CN110806034A - -80 ℃ -200 ℃ temperature zone cascade refrigeration system - Google Patents
-80 ℃ -200 ℃ temperature zone cascade refrigeration system Download PDFInfo
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- CN110806034A CN110806034A CN201911266644.4A CN201911266644A CN110806034A CN 110806034 A CN110806034 A CN 110806034A CN 201911266644 A CN201911266644 A CN 201911266644A CN 110806034 A CN110806034 A CN 110806034A
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- 238000005057 refrigeration Methods 0.000 title claims abstract description 82
- 238000005507 spraying Methods 0.000 claims abstract description 41
- 239000007788 liquid Substances 0.000 claims abstract description 40
- 238000009833 condensation Methods 0.000 claims abstract description 24
- 230000005494 condensation Effects 0.000 claims abstract description 24
- 238000001035 drying Methods 0.000 claims abstract description 7
- 239000003507 refrigerant Substances 0.000 claims description 39
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 claims description 32
- 230000008020 evaporation Effects 0.000 claims description 16
- 238000001704 evaporation Methods 0.000 claims description 16
- 230000006835 compression Effects 0.000 claims description 14
- 238000007906 compression Methods 0.000 claims description 14
- LVGUZGTVOIAKKC-UHFFFAOYSA-N 1,1,1,2-tetrafluoroethane Chemical compound FCC(F)(F)F LVGUZGTVOIAKKC-UHFFFAOYSA-N 0.000 claims description 6
- UJPMYEOUBPIPHQ-UHFFFAOYSA-N 1,1,1-trifluoroethane Chemical compound CC(F)(F)F UJPMYEOUBPIPHQ-UHFFFAOYSA-N 0.000 claims description 6
- GTLACDSXYULKMZ-UHFFFAOYSA-N pentafluoroethane Chemical compound FC(F)C(F)(F)F GTLACDSXYULKMZ-UHFFFAOYSA-N 0.000 claims description 6
- 230000008676 import Effects 0.000 claims description 4
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- 230000006698 induction Effects 0.000 claims description 2
- 238000000034 method Methods 0.000 claims description 2
- 239000003921 oil Substances 0.000 abstract description 38
- 239000010721 machine oil Substances 0.000 abstract description 15
- 238000003763 carbonization Methods 0.000 abstract description 5
- 239000003595 mist Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 3
- 238000010793 Steam injection (oil industry) Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000011010 flushing procedure Methods 0.000 description 2
- 230000008014 freezing Effects 0.000 description 2
- 238000007710 freezing Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000001105 regulatory effect Effects 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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- 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
-
- 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
-
- 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
- F25B2500/00—Problems to be solved
- F25B2500/29—High ambient temperatures
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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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
Abstract
The invention discloses a cascade refrigeration system of a temperature region of-80-200 ℃, which comprises a high-temperature refrigeration unit and a low-temperature refrigeration unit; the low-temperature stage refrigeration unit consists of a rear-stage compressor, a precooler, a first oil separator, a second oil separator, a condensation evaporator, a subcooler, a heat regenerator, an evaporator, an expansion container, a flow limiting pipe, a rear-stage liquid spraying throttle pipe, an unloading valve, a rear-stage throttling electronic expansion valve and a rear-stage electromagnetic liquid spraying valve, wherein the opening degree of the rear-stage throttling electronic expansion valve and the rear-stage electromagnetic liquid spraying valve are controlled by a controller; the high-temperature stage refrigeration unit consists of a preceding stage compressor, a preceding stage condenser, a drying filter, a preceding stage liquid spraying throttling pipe, a preceding stage throttling electronic expansion valve and a preceding stage electromagnetic liquid spraying valve. The invention effectively avoids the problems of overhigh suction pressure, overhigh exhaust temperature, carbonization of refrigerating machine oil, overload or damage of a compressor and the like of the cascade refrigeration system when the cascade refrigeration system works in a temperature region of normal temperature to high temperature of 200 ℃.
Description
Technical Field
The invention relates to a cascade refrigeration system, in particular to a cascade refrigeration system with a temperature range of-80-200 ℃.
Background
At present, the temperature range of the cascade refrigeration system capable of normally working is-80 ℃ to normal temperature region, if the cascade refrigeration system works in the temperature region of normal temperature to high temperature of 200 ℃, the problems of overhigh suction pressure, overhigh exhaust temperature, carbonization of refrigerating machine oil, overload or damage of a compressor and the like of the refrigeration system are easily caused.
Disclosure of Invention
The invention aims to provide a cascade refrigeration system with a temperature range of-80 ℃ to 200 ℃.
In order to achieve the purpose, the invention adopts the following technical scheme:
the cascade refrigeration system of the temperature region of-80 ℃ to 200 ℃ comprises a high-temperature refrigeration unit and a low-temperature refrigeration unit; the high-temperature stage refrigeration unit is filled with a mixed pentafluoroethane/trifluoroethane/tetrafluoroethane refrigerant (R404A), and the low-temperature stage refrigeration unit is filled with a trifluoromethane refrigerant.
The low-temperature stage refrigeration unit consists of a rear-stage compressor, a precooler, a first oil separator, a second oil separator, a condensation evaporator, a subcooler, a heat regenerator, an evaporator, an expansion container, a flow limiting pipe, a rear-stage liquid spraying throttle pipe, an unloading valve, a rear-stage throttling electronic expansion valve and a rear-stage electromagnetic liquid spraying valve, wherein the opening degree of the rear-stage throttling electronic expansion valve and the rear-stage electromagnetic liquid spraying valve are controlled by a controller; one path of the exhaust port of the rear-stage compressor is communicated with the inlet of a refrigerant channel of the precooler, the outlet of the refrigerant channel of the precooler is communicated with the inlet of the first oil separator, the outlet of the first oil separator is communicated with the inlet of the second oil separator, the outlet of the second oil separator is communicated with the inlet of a condensing channel of the condensing evaporator, the outlet of the condensing channel of the condensing evaporator is communicated with the inlet of a tube pass of the subcooler, one path of the outlet of the tube pass of the subcooler is communicated with the inlet of the rear-stage throttling electronic expansion valve, the outlet of the rear-stage throttling electronic expansion valve is communicated with the inlet of the tube pass of the reheater, the outlet of the tube pass of the reheater is communicated with the inlet of the evaporator, the outlet of the evaporator is communicated with the inlet of a shell pass of the reheater, and the outlet of the shell pass of; the other path of the exhaust port of the rear-stage compressor is communicated with an inlet of an unloading valve, an outlet of the unloading valve is communicated with an inlet of an expansion container, an outlet of the expansion container is communicated with an inlet of a flow-limiting pipe, and an outlet of the flow-limiting pipe is communicated with an air suction port of the rear-stage compressor to form a pressure relief loop; the other path of the pipe pass outlet of the subcooler is communicated with the inlet of a rear-stage electromagnetic liquid spraying valve, the outlet of the rear-stage electromagnetic liquid spraying valve is communicated with the inlet of a rear-stage liquid spraying throttling pipe, the outlet of the rear-stage liquid spraying throttling pipe is communicated with the shell pass inlet of the subcooler, and the shell pass outlet of the subcooler is communicated with the air suction port of the compression cavity of the rear-stage compressor to form a low-temperature stage refrigeration unit wet vapor injection loop.
The low-temperature stage refrigeration unit main loop adopts a series combination of two-stage oil separators, and an oil outlet of the first oil separator and an oil outlet of the second oil separator are connected in parallel and then communicated with an oil return port of the rear-stage compressor to form an oil return loop. The two-stage oil separator is combined in series to reduce the oil quantity of the refrigerating machine brought into other parts of the system by the refrigerant; when the working temperature of the low-temperature stage refrigeration unit is-60 ℃ or below, the flow of the refrigerating machine oil entering the evaporator is the same as that of the refrigerating machine oil brought out of the evaporator by flushing the trifluoromethane, so that dynamic balance is realized, and the freezing of the refrigerating machine oil is avoided. When the working temperature of the low-temperature refrigeration unit is 200 ℃, the refrigerating machine oil brought into the condensation evaporator cannot form a thick oil film; in a condensation evaporator, the trifluoromethane carries oil mist to form mist flow, and the mist flow is condensed to form oil-containing trifluoromethane solution; the layering phenomenon of the trifluoromethane and the refrigerating machine oil in the condensing evaporator is avoided.
When the exhaust pressure of the rear-stage compressor is higher than 2.5Mpa, the pressure is released into the expansion container immediately, and a phi 2mm flow-limiting pipe is designed at the outlet of the expansion container, so that the refrigerant in the expansion container slowly enters the main loop of the low-temperature stage refrigeration unit.
The low-temperature stage refrigeration unit wet vapor is injected into the loop, the opening duration of the rear-stage electromagnetic liquid spraying valve is controlled, the flow of the refrigerant flowing through the rear-stage throttling pipe and entering the compression cavity of the rear-stage compressor is regulated, the refrigerant entering the compression cavity of the rear-stage compressor is mixed with the superheated vapor sucked by the compression cavity, and the exhaust temperature of the rear-stage compressor is reduced; when the low-temperature stage refrigeration unit works at any temperature of a temperature range of-80 ℃ to 200 ℃, the exhaust temperature of the rear stage compressor is not more than 110 ℃, and the carbonization of the refrigerating machine oil is avoided.
The low-temperature stage refrigeration unit is provided with a heat regenerator, refrigerant flowing through a rear-stage throttling electronic expansion valve enters a tube pass of the heat regenerator after throttling and pressure reduction, and exchanges heat with superheated refrigerant flowing out of an evaporator and entering the heat regenerator, so that the temperature of the superheated refrigerant returning to a suction port of a rear-stage compressor is reduced when the refrigeration system works in a temperature range from normal temperature to high temperature of 200 ℃.
The shell-tube pass of the heat regenerator is arranged to be close to the cross flow of the countercurrent, the tube pass is a low-rib spiral tube, and the heat exchange effect is increased by more than 10 percent; the design of the shell-side reverse-spiral disturbance flow blocking pipe realizes that the shell side is not short-circuited, and the heat exchange effect is improved.
The high-temperature stage refrigeration unit consists of a preceding stage compressor, a preceding stage condenser, a drying filter, a preceding stage liquid spraying throttling pipe, a preceding stage throttling electronic expansion valve and a preceding stage electromagnetic liquid spraying valve. The exhaust port of the front stage compressor is communicated with the inlet of a refrigerant channel of the front stage condenser, the outlet of the refrigerant channel of the front stage condenser is communicated with the inlet of a dry filter, one path of the outlet of the dry filter is communicated with the inlet of a front stage throttle electronic expansion valve, the outlet of the front stage throttle electronic expansion valve is communicated with the inlet of an evaporation channel of a condensation evaporator, and the outlet of the evaporation channel of the condensation evaporator is communicated with the air suction port of the front stage compressor to form a main loop of the high-temperature stage refrigeration unit. The other way of drier-filter export communicates with the import of preceding stage electromagnetism hydrojet valve, the export and the import of preceding stage hydrojet throttle pipe intercommunication of preceding stage electromagnetism hydrojet valve, preceding stage hydrojet throttle pipe export and preceding stage compressor compression chamber induction port intercommunication form high temperature level refrigeration unit wet steam and pour into the return circuit into.
The high-temperature refrigeration unit realizes the evaporation temperature of minus 45 ℃ to 0 ℃ in an evaporation channel of the condensation evaporator, and effectively condenses the refrigerant trifluoromethane in the condensation channel of the condensation evaporator. The wide temperature range change of the evaporation temperature is to adapt to the wide change of the condensation temperature caused by the wide change of the evaporation temperature of the low-temperature refrigeration unit.
The wet steam injection loop of the high-temperature refrigeration unit controls the opening time of the front-stage electromagnetic liquid spraying valve, regulates and controls the flow of a pentafluoroethane/trifluoroethane/tetrafluoroethane mixed refrigerant flowing through the front-stage electromagnetic liquid spraying valve and the front-stage liquid spraying throttling pipe, injects the wet steam into a compression cavity of the front-stage compressor, and reduces the exhaust temperature of the front-stage compressor, so that the high-temperature refrigeration unit and the low-temperature refrigeration unit realize self-adaptive coupling.
The evaporation of mixed refrigerant pentafluoroethane/trifluoroethane/tetrafluoroethane in the high-temperature refrigeration unit is used for condensing refrigerant trifluoromethane in the low-temperature refrigeration unit, and the high-temperature refrigeration unit and the low-temperature refrigeration unit are connected through a condensing evaporator. Thus, the condensing evaporator is both an evaporator of the high temperature stage refrigeration unit and a condenser of the low temperature stage refrigeration unit.
The invention effectively avoids the problems of overhigh suction pressure, overhigh exhaust temperature, carbonization of refrigerating machine oil, overload or damage of a compressor and the like of the cascade refrigeration system when the cascade refrigeration system works in a temperature region of normal temperature to high temperature of 200 ℃.
Drawings
FIG. 1 is a schematic diagram of a cascade refrigeration system with a temperature range of-80 deg.C to 200 deg.C.
Detailed Description
The following describes embodiments of the present invention in detail with reference to the drawings, which are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are provided, but the scope of the present invention is not limited to the following embodiments.
As shown in figure 1, the-80-200 ℃ temperature zone cascade refrigeration system comprises a low-temperature refrigeration unit 1 and a high-temperature refrigeration unit 2.
The low-temperature stage refrigeration unit 1 is composed of a rear-stage compressor 1.1, a precooler 1.2, a first oil separator 1.3, a second oil separator 1.4, a condensation evaporator 1.5, a subcooler 1.6, a heat regenerator 1.7, an evaporator 1.8, a rear-stage throttling electronic expansion valve 1.9 with the opening controlled by a controller, a rear-stage electromagnetic liquid spraying valve 1.10, a rear-stage liquid spraying throttling pipe 1.11, an expansion container 1.12, a flow limiting pipe 1.13 and an unloading valve 1.14. One path of an exhaust port of the rear-stage compressor 1.1 is communicated with an inlet of a refrigerant channel of the precooler 1.2, an outlet of the refrigerant channel of the precooler 1.2 is communicated with an inlet of the first oil separator 1.3, an outlet of the first oil separator 1.3 is communicated with an inlet of the second oil separator 1.4, an outlet of the second oil separator 1.4 is communicated with an inlet of a condensing channel of the condensing evaporator 1.5, an outlet of the condensing channel of the condensing evaporator 1.5 is communicated with an inlet of a tube pass of the subcooler 1.6, one path of an outlet of the tube pass of the subcooler 1.6 is communicated with an inlet of a rear-stage throttling electronic expansion valve 1.9, an outlet of the rear-stage throttling electronic expansion valve 1.9 is communicated with an inlet of a tube pass of the reheater 1.7, an outlet of the tube pass of the reheater 1.7 is communicated with an inlet of the evaporator 1.8, an outlet of the shell pass of the evaporator 1.8 is communicated with an inlet of the reheater 1.7, and an outlet of the. An oil outlet of the first oil separator 1.3 and an oil outlet of the second oil separator 1.4 are connected in parallel and then communicated with an oil return port of the rear-stage compressor 1.1 to form an oil return loop of the low-temperature-stage refrigeration unit 1. The other path of the exhaust port of the rear-stage compressor 1.1 is communicated with an inlet of an unloading valve 1.14, an outlet of the unloading valve 1.14 is communicated with an inlet of an expansion container 1.12, an outlet of the expansion container 1.12 is communicated with an inlet of a flow limiting pipe 1.13, and an outlet of the flow limiting pipe 1.13 is communicated with an air suction port of the rear-stage compressor 1.1 to form a pressure release loop of the low-temperature-stage refrigeration unit 1. The other path of the pipe pass outlet of the subcooler 1.6 is communicated with the inlet of a rear-stage electromagnetic liquid spraying valve 1.10, the outlet of the rear-stage electromagnetic liquid spraying valve 1.10 is communicated with the inlet of a rear-stage liquid spraying throttle pipe 1.11, the outlet of the rear-stage liquid spraying throttle pipe 1.11 is communicated with the shell pass inlet of the subcooler 1.6, and the shell pass outlet of the subcooler 1.6 is communicated with the air suction port of the compression cavity of the rear-stage compressor 1.1 to form a wet vapor injection loop of the low-temperature-stage refrigeration unit 1.
The high-temperature stage refrigeration unit 2 consists of a preceding stage compressor 2.1, a preceding stage condenser 2.2, a drying filter 2.3, a preceding stage throttling electronic expansion valve 2.4, a preceding stage electromagnetic liquid spraying valve 2.5 and a preceding stage liquid spraying throttling pipe 2.6. An exhaust port of a front stage compressor 2.1 is communicated with an inlet of a refrigerant channel of the front stage condenser 2.2, an outlet of the refrigerant channel of the front stage condenser 2.2 is communicated with an inlet of a drying filter 2.3, one path of an outlet of the drying filter 2.3 is communicated with an inlet of a front stage throttling electronic expansion valve 2.4, an outlet of the front stage throttling electronic expansion valve 2.4 is communicated with an inlet of an evaporation channel of a condensation evaporator 1.5, and an outlet of the evaporation channel of the condensation evaporator 1.5 is communicated with an air suction port of the front stage compressor 2.1 to form a main loop of the. The other path of the outlet of the drying filter 2.3 is communicated with the inlet of a preceding stage electromagnetic liquid spraying valve 2.5, the outlet of the preceding stage electromagnetic liquid spraying valve 2.5 is communicated with the inlet of a preceding stage liquid spraying throttling pipe 2.6, the outlet of the preceding stage liquid spraying throttling pipe 2.6 is communicated with the air suction port of a compression cavity of a preceding stage compressor 2.1, and a wet steam injection loop of the high-temperature stage refrigeration unit 2 is formed.
The mixed refrigerant pentafluoroethane/trifluoroethane/tetrafluoroethane (R404A) is filled in the high-temperature refrigeration unit 2, and the refrigerant trifluoromethane is filled in the low-temperature refrigeration unit 1.
In the high-temperature-stage refrigeration unit 2, evaporation of mixed refrigerant pentafluoroethane/trifluoroethane/tetrafluoroethane is used for condensing refrigerant trifluoromethane in the low-temperature-stage refrigeration unit 1, and the high-temperature-stage refrigeration unit 2 and the low-temperature-stage refrigeration unit 1 are connected through a condensation evaporator 1.5. The condenser evaporator 1.5 is thus both an evaporator of the high-temperature stage refrigeration unit 2 and a condenser of the low-temperature stage refrigeration unit 1.
According to the invention, the first oil separator 1.3 and the second oil separator 1.4 are combined in series, so that the amount of the refrigerator oil brought into other parts of the system by the trifluoromethane is reduced. When the working temperature of the low-temperature stage refrigerating unit 1 is-60 ℃ or below, the flow of the refrigerating machine oil entering the evaporator 1.8 is the same as that of the refrigerating machine oil carried out of the evaporator 1.8 by flushing trifluoromethane, so that dynamic balance is realized, and the freezing of the refrigerating machine oil is avoided. When the working temperature of the low-temperature stage refrigeration unit 1 is 200 ℃, the refrigerating machine oil brought into the condensation evaporator 1.5 cannot form a thick oil film; in the condensation evaporator 1.5, the trifluoromethane carries the oil mist to form mist flow, and the mist flow is condensed to form oil-containing trifluoromethane solution, so that the layering phenomenon of the trifluoromethane and the refrigerating machine oil in the condensation evaporator 1.5 is avoided.
According to the invention, the phi 2mm flow-limiting pipe 1.13 in the pressure relief loop of the low-temperature stage refrigeration unit 1 enables the refrigerant in the expansion container 1.12 to slowly enter the main loop of the low-temperature stage refrigeration unit 1, so that the system is more stable.
The invention controls the flow of the refrigerant which flows through the rear-stage throttle pipe 1.11 and enters the compression cavity of the rear-stage compressor 1.1 by controlling the opening time of the rear-stage electromagnetic liquid-spraying valve 1.10, so that the refrigerant entering the compression cavity of the rear-stage compressor 1.1 is mixed with the superheated steam sucked by the compression cavity, the exhaust temperature of the rear-stage compressor 1.1 is reduced, and when the low-temperature stage refrigeration unit 1 works at any temperature of a temperature region of-80 ℃ to 200 ℃, the exhaust temperature of the rear-stage compressor 1.1 is not more than 110 ℃, and the carbonization of the refrigerating machine oil is avoided.
In the invention, the refrigerant flowing through the rear-stage throttle electronic expansion valve 1.9 enters the tube pass of the heat regenerator 1.7 after throttling and pressure reduction, and exchanges heat with the superheated steam flowing out of the evaporator 1.8 and entering the heat regenerator 1.7, so that the temperature of the superheated steam at the air suction port of the rear-stage compressor 1.1 when the compressor works in a temperature range of normal temperature to high temperature of 200 ℃ is reduced, and the exhaust temperature of the rear-stage compressor 1.1 is reduced.
The shell-tube side of the heat regenerator 1.7 is arranged to be close to the cross flow of the counter flow, the tube side is a low-rib spiral tube, and the heat exchange effect is increased by more than 10 percent; the design of the shell-side reverse-spiral disturbance flow blocking pipe realizes that the shell side is not short-circuited, and the heat exchange effect is improved.
The high-temperature-stage refrigeration unit 2 can realize the evaporation temperature of minus 45 ℃ to 0 ℃ in the evaporation channel of the condensation evaporator 1.5, and effectively condenses the refrigerant trifluoromethane in the condensation channel of the condensation evaporator 1.5.
The wide temperature range change of the evaporation temperature is to adapt to the wide change of the condensation temperature caused by the wide change of the evaporation temperature of the low-temperature refrigeration unit 1.
According to the invention, the injection amount of refrigerant wet vapor in a compression cavity of the preceding stage compressor 2.1 is adjusted by controlling the opening time of the preceding stage electromagnetic liquid spraying valve 2.5, and the exhaust temperature of the preceding stage compressor 2.1 is reduced, so that the high-temperature stage refrigeration unit 2 and the low-temperature stage refrigeration unit 1 realize self-adaptive coupling.
Claims (1)
1. A-80 deg.C-200 deg.C temperature range cascade refrigeration system comprises a high-temperature refrigeration unit and a low-temperature refrigeration unit; the high-temperature-stage refrigeration unit is filled with a pentafluoroethane/trifluoroethane/tetrafluoroethane mixed refrigerant, and the low-temperature-stage refrigeration unit is filled with a trifluoromethane refrigerant; the method is characterized in that:
the low-temperature stage refrigeration unit consists of a rear-stage compressor, a precooler, a first oil separator, a second oil separator, a condensation evaporator, a subcooler, a heat regenerator, an evaporator, an expansion container, a flow limiting pipe, a rear-stage liquid spraying throttle pipe, an unloading valve, a rear-stage throttling electronic expansion valve and a rear-stage electromagnetic liquid spraying valve, wherein the opening degree of the rear-stage throttling electronic expansion valve and the rear-stage electromagnetic liquid spraying valve are controlled by a controller; one path of the exhaust port of the rear-stage compressor is communicated with the inlet of a refrigerant channel of the precooler, the outlet of the refrigerant channel of the precooler is communicated with the inlet of the first oil separator, the outlet of the first oil separator is communicated with the inlet of the second oil separator, the outlet of the second oil separator is communicated with the inlet of a condensing channel of the condensing evaporator, the outlet of the condensing channel of the condensing evaporator is communicated with the inlet of a tube pass of the subcooler, one path of the outlet of the tube pass of the subcooler is communicated with the inlet of the rear-stage throttling electronic expansion valve, the outlet of the rear-stage throttling electronic expansion valve is communicated with the inlet of the tube pass of the reheater, the outlet of the tube pass of the reheater is communicated with the inlet of the evaporator, the outlet of the evaporator is communicated with the inlet of a shell pass of the reheater, and the outlet of the shell pass of; the other path of the exhaust port of the rear-stage compressor is communicated with an inlet of an unloading valve, an outlet of the unloading valve is communicated with an inlet of an expansion container, an outlet of the expansion container is communicated with an inlet of a flow-limiting pipe, and an outlet of the flow-limiting pipe is communicated with an air suction port of the rear-stage compressor to form a pressure relief loop; the other path of the pipe pass outlet of the subcooler is communicated with the inlet of a rear-stage electromagnetic liquid spraying valve, the outlet of the rear-stage electromagnetic liquid spraying valve is communicated with the inlet of a rear-stage liquid spraying throttling pipe, the outlet of the rear-stage liquid spraying throttling pipe is communicated with the shell pass inlet of the subcooler, and the shell pass outlet of the subcooler is communicated with the air suction port of a compression cavity of a rear-stage compressor to form a low-temperature stage refrigeration unit wet vapor injection loop;
the high-temperature stage refrigeration unit consists of a preceding stage compressor, a preceding stage condenser, a drying filter, a preceding stage liquid spraying throttling pipe, a preceding stage throttling electronic expansion valve and a preceding stage electromagnetic liquid spraying valve; the exhaust port of the preceding stage compressor is communicated with the inlet of a refrigerant channel of the preceding stage condenser, the outlet of the refrigerant channel of the preceding stage condenser is communicated with the inlet of a dry filter, one path of the outlet of the dry filter is communicated with the inlet of a preceding stage throttling electronic expansion valve, the outlet of the preceding stage throttling electronic expansion valve is communicated with the inlet of an evaporation channel of the condensation evaporator, the outlet of the evaporation channel of the condensation evaporator is communicated with the air suction port of the preceding stage compressor, and a main loop of the high-temperature stage refrigeration unit is formed; the other way of drier-filter export communicates with the import of preceding stage electromagnetism hydrojet valve, the export and the import of preceding stage hydrojet throttle pipe intercommunication of preceding stage electromagnetism hydrojet valve, preceding stage hydrojet throttle pipe export and preceding stage compressor compression chamber induction port intercommunication form high temperature level refrigeration unit wet steam and pour into the return circuit into.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911266644.4A CN110806034A (en) | 2019-12-11 | 2019-12-11 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911266644.4A CN110806034A (en) | 2019-12-11 | 2019-12-11 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115406129A (en) * | 2022-09-14 | 2022-11-29 | 江苏拓米洛环境试验设备有限公司 | Overlapping refrigerating system and environmental test chamber |
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| CN102435004A (en) * | 2011-12-19 | 2012-05-02 | 无锡同方人工环境有限公司 | Multifunctional high-temperature water outlet air conditioner heat pump unit |
| CN206103946U (en) * | 2016-10-25 | 2017-04-19 | 广州斯派克环境仪器有限公司 | High low temperature test device that refrigerating system operating mode is more stable |
| CN211146954U (en) * | 2019-12-11 | 2020-07-31 | 郑州长城科工贸有限公司 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
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| JPH0682107A (en) * | 1992-07-15 | 1994-03-22 | Daikin Ind Ltd | Dual refrigerating machine |
| CN102435004A (en) * | 2011-12-19 | 2012-05-02 | 无锡同方人工环境有限公司 | Multifunctional high-temperature water outlet air conditioner heat pump unit |
| CN206103946U (en) * | 2016-10-25 | 2017-04-19 | 广州斯派克环境仪器有限公司 | High low temperature test device that refrigerating system operating mode is more stable |
| CN211146954U (en) * | 2019-12-11 | 2020-07-31 | 郑州长城科工贸有限公司 | -80 ℃ -200 ℃ temperature zone cascade refrigeration system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115406129A (en) * | 2022-09-14 | 2022-11-29 | 江苏拓米洛环境试验设备有限公司 | Overlapping refrigerating system and environmental test chamber |
| CN115406129B (en) * | 2022-09-14 | 2024-03-19 | 江苏拓米洛高端装备股份有限公司 | Cascade refrigeration system and environmental test box |
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