Heating and defrosting pipeline of refrigerating unit for vehicle

Abstract

The utility model discloses a heating and defrosting pipeline of a vehicle refrigerating unit, and belongs to the technical field of vehicle refrigerating units. The system mainly comprises a refrigerating circuit, the refrigerating circuit comprises a compressor, a condenser and an evaporator, a high-pressure steam outlet of the compressor is communicated with the condenser and the evaporator through a first pipeline and a second pipeline respectively, a first electromagnetic valve is arranged on the first pipeline, a second electromagnetic valve is arranged on the second pipeline, and an outlet of the condenser is connected with a first expansion valve. The first expansion valve communicates with an evaporator inlet, and an evaporator outlet communicates with a low-temperature steam return opening of the compressor. According to the utility model, the heating and defrosting efficiency is ensured, the pressure in the low-pressure system is controllable, the compressor is ensured to always operate in an ideal state range, and the service life of the refrigerating system is prolonged. The utility model is mainly used for refrigerating systems of refrigerated vehicles.

Description

Technical Field

[0001] This utility model belongs to the technical field of automotive refrigeration units, and more specifically, it relates to a heating and defrosting pipeline for automotive refrigeration units. Background Technology

[0002] Refrigerated vehicles need to operate nationwide, resulting in significant variations in the external ambient temperature of their refrigeration units. To better adapt to these operating conditions, the refrigeration units are typically equipped with a heating defrosting function. Currently, there are two main types of heating defrosting designs.

[0003] The first method uses a three-way reversing valve for defrosting and heating. Its working principle involves adding this valve to the high-pressure discharge line of the compressor. During normal cooling, the high-temperature, high-pressure Freon gas, compressed by the compressor, flows to the condenser through the three-way reversing valve. After being cooled by the condenser, it then passes through the expansion valve to the evaporator for further cooling, becoming a low-temperature, low-pressure liquid Freon that returns to the compressor. During defrosting, the high-temperature, high-pressure Freon gas is redirected by the three-way reversing valve, and all of it flows to the evaporator, thus heating and defrosting it. The advantage of this method is its high defrosting efficiency. The disadvantage is that the amount of Freon in the low-pressure system cannot be precisely controlled during defrosting. This may lead to the compressor running with liquid moisture during excessively low-temperature heating, potentially damaging the compressor. Alternatively, when maintaining an extremely high temperature inside the cargo box, the low-pressure system pressure may become too high, resulting in high discharge pressure and overloading the compressor, causing damage.

[0004] Another method uses a single solenoid valve for defrosting heating. The principle is to add a solenoid valve to the high-pressure discharge line of the compressor. During normal cooling, the high-temperature, high-pressure Freon gas flows directly to the condenser. After being cooled by the condenser, it passes through the expansion valve to the evaporator for further cooling, becoming a low-temperature, low-pressure liquid Freon that returns to the compressor. During defrosting heating, the solenoid valve is opened, allowing some of the high-temperature, high-pressure Freon gas to flow through the valve to the evaporator for heating and defrosting. The disadvantage is that during defrosting heating, the high-temperature, high-pressure Freon gas can simultaneously flow to both the condenser and evaporator, resulting in low Freon gas discharge pressure, low defrosting efficiency, and difficulty in controlling Freon levels in the low-pressure system. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a heating and defrosting pipeline for automotive refrigeration units. In fact, while ensuring heating and defrosting efficiency, the pressure in the low-pressure system is controllable, ensuring that the compressor always operates within the ideal range and extending the service life of the refrigeration system.

[0006] The aforementioned vehicle refrigeration unit heating and defrosting pipeline includes a refrigeration circuit, which includes a compressor, a condenser, and an evaporator. The high-pressure steam outlet of the compressor is connected to the condenser and the evaporator through pipeline one and pipeline two, respectively. A first solenoid valve is provided on pipeline one, and a second solenoid valve is provided on pipeline two. The condenser outlet is connected to a first expansion valve, the first expansion valve is connected to the evaporator inlet, and the evaporator outlet is connected to the low-temperature return steam port of the compressor.

[0007] Preferably, the first solenoid valve is a normally open solenoid valve, and the second solenoid valve is a normally closed solenoid valve.

[0008] Preferably, it also includes a liquid storage tank, a dryer filter, and a plate heat exchanger. The plate heat exchanger is provided with a first refrigerant circulation channel and a second refrigerant circulation channel. The outlet of the condenser is connected to the liquid storage tank, the liquid storage tank is connected to the dryer filter, the dryer filter is connected to the second refrigerant circulation channel, and the outlet of the second refrigerant circulation channel is connected to the first expansion valve through a third solenoid valve. The first expansion valve is connected to the evaporator through a distributor.

[0009] Preferably, it also includes a fourth solenoid valve and a second expansion valve. The outlet of the dryer filter is connected to the second expansion valve through the fourth solenoid valve. The second expansion valve is connected to the inlet of the first refrigerant circulation channel. The outlet of the first refrigerant circulation channel is connected to the medium-temperature return steam port of the condenser.

[0010] Preferably, the second solenoid valve is connected to the liquid storage tank through a check valve three, and a check valve two is provided between the outlet of the condenser and the liquid storage tank.

[0011] Preferably, the high-pressure steam outlet of the compressor is connected to the first solenoid valve and the second solenoid valve respectively through a one-way valve.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This invention adds a first solenoid valve and a second solenoid valve. During defrosting, the first solenoid valve is closed and the second solenoid valve is opened, allowing the high-temperature, high-pressure refrigerant gas to directly enter the evaporator for heating and defrosting. This heating and defrosting method is effective and efficient. When the temperature is too low, the refrigerant content in the low-pressure system is appropriately recovered or increased by utilizing the superheat of the suction gas, preventing the compressor from operating with liquid or refrigerant shortages and ensuring the compressor reaches its optimal operating state. As the low-pressure system pressure gradually increases, to prevent the compressor from overloading, the first solenoid valve can be opened, allowing some of the high-temperature, high-pressure refrigerant gas to enter the condenser for cooling and storage. This reduces the amount of refrigerant entering the low-pressure system, thereby lowering the low-pressure system pressure. This achieves controllable pressure within the low-pressure system while maintaining heating and defrosting efficiency, ensuring the compressor always operates within its ideal operating range and extending the service life of the refrigeration system. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of Example 1;

[0015] Figure 2 This is a structural schematic diagram from a certain perspective of Embodiment 2;

[0016] Figure 3 This is a structural schematic diagram from another perspective of Embodiment 2;

[0017] Figure 4 This is a schematic diagram of Example 2;

[0018] Figure 5 This is a reference diagram showing the front view of the present invention in use.

[0019] Figure 6 This is a reference diagram showing the back of the present invention in use.

[0020] In the diagram, 1. Compressor; 101. High-pressure steam outlet; 102. Low-temperature steam return outlet; 103. Medium-temperature steam return outlet; 2. First solenoid valve; 3. Second solenoid valve; 4. Condenser; 5. First expansion valve; 6. Evaporator; 7. Pipeline 2; 701. Check valve 3; 8. Pipeline 1; 801. Check valve 2; 9. Plate heat exchanger; 10. Liquid receiver; 11. Dryer filter; 12. Fourth solenoid valve; 13. Generator; 14. Check valve 1; 15. Third solenoid valve; 16. Liquid distributor; 17. Second expansion valve. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] The directional terms used in the detailed description paragraphs are only for the convenience of those skilled in the art to understand the technical solutions described in this application based on the visual orientation shown in the accompanying drawings. Unless otherwise expressly specified and limited, the terms "setting," "installation," "connection," etc., should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] Example 1:

[0024] like Figure 1As shown, the vehicle refrigeration unit's heating and defrosting pipeline includes a refrigeration circuit, which is used to regulate the temperature inside the refrigerated compartment of the refrigerated vehicle or trailer. The refrigeration circuit includes a compressor 1, a condenser 4, and an evaporator 6. The compressor 1 is filled with a refrigerant such as Freon. The high-pressure steam outlet 101 of the compressor 1 is connected to pipe 8 and pipe 7 via a main pipeline. A one-way valve 14 is installed on the main pipeline. Pipe 8 is connected to the inlet of the condenser 4, and pipe 7 is connected to the inlet of the evaporator 6. A first expansion valve 5 is installed at the inlet of the evaporator 6. The first expansion valve 5 is used to throttle and cool the refrigerant entering the evaporator 6. A first solenoid valve 2 is installed on pipe 8. The first solenoid valve 2 is a normally open solenoid valve. A second solenoid valve 3 is installed on pipe 7. The second solenoid valve 3 is a normally closed solenoid valve. That is, the high-pressure steam outlet 101 of the compressor 1 is connected to the first solenoid valve 2 and the second solenoid valve 3 via the one-way valve 14. The outlet of the condenser 4 is connected to the first expansion valve 5, and the outlet of the evaporator 6 is connected to the low-temperature return steam outlet 102 of the compressor 1.

[0025] The working principle of this embodiment is as follows: Compressor 1 is connected to generator 13. During normal cooling, generator 13 starts compressor 1, which compresses the refrigerant into high-temperature, high-pressure refrigerant gas. Since the first solenoid valve 2 is a normally open solenoid valve and the second solenoid valve 3 is a normally closed solenoid valve, pipeline 2 7 is disconnected, while pipeline 1 8 is open. The refrigerant gas enters the condenser 4 through the high-pressure steam outlet 101 and pipeline 1 8 to exchange heat with the surrounding air. At this time, the refrigerant gas cools down and becomes medium-temperature, high-pressure liquid refrigerant. After the liquid refrigerant is throttled and cooled by the first expansion valve 5, it becomes low-temperature, low-pressure liquid and enters the evaporator 6. In the evaporator 6, it further exchanges heat with the surrounding air and absorbs heat from the air. At this time, the refrigerant temperature rises, achieving the cooling effect. Finally, the refrigerant returns to compressor 1 through the low-temperature return steam outlet 102 for recirculation.

[0026] When defrosting of evaporator 6 is required, the first solenoid valve 2 is closed and the second solenoid valve 3 is opened. The compressor 1 is started by generator 13 or external power supply. The high-temperature and high-pressure refrigerant gas enters pipeline 2 7 through high-pressure steam outlet 101 and flows to evaporator 6 to heat and defrost evaporator 6. During the heat exchange process of refrigerant, as the refrigerant and evaporator 6 continuously exchange heat, the superheat of refrigerant in low-pressure return steam pipeline changes continuously. By monitoring the superheat of refrigerant in low-pressure return steam pipeline in real time, refrigerant is replenished or reduced.

[0027] When the temperature of evaporator 6 is relatively high, the low-pressure system pressure between the outlet of evaporator 6 and compressor 1 will gradually increase, which may cause compressor 1 to operate under overload. At this time, in order to avoid the above situation, the first solenoid valve 2 is opened, so that some of the high-temperature and high-pressure refrigerant gas can enter the condenser 4 through pipe 8 for cooling and temporary storage, thereby reducing the amount of refrigerant entering the low-pressure system and thus reducing the low-pressure system pressure. This ensures that the high and low pressures of the compressor 1 system are controllable while maintaining heating and defrosting efficiency, ensuring that compressor 1 always operates within the ideal operating range and extending the service life of the refrigeration system.

[0028] Example 2:

[0029] like Figures 2 to 6 As shown, a vehicle refrigeration unit heating and defrosting pipeline includes a liquid storage tank 10, a dryer filter 11, and a plate heat exchanger 9 between a condenser 4 and an evaporator 6. The plate heat exchanger 9 has a first refrigerant circulation channel and a second refrigerant circulation channel. The outlet of the condenser 4 is connected to the liquid storage tank 10, and a one-way valve 801 is installed on the pipeline between the outlet of the condenser 4 and the liquid storage tank 10. The liquid storage tank 10 is connected to the dryer filter 11, and the dryer filter 11 is connected to the inlet of the second refrigerant circulation channel in the plate heat exchanger 9. The outlet of the second refrigerant circulation channel is connected to the first expansion valve 5 through a third solenoid valve 15. In this embodiment, both the second solenoid valve 3 and the first expansion valve 5 are connected to the evaporator 6 through a distributor 16. The distributor 16 is used to evenly distribute the refrigerant to each capillary tube in the evaporator 6. The second solenoid valve 3 is connected to the liquid storage tank 10 through a one-way valve 701. Among them, the liquid storage tank 10, the dryer filter 11, the plate heat exchanger 9 and the liquid distributor 16 are all existing technologies and are available on the market.

[0030] A fourth solenoid valve 12 and a second expansion valve 17 are installed on the pipeline between the dryer filter 11 and the first refrigerant circulation channel. The outlet of the dryer filter 11 is connected to the second expansion valve 17 through the fourth solenoid valve 12. The second expansion valve 17 is connected to the inlet of the first refrigerant circulation channel, and the outlet of the first refrigerant circulation channel is connected to the medium-temperature return steam port 103 of the condenser 4. This pipeline can pre-cool the compressor 1 on the one hand, and exchange heat with the main refrigeration pipeline on the other hand, thereby improving the refrigeration efficiency. Everything else is the same as in Embodiment 1.

[0031] The working principle of this embodiment:

[0032] During normal cooling, the second solenoid valve 3 is closed. The refrigerant circulation process in the main refrigeration pipeline is as follows: the compressor 1 compresses the refrigerant into a high-temperature, high-pressure gas. The high-temperature, high-pressure gas enters pipeline 8 through one-way valve 14 and the first solenoid valve 2. One-way valve 14 can prevent the high-temperature, high-pressure gas from flowing back. The high-temperature, high-pressure gas enters the condenser 4 through pipeline 8 for heat exchange and becomes medium-temperature, high-pressure refrigerant. Then, through one-way valve 801, the medium-temperature, high-pressure refrigerant enters the liquid receiver 10 and the dryer filter 11 in sequence to store and dry the refrigerant. Then, a portion of the refrigerant enters the second refrigerant circulation channel in the plate heat exchanger 9 for subcooling. After passing through the third solenoid valve 15, it enters the first expansion valve 5. The first expansion valve 5 throttles and cools the refrigerant. At this time, the refrigerant becomes a low-temperature, low-pressure liquid. After being evenly distributed through the distributor 16, it flows into the evaporator 6 to exchange heat with the air, absorbing heat from the air and completing the cooling effect. Finally, the refrigerant returns to the compressor 1 to continue compression and circulation.

[0033] At the same time, the fourth solenoid valve 12 is opened, and another part of the medium-temperature high-pressure refrigerant enters the second expansion valve 17 through the fourth solenoid valve 12. After being throttled and cooled by the second expansion valve 17, it becomes a low-temperature low-pressure liquid refrigerant. The refrigerant enters the first refrigerant circulation channel, which exchanges heat with the second refrigerant circulation channel in the plate heat exchanger 9. The refrigerant in the first refrigerant circulation channel absorbs heat and becomes a medium-temperature state. Finally, it returns to the compressor 1 through the medium-temperature return steam port 103. This passage exchanges heat on the main refrigeration pipeline on the one hand, and pre-cools the compressor 1 on the other hand, thereby improving the refrigeration efficiency and refrigeration effect, and protecting the compressor 1.

[0034] When defrosting of evaporator 6 is required, close the first solenoid valve 2, the third solenoid valve 15, and the fourth solenoid valve 12, and open the second solenoid valve 3. The defrosting process is the same as in Example 1. When defrosting evaporator 6 by heating, liquid can be added to the system by opening the third solenoid valve 15.

[0035] Whether during defrosting or normal cooling, this invention can achieve pressure balance at both ends of the third solenoid valve 15 when the third solenoid valve 15 in the main refrigeration pipeline is in the closed state, ensuring the normal and stable operation of the third solenoid valve 15 and avoiding the problem of system failure caused by pressure imbalance in the system.

[0036] Finally, although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A heating and defrosting pipeline for an automotive refrigeration unit, comprising a refrigeration circuit, characterized in that: The refrigeration circuit includes a compressor (1), a condenser (4) and an evaporator (6). The high-pressure steam outlet (101) of the compressor (1) is connected to the condenser (4) and the evaporator (6) through a first pipeline (8) and a second pipeline (7) respectively. A first solenoid valve (2) is provided on the first pipeline (8), and a second solenoid valve (3) is provided on the second pipeline (7). The outlet of the condenser (4) is connected to the first expansion valve (5), and the first expansion valve (5) is connected to the inlet of the evaporator (6). The outlet of the evaporator (6) is connected to the low-temperature return steam outlet (102) of the compressor (1).

2. The vehicle refrigeration unit heating and defrosting pipeline according to claim 1, characterized in that: The first solenoid valve (2) is a normally open solenoid valve, and the second solenoid valve (3) is a normally closed solenoid valve.

3. The vehicle refrigeration unit heating and defrosting pipeline according to claim 2, characterized in that: It also includes a liquid storage tank (10), a dryer filter (11) and a plate heat exchanger (9). The plate heat exchanger (9) is provided with a first refrigerant circulation channel and a second refrigerant circulation channel. The outlet of the condenser (4) is connected to the liquid storage tank (10). The liquid storage tank (10) is connected to the dryer filter (11). The dryer filter (11) is connected to the second refrigerant circulation channel. The outlet of the second refrigerant circulation channel is connected to the first expansion valve (5) through a third solenoid valve (15). The first expansion valve (5) is connected to the evaporator (6) through a distributor head (16).

4. The vehicle refrigeration unit heating and defrosting pipeline according to claim 3, characterized in that: It also includes a fourth solenoid valve (12) and a second expansion valve (17). The outlet of the dryer filter (11) is connected to the second expansion valve (17) through the fourth solenoid valve (12). The second expansion valve (17) is connected to the inlet of the first refrigerant circulation channel. The outlet of the first refrigerant circulation channel is connected to the medium-temperature return steam port (103) of the condenser (4).

5. The automotive refrigeration unit heating and defrosting pipeline according to claim 4, characterized in that: The second solenoid valve (3) is connected to the liquid storage tank (10) through the one-way valve three (701), and the one-way valve two (801) is provided between the outlet of the condenser (4) and the liquid storage tank (10).

6. The vehicle refrigeration unit heating and defrosting pipeline according to any one of claims 1 to 5, characterized in that: The high-pressure steam outlet (101) of the compressor (1) is connected to the first solenoid valve (2) and the second solenoid valve (3) respectively through the one-way valve (14).

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