CN115406129B - Cascade refrigeration system and environmental test box - Google Patents
Cascade refrigeration system and environmental test box Download PDFInfo
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- CN115406129B CN115406129B CN202211116304.5A CN202211116304A CN115406129B CN 115406129 B CN115406129 B CN 115406129B CN 202211116304 A CN202211116304 A CN 202211116304A CN 115406129 B CN115406129 B CN 115406129B
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- 238000005057 refrigeration Methods 0.000 title claims abstract description 144
- 230000007613 environmental effect Effects 0.000 title claims abstract description 11
- 239000003507 refrigerant Substances 0.000 claims abstract description 85
- 238000001035 drying Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims 1
- 238000005265 energy consumption Methods 0.000 abstract description 7
- 230000009172 bursting Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L1/00—Enclosures; Chambers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L7/00—Heating or cooling apparatus; Heat insulating devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/31—Expansion valves
- F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/37—Capillary tubes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/40—Fluid line arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
- F25B43/003—Filters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
- F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
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- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Health & Medical Sciences (AREA)
- Clinical Laboratory Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
Abstract
The invention belongs to the technical field of environmental test boxes, and discloses a cascade refrigeration system and an environmental test box. When the first refrigeration loop of the cascade refrigeration system independently operates, high-temperature-level refrigerant discharged from the exhaust port of the first-stage compressor sequentially passes through the condenser, the first dry filter, the first electronic expansion valve and the high-temperature-level evaporator to return to the air inlet of the first-stage compressor, the first refrigeration loop further comprises an ambient temperature sensor, a first electromagnetic valve and a third electronic expansion valve, the first electromagnetic valve and the third electronic expansion valve are connected in series between the exhaust port of the first-stage compressor and the inlet of the high-temperature-level evaporator, when the ambient temperature sensor detects that the ambient temperature is lower than the ambient preset temperature, the first electromagnetic valve and the third electronic expansion valve are opened, the high-temperature-level refrigerant at the exhaust port of the first-stage compressor and the high-temperature-level refrigerant after passing through the first electronic expansion valve are mixed and then enter the high-temperature-level evaporator together, the heat output by the heater is partially replaced, and the energy consumption is reduced.
Description
Technical Field
The invention relates to the technical field of environmental temperature test boxes, in particular to a cascade refrigeration system and an environmental test box.
Background
Most environmental test chambers currently in the market employ compression refrigeration systems to simulate the ambient temperature. For environmental test chambers with test temperatures below-40 ℃, the following modes of cascade refrigeration systems are generally employed. The cascade refrigeration system consists of two sets of refrigeration systems of a high-temperature level (or 1 level) and a low-temperature level (or 2 level) which are coupled. The high-temperature-stage refrigeration system mainly comprises a compressor CM1, a high-temperature-stage condenser, a high-temperature-stage evaporator and a throttling device; the low-temperature-stage refrigeration system mainly comprises a compressor CM2, a low-temperature-stage condenser, a low-temperature-stage evaporator and a throttling device; when the cascade system is constantly operated at the temperature of over-20 ℃, only the high-temperature-level refrigerating system is operated, and the cold energy released by the high-temperature-level evaporator is required to be oppositely flushed for stable and balanced temperature, so that the high-temperature-level evaporator is provided with a heater, and when the cold energy released by the evaporator is excessive, the heater is started to heat and balance the temperature. This approach can result in excessive power consumption due to the need to additionally activate the heater to heat the evaporator.
Accordingly, there is a need for an cascade refrigeration system and environmental test chamber that addresses the problems of the prior art.
Disclosure of Invention
The invention aims to provide a cascade refrigeration system, which can reduce the energy consumption during the operation of the cascade refrigeration system.
To achieve the purpose, the invention adopts the following technical scheme:
the cascade refrigeration system comprises a first refrigeration loop, wherein the first refrigeration loop comprises a first-stage compressor, a condenser, a first dry filter, a first electronic expansion valve and a high-temperature-stage evaporator which are sequentially connected in series, high-temperature-stage refrigerant discharged from an exhaust port of the first-stage compressor sequentially passes through the condenser, the first dry filter, the first electronic expansion valve and the high-temperature-stage evaporator to return to an air inlet of the first-stage compressor, the first refrigeration loop further comprises an ambient temperature sensor, a first electromagnetic valve and a third electronic expansion valve, the first electromagnetic valve and the third electronic expansion valve are connected between an exhaust port of the first-stage compressor and an inlet of the high-temperature-stage evaporator in series, and when the ambient temperature sensor detects that the ambient temperature is lower than the ambient preset temperature, the first electromagnetic valve and the third electronic expansion valve are opened to mix the high-temperature-stage refrigerant discharged from the exhaust port of the first-stage compressor with the high-temperature-stage refrigerant passing through the first electronic expansion valve and then enter the high-temperature-stage evaporator together.
Optionally, the first refrigeration circuit further includes a first exhaust temperature sensor, a second electromagnetic valve and a first capillary tube, the outlet of the first drying filter and the outlet of the high-temperature-stage evaporator are connected in series with the second electromagnetic valve and the first capillary tube, the first exhaust temperature sensor is configured to detect the temperature of the exhaust port of the first-stage compressor, and when the first exhaust temperature sensor detects that the temperature of the exhaust port of the first-stage compressor is higher than the preset exhaust temperature of the first-stage compressor, the second electromagnetic valve is opened, so that the high-temperature-stage refrigerant flowing through the first capillary tube and the high-temperature-stage refrigerant at the outlet of the high-temperature-stage evaporator are sucked by the first-stage compressor after being mixed.
Optionally, the first refrigeration circuit further comprises a liquid-viewing mirror connected in series between the first dry filter outlet and the first electronic expansion valve.
Optionally, the first refrigeration circuit further comprises a condensing fan configured to dissipate heat from the condenser.
Optionally, the first refrigeration circuit further comprises a first pressure protection assembly configured to bring the pressure of the first refrigeration circuit within a preset range.
Optionally, the first refrigeration loop further comprises a third electromagnetic valve, a thermal expansion valve and an intermediate heat exchanger, and the third electromagnetic valve, the thermal expansion valve and the intermediate heat exchanger are connected in series between the outlet of the first drying filter and the air inlet of the primary compressor;
the cascade refrigeration system further comprises a second refrigeration loop, the second refrigeration loop comprises a secondary compressor, a precooler, an intermediate heat exchanger, a second dry filter, a second electronic expansion valve and a low-temperature-level evaporator which are sequentially connected in series, low-temperature-level refrigerant discharged from an exhaust port of the secondary compressor sequentially passes through the precooler, the intermediate heat exchanger, the second dry filter, the second electronic expansion valve and the low-temperature-level evaporator to return to an air inlet of the secondary compressor, and the intermediate heat exchanger is configured to enable the high-temperature-level refrigerant to cool the low-temperature-level refrigerant.
Optionally, the second refrigeration circuit further comprises an oil separator connected in series between the precooler and the intermediate heat exchanger, the oil separator being configured to convey oil in the low-temperature-stage refrigerant back to the secondary compressor.
Optionally, the second refrigeration circuit further includes a second exhaust temperature sensor, a fourth electromagnetic valve and a second capillary tube, the fourth electromagnetic valve and the second capillary tube are connected in series between the outlet of the second dry filter and the outlet of the low-temperature-stage evaporator, the second exhaust temperature sensor is configured to detect the temperature of the exhaust port of the secondary compressor, and when the second exhaust temperature sensor detects that the temperature of the exhaust port of the secondary compressor is higher than the preset exhaust temperature of the secondary compressor, the fourth electromagnetic valve is opened to enable the low-temperature-stage refrigerant flowing through the second capillary tube to be mixed with the low-temperature-stage refrigerant at the outlet of the low-temperature-stage evaporator and then sucked by the secondary compressor.
Optionally, the second refrigeration circuit further comprises a second pressure protection assembly configured to bring the second refrigeration circuit pressure within a preset range.
Another object of the invention is to provide an environmental test chamber that can be simulated at a lower temperature and with less energy consumption.
To achieve the purpose, the invention adopts the following technical scheme:
the environment test box comprises the cascade refrigeration system.
The beneficial effects are that:
according to the cascade refrigeration system provided by the invention, when the temperature required to be refrigerated is higher than minus 20 ℃, only the first refrigeration loop is constantly operated, a part of high-temperature high-pressure gaseous high-temperature-level refrigerant from the primary compressor is led out to the inlet of the high-temperature evaporator, and the heat output by the heater is partially replaced, so that the energy consumption is reduced, the high-temperature high-pressure gaseous high-temperature-level refrigerant from the primary compressor is led into the high-temperature evaporator through the first electromagnetic valve and the third electronic expansion valve in sequence, and the circulation of the high-temperature high-pressure gaseous high-temperature-level refrigerant can be regulated in an electrodeless manner through the third electronic expansion valve, so that the refrigeration temperature balance of the first refrigeration loop during independent operation is better controlled.
According to the environment temperature experimental box provided by the invention, when the temperature required to be refrigerated is above minus 20 ℃, the first refrigeration loop is independently operated, a part of high-temperature high-pressure gaseous high-temperature-level refrigerant from the first-stage compressor is led out to the inlet of the high-temperature evaporator, and the part of the high-temperature high-pressure gaseous high-temperature-level refrigerant replaces the heat output by the heater, so that the energy consumption is reduced, when the temperature required to be refrigerated is between minus 20 ℃ and minus 40 ℃, the first refrigeration loop and the second refrigeration loop are simultaneously operated, the first refrigeration loop and the second refrigeration loop are coupled through the intermediate heat exchanger, the low-temperature-level refrigerant in the second refrigeration loop is firstly cooled and cooled through the intermediate heat exchanger, and the temperature of the refrigerant in the second refrigeration loop is cooled again through the low-temperature evaporator, so that the environment experimental box can simulate lower temperature and the practicability of the environment experimental box is improved.
Drawings
Fig. 1 is a schematic diagram of a cascade refrigeration system provided by the present invention.
In the figure:
10. a first refrigeration circuit; 101. a first low voltage switch; 102. a first needle valve; 103. a first stage compressor; 104. a first exhaust gas temperature sensor; 105. a condenser; 106. a first high voltage switch; 107. an ambient temperature sensor; 108. a first electromagnetic valve; 109. a third electronic expansion valve; 110. a first dry filter; 111. a liquid viewing mirror; 112. a first electronic expansion valve; 113. a high temperature stage evaporator; 114. a second electromagnetic valve; 115. a first capillary; 116. a third electromagnetic valve; 117. a thermal expansion valve; 118. an intermediate heat exchanger;
20. a second refrigeration circuit; 201. a second low voltage switch; 202. a second needle valve; 203. a secondary compressor; 204. a second exhaust gas temperature sensor; 205. a precooler; 206. a second high voltage switch; 207. an oil separator; 208. a second dry filter; 209. a second electronic expansion valve; 210. a low temperature stage evaporator; 211. a fourth electromagnetic valve; 212. and a second capillary.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.
The present embodiment provides an cascade refrigeration system, as shown in fig. 1, the cascade refrigeration system includes a first refrigeration circuit 10, the first refrigeration circuit 10 includes a first-stage compressor 103, a condenser 105, a first drying filter 110, a first electronic expansion valve 112 and a high-temperature-stage evaporator 113 which are sequentially connected in series, a high-temperature high-pressure gaseous high-temperature-stage refrigerant discharged from an exhaust port of the first-stage compressor 103 sequentially passes through the condenser 105, the condenser 105 cools and liquefies the high-temperature high-pressure gaseous high-temperature-stage refrigerant, then the high-temperature-stage refrigerant is dried by the first drying filter 110 to remove excessive moisture, and then returns to an air inlet of the first-stage compressor 103 through the first electronic expansion valve 112 and the high-temperature-stage evaporator 113, so that a complete refrigeration cycle is completed, and cold energy generated by the first refrigeration circuit 10 is output through the high-temperature-stage evaporator 113. In order to ensure that the temperature output by the first refrigeration circuit 10 is constant, the first refrigeration circuit 10 further comprises an ambient temperature sensor 107, a first electromagnetic valve 108 and a third electronic expansion valve 109, the first electromagnetic valve 108 and the third electronic expansion valve 109 are connected in series between the exhaust port of the first-stage compressor 103 and the inlet of the high-temperature-stage evaporator 113, the ambient temperature sensor 107 is used for detecting the temperature in the environment, when the ambient temperature sensor 107 detects that the ambient temperature is lower than the environment preset temperature, the first electromagnetic valve 108 and the third electronic expansion valve 109 are simultaneously opened, and the high-temperature high-pressure gaseous high-temperature-stage refrigerant at the exhaust port of the first-stage compressor 103 and the high-temperature-stage refrigerant after passing through the first electronic expansion valve 112 are mixed and then enter the high-temperature-stage evaporator 113 together.
In the cascade refrigeration system provided in this embodiment, when the temperature required to be refrigerated is above-20 ℃, only the first refrigeration loop 10 is constantly operated, a part of the high-temperature high-pressure gaseous high-temperature-level refrigerant from the primary compressor 103 is led out to the inlet of the high-temperature evaporator, and the heat output by the heater is partially replaced, so that the energy consumption is reduced, and the high-temperature high-pressure gaseous high-temperature-level refrigerant from the primary compressor 103 is led into the high-temperature evaporator through the first electromagnetic valve 108 and the third electronic expansion valve 109 in sequence, and the circulation of the high-temperature high-pressure gaseous high-temperature-level refrigerant can be realized through the third electronic expansion valve 109, so that the refrigeration temperature balance during the independent operation of the first refrigeration loop 10 is better controlled.
Preferably, as shown in fig. 1, the first refrigeration circuit 10 further includes a first discharge temperature sensor 104, a second solenoid valve 114 and a first capillary tube 115, the outlet of the first dry filter 110 and the outlet of the high temperature stage evaporator 113 are connected in series with the second solenoid valve 114 and the first capillary tube 115, the first discharge temperature sensor 104 is used for detecting the temperature of the discharge port of the first stage compressor 103, when the first discharge temperature sensor 104 detects that the temperature of the discharge port of the first stage compressor 103 is higher than the preset discharge temperature of the first stage compressor 103, the second solenoid valve 114 is opened, so that the high temperature stage refrigerant flowing through the first capillary tube 115 is mixed with the high temperature stage refrigerant flowing through the outlet of the high temperature stage evaporator 113 and then sucked by the first stage compressor 103, thereby reducing the temperature of the high temperature stage refrigerant sucked by the first stage compressor 103 and reducing the discharge temperature of the first stage compressor 103.
Optionally, the first refrigeration circuit 10 further includes a liquid-viewing mirror 111, the liquid-viewing mirror 111 is connected in series between the outlet of the first dry filter 110 and the first electronic expansion valve 112, and the condition of the high-temperature-level refrigerant in the first refrigeration circuit 10 and the water content in the refrigerant can be observed through the liquid-viewing mirror 111, so that whether the high-temperature-level refrigerant in the first refrigeration circuit 10 has bubbles or flash gas and whether the high-temperature-level refrigerant needs to be filled can be easily observed through visual observation.
Optionally, the first refrigeration circuit 10 further includes a condensing fan, and the condensing fan is used for dissipating heat of the condenser 105, so as to improve the working efficiency of the condenser 105.
Preferably, the first refrigeration circuit 10 further includes a first pressure protection assembly for making the pressure of the first refrigeration circuit 10 within a preset range, and in particular, the pressure protection may be classified into an over-high pressure protection and an under-low pressure protection. The over-high pressure protection is to protect the pressure in the first refrigeration circuit 10 from burst and leakage by not exceeding the maximum safe pressure required by the system, and the under-low pressure protection is to protect the pressure in the first refrigeration circuit 10 from not falling below the minimum safe pressure required by the system by preventing the primary compressor 103 from drawing a vacuum. As shown in fig. 1, the first pressure protection assembly in this embodiment includes a first low-pressure switch 101, a first needle valve 102, and a first high-pressure switch 106, where the first low-pressure switch 101 is used to close the first refrigeration circuit 10 when the pressure in the first refrigeration circuit 10 is lower than the lowest pressure of the system, to prevent the compressor from vacuumizing, and the first high-pressure switch 106 is used to close the first refrigeration circuit 10 when the pressure in the first refrigeration circuit 10 is higher than the highest pressure of the system, to prevent the first refrigeration circuit 10 from bursting or leaking. The first low-voltage switch 101 and the first high-voltage switch 106 are respectively corresponding to one first needle valve 102 for adjusting the air flow.
Preferably, as shown in fig. 1, the first refrigeration circuit 10 further includes a third electromagnetic valve 116, a thermal expansion valve 117 and an intermediate heat exchanger 118, and the third electromagnetic valve 116, the thermal expansion valve 117 and the intermediate heat exchanger 118 are sequentially connected in series between the outlet of the first dry filter 110 and the air inlet of the first stage compressor 103; the cascade refrigeration system further comprises a second refrigeration loop 20, the second refrigeration loop 20 comprises a second compressor 203, a precooler 205, an intermediate heat exchanger 118, a second dry filter 208, a second electronic expansion valve 209 and a low-temperature-level evaporator 210 which are sequentially connected in series, low-temperature-level refrigerant discharged from an exhaust port of the second compressor 203 sequentially passes through the precooler 205, the intermediate heat exchanger 118, the second dry filter 208, the second electronic expansion valve 209 and the low-temperature-level evaporator 210 to return to an air inlet of the second compressor 203, and the intermediate heat exchanger 118 is used for cooling the low-temperature-level refrigerant by high-temperature-level refrigerant. In this embodiment, the first refrigeration circuit 10 and the second refrigeration circuit 20 are coupled through the intermediate heat exchanger, the high-temperature-level refrigerant in the first refrigeration circuit 10 cools the low-temperature-level refrigerant in the second refrigeration circuit 20 at first through the intermediate heat exchanger 118, and then the refrigerant in the second refrigeration circuit 20 cools again through the low-temperature evaporator, so that the temperature which can be simulated by the cascade refrigeration system is ensured to be lower, and the practicability of the cascade refrigeration system is improved.
Optionally, as shown in fig. 1, the second refrigeration circuit 20 further includes an oil separator 207, where the oil separator 207 is connected in series between the precooler 205 and the intermediate heat exchanger 118, and the oil separator 207 is used to separate oil in the low-temperature-stage refrigerant and send the oil back to the second-stage compressor 203.
Preferably, as shown in fig. 1, the second refrigeration circuit 20 further includes a second discharge temperature sensor 204, a fourth electromagnetic valve 211 and a second capillary tube 212, wherein the fourth electromagnetic valve 211 and the second capillary tube 212 are connected in series between the outlet of the second dry filter 208 and the outlet of the low-temperature-stage evaporator 210, the second discharge temperature sensor 204 is used for detecting the temperature of the discharge port of the second-stage compressor 203, and when the second discharge temperature sensor 204 detects that the temperature of the discharge port of the second-stage compressor 203 is higher than the preset discharge temperature of the second-stage compressor 203, the fourth electromagnetic valve 211 is opened to enable the low-temperature-stage refrigerant flowing through the second capillary tube 212 to be sucked by the second-stage compressor 203 after being mixed with the low-temperature-stage refrigerant at the outlet of the low-temperature-stage evaporator 210, thereby reducing the temperature of the high-temperature-stage refrigerant sucked by the second-stage compressor 203 and reducing the discharge temperature of the second-stage compressor 203.
Optionally, the second refrigeration circuit 20 further includes a second pressure protection component for keeping the pressure of the second refrigeration circuit 20 within a preset range. Specifically, the first pressure protection assembly in this embodiment includes a second low pressure switch 201, a second needle valve 202, and a second high pressure switch 206. The second low-voltage switch 201 is used for closing the second refrigeration circuit 20 when the pressure in the second refrigeration circuit 20 is lower than the lowest pressure of the system, preventing the secondary compressor 203 from vacuumizing, and the second high-voltage switch 206 is used for closing the second refrigeration circuit 20 when the pressure in the second refrigeration circuit 20 is higher than the highest pressure of the system, preventing the second refrigeration circuit 20 from bursting or leaking. The second low-voltage switch 201 and the second high-voltage switch 206 are respectively corresponding to a second needle valve 202 for adjusting the air flow.
Specifically, in this embodiment, the high-temperature-level refrigerant is R404A refrigerant, and R404A is a mixed refrigerant that does not destroy the ozone layer, so that the environment is protected, and the low-temperature-level refrigerant is R23 refrigerant.
Specifically, as shown in fig. 1, the refrigeration system has two modes in which the first refrigeration circuit 10 operates alone and the first refrigeration circuit 10 and the second refrigeration circuit 20 operate in combination.
The first refrigeration circuit 10 is mainly composed of a first low-pressure switch 101, a first needle valve 102, a first stage compressor 103, a first discharge temperature sensor 104, a condenser 105, a first high-pressure switch 106, an ambient temperature sensor 107, a first dry filter 110, a liquid-viewing mirror 111, a first electronic expansion valve 112, a high-temperature stage evaporator 113, a first solenoid valve 108, a third electronic expansion valve 109, a second solenoid valve 114, and a first capillary tube 115. The principle is shown in fig. 1, and the operation process is as follows: the high-temperature high-pressure gaseous high-temperature-level refrigerant discharged by the first-stage compressor 103 is divided into two paths, one path of the high-temperature high-pressure gaseous high-temperature-level refrigerant enters the condenser 105 and becomes liquid-state refrigerant, the liquid-state refrigerant passes through the drying filter and the liquid-viewing mirror 111 and is divided into two paths, one path of refrigerant passes through the first electronic expansion valve 112 and is throttled and depressurized to be low-temperature low-pressure high-temperature-level refrigerant, and the other path of refrigerant discharged by the compressor passes through the first electromagnetic valve and the connected third electronic expansion valve 109 and is mixed with the high-temperature-level refrigerant passing through the first electronic expansion valve 112 and then enters the high-temperature-level evaporator 113. The two mixed refrigerants absorb heat in the evaporator and become low-temperature low-pressure gas, and the gas is mixed with the other refrigerant liquid flowing through the liquid-viewing mirror 111 through the second electromagnetic valve 114 and the connected first capillary tube 115 and then is sucked again by the first-stage compressor 103 after being mixed with the refrigerant at the outlet of the high-temperature-stage evaporator 113, so that the whole refrigeration cycle is completed.
As shown in fig. 1, the combined operation mode mainly includes the first refrigeration circuit 10 and the second refrigeration circuit 20 operating in combination through the intermediate heat exchanger 118. The first refrigeration circuit 10 is mainly composed of a first low-pressure switch 101, a first needle valve 102, a first stage compressor 103, a first discharge temperature sensor 104, a condenser 105, a first high-pressure switch 106, an ambient temperature sensor 107, a first drier-filter 110, a liquid-viewing mirror 111, a third solenoid valve 116, an intermediate heat exchanger 118, a thermal expansion valve 117, a second solenoid valve 114, and a first capillary tube 115. The second refrigeration circuit 20 mainly comprises a second low-pressure switch 201, a second needle valve 202, a second compressor 203, a second discharge temperature sensor 204, a precooler 205, a second high-pressure switch 206, an oil separator 207, an intermediate heat exchanger 118, a second drier-filter 208, a second electronic expansion valve 209, a low-temperature-stage evaporator 210, a fourth solenoid valve 211 and a second capillary tube 212.
The principle in the combined operation mode is shown in fig. 1, and the operation process is as follows: the high-temperature high-pressure gaseous high-temperature-level refrigerant discharged by the primary compressor 103 enters the condenser 105 and becomes liquid refrigerant, after passing through the first dry filter 110 and the liquid-viewing mirror 111, the refrigerant is throttled and depressurized into low-temperature low-pressure refrigerant after passing through the third electromagnetic valve 116 and the thermal expansion valve 117, and enters the intermediate heat exchanger 118. The high-temperature-stage refrigerant in the intermediate heat exchanger 118 is cooled down to become low-temperature and low-pressure gas, which is sucked again by the compressor, thereby completing the high-temperature-stage refrigeration cycle. Meanwhile, the high-temperature high-pressure gaseous low-temperature-level refrigerant discharged by the secondary compressor 203 enters the precooler 205, is cooled, then enters the oil separator 207 and the intermediate heat exchanger 118, is cooled into liquid by the high-temperature-level refrigerant in the first refrigeration loop 10 in the intermediate heat exchanger 118, is split into two paths after passing through the second drying filter 208, and enters the low-temperature-level evaporator 210 after passing through the second electronic expansion valve 209, and is evaporated and cooled into gas by the air in the low-temperature-level evaporator 210. The other liquid passing through the second drier-filter 208 passes through the fourth solenoid valve 211 and the second capillary tube 212, is mixed with the refrigerant gas at the outlet of the low-temperature-stage evaporator 210, and is sucked again by the secondary compressor 203, thus completing the whole refrigeration cycle.
The embodiment also provides an environment test box which comprises the cascade refrigeration system. When the temperature of the environment temperature test box is required to be higher than minus 20 ℃, the first refrigeration loop 10 operates independently, a part of high-temperature high-pressure gaseous high-temperature-level refrigerant from the first-stage compressor 103 is led out to the inlet of the high-temperature evaporator, and the heat output by the heater is partially replaced, so that the energy consumption is reduced, when the temperature of the environment temperature test box is required to be lower than minus 20 ℃ to minus 40 ℃, the first refrigeration loop 10 and the second refrigeration loop 20 operate simultaneously, the first refrigeration loop 10 and the second refrigeration loop 20 are coupled through the middle heat exchanger, the low-temperature-level refrigerant in the second refrigeration loop 20 is cooled once through the high-temperature-level refrigerant in the first refrigeration loop 10 in the middle heat exchanger 118, the refrigerant in the second refrigeration loop 20 is cooled again through the low-temperature evaporator, the environment test box is ensured to be lower in simulated temperature, and the practicability of the environment test box is improved.
It is to be understood that the above examples of the present invention are provided for clarity of illustration only and are not limiting of the embodiments of the present invention. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the invention. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.
Claims (8)
1. The cascade refrigeration system is characterized by comprising a first refrigeration loop (10), wherein the first refrigeration loop (10) comprises a first-stage compressor (103), a condenser (105), a first dry filter (110), a first electronic expansion valve (112) and a high-temperature-stage evaporator (113) which are sequentially connected in series, high-temperature-stage refrigerant discharged from an exhaust port of the first-stage compressor (103) sequentially passes through the condenser (105), the first dry filter (110), the first electronic expansion valve (112) and the high-temperature-stage evaporator (113) and returns to an air inlet of the first-stage compressor (103), the first refrigeration loop (10) further comprises an ambient temperature sensor (107), a first electromagnetic valve (108) and a third electronic expansion valve (109), the first electromagnetic valve (108) and the third electronic expansion valve (109) are connected in series between an exhaust port of the first-stage compressor (103) and an inlet of the high-temperature-stage evaporator (113), when the ambient temperature sensor (107) detects that the ambient temperature is lower than the preset ambient temperature, the first electromagnetic expansion valve (108) and the third electronic expansion valve (109) are opened, mixing the high-temperature-level refrigerant at the exhaust port of the primary compressor (103) with the high-temperature-level refrigerant passing through the first electronic expansion valve (112) and then feeding the mixture into the high-temperature-level evaporator (113);
the first refrigeration loop (10) further comprises a liquid viewing mirror (111), and the liquid viewing mirror (111) is connected in series between the outlet of the first drying filter (110) and the first electronic expansion valve (112);
the first refrigeration circuit (10) further comprises a first pressure protection assembly configured to bring the pressure of the first refrigeration circuit (10) within a preset range;
the first pressure protection assembly comprises a first low-pressure switch (101), a first needle valve (102) and a first high-pressure switch (106), wherein the first low-pressure switch (101) is used for closing the first refrigeration circuit (10) when the pressure in the first refrigeration circuit (10) is lower than the lowest pressure of the system, the first high-pressure switch (106) is used for closing the first refrigeration circuit (10) when the pressure in the first refrigeration circuit (10) is higher than the highest pressure of the system, and the first low-pressure switch (101) and the first high-pressure switch (106) respectively correspond to one first needle valve (102) for adjusting the air flow.
2. The cascade refrigeration system of claim 1, wherein the first refrigeration circuit (10) further comprises a first discharge temperature sensor (104), a second solenoid valve (114) and a first capillary tube (115), the outlet of the first dry filter (110) is connected in series with the outlet of the high-temperature-stage evaporator (113) with the second solenoid valve (114) and the first capillary tube (115), the first discharge temperature sensor (104) is configured to detect a temperature of a discharge port of the first stage compressor (103), and the first discharge temperature sensor (104) detects that the discharge port temperature of the first stage compressor (103) is higher than a preset discharge temperature of the first stage compressor (103), the second solenoid valve (114) is opened to allow the high-temperature-stage refrigerant flowing through the first capillary tube (115) to be mixed with the high-temperature-stage refrigerant at the outlet of the high-temperature-stage evaporator (113) and sucked by the first stage compressor (103).
3. The cascade refrigeration system of claim 1, characterized in that the first refrigeration circuit (10) further comprises a condensing fan configured to dissipate heat from the condenser (105).
4. The cascade refrigeration system according to claim 1, characterized in that the first refrigeration circuit (10) further comprises a third solenoid valve (116), a thermostatic expansion valve (117) and an intermediate heat exchanger (118), the third solenoid valve (116), the thermostatic expansion valve (117) and the intermediate heat exchanger (118) being connected in series between the outlet of the first drier filter (110) and the air inlet of the primary compressor (103);
the cascade refrigeration system further comprises a second refrigeration loop (20), the second refrigeration loop (20) comprises a two-stage compressor (203), a precooler (205), an intermediate heat exchanger (118), a second drying filter (208), a second electronic expansion valve (209) and a low-temperature-level evaporator (210) which are sequentially connected in series, low-temperature-level refrigerant discharged from an exhaust port of the two-stage compressor (203) sequentially passes through the precooler (205), the intermediate heat exchanger (118), the second drying filter (208), the second electronic expansion valve (209) and the low-temperature-level evaporator (210) back to an air inlet of the two-stage compressor (203), and the intermediate heat exchanger (118) is configured to enable the high-temperature-level refrigerant to cool the low-temperature-level refrigerant.
5. The cascade refrigeration system of claim 4, wherein the second refrigeration circuit (20) further comprises an oil separator (207), the oil separator (207) being connected in series between the precooler (205) and the intermediate heat exchanger (118), the oil separator (207) being configured to convey oil in the low-temperature-stage refrigerant back to the two-stage compressor (203).
6. The cascade refrigeration system of claim 4, wherein the second refrigeration circuit (20) further comprises a second discharge temperature sensor (204), a fourth solenoid valve (211) and a second capillary tube (212), the fourth solenoid valve (211) and the second capillary tube (212) being connected in series between the outlet of the second dry filter (208) and the outlet of the low-temperature-stage evaporator (210), the second discharge temperature sensor (204) being configured to detect a temperature of the discharge port of the secondary compressor (203), the second discharge temperature sensor (204) detecting that the discharge port temperature of the secondary compressor (203) is higher than a preset discharge temperature of the secondary compressor (203), the fourth solenoid valve (211) being opened such that the low-temperature-stage refrigerant after flowing through the second capillary tube (212) is mixed with the low-temperature-stage refrigerant at the outlet of the low-temperature-stage evaporator (210) and sucked by the secondary compressor (203).
7. The cascade refrigeration system of claim 4, characterized in that the second refrigeration circuit (20) further comprises a second pressure protection assembly configured to bring the second refrigeration circuit (20) pressure to a preset range.
8. Environmental test chamber comprising a cascade refrigeration system according to any of claims 1-7.
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| CN202410201381.3A CN118031447A (en) | 2022-09-14 | 2022-09-14 | Cascade refrigeration system and environmental test box |
| CN202211116304.5A CN115406129B (en) | 2022-09-14 | 2022-09-14 | Cascade refrigeration system and environmental test box |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103499156A (en) * | 2013-09-24 | 2014-01-08 | 广州赛宝仪器设备有限公司 | High-and-low-temperature environmental testing refrigerating system, high-and-low-temperature environmental testing box and control method |
| CN204943954U (en) * | 2015-06-23 | 2016-01-06 | 广州东之旭试验设备有限公司 | Low energy consumption refrigeration system |
| CN110806034A (en) * | 2019-12-11 | 2020-02-18 | 郑州长城科工贸有限公司 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
| CN211146951U (en) * | 2019-12-02 | 2020-07-31 | 郑州长城科工贸有限公司 | Cascade refrigeration system |
| CN211372811U (en) * | 2019-12-17 | 2020-08-28 | 广州斯派克环境仪器有限公司 | High-low temperature test device |
-
2022
- 2022-09-14 CN CN202211116304.5A patent/CN115406129B/en active Active
- 2022-09-14 CN CN202410201381.3A patent/CN118031447A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103499156A (en) * | 2013-09-24 | 2014-01-08 | 广州赛宝仪器设备有限公司 | High-and-low-temperature environmental testing refrigerating system, high-and-low-temperature environmental testing box and control method |
| CN204943954U (en) * | 2015-06-23 | 2016-01-06 | 广州东之旭试验设备有限公司 | Low energy consumption refrigeration system |
| CN211146951U (en) * | 2019-12-02 | 2020-07-31 | 郑州长城科工贸有限公司 | Cascade refrigeration system |
| CN110806034A (en) * | 2019-12-11 | 2020-02-18 | 郑州长城科工贸有限公司 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
| CN211372811U (en) * | 2019-12-17 | 2020-08-28 | 广州斯派克环境仪器有限公司 | High-low temperature test device |
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| CN118031447A (en) | 2024-05-14 |
| CN115406129A (en) | 2022-11-29 |
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