JPH0320576A - Evaporator - Google Patents

Abstract

PURPOSE:To improve the cooling performance of an evaporator, suppress the pressure loss, and clear waterdrops with a good efficiency by forming on level parts of corrugated fins louvers extended breadthways and arranged in parallel at a specific ratio of the height of the louvers to the pitch of the level parts of the corrugated fins. CONSTITUTION:On corrugated fins, since condensed water flows down through a slit 24 from an upper level part 21 onto a lower level part 21, the smaller a pitch P is, the more easily condensed water flows down. Accordingly, given a constant value H as the height of louvers 23, the pitch P becomes smaller the smaller the gap G between louvers 23 is, hence the more easily the condensed water falls. In considering the efficiency of an evaporator, the pressure loss as well as the cooling performance is an important factor. In considering the effect of such factors together with the effect on the fall of condensed water, all such factors can be made satisfactory by setting the gap ratio H/P in the range of 0.75-0.90.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an evaporator used in car air conditioners and the like.

In conventional technology evaporators, when air is cooled, moisture in the air condenses, and the condensed moisture forms water droplets that adhere to the fins. Water droplets adhering to the fins fall due to their own weight and are drained, but as a means to improve drainage, the surfaces of the fins have sometimes been chemically treated to make them hydrophilic.

Incidentally, the fins are shaped with louvers, and the shape of the louvers was determined with the main objectives of improving the cooling performance of the evaporator and suppressing the increase in pressure loss, and the shape of the louvers was determined with the main objectives of improving the cooling performance of the evaporator and suppressing the increase in pressure loss. was not considered.

Problems to be Solved by the Invention An object of the present invention is to improve the cooling performance of the evaporator, to suppress an increase in pressure loss, and to provide an evaporator with good drainage of water droplets.

Means for Solving the Problems In the evaporator according to the present invention, louvers extending in the width direction of the corrugated fins are formed in parallel on each flat part of the corrugated fins, the pitch of the flat parts of the corrugated fins is P, and the height of the louvers is When S is H, H / P - 0.7
5 to 0.90.

Example Embodiments of the invention will now be described with reference to the drawings.

As shown in Fig. 3, the evaporator consists of a serpentine flat tube l2 made of extruded aluminum and having a parallel refrigerant passage l2.
, a louvered corrugated fin L3 made of an aluminum brazing sheet interposed between adjacent straight pipe parts of the flat pipe 12, and an inlet header l4 and an outlet header provided at both ends of the flat pipe 12, respectively. 15.

The surfaces of the canal 12 and the fins 13 are treated with a hydrophilic film.

As shown in detail in FIG. 4, the corrugated fin 13 is
It consists of parallel flat portions 2l and a U-shaped bent portion 22 connecting the ends of the adjacent flat portions 2l on the same side. Louvers 23 extending over the entire length in the 111 direction are formed in parallel on each flat portion 21. A slit 24 is formed between adjacent louvers 23 by cutting and raising the louvers 23. As shown in FIG. 5, the louvers 23 formed on each flat portion 2l are divided into four groups 81.
- S4, and the orientation of every other louver 23 in each group S1 to S4 is the same.

FIG. 1 shows important factors in fin design, which are as follows.

P: Pitch of flat part of fin θ: Angle of louver d e g. W: Mountain of the louver Wheel H: Height of the louver G: Gap between the louvers (P-H) ■In the above corrugated fin, condensed water passes through the slit 24 from the upper flat part 2l to the lower flat part. Since the condensed water flows down to 2L, the smaller the pitch P, the easier the condensed water will flow down. Therefore, when the height H of the louvers 23 is constant, the smaller the gap G between the louvers 23, the smaller the pitch P, and the easier the condensed water will fall.

Preferred specific values of the above factors are as follows. That is, P-1.8 to 2.2, θ-28 to 38, W-2
．． It is preferable that it is 3-2.7. Further, the height of the louver is calculated by the formula HmW-tan(θ).

Therefore, if we define gap ratio - H/P as another factor that serves as a guideline for fin design, the larger the gap ratio, the greater the effect of condensed water falling.

Table 1 shows the specific numerical values of each of the above factors.

(Margins below) Table 1 In the above, only the effect of condensed water falling has been considered regarding the gap ratio, but cooling performance and pressure loss are also important factors for the performance of the evaporator. The graph shown in FIG. 2 summarizes these factors regarding the effect of condensed water falling and the gap ratio. The data in the graph was actually measured for an evaporator with the following specifications. That is, the width A of the evaporator is 32 Clams.
, the height B is 23Cl+++s, and the depth C is 90cm (see Figure 3). Although the above specifications may be changed as necessary, it is particularly preferable that the depth C is 65 to 110+a.

As is clear from Fig. 2, the gap ratio H/P −
It can be seen that a range of 0.75 to 0.90 satisfies all the elements.

To summarize each factor above, if the louver width W is set large, the louver angle θ should be set small, and if the louver width W is set small, the louver angle θ should be set small to reduce the pitch P. Alternatively, the pitch P may be set to be wider by increasing the louver angle θ.

FIG. 6 shows an evaporator of a different type from the evaporator described above. In other words, this evaporator is
It includes parallel flat tubes 3i and corrugated fins 32 interposed between adjacent flat tubes 31. Each plating tube 31 is formed by overlapping and joining two plating sheets 33 press-molded into a generally gutter shape to form a refrigerant passage between the two sheets 33. Flat tube 3
A bulging portion 34 is provided at the upper part of the tank l, and a header tank portion 35 is provided by joining adjacent bulging portions 34 in a communicating manner.

An inlet pipe 36 and an outlet pipe 37 are connected to the header tank section 35 . The corrugated fins 32 are the same as the fins 3 of the evaporator shown in FIG. 3 above.

Effects of the Invention According to the present invention, an evaporator is provided which not only improves the cooling performance of the evaporator and suppresses an increase in pressure loss, but also has good water droplet drainage performance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the fins of the evaporator according to the present invention, and FIG. 2 is a graph showing the performance of the evaporator. FIG. 3 is a perspective view of the entire evaporator, FIG. 4 is an enlarged front view of a portion of the fin, and FIG. 5 is a longitudinal sectional view of a portion of the fin. FIG. 6 is an overall perspective view of another evaporator. l3...Fin, 2l...Fin flat part, 23...
- Louver, P...Pitch of fin flat part, H...Height of louver. Above Chapter IvA 1 Gap rate % Figure 7J2

Claims (1)

[Claims] Louvers extending in the width direction of each flat part of the corrugated fin are formed in parallel, and when the pitch of the flat part of the corrugated fin is P and the height of the louver is H, An evaporator characterized in that H/P=0.75 to 0.90.