Vacuum pumping system for mass spectrometer

Abstract

The present invention discloses a vacuum pumping system suitable for a mass spectrometer, comprising a first air pumping unit and a second air pumping unit, wherein the first air pumping unit comprises a molecular pump and a mechanical pump which are connected and arranged, and the air pumping port of the molecular pump is connected to the vacuum chamber of the mass spectrometer; the second air pumping unit comprises a vacuum air path, an air inlet valve and a pre-pumping valve, one end of the vacuum air path is connected to the transition chamber of the mass spectrometer, and the other end of the vacuum air path is divided into two paths, the first path is connected to the outside atmosphere through the air inlet valve, and the second path is connected to the vacuum chamber through the pre-pumping valve. The present invention realizes the connection between the vacuum chamber and the transition chamber by using the pre-pumping valve, and when vacuuming, the molecular pump can indirectly extract the vacuum from the transition chamber through the vacuum chamber, thereby realizing the rapid pre-pumping of the transition chamber, greatly shortening the sample injection waiting time, and improving the detection efficiency.

Description

Technical Field

[0001] The present invention relates to a mass spectrometer, and in particular to a vacuum pumping system suitable for the mass spectrometer. Background Art

[0002] Matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS, hereinafter referred to as mass spectrometer) needs to perform sample analysis under vacuum, that is, the sample is placed in the vacuum chamber of the mass spectrometer for sample dissociation. Figure 1 As shown, currently, most of the vacuum chamber 2.1 (enclosed by the box body 2.4 and the cover plate 2.3) is evacuated by a molecular pump to ensure the vacuum degree of the vacuum chamber; meanwhile, in order to protect the molecular pump 1.1, a fore-stage mechanical pump is also provided at the front end of the molecular pump.

[0003] The vacuum chamber 2.1 of the mass spectrometer is relatively large, and the vacuum chamber takes a long time to evacuate. If the sample is taken in and out by repeatedly replenishing air and evacuating the vacuum chamber, the detection efficiency of the mass spectrometer is seriously reduced. For this reason, most existing mass spectrometers have a transition chamber 2.2 (a take-in and take-out opening is provided on the cover plate 2.3 of the vacuum chamber, and the transition chamber is surrounded by a sample target groove F against the bottom of the take-in and take-out opening and a sealing cover M covering the take-in and take-out opening), as shown in detail. Figure 1 During operation, the sample can be taken and placed by evacuating and pre-evacuating the transition chamber, thereby improving the detection efficiency.

[0004] The existing pre-pumping method of the transition chamber is to use the mechanical pump of the mass spectrometer. When the vacuum degree of the transition chamber reaches the preset vacuum degree, the sample target groove descends to a preset height, and the transition chamber and the vacuum chamber are connected to form a whole, thereby achieving stable sampling. However, due to the relatively long pre-pumping time of the mechanical pump, the sample waiting time is long, which cannot meet the rapid detection requirements of high-throughput samples.

[0005] Therefore, a high-power mechanical pump is usually used to shorten the pre-pumping time of the transition chamber. The greater the power of the mechanical pump, the larger its volume and the more expensive its price. Therefore, a high-power mechanical pump is often accompanied by a larger mass spectrometer and a higher cost. Therefore, how to design a vacuum pumping system that can achieve rapid pre-pumping of the transition chamber is an important technical problem that needs to be solved in this industry. Summary of the invention

[0006] The object of the present invention is to provide a vacuum pumping system suitable for a mass spectrometer, in which a transition chamber and a vacuum chamber of the vacuum pumping system are connected via a pre-pumping valve, and the transition chamber can be pre-pumped via the vacuum chamber, thereby achieving rapid pre-pumping of the transition chamber and shortening the waiting time for sample injection.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The vacuum pumping system suitable for a mass spectrometer described in the present invention includes a first vacuum unit and a second vacuum unit, the first vacuum unit includes a molecular pump and a mechanical pump which are connected to each other, and the vacuum port of the molecular pump is connected to the vacuum chamber of the mass spectrometer; the second vacuum unit includes a vacuum air path, an air inlet valve and a pre-vacuum valve, one end of the vacuum air path is connected to the transition chamber of the mass spectrometer, and the other end of the vacuum air path is divided into two paths, the first path is connected to the outside atmosphere through the air inlet valve, and the second path is connected to the vacuum chamber through the pre-vacuum valve.

[0009] In a preferred embodiment of the present invention, the vacuum pumping system further comprises a vacuum detection component for detecting the vacuum degree of the transition chamber, and the vacuum detection component is arranged in the vacuum air path between the pre-evacuation valve and the transition chamber. More preferably, the vacuum detection component is a vacuum gauge.

[0010] In a preferred embodiment of the present invention, the vacuum pumping system further comprises a valve body manifold disposed on an outer wall of the vacuum chamber, and the air inlet valve and the pre-evacuation valve are mounted on the valve body manifold.

[0011] In a preferred embodiment of the present invention, the vacuum air path includes a first connecting hole and a second connecting hole vertically opened on the valve body block, and a first connecting channel and a second connecting channel horizontally arranged on the valve body block, one end of the first connecting channel is connected to the transition chamber and the other end thereof is connected to the first connecting hole; one end of the second connecting channel is connected to the vacuum chamber and the other end thereof is connected to the second connecting hole;

[0012] The vacuum air path also includes a first channel and a second channel horizontally opened on the valve body block, one end of the first channel is connected to the first connecting hole and the other end is connected to the first interface of the intake valve, one end of the second channel is connected to the second interface of the intake valve and the other end is connected to the outside atmosphere;

[0013] The vacuum air circuit also includes a third channel and a fourth channel horizontally opened on the valve body block, one end of the third channel is connected to the first connecting hole and the other end is connected to the first interface of the pre-pumping valve, one end of the fourth channel is connected to the second interface of the pre-pumping valve and the other end is connected to the second connecting hole.

[0014] In another preferred embodiment of the present invention, the vacuum air circuit also includes a vacuum detection channel vertically opened on the valve body block, one end of the vacuum detection channel is connected to the first connecting hole and the other end thereof has a countersunk hole, and the detection part of the vacuum detection component is inserted into the countersunk hole.

[0015] In another preferred embodiment of the present invention, a silencer (with built-in filter) is provided at one end of the second channel connected to the outside atmosphere.

[0016] In another preferred embodiment of the present invention, the vacuum system further includes a buffer chamber and a buffer valve, the first interface of the buffer chamber is connected to the suction port of the mechanical pump, and the second interface of the buffer chamber is connected to the transition chamber through the buffer valve.

[0017] In a preferred embodiment of the present invention, the upper or lower portion of one side of the valve body block protrudes outward to form a mounting table, and the mounting table is sealed on the outer wall of the vacuum chamber, effectively reducing the contact area between the side of the valve body block and the outer wall.

[0018] In another preferred embodiment of the present invention, the vacuum system also includes a negative pressure buffer unit, which includes a buffer chamber and a buffer valve, wherein a first interface of the buffer chamber is connected to an air suction port of the mechanical pump, and a second interface of the buffer chamber is connected to the transition chamber through the buffer valve.

[0019] In another preferred embodiment of the present invention, the vacuum system further includes a negative pressure buffer unit, and the negative pressure buffer unit further includes a buffer chamber and a buffer valve, the first interface of the buffer chamber is connected to the vacuum chamber through the pre-vacuum valve, and the second interface of the buffer chamber is connected to the transition chamber through the buffer valve.

[0020] The present invention realizes the connection between the vacuum chamber and the transition chamber by using a pre-pumping valve. When evacuating the vacuum, the molecular pump can indirectly draw vacuum to the transition chamber through the vacuum chamber, thereby realizing rapid pre-pumping of the transition chamber, greatly shortening the sample injection waiting time and improving the detection efficiency.

[0021] The valve manifold of the present invention is sealed and installed on the cover plate of the vacuum chamber, and the pre-pumping valve, vacuum gauge and air inlet valve can be integrated and installed on the valve manifold, reducing the gas path structure, making the mass spectrometer neater, and effectively reducing the failure caused by pulling the gas path or gas path friction. At the same time, the vacuum gauge can detect the vacuum degree of the transition chamber to ensure that the pre-pumping vacuum degree of the transition chamber is within the preset range when each sample is tested. When the vacuum degree of the transition chamber is difficult to be pre-pumped within the preset range, the control system of the mass spectrometer issues an error prompt.

[0022] The vacuum system of the present invention also includes a buffer chamber, through which the transition chamber can be pre-pumped first, and then the vacuum chamber can be used to pre-pump the transition chamber, or the negative pressure of the buffer chamber can be used to quickly pre-pump the transition chamber in one step. The buffer chamber can cache the negative pressure and can achieve a rapid drop in the transition chamber, thereby shortening the pre-pumping time of the transition chamber and improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of an existing mass spectrometer (mechanical pump is omitted).

[0024] Figure 2 1 is a diagram showing the installation status of the first embodiment of the present invention on a mass spectrometer.

[0025] Figure 3 This is a diagram showing the installation status of the intake valve and pre-pumping valve described in the present invention on the valve body block.

[0026] Figure 4 yes Figure 3 Front view of the middle valve body manifold.

[0027] Figure 5 yes Figure 4 DD section structure schematic diagram.

[0028] Figure 6 yes Figure 3 Right side view of the middle valve body manifold.

[0029] Figure 7 yes Figure 3 Left side view of the middle valve body manifold.

[0030] Figure 8 yes Figure 7 BB section structure schematic diagram.

[0031] Fig. 9 yes Figure 7 Schematic diagram of the CC cross-sectional structure.

[0032] Fig.10 yes Figure 3 Bottom view of the middle valve body manifold.

[0033] Fig.11 This is a vacuum air circuit diagram of the second implementation mode.

[0034] Fig.12 This is a vacuum air extraction circuit diagram of implementation mode three. DETAILED DESCRIPTION

[0035] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0036] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0037] It should also be noted that in the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0038] Implementation Method 1

[0039] like Figure 1-3 As shown, the vacuum pumping system suitable for the mass spectrometer described in this embodiment includes a first pumping unit and a second pumping unit. The first pumping unit includes a molecular pump 1.1 and a mechanical pump 1.2 (working pressure is 10 -2 Pa), the suction port of the molecular pump 1.1 is connected to the vacuum chamber 2.1 of the mass spectrometer; before detection (i.e., using the mass spectrometer to detect the sample), the molecular pump 1.1 is pre-pumped with the mechanical pump 1.2, and then the molecular pump 1.1 is started, and the molecular pump 1.1 is used to draw negative pressure to the vacuum chamber 2.1 (the mechanical pump 1.2 works continuously), so that the negative pressure of the vacuum chamber 2.1 maintains the high vacuum degree required by the sample (about 10 -6 mbar);

[0040] The second air extraction unit comprises a vacuum air path, an air inlet valve 3 and a pre-extraction valve 4. One end of the vacuum air path is connected to the transition chamber 2.2 of the mass spectrometer (surrounded by a sealing cover M and a sample target groove F in the vacuum chamber), and the other end of the vacuum air path is divided into two paths. The first path is connected to the outside atmosphere through the air inlet valve 3, and the second path is connected to the vacuum chamber 2.1 through the pre-extraction valve 4.

[0041] When taking and placing the sample, the sample target groove F of the vacuum chamber 2.1 is moved to the bottom of the access port of the vacuum chamber 2.1 and then lifted upward and pressed against the bottom edge of the access port. The sample target groove F and the sealing cover M at the access port form a transition chamber 2.2. At this time, the air inlet valve 3 replenishes air into the transition chamber 2.2. When the pressure in the transition chamber 2.2 is consistent with the external pressure, the sealing cover M at the access port is opened, and the sample is placed in the limit groove of the sample target groove F.

[0042] Then, cover the sealing cover M, close the air inlet valve 3 and open the pre-pumping valve 4 (to avoid the transition chamber and the vacuum before being connected, which causes the vacuum degree to transition instantly, and then causes the molecular pump to stop working due to the impact, the opening method of the pre-pumping valve 4 can be high-frequency opening and closing or small flow opening), so that the transition chamber 2.2 and the vacuum chamber 2.1 are in an intermittent connection state, and the molecular pump 1.1 can directly draw negative pressure to the transition chamber 2.2 through the vacuum chamber 2.1. Compared with the traditional method of using the mechanical pump 1.2 to draw negative pressure from the transition chamber 2.2, the present invention greatly shortens the pre-pumping time of the transition chamber 2.2 (can be controlled within 3s), further shortens the waiting time for the injection of each sample, improves the detection efficiency, and effectively meets the needs of high-throughput samples.

[0043] like Figure 2-3 As shown, the vacuum pumping system of this embodiment also includes a vacuum detection component (preferably a vacuum gauge 5, the signal output end of the vacuum gauge 5 is connected to the control system of the mass spectrometer). The vacuum gauge 5 is arranged on the vacuum air path between the pre-pumping valve 4 and the transition chamber 2.2, and can detect the vacuum degree of the transition chamber 2.2. The vacuum gauge 5 can transmit the detected vacuum degree to the control system. When the vacuum gauge 5 detects that the vacuum degree in the transition chamber 2.2 cannot reach the preset vacuum degree during the pre-pumping process, the control system will give an error prompt to ensure the normal sampling of each sample, thereby realizing accurate detection of the sample.

[0044] like Figure 2 As shown, the vacuum pumping system of this embodiment further includes a valve body manifold 6 arranged outside the vacuum chamber 2.1, and the air intake valve 3, the pre-pumping valve 4 (the air intake valve 3 and the pre-pumping valve 4 are preferably two-position two-way solenoid valves) and the vacuum gauge 5 can be integrated and installed on the valve body manifold 6, so that the entire structure can realize ventilation and rapid pre-pumping of the transition chamber 2.2 without external pipelines, making the overall structure of the mass spectrometer more concise. Specifically:

[0045] like Figure 7 As shown, the upper part of the rear side of the valve body manifold 6 has a mounting table protruding backwards, and the upper part of the valve body manifold 6 is horizontally provided with a pair of mounting holes 6.1 along the front-back direction. The bolts penetrated in each mounting hole 6.1 fix the valve body manifold 6 on the cover plate 2.3 of the vacuum chamber 2.1 (and ensure that the mounting table is sealed and attached to the cover plate 2.3), thereby reducing the contact area between the valve body manifold 6 and the vacuum chamber 2.1;

[0046] The cover plate 2.3 is provided with a first through hole communicating with the transition chamber 2.2 and a second through hole communicating with the vacuum chamber 2.1. The first through hole is communicated with a first connecting channel 6.4 described later, and the second through hole is communicated with a second connecting channel 6.5 described later, so that the valve body block 6 is connected with the vacuum chamber 2.1 and the transition chamber 2.2.

[0047] like Figure 3-5As shown, the vacuum air circuit includes a first connecting hole 6.2 and a second connecting hole 6.3 vertically opened on the valve body block 6, and a first connecting channel 6.4 and a second connecting channel 6.5 horizontally arranged on the valve body block 6. The first connecting hole 6.2 and the second connecting hole 6.3 are process holes vertically opened downward from the top surface of the valve body block 6. The upper parts of the first connecting hole 6.2 and the second connecting hole 6.3 are sealed with plugging parts (i.e. plugging heads) to prevent air leakage from the first connecting hole 6.2 and the second connecting hole 6.3; the first connecting channel 6.4 is connected to the transition chamber 2.2 through the first through hole and the other end thereof is connected to the first connecting hole 6.2, thereby realizing the connection between the first connecting hole 6.2 and the transition chamber 2.2; one end of the second connecting channel 6.5 is connected to the vacuum chamber 2.1 through the second through hole and the other end thereof is connected to the second connecting hole 6.3, thereby realizing the connection between the second connecting hole 6.3 and the vacuum chamber 2.1;

[0048] like Figure 7-9 As shown, the air intake valve 3 is fixedly mounted on the left side of the valve body block 6 by screws; the vacuum air path also includes a first channel 6.6 (a blind hole) and a second channel 6.7 (the second channel 6.7 is a through hole) opened horizontally to the right from the left side of the valve body block 6, the right end of the first channel 6.6 is connected to the first connecting hole 6.2 and the left end thereof is connected to the first interface of the air intake valve 3, the left end of the second channel 6.7 is connected to the second interface of the air intake valve 3 and the right end is equipped with a muffler H (with a built-in filter) connected to the outside atmosphere, and the outside air enters the transition chamber 2.2 successively through the second channel 6.7→intake valve 3→first channel 6.6→first connecting hole 6.2→first connecting channel 6.4→first through hole, so as to realize the air supply of the transition chamber 2.2, so as to facilitate opening the sealing cover M to place the sample; the muffler H can reduce the whistling sound caused by the excessively fast air intake speed;

[0049] like Figure 6 and Figure 8-9 As shown, the pre-pumping valve 4 is fixedly installed on the right side of the valve body block 6 by screws; the vacuum air path also includes a third channel 6.8 and a fourth channel 6.9 (the third channel 6.8 and the fourth channel 6.9 are both blind holes) opened horizontally to the left from the right side of the valve body block 6. The left end of the third channel 6.8 is connected to the first connection hole 6.2 and the right end is connected to the first interface of the pre-pumping valve 4. The right end of the fourth channel 6.9 is connected to the second interface of the pre-pumping valve 4 and its left end is connected to the second connection hole 6.3. The specific communication path is: transition chamber 2.2→first through hole→first connecting channel 6.4→first connecting hole 6.2→third channel 6.8→pre-pumping valve 4→fourth channel 6.9→second connection hole 6.3→second through hole→vacuum chamber 2.1, realizing the connection between the pre-pumping valve 4 and the vacuum chamber 2.1 and the transition chamber 2.2.

[0050] During actual installation, both the pre-pumping valve 4 and the air intake valve 3 adopt two-position two-way solenoid valves, and the control system of the mass spectrometer is used to control the automatic opening and closing of the pre-pumping valve 4 and the air intake valve 3, so as to realize automatic pre-pumping and air intake of the transition chamber 2.2, thereby meeting the requirements of taking and placing samples; at the same time, the opening mode of the pre-pumping valve 4 can be a small flow opening mode or a multi-frequency opening and closing mode, which can not only control the pre-pumping time of the transition chamber 2.2, but also prevent the molecular pump from stopping due to a sudden drop in the vacuum degree of the vacuum chamber, thereby improving the operation stability.

[0051] like Figure 8 and Fig.10 As shown, the vacuum air circuit also has a vacuum detection channel 6.10 vertically opened from the bottom surface of the valve body block 6. The upper end of the vacuum detection channel 6.10 is connected to the first connecting hole 6.2 and the lower end thereof has a countersunk hole 6.11. The detection part of the vacuum detection component is inserted in the countersunk hole 6.11 to detect the vacuum degree of the first connecting hole 6.2. Since the transition chamber 2.2 is connected to the first connecting hole 6.2 through the first through hole and the first connecting channel 6.4, the vacuum degree of the first connecting hole 6.2 is the same as the vacuum degree in the transition chamber 2.2. The vacuum degree in the transition chamber 2.2 can be monitored by monitoring the vacuum degree of the first connecting hole 6.2.

[0052] The working process of the vacuum system described in this embodiment is as follows:

[0053] Before testing, the mass spectrometer is started first, and the mechanical pump 1.2 pre-pumps the molecular pump 1.1, and then the molecular pump 1.1 is used to draw negative pressure to the vacuum chamber 2.1 (the mechanical pump 1.2 works continuously), so that the negative pressure of the vacuum chamber 2.1 reaches the high vacuum degree required for sample testing (about 10 -6 mbar);

[0054] When taking or placing a sample, the sample target groove F of the vacuum chamber 2.1 moves to the bottom of the taking or placing port, then rises upward and rests against the bottom edge of the taking or placing port. The sealing cover M provided at the taking or placing port and the sample target groove F form a transition chamber 2.2. The air intake valve 3 is opened, and the outside air enters the transition chamber 2.2 successively through the second channel 6.7 → air intake valve 3 → first channel 6.6 → first connecting hole 6.2 → first connecting channel 6.4 → first through hole, so that the pressure in the transition chamber 2.2 is restored to normal pressure, so that the sealing cover M can be opened to place a new sample to be tested. When the sample is placed, the sealing cover M is covered, and the pre-pumping valve 4 is opened (high frequency opening and closing or small flow opening) to pre-pump the transition chamber 2.2. The negative pressure path is as follows: vacuum chamber 2.1 → second through hole → second connecting hole 6.3 → fourth channel 6.9→pre-pumping valve 4→third channel 6.8→first connecting hole 6.2→first connecting channel 6.4→transition chamber 2.2, so that the vacuum chamber 2.1 and the transition chamber 2.2 are in a connected state, the high vacuum degree of the vacuum chamber 2.1 enables the transition chamber 2.2 to quickly reach the preset vacuum degree, and the vacuum chamber 2.1 and the molecular pump 1.1 are in a connected state, which is equivalent to the molecular pump 1.1 drawing vacuum from the transition chamber 2.2 through the vacuum chamber 2.1, realizing the rapid pre-pumping of the transition chamber 2.2, shortening the waiting time of the sample, and improving the detection efficiency; when the vacuum degree of the transition chamber 2.2 reaches the preset vacuum degree, the sample target slot F is moved to the ion source of the vacuum chamber 2.1 for sample dissociation detection; repeating this operation can realize the dissociation detection of multiple samples.

[0055] Implementation Method 2

[0056] The vacuum system described in this embodiment is different from the embodiment 1 in that the vacuum system further includes a negative pressure buffer unit. Fig.11 As shown, the negative pressure buffer unit includes a buffer chamber 7.1 and a buffer valve 7.2. The first interface of the buffer chamber 7.1 is connected to the suction port of the mechanical pump 1.2 through a first pipeline. The second interface of the buffer chamber 7.1 is connected to the transition chamber 2.2 through a second pipeline. The other end of the second pipeline is sealed and inserted into the connecting port on the sealing cover M plate at the corresponding position of the transition chamber 2.2. The buffer valve 7.2 (preferably a two-position two-way electric valve) is connected and arranged on the second pipeline.

[0057] During actual installation, the buffer valve 7.2 can also be integrated and installed on the valve body block 6. It is only necessary to open a fifth channel connected to the first connecting hole 6.2 on the front side of the valve body block 6. The buffer valve 7.2 is installed on the front side of the valve body block 6 and ensure that one interface of the buffer valve 7.2 is connected to the fifth channel and the other interface is connected to the second pipeline to ensure that when the buffer valve 7.2 is opened, the cache chamber 7.1 is in a connected state with the fifth channel through the buffer valve 7.2.

[0058] The working process of the vacuum system described in this embodiment is as follows:

[0059] Before the sample is tested, the mass spectrometer is started, and the mechanical pump 1.2 of the mass spectrometer pre-pumps the molecular pump 1.1, and then the molecular pump 1.1 is started, and the molecular pump 1.1 is used to draw negative pressure to the vacuum chamber 2.1 (the mechanical pump 1.2 works continuously), so that the negative pressure of the vacuum chamber 2.1 reaches the high vacuum degree required for sample testing (about 10 -6 mbar); during this process, the buffer valve 7.2 is in a closed state, and the mechanical pump 1.2 can simultaneously draw negative pressure from the outlet of the molecular pump 1.1 and the buffer chamber 7.1, so that the buffer chamber 7.1 is in a constant negative pressure state;

[0060] When taking or placing a sample, the sample target groove F of the vacuum chamber 2.1 moves to the bottom of the taking or placing port, then rises upward and rests against the bottom edge of the taking or placing port. The sealing cover M provided at the taking or placing port and the sample target groove F form a transition chamber 2.2. The air inlet valve 3 is opened, and the outside air enters the transition chamber 2.2 successively through the second channel 6.7→the air inlet valve 3→the first channel 6.6→the first connecting hole 6.2→the first connecting channel 6.4→the first through hole, so that the pressure in the transition chamber 2.2 is restored to normal pressure, so that the sealing cover M can be opened to place a new sample to be tested. After the sample is placed in the sample target groove F, the sealing cover M is covered to form a transition chamber 2.2. The buffer valve 7.2 is opened first, and the buffer chamber 7.1 is used to pre-pump the transition chamber 2.2. The negative pressure extraction path is: buffer chamber 7.1←buffer valve 7.2←fifth channel← The first connecting hole 6.2←first connecting channel 6.4←transition chamber 2.2, the transition chamber 2.2 and the buffer chamber 7.1 are in a connected state, the transition chamber 2.2 quickly reaches equilibrium under the negative pressure of the buffer chamber 7.1, and the pre-pumping of the transition chamber 2.2 is realized; then the buffer valve 7.2 is closed, the pre-pumping valve 4 is opened (high frequency opening and closing or small flow opening), and the high vacuum of the vacuum chamber 2.1 is used to continue to draw vacuum to the buffer chamber, so that the vacuum degree of the transition chamber 2.2 drops rapidly, and when the vacuum degree detected by the vacuum gauge 5 reaches the sampling condition, the pre-pumping valve 4 is closed, and the sample target slot F in the vacuum chamber 2.1 is moved downward to a preset height, the transition chamber 2.2 and the vacuum chamber 2.1 form a whole, and then the sample target slot F is moved to the bottom of the ion source for sample dissociation detection.

[0061] Implementation Method 3

[0062] The vacuum system described in this embodiment is different from that in the second embodiment in that the negative pressure buffer unit is different. Fig.12 As shown, the negative pressure buffer unit includes a buffer chamber 7.1 and a buffer valve 7.2 (the buffer valve 7.2 is preferably a two-position two-way solenoid valve), the first interface of the buffer chamber 7.1 is connected to the vacuum chamber 2.1 through the pre-evacuation valve 4, and the second interface of the buffer chamber 7.1 is connected to the transition chamber 2.2 through the buffer valve 7.2;

[0063] One interface of the pre-evacuation valve 4 is connected to the fourth channel 6.9, so that it is in communication with the vacuum chamber 2.1 through the fourth channel 6.9, the second connecting hole 6.3, and the second connecting channel 6.5; another interface of the pre-evacuation valve 4 is connected to the buffer chamber 7.1 through a connecting pipe, and another interface of the buffer chamber 7.1 is connected to the third channel 6.8 through a connecting pipe;

[0064] The buffer valve 7.2 is installed on the connecting pipe between the buffer chamber 7.1 and the pre-pumping valve 4, and can also be integrated on the valve body block 6, that is, the third channel 6.8 is opened on the front side of the valve body block 6 in the horizontal direction, and the buffer valve 7.2 is integrated on the front side of the valve body block 6 and ensures that one interface of the buffer valve 7.2 is connected to the valve body block 6 and the other interface is connected to the buffer chamber 7.1 through the connecting pipe. In this embodiment, the negative pressure extraction path of the transition chamber 2.2 is: vacuum chamber 2.1←second connecting channel 6.5←second connecting hole 6.3←fourth channel 6.9←pre-pumping valve 4←buffer chamber 7.1←third channel 6.8←first connecting hole 6.2←first connecting channel 6.4←transition chamber 2.2.

[0065] In actual work, the buffer valve 7.2 can be opened with a small flow or opened and closed at multiple frequencies to effectively control the vacuum balance time of the transition chamber 2.2 and the buffer chamber 7.1, thereby reducing the probability of vibration. At the same time, in order to further avoid the buffer valve 7.2 from whistling due to rapid flow, a muffler can be provided at one end of the buffer valve 7.2 connected to the transition chamber 2.2.

[0066] The specific working process of this implementation method is as follows:

[0067] Before the sample is tested, the mechanical pump 1.2 is first started for pre-pumping for a certain period of time, and then the molecular pump 1.1 is started to use the molecular pump 1.1 to draw negative pressure to the vacuum chamber 2.1 (the mechanical pump 1.2 works continuously), so that the pressure in the vacuum chamber 2.1 reaches the high vacuum degree required for sample testing (about 10 -6 mbar); during the vacuuming process, the pre-pumping valve 4 can be opened (opened at high frequency or at a small flow rate), the air inlet valve 3 and the buffer valve 7.2 can be closed, so that the vacuum chamber 2.1 and the buffer chamber 7.1 are in a connected state, and the molecular pump 1.1 is used to draw negative pressure to the buffer chamber 7.1, so that the vacuum degree in the buffer chamber 7.1 is close to that of the vacuum chamber 2.1, laying a foundation for realizing the rapid pre-pumping of the vacuum degree of the transition chamber 2.2;

[0068] When it is necessary to take or place a sample during the detection process, the sample target groove F of the vacuum chamber 2.1 moves to the bottom of the access port and then rises upward and rests against the bottom edge of the access port. The sealing cover M provided at the access port and the sample target groove F form a transition chamber 2.2. The air inlet valve 3 is opened, and the outside air enters the transition chamber 2.2 through the second channel 6.7 → the air inlet valve 3 → the first channel 6.6 → the first connecting hole 6.2 → the first connecting channel 6.4 → the first through hole, so that the pressure in the transition chamber 2.2 is restored to normal pressure, so that the sealing cover M can be opened to place a new sample to be tested.

[0069] After the sample is placed in the sample target slot F, the sealing cover M is put on to form a transition chamber 2.2, the pre-pumping valve 4 and the air inlet valve 3 are closed, and the buffer valve 7.2 is opened to connect the transition chamber 2.2 and the cache chamber 7.1. Since the vacuum degree in the cache chamber 7.1 is close to that in the vacuum chamber 2.1, the transition chamber 2.2 rapidly descends under the action of the cache chamber 7.1 to meet the sampling requirement, and then the buffer valve 7.2 is closed, and the sample target slot F in the vacuum chamber 2.1 is moved downward to a preset height, so that the transition chamber 2.2 and the vacuum chamber 2.1 form a whole, and then the sample target slot F is moved to the bottom of the ion source for sample dissociation detection.

[0070] It should be emphasized that the above embodiments are only specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications, replacements and improvements within the technical scope of the present invention, and these modifications and improvements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A vacuum pumping system suitable for a mass spectrometer, characterized in that: It includes a first air pumping unit and a second air pumping unit, the first air pumping unit includes a molecular pump and a mechanical pump which are connected to each other, and the air pumping port of the molecular pump is connected to the vacuum chamber of the mass spectrometer; the second air pumping unit includes a vacuum air path, an air inlet valve and a pre-pumping valve, one end of the vacuum air path is connected to the transition chamber of the mass spectrometer, and the other end of the vacuum air path is divided into two paths, the first path is connected to the outside atmosphere through the air inlet valve, and the second path is connected to the vacuum chamber through the pre-pumping valve.

2. The vacuum pumping system for mass spectrometer according to claim 1, characterized in that: The vacuum pumping system further comprises a vacuum detection component for detecting the vacuum degree of the transition chamber, wherein the vacuum detection component is arranged on the vacuum air path between the pre-vacuum valve and the transition chamber.

3. The vacuum pumping system for mass spectrometer according to claim 2, characterized in that: The vacuum detection component is a vacuum gauge.

4. The vacuum pumping system suitable for a mass spectrometer according to claim 2, characterized in that: The vacuum pumping system further comprises a valve body block arranged on the outer wall of the vacuum chamber, and the air inlet valve and the pre-pumping valve are mounted on the valve body block.

5. The vacuum pumping system for mass spectrometer according to claim 4, characterized in that: The vacuum air path includes a first connecting hole and a second connecting hole vertically opened on the valve body block, and a first connecting channel and a second connecting channel horizontally arranged on the valve body block, one end of the first connecting channel is connected to the transition chamber and the other end thereof is connected to the first connecting hole; one end of the second connecting channel is connected to the vacuum chamber and the other end thereof is connected to the second connecting hole; The vacuum air path also includes a first channel and a second channel horizontally opened on the valve body block, one end of the first channel is connected to the first connecting hole and the other end is connected to the first interface of the intake valve, one end of the second channel is connected to the second interface of the intake valve and the other end is connected to the outside atmosphere; The vacuum air circuit also includes a third channel and a fourth channel horizontally opened on the valve body block, one end of the third channel is connected to the first connecting hole and the other end is connected to the first interface of the pre-pumping valve, one end of the fourth channel is connected to the second interface of the pre-pumping valve and the other end is connected to the second connecting hole.

6. The vacuum pumping system suitable for a mass spectrometer according to claim 5, characterized in that: The vacuum air circuit also includes a vacuum detection channel vertically opened on the valve body block, one end of the vacuum detection channel is connected to the first connecting hole and the other end thereof has a countersunk hole, and the detection part of the vacuum detection component is inserted in the countersunk hole.

7. The vacuum pumping system for mass spectrometer according to claim 5, characterized in that: A silencer is provided at one end of the second channel communicating with the outside atmosphere.

8. The vacuum pumping system for mass spectrometer according to claim 4, characterized in that: The upper part or the lower part of one side surface of the valve body block protrudes outward to form a mounting table, and the mounting table is sealed and arranged on the outer wall of the vacuum chamber.

9. The vacuum pumping system suitable for a mass spectrometer according to claim 1 or 2, characterized in that: The vacuum system also includes a negative pressure buffer unit, which includes a buffer chamber and a buffer valve. The first interface of the buffer chamber is connected to the air suction port of the mechanical pump, and the second interface of the buffer chamber is connected to the transition chamber through the buffer valve.

10. The vacuum pumping system suitable for a mass spectrometer according to claim 1 or 2, characterized in that: The vacuum pumping system also includes a negative pressure buffer unit, which also includes a buffer chamber and a buffer valve. The first interface of the buffer chamber is connected to the vacuum chamber through the pre-evacuation valve, and the second interface of the buffer chamber is connected to the transition chamber through the buffer valve.

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