A refrigeration system and its anti-liquid-return control method

Abstract

The present invention discloses a refrigeration system and its anti-liquid-return control method. In this system, the first path at the outlet end of the liquid storage tank is connected to the inlet end of the throttling device through a first one-way valve, and the second path is connected to the inlet end of the throttling device through a refrigerant pump; the outlet end of the throttling device is connected to the inlet end of the gas-liquid separation elbow through an evaporator. The inlet end and the first outlet end of the three-way pipe are arranged along the outlet end direction of the gas-liquid separation elbow. The outlet end of the gas-liquid separation elbow is connected to the inlet end of the second one-way valve through the inlet end and the first outlet end of the three-way pipe; the second outlet end of the three-way pipe is located inside the gas-liquid separation elbow and is connected to the inlet end of the liquid storage pipe; the outlet end of the liquid storage pipe is connected to the inlet end of the compressor through a liquid resistance pipe; the first path at the inlet end of the condenser is connected to the outlet end of the second one-way valve, and the second path is connected to the outlet end of the compressor; the outlet end of the condenser is connected to the inlet end of the liquid storage tank. The present invention solves the problem of the compressor being liquid-carrying in the pump mode.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorine pump air conditioners, and particularly to a refrigeration system and a liquid backflow prevention control method thereof. Background Art

[0002] When the outdoor temperature is relatively low in winter, a variable-frequency fluorine pump air conditioner utilizes the outdoor natural cold source to start the pump mode, and uses a refrigerant pump to circulate the indoor and outdoor refrigerant, so as to achieve the purpose of cold quantity transportation. When the outdoor temperature is relatively high in summer, the compressor mode is started. Since the power consumed by the refrigerant pump is much lower than that consumed by the compressor, this product can achieve a good energy-saving purpose. However, during the operation of the pump mode of this product, the compressor is prone to liquid carry-over. When switching from the pump mode to the compressor mode, it may cause the compressor to start with liquid carry-over, resulting in damage to the compressor. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a refrigeration system and a liquid backflow prevention control method thereof for at least one defect existing in the related technologies mentioned in the above background art: during the operation of the pump mode, the compressor is prone to liquid carry-over, and when switching from the pump mode to the compressor mode, it may cause the compressor to start with liquid carry-over, resulting in damage to the compressor.

[0004] The technical solution adopted by the present invention to solve its technical problem is to construct a refrigeration system, including a liquid storage tank, a first one-way valve, a refrigerant pump, a throttling device, an evaporator, a compressor, a second one-way valve, a condenser, and a liquid backflow prevention pipeline;

[0005] The liquid backflow prevention pipeline includes a gas-liquid separation elbow for separating gas-liquid refrigerant by centrifugal force, a three-way pipe, a liquid storage pipe for temporarily storing liquid refrigerant, and a liquid resistance pipe for preventing liquid refrigerant from flowing to the compressor;

[0006] The first path at the outlet end of the liquid storage tank is connected to the inlet end of the throttling device through the first one-way valve, and the second path is connected to the inlet end of the throttling device through the refrigerant pump;

[0007] The outlet end of the throttling device is connected to the inlet end of the gas-liquid separation elbow through the evaporator. The inlet end and the first outlet end of the three-way pipe are arranged along the outlet end direction of the gas-liquid separation elbow. The outlet end of the gas-liquid separation elbow is connected to the inlet end of the second one-way valve through the inlet end and the first outlet end of the three-way pipe;

[0008] The second outlet end of the three-way pipe is located inside the gas-liquid separation elbow and is connected to the inlet end of the liquid storage pipe; the outlet end of the liquid storage pipe is connected to the inlet end of the compressor through the liquid resistance pipe;

[0009] The first path at the inlet end of the condenser is connected to the outlet end of the second one-way valve, and the second path is connected to the outlet end of the compressor; the outlet end of the condenser is connected to the inlet end of the liquid storage tank.

[0010] Preferably, in the refrigeration system of the present invention, the gas-liquid separation elbow is an L-shaped pipe.

[0011] Preferably, in the refrigeration system of the present invention, the liquid storage pipe is a bent pipe.

[0012] Preferably, in the refrigeration system of the present invention, the liquid storage pipe is a U-shaped pipe.

[0013] Preferably, in the refrigeration system of the present invention, the liquid resistance pipe is a straight pipe arranged along the direction of gravity.

[0014] Preferably, in the refrigeration system of the present invention, the refrigeration system further includes a temperature sensor and a pressure sensor provided at the outlet end of the evaporator.

[0015] Preferably, in the refrigeration system of the present invention, the refrigeration system further includes an electric heating system on the return air side before or after the evaporator for heating the air.

[0016] Preferably, in the refrigeration system of the present invention, the refrigeration system further includes an auxiliary heater provided at the bottom of the compressor.

[0017] The present invention also constructs a method for preventing liquid backflow control of the refrigeration system described above, including the following steps:

[0018] When the superheat degree at the outlet end of the evaporator detected by the temperature sensor < X, it is judged whether the opening degree of the throttling device is the minimum opening degree Y. If not, the opening degree of the throttling device is adjusted smaller until the outlet superheat degree X that meets the set requirements is satisfied; if so, the electric heating system and the auxiliary heater are turned on for heat compensation to prevent liquid refrigerant from entering the compressor.

[0019] When the superheat degree at the outlet end of the evaporator detected by the temperature sensor ≥ X, if the electric heating system and the auxiliary heater are turned on, first turn off the electric heating system, and then judge whether the opening degree of the throttling device is greater than the minimum opening degree Y. If so, then turn off the auxiliary heater; if not, do not process.

[0020] When the superheat degree at the outlet section of the evaporator detected by the temperature sensor ≥ X, if the electric heating system and the auxiliary heater are not turned on, the opening degree of the throttling device is adjusted larger until the outlet superheat degree X that meets the set requirements is satisfied.

[0021] Preferably, in the anti-liquid return control method of the refrigeration system of the present invention, when the superheat degree at the outlet section of the evaporator detected by the temperature sensor ≥ X, it includes:

[0022] When the superheat degree at the outlet of the evaporator detected by the temperature sensor ≥ X + a, where a is the superheat degree hysteresis;

[0023] Judging whether the opening degree of the throttling device is greater than the minimum opening degree Y includes:

[0024] Judging whether the opening degree of the throttling device is greater than the minimum opening degree Y + b, where b is the opening degree hysteresis.

[0025] By implementing the present invention, the following beneficial effects are achieved:

[0026] The present invention solves the problem of liquid carry - over of the compressor in the pump mode, prevents the compressor from being damaged due to liquid - carry - over start - up during the process of switching the compressor in the pump mode, and prolongs the service life of the compressor. Description of the Drawings

[0027] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0028] Figure 1 is a schematic diagram of the refrigeration system of the present invention;

[0029] Figure 2 is a schematic flow diagram of the anti - liquid return control method of the refrigeration system of the present invention. Detailed Embodiments

[0030] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the drawings.

[0031] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0033] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a chemical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0034] As Figure 1 shown, an embodiment of the present invention discloses a refrigeration system, including a liquid storage tank 1, a first one-way valve 2, a refrigerant pump 3, a throttling device 4, an evaporator 5, a compressor 6, a second one-way valve 7, a condenser 8, and a liquid backflow prevention pipeline 9. For example, the throttling device 4 is an electronic expansion valve.

[0035] Among them, the liquid backflow prevention pipeline 9 includes a gas-liquid separation elbow ab for separating gas-liquid refrigerant by centrifugal force, a three-way pipe bfc, a liquid storage pipe cde for temporarily storing liquid refrigerant, and a liquid resistance pipe de for preventing liquid refrigerant from flowing to the compressor 6.

[0036] Specifically, the first path at the outlet end of the liquid storage tank 1 is connected to the inlet end of the throttling device 4 through the first one-way valve 2, and the second path is connected to the inlet end of the throttling device 4 through the refrigerant pump 3;

[0037] The outlet end of the throttling device 4 is connected to the inlet end of the gas-liquid separation elbow ab through the evaporator 5. The inlet end and the first outlet end of the three-way pipe bfc are arranged along the outlet end direction of the gas-liquid separation elbow ab. The outlet end of the gas-liquid separation elbow ab is connected to the inlet end of the second one-way valve 7 through the inlet end and the first outlet end of the three-way pipe bfc;

[0038] The second outlet end of the three-way pipe bfc is located inside the gas-liquid separation elbow ab and is connected to the inlet end of the liquid storage pipe cde; the outlet end of the liquid storage pipe cde is connected to the inlet end of the compressor 6 through the liquid resistance pipe de;

[0039] The first path at the inlet end of the condenser 8 is connected to the outlet end of the second one-way valve 7, and the second path is connected to the outlet end of the compressor 6; the outlet end of the condenser 8 is connected to the inlet end of the liquid storage tank 1.

[0040] In this embodiment, the gas-liquid separation elbow ab is an L-shaped pipe. The liquid storage pipe cde is a bent pipe, and preferably a U-shaped pipe. The liquid resistance pipe de is a straight pipe arranged along the gravity direction.

[0041] Specifically, as Figure 1As shown in the figure, the design of the anti-liquid-return pipeline 9 prevents liquid refrigerant from entering the compressor 6 in the physical channel. If the refrigerant at point a of the pipeline is liquid-carrying, when the refrigerant passes through the bend of ab, due to the large density of the liquid refrigerant, when it reaches point b of the pipeline after passing the bend, under the action of centrifugal force, the liquid refrigerant will flow close to the outer wall of the pipeline towards the f end. In this way, there is basically no liquid refrigerant at the c outlet of the tee at point b, and it is basically gaseous refrigerant. Moreover, in the pump mode, the compressor 6 is not working, and the pipeline section bcde is blocked.

[0042] The cde section is a U-shaped upward bend pipe, which can temporarily store a small amount of liquid refrigerant to prevent emergencies. In the de section, since the liquid refrigerant needs to overcome a large resistance to flow upward under the action of gravity, so if the liquid refrigerant wants to reach the compressor 6, it will basically vaporize. Therefore, the de section can further prevent the liquid refrigerant from returning to the compressor 6.

[0043] In addition, it is possible to prevent liquid refrigerant from entering the compressor 6 from the control logic. Therefore, the refrigeration system also includes a temperature sensor 10 and a pressure sensor 11 provided at the outlet end of the evaporator 5. The refrigeration system also includes an electric heating system (not shown) on the return air side before or after the evaporator 5 for heating the air. The refrigeration system also includes an auxiliary heater (not shown) provided at the bottom of the compressor 6.

[0044] Correspondingly, as Figure 2 shown, an embodiment of the present invention discloses an anti-liquid-return control method for a refrigeration system, including the following steps:

[0045] When the superheat degree at the outlet end of the evaporator 5 detected by the temperature sensor 10 < X, it is judged whether the throttle device 4 is at the minimum opening Y. If not, the opening of the throttle device 4 is adjusted smaller until the outlet superheat degree X that meets the set requirements is reached; if so, the electric heating system and the auxiliary heater are turned on for heat compensation to achieve that no liquid refrigerant enters the compressor 6;

[0046] When the superheat degree at the outlet end of the evaporator 5 detected by the temperature sensor 10 ≥ X, if the electric heating system and the auxiliary heater are turned on, first turn off the electric heating system, and then judge whether the opening of the throttle device 4 is greater than the minimum opening Y. If so, then turn off the auxiliary heater; if not, do not process;

[0047] When the superheat degree at the outlet section of the evaporator 5 detected by the temperature sensor 10 ≥ X, if the electric heating system and the auxiliary heater are not turned on, the opening of the throttle device 4 is adjusted larger until the outlet superheat degree X that meets the set requirements is reached.

[0048] Preferably, to avoid frequent start and stop of the electric heating system and the auxiliary heater, when the superheat degree at the outlet section of the evaporator 5 detected by the temperature sensor 10 is ≥ X, it includes: when the superheat degree at the outlet of the evaporator 5 detected by the temperature sensor 10 is ≥ X + a, where a is the superheat degree hysteresis, used to provide a stable range for the superheat degree.

[0049] Judging whether the opening degree of the throttling device 4 is greater than the minimum opening degree Y includes: judging whether the opening degree of the throttling device 4 is greater than the minimum opening degree Y + b, where b is the opening degree hysteresis, used to provide a stable range for the opening degree.

[0050] An embodiment of the present invention also discloses a refrigeration device, including the refrigeration system and the control system described in the above embodiment, and the refrigeration system will not be described in detail here. Among them, the control system is electrically connected to the first one-way valve 2, the refrigerant pump 3, the throttling device 4, the evaporator 5, the compressor 6, the second one-way valve 7, the condenser 8, the electric heating system and the auxiliary heater.

[0051] By implementing the present invention, the following beneficial effects are achieved:

[0052] The present invention solves the problem of liquid carry - over of the compressor in the pump mode, prevents the liquid carry - over start of the compressor during the process of switching the compressor in the pump mode, and damages the compressor, and prolongs the service life of the compressor.

[0053] It can be understood that the above - mentioned embodiments only represent some implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, the above - mentioned embodiments or technical features can be freely combined, and several deformations and improvements can also be made. These all belong to the protection scope of the present invention, that is, the embodiments described in "in some embodiments" can be freely combined with any of the above - mentioned embodiments. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention should fall within the scope covered by the claims of the present invention.

Claims

1. A method for preventing liquid backflow control of a refrigeration system, characterized in that, The refrigeration system includes a liquid storage tank (1), a first one-way valve (2), a refrigerant pump (3), a throttling device (4), an evaporator (5), a compressor (6), a second one-way valve (7), a condenser (8), a liquid backflow prevention pipeline (9), a temperature sensor (10) and a pressure sensor (11) provided at the outlet end of the evaporator (5), an electric heating system on the return air side for heating air provided before or after the evaporator (5), and an auxiliary heater provided at the bottom of the compressor (6); The liquid backflow prevention pipeline (9) includes a gas-liquid separation elbow for separating gas-liquid refrigerant by centrifugal force, a three-way pipe, a liquid storage pipe for temporarily storing liquid refrigerant, and a liquid resistance pipe for preventing liquid refrigerant from flowing to the compressor (6); The first path at the outlet end of the liquid storage tank (1) is connected to the inlet end of the throttling device (4) through the first one-way valve (2), and the second path is connected to the inlet end of the throttling device (4) through the refrigerant pump (3); The outlet end of the throttling device (4) is connected to the inlet end of the gas-liquid separation elbow through the evaporator (5). The inlet end and the first outlet end of the three-way pipe are arranged along the outlet end direction of the gas-liquid separation elbow. The outlet end of the gas-liquid separation elbow is connected to the inlet end of the second one-way valve (7) through the inlet end and the first outlet end of the three-way pipe; The second outlet end of the three-way pipe is located inside the gas-liquid separation elbow and is connected to the inlet end of the liquid storage pipe; the outlet end of the liquid storage pipe is connected to the inlet end of the compressor (6) through the liquid resistance pipe; The first path at the inlet end of the condenser (8) is connected to the outlet end of the second one-way valve (7), and the second path is connected to the outlet end of the compressor (6); the outlet end of the condenser (8) is connected to the inlet end of the liquid storage tank (1); The liquid backflow prevention control method of the refrigeration system includes the following steps: When the superheat degree at the outlet end of the evaporator (5) detected by the temperature sensor (10) < X, it is judged whether the throttling device (4) is at the minimum opening degree Y. If not, the opening degree of the throttling device (4) is adjusted smaller until the outlet superheat degree X that meets the set requirements is achieved; if so, the electric heating system and the auxiliary heater are turned on for heat compensation to prevent liquid refrigerant from entering the compressor (6); When the superheat degree at the outlet end of the evaporator (5) detected by the temperature sensor (10) ≥ X, if the electric heating system and the auxiliary heater are turned on, first turn off the electric heating system, and then judge whether the opening degree of the throttling device (4) is greater than the minimum opening degree Y. If so, then turn off the auxiliary heater; if not, no processing is performed; When the superheat degree at the outlet section of the evaporator (5) detected by the temperature sensor (10) ≥ X, if the electric heating system and the auxiliary heater are not turned on, the opening degree of the throttling device (4) is adjusted larger until the outlet superheat degree X that meets the set requirements is achieved.

2. The anti-liquid-return control method of the refrigeration system according to claim 1, characterized in that, The situation where the superheat degree at the outlet section of the evaporator (5) detected by the temperature sensor (10) ≥ X includes: When the superheat degree at the outlet of the evaporator (5) detected by the temperature sensor (10) is ≥ X + a, where a is the superheat degree hysteresis; Judging whether the opening degree of the throttling device (4) is greater than the minimum opening degree Y includes: Judging whether the opening degree of the throttling device (4) is greater than the minimum opening degree Y + b, where b is the opening degree hysteresis.

3. The anti-liquid-return control method of the refrigeration system according to claim 1, wherein The gas-liquid separation elbow is an L-shaped pipe.

4. The anti-liquid return control method of the refrigeration system according to claim 1, characterized in that, The liquid storage pipe is an elbow pipe.

5. The anti-liquid return control method of the refrigeration system according to claim 4, characterized in that, The liquid storage pipe is a U-shaped pipe.

6. The anti-liquid return control method of the refrigeration system according to claim 1, characterized in that, The liquid resistance pipe is a straight pipe arranged along the gravity direction.

Images