CN103335437B - One-stage throttling incomplete-inter-cooling double-working-condition refrigerating system - Google Patents

Abstract

The invention discloses a one-stage throttling incomplete-inter-cooling double-working-condition refrigerating system capable of achieving variable-flow single-stage vapor compression cycle and variable-flow one-stage throttling incomplete inter-cooling. The one-stage throttling incomplete-inter-cooling double-working-condition refrigerating system comprises a plurality of sets of variable-flow compression condensing units which are connected among a high-temperature air suction pipeline, a low-temperature air suction pipeline and a high-pressure liquid supply pipeline in parallel. Each set of variable-flow compression condensing unit is composed of a low-pressure constant-flow compressor, a low-pressure variable-flow compressor, a high-pressure variable-flow compressor, a first one-way valve, a second one-way valve, a third one-way valve, a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a condenser, an intercooler and a throttling valve. Through opening or closing of each valve, air can be sucked by the high-temperature air suction pipeline so that single-stage compression refrigeration cycle can supply liquid to the high-pressure liquid supply pipeline, and air can also be sucked by the low-temperature air suction pipeline so that double-stage compression refrigeration cycle can supply liquid to the high-pressure liquid supply pipeline.

Description

Incomplete cooling in the middle of one throttling and double working condition refrigeration system

technical field

The invention relates to the technical field of refrigeration, in particular to a two-stage compression refrigeration system with primary throttling intermediate incomplete cooling and dual-working conditions that adjusts the cooling capacity by changing the refrigerant flow rate.

Background technique

The existing two-stage compression refrigeration system used for freezing cold storage usually uses temperature control to start and stop the compressor. When the temperature of the cold storage reaches the temperature set by the thermostat, the refrigeration system stops working; when the temperature rises to the upper limit set by the thermostat, The cooling system is switched on. There is a contradiction in such a system. When the temperature difference between startup and shutdown is relatively large, the food stored in the frozen storage will lose water and dryness due to different freezing rates, and food quality will decline; when the temperature difference between startup and shutdown is relatively small, refrigeration The frequent opening of the system will not only increase the power consumption, but also reduce the service life of the refrigeration system. In addition, the existing two-stage compression refrigeration system has a fixed high-pressure and low-pressure volume ratio of 1:3 or 1:2. For refrigeration systems with changing condensing temperatures, since the high-pressure and low-pressure volume ratios cannot be adjusted, the refrigeration system is not in the best condition. Work, high energy consumption.

The multi-connected air conditioning system composed of multiple compression condensing units and multiple indoor evaporators realizes the control of cooling capacity by changing the refrigerant flow rate. The system is flexible in operation and easy to control, and is widely used in the field of air conditioning. However, the existing multi-connected air-conditioning systems are all single-stage compression refrigeration systems, which are only applicable to the field of air-conditioning, and are not suitable for freezing cold storage systems with low temperatures.

For the parallel system of frozen cold storage (lower suction temperature, usually requires a two-stage compression system) and cold storage (higher suction temperature, usually requires a single-stage vapor compression system), it is often necessary to use single and double-stage vapor compression systems. Separately configured, the one-time investment of the system is large, and the adjustment of the cooling capacity is completely realized by starting and stopping.

Contents of the invention

The purpose of the present invention is to solve the technical defect in the prior art that the cooling capacity adjustment is completely realized by starting and shutting down, and to provide a parallel connection of multiple sets of variable flow compression condensing units, which can not only realize the variable flow single-stage vapor compression cycle, but also A refrigeration system with a two-stage compression cycle that can realize variable flow, one throttling, and incomplete cooling in the middle.

The technical scheme adopted for realizing the purpose of the present invention is:

A dual-working mode refrigeration system with incomplete cooling in the middle of one throttling, characterized in that it includes multiple sets of variable flow compression condensing units connected in parallel between the high-temperature suction pipeline, the low-temperature suction pipeline, and the high-pressure liquid supply pipeline; Each set of variable flow compression condensing units consists of a low-pressure constant-flow compressor, a low-pressure variable-flow compressor, a high-pressure variable-flow compressor, a first check valve, a second check valve, a third check valve, a first valve, The second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the condenser, the intercooler and the throttling valve; The high-temperature suction pipeline is connected, the inlet of the second valve is connected to the low-temperature suction pipeline, and the outlet of the intercooler tube side is connected to the high-pressure liquid supply pipeline; the outlet of the first valve and the The outlet of the second valve is respectively connected to the suction port of the low-pressure constant-flow compressor, the suction port of the low-pressure variable-flow compressor, and the inlet of the fourth valve, and the exhaust port of the low-pressure constant-flow compressor is connected to the The inlet of the first one-way valve is connected, the exhaust port of the low-pressure variable flow compressor is connected with the inlet of the second one-way valve, and the outlet of the first one-way valve is connected in parallel with the outlet of the second one-way valve respectively It is connected with the third valve inlet, the fifth valve inlet and the shell-side outlet of the intercooler, and the third valve outlet is connected in parallel with the fourth valve outlet to suck air from the high-pressure variable flow compressor The exhaust port of the high-pressure variable flow compressor is connected to the inlet of the third check valve, and the outlet of the third check valve is connected in parallel with the outlet of the fifth valve and then connected to the inlet of the condenser. The outlet of the condenser is respectively connected with the inlet of the sixth valve and the inlet of the pipe side of the intercooler, and the outlet of the sixth valve is connected with the inlet of the shell side of the intercooler through the throttle valve; by controlling the The opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve can realize the single-stage compression refrigeration cycle from the high-temperature suction pipeline to the high-pressure Liquid is supplied by the liquid supply pipeline, and air can be sucked from the low-temperature suction pipeline to realize primary throttling, intermediate incomplete cooling, and a two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline.

Incomplete cooling in the middle of primary throttling and dual working condition throttling refrigeration system after cooling, including multiple sets of variable flow compression condensing units connected in parallel between the high-temperature suction pipeline, low-temperature suction pipeline and high-pressure liquid supply pipeline; The variable flow compression condensing unit consists of a low pressure constant flow compressor, a low pressure variable flow compressor, a high pressure variable flow compressor, a first one-way valve, a second one-way valve, a third one-way valve, a first valve, a second valve, third valve, fourth valve, fifth valve, sixth valve, condenser, intercooler and throttling valve; the first valve inlet and the The high-temperature suction pipeline is connected, the inlet of the second valve is connected with the low-temperature suction pipeline, and the pipe-side outlet of the intercooler is respectively connected with the high-pressure liquid supply pipeline and the inlet of the sixth valve; The outlet of a valve and the outlet of the second valve are respectively connected to the suction port of the low-pressure constant-flow compressor, the suction port of the low-pressure variable-flow compressor, and the inlet of the fourth valve, and the discharge port of the low-pressure constant-flow compressor The air port is connected to the inlet of the first one-way valve, the exhaust port of the low-pressure variable flow compressor is connected to the inlet of the second one-way valve, and the outlet of the first one-way valve is connected to the inlet of the second one-way valve. The outlets are connected in parallel with the third valve inlet, the fifth valve inlet and the shell-side outlet of the intercooler, and the third valve outlet is connected with the fourth valve outlet in parallel with the high pressure variable flow rate The suction port of the compressor is connected, the discharge port of the high-pressure variable flow compressor is connected with the inlet of the third one-way valve, the outlet of the third one-way valve is connected in parallel with the outlet of the fifth valve, and then connected with the condenser The inlet is connected, the outlet of the condenser is connected with the inlet of the pipe side of the intercooler, and the outlet of the sixth valve is connected with the inlet of the shell side of the intercooler through the throttle valve; by controlling the first valve, The opening or closing of the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve can realize the single-stage compression refrigeration cycle from the high-temperature suction pipeline to the high-pressure liquid supply pipeline. Liquid supply, inhalation from the low-temperature suction pipeline to achieve a throttling intermediate incomplete cooling two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline.

The low-pressure constant-flow compressor is any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor.

The low-pressure variable-flow compressor and the high-pressure variable-flow compressor are any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor. By adjusting the variable voltage of the DC motor, the flow regulation of the refrigerant can also be realized by unloading and loading the refrigerant.

The condenser is an air-cooled condenser, a water-cooled condenser or an evaporative condenser; the intercooler is a plate heat exchanger or a casing heat exchanger.

The throttle valve is an electronic expansion valve, a thermal expansion valve, a capillary or an orifice.

Compared with prior art, the beneficial effect of the present invention is:

1. Energy saving: the refrigeration system of the present invention is composed of variable flow compression condensing units connected in parallel, each group of variable flow compression condensing units includes a low-pressure constant-flow compressor, a low-pressure variable-flow compressor and a high-pressure variable-flow compressor, which are input to the freezer The refrigerant flow rate of the cold storage can be adjusted according to the load requirements, which overcomes the technical defect that the cooling capacity adjustment is completely realized by starting and stopping, and the refrigeration system will not be opened frequently.

2. The temperature of the cold storage is constant: since the refrigerant flow of the refrigeration system can be adjusted, the system can automatically adjust the refrigerant flow according to the load change of the frozen storage. After reaching the set temperature, the refrigeration system will work at a lower refrigerant flow to maintain the frozen Keeping the temperature of the cold storage avoids fluctuations in the internal temperature of the cold storage, effectively reducing the dehydration and dry consumption of food caused by temperature fluctuations.

3. Less one-time investment: The variable flow compression condensing unit in the refrigeration system of the present invention can not only suck air from the high-temperature suction pipeline to realize single-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline, but also can supply liquid from the high-temperature suction pipeline. The above-mentioned low-temperature suction pipeline sucks air to realize one-time throttling and incomplete cooling in the middle, and the two-stage compression refrigeration cycle supplies liquid to the high-pressure liquid supply pipeline. Parallel variable flow compression condensing units do not interfere with each other in work, and can realize variable flow operation, one machine with multiple functions, reducing the one-time investment.

4. The unit can realize the best working condition: the refrigeration system of the present invention is composed of variable flow compression condensing units connected in parallel, and each group of variable flow compression condensing units includes a low-pressure constant-flow compressor, a low-pressure variable-flow compressor and a high-pressure variable-flow compressor. The machine overcomes the shortcomings of fixed high and low pressure volume ratios in the prior art, and realizes the adjustable volume ratio. No matter how the working conditions change, the refrigeration system is always working in the best state, with low energy consumption.

5. Modularization: High-pressure variable-flow compressors and low-pressure variable-flow compressors can use compressors with the same rated input power, which is conducive to system adjustment and easy repair and maintenance, and it is easier to realize system modularization.

Description of drawings

Fig. 1 is a schematic diagram of a throttling refrigerating system in the present invention with primary throttling, intermediate incomplete cooling, dual working conditions, and pre-cooling throttling.

Fig. 2 is a schematic diagram of a throttling refrigerating system of the present invention with primary throttling, intermediate incomplete cooling, dual working conditions and post-cooling throttling.

In the figure: 1. High temperature suction pipeline, 2. Low temperature suction pipeline, 3. High pressure liquid supply pipeline, 4. Low pressure constant flow compressor, 5. Low pressure variable flow compressor, 6. High pressure variable flow compressor , 7-1. The first one-way valve, 7-2. The second one-way valve, 7-3. The third one-way valve, 8-1. The first valve, 8-2. The second valve, 8-3 .Third valve, 8-4. Fourth valve, 8-5. Fifth valve, 8-6. Sixth valve, 9. Condenser, 10. Intercooler, 11. Throttle valve.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

According to the different throttling positions, the double-working condition refrigeration system with primary throttling and incomplete cooling in the middle of the present invention is divided into a throttling refrigeration system with incomplete cooling in the middle of primary throttling and a dual-working condition before cooling and a duplex refrigeration system with incomplete cooling in the middle of primary throttling. Throttle the refrigeration system after cooling down.

Example 1

Fig. 1 is a schematic diagram of a throttling refrigeration system in the present invention with a throttling in the middle of incomplete cooling and dual working conditions before cooling, including parallel connections between the high-temperature suction pipeline 1, the low-temperature suction pipeline 2 and the high-pressure liquid supply pipeline 3 Multiple sets of variable flow compression condensing units, each set of variable flow compression condensing units consists of a low-pressure constant-flow compressor 4, a low-pressure variable-flow compressor 5, a high-pressure variable-flow compressor 6, a first one-way valve 7-1, a second Two one-way valve 7-2, the third one-way valve 7-3, the first valve 8-1, the second valve 8-2, the third valve 8-3, the fourth valve 8-4, the fifth valve 8- 5. The sixth valve 8-6, the condenser 9, the intercooler 10 and the throttle valve 11 are composed. The inlet of the first valve 8-1 in each group of variable flow compression condensing units is connected to the high-temperature suction pipeline 1, and the inlet of the second valve 8-2 is connected to the low-temperature suction pipeline 2 , the pipe side outlet of the intercooler 10 is connected to the high-pressure liquid supply pipeline 3, and the outlet of the first valve 8-1 and the outlet of the second valve 8-2 are respectively connected to the low-pressure constant flow compressor 4 The suction port, the suction port of the low-pressure variable-flow compressor 5 is connected to the inlet of the fourth valve 8-4, and the exhaust port of the low-pressure constant-flow compressor 4 is connected to the inlet of the first one-way valve 7-1 connection, the exhaust port of the low-pressure variable flow compressor 5 is connected to the inlet of the second one-way valve 7-2, and the outlet of the first one-way valve 7-1 is connected to the outlet of the second one-way valve 7-2 After being connected in parallel, they are respectively connected to the inlet of the third valve 8-3, the inlet of the fifth valve 8-5 and the outlet of the shell side of the intercooler 10, and the outlet of the third valve 8-3 is connected to the outlet of the fourth valve 8-4 The outlet is connected in parallel to the suction port of the high-pressure variable flow compressor 6, the exhaust port of the high-pressure variable flow compressor 6 is connected to the inlet of the third one-way valve 7-3, and the third one-way valve The outlet of the valve 7-3 is connected in parallel with the outlet of the fifth valve 8-5 and then connected with the inlet of the condenser 9, and the outlet of the condenser 9 is respectively connected with the inlet of the sixth valve 8-6 and the intercooler 10 is connected to the pipe-side inlet, and the outlet of the sixth valve 8-6 is connected to the shell-side inlet of the intercooler 10 through the throttle valve 11 . By controlling the opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve, the single-stage compression refrigeration cycle can be realized by sucking air from the high-temperature suction pipeline Liquid is supplied to the high-pressure liquid supply pipeline, and air can be sucked from the low-temperature suction pipeline to realize a throttling intermediate incomplete cooling and a two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline.

The variable flow compression condensing unit in the throttling refrigerating system in the first throttling middle incomplete cooling dual-working condition cooling before the embodiment 1 can suck air from the high-temperature suction pipeline 1 to realize the single-stage compression refrigeration cycle to the high-pressure supply. The liquid pipeline 3 supplies liquid, and can suck air from the low-temperature suction pipeline 2 to realize primary throttling, intermediate incomplete cooling, and a two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline 3 . Parallel variable flow compression condensing units do not interfere with each other during work, and all can realize variable flow operation.

1. Inhale air from the high-temperature suction line 1 to realize a single-stage compression refrigeration cycle and supply liquid to the high-pressure liquid supply line 3:

The second valve 8-2, the third valve 8-3 and the sixth valve 8-6 in the variable flow compression condensing unit are closed, and the first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 are opened. The low-pressure refrigerant vapor returning from the cold storage to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4, the low-pressure variable-flow compressor 5, and the high-pressure variable-flow compressor 6 through the high-temperature suction pipeline 1 for compression. The high-pressure refrigerant vapor passes through the first one-way valve 7-1, the second one-way valve 7-2 and the third one-way valve 7-3 to the condenser 9 to be condensed into a high-pressure liquid, and then passes through the tube side of the intercooler 10 The inlet and outlet enter the high-pressure liquid supply pipeline 3 to supply liquid to the refrigerator.

2. Inhale air from the low-temperature suction line 2 to realize a two-stage compression refrigeration cycle and supply liquid to the high-pressure liquid supply line 3:

The first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 in the variable flow compression condensing unit are closed, and the second valve 8-2, the third valve 8-3 and the sixth valve 8-6 are opened. The low-pressure refrigerant vapor returning from the freezer to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4 and the low-pressure variable-flow compressor 5 through the low-temperature suction line 2 for one-stage compression, and the compressed medium-pressure superheats The steam refrigerant passes through the first one-way valve 7-1 and the second one-way valve 7-2 and mixes with the medium-pressure saturated steam refrigerant exiting from the shell side outlet of the intercooler 10 to form a medium-pressure superheated steam refrigerant and enters the high-pressure transformer. The second-stage compression is carried out in the flow compressor 6, and the compressed high-pressure superheated vapor refrigerant is condensed into a high-pressure liquid refrigerant by the condenser 9, and the condensed high-pressure liquid refrigerant is divided into two parts, and a part of the high-pressure liquid refrigerant is throttled The valve 11 throttles the medium-pressure saturated gas-liquid two-phase refrigerant, and then enters the intercooler 10 through the shell side inlet of the intercooler 10 to cool the high-pressure liquid refrigerant flowing through the tube side inlet to the tube side outlet of the intercooler 10, The other part of the high-pressure liquid refrigerant enters the intercooler 10 from the inlet of the tube side of the intercooler 10 to be cooled into a high-pressure supercooled liquid refrigerant, and the high-pressure supercooled liquid refrigerant comes out from the outlet of the tube side of the intercooler 10 through the high-pressure liquid supply pipeline 3 Supply liquid to the freezer.

Example 2

Fig. 2 is a schematic diagram of the throttling refrigerating system after throttling in the middle and incomplete cooling of the present invention, including the parallel connection between the high-temperature suction pipeline 1, the low-temperature suction pipeline 2 and the high-pressure liquid supply pipeline 3 Multiple sets of variable flow compression condensing units. Each group of variable flow compression condensing units includes a low-pressure constant-flow compressor 4, a low-pressure variable-flow compressor 5, a high-pressure variable-flow compressor 6, a first check valve 7-1, a second check valve 7-2, and a second check valve 7-2. Three check valves 7-3, first valve 8-1, second valve 8-2, third valve 8-3, fourth valve 8-4, fifth valve 8-5, sixth valve 8-6, Condenser 9, intercooler 10 and throttle valve 11. The inlet of the first valve 8-1 in each group of variable flow compression condensing units is connected to the high-temperature suction pipeline 1, and the inlet of the second valve 8-2 is connected to the low-temperature suction pipeline 2 , the pipe-side outlet of the intercooler 10 is connected to the inlet of the sixth valve 8-6 and the high-pressure liquid supply pipeline 3 respectively. The outlet of the first valve 8-1 and the outlet of the second valve 8-2 are respectively connected to the suction port of the low-pressure constant flow compressor 4, the suction port of the low-pressure variable flow compressor 5 and the fourth valve 8-4 inlet connection, the exhaust port of the low-pressure constant flow compressor 4 is connected to the inlet of the first check valve 7-1, the exhaust port of the low-pressure variable flow compressor 5 is connected to the second check valve 7-2 inlet connection, the outlet of the first one-way valve 7-1 is connected in parallel with the outlet of the second one-way valve 7-2, and then respectively connected to the inlet of the third valve 8-3 and the outlet of the fifth valve 8- 5 inlet is connected to the shell-side outlet of the intercooler 10, the outlet of the third valve 8-3 is connected in parallel with the outlet of the fourth valve 8-4 and then connected to the suction port of the high-pressure variable flow compressor 6, so The exhaust port of the high-pressure variable flow compressor 6 is connected to the inlet of the third one-way valve 7-3, and the outlet of the third one-way valve 7-3 is connected in parallel with the outlet of the fifth valve 8-5 and then connected to the outlet of the fifth valve 8-5. The inlet of the condenser 9 is connected, the outlet of the condenser 9 is connected to the inlet of the tube side of the intercooler 10, the outlet of the sixth valve 8-6 is connected to the inlet of the shell side of the intercooler 10 through the throttle valve 11 connect. By controlling the opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve, the single-stage compression refrigeration cycle can be realized by sucking air from the high-temperature suction pipeline Liquid is supplied to the high-pressure liquid supply pipeline, and air can be sucked from the low-temperature suction pipeline to realize a throttling intermediate incomplete cooling and a two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline.

The variable flow compression condensing unit in the throttling refrigeration system after primary throttling, intermediate incomplete cooling and dual working conditions cooling in Embodiment 2 can suck air from the high-temperature suction pipeline 1 to realize single-stage compression refrigeration cycle to high-pressure supply. The liquid pipeline 3 supplies liquid, and the low-temperature suction pipeline 2 can suck air to realize a two-stage compression refrigeration cycle to supply liquid to the high-pressure liquid supply pipeline 3 . Parallel variable flow compression condensing units do not interfere with each other during work, and all can realize variable flow operation.

1. Inhale air from the high-temperature suction line 1 to realize a single-stage compression refrigeration cycle and supply liquid to the high-pressure liquid supply line 3:

The second valve 8-2, the third valve 8-3 and the sixth valve 8-6 in the variable flow compression condensing unit are closed, and the first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 are opened. The low-pressure refrigerant vapor returning from the cold storage to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4, the low-pressure variable-flow compressor 5, and the high-pressure variable-flow compressor 6 through the high-temperature suction pipeline 1 for compression. The high-pressure refrigerant vapor passes through the first one-way valve 7-1, the second one-way valve 7-2 and the third one-way valve 7-3 to the condenser 9 to be condensed into a high-pressure liquid, and then passes through the tube side of the intercooler 10 The inlet and outlet enter the high-pressure liquid supply pipeline 3 to supply liquid to the refrigerator.

2. Inhale air from the low-temperature suction line 2 to realize a two-stage compression refrigeration cycle and supply liquid to the high-pressure liquid supply line 3:

The first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 in the variable flow compression condensing unit are closed, and the second valve 8-2, the third valve 8-3 and the sixth valve 8-6 are opened. The low-pressure refrigerant vapor returning from the freezer to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4 and the low-pressure variable-flow compressor 5 through the low-temperature suction line 2 for one-stage compression, and the compressed medium-pressure superheats The steam refrigerant passes through the first one-way valve 7-1 and the second one-way valve 7-2 and mixes with the medium-pressure saturated steam refrigerant exiting from the shell side outlet of the intercooler 10 to form a medium-pressure superheated steam refrigerant and enters the high-pressure transformer. The second-stage compression is performed in the flow compressor 6, and the compressed high-pressure superheated vapor refrigerant is condensed into a high-pressure liquid refrigerant through the condenser 9, and the condensed high-pressure liquid refrigerant enters the intercooler 10 from the side inlet of the intercooler 10 tube The intercooler is a high-pressure subcooled liquid refrigerant, which is divided into two parts from the side outlet of the intercooler 10 tube, and a part of the high-pressure supercooled liquid refrigerant is throttled by the throttle valve 11 to become a medium-pressure saturated gas-liquid The two-phase refrigerant enters the intercooler 10 through the shell-side inlet of the intercooler 10 to cool the high-pressure liquid refrigerant flowing through the tube-side inlet to the tube-side outlet of the intercooler 10, and the other part of the high-pressure supercooled liquid refrigerant passes through the high-pressure The liquid supply pipeline 3 supplies liquid to the freezer.

In the single-stage compression refrigeration cycle of the above-mentioned embodiment 1 and embodiment 2, the combination of the low-pressure constant-flow compressor 4, the low-pressure variable-flow compressor 5, and the high-pressure variable-flow compressor 6 meets the requirements of the single-stage compression refrigeration cycle under different load conditions. control of refrigerant flow.

In the two-stage compression refrigeration cycle of the above-mentioned embodiment 1 and embodiment 2, when the load of the freezer is small, the low-pressure variable-flow compressor 5 and the high-pressure variable-flow compressor 6 work at the same time, by adjusting the high-pressure variable-flow compressor 6, the low-pressure The refrigerant flow rate of the variable flow compressor 5 realizes the best high and low pressure volume ratio of the system; when the load of the freezer is large, the low pressure constant flow compressor 4, the low pressure variable flow compressor 5 and the high pressure variable flow compressor 6 work simultaneously , by adjusting the refrigerant flow rate of the low-pressure variable-flow compressor 5 and the high-pressure variable-flow compressor 6, the best high-low pressure volume ratio of the system is realized. The system can adjust the refrigerant flow in the two-stage compression refrigeration cycle according to the load change of the freezer.

The functions of the first one-way valve 6-1, the second one-way valve 6-2 and the third one-way valve 6-3 in the above-mentioned embodiment 1 and embodiment 2 are to prevent backflow when the compressor is not working.

In the above-mentioned embodiment 1 and embodiment 2: the low-pressure constant-flow compressor is any one of a scroll compressor, a rotary compressor, a screw compressor, a piston compressor, or other types of compressors. The low-pressure variable-flow compressor and the high-pressure variable-flow compressor are any one of a scroll compressor, a rotary compressor, a screw compressor, a piston compressor, or other types of compressors, and the variable flow method can be through By adjusting the frequency conversion of the AC motor or the variable voltage of the DC motor, the flow regulation of the refrigerant can also be realized by unloading and loading the refrigerant. The condenser is an air-cooled condenser, a water-cooled condenser, an evaporative condenser or other types of condensers. The throttling valve is any one of electronic expansion valve, thermal expansion valve, capillary or orifice throttling, or other throttling devices capable of reducing pressure. The intercooler may be a plate heat exchanger, a casing heat exchanger or other types of heat exchangers.

The valve of the present invention can be a manual valve or an electric valve, and can also be replaced by a three-way valve or a four-way valve.

In the specific application of the dual-working mode refrigeration system with one throttling and incomplete cooling in the middle of the present invention, the high-pressure variable-flow compressor and the low-pressure variable-flow compressor can use compressors with the same rated input power, which is beneficial to system adjustment and is convenient for maintenance and maintenance. maintenance, while making it easier to achieve modularization of the system.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (10)

1. A dual-working mode refrigeration system with incomplete cooling in the middle of one throttling, which is characterized in that it includes multiple sets of variable flow compression condensing systems connected in parallel between the high-temperature suction pipeline, the low-temperature suction pipeline and the high-pressure liquid supply pipeline. unit; each group of the variable flow compression condensing unit consists of a low-pressure constant-flow compressor, a low-pressure variable-flow compressor, a high-pressure variable-flow compressor, a first check valve, a second check valve, a third check valve, a first Valve, second valve, third valve, fourth valve, fifth valve, sixth valve, condenser, intercooler and throttling valve; the first valve in each group of variable flow compression condensing units The inlet is connected to the high-temperature suction pipeline, the inlet of the second valve is connected to the low-temperature suction pipeline, and the tube-side outlet of the intercooler is connected to the high-pressure liquid supply pipeline; the first valve The outlet and the outlet of the second valve are respectively connected to the suction port of the low-pressure constant-flow compressor, the suction port of the low-pressure variable-flow compressor and the inlet of the fourth valve, and the exhaust port of the low-pressure constant-flow compressor It is connected to the inlet of the first one-way valve, the exhaust port of the low-pressure variable flow compressor is connected to the inlet of the second one-way valve, and the outlet of the first one-way valve is connected in parallel with the outlet of the second one-way valve connected with the third valve inlet, the fifth valve inlet and the shell-side outlet of the intercooler respectively; the third valve outlet and the fourth valve outlet are connected in parallel to the high-pressure variable flow compressor The suction port is connected, the exhaust port of the high-pressure variable flow compressor is connected with the inlet of the third one-way valve, and the outlet of the third one-way valve is connected in parallel with the outlet of the fifth valve and then connected with the inlet of the condenser , the outlet of the condenser is respectively connected with the inlet of the sixth valve and the inlet of the pipe side of the intercooler, and the outlet of the sixth valve is connected with the inlet of the shell side of the intercooler through the throttle valve; by controlling The opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve can realize the single-stage compression refrigeration cycle from the high-temperature suction pipeline to all The high-pressure liquid supply pipeline is used to supply liquid, and the low-temperature suction pipeline can be sucked to realize a two-stage compression refrigeration cycle with incomplete cooling in the middle of a throttling to supply liquid to the high-pressure liquid supply pipeline. 2. The dual-working mode refrigeration system with incomplete cooling in the middle of primary throttling according to claim 1, wherein the low-pressure constant-flow compressor is a scroll compressor, a rotary compressor, a screw compressor, or a piston compressor any of the. 3. The dual-working-condition refrigerating system with incomplete cooling in the middle of primary throttling according to claim 1, characterized in that, the low-pressure variable-flow compressor and the high-pressure variable-flow compressor are scroll compressors and rotary compressors , screw compressor, piston compressor, the variable flow method is to adjust the frequency conversion of the AC motor or the variable voltage of the DC motor, or to realize the flow regulation of the refrigerant by unloading and loading the refrigerant. 4. The dual-working mode refrigeration system with incomplete cooling in the middle of primary throttling according to claim 1, wherein the condenser is an air-cooled condenser, a water-cooled condenser or an evaporative condenser; the intercooler It is a plate heat exchanger or a casing heat exchanger. 5 . The dual-working-condition refrigeration system with primary throttling and incomplete cooling in the middle according to claim 1 , wherein the throttling valve is an electronic expansion valve, a thermal expansion valve, a capillary tube or an orifice. 6 . 6. Incomplete cooling in the middle of primary throttling and double working condition throttling refrigeration system after cooling, which is characterized in that it includes multiple sets of variable flow rates connected in parallel between the high-temperature suction pipeline, low-temperature suction pipeline and high-pressure liquid supply pipeline Compression condensing unit; each group of the variable flow compression condensing unit consists of a low-pressure constant-flow compressor, a low-pressure variable-flow compressor, a high-pressure variable-flow compressor, a first check valve, a second check valve, a third check valve, The first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, a condenser, an intercooler and a throttling valve; A valve inlet is connected to the high-temperature suction pipeline, the second valve inlet is connected to the low-temperature suction pipeline, and the pipe side outlet of the intercooler is respectively connected to the high-pressure liquid supply pipeline and the sixth valve Inlet connection; the outlet of the first valve and the outlet of the second valve are respectively connected to the suction port of the low-pressure constant-flow compressor, the suction port of the low-pressure variable-flow compressor, and the inlet of the fourth valve. The outlet of the low-pressure constant-flow compressor is connected to the inlet of the first check valve, the outlet of the low-pressure variable-flow compressor is connected to the inlet of the second check valve, and the outlet of the first check valve is connected to the inlet of the first check valve. The outlet of the second one-way valve is connected in parallel with the inlet of the third valve, the inlet of the fifth valve and the outlet of the shell side of the intercooler, and the outlet of the third valve is connected in parallel with the outlet of the fourth valve. It is connected to the suction port of the high-pressure variable-flow compressor, the exhaust port of the high-pressure variable-flow compressor is connected to the inlet of the third one-way valve, and the outlet of the third one-way valve is connected in parallel with the outlet of the fifth valve. Then it is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the tube side of the intercooler, and the outlet of the sixth valve is connected to the inlet of the shell side of the intercooler through the throttle valve; by controlling The opening or closing of the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve can realize the single-stage compression refrigeration cycle from the high-temperature suction pipeline to all The high-pressure liquid supply pipeline is used to supply liquid, and the low-temperature suction pipeline can be sucked to realize a two-stage compression refrigeration cycle with incomplete cooling in the middle of a throttling to supply liquid to the high-pressure liquid supply pipeline. 7. The throttling refrigerating system after throttling in the middle of the primary throttling with incomplete cooling and dual working conditions after cooling according to claim 6, wherein the low-pressure constant-flow compressor is a scroll compressor, a rotary compressor, or a screw compressor , Any of the piston compressors. 8. The throttling refrigerating system after throttling in the middle of the primary throttling, incomplete cooling and dual working conditions after cooling according to claim 6, characterized in that, the low-pressure variable-flow compressor and the high-pressure variable-flow compressor are scroll compressors , Rotary compressor, screw compressor, piston compressor, the variable flow method is to adjust the frequency conversion of the AC motor or the variable voltage of the DC motor, or use the refrigerant unloading and loading method to realize the refrigerant flow regulation. 9. The throttling refrigeration system according to claim 6, characterized in that the condenser is an air-cooled condenser, a water-cooled condenser or an evaporative condenser; The intercooler mentioned above is a plate heat exchanger or a casing heat exchanger. 10. The throttling refrigerating system with primary throttling, intermediate incomplete cooling, dual working conditions and post-cooling throttling according to claim 6, wherein the throttling valve is an electronic expansion valve, a thermal expansion valve, a capillary tube or an orifice.