Energy-saving refrigerated dryer
By using a refrigerated dryer with both variable frequency and fixed frequency systems connected in series, the problem of large energy loss in traditional refrigerated dryers under extremely low loads is solved, achieving precise control of cooling capacity and system energy saving.
Patent Information
- Application Number
- CN202520350774.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-03-03
AI Technical Summary
Traditional refrigerated dryers suffer from unstable pressure dew point control under extremely low loads, resulting in significant energy loss and poor energy-saving performance.
By employing a series connection of variable frequency and fixed frequency dual systems, and controlling the cooling capacity through a three-in-one heat exchanger and dual refrigeration systems, the compressor energy utilization is maximized.
It achieves precise control of cooling capacity under different loads, maximizes the use of compressor energy, and achieves system energy-saving effect.
Smart Images
Figure CN223869689U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of dryer technology, specifically to an energy-saving refrigerated dryer. Background Technology
[0002] Refrigerated dryers are a major component of air compressor after-treatment systems. Traditional refrigerated dryers mostly use a single refrigeration system to cool compressed air. When the compressed air flow rate changes, the refrigeration system adjusts the cooling capacity of the compressor through a bypass valve. Regardless of whether it's a variable frequency or fixed frequency system, its lower limit processing capacity is often limited by multiple factors (such as not being able to go too low). Therefore, for compressed air drying under extremely low loads, pressure dew point control will also fluctuate. When the system operating conditions are reduced, energy loss is very large, failing to achieve energy-saving effects. Utility Model Content
[0003] To address the shortcomings of existing technologies, this utility model provides an energy-saving refrigerated dryer that overcomes these deficiencies. Its reasonable design utilizes a dual-system approach of variable frequency and fixed frequency connected in series to control the required cooling capacity, thereby maximizing the use of the compressor's energy and achieving system energy savings.
[0004] To achieve the above objectives, this utility model provides the following technical solution:
[0005] An energy-saving refrigerated dryer includes a three-in-one heat exchanger, which is provided with a precooling chamber, a first heat exchange chamber, a second heat exchange chamber, and a gas-liquid separation chamber. The upper end of the precooling chamber is provided with a gas inlet, the lower end of the precooling chamber is connected to the first heat exchange chamber, the lower end of the first heat exchange chamber is connected to the second heat exchange chamber, the second heat exchange chamber is connected to the inlet end of the gas-liquid separation chamber, and the outlet end of the gas-liquid separation chamber passes through the precooling chamber and is connected to the outlet channel.
[0006] A first heat exchange tube is installed in the first heat exchange chamber, and a second heat exchange tube is installed in the second heat exchange chamber. The inlet and outlet ends of the first heat exchange tube are connected to the outlet and inlet ends of the first refrigeration system, respectively, and the inlet and outlet ends of the second heat exchange tube are connected to the outlet and inlet ends of the second refrigeration system, respectively.
[0007] Preferably, the first refrigeration system includes a fixed-frequency compressor, a first oil separator, a first condenser, and a first gas-liquid separator. The output end of the fixed-frequency compressor is connected to the liquid input end of the first oil separator via a pipeline. The output end of the first oil separator is connected to the input end of the first condenser via a pipeline. The output end of the first condenser is connected to the input end of a first liquid storage tank via a pipeline. The upper end of the first liquid storage tank is connected to one end of a first input pipeline, and the other end of the first input pipeline is connected to the inlet end of a first heat exchange tube. A thermostatic expansion valve is installed on the first input pipeline. The outlet end of the first heat exchange tube is connected to the input end of the first gas-liquid separator via a pipeline, and the output end of the first gas-liquid separator is connected to the gas input end of the fixed-frequency compressor via a pipeline.
[0008] Preferably, a first solenoid valve and a first drying filter are also installed on the first input pipeline.
[0009] Preferably, the second refrigeration system includes a variable frequency compressor, a second oil separator, a second condenser, and a second gas-liquid separator. The output end of the variable frequency compressor is connected to the liquid input end of the second oil separator via a pipeline. The output end of the second oil separator is connected to the input end of the second condenser via a pipeline. The output end of the second condenser is connected to the input end of the second liquid storage tank via a pipeline. The upper end of the second liquid storage tank is connected to one end of a second input pipeline, and the other end of the second input pipeline is connected to the inlet end of a second heat exchange tube. An electronic expansion valve is installed on the second input pipeline. The outlet end of the second heat exchange tube is connected to the input end of the second gas-liquid separator via a pipeline, and the output end of the second gas-liquid separator is connected to the gas input end of the variable frequency compressor via a pipeline.
[0010] Preferably, a second solenoid valve and a second drying filter are also installed on the second input pipeline.
[0011] Preferably, the gas output end of the second oil separator is also connected to one end of a bypass pipeline, the other end of which is connected to the inlet end of the second heat exchange tube, and a bypass valve is installed on the bypass pipeline.
[0012] Preferably, the lower end of the gas-water separation chamber is connected to a drain via a pipeline.
[0013] Preferably, a wire mesh demister is fixedly installed in the inner cavity of the gas-water separation chamber.
[0014] This invention provides an energy-saving refrigerated dryer with the following advantages: High-temperature, high-humidity compressed air from the air compressor first enters the pre-cooling chamber through the gas inlet at the top, where it exchanges heat with the processed cooling air for pre-cooling, initially reducing its temperature. Then, it enters the first heat exchange chamber to exchange heat with the refrigerant in the first heat exchange tube, further lowering the compressed air temperature. Next, it enters the second heat exchange chamber to exchange heat with the refrigerant in the second heat exchange tube, further reducing the compressed air temperature and causing condensation. Then, it enters the gas-liquid separation chamber from the bottom of the second heat exchange chamber, where liquid water is separated by gravity, resulting in nearly dry cold air. The dried cold air then flows upwards into the pre-cooling chamber to exchange heat again with subsequent high-temperature, high-humidity compressed air. This process not only pre-cools the subsequent high-temperature, high-humidity air but also allows the processed cold air to reheat, ultimately yielding dry air. Furthermore, by employing a dual-system approach of variable frequency and fixed frequency connected in series, the required cooling capacity is controlled, thereby maximizing the use of the compressor's energy and achieving system energy-saving effects. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in this utility model or the prior art, the accompanying drawings used in the description of the prior art will be briefly introduced below.
[0016] Figure 1 A schematic diagram of the structure of this utility model;
[0017] Explanation of the labels in the diagram:
[0018] 1. Three-in-one heat exchanger; 11. Pre-cooling chamber; 12. First heat exchange chamber; 13. Second heat exchange chamber; 14. Gas-water separation chamber; 15. Gas inlet; 16. Outlet channel; 17. First heat exchange tube; 18. Second heat exchange tube;
[0019] 21. Fixed-frequency compressor; 22. First oil separator; 23. First condenser; 24. First gas-liquid separator; 25. First liquid storage tank; 26. First input pipeline; 27. Thermal expansion valve; 28. First solenoid valve; 29. First dryer filter;
[0020] 31. Variable frequency compressor; 32. Second oil separator; 33. Second condenser; 34. Second gas-liquid separator; 35. Second liquid storage tank; 36. Second input pipeline; 37. Electronic expansion valve; 38. Second solenoid valve; 39. Second dryer filter; 310. Bypass pipeline; 311. Bypass valve;
[0021] 5. Drainage device; 6. Wire mesh demister. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings.
[0023] Example 1, as Figure 1 As shown, an energy-saving refrigerated dryer includes a three-in-one heat exchanger 1. The three-in-one heat exchanger 1 is provided with a precooling chamber 11, a first heat exchange chamber 12, a second heat exchange chamber 13 and a gas-liquid separation chamber 14. The upper end of the precooling chamber 11 is provided with a gas inlet 15. The lower end of the precooling chamber 11 is connected to the first heat exchange chamber 12. The lower end of the first heat exchange chamber 12 is connected to the second heat exchange chamber 13. The second heat exchange chamber 13 is connected to the inlet end of the gas-liquid separation chamber 14. The outlet end of the gas-liquid separation chamber 14 passes through the precooling chamber 11 and is connected to the outlet channel 16.
[0024] A first heat exchange tube 17 is installed in the first heat exchange chamber 12, and a second heat exchange tube 18 is installed in the second heat exchange chamber 13. The inlet and outlet ends of the first heat exchange tube 17 are connected to the outlet and inlet ends of the first refrigeration system, respectively, and the inlet and outlet ends of the second heat exchange tube 18 are connected to the outlet and inlet ends of the second refrigeration system, respectively.
[0025] Working principle:
[0026] During operation, the high-temperature and high-humidity compressed air output by the air compressor first enters the pre-cooling chamber 11 through the gas inlet 15 at the upper end of the pre-cooling chamber 11 to exchange heat with the processed cooling air for pre-cooling, thereby initially reducing the temperature. Then it enters the first heat exchange chamber 12 to exchange heat with the refrigerant in the first heat exchange tube 17, thereby reducing the temperature of the compressed air. After that, it enters the second heat exchange chamber 13 to exchange heat with the refrigerant in the second heat exchange tube 18, thereby further reducing the temperature of the compressed air and causing condensation. Then it enters the gas-water separation chamber 14 from the lower end of the second heat exchange chamber 13, thereby separating liquid water through gravity separation to obtain nearly dry cold air. After being dried, the cold air flows upward into the pre-cooling chamber 11 to exchange heat with the subsequent high-temperature and high-humidity compressed air. This not only pre-cools the subsequent high-temperature and high-humidity air but also allows the treated cold air to be warmed up, ultimately resulting in dry air that is 3-5°C lower in temperature than the air entering the heat exchanger.
[0027] In this embodiment, the first refrigeration system uses a fixed-frequency compressor 21 for refrigeration, and the second refrigeration system uses a variable-frequency compressor 31 for refrigeration. Furthermore, the refrigerant circulating in the first refrigeration system and the refrigerant circulating in the second refrigeration system are different refrigerants.
[0028] Due to the influence of ambient temperature and air consumption at the air compressor station, the operating cooling capacity range of refrigerated dryers is very wide. The required dehumidification cooling capacity of the refrigeration system varies between 13% and 100%. Conventional refrigerated dryers use hot gas bypass to achieve the required cooling capacity, which is obviously not energy-efficient. This invention controls the required cooling capacity by using a first refrigeration system and a second refrigeration system in series. Because the variable frequency compressor 31 has a minimum cooling capacity, a single variable frequency compressor system cannot meet the minimum cooling capacity requirement to achieve full coverage of the required cooling capacity of the entire system. Therefore, a dual system control of variable frequency and fixed frequency is adopted. Firstly, the cooling capacity of the second refrigeration system of the variable frequency compressor 31 is slightly greater than that of the first refrigeration system of the fixed frequency compressor 21. Therefore, when the required cooling capacity is greater than that of the variable frequency compressor 31, the fixed frequency compressor 21 can be turned on to run at full load, while the variable frequency compressor 31 is reduced to a suitable speed to maximize the energy utilization of the refrigeration end.
[0029] Specifically, when the required cooling capacity is 13%-60%, only the second refrigeration system of the variable frequency compressor 31 needs to be turned on, and the system's cooling capacity is controlled according to the compressor speed. When the required cooling capacity reaches 60%, the fixed frequency compressor 21 operates at full load, while the variable frequency compressor 31 reduces its speed to a lower level. When the required cooling capacity is 60%-100%, both the fixed frequency compressor 21 and the variable frequency compressor 31 operate simultaneously to control the system's cooling capacity. This control method achieves full coverage of the actual required cooling capacity, with changes in cooling capacity entirely dependent on the speed control of the variable frequency compressor 31. This allows the compressor's energy to be used to the maximum extent, thus achieving system energy-saving effects.
[0030] Example 2, as a further preferred embodiment of Example 1, the first refrigeration system includes a fixed-frequency compressor 21, a first oil separator 22, a first condenser 23, and a first gas-liquid separator 24. The output end of the fixed-frequency compressor 21 is connected to the liquid input end of the first oil separator 22 via a pipeline. The output end of the first oil separator 22 is connected to the input end of the first condenser 23 via a pipeline. The output end of the first condenser 23 is connected to the input end of the first liquid storage tank 25 via a pipeline. The upper end of the first liquid storage tank 25 is connected to one end of the first input pipeline 26, and the other end of the first input pipeline 26 is connected to the inlet end of the first heat exchange tube 17. A thermostatic expansion valve 27 is installed on the first input pipeline 26. The outlet end of the first heat exchange tube 17 is connected to the input end of the first gas-liquid separator 24 via a pipeline, and the output end of the first gas-liquid separator 24 is connected to the gas input end of the fixed-frequency compressor 21 via a pipeline.
[0031] Therefore, during operation, the first refrigeration system first discharges high-temperature, high-pressure refrigerant through the fixed-frequency compressor 21, then enters the first oil separator 22 through pipelines, and then enters the first condenser 23 for heat exchange to obtain medium-temperature, high-pressure refrigerant. Next, it enters the first liquid receiver 25 for buffering, and then enters the first input pipeline 26. The thermal expansion valve 27 on the first input pipeline 26 throttles the flow, effectively controlling the superheat of the fixed-frequency system to obtain low-temperature, low-pressure refrigerant. Then, it enters the first heat exchange tube 17 from the inlet end, where it exchanges heat with the compressed air output from the air compressor, cooling and dehumidifying the compressed air. Afterward, the refrigerant flows out from the outlet end of the first heat exchange tube 17 and enters the first gas-liquid separator 24 for gas-liquid separation, and then returns to the fixed-frequency compressor 21 through pipelines to complete the entire refrigeration cycle.
[0032] In Example 3, as a further preferred embodiment of Example 2, a first solenoid valve 28 and a first dryer filter 29 are also installed on the first input pipe 26. The first solenoid valve 28 is used to control the opening and closing of the entire first refrigeration system, and the first dryer filter 29 is used to further dry and filter the refrigerant.
[0033] Example 4, as a further preferred embodiment of Example 1, the second refrigeration system includes a variable frequency compressor 31, a second oil separator 32, a second condenser 33, and a second gas-liquid separator 34. The output end of the variable frequency compressor 31 is connected to the liquid input end of the second oil separator 32 via a pipeline. The output end of the second oil separator 32 is connected to the input end of the second condenser 33 via a pipeline. The output end of the second condenser 33 is connected to the input end of the second liquid storage tank 35 via a pipeline. The upper end of the second liquid storage tank 35 is connected to one end of the second input pipeline 36, and the other end of the second input pipeline 36 is connected to the inlet end of the second heat exchange tube 18. An electronic expansion valve 37 is installed on the second input pipeline 36. The outlet end of the second heat exchange tube 18 is connected to the input end of the second gas-liquid separator 34 via a pipeline, and the output end of the second gas-liquid separator 34 is connected to the gas input end of the variable frequency compressor 31 via a pipeline.
[0034] Therefore, during operation of the second refrigeration system, the high-temperature, high-pressure refrigerant is first discharged through the variable frequency compressor 31, then enters the second oil separator 32 through pipelines, and then enters the second condenser 33 for heat exchange to obtain medium-temperature, high-pressure refrigerant. It then enters the second liquid receiver 35 for buffering, and then enters the second input pipeline 36. The electronic expansion valve 37 on the second input pipeline 36 throttles the flow, effectively and precisely controlling the superheat of the variable frequency system to obtain low-temperature, low-pressure refrigerant. It then enters the second heat exchange tube 18 from the inlet end, where it exchanges heat with the compressed air output from the air compressor, cooling and dehumidifying the compressed air. Afterwards, the refrigerant flows out from the outlet end of the second heat exchange tube 18 and enters the second gas-liquid separator 34 for gas-liquid separation, and then returns to the variable frequency compressor 31 through pipelines to complete the entire refrigeration cycle.
[0035] In Example 6, as a further preferred embodiment of Example 5, a second solenoid valve 38 and a second dryer filter 39 are also installed on the second input pipe 36. The second input pipe 36 enables the opening and closing control of the entire second refrigeration system, while the second dryer filter 39 provides further drying and filtration for the refrigerant.
[0036] In Example 4, as a further preferred embodiment of Example 2, the gas output end of the second oil separator 32 is also connected to one end of a bypass pipe 310, and the other end of the bypass pipe 310 is connected to the inlet end of the second heat exchange tube 18. A bypass valve 311 is installed on the bypass pipe 310. By setting the bypass pipe 310 and the bypass valve 311, the bypass valve 311 can be opened in extreme cases to avoid ice blockage and cracking in the variable frequency system pipeline.
[0037] In Example 7, as a further preferred embodiment of Example 1, the lower end of the gas-water separation chamber 14 is connected to the drain 5 via a pipe. The separated liquid water is discharged through the drain 5.
[0038] Example 8, as a further preferred embodiment of Example 1, includes a wire mesh demister 6 fixedly installed inside the gas-water separation chamber 14. The wire mesh demister 6 further dehumidifies the cold air entering the gas-water separation chamber 14, ensuring its dryness.
[0039] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. An energy-saving freeze dryer, characterized in that: The device includes a three-in-one heat exchanger (1), which is provided with a precooling chamber (11), a first heat exchange chamber (12), a second heat exchange chamber (13) and a gas-water separation chamber (14). The upper end of the precooling chamber (11) is provided with a gas inlet (15). The lower end of the precooling chamber (11) is connected to the first heat exchange chamber (12). The lower end of the first heat exchange chamber (12) is connected to the second heat exchange chamber (13). The second heat exchange chamber (13) is connected to the inlet end of the gas-water separation chamber (14). The outlet end of the gas-water separation chamber (14) passes through the precooling chamber (11) and is connected to the outlet channel (16). The first heat exchange chamber (12) is equipped with a first heat exchange tube (17), and the second heat exchange chamber (13) is equipped with a second heat exchange tube (18). The inlet and outlet ends of the first heat exchange tube (17) are connected to the outlet and inlet ends of the first refrigeration system, respectively, and the inlet and outlet ends of the second heat exchange tube (18) are connected to the outlet and inlet ends of the second refrigeration system, respectively.
2. The energy-saving refrigerated dryer according to claim 1, characterized in that: The first refrigeration system includes a fixed-frequency compressor (21), a first oil separator (22), a first condenser (23), and a first gas-liquid separator (24). The output end of the fixed-frequency compressor (21) is connected to the liquid input end of the first oil separator (22) through a pipeline. The output end of the first oil separator (22) is connected to the input end of the first condenser (23) through a pipeline. The output end of the first condenser (23) is connected to the input end of the first liquid storage tank (25) through a pipeline. The upper end of the first liquid storage tank (25) is connected to one end of the first input pipeline (26). The other end of the first input pipeline (26) is connected to the inlet end of the first heat exchange tube (17). A thermostatic expansion valve (27) is installed on the first input pipeline (26). The outlet end of the first heat exchange tube (17) is connected to the input end of the first gas-liquid separator (24) through a pipeline. The output end of the first gas-liquid separator (24) is connected to the gas input end of the fixed-frequency compressor (21) through a pipeline.
3. The energy-saving refrigerated dryer according to claim 2, characterized in that: The first input pipeline (26) is also equipped with a first solenoid valve (28) and a first dryer filter (29).
4. The energy-saving refrigerated dryer according to claim 1, characterized in that: The second refrigeration system includes a variable frequency compressor (31), a second oil separator (32), a second condenser (33), and a second gas-liquid separator (34). The output end of the variable frequency compressor (31) is connected to the liquid input end of the second oil separator (32) through a pipeline. The output end of the second oil separator (32) is connected to the input end of the second condenser (33) through a pipeline. The output end of the second condenser (33) is connected to the input end of the second liquid storage tank (35) through a pipeline. The upper end of the second liquid storage tank (35) is connected to one end of the second input pipeline (36). The other end of the second input pipeline (36) is connected to the inlet end of the second heat exchange tube (18). An electronic expansion valve (37) is installed on the second input pipeline (36). The outlet end of the second heat exchange tube (18) is connected to the input end of the second gas-liquid separator (34) through a pipeline. The output end of the second gas-liquid separator (34) is connected to the gas input end of the variable frequency compressor (31) through a pipeline.
5. An energy-saving refrigerated dryer according to claim 4, characterized in that: A second solenoid valve (38) and a second dryer filter (39) are also installed on the second input pipeline (36).
6. An energy-saving refrigerated dryer according to claim 4, characterized in that: The gas output end of the second oil separator (32) is also connected to one end of a bypass pipe (310), and the other end of the bypass pipe (310) is connected to the inlet end of the second heat exchange tube (18). A bypass valve (311) is installed on the bypass pipe (310).
7. An energy-saving refrigerated dryer according to claim 1, characterized in that: The lower end of the gas-water separation chamber (14) is connected to the drain (5) via a pipeline.
8. An energy-saving refrigerated dryer according to claim 1, characterized in that: A wire mesh demister (6) is fixedly installed in the inner cavity of the gas-water separation chamber (14).