JPH06323691A - Evaporator - Google Patents

Abstract

PURPOSE:To provide an evaporator whose heat exchanging performance has been enhanced by a simple improvement and the cost has been reduced. CONSTITUTION:A pair of header pipes 10 are arranged vertically, a number of heat exchanging pipes 12 communicating with the two header pipes 10 are arranged at a presceribed interval, and a fin 14 is interposed between the heat exchanger pipes 12. A refrigerant supply pipe 16 to supply refrigerant into the header pipes 10 and a refrigerant discharge pipe 20 are connected on the same side with respect to the header pipes 10, an expansion valve 18 is provided on a supply side of the refrigerant supply pipe 16, and a throttle part 24 is formed in a refrigerant supply part 22 in the refrigerant supply pipe 16. By this constitution as refrigerant is expanded by the expansion valve 18 before being supplied into the header pipes 10, its velocity is increased, and therefore, the refrigerant can flow up to the depth of the header pipes 10. Thus, it is possible to make the refrigerant flow uniformly throughout the heat exchanging pipes 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporator, and more particularly to improvement of an evaporator used in an air conditioner for automobiles or households.

[0002]

2. Description of the Related Art Generally, as an evaporator used in an air conditioner for automobiles or households, for example, as shown in FIG.
0, 10, a large number of flat heat exchange tubes 12, 12 ... Connected between the header pipes 10, 10, and fins 14 for heat exchange arranged between the heat exchange tubes 12, 12. It is known to be composed.

In the evaporator thus constructed, for example, the lower header pipe 10 is connected with a refrigerant supply pipe 16 which is connected to a refrigerant supply means (not shown), and is provided in the refrigerant supply pipe 16. The refrigerant expanded by the expansion valve 18 is supplied into the lower header pipe 10.
Then, the refrigerant supplied into the lower header pipe 10 is heat-exchanged through the wall of the heat exchange pipe 12 when passing through the heat exchange pipe 12, and flows into the upper header pipe 10;
Refrigerant discharge pipe 20 connected to the upper header pipe 10
Emitted from.

However, in the evaporator constructed as described above, all the heat exchange tubes 12, 12 due to the reason that the speed of the refrigerant flowing in the header pipe is slow, or the separation of gas and liquid due to the influence of gravity occurs. It was difficult to allow the refrigerant to flow evenly through 12 ... That is, the refrigerant sent into the header pipe 10 passes through the heat exchange pipe 12 closest to the supply port side as shown in the figure without flowing to the back of the header pipe 10, and makes a short circuit to the upper header pipe 10. Since it tries to flow, the temperature of the heat exchange pipe far from the supply port side (behind the header pipe) becomes high, and there is a problem that the heat exchange efficiency is poor.

Therefore, as shown in FIG. 24, partition plates 50 are mounted in the upper and lower header pipes 10, 10 so that the refrigerant supplied from the refrigerant supply pipe 16 is in the upper and lower header pipes 1.
An evaporator in which heat exchange efficiency is improved by reciprocating between 0 and 10 has been proposed.

[0006]

However, in the evaporator proposed above, although the heat exchange efficiency is slightly better than that of the conventional one, since the refrigerant reciprocates between the upper and lower header pipes, the passage resistance of the refrigerant is reduced. In addition to the increase in the number of parts, it is necessary to install a partition plate in the header pipe, so that the manufacturing process is complicated and the cost is increased.

The present invention has been made in view of the above circumstances, and can greatly improve the heat exchange performance with a simple structure.
The purpose is to provide an evaporator that is inexpensive.

[0008]

In order to achieve the above object, a first evaporator of the present invention is provided with a pair of header pipes facing each other and a plurality of header pipes provided at a predetermined interval. A heat exchange pipe communicating between both header pipes, a fin interposed between the heat exchange pipes, a refrigerant supply pipe for supplying a refrigerant into the header pipe, and on the same side as the refrigerant supply pipe. A refrigerant discharge pipe located,
In the evaporator provided with the refrigerant expansion means provided on the supply side of the refrigerant supply pipe, a throttle portion is formed in the refrigerant supply portion of the header pipe or the refrigerant supply pipe.

In the present invention, the throttle portion may have any structure as long as it is formed in the refrigerant supply portion of the header pipe or the refrigerant supply pipe. For example, the refrigerant supply pipe may be drawn or the throttle pipe may be The throttle portion may be formed by being interposed, or the throttle portion can be formed by interposing a spacer or the like in the header pipe.

The second evaporator of the present invention includes a pair of header pipes facing each other vertically and a large number of heat exchange pipes provided at predetermined intervals between the header pipes so that the header pipes communicate with each other. A fin interposed between the heat exchange pipes, a refrigerant supply pipe arranged below to supply the refrigerant into the header pipe, and a refrigerant discharge pipe located on the same side as the refrigerant supply pipe. And a refrigerant expansion means provided on the supply side of the refrigerant supply pipe, the maximum value of the refrigerant flow velocity distribution of the refrigerant supply part in the header pipe is Fmax (cm / sec), and the refrigerant supply in the header pipe is 10 ≦ Fmax × A / V ≦ 270, where A (cm 2) is the cross-sectional area of the section and V (cm 3 / sec) is the refrigerant flow rate converted to the volume at the average pressure in the refrigerant supply section of the header pipe. It is characterized in that the flow velocity of the refrigerant in the refrigerant supply portion in the header pipe is increased so as to satisfy the above equation.

[0011]

According to the evaporator of the present invention configured as described above, the flow velocity of the refrigerant expanded by the expansion means and supplied into the header pipe can be increased, and the refrigerant is poured into the depth of the header pipe. be able to. Therefore, it becomes possible to flow the refrigerant uniformly through all the heat exchange tubes.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings. The same parts as those of the conventional evaporator will be described with the same reference numerals as in FIGS. 22 and 23.

1 and 2 are a schematic view and a partially enlarged sectional view of an evaporator according to the present invention.

The evaporator of the present invention is provided with, for example, a pair of header pipes 10 and 10 facing each other vertically and a large number of header pipes 10 and 10 at a predetermined interval, and the header pipes 10 and 10 communicate with each other. A heat exchange tube 12 for
Fins 14 interposed between the heat exchange tubes 12, 12;
Refrigerant supply pipe 16 for supplying a refrigerant into the header pipe 10
And an expansion valve 18, which is an expansion means provided on the supply side of the refrigerant supply pipe 16.

The header pipe 10 is formed in a substantially cylindrical shape, and in the illustrated embodiment, the refrigerant supply pipe 16 is connected to the lower header pipe 10 and is the same as the refrigerant supply pipe 16 of the upper header pipe 10. The refrigerant discharge pipe 20 is connected to the side. A throttle portion 24 is formed in the refrigerant supply portion 22 of the lower header pipe 10. That is, the tip end portion of the refrigerant supply pipe 16 is drawn to form the drawn portion 24, and the drawn portion 24 is fitted into the header pipe 10.

The throttle portion 24 is not necessarily the refrigerant supply pipe 16
It is not necessary to form the front end of the refrigerant by drawing. For example, as shown in FIG. 3, a spacer 26 that is formed as a narrowed part by forming a tapered hole in the center is attached to the refrigerant supply part 22. Good. In addition, as another diaphragm unit 24,
As shown in FIG. 4, the throttle member 28 may be attached to the inner diameter of the refrigerant supply pipe 16 on the refrigerant supply portion side, or
As shown in FIG. 5, the throttle portion 24 may be formed by interposing the throttle pipe 30 in the refrigerant supply pipe 16.

As described above, the refrigerant supply pipe 16 for supplying the expanded refrigerant sent from the expansion valve 18 into the header pipe 10 is connected to the header pipe 10 and the refrigerant supply in the header pipe 10 or the refrigerant supply pipe 16 is performed. By forming the throttle portion 24 in the portion 22, the flow velocity of the refrigerant expanded by the expansion valve 18 and supplied into the header pipe 10 can be increased, and the refrigerant can be flowed into the header pipe 10 deep. Therefore, the refrigerant can be made to flow uniformly through all the heat exchange tubes 12.
In this case, when supplying the refrigerant from the refrigerant supply unit 22 into the header pipe 10, it is preferable that the refrigerant does not directly contact the end portion of the heat exchange pipe 12 inside the header pipe 10. The reason is that the evaporation of the refrigerant due to the pressure loss can be prevented.

Next, a comparative experiment between the evaporator of the present invention and the conventional evaporator will be described with reference to FIGS. 6 to 9.

◎ Experimental Example 1 (corresponding to FIG. 6, FIG. 7 is a conventional example) ★ Refrigeration cycle ・ Refrigerant: Chlorodifluoromethane (CHClF2) (hereinafter referred to as R22) is used ・ Cooling capacity: 1.6kw Air conditioner system ・ Front air temperature : 27 ℃ ★ Evaporator shape ・ Parallel flow type evaporator ・ Height 250mm × width 300mm × thickness 16mm ・ Number of heat exchange tubes: 29 ・ Header pipe inner diameter: φ17.5mm ・ Header pipe length: 300mm ★ Shape ・ Inlet pipe inner diameter: φ5 mm ・ Throttle portion inner diameter: φ1.2 mm An experiment was conducted under the above conditions, and as shown in FIG. 1, the upper header pipe side (T1) of the heat exchange pipe 12 and the middle portion (T
2) and the surface temperature at three points on the lower header pipe side (T3) were measured, the results shown in FIGS. 6 and 7 were obtained, and the flow rate of the refrigerant to the header pipe 10 was provided by providing the throttle portion 24. It was found that by increasing the temperature, the refrigerant uniformly flows through each heat exchange tube 12 as compared with the conventional example.

◎ Experimental example 2 (corresponding to FIG. 8, FIG. 9 is a conventional example) ★ Refrigeration cycle ・ Refrigerant: R22 used ・ Cooling capacity: 3.2kw Air conditioner system ・ Front air temperature: 27 ° C ★ Evaporator shape ・ Parallel flow -Type evaporator ・ Height 250mm × width 420mm × thickness 21mm ・ Number of heat exchange tubes: 41 ・ Header pipe inner diameter: φ22.2mm ・ Header pipe length: 420mm ★ Shape of throttle part ・ Inlet piping inner diameter: φ6.4mm ・Inner diameter of the throttle portion: φ1.2 mm An experiment was conducted under the above conditions, and the surface temperatures at the points T1, T2 and T3 of the heat exchange tube 12 were measured in the same manner as in Experimental Example 1 above. The results as shown are obtained, and it was found that the refrigerant flows more uniformly through each heat exchange tube 12 as compared with the conventional example by providing the throttle portion 24 and increasing the flow velocity of the refrigerant into the header pipe 10.

FIG. 10 is a schematic view showing a modified example of the evaporator of the present invention, and FIG. 11 is an enlarged view thereof. In this embodiment, a capillary tube 18a is used instead of the expansion valve 18. That is, this is a case where the capillary tube 18a having a small diameter and a spiral shape is connected to the refrigerant supply pipe 16 so that the supplied refrigerant is expanded when passing through the inside of the capillary tube 18a. 10 and 11, the other parts are the same as those in the above embodiment, and the same parts are designated by the same reference numerals and the description thereof is omitted.

By the way, in the evaporator constructed as described above, the heat exchange efficiency of the refrigerant flowing through the header pipe 10 and the heat exchange pipe 12 is determined by the refrigerant flow velocity of the refrigerant supply unit 22, the cross-sectional area of the refrigerant supply unit 22, and the refrigerant. It is largely controlled by the value of the flow rate of the refrigerant in the supply unit 22. Therefore, in the present invention, the refrigerant supply unit 22 in the header pipe 10 is
Is the maximum value of the refrigerant flow velocity distribution of Fmax (cm / sec), and the sectional area of the refrigerant supply portion 22 in the header pipe 10 is A
(Cm2), refrigerant supply part 22 in header pipe 10
The refrigerant flow rate converted to volume at the average pressure inside is V (cm
3 / sec), the heat exchange performance can be improved by increasing the refrigerant flow velocity of the refrigerant supply part 22 in the header pipe 10 so as to satisfy the expression 10 ≦ Fmax × A / V ≦ 270. .

In this case, as shown in FIG. 12, the speed of the refrigerant immediately after expansion is increased by bringing the distance L between the expansion means (expansion valve 18 or capillary tube 18a) and the refrigerant supply portion 22 of the header pipe 10 close. Since it can be maintained without decelerating, it is not always necessary to provide the throttle portion 24. In this case, the distance L between the header pipe 10 and the refrigerant supply portion 22 is 0 (mm) ≦ L (mm) ≦ 90.
(Mm) It is preferable that the connecting pipe has no bent portion.

Next, an experiment for setting the above conditions will be described with reference to Tables 1 and 2 and FIGS. 12 to 21.

◎ Experimental Example 3 ★ Refrigeration cycle ・ Refrigerant: R22 used ・ Cooling capacity: 1.5kw Air conditioner system ・ Front air temperature: 27 ° C ★ Evaporator shape ・ Parallel flow type evaporator ・ Height 250mm × width 300mm × thickness 16mm ・ Number of heat exchange tubes: 29 ・ Header pipe inner diameter: φ15.1mm ・ Header pipe length: 300mm ★ Drawer shape ・ Inlet piping inner diameter: φ5mm ・ Throttle section inner diameter: φ0.7mm, φ0.9mm, φ1.
5mm, Φ4.5mm, Φ5.0mm (without diaphragm) Experiments were conducted under the above conditions and the conditions shown in Table 1, and Fig. 1
When the surface temperatures at points T1, T2 and T3 of the heat exchange tube 12 shown in FIG. 0 were measured, the results shown in FIGS. 13 to 17 were obtained, and the K value (Fmax × A / V) was 10 or more and 270 or less, It has been found that the refrigerant uniformly flows through each heat exchange tube 12 when the number is preferably 30 or more and 160 or less.

[0026]

[Table 1]

◎ Experimental Example 4 ★ Refrigeration cycle ・ Refrigerant: R22 used ・ Cooling capacity: 3.2kw Air conditioner system ・ Front air temperature: 27 ° C ★ Evaporator shape ・ Parallel flow type evaporator ・ Height 250mm × width 420mm × thickness 21mm ・ Number of heat exchange tubes: 41 ・ Header pipe inner diameter: φ19.0mm ・ Header pipe length: 420mm ★ Drawer shape ・ Inlet piping inner diameter: φ6.4mm ・ Throttle section inner diameter: φ1.0mm, φ1.2mm, φ2.
0 mm, φ6.0 mm, φ6.4 mm (no diaphragm) Experiments were conducted under the above conditions and the conditions shown in Table 2, and the results shown in FIG.
When the surface temperatures at points T1, T2 and T3 of the heat exchange tube 12 shown in FIG. 0 were measured, the results shown in FIGS. 18 to 22 were obtained, and the K value (Fmax × A / V) was 10 or more and 270 or less, It has been found that the refrigerant uniformly flows through each heat exchange tube 12 when the number is preferably 30 or more and 160 or less.

[0028]

[Table 2]

In the first embodiment shown in FIGS. 1 to 5, the case where the refrigerant supply pipe 16 is connected to the lower header pipe 10 and the refrigerant discharge pipe 20 is connected to the upper header pipe 10 has been described. The structure does not necessarily have to be such a structure, and the positions of the refrigerant supply pipe 16 and the refrigerant discharge pipe 20 may be reversed. That is, the upper header pipe 1
0 to connect the refrigerant supply pipe 16 to the lower header pipe 10
The refrigerant discharge pipe 20 may be connected to. Further, the connection position between the refrigerant supply pipe 16 and the refrigerant discharge pipe 20 may be on either the left or right side in FIG.

[0030]

As described above, since the evaporator of the present invention is configured as described above, the flow velocity of the refrigerant expanded by the expansion means and supplied into the header pipe is increased. Therefore, the refrigerant can be poured into the depth of the header pipe, and the refrigerant can be uniformly flowed to all the heat exchange tubes. Therefore, the heat exchange performance can be greatly improved by a simple improvement without increasing the passage resistance of the refrigerant, and an inexpensive evaporator can be provided.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an evaporator of the present invention.

FIG. 2 is an enlarged sectional view of a portion of the evaporator shown in FIG.

FIG. 3 is an enlarged cross-sectional view showing a modified example of the refrigerant supply unit of the header pipe according to the present invention.

FIG. 4 is an enlarged cross-sectional view showing a throttle portion provided in the refrigerant supply pipe in the present invention.

FIG. 5 is an enlarged cross-sectional view showing another throttle portion provided in the refrigerant supply pipe according to the present invention.

FIG. 6 is a graph showing Experimental Example 1 of the evaporator of the present invention.

FIG. 7 is a graph showing a conventional example of Experimental Example 1 of the evaporator of the present invention.

FIG. 8 is a graph showing Experimental Example 2 of the evaporator of the present invention.

FIG. 9 is a graph showing a conventional example of Experimental Example 2 of the evaporator of the present invention.

FIG. 10 is a schematic view showing a modified example of the evaporator of the present invention.

11 is an enlarged cross-sectional view of FIG.

FIG. 12 is an enlarged cross-sectional view showing another modified example of the evaporator of the present invention.

FIG. 13 is a graph showing Experimental Example 3 of the evaporator of the present invention.

FIG. 14 is a graph showing Experimental Example 3 of the evaporator according to the present invention.

FIG. 15 is a graph showing Experimental Example 3 of the evaporator according to the present invention.

FIG. 16 is a graph showing Experimental Example 3 of the evaporator of the present invention.

FIG. 17 is a graph showing Experimental Example 3 of the evaporator according to the present invention.

FIG. 18 is a graph showing Experimental Example 4 of the evaporator according to the present invention.

FIG. 19 is a graph showing Experimental Example 4 of the evaporator according to the present invention.

FIG. 20 is a graph showing Experimental Example 4 of the evaporator according to the present invention.

FIG. 21 is a graph showing Experimental Example 4 of the evaporator according to the present invention.

FIG. 22 is a graph showing Experimental Example 4 of the evaporator according to the present invention.

FIG. 23 is a partial cross-sectional view showing the structure of a conventional evaporator.

FIG. 24 is a partial cross-sectional view showing the configuration of another conventional evaporator.

[Explanation of symbols]

 10 Header Pipe 12 Heat Exchange Pipe 14 Fin 16 Refrigerant Supply Pipe 18 Expansion Valve (Refrigerant Expansion Means) 18a Capillary Tube (Refrigerant Expansion Means) 20 Refrigerant Discharge Pipe 22 Refrigerant Supply Port 24 Throttling Portion 26 Spacer 28 Throttling Member 30 Throttling Pipe

Claims (2)

[Claims] 1. A pair of header pipes facing each other vertically, a large number of heat exchange pipes provided at predetermined intervals between the header pipes and communicating between the header pipes, and a heat exchange pipe between the heat exchange pipes. Mounted fins, a refrigerant supply pipe for supplying a refrigerant into the header pipe, a refrigerant discharge pipe located on the same side as the refrigerant supply pipe, and a refrigerant expansion means provided on the supply side of the refrigerant supply pipe. In the evaporator provided, an evaporator is characterized in that a throttle portion is formed in a refrigerant supply portion of the header pipe or the refrigerant supply pipe. 2. A pair of header pipes facing each other vertically, a plurality of heat exchange pipes provided at predetermined intervals between the header pipes and communicating between the header pipes, and a heat exchange pipe interposed between the heat exchange pipes. Mounted fins, a refrigerant supply pipe arranged below to supply the refrigerant into the header pipe, a refrigerant discharge pipe located on the same side as the refrigerant supply pipe, and a supply side of the refrigerant supply pipe. In the evaporator provided with the refrigerant expansion means provided, the maximum value of the refrigerant flow velocity distribution of the refrigerant supply part in the header pipe is Fmax (cm / sec), the cross-sectional area of the refrigerant supply part in the header pipe is A (cm2), When the refrigerant flow rate converted to the volume at the average pressure in the refrigerant supply section of the header pipe is V (cm3 / sec), the above header is satisfied so as to satisfy the formula 10≤Fmax × A / V≤270. Evaporator, characterized in that to increase the refrigerant flow rate of the coolant supply unit in the pipe.