin collar (FIG. 2)
The contact heat transfer coefficient according to 2) is αc = 10000 [W / (m2K)], and the contact heat transfer coefficient according to the present embodiment (FIG. 1) is αc = 27000 [W / (m2K).
K)]. Αc according to the present embodiment (FIG. 1) is improved about 2.7 times as compared with the conventional fin collar.

FIG. 8 shows that when the adhesion ratio Em is changed,
This figure shows the ratio of αc due to the fin collar shape of the present embodiment when the maximum value of the contact heat transfer coefficient αc according to the conventional fin collar shape is 100%. In the conventional fin collar, as the contact ratio increases, the contact surface pressure and the contact area increase, and αc increases up to about Em = 1. As the adhesion rate is further increased, the contact area increases, but the stress value at the fin collar base 4 increases, causing cracks and reducing αc. Similarly, in the fin collar of the present embodiment, as the contact ratio increases, the contact surface pressure and the contact area increase, and αc increases to about Em = 1. Even when the adhesion rate is further increased, as shown in FIG. 6, since the stress of the fin collar base portion 4 is smaller than that of the conventional fin collar, the fin collar is less cracked, and the Em is higher than that of the conventional fin collar. Maintain high αc. According to FIG. 8, the adhesion ratio is maximum around Em = 1.0, and within 20 within the range of 0.5 ≦ Em ≦ 3.0, the contact heat transfer coefficient αc is sufficiently large.

Although a large radius is attached to the fin collar intermediate portion 3 in FIG. 1, a conventional fin collar (FIG. 22)
There is also a method to bend the straight part of. That is, as shown in FIG. 9, the fin collar Rifurea unit 2 to the fin collar 20, with the two bending R of each fin collars root 4 radius R4, R 6, when the angle of the bent portion 11, theta, 90 ° ≦ θ <180 °, a bend R5 is provided at the apex, and the overall fin collar shape is convex toward the heat transfer tube 6 side.
The space between the top and the fin collar base 4 and the fin collar refrea 2 is straight. Also, θ is 90 ° in order to suppress cracking of the fin color refrea portion 2.
This is effective. By doing so, it is possible to avoid difficulties in providing a large radius of the fin collar middle portion during manufacturing. In addition, the presence of the straight portion between the Rs can prevent the Rs from affecting each other at the time of manufacturing and distorting the shape. When this contact heat transfer coefficient αc was calculated by the above equation, it was about 1.8 times.

Further, in the present embodiment, a circular tube is used as the heat transfer tube. However, even when the heat transfer tube has an elliptical shape and a flat tube, the same effect can be obtained when the fin collar shape of the present embodiment is used.

The heat exchanger using the fin collar according to the present embodiment has the same effect even when the fin slit pattern changes.

Further, in this embodiment, aluminum is used for the fins and copper is used for the heat transfer tube. However, when this material is changed to another metal, the effect is not changed.

FIG. 10 is a sectional view showing the steps of the fin collar molding method according to the present invention. The forming method in FIG. 10 is generally called a drawing processing method.

Hereinafter, the steps of the manufacturing method will be sequentially described. A conical large or columnar shallow container portion 51 having a bottom surface larger than the opening diameter of the through hole with a collar formed in the shape of a metal plate is formed [step (a)]. Is performed while the height is gradually increased while reducing the diameter [step (b), (c) and (d)]. The container portion 51 having been subjected to the drawing process to have a predetermined height is subjected to a perforating process and a burring process to form a collar 52 [step (e)]. 2 (Step (f)).

According to the manufacturing method shown in FIG. 10, since a colored through hole having a high color can be formed, the curvature of the curved surface can be increased, and a fin collar having a smooth curvature can be obtained. Will be possible.

FIG. 11 is a sectional view showing the steps of another fin collar molding method according to the present invention. The forming method in FIG. 11 is generally called a drawless processing method or an ironing processing method.

Hereinafter, the steps of the manufacturing method will be sequentially described. Drilling and burring processes are performed on the metal plate-shaped pair, and a perforated hole 54 whose peripheral edge is surrounded by the protruding piece 53.
[Step (a)], and then, while increasing the opening diameter of the perforated hole 54, extend the projecting piece 53 while squeezing, and perform ironing processing to form the collar 52 of a predetermined height [(b) ( Step c)). Such ironing processing,
Usually, it is performed by squeezing the protruding piece 53 or the collar 52 by the outer wall surface of the punch and the inner wall surface of the die. In FIG. 11, the ironing process is performed in two stages, and the diameters of the punch and the die used in each stage are different. The collar 52 of a predetermined height obtained in this manner is bent at its tip to form the fin collar refrea portion 2 [step (d)].

In the drawing process of FIG. 10, the fin collar can be made higher. However, the diameter of the container portion 51 is reduced during the drawing process, so that concentric dents occur near the obtained fin collar 20. Or wrinkles may be formed at both ends of the metal plate, and the entire fin may be warped or twisted. Therefore, dents, wrinkles, warpage, and stress concentration may occur in the torsion portion, and the effect of the present invention may not be sufficiently obtained. However, according to the manufacturing method of FIG. 11, the curved surface of the fin collar can be smoothed. It is possible to solve the above problem and sufficiently exhibit the effects of the present invention.

Embodiment 2 FIG. 12 shows the shape of the plate fin before expansion according to the embodiment of the present invention.

FIG. 12 is an enlarged view of the cross section of the fin collar in the present embodiment. The external view of the present embodiment is the same as FIG. 20 or FIG. In this embodiment, the pitch Fp of the fins 1 in the stacking direction is Fp = 0.0012m, the fin thickness Ft = 0.0001m, the step pitch is Dp = 0.020m, the row pitch is Lp = 0.013m, and the number of rows is N = 2. The diameter of the heat transfer tube before expansion is dob = 0.007m, and the diameter after expansion is doa = 0.00735m.
The expansion ratio Ek is defined as follows. Ek = (outside diameter of heat transfer tube after expansion−outside diameter of heat transfer tube before expansion) / outside diameter of heat transfer tube before expansion (Equation 7) In this embodiment, the expansion ratio is Ek = 5.0. The fin collar diameter before expansion is dfb = 0.00725m and dfa = 0.00735m. The definition of the adhesion ratio Em is as follows. Em = (fin collar diameter after expansion-fin collar diameter before expansion) / fin collar diameter before expansion ... (Equation 8) In this embodiment, the adhesion rate is set to Em = 1.38.

In this case, the fin collar is provided with two curved portions, a fin color re-flare portion (R7) 2, and a fin collar root portion (R8) 4, and is a specification having no linear portion. The fin collar refrea portion 2 and the fin collar root portion 4 which are the curved portions are always convex toward the heat transfer tube 6 and are smoothly connected. In addition, the fin collar 20 is provided with two curved portions, and has no linear portion. Also,
R7 + R8 = Fp (Equation 9) needs to be satisfied in order to connect two Rs smoothly and not to form a straight line portion. By creating a fin collar with two bending Rs in this way, it is not necessary to create a large R in the middle of the fin collar as shown in the first embodiment, which is superior to the first embodiment in manufacturing. There is. In this embodiment, the curvature R of the fin collar refrea portion is R4 = 0.
0006m, and the curvature R of the fin collar base is R5 = 0.0006m. In this case, the fin collar is formed by a single R (= 0.0006 m).

FIG. 13 shows the stress state and the fin collar shape at the end of the expansion when the fin collar of this embodiment is used, but does not buckle unlike the conventional fin. Therefore, the contact area between the fin and the heat transfer tube is larger than that of the conventional fin collar.

FIG. 14 shows the shape after expansion of the fin tube type heat exchanger using the fin collar shape according to the present embodiment, and the current contact surface pressure at a position from the origin in the figure.
The surface pressure ratio of the present embodiment when 100 is set is shown. When expanding the conventional fin collar shape (FIG. 22), as described above, the straight portion 3 before the expansion expands and becomes a fin collar shape convex in the direction of the heat transfer tube, and only the root portion 4 and the refrea portion 2 have the fin collar. 20 and the heat transfer tube 6 do not contact. On the other hand, in the case of the fin collar shape of the present embodiment, buckling does not occur, and the contact area increases, although not as large as the fin collar of the first embodiment. Further, the average value of the contact pressure of the contact portion is larger than that of the conventional fin collar. Further, when the contact heat transfer coefficient αc by the conventional fin collar and the fin collar according to the present embodiment is calculated by using the equation for calculating the contact heat transfer coefficient αc shown in the first embodiment, the αc according to the present embodiment is obtained. The heat transfer coefficient was improved about 2.0 times as compared with the conventional fin collar.

FIG. 15 shows the relationship between the contact heat transfer coefficient αc of the present embodiment and the maximum value of the contact heat transfer coefficient αc of the conventional fin collar shape of 100% when the adhesion ratio Em is changed. It shows the ratio. In the conventional fin collar, as the contact ratio increases, the contact surface pressure and the contact area increase, and αc increases up to about Em = 1. As the adhesion rate is further increased, the contact area increases, but the stress value at the fin collar base 4 increases,
Cracks occur and αc decreases. Similarly, in the fin collar of the present embodiment, as the contact ratio is increased, the contact surface pressure and the contact area are increased, and αc is significantly improved up to Em = 1. Even when the adhesion rate is further increased, the crushing of the R portion increases and the contact area increases, so
Improves. Therefore, the value of the adhesion ratio Em having the maximum value is larger than in the case of the first embodiment. In the case of the present embodiment, if the range is 1.0 ≦ Em ≦ 3.0, the maximum value is within 20 and the contact heat transfer coefficient Em is sufficiently large.

In the present embodiment, a circular tube is used as the heat transfer tube. However, even when the heat transfer tube has an elliptical shape or a flat tube, the same effect as when the fin collar shape of the present embodiment is used can be obtained.

FIG. 12 shows a fin collar refrea section.
The case where two Rs of R7 and the fin collar base R8 are made equal, that is, the case where the fin collar is composed of one R is shown, but when this R7 and R8 are not equal, if R7> R8, the fin is expanded at the time of expansion. The overlap between the fin and the fins is reduced, and the same effect as when the fin collar shape of the present embodiment is used can be obtained.

The heat exchanger using the fin collar according to the present embodiment has the same effect even when the fin slit pattern changes.

Further, in this embodiment, aluminum is used for the fins and copper is used for the heat transfer tube. However, when this material is changed to another metal, the effect is not changed.

Embodiment 3 FIG. FIG. 16 shows a configuration of a fin tube type heat exchanger according to Embodiment 3 of the present invention. In FIG. 16, (a)
Is a plan sectional view when viewed from a direction perpendicular to the fin 1, and (b) is a partial side sectional view when the BB plane in FIG. In this embodiment, the cross-sectional shape of the heat transfer tube 6 is an elliptic tube. In addition, heat transfer tube 6
The slits 53, 54 and 55 formed by cutting and raising the fin 1 in the stepwise direction (the direction perpendicular to the direction in which gas passes) are formed on the fins 1 between the fins 1 and the slits formed only by cutting and raising only the legs. 56 and 57 are provided along the gas flow direction, respectively, and constitute a slit group. Note that other shapes are the same as those of the first and second embodiments. In the drawings, the same or corresponding parts as those of the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 16, the distance a ₁ = 0.0025 m from the leading edge of the fin 1 to the heat transfer tube 6, the distance a ₂ = 0.00489 m from the trailing edge of the fin 1 to the heat transfer tube 6, and the major axis length da of the heat transfer tube 6 = 0.01301m, short axis length db of heat transfer tube 6 = 0.00377m, step pitch Dp of heat transfer tube 6 = 0.
0204m, row pitch Lp of heat transfer tubes 6 = 0.005m, fin pitch Fp
= 0.0012m, fin thickness Ft = 0.0001m, fin width L = 0.0254m
It is.

When the heat transfer tube 6 is an elliptic tube, the contact pressure on the fin collar 20 differs between the short axis side and the long axis side during expansion. Therefore, the stress concentration on the fin collar 20 also varies depending on the location, but it is difficult to partially change the strength of the fin collar 20. Therefore, it is necessary to provide a fin collar capable of coping with a certain degree of stress difference. According to the fin collar of the present embodiment, since stress concentration hardly occurs and buckling and breakage hardly occur, the fin collar is suitable for such an elliptic heat transfer tube.

Further, since the adhesion rate and the contact heat transfer coefficient after the expansion are good, the heat exchange efficiency on the long axis side and the short axis side of the elliptic tube is good. In addition, the elliptic tube can improve the heat exchange capacity and reduce the ventilation resistance as compared with the round tube. Conventionally, even if an attempt was made to improve the heat exchange capacity of an elliptical tube, the contact area with the fin collar could not be sufficiently secured, and the effect could not be exerted. The effect of the ability improvement can be fully exhibited. The elliptical tube shape is not limited to that shown in FIG. 16, and the same effect can be obtained with other elliptical shapes.

Embodiment 4 (2) Expansion Method of Fin-Tube Heat Exchanger FIG. 17 shows a method of expanding the fin-tube heat exchanger according to the present embodiment, and is a cross-sectional view of a stage in the middle of expansion. In the case of the present embodiment, the expansion tube 5 is a fin collar 20.
From the fin collar refrea section 2 to the fin collar base section 4.
Further, in the present embodiment, the specifications of the plate fins 20 are similar to the plate fins described in the related art.

FIG. 18 shows the shapes of the fin tube type heat exchanger after expansion according to the present embodiment and the conventional expansion method, the contact length between the fin collar 20 and the heat transfer tube 6, and the surface pressure. I have. In a normal pipe expanding method, the pipe expanding ball is inserted from the base of the fin collar toward the fin collar refrea (FIG. 2 ). FIG. 18 shows that the buckling of the fin 1 is reduced and the contact area between the fin collar 20 and the heat transfer tube 6 hardly changes by reversing the insertion direction of the expanding ball 5 as in the present embodiment. This indicates that the surface pressure increases.

Using the equation for determining the contact heat transfer coefficient αc shown in the first embodiment,
Αc according to the present embodiment is about 1.3 times.

In this embodiment, a circular tube is used as the heat transfer tube. However, even when the heat transfer tube has an elliptical shape or a flat tube, the same effect as when the fin collar shape of the present embodiment is used can be obtained. Of course, the tube expanding method of the present embodiment is also applicable to the fin collar shapes of the first, second, and third embodiments.

The heat exchanger using the fin collar according to the present embodiment has the same effect even when the slit pattern of the fin changes.

Furthermore, in this embodiment, aluminum is used for the fins and copper is used for the heat transfer tube. However, when this material is changed to another metal, the effect is not changed.

Embodiment 5 FIG. 19 is a conceptual diagram showing a refrigerant circuit diagram and a refrigerating air conditioner including a blower. The refrigerant circuit shown in the figure is configured by sequentially connecting a compressor 31, a condensation heat exchanger 32, a throttling device 33, and an evaporation heat exchanger 34 by refrigerant piping. Of course, a four-way valve for cooling and heating operation may be provided. Reference numeral 35 denotes a blower for generating an airflow passing through the condensing heat exchanger 32 and the evaporating heat exchanger 34, and reference numeral 36 denotes a blower motor for driving the blower 35. Embodiment 1 described above,
By using the fin tube type heat exchangers of 2, 3 and 4 for the condensing heat exchanger 22 and / or the evaporating heat exchanger 24, a refrigeration / air-conditioning apparatus with high energy efficiency can be realized. Here, the energy efficiency is represented by the following equation. Heating energy efficiency = indoor heat exchanger (condenser) capacity / all inputs ・ ・ ・ (Equation 10) Cooling energy efficiency = indoor heat exchanger (evaporator) capacity / all inputs ・ ・ ・ (Equation 11)

The heat exchangers described in the first, second and third embodiments and the air-conditioning and refrigeration systems using the same have the HCFC (R22) and the HFCs (R116 and R12).
5, R134a, R14, R143a, R152a, R
227ea, R23, R236ea, R236fa, R
245ca, R245fa, R32, R41, RC31
8 and several kinds of mixed refrigerants R407A, R
407B, R407C, R407D, R407E, R4
10A, R410B, R404A, R507A, R50
8A, R508B, etc.), HC (butane, isobutane,
Ethane, propane, propylene, etc., and a mixture of several kinds of these refrigerants), natural refrigerants (air, carbon dioxide, ammonia, etc., and a mixture of several kinds of these refrigerants), and a mixture of several kinds of these refrigerants, The effect can be achieved using any kind of refrigerant.

In addition, the effect can be achieved with any of refrigeration oils such as mineral oils, ester oils, alkylbenzene oils and other oils having high and low compatibility with the refrigerant. Further, although examples of air and refrigerant have been shown as working fluids, similar effects can be obtained by using other gases, liquids, and gas-liquid mixed fluids.

Although the heat transfer tube and the fin are often made of different materials, the same material such as copper is used for the heat transfer tube and the fin, and aluminum is used for the heat transfer tube and the fin. Can be attached, the contact heat transfer coefficient between the fin portion and the heat transfer tube is dramatically improved, and the heat exchange capacity is greatly improved. Also, recyclability can be improved.

[0066]

The heat exchanger according to the present invention is configured as described above, and has the following effects.

A plurality of heat transfer tubes arranged in parallel with each other, and plate fins orthogonal to the heat transfer tubes, wherein the fin collar of the plate fins through which the heat transfer tubes are inserted is formed to project toward the heat transfer tube; The heat transfer tube is brought into contact with the curved surface portion of the fin collar, and the plate
In the fin collar where the heat transfer tube in the fin is inserted
Attach three or more bends and slide each bend.
Fin collar shape on the heat transfer tube side as a whole
To make it convex and not to have a straight part ,
This has the effect of reducing the stress concentration of the fin collar, reducing deformation and destruction, and obtaining a heat exchanger having a high heat exchange capacity.

The fin collar of the plate fin into which the heat transfer tube is inserted is provided with three or more bends R, and a straight portion is provided between any of the bends R to smoothly connect them. Since the fin collar shape is convex toward the heat transfer tube side, it is possible to avoid difficulties in providing a large radius at the fin collar middle part during manufacturing, and to obtain a heat exchanger with good manufacturability and high heat exchange capacity. effective.

When the definition of the adhesion ratio Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition 0.5 ≦ Em ≦ 3.0 is satisfied. This has the effect of increasing the contact heat transfer coefficient and obtaining a heat exchanger having a high heat exchange capacity.

Further, the plate fins have radii R7 and R8 at the fin collar refrea portion and the fin collar root portion of the fin collar through which the heat transfer tube is inserted.
The two bends R are connected, and each bend R is connected smoothly. The overall fin collar shape is convex on the heat transfer tube side, so stress concentration can be reduced, manufacturability is good, and heat exchange capacity is high. There is an effect that a heat exchanger can be obtained.

In addition, since there is no straight portion between the radii R7 and R8, and R7 + R8 = Fp and R7> R8 with respect to the fin pitch Fp, a smooth shape is obtained. Accordingly, stress concentration can be reduced, and there is an effect that a heat exchanger having good manufacturability and high heat exchange capacity can be obtained.

[0072] Furthermore, a fin collar the heat transfer tube in the plate fins are inserted and composed of a single R, overall a convex fin collar shape the heat transfer pipe side, the Fi
If there is no straight part in the collar
Furthermore, this single bend R corresponds to the fin pitch Fp.
Since 2R = Fp , a heat exchanger having good manufacturability and high heat exchange ability can be obtained.

When the definition of the adhesion rate Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition of 1.0 ≦ Em ≦ 3.0 is satisfied. Thus, there is an effect that a heat exchanger which is easy to manufacture and has a high heat exchange capacity can be obtained.

Further, since the portion near the middle between the fin collar refrea portion and the fin collar root portion in the fin collar is formed to be the largest convex to the heat transfer tube side, the fin collar is less likely to buckle during tube expansion.

Further, since the fin collar is formed by using the drawless processing method, the curved surface shape can be smoothed, so that stress concentration is reduced and a heat exchanger having a high heat exchange ability can be obtained.

Further, since the heat transfer tube is an elliptic tube, the heat exchange capacity of the elliptic tube can be improved and the ventilation resistance can be reduced.
In addition, there is an effect that the adhesion between the elliptical tube and the fin collar can be improved.

Further, a plurality of heat transfer tubes arranged in parallel, and plate fins orthogonal to the heat transfer tubes are provided. Since the heat transfer tube is expanded by inserting the expansion tube toward the root portion of the fin collar, the contact surface pressure is increased, and there is an effect that a heat exchanger having a high heat exchange capacity can be obtained.

In the refrigeration / air-conditioning apparatus according to the present invention, a refrigerant is used as a working fluid flowing in the heat transfer tube, and a compressor, a condenser heat exchanger, a throttle device, and an evaporator heat exchanger are connected in order to form a refrigerant circuit. In the refrigeration / air-conditioning apparatus having a blower that generates an air current between the plate fins, the fin tube type heat exchanger according to any one of the above, the heat transfer performance is improved, and the energy efficiency is excellent. There is an effect that a refrigerating air conditioner can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of the present invention, and is a cross-sectional view of a fin collar portion of a plate fin.

FIG. 2 is a view showing the first embodiment and is a cross-sectional view showing a transient state of expansion of the fin tube type heat exchanger.

FIG. 3 is a diagram showing the first embodiment and is an explanatory diagram showing a stress distribution applied to the fin collar at the start of pipe expansion for a conventional fin collar.

FIG. 4 is a view showing the first embodiment and is an explanatory view showing a stress distribution applied to the fin collar at the end of the expansion of the conventional fin collar.

FIG. 5 is a diagram showing the first embodiment and is an explanatory diagram showing a stress distribution applied to the fin collar at the start of pipe expansion for the fin collar of FIG. 1;

6 is a diagram showing the first embodiment, and is an explanatory diagram showing a stress distribution applied to the fin collar at the end of the expansion of the fin collar of FIG. 1. FIG.

FIG. 7 shows the first embodiment, and is a cross-sectional view of a fin collar shape after pipe expansion and a characteristic diagram showing a contact surface pressure improvement ratio with respect to a distance in a stacking direction.

FIG. 8 is a view showing the first embodiment, wherein
FIG. 4 is a characteristic diagram showing a contact heat transfer coefficient improvement rate.

FIG. 9 shows the first embodiment, and is a cross-sectional view of the fin collar portion of the plate fin.

FIG. 10 shows the first embodiment and is a cross-sectional view showing the method for manufacturing the fin collar.

FIG. 11 shows the first embodiment and is a cross-sectional view showing the method for manufacturing the fin collar.

FIG. 12 shows the second embodiment, and is a cross-sectional view of a fin collar portion of a plate fin.

FIG. 13 is a view showing the second embodiment, and is an explanatory view showing a stress distribution applied to the fin collar at the end of the expansion of the fin collar of FIG. 1;

FIG. 14 shows the second embodiment, and is a cross-sectional view of a fin collar shape after pipe expansion and a characteristic diagram showing a contact surface pressure improvement ratio with respect to a distance in a stacking direction.

FIG. 15 shows the second embodiment and is a characteristic diagram showing a contact heat transfer coefficient improvement ratio with respect to an adhesion ratio.

FIG. 16 shows the third embodiment, and is a plan sectional view and a partial sectional view showing the configuration of the heat exchanger.

FIG. 17 is a view showing the fourth embodiment, and is a cross-sectional view showing a transient state of expansion of the fin tube type heat exchanger.

FIG. 18 shows the fourth embodiment, and is a cross-sectional view of the fin collar shape after pipe expansion and a characteristic diagram showing a contact surface pressure improvement ratio with respect to a distance in a stacking direction.

FIG. 19 shows the fifth embodiment and is a diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus.

FIG. 20 is a view showing a conventional heat exchanger, which is a partial plan view showing a state before plate fins are expanded, a side view thereof, and a fin collar sectional view.

FIG. 21 is a view showing a conventional heat exchanger, and is a partial plan view and a fin collar cross-sectional view showing a state before expansion of a plate fin.

FIG. 22 is a view showing a conventional heat exchanger, and is a cross-sectional view of a fin collar portion of a plate fin.

FIG. 23 is a view showing a conventional heat exchanger, and is a partial plan view and a side view showing a state after expansion of a fin tube type heat exchanger.

[Explanation of symbols]

1 fin, 2 fin collar refrea, 3 fin collar middle, 4 fin collar base, 5 expansion tube, 6 heat transfer tube, 7 maximum tensile stress, 8
Maximum compressive stress, 9 bending moment, 10 fin collar straight part, 11 fin collar bending part,
12 slits, 20 fin collars, 31 compressor, 32 condensation heat exchanger, 33 expansion device, 34
Evaporation heat exchanger, 35 blower, 36 motor for blower, 40 expansion direction.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Kanazawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Kazuya Aiba 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Inside Electric Machinery Co., Ltd. (72) Inventor Yoichi Hisamori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (56) References JP-A-9-329398 (JP, A) JP-A-64-27770 (JP, A (Japanese) Shokai 49-124669 (JP, U) Jiko 48-3178 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F28F 1/32 B21D 39/06 B21D 53 / 08

Claims (13)

(57) [Claims] 1. A heat transfer tube comprising: a plurality of heat transfer tubes arranged in parallel; and a plate fin orthogonal to the heat transfer tube, wherein a shape of a fin collar of the plate fin through which the heat transfer tube is inserted is convex toward the heat transfer tube. And a fin tube type heat exchanger for bringing the heat transfer tube into contact with the curved surface portion of the fin collar, wherein the fin collar is provided with three or more bends R, and each of the bends R is smoothly connected; A fin tube type heat exchanger characterized in that the fin collar shape is entirely convex on the heat transfer tube side so that a straight portion does not exist. 2. A heat transfer tube comprising: a plurality of heat transfer tubes arranged in parallel; and a plate fin orthogonal to the heat transfer tube, wherein a shape of a fin collar of the plate fin through which the heat transfer tube is inserted is convex toward the heat transfer tube side. A fin tube type heat exchanger for bringing the heat transfer tube into contact with a curved surface of the fin collar, wherein the fin collar is provided with three or more bends R, and a straight portion is provided between any of the bends R A fin-tube heat exchanger characterized in that the fin collar shape is made convex on the heat transfer tube side as a whole by connecting them smoothly. 3. The method according to claim 3, wherein, among the three or more bends R, the bend R1 of the fin collar refrea, the bend R2 of the middle of the fin collar, and the bend R3 of the base of the fin collar satisfy R2> R1 and R2> R3. The fin tube type heat exchanger according to claim 1 or 2, wherein 4. When the definition of the adhesion ratio Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition of 0.5 ≦ Em ≦ 3.0 is satisfied. The fin tube type heat exchanger according to claim 1 or 2, wherein 5. A heat transfer tube comprising: a plurality of heat transfer tubes arranged in parallel; and a plate fin orthogonal to the heat transfer tube, wherein a shape of a fin collar of the plate fin through which the heat transfer tube is inserted is convex toward the heat transfer tube side. A fin tube type heat exchanger for bringing the heat transfer tube into contact with the curved surface portion of the fin collar, wherein the fin collar has a radius R7 and
A fin tube type heat exchanger characterized in that two bends R of R8 are provided, and the respective bends R are connected smoothly, and the fin collar shape is entirely convex on the heat transfer tube side. 6. A straight portion is not present between the radii R7 and R8, and a fin pitch is further reduced.
The fin-tube heat exchanger according to claim 5, wherein R7 + R8 = Fp and R7> R8 with respect to Fp. 7. A heat transfer tube comprising: a plurality of heat transfer tubes arranged in parallel; and a plate fin orthogonal to the heat transfer tube, wherein a shape of a fin collar of the plate fin through which the heat transfer tube is inserted is convex toward the heat transfer tube side. A fin tube type heat exchanger for bringing the heat transfer tube into contact with the curved surface portion of the fin collar, wherein the fin collar is constituted by a single R,
The fin has a fin collar shape that is convex toward the heat transfer tube side so that there is no straight portion, and the single bend R is 2R = Fp with respect to the fin pitch Fp. Tube type heat exchanger. 8. When the definition of the adhesion ratio Em is Em = (fin collar diameter after expansion−fin collar diameter before expansion) / fin collar diameter before expansion, the condition of 1.0 ≦ Em ≦ 3.0 is satisfied. The fin tube type heat exchanger according to any one of claims 5 to 7. 9. The fin tube according to claim 1, wherein an intermediate portion of the fin collar between a fin collar refrea portion and a fin collar root portion has a maximum protrusion toward the heat transfer tube. Type heat exchanger. 10. A heat transfer tube comprising: a plurality of heat transfer tubes arranged in parallel; and a plate fin orthogonal to the heat transfer tube, wherein a shape of a fin collar of the plate fin through which the heat transfer tube is inserted is convex toward the heat transfer tube side. A fin tube type heat exchanger for bringing the heat transfer tube into contact with a curved surface portion of the fin collar, wherein the fin collar is formed by a drawless processing method. 11. The fin tube type heat exchanger according to claim 1, wherein the heat transfer tube is an elliptic tube. 12. A fin collar, comprising: a plurality of heat transfer tubes arranged in parallel; and plate fins orthogonal to the heat transfer tubes. The fin tube type heat exchanger according to any one of claims 1 to 11, wherein the heat transfer tube is expanded by inserting an expansion ball toward a root portion of the fin collar. 13. A refrigerant circuit is formed by sequentially connecting a compressor, a condenser heat exchanger, a throttling device, and an evaporator heat exchanger with a refrigerant as a working fluid flowing in the heat transfer tube,
In the refrigerating and air-conditioning apparatus provided with a blower for generating an air flow between the plate fins, refrigeration and air conditioning apparatus characterized by comprising a finned tube heat exchanger according to any one of claims 1 to 1 2.