CN219713697U

CN219713697U - Cascade refrigerating system

Info

Publication number: CN219713697U
Application number: CN202320962935.2U
Authority: CN
Inventors: 刘其洋; 姚战立; 郭兴龙; 汤洪明
Original assignee: Suzhou Bapima Superconducting Technology Co ltd
Current assignee: Suzhou Bapima Superconducting Technology Co ltd
Priority date: 2023-04-25
Filing date: 2023-04-25
Publication date: 2023-09-19
Anticipated expiration: 2033-04-25

Abstract

The utility model discloses an overlapping refrigerating system, which comprises a first-stage compressor, a first-stage condenser, an evaporation condenser, a second-stage compressor and a second-stage precooler, wherein the first-stage condenser and the second-stage precooler are parallel flow heat exchangers and are integrated into a whole; the first-stage compressor, the first-stage condenser and the evaporation condenser are sequentially and circularly communicated, and a first-stage throttling element is arranged between the first-stage condenser and the evaporation condenser; the secondary compressor, the secondary precooler and the evaporative condenser are sequentially and circularly communicated, and a secondary throttling element and an air cooler are sequentially arranged on a circulating pipeline between the evaporative condenser and the secondary compressor. The cascade refrigeration system provided by the utility model has a good heat exchange effect, and the overall size of the whole refrigeration system can be reduced.

Description

Cascade refrigerating system

Technical Field

The utility model belongs to the technical field of refrigeration systems, and particularly relates to an overlapping type refrigeration system.

Background

Cascade refrigeration systems generally consist of two independent refrigeration systems, a high temperature system and a low temperature system, respectively. The refrigerant charged in the high temperature system is typically a medium temperature refrigerant such as R22, R404A, etc. While the cryogenic system is typically charged with a cryogenic refrigerant, such as R23, R508B, etc. The two systems are connected by means of an evaporation condenser, the refrigerant in the high-temperature system is compressed, condensed and expanded, and finally the cold energy generated by evaporation is transmitted to the low-temperature (cold end) system by the evaporation condenser, so that the refrigerant in the low-temperature (cold end) system achieves the condensing effect.

The condensing effect of the high temperature system refrigerant is a key factor affecting the final cooling capacity of the overall system. In the cascade refrigeration system, a copper tube fin type heat exchanger is generally adopted as a condenser of a high-temperature system, the heat exchange effect is common, and if the length and the width of the condenser are reduced, the thickness of the condenser can generate larger wind resistance to a fan.

Disclosure of Invention

In view of the above-described deficiencies of the prior art, the present utility model aims to: the cascade refrigeration system is good in heat exchange effect, and the overall size of the whole refrigeration system can be reduced.

In order to achieve the above object, the present utility model provides the following technical solutions:

the utility model provides an overlapping refrigerating system which comprises a first-stage compressor, a first-stage condenser, an evaporation condenser, a second-stage compressor and a second-stage precooler, wherein the first-stage condenser and the second-stage precooler are parallel-flow heat exchangers and are integrated into a whole; the first-stage compressor, the first-stage condenser and the evaporation condenser are sequentially and circularly communicated, and a first-stage throttling element is arranged between the first-stage condenser and the evaporation condenser; the secondary compressor, the secondary precooler and the evaporative condenser are sequentially and circularly communicated, and a secondary throttling element and an air cooler are sequentially arranged on a circulating pipeline between the evaporative condenser and the secondary compressor.

The utility model sets the first-stage condenser and the second-stage precooler as the parallel flow heat exchanger and integrates the two heat exchangers, on one hand, the characteristics of the parallel flow heat exchanger can be utilized to increase the heat exchange effect and reduce the overall dimension of the whole refrigeration system, and on the other hand, the condensation of the high-temperature system and the precooling of the low-temperature system can be simultaneously carried out by utilizing a set of fans, namely, the fans used by the first-stage condenser are utilized to provide precooled cold energy for the second-stage precooler, so that the cold energy can be saved and the integration level of the system can be improved.

The primary condenser comprises at least two first parallel flow heat exchangers which are connected in series, wherein one first parallel flow heat exchanger is provided with a first air inlet, and the other first parallel flow heat exchanger is provided with a first liquid outlet. The flow of the refrigerant can be increased by arranging at least two first parallel flow heat exchangers which are connected in series, so that the heat exchange effect is improved.

At least one partition board is arranged in each first parallel flow heat exchanger to form a compartment, and different compartments of the adjacent first parallel flow heat exchangers are connected in series through connecting pipes. The flow of the refrigerant can be increased by forming the compartments through the partition plates, and the heat exchange effect is further improved.

The adjacent parallel flow heat exchangers are connected through mounting buckles. The connecting mode of the mounting buckle is simple and feasible, and the mounting cost of the integration of different parallel flow heat exchangers is low.

The parallel flow heat exchangers of the primary condenser and the secondary precooler are arranged in parallel in a stacked mode, and an axial flow fan is arranged on one side of the secondary precooler. The axial flow fan is arranged on one side of the secondary precooler, and the flow direction of wind passes through the primary condenser and then passes through the secondary precooler. The primary condenser and the secondary precooler can be simultaneously carried out, the axial flow fan is used for exhausting (sucking air), the temperature of the air (air) is increased by heat exchange of the primary condenser, but the precooling effect of the secondary precooler is less influenced, and conversely, if the air passes through the secondary precooler first, the refrigerant condensing effect of the primary condenser can be influenced.

An air precooler is arranged on a circulating pipeline between the evaporative condenser and the primary compressor, and the air precooler is communicated with the air cooler. The refrigerating system is used for cooling air, the air is precooled by the air precooler and then cooled by the air cooler, so that liquid impact and cold waste can be avoided, and cold is saved.

The first-stage throttling element is an expansion valve, an electronic expansion valve or a thermal expansion valve can be selected, and the second-stage throttling element is a capillary tube. The secondary throttling element is used for throttling expansion of a low-temperature system, and a capillary tube can obtain a good throttling expansion effect in a lower-temperature state.

A liquid viewing mirror, a first filter and a liquid storage tank are sequentially arranged on a pipeline between the first-stage condenser and the first-stage throttling element; an oil separator is arranged between the secondary precooler and the evaporative condenser, and a second filter is arranged between the evaporative condenser and the secondary throttling element.

The parallel flow heat exchanger comprises a first collecting pipe, a second collecting pipe, shutter fins and a porous flat pipe, wherein the porous flat pipe is communicated with the first collecting pipe and the second collecting pipe, and the shutter fins are arranged on the porous flat pipe; the diameter of the collecting pipe of the secondary precooler and the width of the porous flat pipe are smaller than those of the primary condenser. The heat exchange requirement of the secondary precooler is low, and the size is reduced, so that the secondary precooler can be conveniently applied subsequently.

Compared with the prior art, the utility model has at least the following beneficial effects: the utility model sets the first-stage condenser and the second-stage precooler as the parallel flow heat exchanger and integrates the two heat exchangers, on one hand, the characteristics of the parallel flow heat exchanger can be utilized to increase the heat exchange effect and reduce the overall dimension of the whole refrigeration system, and on the other hand, the condensation of the high-temperature system and the precooling of the low-temperature system can be simultaneously carried out by utilizing a set of fans, namely, the fans used by the first-stage condenser are utilized to provide precooled cold energy for the second-stage precooler, so that the cold energy can be saved and the integration level of the system can be improved.

Drawings

In order to more clearly illustrate the technical solutions of specific embodiments of the present utility model, the drawings that are needed in the description of the embodiments will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is an internal block diagram of a cascade refrigeration system of the present utility model;

FIG. 2 is a schematic diagram of the cascade refrigeration system of the present utility model;

FIG. 3 is a schematic diagram of a condensing-pre-cooling module according to the present utility model;

fig. 4 is a side view of the condensing-precooling module of the present utility model;

FIG. 5 is a schematic view of the structure of the primary condenser of the present utility model;

FIG. 6 is a side view of the primary condenser of the present utility model;

FIG. 7 is a schematic diagram of a two-stage precooler of the present utility model;

fig. 8 is a side view of the secondary precooler of the present utility model.

Reference numerals: 1-a first stage compressor; 2-an evaporative condenser; a 3-stage compressor; 4-condensing-precooling module; 41-a first parallel flow heat exchanger; 411-first air inlet; 412-a first liquid outlet; 42-a second parallel flow heat exchanger; 421-second inlet; 422-a second air outlet; 401-a first header; 402-a second header; 403-shutter fins; 404-a porous flat tube; 400-connecting pipes; 410-a separator; 420-mounting a buckle; 43-an axial flow fan; 5-a primary throttling element; a 6-secondary throttling element; 7-an air cooler; 8-a liquid-viewing mirror; 9-a first filter; 10-a liquid storage tank; 11-oil separator; 12-a second filter; 13-air precooler.

Description of the embodiments

The following description of the embodiments of the present utility model will be made clearly and fully, and it is apparent that the embodiments described are only some, but not all, of the embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that, in order to describe the technical solution more specifically, the steps described in the present embodiment do not strictly correspond to the steps described in the summary of the utility model.

Examples

An cascade refrigeration system is provided, the operation of which is divided into three subsystems, a high temperature system, a low temperature system and an air system. Referring to fig. 1 and 2, there are included a first stage compressor 1 (high temperature system compressor), a first stage condenser (high temperature system condenser), an evaporation condenser 2, a second stage compressor 3 (low temperature system compressor), and a second stage precooler (low temperature system precooler). The primary condenser and the secondary precooler are parallel flow heat exchangers and are integrated into a whole to form a condensation-precooling module 4. Referring to fig. 3-6, the primary condenser comprises at least two first parallel flow heat exchangers 41 connected in series, and in this embodiment, the primary condenser comprises two first parallel flow heat exchangers 41, and in other embodiments, more or less. One of the first parallel flow heat exchangers 41 is provided with a first air inlet 411, and the other first parallel flow heat exchanger 41 is provided with a first liquid outlet 412. Referring to fig. 7-8 in combination, the secondary precooler includes a sheet of parallel flow heat exchanger, which is a second parallel flow heat exchanger 42, and a second air inlet 421 and a second air outlet 422 are provided on the second parallel flow heat exchanger 42. In this embodiment, the gas inlet and outlet or the liquid inlet and outlet are specifically adopted, and the arrangement is adjusted according to the type of the refrigerant and the refrigeration requirement, and is not limited. The evaporating condenser 2 is arranged conventionally, and can realize the structure of high-temperature system evaporation and low-temperature system condensation.

Referring to fig. 5 and 7, the first parallel flow heat exchanger 41 and the second parallel flow heat exchanger 42 each include a first header 401, a second header 402, shutter fins 403, and porous flat tubes 404, the porous flat tubes 404 communicating the first header 401 and the second header 402, the shutter fins 403 being mounted on the porous flat tubes 404. In this embodiment, the diameter of the collecting pipe of the second-stage precooler, that is, the second parallel flow heat exchanger 42 is smaller than the diameter of the collecting pipe of the first-stage condenser, that is, the first parallel flow heat exchanger 41, and the width of the porous flat pipe 404 of the second parallel flow heat exchanger 42 is smaller than the width of the porous flat pipe 404 of the first parallel flow heat exchanger 41. Wherein the diameter of the collecting pipe is the pipe diameter of the collecting pipe, and the width of the porous flat pipe 404 is the width of the porous channel in the arrangement direction. The heat exchange requirement of the secondary precooler is low, and the size of the heat exchanger is reduced, so that the subsequent application can be facilitated.

The two first parallel flow heat exchangers 41 are connected in series through the connecting pipe 400, and the flow of the refrigerant can be increased by arranging at least two first parallel flow heat exchangers 41 connected in series, so as to improve the heat exchange effect. In the refrigeration system, compared with a parallel connection mode, the heat exchange effect of a series connection mode is better. At least one partition 410 is disposed in each of the first parallel flow heat exchanger 41 and the second parallel flow heat exchanger 42 to form a compartment, in this embodiment, a partition 410, and the partition 410 divides the single-plate heat exchanger into two flows, so that the first-stage condenser has four flows and the second-stage precooler has two flows.

The formation of the compartments by the partition 410 may increase the flow path of the refrigerant to enhance the heat exchange effect. Different compartments of adjacent first parallel flow heat exchangers 41 are connected in series by connecting pipes 400. The second parallel flow heat exchanger 42 and the first parallel flow heat exchanger 41 and the two first parallel flow heat exchangers 41 are connected through the mounting buckle 420. The connection mode of the mounting buckle 420 is simple and feasible, and the cost is low. The primary condenser and the secondary precooler are arranged as the parallel flow heat exchanger and integrated, so that on one hand, the heat exchange effect can be increased by utilizing the characteristics of the parallel flow heat exchanger, the overall dimension of the whole refrigerating system is reduced, and on the other hand, the condensation of the high-temperature system and the precooling of the low-temperature system can be simultaneously carried out by utilizing a set of fans, namely, the precooling cold quantity is provided for the secondary precooler when the fans used by the primary condenser are used for exhausting air, the cold quantity can be saved, and the system integration level is improved.

Referring to fig. 2 and 4, a first parallel flow heat exchanger 41 and a second parallel flow heat exchanger 42 are arranged in parallel and stacked, and an axial flow fan 43 is provided at one side of the secondary precooler. The axial flow fan 43 is arranged at one side of the secondary precooler, and the wind flows through the first parallel flow heat exchanger 41 and the second first parallel flow heat exchanger 41 of the primary condenser, then through the second parallel flow heat exchanger 42 of the secondary precooler, and finally is discharged from the fan. The primary condenser and the secondary precooler can be used for condensing and precooling at the same time, the temperature of the air is increased due to heat exchange of the air passing through the primary condenser, but the precooling effect of the secondary precooler is less influenced, and conversely, if the air passes through the secondary precooler first, the refrigerant condensing effect of the primary condenser is influenced.

Referring to fig. 1 and 2 in combination with fig. 3 and 4, the first-stage compressor 1, the first-stage condenser and the evaporation condenser 2 are sequentially and circularly communicated, a first-stage throttling element 5 is arranged between the first-stage condenser and the evaporation condenser 2, and the first-stage throttling element 5 is an electronic expansion valve or a thermal expansion valve. The secondary compressor 3, the secondary precooler and the evaporative condenser 2 are sequentially and circularly communicated, a secondary throttling element 6 and an air cooler 7 are sequentially arranged on a circulation pipeline between the evaporative condenser 2 and the secondary compressor 3, and the secondary throttling element 6 is a capillary tube. The secondary throttling element 6 is used for throttling expansion of a low-temperature system, and a capillary tube can obtain a good throttling expansion effect in a lower-temperature state.

Referring to fig. 1 and 2, a liquid viewing mirror 8, a first filter 9 and a liquid storage tank 10 are sequentially arranged on a pipeline between the primary condenser and the primary throttling element 5; an oil separator 11 is arranged between the secondary precooler and the evaporative condenser 2, and a second filter 12 is arranged between the evaporative condenser 2 and the secondary throttling element 6. An air precooler 13 is arranged on the circulating pipeline between the evaporative condenser 2 and the primary compressor 1, and the air precooler 13 is communicated with the air cooler 7. The refrigerating system is used for cooling air, the air is precooled by the air precooler 13 and then is cooled by the air cooler 7, so that liquid impact and cold waste can be avoided, and cold is saved.

The principle of operation of the present utility model is elucidated by the present embodiment with reference to fig. 1 to 8:

principle of operation of high temperature system: the first-stage compressor 1 compresses a refrigerant such as R404A into a high-temperature and high-pressure gas, and then the gas is cooled by the two first parallel flow heat exchangers 41 and the axial flow fan 43 to become a high-pressure and low-temperature liquid, and then flows through the liquid viewing mirror 8, the first filter 9 and the liquid storage tank 10 to reach the first-stage throttling element 5, the liquid refrigerant R404A is expanded into a low-temperature and low-pressure gas-liquid mixture by the first-stage throttling element 5, and the cold energy is transferred to a low-temperature system in the evaporative condenser 2. The R404A after evaporation expansion has residual cold energy, the air precooler 13 is utilized to precool the air, and the R404A at low pressure and normal temperature finally returns to the first-stage compressor 1 to form circulation.

In the first-stage condenser: the refrigerant R404A enters the first header 401 from the first inlet 411, and flows into the second header 402 at the other end from the flat porous tube 404, forming a flow path. In the process, heat in the porous flat tube 404 is conducted to the shutter fins 403 to exchange heat with air effectively, so as to achieve the effect of cooling. The refrigerant flows through the two first parallel flow heat exchangers 41 through the connection pipe 400 to exchange heat with air, and is finally condensed into liquid to be discharged from the first liquid outlet 412.

Principle of operation of cryogenic systems: the two-stage compressor 3 compresses a refrigerant such as R23 into a high-temperature high-pressure gas, and then the gas is precooled through the second parallel flow heat exchanger 42 and the axial flow fan 43, separated from oil and gas in the oil separator 11, cooled in the evaporative condenser 2, and becomes a high-pressure low-temperature liquid. Then, the air flows through the second filter 12 to reach the secondary throttling element 6, and the liquid refrigerant R23 is expanded and depressurized by the throttling action of the secondary throttling element 6 to become low-pressure low-temperature R23, and finally the air is cooled in the air cooler 7 to become low-pressure normal-temperature R23, and the air returns to the secondary compressor 3 to form a cycle.

In the secondary precooler: the refrigerant R23 enters the first header 401 from the second inlet 421, flows into the second header 402 at the other end from the porous flat tube 404, and exchanges heat with air through the louver fins 403 and the porous flat tube 404. The separator divides the low temperature system precooler into two flows, and the refrigerant R23 after heat exchange is finally discharged from the second air outlet 422.

Principle of operation of air systems: the normal temperature dry air is precooled by an air precooler 13, and is cooled by an air cooler 7, and finally the low temperature dry air is formed.

Examples

The cascade refrigeration system provided in embodiment 1 is applied to a heat flow meter for refrigeration.

The above description of the embodiments is only intended to assist in understanding the method and core idea of the utility model. It should be noted that it will be apparent to those skilled in the art that various improvements and modifications can be made to the present utility model without departing from the principles of the utility model, and such improvements and modifications fall within the scope of the appended claims.

Claims

1. The cascade refrigeration system is characterized by comprising a first-stage compressor (1), a first-stage condenser, an evaporation condenser (2), a second-stage compressor (3) and a second-stage precooler, wherein the first-stage condenser and the second-stage precooler are parallel-flow heat exchangers and are integrated into a whole; the primary compressor (1), the primary condenser and the evaporative condenser (2) are sequentially and circularly communicated, and a primary throttling element (5) is arranged between the primary condenser and the evaporative condenser (2); the two-stage compressor (3), the two-stage precooler and the evaporative condenser (2) are sequentially and circularly communicated, and a two-stage throttling element (6) and an air cooler (7) are sequentially arranged on a circulating pipeline between the evaporative condenser (2) and the two-stage compressor (3).

2. Cascade refrigeration system according to claim 1, characterized in that the primary condenser comprises at least two first parallel flow heat exchangers (41) connected in series, wherein one of the first parallel flow heat exchangers (41) is provided with a first air inlet (411) and the other one of the first parallel flow heat exchangers (41) is provided with a first liquid outlet (412).

3. Cascade refrigeration system according to claim 2, characterized in that at least one partition (410) is provided in each of the first parallel flow heat exchangers (41) to form compartments, different compartments of adjacent first parallel flow heat exchangers (41) being connected in series by a connecting pipe (400).

4. Cascade refrigeration system according to claim 1 or 2, characterized in that adjacent parallel flow heat exchangers are connected by means of mounting snaps (420).

5. Cascade refrigeration system according to claim 1 or 2, characterized in that the parallel flow heat exchangers of the primary condenser and the secondary precooler are arranged in parallel and in a stack, and that an axial flow fan (43) is arranged on one side of the secondary precooler.

6. Cascade refrigeration system according to claim 1, characterized in that an air pre-cooler (13) is provided on the circulation line between the evaporation condenser (2) and the primary compressor (1), the air pre-cooler (13) being in communication with the air cooler (7).

7. Cascade refrigeration system according to claim 1, characterized in that the primary throttling element (5) is an expansion valve and the secondary throttling element (6) is a capillary tube.

8. Cascade refrigeration system according to claim 1 or 7, characterized in that a liquid viewing mirror (8), a first filter (9) and a liquid storage tank (10) are arranged in sequence on a pipeline between the primary condenser and the primary throttling element (5); an oil separator (11) is arranged between the secondary precooler and the evaporative condenser (2), and a second filter (12) is arranged between the evaporative condenser (2) and the secondary throttling element (6).

9. The cascade refrigeration system according to claim 1 or 2, characterized in that the parallel flow heat exchanger comprises a first header (401), a second header (402), shutter fins (403) and a porous flat tube (404), the porous flat tube (404) communicating the first header (401) and the second header (402), the shutter fins (403) being mounted on the porous flat tube (404); the diameter of the current collector of the secondary precooler and the width of the porous flat tube are smaller than those of the primary condenser.