JPH0684270U - Capacitor for multi-stage refrigeration system - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the heat exchange performance of shell-and-coil type condensers for multistage refrigeration systems. A condenser comprises an outer shell 2 into which a low-temperature saturated refrigerant liquid is introduced from an upper inlet pipe 1, and a condensing coil 3 provided therein in which a high-temperature saturated refrigerant vapor is flowed and which is vertically arranged. , An inner shell 4 having an upper part 4a closed and a lower part 4b opened and arranged in the condenser coil 3, and a refrigerant outlet pipe 5 arranged in the inner shell 4 and opened to the outside of the outer shell 2. It has and. [Effect] A reliable cascade flow can be obtained between the coil rows of the condenser coil 3, and the refrigerant liquid in a fluid state is always in contact with the coil surface, so that sufficient fluidity and turbulence are obtained not only in the upper portion of the coil but also in the lower portion. A certain boiling phenomenon is obtained, and the heat transfer coefficient as a whole is significantly improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a condenser for a multistage refrigeration system in which a coil through which a refrigerant vapor is flown is vertically arranged in an outer cylinder into which a refrigerant liquid is introduced.

[0002]

[Prior art]

 For example, a condenser used in a dual refrigeration system that cools the refrigerant vapor of the low temperature side refrigeration cycle with the refrigerant liquid of the high temperature side refrigeration cycle to liquefy the refrigerant vapor and evaporate the refrigerant liquid is a shell-and-coil condenser, Double-tube capacitors, multilayer capacitors, etc. have been conventionally known.

Among them, the conventional shell-and-coil type capacitor has a small size, no liquid return, and an appropriate price, but has a drawback of poor heat exchange performance. As such a condenser, for example, as shown in FIG. 2, a condenser coil 3 and an inner pipe 5 are arranged in a shell 2, and a refrigerant liquid is introduced from an inlet pipe 1, whereby a refrigerant vapor in the coil 3 is removed. There is one in which the refrigerant liquid is cooled and liquefied, and the refrigerant liquid is evaporated by this heat exchange and discharged from the inner pipe 5. In the condenser of this structure, most of the refrigerant liquid collects in the shell 2 without directly contacting the condenser coil 3. In such a state, in the portion close to 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 in the lower portion rise. By doing so, since the bubble is strongly disturbed by the heat transfer surface, an active boiling phenomenon occurs and an extremely high heat transfer coefficient is obtained. However, in the lower part, the rise of boiling bubbles gradually decreases and the turbulence and fluidity in the liquid decreases, so even if boiling occurs on the coil surface, heat transfer is higher than in the upper part. The rate drops significantly. Further, on the liquid surface, the condenser coil 3 is covered with the vaporized vapor of the refrigerant liquid, and heat exchange is performed between the gas and the solid, so that the heat transfer coefficient is extremely low. As a result, the capacitor of this structure has a problem of poor heat exchange performance as a whole.

On the other hand, the double-tube condenser has a good heat exchange performance and a low price, but has a drawback that it has a large size and causes liquid return due to a change in the state of heat balance. Further, although the multilayer capacitor has an advantage of being extremely small in size, its greatest drawback is that it has liquid reflow and is very expensive.

[0005]

[Problems to be solved by the device]

 An object of the present invention is to solve the above problems in the prior art and to provide a condenser for a multi-stage refrigeration system that is compact, has no liquid return, is suitable in price, and has improved heat exchange performance.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention relates to a condenser for a multi-stage refrigeration system in which a coil through which a refrigerant vapor is flown is vertically arranged in an outer cylinder into which a refrigerant liquid is introduced, in which an upper part is closed and a lower part is opened. It is characterized by having an inner cylinder arranged along the inner side of the coil, and an inner pipe having an upper opening and arranged in the inner cylinder and guided to the outside of the outer cylinder.

[0007]

[Action]

 According to the present invention, the coil through which the refrigerant vapor flows is arranged vertically in the outer cylinder into which the refrigerant liquid is introduced, and the inner cylinder with the upper part closed and the lower part opened along the inside of the coil. Since the coil is disposed, the coil is 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 sequentially flows down in cascade in the respective gaps of the coils vertically installed in the gap due to 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 portion, 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 portion of the coil but also in the lower portion, heat exchange with a good heat transfer coefficient is performed overall, and heat exchange performance is improved. Then, the refrigerant liquid sequentially evaporates while flowing down.

On the other hand, since the lower part of the inner cylinder provided in the coil is open, and the upper part is opened in the inner cylinder and is guided to the outside of the outer cylinder, the evaporated refrigerant vapor is evaporated. Enters the inner cylinder through the opening in the lower part of the inner cylinder, rises, and then enters the inner pipe through the upper opening and is sent out of the outer cylinder. In this case, the vaporized vapor ascends upward in the inner cylinder and enters the inner pipe, so that liquid return is extremely well prevented. Since such a capacitor is a shell-and-coil type, it is small in size and relatively inexpensive in price.

In the actual design, the inner diameter of the outer cylinder, the diameter of the coil, the outer diameter of the inner cylinder, etc. are almost the same as the refrigerant liquid flowing in a cascade shape on the coil depending on the flow rate of the cooling liquid, the heat exchange amount, etc. Determined to evaporate.

[0010]

【Example】

 FIG. 1 shows a structural example of a double-structure shell-and-coil type cascade capacitor used in a dual refrigeration cycle as a capacitor for a multi-stage refrigeration system of the embodiment. In the dual refrigeration cycle, the high temperature saturated refrigerant vapor that is compressed after absorbing heat from the outside on the secondary low temperature cycle side and liquefied is liquefied by the low temperature saturated refrigerant liquid that is liquefied and decompressed on the primary high temperature cycle side. To be done. The present condenser used in such a refrigeration cycle has 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 therein. The condenser coil 3 as a coil arranged in the up-and-down direction, the inner shell 4 as an inner cylinder arranged along the inside of the condenser coil 3 with the upper portion 4a closed and the lower portion 4b opened, and the upper portion 5a opened. A refrigerant outlet pipe 5 is provided inside the inner shell 4 and guided to the outside of the outer shell 2.

The diameters of the outer shell 2 and the inner shell 4 are such that when the condenser coil 3 is arranged between them, the resistance of the flow of the refrigerant liquid and its evaporated vapor does not become too large, and Is determined in consideration of the flow rate of the refrigerant liquid, the heat exchange amount, the number of coil windings, etc., so that the refrigerant flows down between the coils in a cascaded manner under its own weight and the evaporated refrigerant vapor is conveyed downward. If necessary, the gap in the space above the coil may be narrowed, or the gap between the inner and outer shells may be widened from the upper side to the lower side.

In the shell-and-coil type cascade capacitor having such a structure, the following operation and heat exchange are performed. The saturated refrigerant liquid introduced from the inlet pipe 1 drops onto the upper portion 4 a of the inner shell 4, and then diffuses radially, and flows down between the outer shell 2 and the inner shell 4 onto the condensing coil 3. Since the gap between each coil portion of the condenser coil 3 and the inner and outer shells is narrow as shown in the figure, resistance is generated in this portion for each coil, and the refrigerant liquid flows down while flowing around the upper and lower portions of each coil. , Sufficient cascade flow is obtained. In addition, when only the upper baffle plate is provided without providing the inner shell 4 as described above, a large amount of liquid flow that does not hit 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 condenser coil 3, and is sequentially evaporated, and most of the lower portion of the condenser coil 3 becomes refrigerant vapor. Since this refrigerant vapor is sealed by the refrigerant liquid flowing down from the upper part of the coil, it flows into the inner shell 4 through the lower opening 4b of the inner shell 4 and rises in it, so that the liquid content is sufficiently separated and only the refrigerant vapor is present. Becomes 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 part 3a of the condenser coil 3, cooled by the low-temperature refrigerant liquid and liquefied, and becomes a refrigerant liquid and is sent out from the lower part 3b of the condenser coil 3.

According to such a flow of the refrigerant liquid, the refrigerant liquid in a flowing state is always in contact with the surface of the coil, so that sufficient flow and turbulence are generated not only in the upper portion of the coil but also in the lower portion thereof. A certain boiling phenomenon is obtained, and the heat transfer coefficient as a whole is significantly improved.

[0015]

[Effect of device]

 As described above, according to the present invention, by adopting the double structure in which the inner cylinder is provided inside the outer cylinder, the heat exchange performance of the shell-and-coil type condenser used in the multi-stage refrigeration system can be significantly improved. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view and an internal front view showing the overall structure of a condenser for a multistage refrigeration system of an example.

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

[Explanation of symbols]

 2 Outer shell (outer cylinder) 3 Condensing coil (coil) 4 Inner shell (inner cylinder) 5 Inner tube

Claims (1)

[Scope of utility model registration request] 1. A condenser for a multi-stage refrigeration system in which a coil through which a refrigerant vapor is flowed is vertically arranged in an outer cylinder into which a refrigerant liquid is introduced. A condenser for a multi-stage refrigeration system, comprising: an inner cylinder provided; and an inner pipe having an upper opening, which is arranged in the inner cylinder and guided to the outside of the outer cylinder.