Stirling cryogenic vacuum pump and its control system

Abstract

The present invention relates to the field of vacuum pumps and is used to solve the problems that low-temperature water vapor pumps are bulky, difficult to move, and lack the ability to automatically adjust between regeneration procedures and low-temperature operations. Specifically, the present invention relates to a Stirling low-temperature vacuum pump and its control system. The control system includes a regeneration control module, a coordination control module, a low-temperature monitoring module, and an operation calibration module. The present invention uses an actively reversible motor to switch between the regeneration process and the low-temperature process, so that a single motor can realize multi-process system operation, reducing the volume of the low-temperature water vapor pump. At the same time, by miniaturizing the equipment components, the portability of the low-temperature water vapor pump is greatly improved. By integrating temperature sensors and control systems at different positions in the low-temperature water vapor pump, the low-temperature water vapor pump can realize automatic judgment and analysis of the low-temperature effect and autonomous decision-making on the switching of the regeneration process.

Description

Technical Field

[0001] The present invention relates to the field of vacuum pumps, in particular to a Stirling cryogenic vacuum pump and a control system thereof. Background Art

[0002] A cryopump is a high vacuum pump that uses a refrigerator to expand and refrigerate a cryogenic surface, and then uses that surface to condense or adsorb gases. Cryopumps have advantages such as high pumping speed, particularly good at pumping water vapor, and high ultimate vacuum.

[0003] As the amount of condensed or adsorbed gas inside the cryopump increases, the cryopump's pumping capacity will weaken. At this time, the cryopump needs to be regenerated to restore its initial performance. When starting regeneration, first close the high vacuum valve between the cryopump and the vacuum chamber. By heating or natural temperature increase, the various gases condensed or adsorbed on the surface are released and discharged to the outside of the pump.

[0004] At present, the existing cryogenic water vapor pumps still have shortcomings when in use. In order to meet the needs of the two stages of refrigeration and regeneration, the existing cryogenic water vapor pumps require two energy supply components, namely, regeneration and refrigeration. As a result, the overall design of the cryogenic water vapor pump is bulky and mostly fixed, which is not convenient for movement. At the same time, the regeneration program of the existing cryogenic water vapor pump is generally switched manually and lacks automatic control capabilities.

[0005] In response to the above technical problems, this application proposes a solution. Summary of the Invention

[0006] The present invention uses an actively reversible motor to switch between the regeneration process and the low-temperature process, so that a single motor can realize multi-process system operation, reduce the volume of the low-temperature water vapor pump, and at the same time greatly improve the portability of the low-temperature water vapor pump by miniaturizing the equipment components. By integrating temperature sensors and control systems at different positions in the low-temperature water vapor pump, the low-temperature water vapor pump can automatically judge and analyze the low-temperature effect, thereby making autonomous decisions on switching the regeneration process, avoiding the decline in the operating effect of the low-temperature water vapor pump due to frosting during manual switching, and solving the problems that the low-temperature water vapor pump is bulky, not conducive to mobility, and lacks the ability to automatically adjust between the regeneration process and low-temperature operation, and proposes a Stirling low-temperature vacuum pump and its control system.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A Stirling cryogenic vacuum pump comprises an equipment housing, a DC brushless motor fixedly connected to the bottom of the equipment housing, a refrigerator radiator fixedly mounted on the other side of the equipment housing, an active cooling fan mounted on the outside of the refrigerator radiator, a KF sealing flange fixedly mounted on the top of the equipment housing, and a three-way pipe connected above the KF sealing flange;

[0009] A cold finger is fixedly installed inside the three-way pipe, a condensing fin is fixedly installed on the top of the cold finger, the brushless DC motor, the cold finger and the condensing fin constitute a Stirling refrigerator structure, the condensing fin is connected to the cold head on the top of the cold finger by vacuum brazing, and a parallel thermometer is installed on the central axis of the condensing fin;

[0010] A data terminal is installed on the device housing, and the data terminal is connected to the parallel thermometer. A wiring terminal is fixedly installed on the DC brushless motor, and the wiring terminal is connected to some of the binding posts on the data terminal through wires. Some of the binding posts on the data terminal are connected to the external temperature display module;

[0011] The tail of the brushless DC motor is integrated with a control board, which includes a low-temperature water vapor pump control system. The operation of the brushless DC motor is controlled by the low-temperature water vapor pump control system, and data is read through a parallel thermometer.

[0012] As a preferred embodiment of the present invention, the parallel thermometer includes two groups of thermometers, and each thermometer is respectively connected to two terminals of the data terminal. The two groups of terminals in the data terminal import the data of one group of thermometers into the terminal, and the other two groups of terminals in the data terminal import the data of the other group of thermometers into the external control module.

[0013] As a preferred embodiment of the present invention, the brushless DC motor controls the motor to rotate in the reverse direction through a control signal, thereby driving the refrigerant to operate in the reverse direction;

[0014] One end of the three-way pipe is externally connected to the container end, and a sealing component is provided between the container end and the three-way pipe, wherein the sealing component can completely isolate the connectivity between the three-way pipe and the container end;

[0015] A nitrogen pipeline is provided in the equipment shell, and the nitrogen pipeline is connected to the three-way pipeline.

[0016] Stirling cryogenic vacuum pump control system, including regeneration control module, coordination control module, low temperature monitoring module and operation calibration module;

[0017] The operation calibration module collects the gas vacuum degree in the container end and generates a low temperature normal signal or a low temperature abnormal signal based on the gas vacuum degree result;

[0018] The low-temperature monitoring module is used to obtain temperature data from the parallel thermometers and determine the temperatures of the parallel thermometers to obtain low-temperature operating parameters and high-temperature operating parameters;

[0019] The regeneration control module is used to generate a regeneration transition signal to control the brushless DC motor to reverse;

[0020] The coordinated control module can obtain a regeneration transition signal and a low-temperature operation signal, and control the coordinated operation of the nitrogen pipeline and the sealing component according to the regeneration transition signal or the low-temperature operation signal.

[0021] As a preferred embodiment of the present invention, the low-temperature monitoring module obtains the current operating mode of the brushless DC motor, where the operating mode includes a forward mode and a reverse mode. When in the forward mode, the temperature parameter of the parallel thermometer is compared with a set low-temperature range to determine whether the temperature parameter reaches the set low-temperature range;

[0022] When in the reversal mode, the temperature parameter of the parallel thermometer is compared with the set high temperature range to determine whether the temperature parameter reaches the set high temperature range;

[0023] The low temperature monitoring module adjusts the operating power of the brushless DC motor according to whether the temperature parameter reaches the set low temperature / high temperature range.

[0024] As a preferred embodiment of the present invention, the operation calibration module obtains the temperature parameters of the parallel thermometers through the low-temperature monitoring module, and compares the temperature parameters of the parallel thermometers with the gas vacuum degree by weight, and generates a low-temperature abnormality signal or a low-temperature normal signal according to the comparison result;

[0025] After acquiring the low-temperature abnormality signal, the operation calibration module sends the low-temperature abnormality signal to the regeneration control module.

[0026] As a preferred embodiment of the present invention, after the regeneration control module obtains the low-temperature abnormality signal, it automatically generates a regeneration transition signal, obtains the preset regeneration process duration, operates according to the regeneration process duration, and converts to a low-temperature operation signal after the regeneration process duration reaches the set value.

[0027] As a preferred embodiment of the present invention, after obtaining the regeneration transition signal, the coordination control module controls the sealing component to cut off the connection between the three-way pipe and the container end through the control signal, and controls the nitrogen pipe to purge nitrogen into the three-way pipe;

[0028] After obtaining the low-temperature operation signal, the coordinated control module controls the nitrogen pipeline to be closed and controls the sealing component to be opened.

[0029] As a preferred embodiment of the present invention, the Stirling refrigerator structure composed of the brushless DC motor, cold fingers and condensing fins can be replaced with a linear refrigerator structure.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. In the present invention, the regeneration process and the low-temperature process are switched by an actively reversible motor, so that a single motor can realize multi-process system operation, reduce the volume of the low-temperature water vapor pump, and at the same time greatly improve the portability of the low-temperature water vapor pump by miniaturizing the equipment components.

[0032] 2. In the present invention, by integrating temperature sensors and control systems at different positions in the low-temperature steam pump, it is possible to realize automatic judgment and analysis of the low-temperature effect of the low-temperature steam pump, thereby making autonomous decisions on switching the regeneration process, and avoiding the decline in the operating performance of the low-temperature steam pump due to frosting during manual switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0034] Figure 1 It is a main structural diagram of the present invention;

[0035] Figure 2 Schematic diagram of the condensing fin structure of the present invention;

[0036] Figure 3 Schematic diagram of the linear refrigerator structure of the present invention;

[0037] Figure 4 is a system block diagram of the present invention;

[0038] Figure 5 It is a system flow chart of the present invention.

[0039] In the figure: 1. Three-way pipe; 2. Active cooling fan; 3. Brushless DC motor; 4. KF sealing flange; 5. Condensing fins; 6. Parallel thermometer; 7. Wiring terminal; 8. Data terminal; 9. Cold finger; 10. Equipment housing; 11. Refrigeration radiator. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Example 1:

[0042] See also Figure 1 - Figure 5 As shown, the Stirling cryogenic vacuum pump includes an equipment housing 10, a DC brushless motor 3 is fixedly connected to the bottom of the equipment housing 10, a refrigerator radiator 11 is fixedly installed on the other side of the equipment housing 10, an active cooling fan 2 is installed outside the refrigerator radiator 11, a KF sealing flange 4 is fixedly installed on the top of the equipment housing 10, and a three-way pipe 1 is connected above the KF sealing flange 4;

[0043] One end of the three-way pipe 1 is externally connected to a container end, and a sealing component is provided between the container end and the three-way pipe 1, wherein the sealing component can completely isolate the connectivity between the three-way pipe 1 and the container end;

[0044] A cold finger 9 is fixedly installed inside the three-way pipe 1, and a condensing fin 5 is fixedly installed on the top of the cold finger 9. The DC brushless motor 3, the cold finger 9 and the condensing fin 5 constitute a Stirling refrigerator structure. The condensing fin 5 and the cold head on the top of the cold finger 9 are connected by vacuum brazing. The outer surface of the condensing fin 5 is bright nickel plated and polished. A parallel thermometer 6 is installed on the central axis of the condensing fin 5.

[0045] A nitrogen pipeline is provided in the equipment housing 10, and the nitrogen pipeline is connected to the three-way pipeline 1;

[0046] A data terminal 8 is mounted on the device housing 10 and is connected to the parallel thermometer 6. A terminal 7 is fixedly mounted on the DC brushless motor 3 and is connected to some terminals on the data terminal 8 via wires. Some terminals on the data terminal 8 are connected to an external temperature display module.

[0047] The data terminal 8 includes four groups of terminals, and the parallel thermometer 6 includes two groups of thermometers, and each thermometer is connected to two terminals of the data terminal 8 respectively. The two groups of terminals in the data terminal 8 import the data of one group of thermometers into the terminal 7, and the other two groups of terminals in the data terminal 8 import the data of the other group of thermometers into the external temperature display module;

[0048] A control board is integrated at the tail of the DC brushless motor 3. The control board includes a low-temperature water vapor pump control system. The operation of the DC brushless motor 3 is controlled by the low-temperature water vapor pump control system, and data is read through the parallel thermometer 6. The DC brushless motor 3 controls the motor to rotate in the opposite direction through the control signal, thereby driving the Stirling refrigerator to run in the opposite direction, realizing the reverse heating and regeneration process of the DC brushless motor 3, thereby reducing the driving components in the overall mechanism, effectively reducing the size of the equipment, so that the weight of the equipment can be reduced to 1KG, and the length of the equipment can be reduced to 15cm.

[0049] Example 2:

[0050] See also Figure 1 - Figure 5 As shown, the Stirling cryogenic vacuum pump control system includes a regeneration control module, a coordination control module, a cryogenic monitoring module and an operation calibration module;

[0051] The low temperature monitoring module is used to obtain the temperature data of the parallel thermometer 6 and to judge the temperature of the parallel thermometer 6;

[0052] The low-temperature monitoring module obtains the current operating mode of the brushless DC motor 3, wherein the operating mode includes a forward mode and a reverse mode. When in the forward mode, the temperature parameter of the parallel thermometer 6 is compared with the set low-temperature range to determine whether the temperature parameter reaches the set low-temperature range and record it as the low-temperature operating parameter;

[0053] When in the reverse mode, the temperature parameter of the parallel thermometer 6 is compared with the set high temperature range to determine whether the temperature parameter reaches the set high temperature range and record it as the high temperature operation parameter;

[0054] The low temperature range and high temperature range can be adjusted online through the control panel, controller or control software to adapt to different working environments and work tasks. The cooling temperature can be set to 110K~150K, and the heating temperature can be set to 393K~423K;

[0055] The low temperature monitoring module adjusts the operating power of the brushless DC motor 3 according to whether the low temperature / high temperature operating parameters reach the set low temperature / high temperature range;

[0056] The operation calibration module collects the gas vacuum degree in the container end, and obtains the temperature parameter of the parallel thermometer 6 through the low-temperature monitoring module. The temperature parameter of the parallel thermometer 6 is compared with the gas vacuum degree in the container end by weight. If qT is greater than or equal to t, a low-temperature normal signal is generated. If qT is less than t, a low-temperature abnormal signal is generated, where T is the temperature parameter of the parallel thermometer 6, t is the gas vacuum degree, and q is the set weight coefficient. The value of q is related to the heat exchange efficiency of the gas when passing through the condensing fins 5, the volume of the container end, and the water vapor content of the gas;

[0057] After obtaining the low temperature abnormality signal, the operation calibration module sends the low temperature abnormality signal to the regeneration control module;

[0058] The regeneration control module is used to generate a regeneration transition signal and, after obtaining a low-temperature abnormality signal, control the brushless DC motor 3 to reverse, and simultaneously obtain a preset regeneration process duration, operate according to the regeneration process duration, and, after the regeneration process duration reaches a set value, switch to a low-temperature operation signal;

[0059] The coordinated control module can obtain the regeneration transition signal and the low-temperature operation signal, and control the coordinated operation of the nitrogen pipeline and the sealing component according to the regeneration transition signal or the low-temperature operation signal; specifically:

[0060] After receiving the regeneration conversion signal, the coordination control module controls the sealing component to cut off the connection between the three-way pipe 1 and the container end through the control signal, and controls the nitrogen pipe to purge nitrogen into the three-way pipe 1, thereby blowing out the frost of the melted water vapor on the condensing fins 5;

[0061] In addition, the miniaturized Stirling cryogenic vacuum pump can be directly removed and the condensing fins 5 can be blown directly with a handheld blower to achieve the purpose of blowing out the melted water, further reducing the volume occupied by the nitrogen pipeline, simplifying the equipment structure, and reducing equipment costs.

[0062] After obtaining the low-temperature operation signal, the coordinated control module controls the nitrogen pipeline to be closed and controls the sealing component to be opened.

[0063] Example 3:

[0064] See also Figure 3 As shown, the Stirling refrigerator structure composed of the brushless DC motor 3, the cold finger 9 and the condensing fins 5 can be replaced with a linear refrigerator structure, thereby enriching the refrigerator types and improving the application field and use flexibility of the low-temperature vacuum pump.

[0065] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Stirling cryogenic vacuum pump, characterized in that, The device comprises a housing (10), a DC brushless motor (3) fixedly connected to the bottom of the housing (10), a refrigerator radiator (11) fixedly mounted on the other side of the housing (10), an active cooling fan (2) mounted on the outside of the refrigerator radiator (11), a KF sealing flange (4) fixedly mounted on the top of the housing (10), and a three-way pipe (1) connected above the KF sealing flange (4); A cold finger (9) is fixedly installed inside the three-way pipe (1), and a condensing fin (5) is fixedly installed on the top of the cold finger (9). The DC brushless motor (3), the cold finger (9) and the condensing fin (5) constitute a Stirling refrigerator structure. The condensing fin (5) and the cold head at the top of the cold finger (9) are connected by vacuum brazing. A parallel thermometer (6) is installed on the central axis of the condensing fin (5); A data terminal (8) is installed on the device housing (10), and the data terminal (8) is connected to the parallel thermometer (6). A wiring terminal (7) is fixedly installed on the DC brushless motor (3), and the wiring terminal (7) is connected to part of the wiring posts on the data terminal (8) through a wire, and part of the wiring posts of the data terminal (8) are connected to an external temperature display module; The brushless DC motor (3) is integrated with a control board at the rear end, and the control board includes a low-temperature water vapor pump control system, which controls the operation of the brushless DC motor (3) through the low-temperature water vapor pump control system and reads data through the parallel thermometer (6); The Stirling cryogenic vacuum pump control system includes a regeneration control module, a coordination control module, a low-temperature monitoring module, and an operation calibration module; The operation calibration module collects the gas vacuum degree in the container end and generates a low temperature normal signal or a low temperature abnormal signal based on the gas vacuum degree result; The operation calibration module obtains the temperature parameter of the parallel thermometer (6) through the low temperature monitoring module, and compares the temperature parameter of the parallel thermometer (6) with the gas vacuum degree by weight. If qT is greater than or equal to t, a low temperature normal signal is generated; if qT is less than t, a low temperature abnormal signal is generated, wherein T is the temperature parameter of the parallel thermometer (6), t is the gas vacuum degree, and q is a set weight coefficient; After acquiring the low-temperature abnormality signal, the operation calibration module sends the low-temperature abnormality signal to the regeneration control module.

2. The Stirling cryogenic vacuum pump according to claim 1, characterized in that The data terminal (8) includes four groups of terminals, the parallel thermometer (6) includes two groups of thermometers, and each thermometer is connected to two terminals of the data terminal (8), respectively. The two groups of terminals in the data terminal (8) import the data of one group of thermometers into the terminal (7), and the other two groups of terminals in the data terminal (8) import the data of the other group of thermometers into the external control module.

3. The Stirling cryogenic vacuum pump according to claim 1, wherein: The brushless DC motor (3) controls the motor to rotate in the reverse direction through a control signal, thereby driving the refrigerant to operate in the reverse direction; One end of the three-way pipe (1) is externally connected to a container end, and a sealing component is provided between the container end and the three-way pipe (1), wherein the sealing component can completely cut off the connectivity between the three-way pipe (1) and the container end; A nitrogen pipeline is provided in the equipment housing (10), and the nitrogen pipeline is connected to the three-way pipeline (1).

4. The Stirling cryogenic vacuum pump according to claim 1, characterized in that The low-temperature monitoring module is used to obtain temperature data of the parallel thermometer (6), and to judge the temperature of the parallel thermometer (6) to obtain low-temperature operating parameters and high-temperature operating parameters; The regeneration control module is used to generate a regeneration conversion signal to control the brushless DC motor (3) to reverse; The coordinated control module can obtain a regeneration transition signal and a low-temperature operation signal, and control the coordinated operation of the nitrogen pipeline and the sealing component according to the regeneration transition signal or the low-temperature operation signal.

5. The Stirling cryogenic vacuum pump according to claim 4, characterized in that The low temperature monitoring module obtains the current operating mode of the brushless DC motor (3), wherein the operating mode includes a forward mode and a reverse mode. When in the forward mode, the temperature parameter of the parallel thermometer (6) is compared with the set low temperature range to determine whether the temperature parameter reaches the set low temperature range; When in the reversal mode, the temperature parameter of the parallel thermometer (6) is compared with the set high temperature range to determine whether the temperature parameter reaches the set high temperature range; The low temperature monitoring module adjusts the operating power of the brushless DC motor (3) according to whether the temperature parameter reaches a set low temperature / high temperature range.

6. The Stirling cryogenic vacuum pump according to claim 4, characterized in that After the regeneration control module obtains the low-temperature abnormality signal, it automatically generates a regeneration transition signal, obtains the preset regeneration process duration, operates according to the regeneration process duration, and converts to a low-temperature operation signal after the regeneration process duration reaches the set value.

7. The Stirling cryogenic vacuum pump according to claim 4, characterized in that After obtaining the regeneration conversion signal, the coordination control module controls the sealing component to cut off the connection between the three-way pipe (1) and the container end through the control signal, and controls the nitrogen pipe to purge nitrogen into the three-way pipe (1); After obtaining the low-temperature operation signal, the coordinated control module controls the nitrogen pipeline to be closed and controls the sealing component to be opened.

8. The Stirling cryogenic vacuum pump according to claim 1, wherein: The brushless DC motor (3), the cold finger (9) and the condensing fin (5) form a linear refrigerator structure.

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