Multi-flow evaporator outlet superheat balancing device, evaporator and control method

Abstract

The present invention relates to the technical field of refrigeration and air conditioning, specifically to a multi-flow path evaporator outlet superheat equalization device, evaporator and control method, the superheat equalization device comprises a shell, a connecting rod, a spring, and a displacement baffle, the shell has a refrigerant inlet and a refrigerant outlet, a temperature-sensitive deformation cavity is arranged inside the shell along the refrigerant flow direction, the two ends of the connecting rod are respectively connected to the temperature-sensitive deformation cavity and the spring, the middle part is connected to the displacement baffle, the other end of the spring is directly or indirectly connected to the shell, the temperature-sensitive deformation cavity, the connecting rod, and the spring constitute a refrigerant outlet cross-section adjustment mechanism, and the size of the refrigerant outlet cross-section is controlled by adjusting the position of the displacement baffle; each flow path of the evaporator can be connected to a superheat equalization device. The device has a simple structure, and works completely on a mechanical structure and thermal principle, does not require additional sensors and external working power supplies, and meets the requirements of low cost and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and air conditioning, and in particular to a multi-flow path evaporator outlet superheat balancing device, an evaporator and a control method. Background Art

[0002] The refrigeration principle of commonly used refrigeration and air-conditioning devices (such as refrigerators, air conditioners, and car air conditioners) is to transfer the cold generated by the evaporation of the refrigerant to the external medium (such as air, water) for heat exchange through the evaporator. In order to improve the refrigeration effect, the two-phase refrigerant must not be allowed to leave the evaporator before evaporation is complete, and the superheated area of ​​the refrigerant that has completed the phase change and has basically no refrigeration capacity must not be allowed to occupy a large evaporator area. For this reason, the superheat of the refrigerant needs to be controlled within an appropriate range. Among the existing evaporator superheat control methods, the electronic expansion valve control has a better effect. The valve body is installed at the evaporator inlet and a sensor is installed at the evaporator outlet. When the superheat measured by the sensor is too large, the valve opening is increased, thereby increasing the flow rate and achieving the effect of reducing the superheat; when the measured superheat is too small or there is no superheat, the valve opening is reduced, thereby reducing the flow rate and achieving the effect of increasing the superheat.

[0003] Multi-channel evaporators have become the mainstream form of evaporators. The advantage is that they can avoid the problem of excessive flow pressure loss in single-channel evaporators, but the disadvantage is that they increase the difficulty of superheat control. For multi-channel evaporators, the outlet state of each channel is different; while using electronic expansion valve control, one electronic valve can only control one superheat value, which is generally used to measure the superheat of the refrigerant after mixing at the outlets of each channel of the evaporator. At this time, even if the superheat after mixing is appropriate, the outlet state of each channel may not be appropriate; some channel outlets may be in a two-phase state, while others may have a large superheat. If an electronic expansion valve is arranged separately in each channel, it cannot be applied to actual products due to the high cost.

[0004] The existing method for avoiding the problem of excessively high superheat at the outlet of each flow path in a multi-flow path evaporator is to conduct some experiments in advance, and add extra capillaries to increase the resistance of the circuits where the outlet refrigerant does not have superheat in the experimental working conditions (see the document "Wu Zhigang, Ding Guoliang, Simulation of Fin-Tube Heat Exchanger with Capillary Tube to Adjust Refrigerant Flow [J]. Journal of Mechanical Engineering 2007, 43(4): 13-118"). The advantage of this method is that the cost increase is small, and the disadvantage is that the flow resistance characteristics are fixed and cannot be adjusted according to changes in working conditions, so the adjustment ability is very weak.

[0005] Therefore, there is still a lack of economical and reliable solutions for regulating the refrigerant outlet state of each flow path of a multi-flow evaporator. Summary of the invention

[0006] The object of the present invention is to provide a multi-flow evaporator outlet superheat equalization device, an evaporator and a control method, which completely rely on mechanical structure and thermal principles to work, do not require additional sensors and external working power supplies, and thus meet the requirements of low cost and high reliability.

[0007] The multi-flow path evaporator outlet superheat equalization device provided by the present invention comprises an outer shell, a connecting rod, a spring, and a displacement baffle. The outer shell has a refrigerant inlet and a refrigerant outlet. A temperature-sensitive deformation cavity is arranged inside the outer shell along the refrigerant flow direction. The two ends of the connecting rod are respectively connected to the temperature-sensitive deformation cavity and the spring, and the middle part is connected to the displacement baffle. The other end of the spring is directly or indirectly connected to the shell. The temperature-sensitive deformation cavity, the connecting rod, and the spring constitute a refrigerant outlet cross-section adjustment mechanism, and the size of the refrigerant outlet cross-section is controlled by adjusting the position of the displacement baffle.

[0008] Preferably, the temperature-sensitive deformation cavity comprises a temperature-sensitive metal plate fixed to the shell, and a deformable film connected to the shell and the temperature-sensitive metal plate respectively.

[0009] Preferably, one end of the spring is connected to the deformable film, and the other end is connected to the housing.

[0010] Preferably, it also includes a hollow adjustment screw threadedly connected to the shell, and the spring is arranged in the hollow adjustment screw, with one end connected to the hollow adjustment screw and the other end connected to the deformable film.

[0011] Preferably, it also includes a leak-proof cover, which is arranged on the part of the hollow adjusting screw extending out of the shell.

[0012] Preferably, it further comprises a limit plate, which is arranged between the displacement baffle and the spring and fixedly connected to the shell.

[0013] Preferably, the deformable film is made of a deformation recoverable material.

[0014] The present invention further provides an evaporator, wherein a multi-flow path evaporator outlet superheat equalization device is installed for the flow path whose outlet superheat of the evaporator does not meet the preset value.

[0015] The present invention also provides a method for controlling the superheat balance at an evaporator outlet, the method comprising:

[0016] S1: Determine whether the superheat of all flow outlets of the evaporator is within the specified range. If yes, go to S4; if not, go to S2.

[0017] S2. Install a multi-flow evaporator outlet superheat equalization device for the flow path whose superheat is not within the specified range and whose superheat is the smallest, and go to S3;

[0018] S3, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S4, if not, go to S2;

[0019] S4. End.

[0020] Preferably, the evaporator outlet superheat balance control method is:

[0021] S1, determine whether the superheat of all flow outlets of the evaporator is within the specified range, if yes, go to S6, if not, go to S2;

[0022] S2. Install a multi-channel evaporator outlet superheat equalization device for the channel whose superheat is not within the specified range and whose superheat is the smallest, and run it for a certain period of time, then go to S3;

[0023] S3, determine whether the superheat at the outlet of the multi-flow path evaporator outlet superheat equalization device is within the specified range, if yes, go to S6, if not, go to S4;

[0024] S4, adjust the position of the hollow adjusting screw of the superheat equalization device at the outlet of the multi-flow path evaporator until the superheat at the outlet of the flow path is within the specified range, and then go to S5;

[0025] S5, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S6, if not, go to S2;

[0026] S6. End.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) A temperature-sensitive metal plate and a deformable film are designed to respond to the superheat at the outlet of each flow path of the evaporator. The size of the refrigerant outlet cross-sectional area of ​​the device is controlled by the size of the superheat at the outlet of each flow path of the evaporator, thereby achieving the requirement of automatically balancing the superheat at the outlet of each flow path of the evaporator.

[0029] (2) A hollow adjusting screw is designed to adjust the preload force of the spring, thereby adjusting the evaporator outlet superheat to different preset values.

[0030] (3) The device has a simple structure and works entirely on mechanical structure and thermal principles. It does not require additional sensors or external power supplies, thus meeting the requirements of low cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the structure of the multi-flow path evaporator outlet superheat equalization device of Example 1;

[0032] Figure 2 This is a schematic diagram of adjusting the screw spring in the multi-flow evaporator outlet superheat equalization device to a tighter position;

[0033] Figure 3 This is a schematic diagram of adjusting the screw spring in the multi-flow evaporator outlet superheat equalization device to a looser position;

[0034] Figure 4 It is a schematic diagram of the operation of the multi-flow evaporator outlet superheat equalization device adjusting when the outlet superheat is too low;

[0035] Figure 5 It is a schematic diagram of the operation of the multi-flow evaporator outlet superheat equalization device adjusting when the outlet superheat is too high;

[0036] Figure 6 It is a structural schematic diagram of a multi-flow path evaporator outlet superheat equalization device of Example 2;

[0037] Figure 7 Schematic diagram of the connection between the evaporator of Example 3 and the multi-flow path evaporator outlet superheat equalization device;

[0038] Figure 8 Schematic diagram of the connection between the evaporator of Example 4 and the multi-flow path evaporator outlet superheat equalization device;

[0039] Fig. 9 This is a flow chart of the method for controlling the superheat balance at the evaporator outlet in Example 5;

[0040] Fig.10 This is a flow chart of the evaporator outlet superheat balance control method of Example 6.

[0041] Markings in the figure: shell 1, connecting rod 2, spring 3, displacement baffle 4, temperature-sensitive metal plate 5, deformable film 6, hollow adjustment screw 7, leak-proof cover 8, limit plate 9, refrigerant inlet 11, refrigerant outlet 12, evaporator 10, distributor 20, first flow path 30, second flow path 40, connecting pipe 50, and liquid collecting pipe 60. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] See also Figure 1The multi-flow evaporator outlet superheat balancing device of this embodiment includes a shell 1, a connecting rod 2, a spring 3, a displacement baffle 4, a temperature-sensitive metal plate 5, and a deformable film 6. The shell 1, the connecting rod 2, the displacement baffle 4, and the temperature-sensitive metal plate 5 are all made of metal materials, such as copper, aluminum, stainless steel, etc., while the deformable film 6 is made of a non-metallic material with deformable and recoverable properties, such as polypropylene, etc. The shell 1 has a refrigerant inlet 11 and a refrigerant outlet 12. A temperature-sensitive metal plate 5 is welded inside the shell 1 near the refrigerant inlet 11. The deformable film 6 is arranged in a cavity formed by the temperature-sensitive metal plate 5 and the shell 1. One end of the deformable film 6 is glued to the shell 1 by glue, and the other end is glued to the temperature-sensitive metal plate 5 by glue. The shell 1, the temperature-sensitive metal plate 5, and the deformable film 6 form a temperature-sensitive deformation cavity. A two-phase refrigerant is injected into the temperature-sensitive deformation cavity. When the refrigerant flows into the shell 1 from the refrigerant inlet 11, the temperature-sensitive metal plate 5 can transfer the temperature of the refrigerant to the two-phase refrigerant in the temperature-sensitive deformation cavity. The pressure of the two-phase refrigerant changes with the change of temperature, causing the pressure on the deformable film 6 to change and produce deformation. One end of the connecting rod 2 passes through the temperature-sensitive metal plate 5 and is bonded to the deformable film 6, and the other end is hinged to the spring 3. A displacement baffle 4 is welded in the middle of the connecting rod 2. Figure 1 It can be seen that the displacement baffle 4 is arranged along the length direction of the refrigerant outlet 12. By adjusting the position of the displacement baffle 4, the cross-sectional area of ​​the refrigerant outlet 12 can be changed, thereby controlling the flow rate of the refrigerant. The temperature-sensitive deformation cavity, the connecting rod 2, and the spring 3 constitute a refrigerant outlet cross-sectional adjustment mechanism. When the deformation of the deformable film 6 increases, the connecting rod 2 squeezes the spring 3 and drives the displacement baffle 4 to move to the side of the spring 3, increasing the refrigerant flow rate. Conversely, when the deformation of the deformable film 6 decreases, the refrigerant flow rate is reduced.

[0045] As a preferred implementation of this embodiment, in order to adjust the preload force of the spring 3, the superheat equalization device of this embodiment also includes a hollow adjustment screw 7 threadedly connected to the shell 1, and the spring 3 is arranged in the hollow adjustment screw 7, one end of which is connected to the hollow adjustment screw 7, and the other end is connected to the deformable film 6.

[0046] like Figure 2 The figure shows a situation where the preload force of the spring 3 is large. When the hollow adjustment screw 7 is screwed to a deeper position, the spring 3 will be in a tighter state, thereby obtaining a larger preload force, and when the pressure on the deformable film 6 remains unchanged, the connecting rod 2 will move the displacement baffle 4 to the left.

[0047] like Figure 3The figure shows a situation where the preload force of the spring 3 is small. When the hollow adjustment screw 7 is screwed to a shallower position, the spring 3 will be in a looser state, thereby obtaining a smaller preload force. When the pressure on the deformable film 6 remains unchanged, the connecting rod 2 will move the displacement baffle 4 to the right.

[0048] As a preferred implementation of this embodiment, the superheat equalization device of this embodiment further includes a leakproof cover 8, which is provided to cover the portion of the hollow adjustment screw 7 extending outside the housing 1. Figure 1 As shown, the housing 1 has a protrusion, and the leak-proof cover 8 is screwed to the protrusion.

[0049] As a preferred implementation of this embodiment, in order to limit the distance that the displacement baffle 4 moves toward the spring 3 side, the superheat equalization device of this embodiment also includes a limit plate 9, which is arranged between the displacement baffle 4 and the spring 3 and fixedly connected to the shell 1.

[0050] The working principle of the superheat equalization device of this embodiment is as follows:

[0051] like Figure 4 The figure shows the operation mode of the superheat equalization device of this embodiment when the outlet superheat is too low. When the adjustment action of this embodiment has not yet occurred, a certain flow path of the evaporator does not overheat or the superheat is too low at the outlet due to excessive mass flow. After the adjustment action occurs, due to the low temperature of the refrigerant at the refrigerant inlet 11, the temperature-sensitive metal plate 5 transfers the lower temperature to the two-phase refrigerant in the temperature-sensitive deformation cavity. The pressure of the two-phase refrigerant decreases with the decrease in temperature, causing the deformable film 6 to be subjected to a reduced pressure of the two-phase refrigerant, the deformation is reduced, and the displacement baffle 4 is driven to move to the left through the connecting rod 2, thereby reducing the flow area of ​​the refrigerant outlet 12 of the device, reducing the refrigerant mass flow, and achieving the effect of increasing the superheat.

[0052] like Figure 5 The figure shows the operation mode of the superheat equalization device of this embodiment when the outlet superheat is too large. When the adjustment action of this embodiment has not yet occurred, the outlet superheat is too large due to the small mass flow rate in a certain flow path of the evaporator. After the adjustment action occurs, due to the high temperature of the refrigerant at the refrigerant inlet 11 of the device, the temperature-sensitive metal plate 5 transfers the higher temperature to the two-phase refrigerant in the temperature-sensitive deformation cavity. The pressure of the two-phase refrigerant increases with the increase of temperature, causing the deformable film 6 to be subjected to the increased pressure of the two-phase refrigerant, the deformation increases, and the displacement baffle 4 is driven to move to the right through the connecting rod 2, thereby increasing the flow area of ​​the refrigerant outlet 12 of the device, increasing the refrigerant mass flow, and achieving the effect of a smaller superheat.

[0053] Example 2

[0054] Reference Figure 6The difference between the multi-flow evaporator outlet superheat equalization device of this embodiment and the embodiment 1 is that one end of the spring 3 is connected to the connecting rod 2, and the other end is directly fixedly connected to the housing 1. The superheat equalization device of this embodiment does not have a hollow adjustment screw 7 and a leakproof cover 8. This structure cannot adjust the preload force of the spring 3 during the operation of the device, so its ability to adjust the superheat of the evaporator outlet is not as good as the superheat equalization device of embodiment 1.

[0055] Example 3

[0056] Reference Figure 7 , this embodiment provides an evaporator, Figure 7 1 shows two flow paths of the evaporator 10, namely, the first flow path 30 and the second flow path 40 connected by the distributor 20. The first flow path 30 and the second flow path 40 of this embodiment are respectively connected to the refrigerant inlet 11 of a multi-flow evaporator outlet superheat equalization device, and the refrigerant outlet 12 is connected to the collecting pipe 60 through the connecting pipe 50. The superheat of the first flow path 30 and the second flow path 40 can be adjusted by the superheat equalization device described in Example 1.

[0057] Example 4

[0058] Reference Figure 8 The evaporator of this embodiment is different from that of Embodiment 3 in that only the first flow path 30 is connected to the superheat equalization device, and the second flow path 40 is directly connected to the liquid collecting pipe 60. The superheat at the outlet of the first flow path 30 is not within the appropriate range, so a superheat equalization device is installed, while the superheat at the outlet of the second flow path 40 is already within the appropriate range, so a superheat equalization device is not required.

[0059] Example 5

[0060] Reference Fig. 9 This embodiment provides a method for controlling the superheat balance at an evaporator outlet, the method comprising:

[0061] S1: Determine whether the superheat of all flow outlets of the evaporator is within the specified range. If yes, go to S4; if not, go to S2.

[0062] S2. Install a multi-flow evaporator outlet superheat equalization device for the flow path whose superheat is not within the specified range and whose superheat is the smallest, and go to S3;

[0063] S3, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S4, if not, go to S2;

[0064] S4, end. Step 2 of this embodiment adopts the superheat equalization device described in Embodiment 2, which has no hollow adjustment screw, and the depth of the screw inserted into the shell cannot be manually adjusted, so it is difficult to adjust the cross-sectional area of ​​the refrigerant outlet. The displacement baffle can only be adjusted by the self-adjustment of the temperature-sensitive deformation cavity to achieve the adjustment of the refrigerant outlet cross section.

[0065] Example 6

[0066] Reference Fig.10 , the present embodiment provides a method for controlling the evaporator outlet superheat balance as follows:

[0067] S1, determine whether the superheat of all flow outlets of the evaporator is within the specified range, if yes, go to S6, if not, go to S2;

[0068] S2. Install a multi-channel evaporator outlet superheat equalization device for the channel whose superheat is not within the specified range and whose superheat is the smallest, and run it for a certain period of time, then go to S3;

[0069] S3, determine whether the superheat at the outlet of the multi-flow path evaporator outlet superheat equalization device is within the specified range, if yes, go to S6, if not, go to S4;

[0070] S4, adjust the position of the hollow adjusting screw of the superheat equalization device at the outlet of the multi-flow path evaporator until the superheat at the outlet of the flow path is within the specified range, and then go to S5;

[0071] S5, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S6, if not, go to S2;

[0072] S6. End.

[0073] Step 2 of this embodiment adopts the superheat equalization device described in Example 1, which is provided with a hollow adjusting screw. The depth of the screw inserted into the shell can be manually adjusted to adjust the cross-sectional area of ​​the refrigerant outlet. It does not rely solely on the self-adjustment of the temperature-sensitive deformation cavity to adjust the displacement baffle. Therefore, the control method of this embodiment is more comprehensive and can better ensure that the superheat of each flow path outlet of the evaporator is within the control range.

[0074] 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 multi-flow evaporator outlet superheat balancing device, characterized in that: It includes an outer shell, a connecting rod, a spring, and a displacement baffle. The outer shell has a refrigerant inlet and a refrigerant outlet. A temperature-sensitive deformation cavity is arranged inside the outer shell along the refrigerant flow direction. The temperature-sensitive deformation cavity includes a temperature-sensitive metal plate fixed to the shell, and a deformable film respectively connected to the shell and the temperature-sensitive metal plate. The two ends of the connecting rod are respectively connected to the temperature-sensitive deformation cavity and the spring, and the middle part is connected to the displacement baffle. The other end of the spring is directly or indirectly connected to the shell. The temperature-sensitive deformation cavity, the connecting rod, and the spring constitute a refrigerant outlet cross-section adjustment mechanism. The size of the refrigerant outlet cross-section is controlled by adjusting the position of the displacement baffle.

2. The multi-flow evaporator outlet superheat balancing device according to claim 1, characterized in that: One end of the spring is connected to the deformable film, and the other end is connected to the shell.

3. The multi-flow path evaporator outlet superheat balancing device according to claim 1, characterized in that: It also includes a hollow adjusting screw threadedly connected to the shell. The spring is arranged in the hollow adjusting screw, one end of the spring is connected to the hollow adjusting screw, and the other end is connected to the deformable film.

4. The multi-flow path evaporator outlet superheat balancing device according to claim 3, characterized in that: The invention also comprises a leak-proof cover, which is arranged on the part of the hollow adjusting screw extending out of the housing.

5. The multi-flow path evaporator outlet superheat balancing device according to claim 1, characterized in that: It also includes a limit plate, which is arranged between the displacement baffle and the spring and is fixedly connected to the shell.

6. The multi-flow path evaporator outlet superheat balancing device according to claim 1, characterized in that: The deformable film is made of a deformation recoverable material.

7. An evaporator, characterized in that: The flow path where the evaporator outlet superheat does not meet the preset value is installed with the multi-flow path evaporator outlet superheat equalization device as described in any one of claims 1-6.

8. A method for controlling the superheat balance at an evaporator outlet, characterized in that: The method is: S1: Determine whether the superheat of all flow outlets of the evaporator is within the specified range. If yes, go to S4; if not, go to S2. S2. Install the multi-flow path evaporator outlet superheat equalization device as claimed in claim 1, 2, 5 or 6 for the flow path whose superheat is not within the specified range and whose superheat is the smallest, and go to S3; S3, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S4, if not, go to S2; S4. End.

9. The evaporator outlet superheat balance control method according to claim 8, characterized in that: The method is: S1, determine whether the superheat of all flow outlets of the evaporator is within the specified range, if yes, go to S6, if not, go to S2; S2, install the multi-flow path evaporator outlet superheat equalization device as claimed in claim 3 or 4 for the flow path whose superheat is not within the specified range and whose superheat is the smallest, and run it for a certain period of time, and then go to S3; S3, determine whether the superheat at the outlet of the multi-flow path evaporator outlet superheat equalization device is within the specified range, if yes, go to S6, if not, go to S4; S4, adjust the position of the hollow adjusting screw of the superheat equalization device at the outlet of the multi-flow path evaporator until the superheat at the outlet of the flow path is within the specified range, and then go to S5; S5, determine whether the superheat at the outlet of the remaining flow paths of the evaporator is within the specified range, if yes, go to S6, if not, go to S2; S6. End.

Images