JP2550541Y2 - Condenser for multistage refrigeration system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condenser for a multistage refrigeration system in which a coil through which refrigerant vapor flows is disposed in an outer cylinder into which refrigerant liquid is introduced.

[0002]

2. Description of the Related Art For example, as a condenser used in a binary refrigeration system in which a refrigerant vapor of a low-temperature refrigeration cycle is cooled by a refrigerant liquid of a high-temperature refrigeration cycle, the refrigerant vapor is liquefied, and the refrigerant liquid is evaporated. 2. Description of the Related Art A coil type capacitor, a double tube type capacitor, a multilayer type capacitor and the like have been conventionally known.

[0003] Among them, the conventional shell-and-coil type capacitor is small in size, has no liquid return, and is appropriate in price, but has a drawback that heat exchange performance is poor. As such a capacitor, for example, as shown in FIG.
A condenser coil 3 and an inner pipe 5 are provided in a shell 2, and a refrigerant liquid is introduced from an inlet pipe 1, whereby the refrigerant vapor in the coil 3 is cooled and liquefied. Some are evaporated and discharged from the inner tube 5. In the condenser having this structure, most of the refrigerant liquid accumulates in the shell 2 without directly contacting the condenser coil 3. In such a state, in the portion near the liquid surface of the liquid accumulated in the shell 2, in addition to the boiling phenomenon of the refrigerant liquid on the coil surface in that portion, the bubbles of the refrigerant vapor boiling at the lower portion rise. Since the heat transfer surface is strongly disturbed by the bubbles, an active boiling phenomenon occurs and an extremely high heat transfer coefficient is obtained. However, below that,
Since the rise of the boiling air bubbles gradually decreases and the turbulence and the fluidity in the liquid decrease, the heat transfer coefficient is greatly reduced as compared with the upper part even if the boiling phenomenon occurs on the coil surface. On the liquid level, the condensing coil 3 is covered with vaporized refrigerant liquid,
Because of the heat exchange between gas and solid, its heat transfer coefficient is very low. As a result, the capacitor having this structure has a problem that the heat exchange performance is poor as a whole.

[0004] On the other hand, the double-tube condenser has good heat exchange performance and is inexpensive, but has the disadvantage that it is large in size and liquid return occurs due to a change in the state of heat balance.
Further, the multilayer capacitor has the advantage of being extremely small in size, but the biggest drawback is that it has liquid return and is very expensive.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides a compact, multi-stage refrigeration system condenser with no liquid return, suitable price and improved heat exchange performance. That is the task.

[0006]

According to the present invention, there is provided a condenser for a multi-stage refrigeration system in which a coil through which refrigerant vapor is flown in an outer cylinder into which a refrigerant liquid is introduced is vertically arranged. An upper end is closed, a lower end is opened, and an inner tube is arranged along the inside of the coil; and an upper end is opened, is arranged in the inner tube, and is guided to the outside of the outer tube. And

[0007]

According to the present invention, a coil through which refrigerant vapor flows is vertically arranged in an outer cylinder into which a refrigerant liquid is introduced from an upper part, and an inner cylinder having an upper part closed and a lower part opened is formed along the inner side of the coil. Since the coils are arranged in such a manner, the coils are erected in the gap between the inner surface of the outer cylinder and the outer surface of the inner cylinder. For this reason, the refrigerant liquid introduced from the upper part of the outer cylinder flows down the respective stages of the coils vertically set up in the gap in a cascade manner by its own weight. That is, since there is an inner cylinder whose upper part is closed, a cascade flow is inevitably obtained in each row in the coil section, and the refrigerant liquid always contacts the coil in a flowing state. As a result, a boiling phenomenon with sufficient flow and turbulence is obtained not only in the upper part but also in the lower part of the coil, and heat exchange with a good heat transfer rate is performed as a whole, and the heat exchange performance is improved. Then, the refrigerant liquid evaporates sequentially while flowing down.

On the other hand, the lower part of the inner cylinder provided in the coil is open, and the inner pipe is provided with the upper part open in the inner cylinder and guided to the outside of the outer cylinder. Enters the inner cylinder through the opening at the lower part of the inner cylinder, rises, and further enters the inner pipe through the upper opening and is sent out of the outer cylinder. In this case, the evaporated vapor rises upward in the inner cylinder and enters the inner pipe, so that liquid return is prevented very well. And since such a capacitor is a shell and coil type,
The size is small and the price is relatively low.

In the actual design, the inner diameter of the outer cylinder, the diameter of the coil, the outer diameter of the inner cylinder, and the like are substantially determined by the flow of the refrigerant liquid, the amount of heat exchanged, and the like. It is determined to be.

[0010]

FIG. 1 shows a structural example of a double-shell-and-coil cascade condenser used in a binary refrigeration cycle as a condenser for a multistage refrigeration system according to an embodiment.
In the binary refrigeration cycle, the high-temperature saturated refrigerant vapor compressed after absorbing heat from the outside and vaporizing on the secondary low-temperature cycle side is liquefied by the low-temperature saturated refrigerant liquid liquefied and decompressed on the primary high-temperature cycle side. You. The condenser used in such a refrigeration cycle includes an outer shell 2 as an outer cylinder into which a low-temperature saturated refrigerant liquid is introduced from an upper inlet pipe 1, and a high-temperature saturated refrigerant vapor provided in the outer shell 2. A condensing coil 3 as a coil disposed in the direction, an upper shell 4a as an inner cylinder disposed along the inside of the condensing coil 3 with the upper part 4a closed and a lower part 4b opened, and an inner shell with an upper part 5a opened A refrigerant outlet pipe 5 disposed in the shell 4 and led to the outside of the outer shell 2.

The diameter of the outer shell 2 and the inner shell 4 is
When the condensing coil 3 is disposed between them, the refrigerant liquid flows down between the coils in a cascaded manner by its own weight without the resistance of the flow of the refrigerant liquid and the evaporated vapor being excessively increased, and the evaporated refrigerant The flow rate is determined in consideration of the flow rate of the refrigerant liquid, the amount of heat exchanged, the number of coil turns, and the like so that the vapor is conveyed downward. If necessary, the structure may be such that the gap in the space above the coil is narrowed or the gap between the inner and outer shells is increased from above to below.

The following operation and heat exchange are performed in the shell-and-coil cascade capacitor having such a structure. The saturated refrigerant liquid introduced from the inlet pipe 1 falls on the upper part 4 a of the inner shell 4, diffuses radially, and flows down onto the condensing coil 3 from between the outer shell 2 and the inner shell 4. Since the gap between each coil portion of the condensing coil 3 and the inner and outer shells is narrow as shown in the drawing, resistance is generated in this portion for each coil, and the refrigerant liquid flows down and over the upper and lower portions of each coil, A sufficient cascade flow is obtained. When only the upper baffle is provided without providing the inner shell 4 as described above, a large amount of liquid flow that flows down without hitting each coil is generated, and a sufficient cascade flow cannot be obtained.

The low-temperature refrigerant liquid exchanges heat with the high-temperature refrigerant vapor flowing inside while flowing down the outer surface of the condensing coil 3 and evaporates sequentially, and almost the lower part of the condensing coil 3 becomes refrigerant vapor. Since the refrigerant vapor is sealed by the refrigerant liquid flowing down the upper part of the coil, the refrigerant vapor flows into the inner shell 4 from the lower opening 4b of the inner shell 4, and rises therein.
The liquid component is sufficiently separated, becomes only refrigerant vapor, enters the inner tube 5, and is sent out of the condenser. On the other hand, the high-temperature saturated refrigerant vapor is introduced from the upper portion 3a of the condensing coil 3, cooled by the low-temperature refrigerant liquid, liquefied, and sent out from the lower portion 3b of the condensing coil 3 as a refrigerant liquid.

According to such a flow of the refrigerant liquid, the refrigerant liquid in a flowing state always comes into contact with the coil surface, so that not only the upper part but also the lower part of the coil have sufficient flow and turbulence. A boiling phenomenon is obtained, and the overall heat transfer coefficient is greatly improved.

[0015]

[Effects of the Invention] As described above, according to the present invention, the heat exchange performance of the shell-and-coil type condenser used in the multistage refrigeration system is greatly improved by adopting the double structure in which the inner cylinder is provided inside the outer cylinder. Can be done.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and an internal front view showing an entire structure of a condenser for a multistage refrigeration system according to an embodiment.

FIG. 2 is a sectional view and an internal front view showing the entire structure of a conventional condenser for a multistage refrigeration system.

[Explanation of symbols]

 2 outer shell (outer cylinder) 3 condensation coil (coil) 4 inner shell (inner cylinder) 5 inner tube

Claims (1)

(57) [Scope of request for utility model registration] 1. A condenser for a multistage refrigeration system in which a coil through which refrigerant vapor is flown is vertically arranged in an outer cylinder into which a refrigerant liquid is introduced, wherein the upper part is closed, the lower part is open, and the condenser is arranged along the inside of the coil. A condenser for a multistage refrigeration system, comprising: an inner tube provided; and an inner tube which is open in the upper portion, is disposed in the inner tube, and is guided outside the outer tube.