CN115219112A - Molecular Pump and Mass Spectrometer Leak Detector - Google Patents

Abstract

The embodiments of the present specification provide a molecular pump and a mass spectrometer leak detector, which relate to the field of detection equipment. The molecular pump includes: a housing with a cavity and a device accommodating cavity, the cavity is located above the device accommodating cavity along the direction of gravity, the device accommodating cavity is used for accommodating the air pumping equipment, and the empty The side wall of the cavity is provided with a connection port and a gas inlet for connecting the mass spectrometry detection device. The mass spectrometer leak detector includes: a mass spectrometry detection device with an ion source, a magnetic field and an amplifier, and the above-mentioned molecular pump. The gas entering the molecular pump from the gas inlet does not pass through the pumping equipment, and most of the gas enters the mass spectrometer detection device through the connecting port, which reduces the loss of the target gas when passing through the molecular pump and improves the accuracy of the mass spectrometer leak detector.

Description

Molecular Pump and Mass Spectrometer Leak Detector

technical field

The invention relates to the field of detection equipment, in particular to a molecular pump and a mass spectrometer leak detector using the molecular pump.

Background technique

A mass spectrometer leak detector is a specialized leak detection instrument. By detecting whether the target gas exists in the ambient gas, it can be realized whether there is a leak in the detected object. Usually, helium can be used as the target gas, and a corresponding mass spectrometer leak detector can be used to detect the presence of helium in the ambient gas.

Specifically, during use, helium gas is sprayed on one side of the device to be tested, and the leak detector is pumped from the other side. If the device under test has a leak, helium gas will enter the leak detector through the leak. When the helium gas entering the leak detector passes through the molecular pump of the leak detector, due to the small relative molecular mass of the helium gas, a part of the helium gas entering the leak detector can overcome the impeller force and enter the helium mass spectrometer detection device under the action of the compression ratio. A portion of the helium may be expelled with the airflow. This results in a very small amount of helium entering the helium mass spectrometry detection device, which is difficult to detect accurately.

Mass spectrometry leak detectors may include mass spectrometry detection devices and molecular pumps.

SUMMARY OF THE INVENTION

In view of this, the purpose of this specification is to provide a molecular pump capable of improving detection accuracy and a mass spectrometer leak detector using the molecular pump.

In order to achieve the above purpose, the present specification provides a molecular pump, which includes a housing with a cavity and a device accommodating cavity. Along the direction of gravity, the cavity is located above the device accommodating cavity, and the equipment accommodating cavity is used for accommodating pumping gas. Equipment, the side wall of the cavity is provided with a connection port and a gas inlet for connecting the mass spectrometry detection device.

The present specification also provides a mass spectrometer leak detector, comprising the above molecular pump and a mass spectrometry detection device, wherein the mass spectrometry detection device is provided with a connection port connected to the molecular pump.

Compared with the prior art, the mass spectrometer leak detector provided by the embodiments of the present specification is provided with a gas inlet and a connection port connected to the mass spectrometry detection device on the cavity of the molecular pump, and the relative positions of the gas inlet and the connection port are close, so that the gas The gas entering the cavity at the entrance overcomes the action of gravity and the pumping equipment and enters the mass spectrometry detection device from the cavity, thereby increasing the target gas entering the mass spectrometry detection device and meeting the requirements of improving the detection accuracy of the leak detector.

Description of drawings

Figure 1 shows a schematic diagram of providing a molecular pump using one embodiment of the present specification.

FIG. 2 is a schematic diagram of a molecular pump and a mass spectrometry detection device provided by an embodiment of the present specification.

FIG. 3 is a schematic diagram of a cross-sectional gas inlet and a connection port of a molecular pump provided by an embodiment of the present specification.

FIG. 4 shows a schematic diagram of a cross-sectional gas inlet and a connection port of a molecular pump provided by an embodiment of the present specification.

FIG. 5 is a schematic diagram of a cross-sectional gas inlet and a connection port of a molecular pump provided by an embodiment of the present specification.

FIG. 6 shows a schematic diagram of a cross-sectional gas inlet and a connection port of a molecular pump provided by an embodiment of the present specification.

FIG. 7 shows a schematic diagram of a cross-sectional gas inlet and a connection port of a molecular pump provided by an embodiment of the present specification.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

See Figure 1. The embodiment of the present specification provides a molecular pump 100 . The molecular pump 100 may include: a housing 102 having a cavity 108 and a device accommodating cavity 104, along the direction of gravity, the cavity 108 is located above the device accommodating cavity 102, and the device accommodating cavity 104 is used for accommodating the pump Gas equipment, the side wall of the cavity 108 is provided with a connection port 101 and a gas inlet 106 for connecting the mass spectrometry detection device 200 .

In some embodiments, the housing 102 may be used to provide support for the overall structure of the molecular pump 100 . The interior of the housing 122 may be hollow as a whole, and a cavity 108 and a device accommodating cavity 104 are formed along the direction of gravity.

It will be appreciated that cavity 108 may be a spatial structure that is not physically occupied by solids. It can also be understood that the cavity 108 provides a through channel for gas circulation. The portion of the housing 102 surrounding the cavity 108 constitutes a side wall of the cavity 108 . The cavity 108 may be part of the interior space of the housing 102 . The cavity 108 is in communication with the device accommodating cavity 104 .

The gas inlet 106 is provided on the side wall of the cavity 108 . The gas inlet 106 can be used for the gas to be detected to flow into the molecular pump 100 . The connection port 101 is also provided on the side wall of the cavity 108 , and the connection port 101 can be used for connecting the molecular pump 100 to the mass spectrometry detection device 200 .

See Figure 3, Figure 4, and Figure 5. In some embodiments, the outer shape of the housing 102 may be a rectangular parallelepiped extending along the direction of gravity, or a cylinder. Specifically, when the outer shape of the casing 102 can be a rectangular parallelepiped extending along the direction of gravity, the gas inlet 106 and the connecting port 101 can be located on the opposite side walls of the casing 102, and can be located in adjacent casings The side wall of the body 102 may also be the same as the side wall of the casing 102 . See Figure 5 and Figure 6. Preferably, the gas inlet 106 and the connection port 101 are arranged on the same side wall of the casing. Along the direction of gravity, the connection port 101 is located above the gas inlet 106. Due to the small relative molecular mass of the target gas, the gas inlet 106 enters the cavity. After 108 , it will diffuse upward, and it is easier to enter the connection port 101 located above the gas inlet 106 .

See Figure 7. When the outer shape of the casing 102 can be a cylinder, the gas inlet 106 can have a first penetrating direction penetrating the casing 102 , the connecting port 101 can have a second penetrating direction penetrating the casing, The first penetration direction and the second penetration direction tend to be perpendicular to the direction of gravity, and the included angle between the first penetration direction and the second penetration direction ranges from 0 to 180 degrees.

Referring to FIG. 7 , the angle α shown in FIG. 7 may be the included angle. A third reference plane perpendicular to the direction of gravity is provided. The third reference plane is not a plane of the molecular pump 100 itself, but an ideal plane constructed with the direction of gravity as a reference. The 0 degree may be that the projection of the first penetration direction on the third reference plane completely overlaps the projection of the second penetration direction on the third reference plane, and the 180 degree may be the first penetration direction The projection on the third reference plane and the projection of the second penetration direction on the third reference plane do not overlap and are parallel. Preferably, the included angle between the first penetration direction and the second penetration direction may range from 0 to 90 degrees. When the included angle between the first penetration direction and the second penetration direction is less than or equal to 90 degrees, the distance between the gas inlet 106 and the connection port 101 is relative to the distance between the first penetration direction and the second penetration direction. The included angle ranges from 90 to 180 degrees and the distance is relatively close, which is convenient for the gas to enter the mass spectrometry detection device.

In some embodiments, a first reference plane perpendicular to the first penetration direction may be provided. The first reference plane is not a plane of the molecular pump 100 itself, but is constructed based on the first penetration direction. In an ideal plane, the first reference plane can be parallel to the direction of gravity. The projection of the gas inlet 106 on the first reference plane at least partially overlaps the projection of the connection port 124 on the first reference plane. The projection of the gas inlet 106 on the first reference plane may refer to the contour edge of the gas inlet 106 closest to the first reference plane, and the projection of the connection port 101 on the first reference plane may refer to the connection port 101 For the contour edge closest to the first reference plane, the at least partial overlap of the projections may be a relationship in which the projections of the gas inlet 106 and the connection port 101 are completely covered and identical, and some projections occupy the same position.

In some embodiments, the gas flowing through the gas inlet 106 may be a mixture of target gas and ambient gas. Specifically, for example, the device under test is in a certain environment containing ambient gas, and the target gas is sprayed on one side of the device under test, and the leak detection port of the leak detector can directly cover the welding seam on the other side, and the joint Wait for the suspected leak. When the device under test has a leak, the mass spectrometer leak detector can pump the ambient gas and the target gas leaked from the leak into the instrument together to form a mixed gas. The target gas is a gas with relatively small molecular mass and stable properties, which can be detected by a corresponding mass spectrometry detection device. Specifically, for example, helium or hydrogen. The ambient gas is the gas in the environment where the object to be inspected exists. Specifically, for example, air.

When the mixed gas flowing in from the gas inlet 106 moves from the cavity 108 to the connection port 101, the target gas with a smaller relative molecular mass can be located in an upward position along the direction of gravity, and the ambient gas with a larger relative molecular mass can be located in the direction of gravity. lower position. The air extraction device in the device accommodating cavity 104 can extract the gas in the cavity, and the target gas in the relatively upper position is less affected by the air extraction device, and it is easier to enter the connection port 101, and the ambient gas in the relatively lower position is affected by the air extraction. The influence of the gas equipment is great, and the molecular pump 100 can be pumped out by the gas pumping equipment.

In some embodiments, along the direction of gravity, the device accommodating cavity 104 is located below the cavity 108 , which facilitates the extraction of gas in the cavity 108 , which can maintain the cavity 108 in a rarefied state and prolong the service life of the device.

The device housing cavity 104 may be a spatial structure that is not physically occupied by solids. It can also be understood that the device accommodating cavity 104 provides an accommodating space for the air extraction device and provides a structure for installing the air extraction device. The portion of the housing 102 surrounding the device accommodating cavity 104 constitutes a side wall of the device accommodating cavity 104 . The device housing chamber 104 may serve as a part of the interior space of the molecular pump 100 . The device accommodating cavity 104 and the cavity 108 may communicate with each other.

Specifically, the air pumping device has a force applied to the gas in the molecular pump 100 to flow toward the first opening 118 , so that the gas in the molecular pump 100 can be discharged from the first opening 118 .

In some embodiments, the air extraction device may be a single drive device or a combined drive device. Specifically, the combined driving device may be combined by the first driving device 112 and the second driving device 116 . Preferably, the first driving device 112 is a turbo vacuum pump, and the second driving device 116 is a drag vacuum pump.

The first opening 118 is provided on the side wall of the device accommodating chamber 104 , and the first opening 118 can be used for gas discharge in the molecular pump 100 . Along the direction of gravity, the first opening 118 is located below the gas inlet 106 and the gas pumping device, which facilitates the molecular pump 10 to discharge ambient gas with a relatively large molecular mass, and can maintain the cavity in a rarefied state. , prolong the service life of the equipment.

The second opening 114 and the third opening 110 are provided on the side wall of the device accommodating chamber 104 , and the second opening 114 and the third opening 110 can be used for the gas to be detected to flow into the molecular pump 100 Inside. Along the direction of gravity, the second opening 114 and the third opening 110 are located between the gas inlet 106 and the first opening 118 . Specifically, the second opening 114 can be provided on the side wall of the device accommodating cavity 104 within the range of the second driving device 116 ; the third opening 110 can be provided on the side wall of the device accommodating cavity 104 , and the first driving device 112 In the range.

When the target gas passes through the molecular pump 100, a loss will occur due to the impeller and the obstruction of the airflow, and the shorter the distance of the target gas passing through the molecular pump 100, the smaller the loss. The third opening 110 and the second opening 114 may be respectively disposed at different positions on the side wall of the device accommodating cavity 104 to provide various precision detection options for the device under inspection.

Along the direction of gravity, the gas inlet 106 , the third opening 110 , the second opening 114 and the first opening 118 may be sequentially disposed on the side wall of the device accommodating cavity 104 , and may be arranged according to the mass spectrometry detection device 200 . No reaction Select the appropriate gas inlet. Specifically, the target gas entering the mass spectrometry detection device 200 will cause the mass spectrometry detection device 200 to heat up. In order to protect the mass spectrometry detection device 200, the first opening 118 can be selected as the air inlet. The second opening 114 can be switched to be the airflow inlet. If the mass spectrometry detection device 200 is unresponsive, the third opening 110 can be switched to the airflow inlet. If the mass spectrometry detection device 200 is still unresponsive, the gas inlet 106 can be switched to Airflow into the port.

The size and specific location of the first opening 118 , the second opening 114 , the third opening 110 and the gas inlet 106 can be determined by the compression ratio calculation. The compression ratio may refer to the ratio of the pressure of the two openings of the molecular pump, and is used to describe the pumping capacity of the molecular pump between the two openings.

In some embodiments, there may be a first compression ratio between the first opening 118 and the third opening 110 . There may be a second compression ratio between the first opening 118 and the second opening 114 . There may be a third compression ratio between the first opening 118 and the gas inlet 106 .

In some embodiments, the value range of the ratio between the first compression ratio and the second compression ratio may be between 1,000 and 1,000,000. Preferably, the value range of the ratio may be between 50,000 and 220,000. . The value range of the ratio between the first compression ratio and the third compression ratio may be between 100 and 10,000. Preferably, the value range of the ratio can be between 800 and 3600.

In some embodiments, the diameter of the gas inlet 106 may be greater than or equal to 25 mm, and the diameter of the connection port 101 may approach the diameter of the gas inlet 106 . Preferably, the ratio of the area of the connection port 101 to the area of the gas inlet 108 may range from 0.9 to 1.3, so that the gas flowing from the gas inlet 106 can enter the mass spectrometry detection device 200 through the connection port 101 .

In some embodiments, the gas inlet 106 , the connection port 101 , the first opening 118 , the second opening 114 and the third opening 110 may be through structures with circular cross-sections, which facilitates gas flow and improves the detection rate.

See Figure 2. The embodiments of this specification provide a mass spectrometry detection device 200 and a mass spectrometer leak detector of the molecular pump 100 . The mass spectrometry detection device 200 can detect the type of gas through mass spectrometry. The mass spectrometry detection device 200 may include a mass spectrometry chamber having an ion source 206 , a magnetic field 204 and an amplifier 202 . The ion source 206 may include a filament that emits electrons. The magnetic field 204 may have a controllable voltage. The amplifier 202 may include a receiving device for receiving target ions, a converting device for converting the received target ions into an electrical signal, and an amplifying device for amplifying the electrical signal. Electrons emitted from the filament in the ion source 206 collide with the incoming gas to ionize the gas into positive ions. After these positive ions enter the magnetic field 204, they are deflected by the Lorentz force to form arc-shaped orbits. By controlling the voltage across the magnetic field 204, the deflection orbit of the target gas ions is controlled, so that the target gas ions reach the amplifier 202 and be detected.

The connection port 101 may be provided on the shell 208 of the mass spectrometry detection apparatus, and the connection port 101 may be used for the mass spectrometry detection apparatus 200 to be connected to the molecular pump 100 .

In order to facilitate the gas entering the ion source 206 in the mass spectrometry detection device 200, a second reference plane perpendicular to the second penetration direction is provided, and the projection of the ion source 206 on the second reference plane is connected to the connection port The projection of 101 on the second reference plane at least partially overlaps, and the ion source 206 can be located between the connection port 101 and the magnetic field 204, so that the distance from the target gas from the connection port 101 to the ion source 206 can be shortened, Reduce the loss of target gas. The second reference plane is not a plane of the molecular pump 100 itself, but an ideal plane constructed with the second penetration direction as a reference and parallel to the direction of gravity. The projection of the ion source 206 on the second reference plane may refer to the contour edge of the ion source 206 closest to the second reference plane, and the projection of the connection port 124 on the second reference plane may refer to the connection port 124 For the contour edge closest to the second reference plane, the at least partial overlap of the projections may be a relationship in which the projections of the ion source 206 and the connection port 124 are completely covered and identical, and some projections occupy the same position.

In some embodiments, the mass spectrometer leak detector may be a helium mass spectrometer leak detector or a hydrogen mass spectrometer leak detector. Specifically, when the target gas is helium and the mass spectrometry detection device is a helium mass spectrometry detection device, the mass spectrometer leak detector is a helium mass spectrometer leak detector; when the target gas is hydrogen and the mass spectrometry detection device is a hydrogen mass spectrometry detection device, the The mass spectrometer leak detector is a hydrogen mass spectrometer leak detector.

The technical features of the above embodiments can be combined arbitrarily. In order to simplify the description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, all It is considered to be the range described in this specification.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. within.

Claims (10)

1. A molecular pump, characterized by comprising: the mass spectrometry detection device comprises a shell with a cavity and an equipment accommodating cavity, wherein the cavity is located above the equipment accommodating cavity along the gravity direction, the equipment accommodating cavity is used for accommodating air pumping equipment, and a connecting port and a gas inlet which are used for connecting the mass spectrometry detection device are arranged on the side wall of the cavity.

2. The molecular pump of claim 1, wherein the device receiving chamber side wall has a first opening, the pumping device applying a force to the gas entering from the gas inlet that flows toward the first opening.

3. The molecular pump of claim 1, wherein the device-receiving chamber sidewall is provided with a second opening and a third opening along a direction of gravity, the gas inlet is located above the second opening and the third opening, and the second opening is located between the first opening and the third opening; a first compression ratio is arranged between the first opening and the third opening, a second compression ratio is arranged between the first opening and the second opening, and the value range of the ratio of the first compression ratio to the second compression ratio is between 1000 and 1000000.

4. The molecular pump of claim 3, wherein a third compression ratio is provided between the first opening and the gas inlet, and a ratio between the first compression ratio and the third compression ratio ranges from 100 to 10000.

5. The molecular pump of claim 1, wherein the gas inlet has a diameter greater than or equal to 25mm, and the connection port has a diameter approaching the diameter of the gas inlet.

6. The molecular pump of claim 1, wherein a ratio of an area of the connection port to an area of the gas inlet is in a range of 0.9 to 1.3.

7. The molecular pump of claim 1, wherein the gas inlet has a first penetrating direction that penetrates the housing, the connection port has a second penetrating direction that penetrates the housing, and an included angle between the first penetrating direction and the second penetrating direction ranges from 0 to 90 degrees.

8. The molecular pump of claim 7, wherein a first reference plane is provided perpendicular to the first direction of penetration, and a projection of the gas inlet port on the first reference plane at least partially overlaps a projection of the connection port on the first reference plane.

9. A mass spectrometer leak detector, comprising: a mass spectrometry detection apparatus having an ion source, a magnetic field and an amplifier, and a molecular pump according to any one of claims 1 to 8.

10. The mass spectrometry detection device of claim 9, wherein the mass spectrometry detection device is in communication with the molecular pump via the connection port to provide a second reference plane perpendicular to the second direction of penetration, wherein a projection of the ion source onto the second reference plane at least partially overlaps a projection of the connection port onto the second reference plane, and wherein the ion source is positioned between the connection port and the magnetic field.

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