JPH10267462A - Evaporator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporator which enables improvement of the coefficient of performance of a refrigerating cycle without making up a complicated system. SOLUTION: An evaporator 1 has forward and rear header parts which are disposed mutually at intervals and a number of flat tube parts whose forward and rear ends are connected respectively to the forward and rear header parts. By providing the forward and rear header parts with partitions 12, 13 respectively a refrigerant passageway 21 partitioned zigzag into a plurality of passageways 21A, 21B, 21C is formed. Through the header part partition 12 a nozzle part 20 which expands refrigerant and diverts its flow in a manner of a distributor to a downstream passageway 21C is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an evaporator used for a car air conditioner and the like.

[0002]

2. Description of the Related Art Conventionally, an evaporator used for a car air conditioner or the like includes a front and rear header section which are arranged at an interval from each other and a large number of flat tube sections whose front and rear ends are respectively connected to the front and rear header sections. By providing at least one partition in each of the front and rear header portions, a meandering refrigerant passage divided into a plurality of passages each having a plurality of flat tube portions is formed, and a refrigerant introduction port is provided at one end of the front header portion. In addition, there is a known configuration in which a refrigerant outlet is provided at the other end of the rear header portion. In addition, since the refrigerant introduction pipe and the refrigerant discharge pipe are arranged on the same side of the heat exchanger, the refrigerant introduction pipe is inserted from the other end of the front header portion to near one end in the header portion, and the rear header portion is There is also known one provided with a refrigerant outlet at the other end.

[0003]

In car air conditioners and the like, it is of utmost importance to improve the air conditioner performance, that is, to improve the efficiency (coefficient of performance) of the refrigeration cycle of the system. As shown in FIG. 10, a refrigerant such as a car air conditioner repeats a refrigeration cycle of compression, condensation, expansion and evaporation. Then, in the evaporator, the liquid-rich refrigerant enthalpy i _0, enthalpy and evaporated while passing through the respective passages i _1, and the sent to the compressor. It is known that the amount of increase in enthalpy (i ₁ −i ₀ ) in the evaporator contributes to the improvement of the coefficient of performance. As one means for improving the coefficient of performance,
There has been proposed a system in which a refrigerant expanded once is cooled by an expansion valve installed in front of an evaporator, turned into a saturated liquid, and then further expanded to re-expand the refrigerant.

[0004] However, the addition of an expansion valve upstream of the evaporator has a problem that the expansion valve is expensive and the system becomes complicated, making it difficult to handle.

An object of the present invention is to provide an evaporator that can improve the coefficient of performance of a refrigeration cycle without configuring a complicated system.

[0006]

The evaporator according to the first aspect of the present invention comprises a front and rear header portion spaced apart from each other and a plurality of flat tube portions each having front and rear ends connected to the front and rear header portion, respectively. By providing at least one partition in each of the front and rear header portions, at least one header portion partition is provided in an evaporator in which a meandering refrigerant passage partitioned into a plurality of passages each having a plurality of flat tube portions is formed. And a nozzle section for expanding the refrigerant and dividing the refrigerant into a downstream passage.

An evaporator according to a second aspect of the present invention includes a front and rear header portion and a plurality of flat tube portions whose front and rear ends are respectively connected to the front and rear header portions. By being provided at least one each, a meandering refrigerant passage partitioned into a plurality of passages each having a plurality of flat tube portions is formed, and one end side of one of the front and rear header portions is provided in the header portion. In the evaporator in which the inner pipe is inserted to the vicinity of the other end, the inner pipe is provided with a nozzle portion for expanding the refrigerant and dividing the refrigerant into a downstream passage.

According to the first and second aspects of the evaporator, a part of the refrigerant expands through the nozzle portion and is diverted, and does not pass through a part of the meandering refrigerant passage, but flows therethrough. It leads to the flow passage. As a result, two types of refrigerants having different degrees of dryness are mixed, and a refrigerant in a new state is produced. The enthalpy of the refrigerant in the new state is smaller than the enthalpy of the high-dryness refrigerant that has reached the downstream passage without passing through the nozzle portion, and eventually becomes a gas having the same enthalpy as the conventional one. It is discharged from the evaporator.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In this specification, the front, rear, left and right are based on FIG. 4, and the upper and lower sides of the figure are referred to as front and rear, respectively, and the left and right sides of the figure are referred to as left and right.

FIGS. 1 to 5 show an evaporator according to the present invention.
1 shows a first embodiment of (1).

As shown in FIG. 1, the evaporator (1) is made of aluminum (including an aluminum alloy), and has a U-shaped recess for forming a refrigerant flow passage formed on one surface of a substantially rectangular intermediate plate (2). (3) and two header forming recesses (4) connected to the front and rear upper end portions thereof are provided, and every other intermediate plate (2) adjacent to each other forms a recess (3) (4). The two intermediate plates (2) are joined to each other by being superposed in layers while facing each other, so that the front and rear portions of the U-shaped flat tube portion (5) and both ends of each flat tube portion (5) are connected. A pair of header parts (6)
(7) is formed. Adjacent flat tube parts (5)
The intermediate plates (2) opposing each other are joined such that the bottom walls (4a) of these header forming recesses (4) are butted against each other, and between the flat tube portions (5). Corrugated fins (8) are interposed.

Side plates (9) are arranged on both left and right outer sides of the evaporator (1), respectively.
A corrugated fin (8) is also interposed between the flat tube section (5). Both side plates (9) and the intermediate plate (2) are each made of aluminum brazing sheet. A refrigerant inlet (22) is provided at the right end of the front header (6), a refrigerant inlet pipe (10) is welded to the periphery thereof, and a refrigerant outlet (23) is provided at the left end of the rear header (7). A refrigerant discharge pipe (11) is welded to the periphery. In the evaporator (1), air flows from the rear to the front, and the air and the refrigerant passing through the gap where the corrugated fins (8) are present pass through the wall of the plate (2) and the corrugated fins (8). Heat exchange through.

FIG. 3 shows an intermediate plate (2A) used as a partition for the rear header and a standard intermediate plate.
(2). As shown in the figure, each plate (2
At the center of the width of the recess (3) for forming the refrigerant flow channel of (A) and (2), a partitioning ridge (15) which is vertically long and has the same height as the peripheral edge of the plate (2A) (2). Are provided from the upper end to the lower end of the recess (3). A plurality of ridges (16) having a height twice the depth of the recess (3) are provided in the recess (3) for forming the coolant channel of each plate (2A) (2). Each convex stripe (16)
Has a shape that is exactly half of the U-shape, and in a state where both plates (2) and (2) are superimposed, the tips of the ridges (16) face the plates (2A) (2 ), A parallel U-shaped divided refrigerant flow path is formed in the U-shaped refrigerant flow path of the flat tube portion (5). Bottom wall (4a) of front and rear header forming recess (4)
In addition, a substantially oblong refrigerant passage hole (17) is formed long before and after. Further, at the lower end of the plate (2A) (2), there is provided an interval maintaining convex part (18) having the same height as the bottom wall (4a) of the front and rear header forming concave part (4), and the plate (2A) ( 2) A substantially triangular front and rear reinforcing projection (19) having the same height as the peripheral edge of the plate (2A) (2) is provided at the front and rear corners at the lower end.

As shown in FIG. 4, a front header partition (12) is provided at a position approximately one-third to the left of the right end of the front header (6), and a left end of the rear header (7) is provided. A rear header partition (13) is provided closer to the right by about one third. As shown in FIG. 3, the front header partition (12) is formed on the bottom wall of the header forming recess (4) of the intermediate plate (2).
(4a) is formed by not forming a coolant passage hole. Intermediate plate (2) serving as front header partition (12)
A nozzle portion (20) is further provided on the bottom wall (4a) of the header forming concave portion (4). This nozzle part (20) is shown in FIG.
Although it is shown enlarged, it is open to the left and its caliber is
It is sufficiently smaller and wider than the refrigerant passage hole (17). Such a nozzle portion (20) can be provided by, for example, burring. Although not shown, the rear header partition (13) is formed by not allowing a coolant passage hole to be formed in the bottom wall (4a) of the header forming recess (4) of the intermediate plate (2A). .

As shown in FIG. 2, the front header partition (1
2) and the rear header partition (13), the evaporator (1) has an inlet passage (21A), an outlet passage (21C) and both passages.
(21A) 3 consisting of an intermediate passageway (21B) located in the middle of (21C)
(21A) (21B) (21C)
(21A) and the meandering refrigerant passage in which the flow of the refrigerant in the outlet side passage (21C) is made to flow counter to the flow direction of air.
(21) is formed.

Therefore, the refrigerant introduction pipe on the right side of the evaporator (1)
(10) The refrigerant introduced into the refrigerant inlet (22) at the right end of the front header portion (6) is turned by the front header partition (12) and flows countercurrent to the air flow direction. The entrance side passage (21A) is reached, and the rear header partition (1
3) the intermediate passage (21B) turned parallel to the flow direction of the air, the outlet passage (21C) opposed to the flow direction of the air, and the rear header (7). The refrigerant is discharged from the refrigerant discharge pipe (11) through the refrigerant discharge port (23) at the rear end. Here, since the front header section partition (12) is provided with the nozzle section (20), a part of the refrigerant expands and is diverted through the nozzle section (20), and is divided into the inlet side passageway (21A). ) From the start point to the end point of the intermediate passage (21B) without passing through these passages (21A) (21B). Therefore, a part of the liquid-rich refrigerant at the starting point of the inlet-side passage (21A) expands and mixes with the air-rich refrigerant after passing through the intermediate passage (21B). That is,
The low-dryness refrigerant and the high-dryness refrigerant are mixed.
Thus, by mixing the refrigerants in the two types of states having different state quantities, a mixed refrigerant having a new state quantity is produced. The mixed refrigerant flows through the outlet side passageway (21C) and is completely evaporated before being discharged.

FIG. 6 shows a pressure-enthalpy diagram of a refrigeration cycle using the above evaporator (1).
As shown in the figure, most of the liquid-rich refrigerant having the enthalpy of i ₀ is supplied to the inlet passage (21A) and the intermediate passage (21A).
Enthalpy is i _b evaporates while passing through the B). The refrigerant enthalpy is passed through the nozzle portion (20) is substantially i _0, after reducing the pressure to expand, is mixed with the refrigerant enthalpy becomes i _b. Thus two different state quantity of state (pressure and enthalpy) refrigerant (refrigerant in the refrigerant and i _b enthalpy value i ₀₎ with, due mixture, new state (pressure and enthalpy, to both the weight ratio of (A state having a corresponding intermediate value). Assuming that the enthalpy of the mixed refrigerant is i _a , i ₀
<I _a <i _b, and the by then completely evaporated while passing through the outlet passage (21C), enthalpy _{i 1 (i b <i 1} )
And sent to the compressor.

[0019] When this is compared with the conventional refrigeration cycle shown in FIG. 10, (i _b -i _a) only and the overall enthalpy is increased, the coefficient of _{performance, (i b -i a) /} (i 1
−i ₀ ) It can be seen that it is improved.

In the first embodiment, the front and rear header portions
(6) The positions where the partitions (12) and (13) are provided in (7) are not limited to exactly one-third from each of the right and left ends, but may be appropriately shifted to the right and left in consideration of heat exchange performance. In the above embodiment, the number of paths (21A), (21B), and (21C) is three, but the partitions (12) and (13) are added to the front header section (6) and the rear header section (7). By providing them alternately, four or more passages may be formed. In this case, the position of the partition provided with the nozzle portion (20) is more effective as the difference in the state quantity is larger, and is basically provided in the partition closer to the entrance side as described above, but is not limited to this. Instead, it may be provided at any position as long as the refrigerant is expanded and diverted to the downstream passage, or may be provided at two or more positions. The shape of the nozzle part (20) is determined by the size of the evaporator (1) and operating conditions. However, the amount of refrigerant diverted from the nozzle portion (20) is specified to be 50% or less of the whole.

FIGS. 7 to 9 show a second embodiment of the present invention.

The evaporator (31) differs from that of the first embodiment in that an inner pipe (32) for introducing a refrigerant is added.

That is, as shown in FIG. 7, a refrigerant introduction pipe (33) communicating with the left end of the front header section (6) is welded to the left side plate (9).
And the refrigerant discharge pipe (11) is located on the left side of the evaporator (31). As shown in FIG. 9, the inner pipe (32) communicates with the refrigerant introduction pipe (33), and the inner pipe (32) has a refrigerant passage gap between the inner pipe (32) and the periphery of the refrigerant passage hole (8) of each plate (2). It is inserted into the header (6). The refrigerant introduction pipe (33) is welded to the edge of the refrigerant introduction pipe connection port (35) provided on the side plate (9), and the left end of the inner pipe (32) is connected to the refrigerant introduction pipe (33). The right end is brazed to the edge of the inner pipe insertion hole (36) provided in the partition (34) of the front header (6). Front header (6) partition (34)
Is the bottom wall (4) of the recess (4) for header formation on the intermediate plate (2).
The inner pipe insertion hole (36) is formed by not allowing a refrigerant passage hole to be drilled in a), and the bottom wall (4a)
It is formed by drilling a through hole smaller than the coolant passage hole (17).

In the middle of the inner pipe (32), there is provided a nozzle part (40) which is open forward. The diameter of the nozzle portion (40) is sufficiently smaller and wider than the diameter of the inner pipe (32). In addition, the nozzle part (40)
The position of the nozzle may be located anywhere on the inner pipe (32) as long as it is between the side plate (9) and the partition (34). It is not limited to.

Inner pipe (32), front header partition
(34) and the rear header partition (13), the evaporator (31)
The entrance passage at the right end (41A) and the exit passage at the left end
(41C) and three passages (41A), (41B) and (41C) consisting of an intermediate passage (41B) located between the two passages (41A) and (41C), and the entrance passage (41A) and the exit A meandering refrigerant passage (41) is formed in which the flow of the refrigerant in the side passage (41C) is opposed to the flow direction of the air.

Therefore, the refrigerant introduction pipe (33) of the evaporator (31)
And it is sent to the right end of the front header part (6) by the inner pipe (32) communicating therewith, and is turned by the right side plate (9). Then, it flows through the inlet side passageway (41A) which is a counterflow with respect to the air flow direction, and is further turned by the rear header partition (13) and is an intermediate passageway which is parallel to the airflow direction. (41
B), the outlet side passage which is a counter flow to the air flow direction
(41C) is discharged from the refrigerant discharge pipe (11) through the rear end of the rear header (7). Here, since the inner pipe (32) is provided with the nozzle portion (40), a part of the refrigerant expands and is diverted through the nozzle portion (40), so that the refrigerant flows through the inlet side passageway (41A). Intermediate passage (41B) from the starting point
Without passing through these passages (41A) and (41B). Therefore, a part of the liquid-rich refrigerant at the starting point of the inlet side passage (41A) expands and expands in the intermediate passage (4A).
1B) It mixes with the air-rich refrigerant after passing. That is, the low-dryness refrigerant and the high-dryness refrigerant are mixed. Thus, by mixing the refrigerants in the two types of states having different state quantities, a mixed refrigerant having a new state quantity is produced. The mixed refrigerant flows into the outlet side passage.
It flows through (41C) and is completely evaporated before being discharged.

The pressure-enthalpy diagram of the refrigeration cycle using the evaporator (1) of the second embodiment is similar to that shown in FIG. 6, and compared with the conventional refrigeration cycle shown in FIG.
(I _b -i _a) only has total enthalpy increases, coefficient of performance, is improved _{(i b -i a) / (} i 1 -i 0).

In the first embodiment, the front and rear header portions
(6) The position where the partitions (34) and (13) are provided in (7) is not limited to just one third from each of the left and right ends, but may be shifted to the right or left as appropriate in consideration of heat exchange performance. Further, in the above embodiment, the number of paths (41A) (41B) (41C) is three, but the partitions (34) and (13) are added to the front header section (6) and the rear header section (7). By providing them alternately, four or more passages may be formed. In this case, the position where the nozzle portion (40) is provided is more effective as the difference in the state quantity is larger, and if the position is such that the refrigerant is expanded and divided into the downstream passage,
It may be provided anywhere, or may be provided at two or more places. Further, the shape of the nozzle part (40) is determined by the size of the evaporator (31) and the use conditions. However, the nozzle (4
The amount of refrigerant diverted from 0) is specified to be 50% or less of the whole.

[0029]

According to the evaporator of the first and second aspects, a part of the refrigerant expands through the nozzle portion and is divided, and does not pass through a part of the meandering refrigerant passage. Then, the refrigerant reaches a downstream passage, whereby two types of refrigerants having different degrees of dryness are mixed to produce a refrigerant in a new state. The enthalpy of the refrigerant in the new state is smaller than the enthalpy of the high-dryness refrigerant that has reached the downstream passage without passing through the nozzle portion, and eventually becomes a gas having the same enthalpy as the conventional one. It is discharged from the evaporator. To improve the coefficient of performance of a refrigeration cycle including an evaporator,
The sum of the enthalpy increase until the refrigerant introduced into the evaporator is mixed and the enthalpy increase until the discharge of the refrigerant after mixing contributes, and the sum increases, thereby improving the coefficient of performance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of an evaporator according to the present invention.

FIG. 2 is a perspective view showing a refrigerant flow path of the evaporator.

FIG. 3 is a perspective view showing an intermediate plate constituting the evaporator.

FIG. 4 is a horizontal sectional view of a header portion of the evaporator.

FIG. 5 is an enlarged view of a nozzle section.

FIG. 6 is a pressure-enthalpy diagram of a refrigeration cycle employing an evaporator according to the present invention.

FIG. 7 is a perspective view showing a second embodiment of the evaporator according to the present invention.

FIG. 8 is a perspective view showing a refrigerant flow path of the evaporator.

FIG. 9 is a horizontal sectional view of a header portion of the evaporator.

FIG. 10 is a pressure-enthalpy diagram of a refrigeration cycle employing a conventional evaporator.

[Explanation of symbols]

 (1) (31) Evaporator (5) U-shaped flat tube (6) (7) Front and rear headers (12) (13) (34) Partition (21) (41) Meandering refrigerant passage (20) ( 40) Nozzle part (21A) (21B) (21C) Partition passage (pass) (32) Inner pipe (41A) (41B) (41C) Partition passage (pass)

Claims (2)

[Claims] 1. Front and rear header portions (6) and (7) and front and rear header portions (6) which are arranged at an interval from each other.
(7) is provided with a number of flat tubes (5), and at least one partition (12) (13) is provided in each of the front and rear headers (6) (7), so that a plurality of flat tubes are provided. In the evaporator in which the meandering refrigerant passage (21) partitioned into a plurality of passages (21A), (21B), and (21C) including the portion (5) is formed, at least one header partition (12) includes: An evaporator comprising a nozzle section (20) for expanding a refrigerant and dividing the refrigerant into a downstream path (21C). 2. Front and rear header portions (6) and (7) and front and rear header portions (6) which are arranged at an interval from each other.
(7), a plurality of flat tubes (5) are provided, and at least one partition (34) (13) is provided in each of the front and rear headers (6) (7). A meandering refrigerant passage (41) partitioned into a plurality of passages (41A), (41B), and (41C) having a section (5) is formed, and one of the front and rear header sections (6) and (7) is formed. In the evaporator in which the inner pipe (32) is inserted from one end side to near the other end in the header portion,
In the inner pipe (32), the refrigerant is expanded and the downstream path (4
1C) is provided with a nozzle part (40) for diverting the water.