JPS61159335A - Cross fin tube type heat exchanger - Google Patents

Abstract

PURPOSE:To prevent parts between fins from being wholy closed due to frost and improve the performance of heat exchange at low temperatures by partly enlarging face-to-face distance between fins by means of the form and relative position of cut-and-raised pieces. CONSTITUTION:A fin group 2 consists of a first fin 2a having a first cut-and- raised group 8a, and a second fin 2b having a second cut-and-raised group 8b, which are alternately arranged. The first cut-and-raised group 8a consists of a first cut-and-raised piece 6a which is aligned in the direction of the step of a heat exchanger 1 and a first flat piece 7a. The second cut-and-raised group 8b consists of a second cut-and-raised piece 6b which is aligned in the direction of the step of the heat exchanger 1 and a second flat piece 7b. Here, the first cut-and-raised piece 6a and the second cut-and-raised piece 6b are arranged in such a way that they are overlapped with each other in the direction of the step of the heat exchanger 1, while in the direction of row, the position of the rear end of the first cut-and-raised piece 6a is shifted to the position of the front and rear edges of the second cut-and-raised piece 6b.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cross-fin tube type heat exchanger used in air conditioners, etc., and more specifically to a heat exchanger in which a number of cut and raised pieces are bent and formed on the fin surface. It is related to.

Conventional technology Conventionally, heat exchangers used in air conditioners, etc.
A loss fin tube type heat exchanger 50 is used as shown in FIGS. That is, a large number of fins 51
The cross-fin tube heat exchanger 50 is constructed by arranging the fins 51 in parallel at predetermined intervals to form a fin group 51, and by intersecting the heat transfer tubes 62 perpendicularly to the fin group 51 in multiple stages. Further, the fins 51a are cut and raised in various ways at predetermined positions X in order to improve the heat transfer effect between the fins 51a and a gaseous heat exchange fluid such as air.

For example, in FIG. 7, a plurality of parallel cuts are made on the substrate 52 of the fin 51a in a direction perpendicular to the main flow direction E of air, and a cut end 53a on the upstream side and a cut end on the downstream side with respect to the main flow direction E are made. A so-called looper fin is shown in which the looper 55 is cut and raised so that the end 53b is located between the adjacent opposite fins 51a and 51a''.

In addition, in FIGS. 8(a), Φ), and (c), a plurality of parallel incisions are made on the substrate 52 of the fin 51a in a direction perpendicular to the mainstream direction E of air, and The cut end 54a on the upstream side and the cut end 54a on the downstream side indicate a so-called slit fin in which a slit 56 is cut and raised in the direction of the adjacent fin 51a' on one side.

Problems to be Solved by the Invention When the cross-fin tube heat exchanger 5o is used as an evaporator during heating in a well-known heat pump type air conditioner (not shown), the looper 55 and the slit 5
6, the heat transfer performance of the cross-fin tube heat exchanger 50 is improved, so the heat exchange performance is improved when the outside temperature is not low, compared to the case without the slit 56 or the looper 55. .

However, if the outside temperature is low, frost may form on the fins 51.
As time passes, frost grows, and frost is formed between the upstream cut end 53a and the downstream cut end 53b of the looper 55 of the adjacent fins 51a and 51a' with respect to the main flow direction E of the wind Fa. Since the distance is smaller than the fin pitch δ, it spans the width Ga of the looper 55 and closes in a short time, resulting in a sudden increase in ventilation resistance and a decrease in the heat exchange performance of the cross-fin tube heat exchanger 50. It becomes extremely bad, and sufficient heating operation becomes impossible.

The same applies to the case of the slit 56, where the upstream cut end 54a of the slit 56 and the substrate 52 of the fin 51a are connected to each other.
The space Fb, Fb' between the width Gb of the slit 56
It had the disadvantage that it was closed for many years due to frost, making heating operation impossible.

The present invention solves the conventional drawbacks described above, and when used with an evaporator during heating operation of a heat pump air conditioner,
Improves the heat exchange performance of cross-fin tube heat exchangers at normal and low outside temperatures by creating cut-and-raised fins with a shape that prevents the space in the fins from being closed by frost even when outside temperatures are low. The purpose is to

Means for Solving the Problems The present invention provides a first fin group having a first cut-up group.
fins and a second fin having a second cut-and-raised group, the first cut-and-raised group of the first fins is arranged on the first main surface in the direction of the stage of the heat exchanger. A second cut-and-raised group of the second fins is arranged on the main surface of the second fin in the step direction of the heat exchanger. The first cut-and-raised piece and the second flat piece are arranged in a stacked state in which the first fin and the second fin are stacked alternately. When viewed from the direction perpendicular to the main surface of the fin, the rear edge of the first cut-and-raised piece of the first fin overlaps with the second fin in the row direction. The front edge and the rear edge of the second cut-and-raised piece of the fin are arranged so as to be shifted from each other, and the cut-and-raised surfaces of the first and second cut-and-raised pieces are formed to be approximately parallel to the mainstream of the airflow. It is.

Function: This configuration makes it possible to partially expand the distance between the fin surfaces depending on the shape and relative position of the cut-and-raised pieces, and prevents the fins from being completely closed due to frost, thereby reducing heat at low temperatures. This dramatically improves replacement performance.

EXAMPLE Hereinafter, the present invention will be explained with reference to FIGS. 1 to 4 showing one example thereof.

1 to 4, a cross-fin tube heat exchanger 1 is composed of a fin group 2 and a heat transfer tube 3, and the fin group 2 consists of two types of alternating first fins 2a and second fins 2b. Each fin 2a, 2b consists of a laminated layer of
Fin collars 48 and 4b barred at predetermined intervals
The heat exchanger tubes 3 are inserted into these fin collars 4a14b. Further, on the main surface of the first fin 2a, there is a first groove cut and raised on one side from the first notch 5a in the step direction of the cross-fin tube heat exchanger 1.
A first cut-and-raise group 8a consisting of an alternating arrangement of cut-and-raise pieces 6a and first flat pieces 7a is arranged between the heat transfer tubes 3, and a cut-and-raise group 9 of the first cut-and-raise pieces 6a is arranged between the heat transfer tubes 3.
a maintains a positional relationship parallel to the mainstream direction of the airflow shown by arrow 2. Similarly, on the main surface of the second fin 2b, in the step direction of the cross-fin tube type heat exchanger,
A second cut-and-raised piece 6b cut and raised from the second notch 5b in the same direction as the first cut-and-raised piece 6a;
A second cut-and-raised group 8b consisting of an alternate arrangement of flat pieces 7b is arranged between the heat exchanger tubes 3, and the cut-and-raised surface 9b of the second cut-and-raised piece 6b is aligned in the mainstream direction Z of the airflow.
It is formed parallel to the

Furthermore, when the first fins 2a and the second fins 2b are viewed from the longitudinal direction of the heat exchanger tube 3 in their laminated state, as shown in the Y section, the first cut and raised pieces 6a and the second
cut and raised pieces 6b, the first flat piece 7a and the second flat piece 7a.
The flat pieces 7b overlap in the step direction of the cross-fin tube heat exchanger 1, and the cut and raised groups 8a and 8b are arranged so as to be offset in the row direction.

With the above configuration, the cut and raised pieces 6a and 6b come into contact with the airflow, and the leading edge 10a of the cut and raised pieces 6a and 6b,
The temperature boundary layer starts anew from 10b, and the fin 2a
, 2b are cut and raised pieces 6a, 6b.
Since the air flow is also disturbed at the same time as the fins are destroyed, the heat transfer coefficient of the fins 2a and 2b to the air increases, and the heat transfer performance greatly increases. Moreover, the cut and raised pieces 6a, 6
The distance S between the fins at the location b is determined by the lamination of the fins 2 at the location where the cut and raised pieces 6a and 6b overlap in the row/direction of the heat exchanger 1, for example, at the location shown in cross section J-J. The distance E between the fins in the step direction of the heat exchanger 1 is approximately twice the fin pitch S. Moreover, the cut and raised pieces 6a, 6
Even in locations where b does not overlap in the column direction of the heat exchanger 1, for example, locations indicated by - in the cross section, the inter-fin distance δ is approximately twice the fin pitch S.

Therefore, when the cross-fin tube heat exchanger of the present invention is used as an evaporator in a well-known heat pump cycle (not shown) and is used at a low outside temperature, the first flat piece 7a and the second flat piece 7a At the position 11 narrowed by the flat piece 7b, the distance between the fins is the same as the fin pitch S, so the space between the fins 2a and 2b is likely to be closed by frost, but the distance in other parts is about twice the fin pitch S. This distance makes it difficult for the heat pump to open or close due to frost, allowing the heat pump to operate for long periods of time, and overall evaporation performance at low outside temperatures is greatly improved. Moreover, the above-mentioned cut and raised pieces 6a, 6
Since the cut and raised portions 9a and 9b of b are substantially parallel to the mainstream direction Z of the airflow, there is also the advantage that the ventilation resistance does not become so large.

Effects of the Invention The cross-fin tube heat exchanger according to the present invention has fin groups arranged in an alternating manner of first fins having a first cut-and-raised group and second fins having a second cut-and-raised group. The first cut-and-raised group of the first fin is composed of first cut-and-raised pieces and first flat pieces arranged on the main surface of the first fin in the step direction of the heat exchanger. Further, the second cut-and-raised group of the second fin is composed of second cut-and-raised pieces and second flat pieces arranged on the main surface of the second fin in the step direction of the heat exchanger, Furthermore, in the stacked state of the first fin and the second fin, the first cut-and-raised piece and the second cut-and-raised piece are aligned with respect to the stage direction of the heat exchanger when viewed from a direction perpendicular to the main surface of the fin. are arranged so that they overlap and are offset from the row direction, and the first and second cut and raised surfaces are approximately parallel to the mainstream of the airflow, so that the cut and raised pieces are in contact with the airflow. A new temperature boundary layer starts from the leading edge of this cut and raised piece, and the temperature boundary layer on the main surfaces of the first fin and the second fin is destroyed by the cut and raised piece, and at the same time the air flow Because the heat transfer rate of the fins to the air increases, and the heat transfer performance increases greatly, the distance between the fins at the cut and raised pieces is about twice the fin pitch, so the distance between the fins at the place of the flat piece increases. Even if the distance between the fins is the same as the fin pitch, if this heat exchanger is used as an evaporator in a well-known heat pump cycle and operated at low outside temperatures,
The fins at the location of the cut and raised pieces are less likely to open and close due to frost, making it possible to operate the heat pump for a long time, and overall the evaporation performance in low outside temperature conditions is greatly improved. Since it is substantially parallel to the direction, it has various advantages such as the ventilation resistance is not so large.

[Brief explanation of the drawing]

Figure 1 is a main plan view of a cross-fin tube heat exchanger according to an embodiment of the present invention, and Figure 2 is a knee I# of Figure 1.
FIG. 3 is a cross-sectional view of FIG. 4(a) and (b) are partial plan views of the first and second fins before cutting and raising, and FIG. 5 is a conventional cross-fin tube heat exchanger. Figure 6 is a cross-sectional view of the heat exchanger, Figure 7 (,) is a detailed view of section X in Figure 6, Figure 7 (b) is A in Figure 7 (-).
- Cross-sectional view taken along line A, Figure 7 (C) is B of Figure 7 (-)
- A cross-sectional view taken along line B, Figure 8 (&) is a detailed view showing another conventional example of the X part in Figure 6, and Figure 8 (b) is a cross-sectional view taken along line C-C in Figure 8 (,). FIG. 8(c) is a sectional view taken along line D--D in FIG. 8(a). 1...Cross fin tube type heat exchanger, 2...
...Fin group, 2a ...First fin, 2b
...Second fin, 3...Heat transfer tube, 6a...
First cut-and-raised piece, 6b... Second cut-and-raised piece, 7a... First flat piece, 7b... Second flat piece, 8a... ...First cut-up group, 8
b...Second cut-up group, 9a...First
9b...Second cut and raise surface. Name of agent: Patent attorney Toshio Nakao and 1 other person 2 -・Calculation//1 ff/ Fig. 4 2Q...#l Phono 26...Answer 2 with fin Fig. 5 Fig. 7

Claims (1)

[Claims] A cross-fin tube heat exchanger consists of a group of fins in which multiple fins are arranged in parallel at predetermined intervals, through which airflow flows, and a group of heat transfer tubes inserted at right angles to the fins, through which refrigerant flows. and the fin group is constituted by an alternating arrangement of first fins having a first cut-and-raised group and second fins having a second cut-and-raised group, and the first fin of the first fin The cut-and-raised group is composed of first cut-and-raised pieces and first flat pieces arranged on the main surface of the first fin in the step direction of the heat exchanger, and further includes a second cut-and-raised piece of the second fin. The cut-and-raise group is composed of a second cut-and-raise piece and a second flat piece arranged on the main surface of the second fin in the direction of the heat exchanger stage, and further includes a first fin and a second flat piece. In the stacked state of the fins, the first cut-and-raised pieces and the second cut-and-raised pieces overlap in the step direction of the heat exchanger when viewed from the direction perpendicular to the main surface of the fin, and alternate in the column direction. A cross-fin tube heat exchanger arranged so that the cut and raised surfaces of the first and second cut and raised pieces are substantially parallel to the mainstream of airflow.