JP2003065631A - Freezer, and its condenser and evaporator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a heat transfer rate among a refrigerant, a cooling fluid, and a fluid to be cooled in a freezer including a shell and tube type condenser and a shell and tube type evaporator. SOLUTION: A shell and tube type condenser is adapted such that a cooling fluid is made to flow in a plurality of heat transfer tubes disposed horizontally from the lower heat transfer tube group to the upper heat transfer tube group after folded back at tube ends with a refrigerant forced to flow from an upper to lower potion to the outside of the heat transfer tubes. In the condenser, the diameter of the lower heat transfer tube group is more reduced than that of the upper heat transfer tube group. Further, a shell and tube type evaporator is adapted such that a fluid to be cooled in a plurality of heat transfer tubes disposed horizontally is forced to flow to adjacent heat transfer tube groups in succession after folded back at tube ends with a refrigerant contained outside the heat transfer tubes. In the evaporator, the diameter of a downstream heat transfer tube group is more reduced than that of an upstream heat transfer tube group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator suitable for application to a large-sized turbo refrigerator, a condenser and an evaporator thereof.

[0002]

2. Description of the Related Art FIG. 10 shows a configuration example of a turbo refrigerator. In FIG. 10, reference numeral 1 denotes a condenser, which functions to cool, condense, and liquefy the pressurized refrigerant through the heat transfer tube 10 with cooling water that enters from the inflow port 6 and flows out from the outflow port 7. The refrigerant liquefied in the condenser 1 is discharged from the outlet pipe 9 of the condenser 1 to the expansion valve 1
After being decompressed by flowing to 1, the container 4 constituting the evaporator 2
It flows in.

In the evaporator 2, the water to be cooled, which flows through the heat transfer pipe 5 from the inlet 12 and flows out from the outlet 13, exchanges heat with the refrigerant to cool the water to be cooled and vaporize the refrigerant. The vaporized refrigerant is sucked by the turbo (centrifugal) compressor 3 and compressed, and then flows from the inlet pipe 8 to the condenser 1. The water to be cooled that is cooled in the heat transfer tube 5 of the evaporator 2 and flows out from the outlet 13 in this manner is used for air conditioning of a building or the like.

Heat transfer tube 10 for flowing cooling water in the condenser 1.
Is composed of a large number of heat transfer tubes arranged horizontally, and the cooling water flowing from the inflow port 6 flows through the lower one path heat transfer tube group shown in FIG. It is configured such that it returns and flows into the heat transfer tube group in the second upper path and flows out from the outlet 7. On the other hand, the pressurized refrigerant flowing from the turbo compressor 3 through the inlet pipe 8 flows from the upper side to the lower side, and during that time, it is cooled by the cooling water flowing in the heat transfer tube 10 and condensed and liquefied. In this way, in the condenser 1, a flow path composed of a plurality of heat transfer tube groups is arranged in the vertical direction so that the cooling water flows from the lower heat transfer tube group to the upper heat transfer tube group at the tube end. Is formed by partitioning at the pipe end.

On the other hand, the heat transfer tube 5 through which the water to be cooled, which is heat-exchanged with the liquid refrigerant flowing through the expansion valve 11 into the container 4 constituting the evaporator 2, flows is composed of a large number of horizontally arranged heat transfer tube groups. When the water to be cooled which has flowed in from the inflow port 12 exits the pipe end on the opposite side, it is folded back and flows into the horizontal heat transfer tube group and flows out from the outflow port 13 so as to be arranged laterally as shown in FIG. A flow path is formed by partitioning the flow path consisting of the plurality of heat transfer tube groups a, b, c, and d formed by the tube ends. In the evaporator 2, the water to be cooled is caused to flow in the lateral direction as described above. When the water to be cooled is caused to flow in the vertical direction, the refrigerant gas generated in the lower heat transfer tubes is filled between the upper heat transfer tubes and the heat transfer coefficient is poor. Because it will be.

In the turbo refrigerator having the above-described structure, in the condenser 1, the pressurized refrigerant is in contact with the heat transfer tube 10 located above and cooled on the surface of the heat transfer tube 10 to be liquefied.
The liquefied refrigerant flows down to the heat transfer tube 10 located below.
Therefore, in the heat transfer tube 10 located below, the liquid film condensed on the upper heat transfer tube 10 flows down, so that the liquid film on the surface of the heat transfer tube becomes thicker and the condensation heat transfer coefficient at that portion is lowered.

On the other hand, in the evaporator 2 in the above-mentioned turbo refrigerator, the temperature difference between the water to be cooled flowing in the heat transfer tube 5 and the refrigerant flowing around the heat transfer tube 5 is large on the upstream side of the water to be cooled, and the heat flux is large. Although the heat transfer coefficient is large and the heat transfer rate is good, the temperature difference between the cooled water flowing in the heat transfer tube 5 group and the refrigerant flowing around the heat transfer tube 5 is small in the heat transfer tube 5 group on the downstream side, Compared with this, there is a problem that the heat flux is small and the heat transfer coefficient is low. As described above, the conventional turbo refrigerator has a problem that the cooling efficiency of the refrigerator is lowered because the heat transfer coefficient lowering portion occurs in the condenser and the evaporator.

[0008]

DISCLOSURE OF THE INVENTION According to the present invention, a cooling fluid is folded back at a tube end into a plurality of horizontally arranged heat transfer tubes to flow from a lower heat transfer tube group to an upper heat transfer tube group and the same heat transfer tube. A shell-and-tube type condenser configured to flow a refrigerant to the outside from the top to the bottom, and a cooled fluid is folded back to adjacent heat transfer tube groups in a plurality of horizontally arranged heat transfer tubes. In a turbo refrigerator having a shell-and-tube type evaporator configured to flow laterally sequentially and to store the refrigerant outside the heat transfer tube, the heat exchange heat amount between the refrigerant and the cooling fluid and the cooled fluid is changed. The challenge is to improve.

[0009]

In order to solve the above-mentioned problems, the present invention folds a cooling fluid at a tube end into a plurality of horizontally arranged heat transfer tubes so that a heat transfer tube group from a lower heat transfer tube group to an upper heat transfer tube group. A shell-and-tube type condenser configured so that the refrigerant flows from the upper side to the lower side outside the heat transfer tube, and the tube diameter of the lower heat transfer tube group is smaller than that of the upper heat transfer tube group. A condenser and a plurality of horizontally arranged heat transfer tubes are configured so that the fluid to be cooled is turned back to the adjacent heat transfer tube group at the tube end and sequentially flows laterally, and the refrigerant is stored outside the heat transfer tubes. Provided is a shell-and-tube type evaporator having an evaporator in which a tube diameter of a downstream heat transfer tube group is smaller than that of an upstream heat transfer tube group.

In the condenser used in the present invention, the tube diameter of the lower heat transfer tube group is smaller than that of the upper heat transfer tube group, so that the heat transfer area of the lower heat transfer tube group is increased, and By reducing the pipe diameter, the flow velocity of the cooling fluid in the pipe is increased and the heat transmission coefficient is increased.Therefore, the liquid film around the heat transfer pipe becomes thicker and condensed due to the flow of the liquid refrigerant condensed in the upper heat transfer pipe. The condensing performance in the lower heat transfer tube group where the heat transfer rate decreases is improved.

In the condenser according to the present invention, the upper and lower heat transfer tube groups in which the cooling fluid is folded back at the tube ends of the heat transfer tubes have three or more stages, and the tube diameters of the lower heat transfer tube groups are successively reduced to the lower diameter. It is possible to improve the condensation performance in the heat transfer tube group.

Further, in the condenser according to the present invention, if a condensate removing plate that is inclined obliquely downward when viewed from the end surface of the heat transfer tube group is arranged between the heat transfer tube groups, the heat transfer tubes condense above. Since the liquid refrigerant that is about to flow down to the lower heat transfer tube is received obliquely downward by the condensate exclusion plate that inclines obliquely downward, the liquid film of the liquid refrigerant adhering to the surface of the lower heat transfer tube becomes thicker. Is preferable, and it is preferable for improving the condensing performance in the lower heat transfer tube.

Further, when the condensate exclusion plate having a chevron-shaped structure inclined to both sides is adopted, the liquid refrigerant which is going to flow down to the lower heat transfer tube is different in two directions depending on the chevron-shaped condensate exclusion plate. The liquid refrigerant is not collected in one place by being divided into two, so the liquid refrigerant is effectively removed from the heat transfer tube group,
This is effective in suppressing a decrease in heat transfer coefficient in the lower heat transfer tube group.

Further, by arranging the above-mentioned condensate-discharging plates in a plurality of stages which are vertically spaced, it is possible to effectively remove the liquid refrigerant from the heat transfer tube group.

Next, in the evaporator according to the present invention, since the tube diameter of the downstream heat transfer tube group is smaller than that of the upstream heat transfer tube group, the heat transfer area in the downstream heat transfer tube group is increased,
Moreover, since the flow velocity of the fluid to be cooled in the pipe is increased and the heat transmission coefficient is increased by reducing the pipe diameter, the heat transfer performance in the path on the outlet side of the water to be cooled is improved.

In the evaporator of the present invention, three or more laterally adjacent heat transfer tube groups that are folded back at the tube ends are arranged side by side, and the tube diameters of the heat transfer tube groups are sequentially reduced from the downstream heat transfer tube group. With such a configuration, the heat transfer performance can be improved in the downstream heat transfer tube group.

Further, in the evaporator of the present invention, if the structure in which the height of the heat transfer tube group is gradually lowered in the downstream heat transfer tube group is adopted, the downstream side is affected by the rise of the gas-liquid interface in the upstream heat transfer tube group. Even if the gas-liquid interface in the heat transfer tube group on the side is lowered, the upper heat transfer tube in the heat transfer tube group on the downstream side is prevented from being exposed from the liquid refrigerant into the gas phase refrigerant, and the heat transfer tube between the liquid refrigerant and the heat transfer tube is prevented. It is preferable because heat exchange can be performed well.

In the refrigerator having the condenser and the evaporator of the present invention having the above-mentioned characteristics, the performance of the refrigerator can be improved by improving the heat transfer performance in the condenser and the evaporator, and The structure can be made compact.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A condenser for a refrigerator and an evaporator for a refrigerator according to the present invention will be specifically described below based on the illustrated embodiments. In the following embodiments, the same parts as those in the structure of the conventional apparatus shown in FIGS. 10 to 12 are designated by the same reference numerals, and the duplicated description thereof will be omitted.

(First Embodiment) First, a refrigerator condenser according to a first embodiment of the present invention shown in FIG. 1 will be described. The refrigerator condenser 20 according to the first embodiment has one
Cooling water flows into the heat transfer tube 21 from one end of the lower heat transfer tube group 21 which is the pass, turns back at the other end, flows in from the other end of the upper second path heat transfer tube group 22 and flows out from one end. It consists of 2 passes. Then, the pipe diameter of the lower heat transfer pipes 21 group corresponding to the first pass is set to the upper heat transfer pipe 22 of the second pass.
It is smaller than the pipe diameter of. As the tube diameter, for example, the upper heat transfer tube 22 has a diameter of 19 mm, and the lower heat transfer tube 21 has a diameter of 16 mm.

As described above, in the condenser 20 according to the first embodiment, the number of the lower heat transfer tubes 21 is about 40%.
The heat transfer area is increased by 20 to 30% from the heat transfer area of the upper heat transfer tube group 22. In the refrigerator condenser 20 according to the first embodiment, the condensing performance of the lower heat transfer tube group 21 is improved by increasing the heat transfer area and the heat transmission coefficient of the lower heat transfer tube group 21.

(Second Embodiment) Next, a refrigerator condenser according to a second embodiment of the present invention shown in FIG. 2 will be described. In the second embodiment, as shown in FIG. 6B, the pipe is folded back so that the cooling water flows through the heat transfer pipe group in four passes, and the lowest heat transfer pipe 21 corresponding to one pass is formed.
The group is composed of heat transfer tubes having a smaller diameter than the other groups of heat transfer tubes 22 in 2 to 4 passes. In the condenser 20 for a refrigerator of the second embodiment, the heat transfer area and the heat transmission coefficient of the heat transfer tubes 21 forming the lowest one path are increased, and the heat transfer tubes 21 of the first path are condensed. Performance has been improved.

(Third Embodiment) Next, a refrigerator condenser according to a third embodiment of the present invention shown in FIG. 3 will be described. In the third embodiment, the cooling water flowing through the heat transfer tube is configured to flow in three passes as shown in FIG. (B), and the heat transfer tube in the lower pass has a smaller tube diameter. That is, for example, the diameter of the heat transfer tube 21 that forms one path at the bottom is 12 mmφ and the heat transfer tube 23 that forms two paths.
The diameter of the tube is 16 mmφ, and the tube diameter of the heat transfer tube 22 forming three passes is 19 mmφ. As described above, in the third embodiment, the heat transfer tubes in the lower path have smaller tube diameters, the heat transfer area and the heat transmission coefficient of the lower heat transfer tube group are increased, and the heat transfer tube group in the lower path is increased. The condensation performance in is improved.

(Fourth Embodiment) Next, a refrigerator condenser according to a fourth embodiment of the present invention shown in FIG. 4 will be described. In the fourth embodiment, the liquid removal plate 24 is arranged inside the condenser 20, and the tube diameter of the lowest heat transfer tube 21 in the heat transfer tube group partitioned by the liquid removal plate 24 is set to be small. There is.

In FIG. 4, the liquid removal plate 24 is the condenser 2
Two sheets are attached in 0 at an inclination angle α (α = 0 to 60 °), and the heat transfer tubes inside are divided into three tube groups. Inlet pipe 8
The gas refrigerant flowing in from flows into each tube group as shown by the arrow. Of the tube groups divided by the liquid removal plate 24, the heat transfer tubes 21 forming the lowest tube group are the heat transfer tubes 2 of the other tube groups.
The diameter is smaller than 2.

In the condenser according to the fourth embodiment, since the slanted liquid excluding plate 24 is arranged between the heat transfer tube groups, the liquid refrigerant condensed by heat exchange with the upper heat transfer tubes moves downward. When trying to flow down to the heat transfer tube located, it is prevented that the liquid film of the liquid refrigerant adhered to the surface of the heat transfer tube below is received by the liquid excluding plate 24 and flows along the inclination.

In addition, since the lowermost heat transfer tubes 21 grouped by the liquid exclusion plate 24 are composed of heat transfer tubes having a small diameter,
Its condensation performance has been improved. Although FIG. 4 shows the liquid expulsion plate 24 that is inclined in one direction, as shown in FIG. 5, a mountain-shaped liquid expulsion plate 25 that is inclined from the apex of the center to both sides allows the liquid refrigerant to flow down to both sides. It may be dispersed.

(Fifth Embodiment) Next, a refrigerator evaporator according to a fifth embodiment of the present invention shown in FIG. 6 will be described. In the refrigerator evaporator 30 according to the fifth embodiment,
Among the plurality of heat transfer tube groups A to D arranged in the lateral direction, the cooled water flowing from the inflow port 12 is turned back at the tube end and flows.
The tube diameter of the heat transfer tube 32 that constitutes the most downstream heat transfer tube group D is smaller than the tube diameters of the heat transfer tubes 31 of the other heat transfer tube groups A to C. Thus, the heat transfer performance is improved by increasing the heat transfer area and the heat transmission coefficient in the most downstream heat transfer tube group D. As described above, in the evaporator for a refrigerator according to the fifth embodiment, the heat transfer performance is prevented from being deteriorated in the heat transfer tube group at the most downstream side of the evaporator in which the temperature difference between the water to be cooled and the refrigerant becomes small. .

(Sixth Embodiment) Next, a refrigerator evaporator according to a sixth embodiment of the present invention shown in FIG. 7 will be described. In the evaporator according to the sixth embodiment, the downstream two heat transfer tubes among the plurality of heat transfer tube groups E to H arranged in the lateral direction in which the water to be cooled flowing from the inflow port 12 is folded back at the tube end and flows. The diameter of the heat transfer tubes 32 forming the groups G and H is smaller than the diameter of the heat transfer tubes 31 of the other heat transfer tube groups E and F. In this way, the heat transfer area and the heat transmission coefficient in the downstream heat transfer tube groups G and H are increased to improve the heat transfer performance.

(Seventh Embodiment) Next, a refrigerator evaporator according to a seventh embodiment of the present invention shown in FIG. 8 will be described. In the evaporator according to the seventh embodiment, of the heat transfer tube groups I to K arranged in the lateral direction, the tube diameters of the heat transfer tubes 33 and 32 forming the downstream heat transfer tube groups J and K are sequentially reduced. Is. That is, the tube diameter of the heat transfer tube 33 of the heat transfer tube group J (eg: 16 mm) is smaller than the tube diameter of the heat transfer tube 31 of the heat transfer tube group I (eg: 19 mm), and the heat transfer tube 32 of the heat transfer tube group K.
The tube diameter (e.g., 12 mm) is smaller than the tube diameter of the heat transfer tube 33, and the heat transfer area and the heat transmission coefficient are increased in the downstream heat transfer tube group.

(Eighth Embodiment) Next, an evaporator for a refrigerator according to an eighth embodiment shown in FIG. 9 will be described. In the evaporator according to the eighth embodiment, the heat transfer tubes constituting the heat transfer tube groups L to O arranged in the lateral direction have the heights of the upstream heat transfer tubes increasing in order.

By making the upstream heat transfer tube group higher and the downstream heat transfer tube group lower, the downstream heat transfer tube is influenced by the rise of the gas-liquid interface of the refrigerant in the upstream heat transfer tube group. Even if the gas-liquid interface of the group is lowered, the uppermost heat transfer tube is prevented from being exposed in the gas-phase refrigerant.

The heat transfer tubes 31 of the heat transfer tube groups L to N have the same diameter, but in the most upstream heat transfer tube group L, the heat transfer tube group L is the same.
The interval between the heat transfer tubes 31 configuring the heat transfer tubes 31 is larger than the interval between the heat transfer tubes 31 in the downstream heat transfer tube groups M and N. In this way, the heat transfer tubes 3 in the upstream heat transfer tube group L
By increasing the distance between the heat transfer tubes 31, the vaporized refrigerant can easily escape between the heat transfer tubes 31, thereby preventing the bubbles of the refrigerant from clinging around the heat transfer tubes 31 submerged in the refrigerant liquid, and thus improving the heat transfer coefficient. Is improving.

Further, in the evaporator according to the eighth embodiment, the tube diameter of the heat transfer tube 32 forming the most downstream heat transfer tube group O is set to the tube diameter of the heat transfer tube 31 forming the upstream heat transfer tube group L to N. The heat transfer area and the heat transmission coefficient in the most downstream heat transfer tube group O are made smaller, and the temperature difference between the water to be cooled and the refrigerant becomes smaller.

Although the above description has been given based on the embodiments of the present invention, the present invention is not limited to these embodiments, and various modifications and changes are made within the scope of the present invention shown in the claims. Needless to say, may be added. For example, in each of the embodiments, the condenser and the evaporator are individually described, but the condenser and the evaporator according to these embodiments may be appropriately combined to configure the refrigerator of the present invention. The heat transfer efficiency of the condenser and the evaporator according to the present invention is improved by about 10%, respectively, and the performance (coefficient of performance: COP) of the refrigerator equipped with the condenser and the evaporator according to the present invention can be improved by about 1%. .

[0036]

As described above, according to the present invention, the cooling fluid is folded back at the tube ends into a plurality of horizontally arranged heat transfer tubes to flow from the lower heat transfer tube group to the upper heat transfer tube group. A condenser of shell-and-tube type configured to flow the refrigerant from above to the outside of the heat transfer tube, wherein the tube diameter of the lower heat transfer tube group is smaller than the tube diameter of the upper heat transfer tube group, Shell-and-tube type configured so that the fluid to be cooled is folded back to the adjacent heat transfer tube group in the horizontally arranged heat transfer tubes at the end of the tube and sequentially flows laterally, and the refrigerant is accommodated outside the heat transfer tubes. And an evaporator in which the tube diameter of the downstream heat transfer tube group is smaller than that of the upstream heat transfer tube group.

In the condenser used in the present invention, the tube diameter of the lower heat transfer tube group is made smaller than that of the upper heat transfer tube group so that the heat transfer area of the lower heat transfer tube group is increased and the heat transmission coefficient is increased. Since it has been increased, the liquid film around the heat transfer tube becomes thicker due to the flow of the liquid refrigerant condensed in the upper heat transfer tube, which improves the condensation performance in the lower heat transfer tube group, which tends to lower the condensation heat transfer coefficient. .

Further, in the condenser according to the present invention, in the structure in which the condensate excluding plate which is inclined obliquely downward when viewed from the end surface of the heat transfer tube group is arranged between the heat transfer tube groups, the heat transfer tube above is formed. The liquid refrigerant that has condensed and is about to flow down to the lower heat transfer tube is received obliquely downward by the condensate exclusion plate that inclines obliquely downward, so the liquid film of the liquid refrigerant adhering to the surface of the lower heat transfer tube becomes thicker. Can be prevented, and the condensation performance in the lower heat transfer tube can be improved.

Further, in the case where the condensate removing plate having a mountain-like structure inclined to both sides is adopted, the liquid refrigerant to be flown down toward the lower heat transfer tube is different depending on the conical condensing plate. Since the liquid refrigerant is divided into two directions and the liquid refrigerant does not collect at one place, the liquid refrigerant is effectively removed from the heat transfer tube group, and the lowering of the heat transfer coefficient in the lower heat transfer tube group is effectively suppressed.

Further, in the structure in which the above-mentioned condensate-discharging plate is arranged in a plurality of stages vertically spaced, it is possible to effectively remove the liquid refrigerant from the heat transfer tube group.

Next, in the evaporator according to the present invention, the tube diameter of the downstream heat transfer tube group is made smaller than that of the upstream heat transfer tube group,
Since the heat transfer area in the downstream heat transfer tube group is increased to increase the heat transmission coefficient, the heat transfer performance in the path on the outlet side of the cooled water is improved.

In the evaporator of the present invention, three or more laterally adjacent heat transfer tube groups that are folded back at the tube ends are arranged side by side, and the tube diameters of these heat transfer tube groups are sequentially reduced to those of the downstream heat transfer tube group. In the configuration having the above, the heat transfer performance is improved in the downstream heat transfer tube group.

Further, in the evaporator of the present invention, when the structure in which the height of the heat transfer tube group is gradually lowered in the downstream heat transfer tube group is adopted, the vapor-liquid interface rise in the upstream heat transfer tube group is affected. Even if the gas-liquid interface in the downstream heat transfer tube group decreases, the upper heat transfer tube in the downstream heat transfer tube group is prevented from being exposed from the liquid refrigerant into the gas phase refrigerant, and the liquid refrigerant and the heat transfer tube are prevented. Good heat exchange with.

In the refrigerator having the condenser and the evaporator of the present invention having the above characteristics, the performance of the refrigerator can be improved by improving the heat transfer performance in the condenser and the evaporator. The structure can be made compact.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a condenser according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a condenser according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing the configuration of a condenser according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of a condenser according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a modified example of the condenser according to the fourth embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of an evaporator according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing the structure of an evaporator according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view showing the structure of an evaporator according to a seventh embodiment of the present invention.

FIG. 9 is a sectional view showing the structure of an evaporator according to an eighth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a configuration of a turbo refrigerator.

11 is a sectional view of the condenser taken along line II-II in FIG.

FIG. 12 is a sectional view showing the structure of a conventional evaporator.

[Explanation of symbols]

1 condenser 2 evaporator 3 Centrifugal compressor 4 containers 5 heat transfer tubes 6 Inlet 7 Outlet 8 inlet tubes 9 outlet pipe 10 heat transfer tubes 11 Expansion valve 12 Inlet 13 Outlet 20 Refrigerator condenser 21 heat transfer tube 22 heat transfer tube 23 Heat Transfer Tube 24 liquid removal plate 25 liquid removal plate 30 Refrigerator evaporator 31 heat transfer tube 32 heat transfer tube 33 heat transfer tube

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinori Shirakata             3-1, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi             Address Mitsubishi Heavy Industries Co., Ltd. (72) Inventor Kenji Ueda             3-1, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi             Address Mitsubishi Heavy Industries Co., Ltd.

Claims (9)

[Claims] 1. A cooling fluid is folded back at a pipe end into a plurality of horizontally arranged heat transfer tubes to flow from a lower heat transfer tube group to an upper heat transfer tube group, and a refrigerant is flown outside the heat transfer tube from above to below. A shell-and-tube type condenser configured to flow, in which the lower heat transfer tube group has a smaller tube diameter than the upper heat transfer tube group, and a plurality of horizontally arranged heat transfer tubes. A shell-and-tube type evaporator configured so that a fluid to be cooled is folded back to the adjacent heat transfer tube group at the end of the tube and sequentially flows laterally and a refrigerant is stored outside the heat transfer tube in the tube. An evaporator having a tube diameter of the group smaller than that of the upstream heat transfer tube group. 2. A cooling fluid is folded back at a pipe end into a plurality of horizontally arranged heat transfer tubes to flow from a lower heat transfer tube group to an upper heat transfer tube group and a refrigerant is flown outside the heat transfer tube from above to below. What is claimed is: 1. A shell-and-tube type condenser configured to flow, wherein a tube diameter of a lower heat transfer tube group is smaller than that of an upper heat transfer tube group. 3. The upper and lower heat transfer tube groups in which the cooling fluid is folded back at the tube ends of the heat transfer tubes have three or more stages, and the tube diameters of the lower heat transfer tube groups are sequentially reduced. The refrigerator condenser described. 4. The refrigerator according to claim 2, further comprising a condensate exclusion plate disposed between the heat transfer tube groups, the condensate exclusion plate being inclined obliquely downward when viewed from the end surface of the heat transfer tube group. Condenser. 5. The condenser for a refrigerating machine according to claim 4, wherein the condensate drain plate is inclined in a mountain shape on both sides. 6. The condensate-discharging plate is arranged in a plurality of stages vertically spaced apart from each other.
The condenser for a refrigerator according to. 7. The heat transfer tubes are arranged horizontally in a plurality of horizontally arranged heat transfer tubes so that the fluid to be cooled is returned to the adjacent heat transfer tube groups at the tube ends and sequentially flowed laterally to accommodate the refrigerant outside the heat transfer tubes. A shell-and-tube type evaporator, wherein the tube diameter of the downstream heat transfer tube group is smaller than the tube diameter of the upstream heat transfer tube group. 8. A heat transfer tube group, which is folded back at the tube end, is formed by arranging three or more laterally adjacent heat transfer tube groups side by side, and the tube diameters of these heat transfer tube groups are successively reduced. The evaporator for refrigerators according to claim 7. 9. The evaporator for a refrigerator according to claim 7, wherein the height of the heat transfer tube group is gradually lowered toward the heat transfer tube group on the downstream side.