Low-temperature pump baking regeneration system, baking method and regeneration method

Abstract

The invention relates to the technical field of cryopumps, in particular to a cryopump baking regeneration system, a baking method and a regeneration method.The cryopump baking regeneration system comprises a pump shell, a baking device, a refrigerating device, a nitrogen purging device and an air extractor, a pump cavity is formed in the pump shell, and a first-stage cold array and a second-stage cold array are arranged in the pump cavity; the baking device is arranged on the periphery of the pump shell and used for heating the pump cavity. The refrigerating device is connected with the first-stage cold array and the second-stage cold array and used for refrigerating the first-stage cold array and the second-stage cold array, so that the temperature of the first-stage cold array and the temperature of the second-stage cold array are lower than the preset temperature. The nitrogen purging device communicates with the pump cavity and is used for introducing hot nitrogen into the pump cavity; the air extractor is communicated with the pump cavity and is used for exhausting air in the pump cavity; through cooperation of the baking device and the refrigerating device, parts, except for refrigerating mechanisms with poor temperature resistance, such as a primary cold array and a secondary cold array, in the low-temperature pump can reach a high temperature, so that the low-temperature pump can discharge air more quickly and more thoroughly, and the low-temperature pump can reach a better vacuum degree.

Description

Technical Field

[0001] The present application relates to the technical field of cryopumps, and in particular to a cryopump baking regeneration system, baking method and regeneration method. Background Art

[0002] The ultimate pressure of a standard cryogenic vacuum pump is usually 10 -7 Pa-10 -8 Pa. To achieve a better vacuum degree, the cryopump must be baked. However, the low-temperature refrigerator (usually a two-stage GM refrigerator) serving as the cold source of the cryopump has poor temperature resistance, and its baking temperature must not exceed about 70°C. At such a temperature, the exhaust efficiency and sufficiency inside the cryopump are insufficient, making it difficult to reach the ultimate vacuum degree. Summary of the invention

[0003] The present application provides a low temperature pump baking regeneration system, baking method and regeneration method, which are used to solve the problem in the prior art that when baking at a temperature below 70°C, the gas outlet efficiency and sufficiency inside the low temperature pump are insufficient, and it is difficult to reach the ultimate vacuum degree.

[0004] On the one hand, the present application provides a low temperature pump bake-out regeneration system, comprising:

[0005] A pump casing, wherein a pump chamber is provided in the pump casing, and a primary cooling array and a secondary cooling array are arranged in the pump chamber;

[0006] A baking device, arranged around the pump casing, for heating the pump cavity;

[0007] The refrigeration device is connected to the primary cooling array and the secondary cooling array respectively, and is used to refrigerate the primary cooling array and the secondary cooling array so that the temperature of the primary cooling array and the secondary cooling array is lower than a preset temperature;

[0008] A nitrogen purge device is connected to the pump chamber and is used to introduce hot nitrogen into the pump chamber;

[0009] The air extraction device is connected to the pump chamber and is used for exhausting the gas in the pump chamber.

[0010] In a possible design, the first-stage cooling array includes a first-stage cooling screen and a baffle, the baffle is arranged at the opening of the pump casing, and the first-stage cooling screen is arranged close to the inner wall of the pump casing;

[0011] The secondary cold array comprises a secondary cold screen and an adsorption layer. The secondary cold screen is arranged near the center of the pump cavity, and the adsorption layer is arranged on a side of the secondary cold screen away from the primary cold screen.

[0012] In one possible design, the baking device includes:

[0013] A heating cover, which is arranged around the outer circumference of the pump housing;

[0014] A power regulator is electrically connected to the heating cover;

[0015] The first temperature sensor is arranged on the pump housing and is electrically connected to the power regulator.

[0016] In one possible design, the refrigeration unit includes:

[0017] Helium compressor;

[0018] A refrigerator is connected to the helium compressor through a high-pressure helium tube and a low-pressure helium tube, respectively, and is used to cool the primary cooling array and the secondary cooling array;

[0019] The frequency conversion unit is electrically connected to the helium compressor and the refrigerator and is used to change the output frequency of the refrigerator and the helium compressor.

[0020] In one possible design, the nitrogen purge device includes:

[0021] a gas supply pipeline, connected to a nitrogen source;

[0022] A heater, disposed on the gas supply pipeline, for heating the nitrogen flowing through the gas supply pipeline;

[0023] Solenoid valve, installed on the gas supply pipeline;

[0024] The purge pipeline is arranged in the pump cavity and is communicated with the air supply pipeline. The purge end of the purge pipeline extends to the secondary cooling array.

[0025] In a possible design, the air extraction device includes a roughing pump, an exhaust pipe and a roughing valve. One end of the exhaust pipe is connected to the pump chamber, and the other end is connected to the roughing pump. The roughing valve is installed on the exhaust pipe.

[0026] In one possible design, it also includes:

[0027] A primary heating unit is arranged on the primary cooling array and is used to heat the primary cooling array;

[0028] The secondary heating unit is arranged on the secondary cooling array and is used for heating the secondary cooling array.

[0029] In a possible design, the primary heating unit and the secondary heating unit respectively include:

[0030] A heating wire, wherein a heat-conducting insulating layer is provided on the heating wire;

[0031] The second temperature sensor is arranged on the first-level cooling array / second-level cooling array;

[0032] The heating switch is electrically connected to the second temperature sensor, and the heating switch is also connected in series with the heating wire and the baking device respectively.

[0033] On the other hand, the present application also provides a cryopump baking method, using the cryopump baking regeneration system as described above, the method comprising:

[0034] Start the vacuum device to make the pressure in the pump chamber lower than 10 -4 Pa;

[0035] Start the primary heating unit and the secondary heating unit to keep the temperature of the primary cooling array and the secondary cooling array at 60℃-70℃;

[0036] Start the baking device to keep the temperature of the pump casing between 60℃-70℃, and bake it for a certain period of time to discharge the water vapor from the first and second cooling arrays;

[0037] Start the refrigeration device and make it run under the set low frequency and low power conditions;

[0038] Increase the baking temperature of the baking device to maintain the pump casing temperature at 150℃-200℃, and maintain the temperature of the first-level cooling array and the second-level cooling array at 60℃-70℃ by adjusting the operating frequency of the refrigeration device and the output power of the first-level heating unit and the second-level heating unit.

[0039] On the other hand, the present application also provides a cryopump regeneration method, using the cryopump bake-out regeneration system as described above, the method comprising:

[0040] Turn on the nitrogen purge device to allow hot nitrogen to continuously enter the pump chamber;

[0041] Start the baking device, set the temperature to 150℃-200℃, and heat the pump casing;

[0042] When the pressure in the pump cavity returns to nearly 1 atmospheric pressure, the vacuum device is turned on to extract hot nitrogen to the outside, and the hot nitrogen is used to reheat the first and second cooling arrays;

[0043] During the temperature recovery process, adjust the temperature of the baking device so that the temperature of the second-stage cooling array is always higher than that of the first-stage cooling array;

[0044] When the temperature of the first-stage cold array is restored to nearly 10°C, the baking temperature of the baking device is changed to 60°C-70°C; when the temperature of the first-stage cold array is restored to nearly 60°C, the introduction of hot nitrogen is stopped; the air pressure of the pump chamber is pumped down to less than 1Pa through the exhaust device;

[0045] After baking and pumping for a period of time, turn off the pumping device; if the pressure rise rate in the pump chamber is lower than the nominal value of the cryogenic pump, turn off the baking device;

[0046] Start the cryopump to make the temperature of the secondary cooling array lower than 15K, and the cryopump regeneration is completed.

[0047] The beneficial effects of this application are as follows:

[0048] The low-temperature pump baking regeneration system of the present application is provided with a baking device outside the pump casing. During the baking process, the refrigeration device is used to perform low-frequency refrigeration on the first-level cold array and the second-level cold array, so that the temperature of the first-level cold array and the second-level cold array is lower than the preset temperature, and the baking temperature of the low-temperature pump cavity and the heat sink can reach 150°C-200°C. At the same time, the temperature of the first-level cold array and the second-level cold array of the low-temperature pump does not exceed 70°C. Therefore, during the baking process, the components in the low-temperature pump except for the refrigeration mechanisms with poor temperature resistance such as the first-level cold array and the second-level cold array can reach a higher temperature, which is beneficial to improve the exhaust efficiency of the low-temperature pump, make the exhaust of the low-temperature pump more thorough, and thus achieve a better vacuum degree.

[0049] The low-temperature pump baking method of the present application can accurately control the temperature of the first-level cooling array and the second-level cooling array by cooperating with the first-level heating unit, the second-level heating unit and the baking device, so that the pump casing of the low-temperature pump can reach a higher baking temperature, and the low-temperature pump can achieve a better vacuum degree.

[0050] The cryopump regeneration method of the present application can dilute the process gas and promote the release of the process gas from the adsorption layer by cooperating with the baking device and the nitrogen purge device; by making the temperature recovery speed of the secondary cold array faster than that of the primary cold array, it can avoid the water vapor of the primary cold array from condensing again on the secondary cold array. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 A schematic diagram of the structure of a low temperature pump baking regeneration system provided in an embodiment of the present application;

[0053] Figure 2 A schematic diagram of the structure of a baking device of a low temperature pump baking regeneration system provided in an embodiment of the present application;

[0054] Figure 3 A schematic diagram of the structure of a heating unit of a low temperature pump bake-out regeneration system provided in an embodiment of the present application.

[0055] Reference numerals:

[0056] 100, pump housing; 110, pump chamber; 210, primary cooling array; 211, primary cooling screen; 212, baffle; 220, secondary cooling array; 221, secondary cooling screen; 222, adsorption layer; 300, baking device; 310, heating cover; 410, helium compressor; 420, refrigerator; 430, frequency conversion unit; 500, nitrogen purge device; 510, gas supply pipeline; 520, heater; 530, solenoid valve; 540, purge pipeline; 600, exhaust device; 610, roughing pump; 620, exhaust pipeline; 630, roughing valve; 700, primary heating unit; 710, heating wire; 720, second temperature sensor; 800, secondary heating unit; 910, mounting ring groove; 920, adjusting screw; 930, first clamping wheel; 940, second clamping wheel; 950, spring. DETAILED DESCRIPTION

[0057] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0058] Combine the following Figure 1-Figure 2, describes the low-temperature pump baking regeneration system provided in the embodiment of the present application, including a pump housing 100, a baking device 300, a refrigeration device, a nitrogen purge device 500 and an exhaust device 600. The pump housing 100 is the structural body of the low-temperature pump. In order to meet the requirements of ultra-high vacuum applications, the interface flange of the pump housing 100 is an all-metal knife-edge flange. The pump housing 100 is cylindrical and has a pump cavity 110 in the pump housing 100. A primary cooling array 210 and a secondary cooling array 220 are arranged in the pump cavity 110. The refrigeration device is respectively connected to the primary cooling array 210 and the secondary cooling array 220 for cooling the primary cooling array 210 and the secondary cooling array 220. Specifically, the first-stage cold array 210 includes a first-stage cold screen 211 and a baffle 212. The baffle 212 is arranged at an opening at one end of the pump housing 100. The structure of the baffle 212 adopts a shutter-type heat shielding structure. The baffle 212 forms the first thermal barrier between the pump chamber 110 and the external environment; the first-stage cold screen 211 is cylindrical and is arranged close to the inner wall of the pump housing 100. When the cryopump is working normally, the temperature of the first-stage cold screen 211 is between 30K and 150K. The gas entering from the opening of the pump housing 100 passes through the baffle 212 and reaches the first-stage cold screen 211. Under the condensation effect of the low-temperature first-stage cold screen 211, water vapor is generated on the first-stage cold screen 211. Condensation occurs; the secondary cold array 220 includes a secondary cold screen 221 and an adsorption layer 222. The secondary cold screen 221 is cylindrical and is arranged near the center of the pump chamber 110. The adsorption layer 222 is arranged on the side of the secondary cold screen 221 away from the primary cold screen 211. The adsorption layer 222 adopts an activated carbon layer. When the cryopump works normally, the temperature of the secondary cold array 220 is lower than that of the primary cold array 210. Except for water vapor, the remaining gases continue to flow to the secondary cold screen 221 and the adsorption layer 222 with a lower temperature after passing through the baffle 212 and the primary cold screen 211. In a low temperature environment, the gas is adsorbed by the adsorption layer 222, so that the external environment reaches a certain vacuum degree.

[0059] In order to enable the external environment to achieve a better vacuum degree, in the embodiment of the present application, a baking device 300 is arranged around the pump housing 100, which can provide a baking temperature of not less than 200°C for the pump housing 100 of the cryogenic pump as a whole, and is used to bake the pump chamber 110 for a certain period of time before the vacuum pump works, so that the pump chamber 110 is heated up, thereby increasing the molecular kinetic energy by heating so that the gas molecules released from the surface or inside of the vacuum pump material can be fully and quickly discharged, thereby reducing the gas outgassing rate of the vacuum pump. Specifically, the baking device 300 includes a heating hood 310, a power regulator and a first temperature sensor. The heating hood 310 is arranged around the outer periphery of the pump casing 100. A resistance wire is arranged on the side of the heating hood 310 close to the pump casing 100 for heating the pump casing 100. The power regulator is electrically connected to the heating hood 310. The first temperature sensor is arranged on the pump casing 100 and is electrically connected to the power regulator. The power regulator adjusts the output power of the heating hood 310 according to the temperature of the pump casing 100 obtained by the first temperature sensor, thereby ensuring that the temperature of the pump casing 100 is within a certain range.

[0060] Taking into account that the refrigeration machines 420 such as the primary cold array 210 and the secondary cold array 220 are not heat-resistant, when the baking device 300 is working, the primary cold array 210 and the secondary cold array 220 are cooled by the refrigeration device so that the temperatures of the primary cold array 210 and the secondary cold array 220 are lower than the preset temperature. Generally, maintaining the temperatures of the primary cold array 210 and the secondary cold array 220 below 70°C will not damage their performance.

[0061] Specifically, the refrigeration device includes a helium compressor 410, a refrigerator 420 and a frequency conversion unit 430. The refrigerator 420 is connected to the helium compressor 410 through a high-pressure helium tube, a low-pressure helium tube and a cable. The refrigerator 420 is usually a two-stage GM refrigerator 420. The first-stage cold array 210 is connected to the first-stage cold head of the refrigerator 420, and the second-stage cold array 220 is connected to the second-stage cold head of the refrigerator 420. The refrigerator 420 is used to cool the first-stage cold array 210 and the second-stage cold array 220; the frequency conversion unit 430 and the helium compressor 410 and refrigerator 420 are electrically connected, and the frequency conversion unit 430 is used to change the output frequency of the refrigerator 420 and the helium compressor 410; the frequency conversion unit 430 adopts a frequency converter, and the frequency converter adjusts the voltage and frequency of the output power supply by the opening and closing of the internal IGBT, and provides the power supply voltage required by the motor according to the actual needs of the motor, thereby achieving the purpose of energy saving and speed regulation; usually the frequency conversion unit 430 is located in the helium compressor 410, and the frequency conversion unit 430 can also be independently arranged in the refrigerator 420 and the helium compressor 410; the function of the frequency conversion unit 430 is to: change the rotation frequency of the scroll compressor in the helium compressor 410 and the frequency of the motor of the refrigerator 420, thereby changing the movement frequency of the excluder in the refrigerator 420, wherein the scroll compressor can be AC ​​frequency conversion or DC frequency conversion; the motor of the refrigerator 420 can be an AC motor or a DC motor; it can be a rotary motor or a linear motor; so that the power of the helium compressor 410 and the refrigerator 420 are matched, so that the power and The temperatures of the primary cooling array 210 and the secondary cooling array 220 are matched, and the energy consumption is effectively reduced. For example, if the temperatures of the primary cooling array 210 and the secondary cooling array 220 are low, the frequencies of the helium compressor 410 and the refrigerator 420 are reduced. If the temperatures of the primary cooling array 210 and the secondary cooling array 220 are high, the frequencies of the helium compressor 410 and the refrigerator 420 are increased, so that the temperature of the pump housing 100 can reach 150°C-200°C, while ensuring that the temperatures of the primary cooling array 210 and the secondary cooling array 220 are maintained below 70 degrees.

[0062] Reference Figure 2As shown, in some specific embodiments, a mounting ring groove 910 is provided at the end of the pump housing 100, and the heating cover 310 can be detachably installed in the mounting ring groove 910, so that the heating cover 310 can be quickly installed and disassembled on the pump housing 100, and can be easily adapted to the use of different working conditions of the cryogenic pump. Specifically, the heating cover 310 is provided with a threaded hole, and an adjusting screw 920 is threadedly installed in the threaded hole. A first clamping wheel 930 is fixedly installed at the end of the adjusting screw 920, and a second clamping wheel 940 is parallel to the first clamping wheel 930. The first clamping wheel 930 and the second clamping wheel 940 are connected through a spring 950. The second clamping wheel 940 is pressed toward the first clamping wheel 930 along the length direction of the spring 950, so that the spring 950 can be compressed. At this time, the first clamping wheel 930 and the second clamping wheel 940 are integrally inserted into the mounting ring groove 910. Under the action of the compression elastic force of the spring 950 and the weight of the heating cover 310 itself, the heating cover 310 can be quickly and firmly installed on the pump. shell 100; by adjusting the position of the heating hood 310 on the adjusting screw 920, the distance between the heating hood 310 and the pump shell 100 is adjusted, so that the heating hood 310 can be moved away from or close to the pump shell 100 according to the temperature of the pump shell 100 obtained by the first temperature sensor; in other specific embodiments, the adjusting screw 920 is connected to the adjusting motor, and the adjusting motor is respectively connected to the first temperature sensor and the displacement sensor signal. The adjusting motor drives the adjusting screw 920 to rotate according to the temperature of the pump shell 100 obtained by the first temperature sensor, thereby driving the heating hood 310 away from or close to the pump shell 100, and the adjusting motor stops rotating according to the feedback of the displacement sensor. In other specific embodiments, the heating hood 310 includes a plurality of heating hoods 310 which are distributed in a ring shape to form a cylinder. Each heating hood 310 is threadedly connected with an adjusting screw 920. By adjusting the position of each heating hood 310 on the corresponding adjusting screw 920, the size of the cylinder formed by all the heating hoods 310 can be adjusted to adapt to pump housings 100 of different diameters.

[0063] Reference Figure 1 , Figure 3As shown, in some embodiments provided in the present application, the low temperature pump baking regeneration system further includes a primary heating unit 700 and a secondary heating unit 800. The primary heating unit 700 is arranged on the primary cold array 210 for heating the primary cold array 210; the secondary heating unit 800 is arranged on the secondary cold array 220 for heating the secondary cold array 220. In this way, the primary cold array 210 and the secondary cold array 220 can be heated when the refrigerator 420 is working, so as to prevent the primary cold array 210 and the secondary cold array 220 from being too low in temperature. Specifically, the primary heating unit 700 and the secondary heating unit 800 respectively include a heating wire 710, a second temperature sensor 720 and a heating switch. The heating wire 710, the second temperature sensor 720 and the heating switch are all encapsulated in a metal block. The metal block is supported by metals such as copper and aluminum with high thermal conductivity, which is conducive to heat conduction. A heat conductive insulating layer is provided on the heating wire 710 to ensure the heating effect. The second temperature sensor 720 is arranged on the first-level cold array 210 / the second-level cold array 220. Specifically, the second temperature sensor 720 is arranged on the first-level cold head and the second-level cold head of the refrigerator 420; the heating switch is electrically connected to the second temperature sensor 720, and the heating switch is also connected in series with the heating wire 710 and the baking device 300 respectively. When the second temperature sensor 720 detects that the temperature reaches the set temperature, such as 70°C, the temperature switch can disconnect the circuit, for example, disconnect the heating wire 710 or disconnect the circuit of the baking device 300, thereby avoiding overheating of the cold head of the refrigerator 420.

[0064] Reference Figure 1 As shown, in some embodiments provided in the present application, the low temperature pump baking regeneration system also includes a nitrogen purge device 500, which is connected to the pump chamber 110, and the nitrogen purge device 500 is used to introduce hot nitrogen into the pump chamber 110; specifically, the nitrogen purge device 500 includes a gas supply pipeline 510, a heater 520, a solenoid valve 530 and a purge pipeline 540, and the gas supply pipeline 510 is connected to the nitrogen source; the heater 520 is arranged on the gas supply pipeline 510, and is used to heat the nitrogen flowing through the gas supply pipeline 510; the solenoid valve 530 is installed on the gas supply pipeline 510, and the solenoid valve 530 adopts an all-metal solenoid valve 530, which can achieve high vacuum sealing and withstand 150°C-200°C baking; the purge pipe 540 is arranged in the pump chamber 110 and is connected with the air supply pipe 510. The purge end of the purge pipe 540 extends to the secondary cold array 220. In this way, within a certain air supply pressure range, the nitrogen purge device 500 can provide dry pure nitrogen at about 60°C-70°C, and directly purge the dry hot nitrogen to the secondary cold array 220 in the pump chamber 110, so as to blow it to the adsorption layer 222 of the secondary cold array 220, promote the discharge of water vapor and other gases in the adsorption layer 222, and can locally increase the temperature of the secondary cold array 220, ensure that the temperature of the secondary cold array 220 is higher than that of the primary cold array 210, and prevent the water vapor of the primary cold array 210 from re-condensing on the secondary cold array 220.

[0065] The air extraction device 600 is connected to the pump chamber 110 and is used to discharge the gas in the pump chamber 110. Specifically, the air extraction device 600 includes a roughing pump 610, an exhaust pipe 620 and a roughing valve 630. One end of the exhaust pipe 620 is connected to the pump chamber 110, and the other end is connected to the roughing pump 610. The roughing valve 630 is installed on the exhaust pipe 620. The roughing pump 610 is a dry pump such as a screw pump, a vortex pump, a claw pump, a multi-stage Roots pump, or a unit composed of the above-mentioned dry pump and the Roots pump, and the above-mentioned dry pump or unit is further combined with a molecular pump to form a unit, and the roughing pump 610 as a cryopump is used to discharge the gas in the pump chamber 110. The pressure in the pump chamber 110 is detected by a capacitive film gauge to detect the precise pressure changes in the pump chamber 110 in real time during the regeneration or air extraction process.

[0066] On the other hand, the present application also provides a cryopump baking method, using the cryopump baking regeneration system in the above embodiment, the method comprising:

[0067] Start the vacuum device 600 to make the pressure of the pump chamber 110 lower than 10 -4 Pa;

[0068] Start the primary heating unit 700 and the secondary heating unit 800 to keep the temperature of the primary cooling array 210 and the secondary cooling array 220 at 60° C.-70° C.;

[0069] Start the baking device 300 to keep the temperature of the pump housing 100 between 60° C. and 70° C. and bake for a certain period of time to discharge the moisture in the primary cooling array 210 and the secondary cooling array 220;

[0070] Start the refrigeration device and make it run under the set low frequency and low power conditions;

[0071] The baking temperature of the baking device 300 is increased to maintain the temperature of the pump housing 100 at 150°C-200°C, and the temperature of the first-level cooling array 210 and the second-level cooling array 220 is maintained at 60°C-70°C by adjusting the operating frequency of the refrigeration device and the output power of the first-level heating unit 700 and the second-level heating unit 800.

[0072] When the low temperature pump baking method of the present application is used to carry out ultra-high vacuum baking, the following beneficial effects are achieved:

[0073] First, by providing a frequency conversion unit 430 in the helium compressor 410 and the refrigerator 420, the refrigerator 420 can be operated at a low frequency, so that the baking process that does not require too high a cooling power can be operated economically;

[0074] Second, the frequency conversion unit 430 and the temperature control unit can cooperate to accurately control the temperature of the first-stage cooling array 210 and the second-stage cooling array 220, so that the pump housing 100 of the cryopump can reach a higher baking temperature;

[0075] Third, the baking stage is set as a two-stage baking form, in which the baking at 60℃-70℃ is mainly used to remove moisture. During this stage of baking, there is no need to turn on the cryogenic pump; while the baking at 150℃-200℃ can accelerate the removal of moisture, hydrogen and other gases, shorten the baking time, and improve the efficiency of baking degassing.

[0076] On the other hand, the present application also provides a cryopump regeneration method, using the cryopump bake-out regeneration system in the above embodiment, the method comprising:

[0077] Turn on the nitrogen purge device 500 to allow hot nitrogen to continuously enter the pump chamber 110;

[0078] Start the baking device 300, set the temperature to 150°C-200°C, and heat the pump housing 100;

[0079] When the pressure in the pump chamber 110 is restored to nearly 1 atmospheric pressure, the exhaust device 600 is turned on to extract the hot nitrogen gas outward, and the hot nitrogen gas is used to reheat the first-stage cooling array 210 and the second-stage cooling array 220;

[0080] During the temperature recovery process, the temperature of the baking device 300 is adjusted so that the temperature of the secondary cooling array 220 is always higher than the temperature of the primary cooling array 210;

[0081] When the temperature of the first-stage cooling array 210 is restored to approximately 10°C, the baking temperature of the baking device 300 is changed to 60°C-70°C; when the temperature of the first-stage cooling array 210 is restored to approximately 60°C, the introduction of hot nitrogen is stopped; the air pressure of the pump chamber 110 is pumped to below 1Pa through the exhaust device 600;

[0082] After baking and exhausting for a period of time, the exhaust device 600 is turned off; if the pressure rise rate in the pump chamber 110 is lower than the nominal value of the cryopump, the baking device 300 is turned off;

[0083] The cryopump is started to make the temperature of the secondary cooling array 220 lower than 15K, and the cryopump regeneration is completed.

[0084] When the cryopump regeneration method of the present application is used to regenerate the cryopump, the following beneficial effects are achieved:

[0085] First, the matching of the external baking device 300 and the nitrogen purge device 500 can prevent the temperature of the pump housing 100 from being too low, which affects the use of peripheral electronic components. If there is no external baking device 300, when hot nitrogen is introduced, as the pressure rises, the heat exchange mode inside the cryopump gradually changes from radiation heat exchange to convection heat exchange, and the heat exchange capacity of the latter is much greater than that of radiation heat exchange, which may cause the coldness of the first-level cold array 210 and the second-level cold array 220 with extremely low temperatures to not be taken away by the hot nitrogen in time, thereby causing the temperature of the pump housing 100 to drop excessively. If the temperature of the pump housing 100 drops excessively, it may be lower than the local dew point, so that condensation occurs on the pump housing 100, which may damage the peripheral electronic components or increase the failure rate of the electronic components.

[0086] Second, the nitrogen purge device 500 intervenes when the cryopump starts to regenerate, directly heating the activated carbon layer of the secondary cold array 220 to promote gas release and dilution. In some processes, hydrogen may be used as a process gas. In this case, a large amount of hydrogen may be adsorbed in the secondary cold array 220 of the cryopump, and the hydrogen is basically adsorbed in the activated carbon attached to the inner side of the secondary cold array 220. The external nitrogen purge device 500 can be directly connected to the activated carbon of the secondary cold array 220, which can directly promote the release of hydrogen. Nitrogen, as an inert gas, can also effectively reduce the concentration of released hydrogen, thereby reducing safety risks. On the other hand, the direct purge of hot nitrogen will make the temperature recovery speed of the secondary cold array 220 faster than that of the primary cold array 210, avoiding the water vapor of the primary cold array 210 from condensing again on the secondary cold array 220. Third, in the initial stage of ultra-high vacuum baking, the discharge speed of water vapor in the secondary cold array 220 can be increased, and the gas adsorbed by the metal layer in the cryopump can be replaced, making subsequent exhaust and limit acquisition easier.

[0087] Third, in some processes, water vapor may be introduced as process gas, so that the cryopump may condense a large amount of water on the first-stage cold array 210. During the regeneration process, as the temperature and air pressure increase, the water vapor will liquefy in large quantities and flow to the bottom of the cryopump. Liquid water is obviously harmful to the cryopump, which may cause the black coating of the cryopump heat sink to fall off, and the high humidity environment may cause damage to the electronic components in the pump, etc., and the removal of a large amount of water vapor may waste a lot of time. The two-stage regeneration process of the present application first uses a baking device 300 to bake the pump housing 100, which can make the water that falls into the pump housing 100 evaporate quickly, so that it is directly taken away by hot nitrogen or pumped away by the roughing pump 610; the inert hot nitrogen and water vapor mixed can effectively reduce the partial pressure of water vapor, so that the dryness of the water vapor at the exhaust port of the roughing pump 610 is not too high, and the nitrogen can effectively take the water vapor out of the pump, thereby increasing the life of the roughing pump 610.

[0088] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0089] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0090] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0091] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0092] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A low temperature pump bake-out regeneration system, characterized in that: include: A pump casing, wherein a pump cavity is provided in the pump casing, and a primary cooling array and a secondary cooling array are arranged in the pump cavity; A baking device, arranged around the pump housing, for heating the pump cavity; A refrigeration device, connected to the primary cooling array and the secondary cooling array respectively, for refrigerating the primary cooling array and the secondary cooling array so that the temperature of the primary cooling array and the secondary cooling array is lower than a preset temperature; a nitrogen purge device, connected to the pump chamber and used for introducing hot nitrogen into the pump chamber; The air extraction device is connected to the pump chamber and is used for exhausting the gas in the pump chamber.

2. The cryopump bake-out regeneration system according to claim 1, characterized in that: The first-stage cooling array includes a first-stage cooling screen and a baffle, wherein the baffle is arranged at the opening of the pump housing, and the first-stage cooling screen is arranged close to the inner wall of the pump housing; The secondary cold array includes a secondary cold screen and an adsorption layer. The secondary cold screen is arranged close to the center of the pump cavity, and the adsorption layer is arranged on a side of the secondary cold screen away from the primary cold screen.

3. The cryopump bake-out regeneration system according to claim 1, characterized in that: The baking device comprises: A heating cover, the heating cover is arranged around the outer circumference of the pump housing; A power regulator, electrically connected to the heating cover; The first temperature sensor is arranged on the pump housing and is electrically connected to the power regulator.

4. The cryopump bake-out regeneration system according to claim 1, characterized in that: The refrigeration device comprises: Helium compressor; A refrigerator, connected to the helium compressor via a high-pressure helium tube and a low-pressure helium tube, respectively, for refrigerating the primary cooling array and the secondary cooling array; The frequency conversion unit is electrically connected to the helium compressor and the refrigerator, and is used to change the output frequency of the refrigerator and the helium compressor.

5. The cryopump bake-out regeneration system according to claim 1, characterized in that: The nitrogen purge device comprises: A gas supply pipeline connected to a nitrogen source; a heater, disposed on the gas supply pipeline, for heating the nitrogen flowing through the gas supply pipeline; A solenoid valve is installed on the gas supply pipeline; A purge pipeline is arranged in the pump cavity and is communicated with the air supply pipeline. The purge end of the purge pipeline extends to the secondary cooling array.

6. The cryopump bake-out regeneration system according to claim 1, characterized in that: The air extraction device comprises a roughing pump, an exhaust pipe and a roughing valve. One end of the exhaust pipe is communicated with the pump chamber, and the other end is connected to the roughing pump. The roughing valve is installed on the exhaust pipe.

7. The cryopump bake-out regeneration system according to any one of claims 1 to 6, characterized in that: Also includes: A primary heating unit, disposed on the primary cooling array, for heating the primary cooling array; The secondary heating unit is arranged on the secondary cooling array and is used for heating the secondary cooling array.

8. The cryopump bake-out regeneration system according to claim 7, characterized in that: The primary heating unit and the secondary heating unit respectively include: A heating wire, wherein a heat-conducting insulating layer is provided on the heating wire; A second temperature sensor is arranged on the first-level cooling array / the second-level cooling array; A heating switch is electrically connected to the second temperature sensor, and the heating switch is also connected in series with the heating wire and the baking device respectively.

9. A low temperature pump baking method, characterized in that: Using the cryopump bake-out regeneration system according to any one of claims 1 to 8, the method comprises: Start the vacuum device to make the pressure in the pump chamber lower than 10 -4 Pa; Start the primary heating unit and the secondary heating unit to keep the temperature of the primary cooling array and the secondary cooling array at 60℃-70℃; Start the baking device to keep the temperature of the pump casing between 60°C and 70°C, and bake for a certain period of time to discharge the water vapor of the first-level cooling array and the second-level cooling array; Start the refrigeration device and make it run under the set low frequency and low power conditions; The baking temperature of the baking device is increased to maintain the pump casing temperature at 150°C-200°C, and the temperature of the first-level cooling array and the second-level cooling array is maintained at 60°C-70°C by adjusting the operating frequency of the refrigeration device and the output power of the first-level heating unit and the second-level heating unit.

10. A cryopump regeneration method, characterized in that: Using the cryopump bake-out regeneration system according to any one of claims 1 to 8, the method comprises: Turn on the nitrogen purge device to allow hot nitrogen to continuously enter the pump chamber; Start the baking device, set the temperature to 150℃-200℃, and heat the pump casing; When the pressure in the pump chamber is restored to nearly 1 atmospheric pressure, the exhaust device is turned on to extract hot nitrogen to the outside, and the hot nitrogen is used to reheat the first-stage cold array and the second-stage cold array; During the temperature recovery process, adjusting the temperature of the baking device so that the temperature of the secondary cooling array is always higher than the temperature of the primary cooling array; When the temperature of the first-stage cooling array is restored to approximately 10°C, the baking temperature of the baking device is changed to 60°C-70°C; when the temperature of the first-stage cooling array is restored to approximately 60°C, the introduction of hot nitrogen is stopped; and the air pressure of the pump chamber is pumped to below 1Pa through the exhaust device; After baking and exhausting for a period of time, the exhaust device is turned off; if the pressure rise rate in the pump chamber is lower than the nominal value of the cryopump, the baking device is turned off; The cryopump is started to make the temperature of the secondary cooling array lower than 15K, and the cryopump regeneration is completed.

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