A small volume low power mass spectrometer vacuum system and method of establishing

Abstract

The application discloses a small-size low-power-consumption mass spectrometer vacuum system and a building method, and relates to the field of mass spectrometers.The system comprises a multi-stage decompression sampling unit, a vacuum cavity and a vacuum maintenance pump group.The vacuum maintenance pump group comprises an ion vacuum pump and a getter pump.The running current of the ion vacuum pump is used to feed back the vacuum degree of the vacuum cavity.The multi-stage decompression sampling unit comprises a membrane sampling assembly, a leak hole and a capillary tube arranged in series along the sample transmission direction.The inlet of the capillary tube is communicated with the leak hole, the outlet of the capillary tube is communicated with the vacuum cavity, and the capillary tube is arranged at the ion source end of the mass spectrometer probe, so that the sample is sent into the vacuum cavity after being subjected to step-by-step decompression and molecular screening.The application establishes ultrahigh vacuum by using a composite pump group, feeds back the vacuum degree by using the pump running current, omits an additional vacuum gauge, realizes multi-stage decompression sampling by using the capillary tube penetrating through the pump, adapts to a high-pressure scene, improves the detection sensitivity, and realizes the small size and low power consumption of the mass spectrometer vacuum system.

Description

Technical Field

[0001] This invention relates to the field of vacuum establishment technology, and in particular to a small-volume, low-power mass spectrometer vacuum system and establishment method. Background Technology

[0002] As a high-precision gas component detection device, the ion transmission efficiency, detection sensitivity, resolution, and overall lifespan of a mass spectrometer are directly determined by the stability and vacuum level of its internal vacuum environment. Only in a high vacuum environment can the scattering, collision, and charge exchange of gas molecules on the detected ions be effectively avoided, eliminating problems such as ion signal attenuation and false peak interference. At the same time, it can prevent the wear and tear of core components such as filament oxidation and detector contamination. Therefore, the vacuum system is an indispensable core component of a mass spectrometer, and its performance directly determines the overall detection capability and applicable scenarios of the mass spectrometer.

[0003] Currently, the mass spectrometer industry generally adopts a staged pumping scheme that combines a coarse pump and a high vacuum pump to establish and maintain a vacuum environment. The coarse pump is mostly a mechanical vacuum pump such as a rotary vane pump, a dry vortex pump, or a Roots pump, while the high vacuum pump is mostly a turbomolecular pump. The vacuum level is gradually increased through the staged pumping of the molecular pump group. In order to match the sample introduction requirements, the existing schemes mostly set up the sample introduction structure and the vacuum maintenance pump group independently, and the sample introduction pipeline is connected to the vacuum chamber of the mass spectrometer separately, and the vacuum maintenance pump group is arranged in a chamber layout.

[0004] However, existing technologies suffer from numerous insurmountable technical flaws, severely hindering the development of mass spectrometers towards miniaturization, portability, low power consumption, and on-site detection. First, the traditional combination of mechanical vacuum pumps and turbomolecular pumps is bulky and requires continuous high-power operation to maintain system vacuum, resulting in high overall power consumption. Furthermore, monitoring system vacuum requires an additional independent vacuum gauge and detection circuit, further increasing system size, hardware cost, and operating energy consumption, making it completely unsuitable for miniaturized and low-power applications. Second, the independently designed sample introduction structure lacks multi-stage decompression and molecular screening settings adapted to the vacuum system. In high-pressure sample introduction scenarios, the high-pressure gas flow directly into the vacuum chamber can easily cause a sudden drop in system vacuum, directly leading to distorted mass spectrometry data and detection failure. It can also cause irreversible damage to core precision components such as the vacuum maintenance pump assembly and mass spectrometer probe, making it completely unsuitable for high-pressure sample introduction applications. Third, existing vacuum maintenance pump assemblies have extremely low system integration and high component redundancy, resulting in large size and high power consumption, increasing potential failure points and maintenance costs. Furthermore, the existing independently designed sample inlet tubing lacks precise transmission path optimization, resulting in significant sample loss during transmission. This makes it impossible to accurately deliver the sample to the ion source end of the mass spectrometer probe, directly leading to a substantial decrease in the mass spectrometer's detection sensitivity and severely insufficient accuracy of the detection results. At the same time, the separate layout of the sample inlet tubing and the vacuum maintenance pump not only results in a cluttered overall system structure and a large space occupation, but also significantly increases the number of vacuum sealing points, making vacuum leakage problems highly likely and further reducing the stability and reliability of the system operation.

[0005] In summary, existing mass spectrometer vacuum systems suffer from drawbacks such as large size, high power consumption, low integration, poor adaptability to high-pressure sample introduction, insufficient detection sensitivity, poor operational stability, and easy damage to components. Summary of the Invention

[0006] The purpose of this invention is to provide a small-volume, low-power mass spectrometer vacuum system and its establishment method. Ultra-high vacuum is established through a composite pump assembly, and the vacuum level is fed back by the operating current of an ion vacuum pump, eliminating the need for an additional vacuum gauge. Multi-stage depressurization sample introduction adapts to high-pressure scenarios and improves detection sensitivity, achieving a small-volume, low-power mass spectrometer vacuum system. The specific technical solution is as follows: A small-volume, low-power mass spectrometer vacuum system includes a multi-stage depressurization sample introduction unit, a vacuum chamber, a vacuum maintenance pump assembly connected to the vacuum chamber, and a mass spectrometer probe disposed within the vacuum chamber. The vacuum maintenance pump assembly includes an ion vacuum pump and a getter pump. The getter pump is used to adsorb reactive gases within the vacuum chamber, and the ion vacuum pump is used to capture residual inert gases within the vacuum chamber. The operating current of the ion vacuum pump is used to provide feedback on the vacuum level of the vacuum chamber. The multi-stage depressurization sample introduction unit includes a membrane sample introduction component, a leak, and a capillary tube inserted through the vacuum maintenance pump assembly, arranged in series along the sample transport direction. The inlet of the capillary tube is connected to the leak, and the outlet of the capillary tube is connected to the vacuum chamber and is positioned corresponding to the ion source end of the mass spectrometer probe. This system is used to depressurize and molecularly screen the sample before sending it into the vacuum chamber.

[0007] Furthermore, it also includes a straight flange and a pre-vacuum unit installed on the straight flange. One end of the straight flange is connected to the vacuum maintaining pump group, and the other end is connected to the vacuum chamber. A capillary tube is inserted through the straight flange.

[0008] Furthermore, the pre-vacuum unit includes an angle valve and a vacuum pre-vacuum interface disposed on one side of the angle valve. The through flange includes a pipe section located in the middle, and the other side of the angle valve is connected to a side interface on the pipe section.

[0009] Furthermore, one end of the getter pump is connected to a through flange, and the other end of the getter pump is connected to an ion vacuum pump.

[0010] Furthermore, the capillary tube is coaxially inserted through the axial through hole of the vacuum maintaining pump unit. The side of the capillary tube that enters the ion vacuum pump is integrally formed with the ion vacuum pump, and the other side of the capillary tube that exits the getter pump is integrally formed with the getter pump. Alternatively, it may also include a first ferrule connector and a second ferrule connector. The two ends of the first ferrule connector are respectively sealed and connected to the side of the capillary tube that enters the ion vacuum pump and the ion vacuum pump, and the two ends of the second ferrule connector are respectively sealed and connected to the other side of the capillary tube that exits the getter pump and the getter pump.

[0011] Furthermore, it also includes a sample inlet tube and a sample inlet valve located on the side of the membrane sample inlet assembly away from the leak. The sample inlet valve, the membrane sample inlet assembly and the leak are connected in series via the sample inlet tube. One end of the leak is connected to the sample inlet tube, and the other end of the leak is connected to the capillary tube.

[0012] Furthermore, it also includes a leak valve installed on the leak hole.

[0013] Furthermore, it also includes an intermittent injection control module, which is electrically connected to the ion vacuum pump and is used to control the injection valve and the leak valve to open and close intermittently according to a preset cycle. At the same time, it dynamically adjusts the operating power of the ion vacuum pump according to the opening and closing status of the injection path.

[0014] A method for establishing vacuum in a small-volume, low-power mass spectrometer, applied to the aforementioned small-volume, low-power mass spectrometer vacuum system, includes the following steps: S1 Pre-vacuuming: Pre-vacuuming the vacuum chamber of the mass spectrometer until the vacuum level of the vacuum chamber reaches the start-up and operation conditions of the ion vacuum pump and getter pump. S2 Vacuum Establishment and Maintenance: The getter pump is started and activated to adsorb active gases in the vacuum chamber, activating the subsequent ion vacuum pump. After the ion vacuum pump is ignited, the power supply to the getter pump is disconnected. The ion vacuum pump captures residual inert gases in the vacuum chamber. The desorbed gases released during the activation of the getter pump and the ignition of the ion vacuum pump are removed using an external pre-evacuation pump group. Once the vacuum maintenance pump group is running stably and the vacuum degree of the vacuum chamber reaches the standard, the external pre-evacuation pump group is turned off, completing the establishment and long-term maintenance of the ultra-high vacuum environment in the vacuum chamber. At the same time, the operating current of the ion vacuum pump is collected in real time, and the real-time vacuum degree of the vacuum chamber is obtained based on the correspondence between current and vacuum degree. S3 High-Pressure Sample Introduction Detection: After the sample to be tested undergoes stepwise decompression and molecular sieving through the membrane sample introduction assembly and the leak, it is sent into the capillary for terminal decompression and finally sent to the ion source end of the mass spectrometer probe in the vacuum chamber through the capillary outlet.

[0015] Furthermore, in step S3, the opening and closing of the injection valve is controlled by an intermittent injection mode, and the operating power of the ion vacuum pump is dynamically adjusted according to the opening and closing status of the injection valve: when the injection valve is open, the operating power of the ion vacuum pump is increased to maintain a stable vacuum; when the injection valve is closed, the operating power of the ion vacuum pump is reduced to reduce the average power consumption of the system; when the injection valve is closed and the high-pressure injection detection is completed, the electrical control system enters a low-power operation mode to reduce the average power consumption of the electrical control system.

[0016] The small-volume, low-power mass spectrometer vacuum system and setup method of the present invention have the following advantages: 1. By combining an ion vacuum pump and a getter pump into a vacuum maintenance pump group, the targeted adsorption and capture of reactive gases and residual inert gases by both pumps achieve efficient establishment and stable maintenance of an ultra-high vacuum environment within the vacuum chamber. The getter pump only requires a short power supply during the activation phase and can efficiently adsorb reactive gases without continuous power supply during normal operation. The ion vacuum pump only needs to handle residual inert gases that the getter pump cannot capture, resulting in extremely low operating load. Compared to the traditional combination of mechanical pumps and turbomolecular pumps that require continuous high-power operation, this significantly reduces the core energy consumption of the vacuum maintenance process. At the same time, the vacuum level of the vacuum chamber is directly fed back from the operating current of the ion vacuum pump, eliminating the need for additional vacuum gauges and supporting detection components. This greatly simplifies the system structure, reduces the overall system size, and eliminates the continuous power consumption of vacuum gauges and supporting detection circuits, reducing the static operating energy consumption of the system. When sample injection and detection are not required, the operating mode of the electrical control system in the mass spectrometer vacuum system can be switched to a low-power operating mode to further reduce the overall system power consumption. By incorporating a capillary tube inserted into the vacuum maintenance pump assembly, along with a membrane sample introduction component and a leak-through multi-stage decompression sample introduction unit, step-by-step decompression and molecular screening of samples are achieved. This solves the problem of high-pressure sample introduction easily damaging the vacuum environment and core components, while also accurately delivering the sample to the ion source end of the mass spectrometer probe, reducing sample transmission loss and improving detection sensitivity. At the same time, the integrated design of the sample introduction unit and the vacuum maintenance pump assembly effectively compresses the overall system size and reduces hardware redundancy. From both structural and functional perspectives, it achieves the core design goals of a small size and low power consumption for the mass spectrometer vacuum system, adapting to the needs of portable and on-site mass spectrometry detection.

[0017] 2. A straight-through flange and a pre-vacuum unit integrated thereon are added. On the one hand, the straight-through flange serves as the connection between the vacuum maintenance pump unit and the vacuum chamber, ensuring the sealed connection of the pumping channel and providing a coaxial foundation for the capillary tube, ensuring the accuracy of the sample transfer path and avoiding sample loss caused by pipe bends. On the other hand, integrating the pre-vacuum unit onto the straight-through flange eliminates the need for an additional pre-vacuum interface in the vacuum chamber, reducing the number of processing points in the chamber and the risk of vacuum seal leakage, further improving the system's integration and vacuum sealing performance. At the same time, the pre-vacuum path, vacuum maintenance, and sample inlet flow channel form a compact integrated layout, effectively reducing the system's footprint and balancing the requirements of pre-vacuum function implementation and system miniaturization.

[0018] 3. By using the structural design of the angle valve and vacuum pre-evacuation interface, and coordinating the connection between the angle valve and the middle pipe side interface of the straight flange, the space occupied by the pre-evacuation unit is greatly reduced, achieving a small size and high integration of the system. This also reduces the risk of leakage in the ultra-high vacuum environment. At the same time, a through-flow pre-evacuation channel is formed, which greatly improves the pre-evacuation efficiency. It is compatible with the working mode of keeping the angle valve open during the activation phase of the getter pump, which can quickly discharge the activation desorption gas to ensure the performance and service life of the vacuum maintenance pump unit.

[0019] 4. The series connection between the getter pump, the straight-through flange, and the ion vacuum pump allows the gas in the vacuum chamber to flow through the getter pump first and then into the ion vacuum pump. This ensures that the vast majority of reactive gases are adsorbed by the getter pump, with only a very small amount of inert gas entering the ion vacuum pump. This significantly reduces the operating load of the ion vacuum pump, further reducing its power consumption and extending its service life. Furthermore, the getter pump, located between the straight-through flange and the ion vacuum pump, forms a physical barrier, effectively preventing titanium sputtering particles generated during the operation of the ion vacuum pump from entering the vacuum chamber. This avoids sputtering particles contaminating the ion source and other precision components of the mass spectrometer probe, ensuring the detection accuracy and long-term operational stability of the mass spectrometer.

[0020] 5. By integrating the capillary tube with the ion vacuum pump and getter pump in a coaxial manner, no additional sealing and isolation structure is required. The capillary tube itself can completely isolate the internal sample inlet channel from the vacuum pump channel, further simplifying system components and improving system integration. At the same time, it eliminates the risk of vacuum leakage and channel interconnection caused by the aging and failure of additional seals, significantly improving the long-term stability of the system. The integrated structure also ensures the coaxiality of the capillary tube, avoiding sample transmission loss caused by tube bending and offset, and effectively improving the detection sensitivity of the mass spectrometer. Alternatively, by installing a compression fitting at the end of the ion vacuum pump and getter pump for a sealed connection with the capillary tube, the coaxiality of the capillary tube can also be ensured, avoiding sample transmission loss caused by tube bending and offset, and effectively improving the detection sensitivity of the mass spectrometer.

[0021] 6. By connecting the membrane injection assembly and the leak in series via the injection tube into a single multi-stage decompression flow path, the continuity and sealing of the sample transport path are ensured, preventing leakage during decompression. Simultaneously, high-pressure samples can sequentially pass through the membrane injection assembly and the leak along a predetermined path to complete step-by-step decompression and molecular sieving, making the decompression process more stable and controllable. This effectively avoids pressure surges caused by high-pressure samples directly entering subsequent flow channels. Furthermore, the standardized series connection of the injection tubes makes the disassembly, assembly, and maintenance of each component of the multi-stage decompression injection unit more convenient. Different specifications of membrane injection assemblies and leaks can be flexibly replaced according to actual testing needs, improving the system's versatility and practicality. The direct connection between the leak and the capillary allows the sample, after multi-stage decompression, to smoothly enter the capillary for final decompression, ensuring the continuity of the decompression process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a small-volume, low-power mass spectrometer vacuum system according to the present invention. Detailed Implementation

[0023] To better understand the purpose, structure, and function of this invention, the following detailed description of the small-volume, low-power mass spectrometer vacuum system and its establishment method, in conjunction with the accompanying drawings, is provided.

[0024] like Figure 1 As shown, the present invention provides a small-volume, low-power mass spectrometer vacuum system, including a multi-stage depressurization sample introduction unit 1, a vacuum chamber 2, a vacuum maintenance pump group 3 sealed and connected to the vacuum chamber 2, and a quadrupole mass spectrometer probe 4 fixedly installed in the vacuum chamber 2. The vacuum maintenance pump group 3 adopts a composite pump structure that combines an ion vacuum pump 5 and a getter pump 6. The getter pump 6 permanently captures most of the active gases such as nitrogen, oxygen, and water vapor in the vacuum chamber 2 through the chemical adsorption of highly active metal materials inside. The ion vacuum pump 5, on the other hand, uses a strong magnetic field to confine electrons to ionize gas molecules and captures residual inert gases that the getter pump 6 cannot handle through physical embedding and chemical adsorption. The two complement each other and can quickly establish and maintain an ultra-high vacuum environment for a long time. At the same time, the operating current of the ion vacuum pump 5 has a stable linear relationship with the gas pressure in the vacuum chamber 2. By collecting its operating current, the real-time vacuum level of the vacuum chamber 2 can be directly obtained, eliminating the need for the vacuum gauge and matching detection circuit that must be configured separately in traditional solutions. This not only reduces the system size and hardware cost, but also reduces the number of vacuum sealing points and the risk of leakage.

[0025] The multi-stage depressurization sample introduction unit 1 includes a membrane sample introduction component 8 and a leak 9 arranged in series along the sample transport direction, and a capillary tube 10 coaxially inserted inside the entire vacuum maintenance pump group 3. The inlet of the capillary tube 10 is sealed and connected to the leak 9, and the outlet of the capillary tube 10 is connected to the vacuum chamber 2, with the outlet end precisely aligned with the ion source end of the mass spectrometer probe 4. This coaxial structure significantly shortens the sample transport distance from the leak 9 to the ion source end, reduces the adsorption loss of the sample on the inner wall of the tube, and effectively improves the detection sensitivity. At the same time, the sample introduction channel and the vacuum pumping unit are integrated in the same axial space, which greatly reduces the overall volume of the system. With the step-by-step depressurization and molecular screening of the membrane sample introduction component 8, the leak 9 and the capillary tube 10, the high-pressure sample can be smoothly converted into a low-pressure micro-flow of gas suitable for the vacuum environment, solving the problem that high-pressure sample introduction in traditional solutions easily damages the vacuum environment and core components.

[0026] Preferably, the system also includes a straight flange 11 and a pre-vacuum unit 12 integrally formed on the straight flange 11. One end of the straight flange 11 is sealed and connected to the vacuum maintaining pump group 3, and the other end is sealed and fixed to the opening of the vacuum chamber 2. The capillary tube 10 is coaxially inserted into the central through hole of the straight flange 11. The straight flange 11 serves as a sealing connection between the vacuum maintaining pump group 3 and the vacuum chamber 2, ensuring the coaxial connection and vacuum sealing of the pumping channel. On the other hand, it provides an integrated mounting point for the pre-vacuum unit 12, eliminating the need for additional pre-vacuum interfaces on the vacuum chamber 2, further reducing the number of machining points and the risk of sealing leakage. At the same time, the central through hole ensures the coaxiality of the capillary tube 10, avoiding sample transmission difficulties or increased losses caused by pipe bends, making the sample delivery path more accurate and smoother.

[0027] Furthermore, the pre-vacuum unit 12 includes an angle valve 13 and a vacuum pre-vacuum interface 18 fixed to the outer end of the angle valve 13. The straight flange 11 includes a pipe section disposed in the middle. The air inlet end of the angle valve 13 is sealed and connected to the side interface on the pipe section through a metal pipe 14, so that the pre-vacuum air path is connected to the internal flow channel of the straight flange 11 and the vacuum chamber 2. Since a large amount of desorption gas will be released during the activation process of the getter pump 6, after the pre-vacuum is completed and the vacuum degree of the vacuum chamber reaches the pump group start-up conditions, the angle valve and the external pre-vacuum pump group are kept open, and the getter pump 6 and the external pre-vacuum pump group are started in sequence. The sub-vacuum pump 5 can continuously and rapidly discharge the gas released by the activation of the getter pump 6 and the ignition of the ion vacuum pump 5 through an external pre-evacuation pump group. This avoids the desorbed gas from affecting the cavity vacuum level, causing poisoning of the getter active material, or excessive load on the ion vacuum pump. After the vacuum maintenance pump group is running stably and the cavity vacuum level reaches the ultra-high vacuum standard, the angle valve and the external pre-evacuation pump group are closed. The vacuum maintenance pump group then independently maintains the cavity vacuum environment for a long time. This not only ensures the stability of the pump group activation and start-up process, but also significantly extends the service life of the vacuum maintenance pump group and reduces equipment maintenance costs.

[0028] Furthermore, within the vacuum maintaining pump assembly 3, one end of the getter pump 6 is sealed and connected to the end face of the straight flange 11, and the other end of the getter pump 6 is sealed and connected to the titanium cathode type ion vacuum pump 5, forming a coaxial series layout of the straight flange 11, the getter pump 6, and the ion vacuum pump 5. With this structure, the gas in the vacuum chamber 2 first flows through the getter pump 6, where the active gas is directly adsorbed and captured. The remaining inert gas in the chamber enters the ion vacuum pump 5 at the rear, significantly reducing the operating load of the ion vacuum pump 5. This not only further reduces the operating power consumption of the ion vacuum pump 5 but also extends its service life. Simultaneously, the getter pump 6, located between the ion vacuum pump 5 and the vacuum chamber 2, forms a physical barrier, completely preventing titanium sputtering particles generated during the operation of the ion vacuum pump 5 from entering the vacuum chamber 2. This avoids titanium particle contamination of the ion source, detector, and other precision components of the mass spectrometer probe 4, ensuring detection accuracy and long-term operational stability of the equipment.

[0029] It should be noted that the capillary tube 10 is coaxially inserted into the axial through-hole of the vacuum maintenance pump assembly. The capillary tube 10 is integrally formed with one side of the ion vacuum pump 5 and with the other side of the getter pump 6. Through its own structure, the capillary tube 10 forms a complete isolation barrier within the vacuum maintenance pump assembly, creating an inlet channel for high-pressure sample transport within the capillary tube 10. This channel is independent of and does not communicate with the internal chambers of the vacuum maintenance pump assembly, ensuring effective sample transmission and preventing signal loss and sensitivity reduction. Simultaneously, the integrally formed structure eliminates the risk of sealing points and leakage associated with additional seals, significantly improving the long-term operational stability of the vacuum system. It also ensures the coaxiality of the capillary tube, preventing sample transport difficulties or increased losses due to pipe bending or misalignment, resulting in a more precise and smoother sample delivery path.

[0030] Those skilled in the art can also, according to actual conditions, set a first ferrule connector and a second ferrule connector with a through-end structure in the system. The two ends of the first ferrule connector are respectively sealed to one side of the capillary tube 10 entering the ion vacuum pump 5 and to the ion vacuum pump 5. The two ends of the second ferrule connector are respectively sealed to the other side of the capillary tube 10 exiting the getter pump 6 and to the getter pump 6. This can also achieve long-term stable operation of the vacuum system, ensure the coaxiality of the capillary tube 10, avoid sample transmission difficulties or increased losses caused by tube bending or offset, and make the sample delivery path more accurate and smoother.

[0031] This embodiment also includes a high-strength injection tube 16 and an injection valve 7 located on the side of the membrane injection assembly 8 away from the leak 9. The injection valve 7, the membrane injection assembly 8, and the leak 9 are connected in series in a sealed manner through the high-strength injection tube 16. One end of the injection tube 16 is a high-pressure injection end 15, the air inlet end of the leak 9 is sealed and connected to the other end of the injection tube 16, and the air outlet end of the leak 9 is sealed and connected to the capillary tube 10. The high-strength injection tube 16 has a pressure resistance value no less than the maximum inlet pressure of the high-pressure sample to be tested. It can withstand the continuous impact of the high-pressure sample without cracking or leakage. At the same time, the series structure forms a continuous step-by-step depressurization flow path: the injection valve 7 controls the opening and closing of the entire injection path, the membrane injection component 8 first performs primary depressurization and selective molecular screening on the high-pressure sample to achieve preliminary separation of impurity gases, the leak 9 performs secondary depressurization on the sample, and finally the capillary tube 10 completes the final fine depressurization. The whole process achieves stable depressurization of the high-pressure sample and avoids the situation where the high-pressure gas flow directly impacts the vacuum chamber 2. It is suitable for the direct injection requirements of high-pressure samples and does not require additional pre-depressurization equipment, further improving the system integration and the convenience of on-site testing.

[0032] Furthermore, the air inlet end of the leak hole 9 is also equipped with a leak valve 17. The control circuits of the leak valve 17 and the sample injection valve 7 are independent of each other, and the two can be opened and closed independently to control the opening and closing of the sample injection path. This independent circuit design enables flexible control of the sample injection valve 7 and the leak valve 17. The two valves can be opened and closed independently according to actual testing needs, adapting to diverse application scenarios such as equipment debugging, step-by-step sample injection, and emergency single valve shut-off. At the same time, the independent control circuit significantly reduces the risk of system failure. A failure in one control loop will not affect the normal opening and closing of the other valve, further improving the safety and reliability of equipment operation.

[0033] Furthermore, the mass spectrometer's vacuum system includes an electronic control system, which comprises an intermittent sample injection control module electrically connected to the ion vacuum pump 5. This module controls the intermittent opening and closing of the sample injection valve 7 and the leak valve 17 according to a preset cycle. It also dynamically adjusts the operating power of the ion vacuum pump 5 based on the opening and closing status of the sample injection path. In practical detection scenarios, mass spectrometry does not require continuous sample injection; detection can be completed simply by opening the sample injection path within the detection cycle. The intermittent opening and closing setting significantly reduces the total amount of gas entering the vacuum chamber 2, lowering the overall load on the vacuum maintenance pump group 3. Simultaneously, in conjunction with the dynamic power adjustment of the ion vacuum pump 5, when the sample injection valve 7 is open and the sample enters the chamber, the operating power of the ion vacuum pump 5 is increased to quickly offset vacuum fluctuations caused by the incoming gas, maintaining a stable chamber vacuum and ensuring detection accuracy. When the sample injection valve 7 is closed and no sample enters, the operating power of the ion vacuum pump 5 is reduced, only needing to maintain the basic vacuum level. This significantly reduces the system's average operating power consumption, making it particularly suitable for battery-powered scenarios with portable mass spectrometers and effectively extending the equipment's on-site operating time.

[0034] It is understood that in this embodiment, the getter pump 6 and the ion vacuum pump 5, the angle valve 13 and the pipeline 14, and the angle valve 13 and the vacuum pre-evacuation interface 18 are all connected by flange assemblies to enhance the sealing between adjacent structures.

[0035] Based on the aforementioned small-volume, low-power mass spectrometer vacuum system, this invention also provides a small-volume, low-power mass spectrometer vacuum establishment method, specifically including the following steps: S1 Pre-vacuum: Connect the pre-vacuum pump group to the vacuum pre-vacuum interface 18, open the angle valve 13 and start the pre-vacuum pump group to continuously pump air into the vacuum chamber 2 of the mass spectrometer until the vacuum degree of the vacuum chamber 2 reaches the starting and operating conditions of the ion vacuum pump 5 and the getter pump 6, so as to create the necessary medium-high vacuum environment for the normal operation of the core pump group. S2 Vacuum Establishment and Maintenance: After pre-vacuuming is completed, keep angle valve 13 and the external pre-vacuum pump group open. First, briefly power on the getter pump 6 to activate it. Later in the activation phase of getter pump 6, start the ion vacuum pump 5. After the ion vacuum pump 5 is ignited, disconnect the power supply to getter pump 6. Relying on the chemical adsorption of getter pump 6, it continuously adsorbs active gases in vacuum chamber 2 without continuous power supply. The ion vacuum pump 5 captures residual inert gases not adsorbed by getter pump 6. The external pre-vacuum pump group continuously removes the gases released during the activation of getter pump 6 and the ignition of ion vacuum pump 5. The desorbed gas is removed to prevent it from affecting the vacuum level of the cavity, causing poisoning of the getter active material, or overloading the ion vacuum pump. After the vacuum maintenance pump group 3 is running stably and the vacuum level of the vacuum cavity 2 reaches the ultra-high vacuum standard, the angle valve 13 and the external pre-evacuation pump group are closed. The vacuum maintenance pump group 3 independently completes the establishment and long-term maintenance of the ultra-high vacuum environment of the vacuum cavity 2. At the same time, during the operation of the ion vacuum pump 5, its operating current is collected in real time. Based on the pre-calibrated linear correspondence between current and vacuum level, the vacuum level data of the vacuum cavity 2 is obtained in real time without the need for additional vacuum detection components. S3 High-Pressure Sample Injection Detection: The high-pressure sample to be tested does not require additional pre-stage pressure reduction treatment. It is directly connected to the inlet end of the injection valve 7. After opening the injection valve 7 and the leak valve 17, the sample to be tested undergoes step-by-step pressure reduction and molecular screening through the membrane injection assembly 8 and the leak 9. It is then sent into the capillary 10 installed in the vacuum maintenance pump group 3 for final fine pressure reduction. Finally, it is smoothly sent into the vacuum chamber 2 through the outlet of the capillary 10 and accurately delivered to the ion source end of the mass spectrometer probe 4 to complete the ionization and detection of the sample.

[0036] Preferably, during the actual detection process in step S3, the opening and closing of the injection valve 7 can be controlled through an intermittent injection mode. Simultaneously, the operating power of the ion vacuum pump 5 is dynamically adjusted according to the opening and closing status of the injection valve 7: when the injection valve 7 is open and the sample enters the vacuum chamber 2, the operating power of the ion vacuum pump 5 is increased to quickly maintain a stable vacuum level and ensure the accuracy of the detection data; when the injection valve 7 is closed and no sample is injected, the operating power of the ion vacuum pump 5 is reduced to maintain only the basic vacuum level, further reducing the average operating power consumption of the system and meeting the requirements for portable and low-power use. When the injection valve is closed and high-pressure injection detection is completed, the electronic control system of the mass spectrometer vacuum system switches the operating mode to a low-power operating mode to reduce the average power consumption of the overall system.

[0037] It is particularly important to emphasize that in the S2 vacuum establishment and maintenance process described above, the getter pump only requires a short power supply during the activation phase. During normal operation, it can efficiently adsorb reactive gases without continuous power supply. The ion vacuum pump only needs to handle residual inert gases that the getter pump cannot capture, resulting in extremely low operating load. Compared to the traditional combination of mechanical pumps and turbomolecular pumps that require continuous high-power operation, this significantly reduces the core energy consumption of the vacuum maintenance process. The design of using the ion vacuum pump's operating current to feedback the vacuum level eliminates the need for a vacuum gauge, thus eliminating the static power consumption of additional detection components. Combined with the dynamic power adjustment of intermittent sample injection and the low-power operation mode, the system achieves low-power control throughout the entire process from vacuum establishment and maintenance to detection operation. This is suitable for battery-powered scenarios of portable mass spectrometers, significantly extending the on-site battery life of the equipment. This truly realizes the miniaturization, low power consumption, and on-site application of the mass spectrometer vacuum system.

[0038] The terms “above,” “below,” and “within” as used above include the number itself; the terms “exceeding” and “excluding” do not include the number itself.

[0039] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific descriptions herein should not be construed as limiting the substance and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention. The various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0040] If the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

Claims

1. A small-volume, low-power mass spectrometer vacuum system, characterized in that, The system includes a multi-stage depressurization sample introduction unit, a vacuum chamber, a vacuum maintenance pump assembly connected to the vacuum chamber, and a mass spectrometer probe housed within the vacuum chamber. The vacuum maintenance pump assembly includes an ion vacuum pump and a getter pump. The getter pump is used to adsorb reactive gases within the vacuum chamber, while the ion vacuum pump is used to capture residual inert gases within the vacuum chamber. The operating current of the ion vacuum pump is used to provide feedback on the vacuum level of the vacuum chamber. The multi-stage depressurization sample introduction unit includes a membrane sample introduction component, a leak, and a capillary tube inserted through the vacuum maintenance pump assembly, arranged in series along the sample transport direction. The inlet of the capillary tube is connected to the leak, and the outlet of the capillary tube is connected to the vacuum chamber. The capillary tube is positioned corresponding to the ion source end of the mass spectrometer probe and is used to progressively depressurize and molecularly screen the sample before it is introduced into the vacuum chamber.

2. The small-volume, low-power mass spectrometer vacuum system according to claim 1, characterized in that, It also includes a through flange and a pre-vacuum unit installed on the through flange. One end of the through flange is connected to the vacuum maintaining pump group, and the other end is connected to the vacuum chamber. The capillary tube passes through the through flange.

3. The small-volume, low-power mass spectrometer vacuum system according to claim 2, characterized in that, The pre-vacuum unit includes an angle valve and a vacuum pre-vacuum port located on one side of the angle valve. The straight flange includes a pipe section located in the middle, and the other side of the angle valve is connected to a side port on the pipe section.

4. The small-volume, low-power mass spectrometer vacuum system according to claim 2, characterized in that, One end of the getter pump is connected to a through flange, and the other end of the getter pump is connected to an ion vacuum pump.

5. The small-volume, low-power mass spectrometer vacuum system according to claim 1, characterized in that, A capillary tube is coaxially inserted through the axial through hole of the vacuum maintaining pump unit. The side of the capillary tube that enters the ion vacuum pump is integrally formed with the ion vacuum pump, and the other side of the capillary tube that exits the getter pump is integrally formed with the getter pump. Alternatively, it may also include a first ferrule connector and a second ferrule connector. The two ends of the first ferrule connector are respectively sealed to the side of the capillary tube that enters the ion vacuum pump and the ion vacuum pump, and the two ends of the second ferrule connector are respectively sealed to the other side of the capillary tube that exits the getter pump and the getter pump.

6. The small-volume, low-power mass spectrometer vacuum system according to any one of claims 1 to 4, characterized in that, It also includes a sample inlet tube and a sample inlet valve located on the side of the membrane sample inlet assembly away from the leak. The sample inlet valve, the membrane sample inlet assembly and the leak are connected in series via the sample inlet tube. One end of the leak is connected to the sample inlet tube and the other end of the leak is connected to the capillary tube.

7. The small-volume, low-power mass spectrometer vacuum system according to claim 6, characterized in that, It also includes a leak valve installed on the leak hole.

8. The small-volume, low-power mass spectrometer vacuum system according to claim 7, characterized in that, It also includes an intermittent injection control module, which is electrically connected to the ion vacuum pump and is used to control the injection valve and the leak valve to open and close intermittently according to a preset cycle. At the same time, it dynamically adjusts the operating power of the ion vacuum pump according to the opening and closing status of the injection path.

9. A method for establishing a vacuum in a small-volume, low-power mass spectrometer, characterized in that, Applied to the system as described in any one of claims 1 to 8, the method comprises the following steps: S1 Pre-vacuuming: Pre-vacuuming the vacuum chamber of the mass spectrometer until the vacuum level of the vacuum chamber reaches the start-up and operation conditions of the ion vacuum pump and getter pump. S2 Vacuum Establishment and Maintenance: The getter pump is started and activated to adsorb active gases in the vacuum chamber. The ion vacuum pump is then activated and started. After the ion vacuum pump is ignited, the power supply to the getter pump is disconnected. The ion vacuum pump captures residual inert gases in the vacuum chamber. The desorbed gases released during the activation of the getter pump and the ignition of the ion vacuum pump are removed using an external pre-evacuation pump group. Once the vacuum maintenance pump group is running stably and the vacuum degree of the vacuum chamber reaches the standard, the external pre-evacuation pump group is turned off, thus completing the establishment and long-term maintenance of the ultra-high vacuum environment in the vacuum chamber. The operating current of the ion vacuum pump is collected in real time, and the real-time vacuum degree of the vacuum chamber is obtained based on the correspondence between current and vacuum degree. S3 High-Pressure Sample Introduction Detection: After the sample to be tested passes through the membrane sample introduction component and the leak to complete the step-by-step decompression and molecular screening, it is sent into the capillary for terminal decompression, and finally sent to the ion source end of the mass spectrometer probe in the vacuum chamber through the capillary outlet.

10. The method for establishing a vacuum in a small-volume, low-power mass spectrometer according to claim 9, characterized in that, In step S3, the opening and closing of the injection valve is controlled by an intermittent injection mode, and the operating power of the ion vacuum pump is dynamically adjusted according to the opening and closing status of the injection valve: when the injection valve is open, the operating power of the ion vacuum pump is increased to maintain a stable vacuum; when the injection valve is closed, the operating power of the ion vacuum pump is reduced to reduce the average power consumption of the system; when the injection valve is closed and the high-pressure injection detection is completed, the electrical control system enters a low-power operation mode to reduce the average power consumption of the electrical control system.

Images