Low-temperature vacuum pump structure with inlet air precooling function

Abstract

The low-temperature vacuum pump structure comprises a vacuum cover, a refrigerating machine and a pre-cooling structure, the vacuum cover comprises a surrounding section and a neck pipe section, an anti-radiation screen is arranged in the surrounding section, a baffle is connected to the top of the anti-radiation screen, and a condensation plate assembly is arranged in the space defined by the anti-radiation screen and the baffle; the refrigerating machine comprises a first-stage refrigerating section and a second-stage refrigerating section, the anti-radiation screen is connected with the first-stage refrigerating section and conducts heat, and the condensation plate assembly is connected with the second-stage refrigerating section; the pre-cooling structure comprises a pre-cooling air inlet pipe and a pre-cooling exhaust pipe which are arranged on the surrounding section, and a pre-cooling pipe row arranged above the baffle. The pre-cooling gas inlet pipe and the pre-cooling gas outlet pipe penetrate through the surrounding section and are connected with the two ends of the pre-cooling pipe row correspondingly, and high-temperature gas entering the vacuum cover flows through the pre-cooling pipe row to be pre-cooled, then makes contact with the baffle and then is frozen by the condensation plate assembly. According to the low-temperature vacuum pump, the temperature of gas entering the low-temperature vacuum pump can be effectively reduced, so that normal operation of the pump under the condition of high-temperature gas is ensured.

Description

Technical Field

[0001] This invention relates to the field of cryogenic vacuum pump technology, and specifically to a cryogenic vacuum pump structure with inlet pre-cooling. Background Technology

[0002] Cryogenic vacuum pumps utilize a refrigerator to cool the gas and lower the temperature of the connected condenser plate assembly to extremely low levels. The gas inside the vacuum chamber connected to the cryogenic vacuum pump is frozen by the low-temperature condenser plate assembly to maintain the vacuum level within the chamber. However, some vacuum chambers contain high-temperature baking devices, resulting in excessively high gas temperatures. In such cases, the cooling capacity generated by the refrigerator is insufficient to lower the gas temperature, causing the temperature of the refrigerator and condenser plate assembly to rise, leading to the failure of the cryogenic vacuum pump and its inability to function properly. Summary of the Invention

[0003] Purpose of the invention: The present invention provides a structure for a cryogenic vacuum pump with pre-cooled inlet gas, which can effectively reduce the temperature of the gas entering the cryogenic vacuum pump, so as to ensure the normal operation of the pump in the presence of high-temperature gas.

[0004] Technical Solution: The present invention provides a low-temperature vacuum pump structure for inlet precooling, comprising a vacuum shroud, a refrigerator, and a precooling structure. The vacuum shroud includes an enclosing section and a neck section, the neck section being disposed on the circumferential side of the enclosing section. A radiation shield is disposed inside the enclosing section, and a baffle is connected to the top of the radiation shield. A condenser plate assembly is disposed within the space enclosed by the radiation shield and the baffle. The refrigerator includes a primary refrigeration section and a secondary refrigeration section. The primary refrigeration section is enclosed within the neck section, and the secondary refrigeration section is enclosed within the enclosing section. The radiation shield is connected to the primary refrigeration section and conducts heat, and the condenser plate assembly is connected to the secondary refrigeration section. The precooling structure includes a precooling inlet pipe, a precooling exhaust pipe, and a precooling pipe array disposed on the enclosure section. The precooling inlet pipe and the precooling exhaust pipe pass through the enclosure section and are respectively connected to both ends of the precooling pipe array. An external precooling gas source is connected to the precooling inlet pipe, so that the precooling gas flows through the precooling pipe array and is discharged from the precooling exhaust pipe. The high-temperature gas entering the vacuum chamber flows through the precooling pipe array, is precooled and cooled, and then contacts the baffle and is frozen by the condenser plate assembly.

[0005] Furthermore, a purge pipe is also provided on the surrounding section, and the precooling air intake pipe and the purge pipe are connected to a three-way solenoid valve. The three-way solenoid valve is used to selectively connect the precooling air source to the precooling air intake pipe or the purge pipe.

[0006] Furthermore, the precooling exhaust pipe is connected to a precooling exhaust valve.

[0007] Furthermore, the first-stage refrigeration section of the refrigerator is equipped with a first-stage thermometer, and the second-stage refrigeration section is equipped with a second-stage thermometer; a temperature connector is provided on the neck section, and the first-stage thermometer and the second-stage thermometer are connected to the temperature connector by wires.

[0008] Furthermore, it also includes a control box, which is electrically connected to the temperature connector, the three-way solenoid valve, the precooling exhaust valve, and the refrigeration unit, and is used to control the start and stop of the precooling structure and the operation of the refrigeration unit based on the temperature feedback from the primary thermometer and the secondary thermometer.

[0009] Furthermore, an exhaust valve is also provided on the neck section for opening when the pump body is reheated and vented.

[0010] Furthermore, the vacuum shroud also includes an upper flange, which is disposed on the upper circumferential end face of the enclosing section for connecting to an external vacuum chamber.

[0011] Furthermore, the vacuum shroud also includes a lower flange, which is disposed on the circumferential end face of the neck section, and the refrigeration unit includes a refrigeration unit flange, which is connected to the lower flange.

[0012] Furthermore, the precooling intake pipe and the precooling exhaust pipe are connected to the precooling pipe bank via a clamp.

[0013] Beneficial effects: Based on the structure of the cryogenic vacuum pump described above, a cryogenic or room-temperature inert gas is introduced into the precooling inlet pipe. The high-temperature gas in the chamber connected to the pump flows through the precooling pipe and its temperature decreases after heat exchange. After contacting the cryogenic baffle, it enters the radiation shield and is frozen into a solid state by the extremely low-temperature condensing plate assembly, thus maintaining its low temperature. This avoids direct contact between the high-temperature gas and the baffle and condensing plate assembly, which can reduce the heat load of the refrigerator, ensure the low temperature of the refrigerator to effectively freeze the gas, and reduce the possibility of the cryogenic vacuum pump failing due to excessive temperature. Attached Figure Description

[0014] Figure 1 This is a side view of a cryogenic vacuum pump structure with inlet precooling according to the present invention.

[0015] Figure 2 This is a top view of a cryogenic vacuum pump structure with inlet precooling according to the present invention.

[0016] Figure 3 This is a side view of another aspect of the cryogenic vacuum pump structure with inlet precooling according to the present invention.

[0017] Figure 4 for Figure 2 A sectional view along section line AA. Detailed Implementation

[0018] When in use, the cryogenic vacuum pump is connected to the chamber that needs to be evacuated, and a backing pump is required. A dry nitrogen gas source is also required. The backing pump and nitrogen gas source are not included in the cryogenic vacuum pump of this embodiment and are provided by the user.

[0019] The technical solution of the present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0020] like Figures 1-4 As shown, the cryogenic vacuum pump with pre-cooled intake air designed in this invention includes: a vacuum hood 10, a refrigerator 20, a control box 30, a radiation shield 401, a baffle 402, a condenser plate assembly 403, a three-way solenoid valve 105, a pre-cooling pipe array 107, a pre-cooling intake pipe 112, a purge pipe 111, a pre-cooling exhaust pipe 113, a pre-cooling exhaust valve 108, and an exhaust valve 110. The specific configuration is as follows: The vacuum hood 10 includes an enclosing section 101, a neck section 102, an upper flange 103, and a lower flange 109. The neck section 102 is disposed on the circumferential side of the enclosing section 101, the upper flange 103 is disposed on the circumferential upper end face of the enclosing section 101, and the lower flange 109 is disposed on the circumferential end face of the neck section 102. A temperature connector 104 and an exhaust valve 110 are disposed on the neck section 102, and a pre-cooling inlet is disposed on the circumferential surface of the enclosing section 101. The air inlet pipe 112, the purge pipe 111, and the pre-cooling exhaust pipe 113 are connected together at the other end of the pre-cooling air inlet pipe 112 and the purge pipe 111 to a three-way solenoid valve 105. The other end of the pre-cooling exhaust pipe 113 is connected to a pre-cooling exhaust valve 108. The pre-cooling air inlet pipe 112 and the pre-cooling exhaust pipe 113 pass through the enclosure section 101 and extend into the interior. The pre-cooling air inlet pipe 112 and the pre-cooling exhaust pipe 113 are connected by a pre-cooling pipe row 107 through a clamp 106.

[0021] The refrigerator 20 extends into the vacuum chamber 10 through the lower flange 109. The refrigerator 20 includes a refrigerator flange 205, a primary refrigeration section 201, and a secondary refrigeration section 202. The refrigerator flange 205 is connected to the lower flange 109. A primary thermometer 203 is arranged on the primary refrigeration section 201 and is surrounded within the neck section 102. A secondary thermometer 204 is arranged on the secondary refrigeration section 202 and is surrounded within the enclosure section 101. The primary thermometer 203 and the secondary thermometer 204 are connected to a temperature connector 104 via thin wires (the thin wires are not shown in the figure). A radiation shield 401 is connected to the primary refrigeration section 201 and conducts heat, and is surrounded within the enclosure section 101. A baffle 402 is connected to the top of the radiation shield 401. The precooling pipe array 107 is located above the baffle 402. The condenser plate assembly 403 is connected to the secondary refrigeration section 202 and is surrounded within the space enclosed by the radiation shield 401 and the baffle 402.

[0022] The control box 30 is installed and fixed on the refrigeration unit 20, and is connected to the temperature connector 104, the three-way solenoid valve 105, the pre-cooling exhaust valve 108, the exhaust valve 110 and the refrigeration unit 20 (the cables are not shown in the figure) via cables. The control box 30 can control the opening and closing of the valves, the operation and stopping of the refrigeration unit 20, and the acquisition of the values ​​of the primary thermometer 203 and the secondary thermometer 204.

[0023] The present invention relates to a cryogenic vacuum pump with pre-cooled air intake. The cryogenic vacuum pump is connected to a vacuum chamber. During operation, the refrigerator 20 operates to lower the primary cooling section 201, the radiation shield 401 and the baffle 402 to the primary operating temperature Tg1, and lowers the secondary cooling section 202 and the condenser plate assembly 403 to the secondary operating temperature Tg2. The control box 30 collects the temperature T1 fed back by the primary thermometer 203 and the temperature T2 fed back by the secondary thermometer in real time through the temperature connector 104.

[0024] Once the temperature of the cryogenic vacuum pump drops to Tg1 and Tg2, it can effectively evacuate the gases generated or introduced into the vacuum chamber, such as nitrogen and argon. Gas molecules flow through the pre-cooling tube 107 and collide with the baffle 402. After being cooled by the baffle 402, they enter the space enclosed by the radiation shield 401 and the baffle 402, and are eventually frozen by the condenser assembly 403 at Tg2 temperature, forming a solid frozen layer on its surface. The cooling capacity generated by the refrigerator 20 during operation is used to maintain the low temperature of the pump's internal components and to lower the temperature of the gas molecules, causing them to freeze. The gas temperature greatly affects T1 and T2. For the same gas molecular weight, if the gas temperature is at or below room temperature, the cooling capacity of the refrigerator 20 is sufficient. The condenser assembly 403 continues to freeze the gas, and the frozen layer on its surface gradually increases. Upon contact with the radiation shield 401 or the baffle 402, the frozen layer in contact cannot continue to freeze, leading to an increase in pressure. Only then will the cryogenic vacuum pump fail.

[0025] High-temperature heat sources exist within some vacuum chambers, leading to high gas temperatures. The heat load from this high-temperature gas entering the pump is significant, potentially exceeding the cooling capacity of the refrigerator 20. This causes T1 and T2 to rise rapidly, exceeding the effective freezing gas temperature and causing the cryogenic vacuum pump to fail, preventing further gas freezing. To address this, the present invention designs a pre-cooling structure including a three-way solenoid valve 105, a pre-cooling inlet pipe 112, a pre-cooling pipe array 107, a pre-cooling exhaust pipe 113, and a pre-cooling exhaust valve 108. The three-way solenoid valve 105 connects to a pre-cooling gas source at or below room temperature. When the control box 30 detects a rapid increase in T1 and T2 temperatures, it immediately opens the pre-cooling inlet pipe 112 side passage of the three-way solenoid valve 105 (the purge pipe 111 side passage is not open at this time) and the pre-cooling exhaust valve 108. The pre-cooled gas flows through the pre-cooling inlet pipe 112, through the pre-cooling pipe array 107 and the pre-cooling exhaust pipe 113, and is discharged through the pre-cooling exhaust valve 108. The high-temperature gas inside the pump first comes into contact with the pre-cooling pipe 107, which can effectively reduce the gas temperature. Then, the gas molecules come into contact with the baffle 402 and are frozen by the condenser plate assembly 403. The addition of the pre-cooling structure can effectively reduce the temperature of the gas entering the pump, reduce the heat load on the refrigerator 20, and ensure the temperatures of T1 and T2. It can continuously and effectively freeze the gas until the freezing layer comes into contact with the component at temperature T1.

[0026] When the frozen layer on the surface of the condenser plate assembly 403 grows to the point of contacting the T1 temperature, the cryogenic vacuum pump needs to be reheated to allow the frozen layer to vaporize and be discharged from the pump before it can be cooled and used again. When the cryogenic vacuum pump starts to reheat, the refrigerator 20 stops running, the control box 30 closes the precooling inlet pipe 112 side passage and the precooling exhaust valve 108 of the three-way solenoid valve 105, and opens the purge pipe 111 side passage. At this time, the gas from the precooling gas source directly enters the pump through the purge pipe 111, heating the frozen layer and causing it to vaporize. A large amount of gas inside the pump is discharged from the pump through the exhaust valve 110. The exhaust valve 110 can automatically open (by being pushed open by pressure) after the pressure reaches a certain value.

Claims

1. A cryogenic vacuum pump structure with inlet pre-cooling, characterized in that, The system includes a vacuum chamber (10), a refrigerator (20), and a precooling structure. The vacuum chamber (10) includes an enclosing section (101) and a neck section (102). The neck section (102) is located on the circumferential side of the enclosing section (101). A radiation shield (401) is installed inside the enclosing section (101). A baffle (402) is connected to the top of the radiation shield (401). A refrigerator is installed within the space enclosed by the radiation shield (401) and the baffle (402). Condensing plate assembly (403); The refrigerator (20) includes a primary refrigeration section (201) and a secondary refrigeration section (202), the primary refrigeration section (201) is surrounded within a neck section (102), the secondary refrigeration section (202) is surrounded within an enclosure section (101), the radiation shield (401) is connected to the primary refrigeration section (201) and conducts heat, and the condensing plate assembly (403) is connected to the secondary refrigeration section (202); The precooling structure includes a precooling inlet pipe (112), a precooling exhaust pipe (113) disposed on the enclosure section (101), and a precooling pipe array (107) disposed above the baffle (402); the precooling inlet pipe (112) and the precooling exhaust pipe (113) pass through the enclosure section (101) and are respectively connected to both ends of the precooling pipe array (107); an external precooling gas source is connected to the precooling inlet pipe (112), so that the precooling gas flows through the precooling inlet pipe (112) through the precooling pipe array (107) and is discharged from the precooling exhaust pipe (113); the high-temperature gas entering the vacuum hood (10) flows through the precooling pipe array (107) and is precooled and cooled before contacting the baffle (402), and is then frozen by the condenser plate assembly (403).

2. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 1, characterized in that, The enclosing section (101) is also provided with a purge pipe (111). The precooling air inlet pipe (112) and the purge pipe (111) are connected to a three-way solenoid valve (105). The three-way solenoid valve (105) is used to selectively connect the precooling air source to the precooling air inlet pipe (112) or the purge pipe (111).

3. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 2, characterized in that, The precooling exhaust pipe (113) is connected to a precooling exhaust valve (108).

4. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 3, characterized in that, The refrigerator (20) is equipped with a primary thermometer (203) on the primary refrigeration section (201) and a secondary thermometer (204) on the secondary refrigeration section (202); a temperature connector (104) is provided on the neck section (102), and the primary thermometer (203) and the secondary thermometer (204) are connected to the temperature connector (104) by wires.

5. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 4, characterized in that, It also includes a control box (30), which is electrically connected to the temperature connector (104), the three-way solenoid valve (105), the precooling exhaust valve (108), and the refrigerator (20), and is used to control the start and stop of the precooling structure and the operation of the refrigerator (20) based on the temperature feedback from the primary thermometer (203) and the secondary thermometer (204).

6. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 1, characterized in that, The neck section (102) is also equipped with an exhaust valve (110) for opening when the pump body is reheated and vented.

7. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 1, characterized in that, The vacuum shroud (10) also includes an upper flange (103), which is disposed on the upper circumferential surface of the enclosing section (101) for connecting to an external vacuum chamber.

8. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 1, characterized in that, The vacuum hood (10) also includes a lower flange (109), which is disposed on the circumferential end face of the neck section (102). The refrigerator (20) includes a refrigerator flange (205), which is connected to the lower flange (109).

9. The cryogenic vacuum pump structure with inlet pre-cooling according to claim 1, characterized in that, The precooling intake pipe (112) and the precooling exhaust pipe (113) are connected to the precooling pipe bank (107) via a clamp (106).

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