CN213811205U - Improved large-span low-temperature refrigerating system for test box - Google Patents

Abstract

The utility model discloses an improved large-span low-temperature refrigerating system for a test box, which comprises a high-temperature-level unit, a low-temperature-level unit and a cold-carrying unit which are superposed and refrigerated, and cooling water circulation integration which is communicated with the high-temperature-level unit, the low-temperature-level unit and the cold-carrying unit; the high-temperature-stage unit and the low-temperature stageBe provided with the condensation evaporimeter between the unit, carry and be provided with medium temperature level evaporimeter between cold unit and the high temperature level unit, carry and be provided with the D evaporimeter between cold unit and the low temperature level unit, the low temperature level unit includes M parallelly connected D compressors, M the platform the end of breathing in of D compressor all communicates in D manifold of breathing in, and the exhaust end all communicates in D manifold of breathing in, M preceding M₁Stage and rear M₂A D suction manifold and a D suction manifold between the D compressors are respectively provided with a through switch valve and a shunt three-way switch valve, wherein M is M₁+M₂And M is₁≤M₂And the angle valve side of the flow dividing three-way switch valve is communicated with the D air suction manifold. It reduces the pressure ratio, improves the operation efficiency and the safety, and is beneficial to obtaining lower temperature.

Description

Improved large-span low-temperature refrigerating system for test box

Technical Field

The utility model relates to a special type refrigeration technology field, concretely relates to large-span low temperature refrigerating system is used to modified proof box.

Background

When a cold space is used for refrigeration, along with the wide range change of temperature, contradiction exists between the cold demand load and the refrigeration capacity of the refrigerating unit, the higher the temperature is, the smaller the space cold demand is, and the larger the refrigeration capacity of the specific refrigerating unit is; especially, a large-mass load experiment article and a large-mass cold (heat) storage material are often arranged in a plurality of large-volume low-temperature experiment spaces, the temperature reduction process has time limitation or speed requirement, so that relatively larger refrigerating output is needed in the temperature reduction stage, the cold storage load is basically reduced to zero in the temperature maintaining stage, and the refrigerating load requirement is reduced to be very small. In all the refrigeration occasions, the requirement that the refrigerating unit has good unloading capacity is mainly realized by connecting a plurality of units in parallel or frequency conversion units, under the current situation that the frequency conversion units are not generally applied in the application field of special refrigeration at present, if the number of compressors is too small, the load shedding capacity of the unit in the maintenance stage is weak, the temperature control precision is difficult to realize, and the energy consumption is obvious by adopting a heating balance mode for temperature control, so that the defects are more serious under the requirement of a large temperature difference cooling environment.

For the large temperature difference cooling refrigeration in the common refrigeration, no matter single-stage refrigeration or overlapping refrigeration, the compression ratio is larger when the compressor operates along with the lower box temperature, the efficiency of the compressor is reduced, and particularly when the single-unit pressure ratio exceeds more than 6, the efficiency is often generated in the operation of an actual refrigeration system. Therefore, the refrigeration system needs to increase the compression stages more advantageously, such as configuring the refrigeration system as two-stage compression cascade or three-stage cascade, but such fixed multi-stage refrigeration configuration can affect the refrigeration efficiency when the temperature of other temperature sections is reduced in the whole process of box temperature change.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is to provide an improved large-span low-temperature refrigeration system for a test chamber, which reduces the pressure ratio through reasonable structural design, improves the operation efficiency and safety, and is beneficial to obtaining lower temperature; the natural cooling capacity is fully utilized in the cooling process, the high evaporation temperature of the refrigerating unit is always ensured, and the refrigerating efficiency of the unit is maintained at any time.

In order to solve the technical problem, the utility model provides an improved large-span low-temperature refrigeration system for test box, which comprises a high-temperature-level unit, a low-temperature-level unit, a cold-carrying unit which are overlapped and refrigerated, and a cooling water circulation integration which is communicated with the high-temperature-level unit, the low-temperature-level unit and the cold-carrying unit; be provided with the condensation evaporimeter between high-temperature level unit and the low-temperature level unit, be provided with the medium temperature level evaporimeter between year cold machine group and the high-temperature level unit, be provided with the D evaporimeter between year cold machine group and the low-temperature level unit, the low-temperature level unit includes M parallelly connected D compressors, M platform the end of breathing in of D compressor all communicates in D collector of breathing in, and the exhaust end all communicates in D collector of breathing in, M preceding M₁Stage and rear M₂A D suction manifold and a D suction manifold between the D compressors are respectively provided with a through switch valve and a shunt three-way switch valve, wherein M is M₁+M₂And M is₁≤M₂And the angle valve side of the flow dividing three-way switch valve is communicated with the D air suction manifold.

In a preferred embodiment of the present invention, the D compressor is further provided with a D oil return pipe and a D liquid spray pipe, the D oil return pipe is provided with a solenoid valve, each D oil return pipe is connected out from a D oil return manifold and communicated to a D oil separator, the D oil separator is communicated with a D oil cooler, and an oil thermostatic valve is arranged on an oil return pipeline connected to the D oil cooler; and liquid spraying pipeline electromagnetic valves are arranged on the D liquid spraying pipes of the D compressor, and each D liquid spraying pipe is connected with a liquid inlet pipe of a supercooling side pipeline of the D economizer.

In a preferred embodiment of the present invention, the suction manifold is connected to the D evaporator; and an evaporation side gas return pipe of the D economizer is connected to a D gas suction header.

In a preferred embodiment of the present invention, the D oil separator further comprises a working medium outlet pipe connected to a working medium inlet of the D precooler, a working medium outlet of the D precooler is connected to a condensation side inlet of the condensation evaporator, the condensation side outlet of the condensation evaporator is divided into two pipelines after passing through the electromagnetic valve, and respectively connected to two side orifices of the evaporation side and the supercooling side of the D economizer, wherein the pipeline of the evaporation side is provided with the electromagnetic valve and the temperature control expansion valve, and the outlet of the D economizer is connected to the D suction manifold through a return pipe of the D economizer; and the supercooling side inlet pipeline of the D economizer is respectively connected with three pipelines, and the three pipelines are respectively connected with the liquid spraying ports of the D compressors through the D liquid spraying pipes where the liquid spraying pipe electromagnetic valves are positioned.

In a preferred embodiment of the present invention, the number of the D compressors is 2 to 5.

The utility model discloses a preferred embodiment, further include the motorised valve that straight-through switch valve and reposition of redundant personnel three way switch valve are associated electric action, work as when straight-through switch valve is closed, reposition of redundant personnel three way switch valve simultaneously the angle leads to, the high temperature stage unit that M platform parallelly connected D compressor constitutes switches into the double stage compressor unit, wherein M is parallelly connected D compressor and is constituted₂The platform parallel D compressors form a low-pressure stage unit of the two-stage unit, M₁The platform parallel connection D compressor forms a high-pressure stage unit of the double-stage unit.

In a preferred embodiment of the present invention, the high temperature stage unit further includes M G compressors, wherein the exhaust ends of the M G compressors are all connected to a G exhaust manifold, the suction ends are all connected to a G suction manifold, the oil return ends are connected to a G oil return manifold after passing through a solenoid valve, the G oil return manifold is connected to a G oil separator, the G oil separator is connected to a G oil cooler, and an oil return line connecting the G oil cooler is provided with an oil thermostatic valve; the gas return pipes of the G economizers and the G compressor are provided with electromagnetic valves, the G gas suction manifold is connected with the outlet of the G gas-liquid separator through a G gas-component gas return main pipe, and the inlet of the G gas-liquid separator is connected with the evaporation side outlet of the condensation evaporator and the evaporation side outlet of the medium-temperature grade evaporator in parallel through the G gas return main pipe; and the G exhaust manifold is connected to the inlet of the G oil separator through a G exhaust manifold.

In a preferred embodiment of the present invention, the working medium outlet pipe of the G oil separator is connected to the working medium side inlet of the G condenser, the working medium side outlet of the G condenser is divided into two pipelines after passing through the electromagnetic valve, and the two pipelines are respectively connected to the orifices on both sides of the evaporation side and the supercooling side of the G economizer, wherein the pipeline on the evaporation side is provided with the electromagnetic valve and the throttle valve, and the outlet of the G economizer is connected to the economizer interface of the G compressor through the return pipe of the G economizer; the inlet main pipe at the supercooling side enters the G economizer, the circulating working medium is supercooled in the G economizer and then divided into two pipelines which are respectively connected with the condensing evaporator and the medium temperature grade evaporator through the electromagnetic valve and the throttle valve.

In a preferred embodiment of the present invention, the low-temperature stage unit further comprises a low-pressure expansion tank, and a main pipe of the expansion tank of the low-pressure expansion tank is connected to the D suction manifold; the D pressure relief pipe of the low-pressure expansion tank is connected with the D exhaust manifold; and an oil return pipe of the low-pressure expansion tank is connected with an oil return header D.

The utility model discloses an in the preferred embodiment, further include carry cold unit including carrying cold solution tank, solution pump, D evaporimeter, medium temperature level evaporimeter, high temperature level heat exchanger, terminal heat exchanger integration, temperature control valve, electric switch valve, solenoid valve, check valve and check valve, the solution pump has parallelly connected L group, each the check valve is all installed to the export of solution pump, and the import is all got liquid in carrying cold solution tank, the solution pump export is finally assembled a house steward, from house steward respectively the connecting tube to D evaporimeter, medium temperature level evaporimeter and high temperature level heat exchanger, each pipeline carries out on-off control through electric switch valve, the solution play liquid pipeline of D evaporimeter, medium temperature level evaporimeter and high temperature level heat exchanger assembles terminal liquid supply house steward through the check valve, sends to the integrated import of terminal heat exchanger.

The utility model has the advantages that:

the utility model discloses a long-span low temperature refrigerating system for improved proof box, through the design of optimizing, in the high temperature stage of cooling stage, each D compressor can be according to parallelly connected mode work, only need open one of them can satisfy cold volume requirement when beginning higher case temperature, along with the case temperature reduction, increase the number of the units of opening gradually until parallelly connected each unit is opened entirely, be favorable to reducing refrigerating system part size configuration like this very much, realize high efficiency operation and energy-conservation; and when the temperature of the test box is reduced to be below a certain temperature, the state of the D compressor which originally works in parallel is changed into the following state through the combined action of the shunt three-way switch valve and the through switch valve: one part of the compressors D is still in a parallel state and becomes a low-temperature stage of the double-stage unit, the other part of the compressors D in parallel connection is switched to a high-temperature stage of the double-stage unit, and the two parts of the compressors D form a serial state, so that the high-temperature stage unit integrally operates according to the double-stage unit, and the high pressure ratio of the operation of the unit is avoided. When the temperature of the box is continuously reduced, all the units operate in an integral overlapping mode, so that the defect that the configuration capacity of the compressor cannot be exerted due to overlarge specific volume during the refrigerating operation of the single high-temperature working medium is overcome; even if the compressor unit operates in a cascade mode, the system can still realize the single-stage and double-stage switching of the high-temperature-stage unit, and prevent the high-pressure-ratio operation of each stage of compressor unit as much as possible. The defects of large unit size, high manufacturing cost and large power distribution caused by overlarge refrigerating capacity and huge configuration under high-temperature working conditions during unit configuration are avoided, and the high efficiency of the unit is ensured; meanwhile, the defects of large operation pressure ratio, low efficiency and unsafe operation of all levels of units of the conventional design system of the whole system under the large-span low-temperature working condition are overcome, and the safe operation of the units is ensured. The pressure ratio is reduced, so that the clearance loss of the compressor during the refrigeration operation is reduced, and the operation efficiency of the compressor is improved; but also is beneficial to obtaining lower temperature; the natural cooling capacity is fully utilized in the cooling process, the high evaporation temperature of the refrigerating unit is always ensured, and the refrigerating efficiency of the unit is maintained at any time. The system is suitable for the overlapping refrigeration occasions with the temperature range from normal temperature to below-60 ℃ in the box body, and is particularly suitable for the occasions with variable temperature requirements.

Drawings

Fig. 1 is a schematic view of the overall structure of a large-span cryogenic refrigeration system for a test chamber according to the preferred embodiment of the present invention;

fig. 2 is a schematic structural diagram of a cascade refrigeration unit low-temperature stage unit in a large-span low-temperature refrigeration system for an improved test box in the preferred embodiment of the invention;

fig. 3 is a schematic structural diagram of a cascade refrigeration unit high-temperature-stage unit in a large-span low-temperature refrigeration system for an improved test box according to the preferred embodiment of the invention;

fig. 4 is a schematic structural diagram of a refrigerating unit in a large-span cryogenic refrigeration system for a test chamber according to an embodiment of the present invention.

The reference numbers in the figures illustrate:

1: low-temperature-stage unit, 2: high-temperature-stage unit, 3: cold-carrying unit, 4: cooling water circulation integration, 11: cooling water outlet header pipe, 12: cooling water inlet manifold, 13: oil cooler, 14: d precooler, 15: d evaporator, 21: oil cooler, 22: g condenser, 23: intermediate-temperature stage evaporator, 24: condenser evaporator, 31: high-temperature-stage heat exchanger.

101: low-pressure expansion tank, 102: compressor, 103: d relief valve, 104: d pressure relief tube, 105: d suction manifold, 106: through switching valve, 107: shunt three-way switching valve, 108: d suction pipe, 109: d exhaust manifold, 110: cooling water low temperature level unit water supply inlet tube, 111: cooling water low-temperature level unit water supply wet return, 112: d-oil separator, 113: oil return pipe D, 116: d precooler cooling water inlet and outlet pipe, 118: solenoid valves a, 119: liquid ejection line solenoid valve, 121: throttle valve, 122: solenoid valves b, 123: thermostatic expansion valve, 124: d evaporator return pipe, 125: d economizer, 126: d economizer return pipe, 127: d liquid jet pipe, 128: d return oil header, 129: d exhaust manifold, 130: d exhaust pipe, 131: check valve, 132: solenoid valve c, 133: d return pipe, 134: low pressure expansion tank return line, 135: main pipe of expansion tank, 136: and an oil return valve.

201: g compressor, 202: g suction pipe, 203: g suction manifold, 204: g economizer return pipe, 205: solenoid valves aa, 206: g gas branch return gas manifold, 207: g gas-liquid separator, 208: cooling water high-temperature stage unit water supply wet return, 209: cooling water high-temperature stage unit water supply inlet tube, 210: g exhaust manifold, 211: g oil separator, 213: oil G return pipe, 214: g oil-cooled cooling water inlet and outlet pipe, 215: g condenser cooling water inlet and outlet pipe, 216: g return air manifold, 218: solenoid valves bb, 219: solenoid valve cc, 220: throttle valves aa, 221: g economizer, 223: solenoid valve dd, 224: throttle valve bb, 226: solenoid valve ee, 227: throttle valve cc, 229: g return oil header, 230: g exhaust manifold, 231: g exhaust pipe, 232: check valves aa, 233: solenoid valves ff, 234: g an oil return pipe.

301: cold-carrying solution tank, 302: solution pump, 304: check valve aaa, 307: high-temperature heat exchanger cooling water inlet and outlet pipe, 308: end supply header, 309: end heat exchanger integration, 310: end heat exchanger solution circulation pipe, 311: temperature adjustment control valve, 312: solenoid valve aaa, 314: terminal solution return pipe, 315: electric switch valve, 316: a check valve bbb.

Detailed Description

The present invention is further described with reference to the following drawings and specific embodiments so that those skilled in the art can better understand the present invention and can implement the present invention, but the embodiments are not to be construed as limiting the present invention.

Examples

The utility model discloses a large-span low temperature refrigerating system for modified proof box, it is shown with reference to figure 1 ~ 4, including overlapping refrigerated high temperature level unit 2, low temperature level unit 1, cold carrier group 3 to and all rather than the cooling water of intercommunicationLoop integration 4. A condensing evaporator 24 is arranged between the high-temperature-stage unit 2 and the low-temperature-stage unit 1. An intermediate-temperature-stage evaporator 23 is arranged between the cold-carrying unit 3 and the high-temperature-stage unit 2. And a D evaporator 15 is arranged between the cold carrying unit 3 and the low-temperature-level unit 1. The cryogenic stage train 1 includes M parallel D compressors 102. The suction ends of the M D compressors 102 are all connected to the D suction manifold 105, and the discharge ends are all connected to the D suction manifold 129. Preceding M₁Stage and rear M₂A through switch valve 106 and a shunt three-way switch valve 107 are respectively arranged on a D suction manifold 105 and a D suction manifold 129 between the platform D compressors 102, wherein M is M₁+M₂And M is₁≤M₂. The angle valve side of the three-way flow dividing switch valve 107 communicates with the D suction manifold 105. In the optimized design, the high-temperature unit 2 and the low-temperature unit 1 are mainly linked through the condensing evaporator 24, and the condensing heat of the low-temperature unit 1 and the refrigerating capacity generated by the high-temperature unit 2 are exchanged through the condensing evaporator 24 during the overlapping refrigerating operation; the cold-carrying unit 3 is mainly linked with the high-temperature unit 2 through the medium-temperature evaporator 23, and the circulating coolant of the cold-carrying unit 3 can be cooled by the medium-temperature evaporator 23 as required; the cold-carrying unit 3 is mainly linked with the low-temperature-level unit 1 through the D evaporator 15, and the circulating secondary refrigerant of the cold-carrying unit 3 can be sent to the D evaporator 15 to be cooled by the D evaporator 15 as required; the cooling water circulation assembly 4 can provide cooling water for the high-temperature-stage unit 2, the low-temperature-stage unit 1 and the cold carrier unit 3. The M D compressors 102 in the low-temperature stage unit 1 can be connected in full parallel or in total series as required through the through switch valve 106 on the D suction manifold 105 and the shunt three-way switch valve 107 on the D suction manifold 129, and the D compressors 102 can be connected in full parallel or in total series when the temperature of the tank is slightly higher and operate in single stage, and can be connected in total series when the temperature of the tank is slightly lower and operate in double stage. The specific implementation process is that in the high-temperature stage of the cooling stage, each D compressor 102 can work in a parallel connection mode, only one of the compressors needs to be started to meet the requirement of cooling capacity when the higher tank temperature is started, and the number of started compressors is gradually increased along with the reduction of the tank temperature until all the parallel units are fully started, so that the size configuration of components of the refrigeration system is reduced, the high-efficiency operation is realized, and the energy is saved; while the temperature of the test box is reduced to a certain temperatureNext, the combined operation of the three-way switching valve 107 and the through switching valve 106 changes the state of the D compressor 102, which originally operates in parallel, to: one part of the D compressors 102 is still in a parallel state and becomes a low-temperature stage of the double-stage unit, the other part of the D compressors 102 connected in parallel is switched to a high-temperature stage of the double-stage unit, and the two parts of the D compressors 102 form a serial state, so that the high-temperature stage unit 2 integrally operates according to the double-stage unit, and the high pressure ratio of the unit operation is avoided. When the temperature of the box is continuously reduced, all the units operate in an integral overlapping mode, so that the defect that the configuration capacity of the compressor cannot be exerted due to overlarge specific volume during the refrigerating operation of the single high-temperature working medium is overcome; even if the compressor operates in a cascade mode, the system can still realize the single-stage and double-stage switching of the high-temperature stage unit 2, and prevent the large-pressure-ratio operation of each stage of compressor unit as much as possible. The defects of large unit size, high manufacturing cost and large power distribution caused by overlarge refrigerating capacity and huge configuration under high-temperature working conditions during unit configuration are avoided, and the high efficiency of the unit is ensured; meanwhile, the defects of large operation pressure ratio, low efficiency and unsafe operation of all levels of units of the conventional design system of the whole system under the large-span low-temperature working condition are overcome, and the safe operation of the units is ensured. The pressure ratio is reduced, so that the clearance loss of the compressor during the refrigeration operation is reduced, and the operation efficiency of the compressor is improved; but also is beneficial to obtaining lower temperature; the natural cooling capacity is fully utilized in the cooling process, the high evaporation temperature of the refrigerating unit is always ensured, and the refrigerating efficiency of the unit is maintained at any time. The system is suitable for the overlapping refrigeration occasions with the temperature range from normal temperature to below-60 ℃ in the box body, and is particularly suitable for the occasions with variable temperature requirements.

The number of the D compressors 102 is two to five. Preferably three.

Specifically, the low-temperature-stage unit 1 further includes a D oil separator 112, a D oil cooler 13, a D precooler 14, a D economizer 125, a condenser evaporator 24, a D evaporator 15, a low-pressure expansion tank 101, a temperature-controlled expansion valve 123, a D relief valve 103, a plurality of solenoid valves 118, 119, 122, 132, a throttle valve 121, a check valve 131, and a connecting pipe.

A D discharge pipe 130 is provided at the discharge end of each of the D compressors 102. The D-side exhaust pipes 130 are provided with check valves 131. Each D exhaust pipe 130 converges to a D exhaust manifold 129; a D suction pipe 108 is provided at a suction end of each D compressor 130. Each D suction pipe 108 is connected after being converged by the D suction manifold 105; the D oil return pipe 133 of each D compressor 102 is provided with an electromagnetic valve c132, each D oil return pipe 133 is connected out of a D oil return collecting pipe 128, the D oil return collecting pipe 128 originates from a D oil return pipe 113 at the outlet of the D oil separator 112 and cools lubricating oil through the D oil cooler 13, and an oil thermostatic valve is arranged on the oil return pipe connected with the D oil cooler 13; the D spray pipes 127 of the D compressors 102 are provided with spray line solenoid valves 119, and the D spray pipes 127 are connected to the liquid inlet pipe of the supercooling side pipe of the D economizer 125.

The D suction manifold 105 is provided with a through switch valve 106, and the D suction manifold 105 is connected with the D evaporator 15 through a D evaporator air return pipe 124; a three-way diverter switch valve 107 is arranged on the D exhaust manifold 129, and the angle valve side of the three-way diverter switch valve 107 is connected to the D suction manifold 105; the evaporation side return line of the D economizer 125 is also connected to the D suction manifold 105 via a D economizer return line 126.

The working medium outlet pipe of the D oil separator 112 is connected with a working medium inlet of a D precooler 14, a working medium outlet of the D precooler 14 is connected with a condensing side inlet of a condensing evaporator 24, a condensing side outlet of the condensing evaporator 24 is divided into two pipelines after passing through an electromagnetic valve a118 and is respectively connected with two side pipe orifices of an evaporating side and a supercooling side of a D economizer 125, wherein the evaporating side pipeline is provided with an electromagnetic valve b122 and a temperature control type expansion valve 123 which are evaporated and gasified by the D economizer 125, and the outlet is connected with a D suction manifold 105 through a D economizer return air pipe 126; the supercooling side inlet pipeline is respectively connected with three pipelines which are respectively connected back to the liquid spraying ports of the D compressors 102 through D liquid spraying pipes 127 where liquid spraying pipe electromagnetic valves 119 are located, the supercooling side inlet header pipe of the D economizer 125 enters the D economizer 125, the circulating working medium is supercooled in the D economizer 125, then passes through the throttle valve 121 and enters the D evaporator 15 to cool the circulating secondary refrigerant of the secondary cooling unit 3, and at the moment, the circulating working medium is overheated after the D evaporator 15 absorbs heat, flows back to the D air suction collecting pipe 105 through a D evaporator air return pipe 124 and is finally pumped back by the D compressors 102.

The low-pressure expansion tank 101 is connected to the rest of the low-temperature stage unit 1 through three pipelines: is connected with a D suction manifold 105 through an expansion tank main pipe 135; the D pressure release pipe 104 is connected with a D exhaust main pipe 109, and the on-off state is controlled by a D pressure release valve 103 on the pipeline in a thermal mode; the low-pressure expansion tank return pipe 134 is connected with a D return manifold 128, and the on-off is controlled by a return valve 136.

In the low-temperature stage unit 1 composed of three D compressors in the cascade refrigeration unit, the installation positions of the through-switch valve 106 mounted on the D suction manifold 105 and the shunt three-way switch valve 107 mounted on the D discharge manifold 129, and the connection positions of the relevant connection pipes are specified as follows: the three D compressors 102 in the original parallel state are separated by the straight-through switch valve 106 and the shunt three-way switch valve 107, only two D compressors are continuously in the parallel state, and the other D compressor is in an independent state; the angle valve side of the flow dividing three-way switch valve 107 is connected with the D suction manifold 105 of the D compressor 102 in the independent state, the evaporation side return pipe of the D economizer 125 is connected with the D suction manifold 105 of the D compressor 102 in the independent state, and the position of the working medium on the evaporation side of the D evaporator 15 which is overheated and flows back to the D suction manifold 105 is positioned on the side of two continuous parallel states; the connection position of the D discharge header 109 and the D discharge header 129 is located on the discharge side of the D compressor 102 in the independent state.

The through-cut switch valve 106 and the shunt three-cut switch valve 107 in the low-temperature stage unit 1 are electrically operated valves associated with each other. The working mode is as follows: when the straight-through switch valve 106 is in a straight-through opening state as required, the shunt three-way switch valve 107 is in a straight-through state at the same time, and at the moment, the M D compressors 102 are connected in parallel; when the through switch valve 106 is in a closed state as required, the shunt three-way switch valve 107 is simultaneously in an angle-pass state, and at the moment, a high-temperature stage unit formed by M parallel D compressors 102 is switched into a two-stage compressor unit, wherein M is connected with the two-stage compressor unit in parallel₂The platform parallel D compressor 102 forms a low-pressure stage unit of the two-stage unit, M₁The stage-parallel D compressor 102 constitutes a high-pressure stage unit of the two-stage unit.

The high-temperature stage unit 2 includes M G compressors 201, G oil separators 211, G oil coolers 21, G economizers 221, medium-temperature stage evaporators 23, evaporative condensers 24, G gas-liquid separators 207, a plurality of solenoid valves 205, 218, 219, 223, 226, 233, a plurality of throttle valves 220, 224, 227, check valves 232, and connecting pipes

The check valve 232 is installed on the G exhaust pipe 231 of each G compressor 201. The G exhaust pipes 231 are all collected to the G exhaust manifold 230; the G suction pipes 202 of the G compressors 201 are all connected out of a G suction header 203; electromagnetic valves ff233 are arranged on G oil return pipes 234 of the G compressors 201, the G oil return pipes 234 are connected out of G oil return collecting pipes 229, the G oil return collecting pipes 229 start G oil return pipes 213 from oil outlets at the lower part of the G oil separator 211, lubricating oil is cooled through the G oil cooler 21, and oil constant temperature valves are arranged on oil return pipes connected with the G oil cooler 21; an electromagnetic valve aa205 is installed on each G economizer return air pipe 204 returning from the G economizer 221 to the compressor. The G suction manifold 203 is connected with the outlet of the G gas-liquid separator 207 through a G gas-component return gas manifold 206, and the inlet of the G gas-liquid separator 207 is connected in parallel with the outlet of the evaporation side of the condensation evaporator 24 and the outlet of the evaporation side of the intermediate-temperature stage evaporator 23 through a G gas-return gas manifold 216; the G exhaust manifold 230 is connected to the inlet of the G oil separator 211 via the G exhaust manifold 210.

A working medium outlet pipe of the G oil separator 211 is connected to a working medium side inlet of the G condenser 22, a working medium side outlet of the G condenser 22 is divided into two pipelines after passing through an electromagnetic valve bb218 and is respectively connected to pipe orifices on two sides of an evaporation side and a supercooling side of the G economizer 221, wherein the pipeline on the evaporation side is provided with an electromagnetic valve cc219 and a throttle valve aa220, the electromagnetic valve cc219 and the throttle valve aa220 are evaporated and gasified by the G economizer 221, and an outlet of the electromagnetic valve is connected to an economizer interface of the G compressor 201 through a G economizer return pipe 204; the inlet main pipe at the supercooling side enters the G economizer 221, the circulating working medium is supercooled in the G economizer and then divided into two pipelines which are respectively connected with the condensing evaporator 24 and the medium-temperature-stage evaporator 23 through an electromagnetic valve ee226 and a throttle valve cc227, the on-off of each electromagnetic valve ee226 and the on-off of each electromagnetic valve dd223 are controlled, cold energy is provided for the low-temperature-stage unit 1 at the condensing-stage evaporator 24 according to the requirement, or cold energy is provided for the circulating secondary refrigerant of the secondary cooling unit 3 at the medium-temperature-stage evaporator 23 according to the requirement, and the circulating working medium after being respectively gasified is pumped back by the G compressor 201 through the G gas-liquid separator 207.

The cold-carrying unit 3 comprises a cold-carrying solution tank 301, a solution pump 302, a D evaporator 15, a medium-temperature stage evaporator 23, a high-temperature stage heat exchanger 31, a tail end heat exchanger assembly 309, a temperature regulation control valve 311, an electric switch valve 315, an electromagnetic valve aaa312, a plurality of check valves 304 and 316 and a connecting pipe.

The solution pump 302 has L groups connected in parallel. Preferably, L is 1 to 3 groups, each group can be provided with a plurality of solution pumps 302 which can be respectively connected in parallel for use or set for standby, and the solution pumps respectively bear the liquid supply circulation tasks at different temperature levels during refrigeration operation. Each solution pump 302 has a check valve 304 at its outlet and a cold solution tank 301 at its inlet. The outlet of the solution pump 302 is finally converged to a main pipe, and the main pipe is respectively connected with the D evaporator 15, the medium-temperature-stage evaporator 23 and the high-temperature-stage heat exchanger 31, and the on-off control of each pipeline is performed through an electric switch valve 315. Solution outlet pipelines of all the heat exchangers are converged to a tail end liquid supply header pipe 308 through check valves aaa304, and are sent to an inlet of a tail end heat exchanger assembly 309, and the solution enters the tail end heat exchanger assembly 309 through a tail end heat exchanger solution circulation pipe 310 to exchange heat and then flows back to the cold carrying solution tank 301. In order to control the heat exchange amount of the end heat exchanger assembly 309, a temperature control valve 311 is installed between the solution inlet and outlet pipes of the end heat exchanger assembly 309. In order to facilitate the solution contained in the end heat exchanger assembly 309 to directly flow back to the cold-carrying solution tank 301 when necessary, an end solution return pipe 314 which flows back to the cold-carrying solution tank 301 is installed on the solution inlet pipeline of the end heat exchanger assembly 309, and the on-off of the pipeline is controlled by a solenoid valve aaa 312.

The cooling water circulation assembly 4 comprises a cooling tower, a circulating water pump, a connecting pipeline, a cooling water inlet manifold 12, a cooling water outlet manifold 11, a cooling water high-temperature-level unit water supply inlet pipe 209, a cooling water high-temperature-level unit water supply return pipe 208, a G oil-cooled cooling water inlet pipe 214, a G condenser cooling water inlet pipe 215, a cooling water low-temperature-level unit water supply inlet pipe 110, a cooling water low-temperature-level unit water supply return pipe 111, a D oil cooler cooling water inlet pipe 115, a D precooler cooling water inlet pipe 116 and a high-temperature-level heat exchanger cooling water inlet pipe 307; the cooling water is cooled and driven by the cooling water cooling and driving assembly 4, and is respectively sent to the G oil cooler 21, the G condenser 22, the D oil cooler 13, the D precooler 14 and the high-temperature-level heat exchanger 31 through cooling water supply and return pipelines, and after heat is released by each heat exchanger according to needs, the cooling water cooling and driving assembly 4 is cooled again to circulate. Specifically, the cold carrier set 3 and the cooling water circulation assembly 4 can be connected through the high-temperature heat exchanger 31, and the high-temperature coolant of the cold carrier set 3 can be cooled by the cooling water in a relatively low-temperature state as required; when the high-temperature-stage unit 2 operates, the cooling water circulation assembly 4 respectively provides cooling water for the G oil cooler 21 and the G condenser 22 of the high-temperature-stage unit 2; when the low-temperature-level unit 1 operates, the cooling water circulation assembly 4 respectively provides cooling water for the D oil cooler 13 and the D precooler 14 of the low-temperature-level unit 1.

Although this system explains with 2 low temperature stage compressor G compressors 201 and 3 low temperature stage compressor D compressors 102 in theory the utility model discloses the theory of operation, actually the high temperature stage can use 2 to 5 compressors to constitute the unit, the low temperature stage also can adopt 1 to 3 to constitute the low temperature stage unit, in fact, nevertheless, the compressor is too much, not only brings the unit cost too high, and in actual operation, can be because the uninstallation scope is too big brings hidden danger such as the oil return is not smooth, consequently more numbers do not have engineering meaning.

The utility model discloses an among the proof box low temperature refrigerating system, be in several G compressors 207 under the parallel state, no matter the operation is at single-stage state, presses down or work at doublestage operating condition, can open one or several as required. If the system operates in a single stage, only 1 compressor is needed to be started under the highest temperature working condition, and the other G compressors 207 connected in parallel are gradually increased or the load is increased along with the change of the demand of the system evaporation temperature on the refrigerating capacity; in dual stage operation, the principle of capacity of the elevator group is the same as in single stage.

In a word, the embodiment of the utility model provides a can utilize cooling water, single-stage compression refrigerating unit, second grade compression refrigerating unit, overlapping unit, combine the overlapping unit of second grade compression to provide cold volume for the secondary refrigerant respectively in proper order.

The coolant circulation of embodiments of the present invention can also be performed with the external coolant circulating between the end heat exchanger assembly 309 and the coolant tank and the internal coolant circulating between the battery heat exchanger and the coolant tank separately, which still belongs to the coolant circulation protection range.

The embodiment of the utility model provides an in each group solution pump 302 of cold-carrying unit adopt the mode that sets up respectively for making things convenient for the one-to-one to three kinds of high, well, low temperature heat exchanger's confession liquid mode, and each pump can each other be for reserve in the use. The actual flow can also be set in a one-to-one correspondence manner, or only a single set of pumps can be set to supply liquid for three heat exchangers simultaneously, and the changes do not violate the basic spirit of the utility model.

The utility model discloses only show and constitute the necessary part and the pipeline of the embodiment of the utility model, and neglected some part and pipeline, include usually for the part that makes things convenient for system maintenance and improves the required increase of reliability, like the relevant drier-filter of refrigeration pipeline, oil filter, look the liquid mirror, stop valve, even spray liquid CIC subassembly, the maintenance valve that water route, secondary refrigerant pipeline are commonly used, still for example the utility model discloses do not show low temperature level vapour and liquid separator in low temperature level unit 1 of embodiment, generally recommend, screw rod machine return gas suction inlet can not use the gas branch, piston machine return gas suction inlet suggests to use the gas branch; the addition of components and piping by the actual system does not violate the basic spirit of the present invention.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutes or changes made by the technical personnel in the technical field on the basis of the utility model are all within the protection scope of the utility model. The protection scope of the present invention is subject to the claims.

Claims (10)

1. The utility model provides a long-span cryogenic refrigeration system for modified proof box which characterized in that: the system comprises a cascade refrigeration high-temperature-level unit, a cascade refrigeration low-temperature-level unit, a cold-carrying unit and a cooling water circulation integration which are communicated with the cascade refrigeration high-temperature-level unit, the low-temperature-level unit and the cold-carrying unit; be provided with the condensation evaporimeter between high-temperature level unit and the low-temperature level unit, be provided with the medium temperature level evaporimeter between year cold machine group and the high-temperature level unit, be provided with the D evaporimeter between year cold machine group and the low-temperature level unit, the low-temperature level unit includes M parallelly connected D compressors, M platform the end of breathing in of D compressor all communicates in D collector of breathing in, and the exhaust end all communicates in D collector of breathing in, M preceding M₁Stage and rear M₂A D suction manifold and a D suction manifold between the D compressors are respectively provided with a through openingA closing valve and a shunt three-way switch valve, wherein M is M₁+M₂And M is₁≤M₂And the angle valve side of the flow dividing three-way switch valve is communicated with the D air suction manifold.

2. The improved large-span cryogenic test chamber system of claim 1, wherein: the D compressor is provided with a D oil return pipe and a D liquid spray pipe, the D oil return pipe is provided with an electromagnetic valve, each D oil return pipe is connected out of a D oil return collecting pipe and communicated to a D oil separator, the D oil separator is communicated with a D oil cooler, and an oil return pipeline connected with the D oil cooler is provided with an oil thermostatic valve; and liquid spraying pipeline electromagnetic valves are arranged on the D liquid spraying pipes of the D compressor, and each D liquid spraying pipe is connected with a liquid inlet pipe of a supercooling side pipeline of the D economizer.

3. The improved large-span cryogenic test chamber system of claim 2, wherein: the air suction manifold is connected with the evaporator D; and an evaporation side gas return pipe of the D economizer is connected to a D gas suction header.

4. The improved large-span cryogenic test chamber system of claim 2, wherein: a working medium outlet pipe of the D oil separator is connected with a working medium inlet of a D precooler, a working medium outlet of the D precooler is connected with a condensing side inlet of a condensing evaporator, the condensing side outlet of the condensing evaporator is divided into two pipelines after passing through an electromagnetic valve, and the two pipelines are respectively connected with pipe orifices on two sides of an evaporation side and a supercooling side of a D economizer, wherein the pipeline on the evaporation side is provided with the electromagnetic valve and a temperature control type expansion valve, and the outlet of the D economizer is connected with a D suction manifold through a gas return pipe of the D economizer; and the supercooling side inlet pipeline of the D economizer is respectively connected with three pipelines, and the three pipelines are respectively connected with the liquid spraying ports of the D compressors through the D liquid spraying pipes where the liquid spraying pipe electromagnetic valves are positioned.

5. An improved large-span cryogenic test chamber system as claimed in any one of claims 1 to 4, wherein: the number of the D compressors is 2 to 5.

6. The improved large-span cryogenic test chamber system of claim 1, wherein: the direct-connection switch valve and the shunt three-way switch valve are electric valves with associated electric actions, when the direct-connection switch valve is closed and the shunt three-way switch valve is simultaneously opened, a high-temperature-stage unit formed by M parallel-connection D compressors is switched into a two-stage compressor unit, wherein M is connected with the two-stage compressor unit in parallel₂The platform parallel D compressors form a low-pressure stage unit of the two-stage unit, M₁The platform parallel connection D compressor forms a high-pressure stage unit of the double-stage unit.

7. The improved large-span cryogenic test chamber system of claim 1, wherein: the high-temperature-stage unit comprises M G compressors, exhaust ends of the M G compressors are communicated with G exhaust manifolds, air suction ends of the M G compressors are communicated with G air suction manifolds, oil return ends of the M G compressors are communicated with G oil return manifolds after passing through an electromagnetic valve, the G oil return manifolds are communicated with G oil separators, the G oil separators are communicated with G oil coolers, and oil return pipelines connected with the G oil coolers are provided with oil thermostatic valves; the gas return pipes of the G economizers and the G compressor are provided with electromagnetic valves, the G gas suction manifold is connected with the outlet of the G gas-liquid separator through a G gas-component gas return main pipe, and the inlet of the G gas-liquid separator is connected with the evaporation side outlet of the condensation evaporator and the evaporation side outlet of the medium-temperature grade evaporator in parallel through the G gas return main pipe; and the G exhaust manifold is connected to the inlet of the G oil separator through a G exhaust manifold.

8. The improved large-span cryogenic test chamber system of claim 7, wherein: a working medium outlet pipe of the G oil separator is connected to a working medium side inlet of the G condenser, a working medium side outlet of the G condenser is divided into two pipelines after passing through an electromagnetic valve and is respectively connected to pipe orifices on two sides of an evaporation side and a supercooling side of the G economizer, the electromagnetic valve and a throttle valve are arranged on the pipeline on the evaporation side, and the outlet of the G economizer is connected to an economizer interface of the G compressor through a return air pipe of the G economizer; the inlet main pipe at the supercooling side enters the G economizer, the circulating working medium is supercooled in the G economizer and then divided into two pipelines which are respectively connected with the condensing evaporator and the medium temperature grade evaporator through the electromagnetic valve and the throttle valve.

9. The improved large-span cryogenic test chamber system of claim 1, wherein: the low-temperature-stage unit comprises a low-pressure expansion tank, and an expansion tank main pipe of the low-pressure expansion tank is connected with a D suction manifold; the D pressure relief pipe of the low-pressure expansion tank is connected with the D exhaust manifold; and an oil return pipe of the low-pressure expansion tank is connected with an oil return header D.

10. The improved large-span cryogenic test chamber system of claim 1, wherein: carry cold unit including carrying cold solution case, solution pump, D evaporimeter, medium temperature level evaporimeter, high temperature level heat exchanger, terminal heat exchanger integration, temperature control valve, electric switch valve, solenoid valve, check valve and check valve, the solution pump has parallelly connected L group, each the solution pump export all installs the check valve, and the import all gets liquid in carrying cold solution case, a house steward is finally assembled to solution pump export, from house steward union coupling to D evaporimeter, medium temperature level evaporimeter and high temperature level heat exchanger respectively, and each pipeline carries out on-off control through electric switch valve, the solution play liquid pipeline of D evaporimeter, medium temperature level evaporimeter and high temperature level heat exchanger assembles terminal confession liquid main through the check valve, sends to the integrated import of terminal heat exchanger.

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