Liquid distributor, heat exchanger assembly and control method thereof, and air conditioning system

Abstract

The present invention discloses a liquid distributor, a heat exchanger assembly, a control method thereof, and an air conditioning system. The liquid distributor includes: a liquid distributor head, a plurality of throttling branches connected to the liquid distributor head, each throttling branch including a plurality of throttling branches connected in parallel with each other and having different flow lengths, and a control valve arranged at the inlet of each throttling branch. The structure of the present invention is simple and reliable, with strong adaptability, and can effectively solve the problem of uneven refrigeration, defrosting, etc., and can also identify evaporator flow paths with uneven liquid distribution and uneven temperature in conjunction with a temperature sensor, and automatically adjust the liquid distribution capillary lengths of these flow paths, so as to achieve the purpose of uniform liquid distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid distributors, and in particular to a liquid distributor, a heat exchanger component using the liquid distributor, and a control method thereof. Background Art

[0002] As one of the four major components of compression refrigeration, the evaporator is responsible for handling the cold, hot and wet loads in the air conditioning system. The fin heat exchanger is a common evaporator and is widely used because of its simple structure and good heat exchange. Most commercial refrigeration fin evaporators are large in size and have many flow paths. In addition, the changes in the cross-section of the air duct often lead to uneven distribution of refrigerant in each flow path and uneven air supply speed, which in turn leads to large temperature differences between each flow path of the evaporator, low heat exchange efficiency, affecting the performance of the whole machine, and may even cause the evaporator to freeze and crack; on the other hand, it makes the frosting and defrosting uneven, causing local defrosting difficulties. In the case of structural limitations, the most commonly used method is to equip the evaporator with liquid separation capillaries of different lengths to adjust the problem of uneven liquid separation.

[0003] However, once the evaporator structure or system parameters change, the temperature of different flow paths will change immediately. At this time, the capillaries need to be re-matched, especially for refrigeration systems with multiple evaporators in series. If any of the previous evaporator parameters change, the liquid separation capillaries of all systems need to be re-matched, which is time-consuming and labor-intensive.

[0004] In the prior art, a patent with publication number CN 107062713 B discloses a liquid separation component and an air conditioner thereof, which controls uneven liquid separation by setting a gas-liquid separator at the liquid collecting port and controlling the gas-liquid mixing ratio entering the liquid separation pipe of the heat exchanger. However, this method is only applicable to small units with few liquid separation flow paths, and multiple gas-liquid separators need to be set up, which takes up a lot of space and has obvious disadvantages in terms of reliability and cost.

[0005] In the prior art, the existing patent with publication number CN 101694361 A discloses a liquid equalizing mechanism for a dry evaporator of a refrigeration system, which avoids the problem of uneven liquid separation by installing a liquid equalizing mechanism between the liquid inlet on the tube box side of the evaporator and the heat exchange tube. This method can only adjust the liquid separation amount, but cannot ensure uniform liquid separation temperature, and has poor adaptability. If the evaporator parameters or the environment change, the liquid separation structure cannot achieve the desired effect.

[0006] Therefore, how to provide a liquid distributor so that the length of the refrigerant flowing through each throttling branch can be adjusted, so that the temperature of each liquid distribution pipeline can be adjusted is a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0007] In order to solve the technical problem in the prior art that the temperature in each throttling branch of a liquid distributor cannot be adjusted individually, the present invention proposes a liquid distributor, a heat exchanger assembly and a control method thereof, and an air conditioning system.

[0008] The liquid distributor proposed in the present invention comprises: a liquid distributor head, a plurality of throttling branches connected to the liquid distributor head, each throttling branch comprising a plurality of throttling branches connected in parallel with each other and having different flow lengths, and a control valve arranged at the inlet of each throttling branch.

[0009] Furthermore, the throttling branch includes at least one throttling branch wound into a spiral tube shape having at least one flow ring.

[0010] Furthermore, the throttling branch includes two throttling branches, one of which is the spiral tube-shaped throttling branch, and the other throttling branch is a straight tube branch.

[0011] Furthermore, the process of the throttling branch includes three levels of processes, from top to bottom: a first level process of opening the spiral tubular throttling branch and closing the straight pipe branch, a second level process of opening the spiral tubular throttling branch and the straight pipe branch, and a third level process of opening the straight pipe branch and closing the spiral tubular throttling branch.

[0012] Furthermore, the throttling branch is a capillary tube.

[0013] Furthermore, the control valve is a solenoid valve.

[0014] The heat exchanger assembly proposed in the present invention includes a heat exchanger, connecting pipes connected one by one to the outlet ends of each heat exchange tube of the heat exchanger, a collecting pipe that collects the refrigerant in the connecting pipes, and a liquid distributor of the above technical solution, wherein the throttling branch of the liquid distributor is connected one by one to the inlet ends of each heat exchange tube of the heat exchanger.

[0015] Furthermore, it also includes a temperature sensing device; each of the temperature sensing devices detects the refrigerant temperature at the outlet end of a group of heat exchange tubes.

[0016] Further, the group of heat exchange tubes includes at least one heat exchange tube.

[0017] Furthermore, the heat exchanger assembly is an evaporator assembly.

[0018] The air conditioning system proposed by the present invention includes the heat exchanger assembly described in the above technical solution.

[0019] The control method of the heat exchanger assembly proposed by the present invention comprises:

[0020] Obtaining the temperature of the corresponding heat exchange tube outlet detected by each temperature sensing device of the evaporator assembly;

[0021] Calculate the temperature average value according to the temperature detected by each temperature sensing device;

[0022] If the difference between the temperature at the outlet of the heat exchange tube and the average temperature exceeds a preset range, the control valve of the liquid distributor corresponding to the heat exchange tube is controlled so that the difference between the temperature at the outlet of the heat exchange tube and the average temperature satisfies the preset range.

[0023] Furthermore, if the difference between the temperature at the outlet of the heat exchange tube and the temperature average value is less than a preset range, it is determined whether the current process of the throttling branch corresponding to the heat exchange tube is the highest level process. If not, the process is adjusted up one level.

[0024] Furthermore, if the difference between the temperature at the outlet of the heat exchange tube and the temperature average value is greater than a preset range, it is determined whether the current process of the throttling branch corresponding to the heat exchange tube is the lowest level process. If not, the process is lowered by one level.

[0025] The present invention improves the structure of the throttling shunt of the liquid distributor so that the flow length of each throttling shunt of the liquid distributor can be adjusted, so that the temperature of each throttling shunt of the liquid distributor can be adjusted individually, and the problem of uneven liquid distribution in the evaporator flow path is solved by automatically adjusting the flow of the throttling shunt of the liquid distributor. The heat exchanger assembly of the present invention has strong adjustment adaptability and is not affected by changes in the structure and operating parameters of the evaporator. Since the temperature can be kept uniform, the heat exchanger of the present invention can also achieve a uniform defrosting effect when frosting, solving the problem of severe local frosting. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0027] Figure 1 It is a structural schematic diagram of a throttling shunt according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic structural diagram of a heat exchanger assembly according to an embodiment of the present invention.

[0029] Figure 3 It is a main control flow chart of an embodiment of the present invention. Description of the drawings:

[0031] 1. Throttling branch; 11. Spiral tubular throttling branch; 12. Straight pipe branch; 13. First solenoid valve; 14. Second solenoid valve; 2. Liquid distributor; 3. Liquid pipe; 4. Heat exchanger; 5. Temperature sensing device; 6. Connecting pipe; 7. Collecting pipe. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0034] The liquid distributor provided by the present invention comprises a liquid distributor head 2 and a plurality of throttling branches 1 connected to one end of the liquid distributor head 2 , and a liquid pipe 3 connected to the other end of the liquid distributor head 2 .

[0035] Each throttling branch 1 includes multiple throttling branches, and the throttling branches of each throttling branch 1 are connected in parallel with each other, and the lengths of the multiple throttling branches of each throttling branch 1 are different, that is, the flow lengths of the throttling branches of each throttling branch 1 are different, and a control valve is also provided at the inlet of each throttling branch. The present invention uses a liquid distributor with adjustable flow length to make the refrigerant temperature in the pipeline connected to each throttling branch 1 of the liquid distributor adjustable, thereby realizing the adjustment of the temperature of the pipeline connected to each throttling branch 1.

[0036] In one embodiment, the throttling branch 1 includes at least one throttling branch 11 wound into a spiral tube shape having at least one flow loop. By winding the throttling branch with a longer flow path into a spiral tube shape, the distances between the inlet and outlet ends of multiple throttling branches with different flow paths on the corresponding projection surface are similar, thereby realizing the parallel connection of liquid separation branches with different flow path lengths within a limited length space. For example, in the projection surface where the spiral tube-shaped throttling branch 11 is parallel to the end of the spiral tube, the distances between the inlet and outlet ends of the throttling branches with different numbers of flow loops are similar.

[0037] In one embodiment, the throttling branch 1 can be a capillary tube, and the control valve can be a solenoid valve. The capillary tube and the solenoid valve can realize a throttling branch 1 with a simple structure and a small volume. In other embodiments, it can also be realized by using a common pipeline plus an electronic expansion valve.

[0038] like Figure 1As shown, in one embodiment, the liquid distributor head 2 of the liquid distributor is connected to a plurality of throttling branches 1, each throttling branch 1 includes two throttling branches, one of which is a spiral throttling branch 11, and the other throttling branch is a straight branch 12, the straight branch 12 is arranged along the axial direction of the spiral throttling branch 11, and the two ends of the straight branch 12 are respectively connected to the upper end and the lower end of the spiral throttling branch 11. Three different processes can be realized by two throttling branches with different processes, thereby meeting the needs of most evaporator components.

[0039] The flow of the throttling branch 1 includes three levels of flow, from top to bottom: the first level of flow that opens the spiral throttling branch 11 and closes the straight branch 12, the second level of flow that opens the spiral throttling branch 11 and the straight branch 12, and the third level of flow that opens the straight branch 12 and closes the spiral throttling branch 11. The first level of flow is the highest level of flow, and the third level of flow is the lowest level of flow.

[0040] The three-level process corresponds to three different control states of the solenoid valve and the flow state of the refrigerant in the capillary tube.

[0041] In the first state, corresponding to the first stage process, when the first solenoid valve 13 is opened and the second solenoid valve 14 is closed, the refrigerant flows through the spiral tube-shaped throttling branch 11. Figure 1 From the specific structure, the refrigerant passes through two more flow loops in the capillary tube, and the flow rate is the largest at this time.

[0042] The second state corresponds to the second stage process. When the first solenoid valve 13 and the second solenoid valve 14 are fully opened, the refrigerant is divided into two parts, one part flows through the spiral tube throttling branch 11, and the other part flows through the straight tube branch 12. Figure 1 From the specific structure, half of the refrigerant passes through two more flow rings in the capillary tube, while the other half does not, and the flow is in the middle.

[0043] In the third state, corresponding to the third level process, when the first solenoid valve 13 is closed and the second solenoid valve 14 is opened, the refrigerant flows through the straight pipe branch 12. Figure 1 From the specific structure, the refrigerant does not pass through the flow ring in the capillary tube and the flow is minimal.

[0044] From the control logic point of view, when the liquid distributor is used in the heat exchanger 4 assembly, all control valves of a throttling branch 1 are not allowed to be closed at the same time, and the following control logic also exists.

[0045] When the solenoid valve of a throttling branch 1 of the liquid distributor is adjusted from a first state to a second state, that is, from the current state where the first solenoid valve 13 is open and the second solenoid valve 14 is closed, to when the first solenoid valve 13 and the second solenoid valve 14 are fully open, it is called a downward adjustment by one level.

[0046] Similarly, when the solenoid valve of a throttling branch 1 is adjusted from the second state to the third state, that is, from the current state where the first solenoid valve 13 and the second solenoid valve 14 are fully open to the state where the first solenoid valve 13 is closed and the second solenoid valve 14 is open, it is also called a one-level down adjustment.

[0047] When the solenoid valve of a throttling branch 1 of the dispenser is adjusted from the third state to the second state, that is, from the current state where the first solenoid valve 13 is closed and the second solenoid valve 14 is opened, to the state where the first solenoid valve 13 and the second solenoid valve 14 are fully opened, it is called an upward adjustment by one level.

[0048] Similarly, when the solenoid valve of a throttling branch 1 is adjusted from the second state to the first state, that is, from the current state where the first solenoid valve 13 and the second solenoid valve 14 are fully opened, it is adjusted to the state where the first solenoid valve 13 is opened and the second solenoid valve 14 is closed. This is also called an upward adjustment.

[0049] Each action of the solenoid valve of each throttling branch 1 can only complete one level up or one level down.

[0050] The present invention can achieve different flow lengths for different throttling branches 1 by switching the above three states, or switching the three-level flow paths, so that the refrigerant temperature in the pipelines connecting different throttling branches 1 can be adjusted.

[0051] The present invention also protects a heat exchanger 4 component, and the heat exchanger 4 component of the present invention adopts the liquid separator in the above technical solution.

[0052] like Figure 2 As shown, the heat exchanger 4 assembly of the present invention specifically includes the following components: a heat exchanger 4, a connecting pipe 6, a collecting pipe 7, and a liquid distributor.

[0053] The heat exchanger 4 includes a plurality of heat exchange tubes, which are responsible for the heat exchange function of the heat exchanger 4 components.

[0054] The number of connecting pipes 6 is the same as the number of heat exchange pipes. Each connecting pipe 6 is connected to the outlet end of each heat exchanger 4 one by one, and then all the connecting pipes 6 are connected to a collecting pipe 7 so that the refrigerants in each connecting pipe 6 can be collected together in the collecting pipe 7.

[0055] The liquid distributor is connected to the inlet end of the heat exchanger 4, and each throttling branch 1 of the liquid distributor is connected to each heat exchange tube of the heat exchanger 4 in a one-to-one correspondence, specifically connected to the inlet end of each heat exchange tube. The throttling branch 1 of the liquid distributor can be used to adjust the temperature in different heat exchange tubes.

[0056] In one embodiment, the heat exchanger 4 assembly further includes a temperature sensing device 5. By detecting the outlet temperature of each heat exchange tube through the temperature sensing device 5, and in conjunction with the adjustable flow length of the liquid distributor, the temperature of each heat exchange tube in the heat exchanger 4 can be precisely controlled, thereby achieving uniform temperature of each heat exchange tube in the heat exchanger 4.

[0057] When the heat exchanger 4 component is an evaporator component, the connecting pipe 6 is specifically an air pipe, and the collecting pipe 7 is specifically an air collecting pipe.

[0058] Each temperature sensing device 5 detects the refrigerant temperature at the outlet end of a group of heat exchange tubes. The group of heat exchange tubes referred to in the present invention can be one heat exchange tube or multiple heat exchange tubes. In one embodiment, each group of heat exchange tubes specifically includes 2-3 heat exchange tubes.

[0059] Taking the evaporator assembly as an example, the temperature sensing device 5 is arranged on the air pipe at the outlet of the evaporator to detect the outlet temperature of each group of heat exchange tubes. For the convenience and accuracy of detection, when the number of heat exchange tubes of the evaporator is greater than or equal to 20, that is, the number of flow paths n≥20, the number of temperature sensing devices 5 m≥(1 / 3)n must be satisfied. When the number of heat exchange tubes of the evaporator is less than 20, that is, the number of flow paths n<20, the number of temperature sensing devices m≥(1 / 2)n must be satisfied. It should be noted that the temperature sensing devices 5 are arranged on the air pipe as evenly as possible and divided into several groups, each group containing 2 to 3 flow paths and a temperature sensing device 5. By default, the temperatures of the flow paths in each group are similar, and the solenoid valves act in unison, that is, in the default state, the temperatures of each throttling branch 1 are similar, and the solenoid valves of each regulating branch act in unison. Only when the temperatures in the throttling branch 1 are not similar, the solenoid valves in the corresponding throttling branch 1 are adjusted to the upper or lower level.

[0060] The control method of the heat exchanger assembly of the present invention is specifically introduced below, and the control method of the evaporator assembly is specifically used as an example for explanation.

[0061] like Figure 3 As shown, the temperature sensing device detects the temperature of the air pipe corresponding to the evaporator assembly in real time, which is recorded as T1, T2, ..., Tn. By obtaining the temperature of the air pipe detected by each temperature sensing device of the evaporator assembly, the temperature of the corresponding heat exchange tube outlet can be obtained.

[0062] The temperature average is calculated based on the temperatures detected by each temperature sensing device, and the temperature average Tm=(T1+T2+...Tn) / n.

[0063] Then, the average value is subtracted from the temperature at the outlet of each heat exchange tube, △T=Ti-Tm, i=1, 2,...n.

[0064] If the difference between the outlet temperature of a heat exchange tube (or a group of heat exchange tubes) and the average temperature meets the preset range, the control valve of the heat exchange tube (or the group of heat exchange tubes) maintains the current state, that is, maintains one of the first to third states. When the difference between the outlet temperature of the heat exchange tube and the average temperature meets the preset range, it means that the deviation temperature is within the target deviation temperature range and meets the requirements of the evaporator flow path temperature uniformity. At this time, the solenoid valve maintains the current state.

[0065] In a specific embodiment, the preset range is -T1≤△T≤T1, where T1 is the target deviation temperature. If the difference between the outlet temperature of a heat exchange tube (or a group of heat exchange tubes) and the average temperature satisfies the preset range set based on the target deviation temperature, the current state is maintained.

[0066] If the difference between the outlet temperature of a heat exchange tube (or a group of heat exchange tubes) and the average temperature exceeds a preset range, the control valve of the liquid distributor corresponding to the heat exchange tube is controlled so that the difference between the outlet temperature of the heat exchange tube and the average temperature meets the preset range.

[0067] In a specific embodiment, there are two situations in which the difference between the outlet temperature of a certain heat exchange tube (or a group of heat exchange tubes) and the average temperature exceeds a preset range.

[0068] The first is that if the difference between the outlet temperature of a certain heat pipe (or a family of heat exchange tubes) and the average temperature is less than the preset range, that is, △T<-T1, determine whether the current process of the throttling branch corresponding to the heat exchange tube is the highest level process. If not, adjust the process up one level. For example, the current state of the throttling branch corresponding to the heat exchange tube is not the first state. Assuming that it is currently in the third state, adjust it to the second state. Assuming that it is currently in the second state, adjust it to the first state. When the difference between the outlet temperature of the heat exchange tube and the average temperature is less than the preset range, it means that the deviation temperature is less than the target deviation temperature range, that is, the temperature of the corresponding flow path out of the evaporator is low and the temperature needs to be increased. This is achieved in the present invention by lengthening the capillary flow path, that is, "adjusting up one level."

[0069] The second is that if the difference between the temperature at the outlet of the heat exchange tube and the average temperature is greater than the preset range, that is, △T>T1, it is determined whether the current process of the throttling branch corresponding to the heat exchange tube is the lowest level process. If not, the process is adjusted down by one level. For example, the current state of the two throttling branches corresponding to the heat exchange tube is not the third state. Assuming that it is currently in the first state, adjust it to the second state. Assuming that it is currently in the second state, adjust it to the third state. When the difference between the temperature at the outlet of the heat exchange tube and the average temperature is greater than the preset range, it means that the deviation temperature is greater than the target deviation temperature range, that is, the temperature of the flow path out of the evaporator is relatively high and the temperature needs to be lowered. This is achieved by shortening the capillary flow path in the present invention, that is, "downgrading by one level."

[0070] The above process can be detected once, calculated once, and the above control logic can be applied once every 5 minutes. When "adjusting one level up" or "adjusting one level down" cannot be adjusted further and the target value has not been reached, the current state is maintained.

[0071] The above technical solution of the present invention is applicable to the field of refrigeration and air conditioning, and in particular to a refrigeration system with a finned evaporator liquid separation capillary. Therefore, the present invention also protects an air-conditioning system, which includes a heat exchanger assembly of the above technical solution. In the prior art, the uneven liquid separation temperature of the evaporator flow path not only affects the performance of the whole machine, but may even cause the evaporator to freeze and crack. When the air duct structure is determined, the most effective method is to add an evaporator liquid separation capillary and adjust the length of the capillary through the technical solution of the present invention. However, the frequent manual replacement of capillaries in the prior art will cause a lot of time and manpower waste. When multiple evaporators are connected in series, any changes in the previous system will cause all systems to need to be readjusted, which is extremely troublesome. The present invention solves this problem well at a relatively low cost.

[0072] The present invention utilizes temperature sensing devices, capillaries, solenoid valves and other components to identify evaporator flow paths with uneven liquid separation and uneven temperature, and automatically adjust the length of the liquid separation capillaries of these flow paths to achieve uniform liquid separation. The method is simple to control and highly practical, and can effectively solve the problem of uneven liquid separation in a commercial refrigeration multi-stage evaporator series system.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquid dispenser, comprising: A liquid dispensing head and a plurality of throttling branches connected to the liquid dispensing head, wherein each throttling branch comprises a plurality of throttling branches which are connected in parallel with each other and have different flow lengths, and a control valve arranged at the inlet of each throttling branch.

2. The liquid dispenser according to claim 1, characterized in that The throttling branch includes at least one throttling branch wound into a spiral tube shape having at least one flow loop.

3. The liquid dispenser according to claim 2, characterized in that: The throttling branch comprises two throttling branches, one of which is the spiral tube-shaped throttling branch, and the other throttling branch is a straight tube branch.

4. The liquid dispenser according to claim 3, characterized in that The process of the throttling branch includes three levels of processes, from top to bottom: the first level process of opening the spiral tubular throttling branch and closing the straight pipe branch, the second level process of opening the spiral tubular throttling branch and the straight pipe branch, and the third level process of opening the straight pipe branch and closing the spiral tubular throttling branch.

5. The liquid dispenser according to any one of claims 1 to 4, characterized in that: The throttling branch is a capillary tube.

6. The liquid dispenser according to any one of claims 1 to 4, characterized in that: The control valve is a solenoid valve.

7. A heat exchanger assembly, comprising a heat exchanger, a connecting pipe connected one by one to the outlet ends of the heat exchange tubes of the heat exchanger, and a collecting pipe for collecting the refrigerants in the connecting pipes, characterized in that: It also includes a liquid distributor as described in any one of claims 1 to 6, wherein the throttling branch of the liquid distributor is connected one by one to the inlet end of each heat exchange tube of the heat exchanger.

8. The heat exchanger assembly according to claim 7, characterized in that It also includes a temperature sensing device; each of the temperature sensing devices detects the refrigerant temperature at the outlet end of a group of heat exchange tubes.

9. The heat exchanger assembly according to claim 8, characterized in that The group of heat exchange tubes includes at least one heat exchange tube.

10. The heat exchanger assembly according to any one of claims 7 to 9, characterized in that: The heat exchanger assembly is an evaporator assembly.

11. An air conditioning system, characterized in that: Comprising the heat exchanger assembly according to any one of claims 7 to 10.

12. A method for controlling a heat exchanger assembly according to claim 10, characterized in that: include: Obtaining the temperature of the corresponding heat exchange tube outlet detected by each temperature sensing device of the evaporator assembly; Calculate the temperature average value according to the temperature detected by each temperature sensing device; If the difference between the temperature at the outlet of the heat exchange tube and the average temperature exceeds a preset range, the control valve of the liquid distributor corresponding to the heat exchange tube is controlled so that the difference between the temperature at the outlet of the heat exchange tube and the average temperature satisfies the preset range.

13. The control method of the heat exchanger assembly according to claim 12, characterized in that: If the difference between the temperature at the outlet of the heat exchange tube and the average temperature is smaller than a preset range, it is determined whether the current process of the throttling branch corresponding to the heat exchange tube is the highest level process; if not, the process is adjusted up one level.

14. The control method of the heat exchanger assembly according to claim 12, characterized in that: If the difference between the temperature at the outlet of the heat exchange tube and the average temperature is greater than a preset range, it is determined whether the current process of the throttling branch corresponding to the heat exchange tube is the lowest level process; if not, the process is adjusted down by one level.

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