Novel liquid homogenizing device for evaporator

Abstract

The utility model discloses a novel liquid homogenizing device for an evaporator, and relates to the technical field of evaporators. The novel liquid homogenizing device for the evaporator comprises the evaporator, an air outlet is formed in the top of the evaporator, a liquid homogenizing device is welded to the inner wall of the evaporator, a liquid inlet pipe is arranged at the top of the liquid homogenizing device, and the liquid inlet pipe communicates with an expansion valve through a pipeline; the liquid uniformizing device comprises a distribution head, a distribution pipe, a liquid uniformizing pipe and a mounting plate. According to the novel liquid equalizing device for the evaporator, load management is carried out on a unit according to the actual load of a whole air conditioning system, and the situation that a compressor carries liquid and cannot return oil due to compressor oil deficiency caused by air conditioning load changes is avoided; false alarm and false start and stop caused by unit load jump are avoided, heat exchanger pipe drying can be caused by too small expansion valve opening, liquid carrying caused by incomplete evaporation can be caused by too large expansion valve opening, and suction liquid carrying is reduced while superheat degree control is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of evaporators, in particular to a novel liquid equalizing device for evaporators. Background Art

[0002] The falling film distribution device is set at the liquid inlet of the falling film evaporator. Its main purpose is to allow the supercooled refrigerant liquid from the condenser to drip evenly on the heat exchange tube inside the evaporator. The refrigerant is evenly distributed on the surface of the heat exchange tube of the evaporator to form a liquid film for evaporation. This type of evaporator has the advantages of high heat transfer efficiency and small refrigerant charge, so it has become a hot research object in the refrigeration and air-conditioning industry in recent years.

[0003] Usually, the refrigerant entering the evaporator is in the state of gas and liquid. The uniformity of the refrigerant dripping between the heat exchange tubes of the evaporator directly affects the performance of the evaporator and the performance of the unit. If the two-phase refrigerant is not evenly distributed on the heat exchange tubes of the evaporator, the overall heat transfer performance of the evaporator will decrease.

[0004] Not only does the structure of the liquid balancing device affect the performance of the evaporator, but its control method also directly affects the performance of the unit. Because the liquid inlet volume of the device directly affects the liquid balancing effect of the device, if the liquid volume is too large and the pressure difference is too large, although the liquid is evenly distributed, the excessive pressure drop will affect the evaporation performance and unit performance of the unit. If the liquid volume is too small and the pressure difference is too small, the gas-liquid two-phase liquid will be concentrated in a certain area of ​​the evaporator, resulting in no liquid heat exchange in some heat exchange tubes of the evaporator, resulting in dry pipes; in view of this, we proposed a new type of liquid balancing device for evaporators. Utility Model Content

[0005] In view of the deficiencies of the prior art, the utility model provides a novel liquid equalizing device for an evaporator, which solves the problems mentioned in the above background technology.

[0006] To achieve the above objectives, the utility model is implemented through the following technical solutions: a new type of liquid equalizing device for an evaporator, comprising an evaporator, a gas outlet is provided on the top of the evaporator, a liquid equalizing device is welded on the inner wall of the evaporator, a liquid inlet pipe is provided on the top of the liquid equalizing device, and the liquid inlet pipe is connected to the expansion valve through a pipeline, and the liquid equalizing device comprises:

[0007] A distribution head, wherein the distribution head is connected to the liquid inlet pipe, and the bottom of the distribution head is connected to one end of the distribution pipe;

[0008] The other end of the distribution pipe is connected to the liquid balancing pipe, and mounting plates are welded on both sides of the liquid balancing pipe, and the mounting plates are fixed to the side walls of the evaporator.

[0009] Optionally, a liquid baffle is fixed at the bottom of the liquid balancing device, and a heat exchange tube is arranged at the bottom of the liquid balancing device.

[0010] Optionally, a pressure sensor is passed through and fixed on the side wall of the air outlet, a temperature sensor is arranged below the pressure sensor, the temperature sensor is detachably mounted on the side wall of the air outlet, and a detection end of the temperature sensor is located inside the air outlet.

[0011] Optionally, a pressure difference control valve is connected between the liquid inlet pipe and the evaporator through a pipeline, and the pressure difference control valve is located outside the evaporator.

[0012] Optionally, the bottom of the evaporator is connected to a liquid level control device.

[0013] A novel control logic for a liquid equalizing device for an evaporator, the control logic comprising the following methods:

[0014] a. Liquid level sensor detects the liquid level in the evaporator;

[0015] b. If the liquid level does not reach the set range, the system will determine whether the unit superheat meets the requirements. If so, it will determine whether the pressure difference of the liquid equalization device meets the requirements. If so, the unit will maintain the status and continue to operate;

[0016] c. Liquid level controller is the priority judgment standard.

[0017] d. If the system fluctuates greatly, only whether the unit liquid level is within a reasonable range is determined; superheat and pressure difference are important judgment bases in stable control and can be used as part of fine control; fine control can achieve the highest energy efficiency and stable operation of the unit.

[0018] Optionally, the step a further comprises:

[0019] If the liquid level exceeds the set value, the control unit will issue an instruction to let the expansion valve controller close the expansion valve at a certain speed. If the liquid level is lower than the set value, the control unit will issue an instruction to let the expansion valve controller open the expansion valve at a certain speed.

[0020] Optionally, the step b further comprises:

[0021] If the liquid level does not reach the set range value, the system will determine whether the unit superheat value meets the requirements. If it does not meet the requirements, the controller will issue an instruction to open or close the expansion valve until the conditions are met.

[0022] Optionally, step c further includes:

[0023] If the liquid level is within the control range, it is necessary to determine the size of the average pressure difference. If the pressure difference is large, it means that the liquid flow of the unit is too large. If the pressure difference is within a reasonable range, it is maintained;

[0024] If the pressure difference exceeds the reasonable range, the expansion valve needs to reduce the expansion valve opening at a certain speed. If the pressure difference is too small, it means that the incoming liquid flow is too small. If the pressure difference is within a reasonable range, then maintain it. If the pressure difference is less than the reasonable range, then the expansion valve opens at a certain speed.

[0025] The utility model provides a novel liquid equalizing device for an evaporator, which has the following beneficial effects:

[0026] (1) This new type of liquid equalizing device for the evaporator manages the load of the unit according to the actual load of the entire air-conditioning system. It will not cause the compressor to carry liquid or the compressor oil to be missing and unable to return oil due to changes in the air-conditioning load. It will not cause false alarms and false starts and shutdowns due to unit load jumps. If the expansion valve opening is too small, it will cause the heat exchanger to dry out. If it is too large, it will cause incomplete evaporation and carry liquid. Superheat control also reduces the suction liquid.

[0027] (2) This new type of liquid equalizing device for the evaporator, liquid level control combined with electronic expansion valve control can more quickly adjust the amount of refrigerant required by the system, thereby quickly balancing the load of the unit condenser and evaporator; liquid level control plus superheat control is a secondary refined control. When the liquid level control fails, the superheat control can compensate for the problems caused by the liquid level control, such as liquid in the compressor suction and untimely oil return.

[0028] (3) The new type of liquid equalizing device used in the evaporator, based on the above precise control, evenly distributes the liquid from the condenser to the evaporator heat exchange tubes, thereby greatly improving the utilization rate of the heat exchange tubes and preventing the dry tubes or local liquid from being too large and not completely evaporated. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the overall device of the utility model;

[0030] Figure 2 It is a structural schematic diagram of the liquid equalizing device of the utility model.

[0031] In the figure: 1. expansion valve; 2. evaporator; 3. liquid equalizing device; 31. distribution head; 32. distribution pipe; 33. liquid equalizing pipe; 34. mounting plate; 4. liquid inlet pipe; 5. air outlet; 6. liquid baffle plate; 7. heat exchange tube; 8. pressure sensor; 9. temperature sensor; 10. differential pressure control valve; 11. liquid level control device. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] See also Figure 1-Figure 2 The utility model provides a technical solution: a new type of liquid equalizing device for an evaporator, comprising an evaporator 2, an air outlet 5 is provided at the top of the evaporator 2, a liquid equalizing device 3 is welded on the inner wall of the evaporator 2, a liquid inlet pipe 4 is provided at the top of the liquid equalizing device 3, and the liquid inlet pipe 4 is connected to the expansion valve 1 through a pipeline, and the liquid equalizing device 3 comprises:

[0034] The distribution head 31 is used for liquid distribution. The distribution head 31 is connected to the liquid inlet pipe 4, and the bottom of the distribution head 31 is connected to one end of the distribution pipe 32;

[0035] The other end of the distribution pipe 32 is connected to the liquid balancing pipe 33 , and mounting plates 34 are welded on both sides of the liquid balancing pipe 33 , and the mounting plates 34 are fixed to the side walls of the evaporator 2 .

[0036] A liquid baffle 6 is fixed at the bottom of the liquid balancing device 3 , and a heat exchange tube 7 is arranged at the bottom of the liquid balancing device 3 . The heat exchange tube 7 is used for heat exchange.

[0037] Based on the above precise control, this liquid equalizing device evenly distributes the liquid from the condenser to the evaporator heat exchange tubes, which greatly improves the utilization rate of the heat exchange tubes and prevents the dry tubes or local liquid from being too large and not completely evaporated.

[0038] A pressure sensor 8 is passed through and fixed on the side wall of the gas outlet 5, and a temperature sensor 9 is arranged below the pressure sensor 8. The temperature sensor 9 is detachably mounted on the side wall of the gas outlet 5, and the detection end of the temperature sensor 9 is located inside the gas outlet 5. A pressure differential control valve 10 is connected between the liquid inlet pipe 4 and the evaporator 2 through a pipeline, and the pressure differential control valve 10 is located outside the evaporator 2.

[0039] The bottom of the evaporator 2 is connected to a liquid level control device 11. According to the actual load of the entire air-conditioning system, the load management of the unit is carried out, and the compressor will not be liquid-carrying or the compressor oil will not be missing and unable to return oil due to changes in the air-conditioning load; there will be no false alarms, false starts and shutdowns caused by unit load jumps, and the expansion valve opening will be too small to cause the heat exchanger dry pipe, and too large to cause incomplete evaporation and liquid-carrying. Superheat control also reduces the suction liquid. Liquid level control combined with electronic expansion valve control can more quickly adjust the amount of refrigerant required by the system, thereby quickly balancing the unit condenser and evaporator loads; liquid level control plus superheat control is a secondary refined control. When liquid level control fails, superheat control can make up for the problems of compressor suction liquid and untimely oil return caused by liquid level control.

[0040] A new type of liquid equalizing device for evaporator, the control logic includes the following methods:

[0041] a. The liquid level sensor detects the liquid level in the evaporator. If the liquid level exceeds the set value, the control unit will issue an instruction to let the expansion valve controller close the expansion valve 1 at a certain speed. If the liquid level is lower than the set value, the control unit will issue an instruction to let the expansion valve controller open the expansion valve 1 at a certain speed.

[0042] b. If the liquid level does not reach the set range, the system will determine whether the unit superheat meets the requirements. If it does, the system will determine whether the pressure difference of the liquid equalization device meets the requirements. If it does, the unit will continue to operate. If the liquid level does not reach the set range, the system will determine whether the unit superheat meets the requirements. If it does not, the controller will issue an instruction to open or close the expansion valve 1 until the conditions are met.

[0043] c. The liquid level controller is the priority judgment standard. If the liquid level is within the control range, it is necessary to determine the size of the average pressure difference. If the pressure difference is large, it means that the liquid flow of the unit is too large. If the pressure difference is within a reasonable range, it is maintained;

[0044] If the pressure difference exceeds the reasonable range, the expansion valve 1 needs to reduce the expansion valve opening at a certain speed. If the pressure difference is too small, it means that the incoming liquid flow is too small. If the pressure difference is within a reasonable range, then maintain it. If the pressure difference is less than the reasonable range, then the expansion valve 1 increases the expansion valve opening at a certain speed.

[0045] d. If the system fluctuates greatly, only whether the unit liquid level is within a reasonable range is determined; superheat and pressure difference are important judgment bases in stable control and can be used as part of fine control; fine control can achieve the highest energy efficiency and stable operation of the unit.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new type of liquid equalizing device for evaporator, characterized by: The invention comprises an evaporator (2), wherein a gas outlet (5) is provided at the top of the evaporator (2), a liquid equalizing device (3) is welded on the inner wall of the evaporator (2), a liquid inlet pipe (4) is provided at the top of the liquid equalizing device (3), and the liquid inlet pipe (4) is connected to the expansion valve (1) through a pipeline, and the liquid equalizing device (3) comprises: A distribution head (31), the distribution head (31) is connected to the liquid inlet pipe (4), and the bottom of the distribution head (31) is connected to one end of the distribution pipe (32); A liquid balancing pipe (33), the other end of the distribution pipe (32) is connected to the liquid balancing pipe (33), and mounting plates (34) are welded on both sides of the liquid balancing pipe (33), and the mounting plates (34) are fixed to the side walls of the evaporator (2).

2. A novel liquid equalizing device for an evaporator according to claim 1, characterized in that: A liquid baffle (6) is fixed at the bottom of the liquid balancing device (3), and a heat exchange tube (7) is arranged at the bottom of the liquid balancing device (3).

3. A novel liquid equalizing device for an evaporator according to claim 1, characterized in that: A pressure sensor (8) is passed through and fixed on the side wall of the air outlet (5), a temperature sensor (9) is arranged below the pressure sensor (8), the temperature sensor (9) is detachably mounted on the side wall of the air outlet (5), and a detection end of the temperature sensor (9) is located inside the air outlet (5).

4. The novel liquid equalizing device for evaporator according to claim 1 is characterized in that: A pressure difference control valve (10) is connected between the liquid inlet pipe (4) and the evaporator (2) via a pipeline, and the pressure difference control valve (10) is located outside the evaporator (2).

5. The novel liquid equalizing device for evaporator according to claim 1 is characterized in that: The bottom of the evaporator (2) is connected to a liquid level control device (11).

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