Method for monitoring and discriminating large particle airborne particles in clean rooms

Abstract

The application discloses a clean room large-particle suspended particulate monitoring and distinguishing method, which comprises the following steps: S1, collecting a gas sample; S2, counting large-particle particulates; S3, collecting large-particle particulates; S4, transferring the large-particle particulate sample; S5, distinguishing the composition of the large-particle particulates; and S6, locating the source of the large-particle particulates. The source of the large-particle particulates is mainly located through component classification and recognition and database atlas comparison. In the application, the number of large-particle particulates in a clean room caused by personnel activities and the like can be monitored in real time, and the exact source of the particulates can be given. The application solves the source and identification of large-particle particulates caused by accidental activities in a clean room. The method provides scientific data support for maintaining a clean room such as a spacecraft assembly and for researching methods for reducing large particles caused by accidental factors.

Description

Technical Field

[0001] This invention relates to the field of precision instruments and measurement technology, and in particular to a method for monitoring and identifying large-diameter suspended particulate matter in cleanrooms. Background Technology

[0002] When spacecraft are assembled and tested in cleanrooms, particles smaller than 10 μm are typically continuously monitored. However, in actual operation, due to factors such as personnel movement and the transfer of product tooling, fibrous particles larger than 10 μm may be suspended in the air. If purging or venting operations are performed on critical components such as propulsion system pipelines under these conditions, it could pose a risk to product quality. Currently, cleanrooms lack methods for monitoring large-diameter particulate matter suspension, making it impossible to accurately determine whether the operating environment meets requirements. Therefore, researching methods for detecting and identifying large-diameter particulate matter in cleanrooms is a key technological challenge. Summary of the Invention

[0003] The purpose of this invention is to provide a method for monitoring and identifying large-diameter suspended particulate matter in cleanrooms in order to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for monitoring and identifying large-diameter suspended particulate matter in cleanrooms includes the following steps:

[0006] S1. Gas sample collection; Gas sample collection is mainly achieved through the device's collection port, which can perform fixed-position collection and collection from the free end of the slit.

[0007] S2, Large-diameter particle counting; Large-diameter particle counting is mainly achieved by a large-diameter particle counter, which can record the number of particles within a specified diameter range in real time.

[0008] S3. Large particle size collection: Large particle size collection is mainly achieved by the collection device at the air outlet, which can collect large particle size during the test.

[0009] S4. Transfer of large-diameter particulate matter samples; The transfer of large-diameter particulate matter samples is mainly achieved by a transfer device in conjunction with standardized transfer actions, which can transfer and encapsulate large-diameter particulate matter without damage.

[0010] S5. Identification of large-diameter particulate matter composition; Identification of large-diameter particulate matter composition is mainly performed by professional laboratories using microscopic infrared testing, electron microscopy energy dispersive spectroscopy analysis, and microscopic morphology imaging.

[0011] S6. Location of large-diameter particulate matter sources; Location of large-diameter particulate matter sources is mainly achieved through component classification and identification, and database map comparison.

[0012] Preferably, the sampling port in step S1 can be adjusted according to different height requirements. The sampling port includes an isodynamic sampling head, a self-locking quick-connect tracheal adapter, and a metal hose. One end of the metal hose is connected to the isodynamic sampling head through the self-locking quick-connect tracheal adapter, and the other end is connected to the instrument's air inlet through the self-locking quick-connect tracheal adapter.

[0013] Preferably, in step S2, the large particle counter is a laser light scattering type laser particle counter. It uses the principle of laser light scattering to amplify, collect and count the laser signal scattered by the particles. The range of its core component, the laser sensor, is selected to be 10μm to 100μm, and the flow rate of its vacuum pump needs to be selected to be not less than 28.3L / min.

[0014] Preferably, the collection device in step S3 is installed at the air outlet of the large particle counter and is mainly used to collect large particles between 10μm and 100μm. The collection device includes a filter layer, a collection chamber and a collection dish. The collection chamber has a pagoda quick-connect air inlet and is connected to the air outlet of the counter through a dust-free tube. The collection dish is fixed to the collection chamber by clamps.

[0015] Preferably, the transfer device in step S4 includes a glass slide cover, which is made of potassium bromide. The glass slide cover is placed on the collection dish, and the complete sample can be removed after inverting the dish.

[0016] Preferably, in step S5, the main components of the sample are qualitatively identified by micro-infrared spectroscopy to preliminarily identify the type of fibrous particles, and elemental analysis and micro-morphological imaging are performed by electron microscopy energy dispersive spectroscopy and micro-morphological imaging to obtain sub-nanometer microscopic longitudinal imaging, cross-sectional morphological imaging and component energy dispersive spectroscopy information of the sample.

[0017] Preferably, the location of the source of large-diameter particulate matter in step S6 is mainly obtained by comparing observation data with a sample library. The comparison objects are derived from a known standard sample library and key related known particulate matter samples.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. This application provides a method for monitoring and identifying large-diameter particles in cleanrooms. This method can monitor the number of large-diameter particles in cleanrooms caused by personnel activities in real time, and simultaneously identify their exact sources. This application solves the problem of identifying the sources of large-diameter particles caused by accidental activities in cleanrooms. This method provides scientific data support for maintaining cleanrooms such as those used in spacecraft assembly, and for researching methods to reduce large particles caused by accidental factors. Attached Figure Description

[0020] Figure 1A flowchart illustrating the steps of a method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to an embodiment of the present invention is shown.

[0021] Figure 2 A schematic diagram of the acquisition port structure provided according to an embodiment of the present invention is shown;

[0022] Figure 3 A schematic diagram of the collection device structure provided according to an embodiment of the present invention is shown;

[0023] Figure 4 A schematic diagram of the transfer device structure provided according to an embodiment of the present invention is shown.

[0024] Legend:

[0025] 1. Isodynamic sampling head; 2. Self-locking quick-connect tubing adapter; 3. Metal hose; 4. Instrument air inlet; 5. Filter layer; 6. Collection chamber; 7. Collection dish; 8. Glass slide cover. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1-4 The present invention provides a technical solution:

[0028] A method for monitoring and identifying large-diameter suspended particulate matter in cleanrooms includes the following steps:

[0029] S1. Gas sample collection; Gas sample collection is mainly achieved through the device's collection port, which can perform fixed-position collection and collection from the free end of the slit.

[0030] S2, Large-diameter particle counting; Large-diameter particle counting is mainly achieved by a large-diameter particle counter, which can record the number of particles within a specified diameter range in real time.

[0031] S3. Large particle size collection: Large particle size collection is mainly achieved by the collection device at the air outlet, which can collect large particle size during the test.

[0032] S4. Transfer of large-diameter particulate matter samples; The transfer of large-diameter particulate matter samples is mainly achieved by a transfer device in conjunction with standardized transfer actions, which can transfer and encapsulate large-diameter particulate matter without damage.

[0033] S5. Identification of large-diameter particulate matter composition; Identification of large-diameter particulate matter composition is mainly performed by professional laboratories using microscopic infrared testing, electron microscopy energy dispersive spectroscopy analysis, and microscopic morphology imaging.

[0034] S6. Location of large-diameter particulate matter sources; Location of large-diameter particulate matter sources is mainly achieved through component classification and identification, and database map comparison.

[0035] Specifically, such as Figure 2 As shown, the sampling port in step S1 can be adjusted according to different height requirements to be as close as possible to the sensitive area. The sampling port includes an isodynamic sampling head 1, a self-locking quick-connect tracheal adapter 2, and a metal hose 3. One end of the metal hose 3 is connected to the isodynamic sampling head 1 through the self-locking quick-connect tracheal adapter 2, and the other end is connected to the instrument air inlet 4 through the self-locking quick-connect tracheal adapter 2.

[0036] Gas sample collection should avoid introducing additional particulate matter as much as possible. After the collection port is removed, the instrument inlet 4, metal hose 3, and isodynamic sampling head 1 should all be sealed; the isodynamic sampling head 1 ensures that the airflow velocity near the sampling head is the same as the airflow velocity near the sampling space. Its appearance is that of an upward-facing cup, with a collection port cover at the top and a self-locking quick-connect tubing adapter 2 at the bottom. The self-locking quick-connect tubing adapter 2 connects the self-locking head of the movable collection port to the self-locking head of the metal hose 3. The metal hose 3 is a rigid, flexible, and upright universal positioning tubing, with lengths of 1m and 2m depending on the cleanroom size and the height of sensitive areas. The instrument collection port is the inlet of the large-diameter particulate matter monitoring and counting instrument, and it also uses a self-locking head structure.

[0037] When using the powered sampling head 1, two modes can be adopted depending on the usage requirements and the size of the sensitive space. First, if there are no particularly sensitive areas in the cleanroom, the universal adjustable metal hose 3 can be unplugged, and the movable sampling port can be directly connected to the instrument's sampling port for particulate matter collection. Second, if the cleanroom has specific sensitive areas, and these areas are small, a metal hose of appropriate length 3 can be installed, bent, adjusted, and fixed to a suitable position before particulate matter collection.

[0038] In step S2, the large-diameter particle counter adopts a laser light scattering type laser particle counter. It utilizes the principle of laser light scattering to amplify, collect, and count the laser signal scattered by the particles. The key point is the selection of components for the laser scattering type particle monitoring instrument. To meet the needs of large-diameter particles suspended for a short time, the range of its core component, the laser sensor, is selected to be 10μm to 100μm. Due to the semi-suspended characteristics of large-diameter particles, the flow rate of its vacuum pump needs to be selected to be no less than 28.3L / min. This laser particle counter with high flow rate and large-diameter counting can complete the real-time counting function of particles with predetermined characteristics within a certain range.

[0039] Specifically, such as Figure 3 As shown, the collection device in step S3 is installed at the air outlet of the large particle counter. It is mainly used to collect large particles between 10μm and 100μm. The collection device includes a filter layer 5, a collection chamber 6 and a collection dish 7. The collection chamber 6 has a pagoda quick-connect air inlet and is connected to the air outlet of the counter through a dust-free tube. The collection dish 7 is fixed to the collection chamber 6 by clamps.

[0040] To reduce the adhesion of large-diameter particles to the inner wall of the collection device, the materials for filter layer 5, collection chamber 6, and collection dish 7 are all PTFE (a significant characteristic of this material is its non-stick surface: known solid materials cannot adhere to its surface; it is a solid material with the lowest surface energy and does not generate electrostatic adsorption). Filter layer 5, collection chamber 6, and collection dish 7 are connected together by threads. The upper filter layer 5 consists of a 5μm stainless steel filter membrane (since large-diameter particles in cleanrooms are occasional and few in number, a filter membrane layer with a diameter less than 10μm is required) and its clamping structure, mainly used to intercept particles larger than 10μm.

[0041] After the test, the large-diameter particles trapped in the collection chamber 6 and collection dish 7 will settle to the bottom of collection dish 7 due to gravity. A glass slide 8 is placed at the bottom of collection dish 7. After standing for 1 hour after the test, the large-diameter particle sample from this test can be collected in collection dish 7.

[0042] Specifically, such as Figure 4 As shown, the transfer device in step S4 includes a glass slide cover 8, which is made of potassium bromide. The glass slide cover 8 is placed on the collection dish 7, and the complete sample can be removed after inverting it.

[0043] The entire sample transfer process requires removing the collection device from the site and sealing the air inlet with a plug. In a Class 10,000 cleanroom, the collection dish 7 is placed vertically and allowed sufficient settling time. The airflow in the cleanroom is then shut off, the collection device is opened vertically, and the coverslip 8 is quickly placed on top, with the edges sealed with tape. After completing this series of operations, the sample is removed from the Class 10,000 cleanroom. This series of equipment and procedures completes the sample transfer process.

[0044] In step S5, the main components of the sample are qualitatively identified by micro-infrared spectroscopy to preliminarily identify the types of fibrous particles, such as the components of most organic materials like cotton, wool, rabbit hair, polyester, and flax. Elemental analysis and microscopic morphology imaging are performed by electron microscopy energy dispersive spectroscopy and microscopic morphology imaging. The detection equipment can be, for example, a Zeiss Gemini 300 electron microscope, for sub-nanometer microscopic longitudinal imaging, cross-sectional morphology imaging, and component energy dispersive spectroscopy information of the sample.

[0045] In step S6, the source location of large-diameter particulate matter is mainly obtained by comparing observation data with a sample library. The comparison objects are from known standard sample libraries and key related known particulate matter samples.

[0046] The samples submitted for testing should also include particulate samples from known sources, such as tool debris samples, threaded debris samples from key areas, fibers from cleanroom garments, cleaning fabric fibers, personnel clothing fibers, hair samples, and skin flakes samples—samples that may cause large particulate contamination. For example, during the monitoring and identification of large particulate matter in a spacecraft cleanroom, more than 80 relevant samples were collected. These samples were simultaneously subjected to electron microscopy and energy dispersive spectroscopy analysis and microscopic morphology imaging. The resulting microscopic images and energy dispersive spectroscopy information were then stored in a sample library.

[0047] In the process of locating the source of large-diameter particulate matter, the sample library category is first selected based on the results of microscopic infrared spectroscopy. Then, the microscopic imaging image of the sample to be tested is compared with the microscopic images in the sample library to obtain preliminary location results. Finally, the energy dispersive spectral information of the matched sample components is compared in detail to ultimately confirm and locate the source.

[0048] The main content of the cleanroom large-diameter suspended particulate matter monitoring and identification method in this application is aimed at short-term suspended large-diameter particulate matter caused by personnel activities, equipment installation, and other activities in spacecraft assembly cleanrooms (cleanliness level approximately ISO 8). The particle size of the target particles is between 10 μm and 100 μm. This application is used for counting the number of such particles, sample collection, component identification, and source location.

[0049] This application presents a method for monitoring and identifying large-diameter particles in cleanrooms. This method allows for real-time monitoring of the number of large-diameter particles caused by personnel activities in cleanrooms, and simultaneously identifies their precise sources. This application solves the problem of identifying the sources of large-diameter particles caused by accidental activities in cleanrooms. This method provides scientific data support for maintaining cleanrooms such as those used in spacecraft assembly, and for researching methods to reduce large particles caused by accidental factors.

[0050] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for monitoring and identifying large-diameter suspended particulate matter in cleanrooms, characterized in that, Includes the following steps: S1. Gas sample collection; Gas sample collection is mainly achieved through the device's collection port, performing fixed-position collection and collection from the free end of the slit. S2, Large-diameter particle counting; Large-diameter particle counting is mainly achieved by a large-diameter particle counter, which records the number of particles within a specified diameter range in real time. S3. Large-diameter particulate matter collection; Large-diameter particulate matter collection is mainly achieved by the collection device at the outlet of the large-diameter particulate matter counter, collecting large-diameter particulate matter during the test. S4. Transfer of large-diameter particulate matter samples; The transfer of large-diameter particulate matter samples is mainly achieved by a transfer device in conjunction with standardized transfer actions, which performs non-destructive transfer and packaging of large-diameter particulate matter. S5. Identification of large-diameter particulate matter composition; Identification of large-diameter particulate matter composition is mainly performed by professional laboratories using microscopic infrared testing, electron microscopy energy dispersive spectroscopy analysis, and microscopic morphology imaging. S6. Source location of large-diameter particulate matter; Source location of large-diameter particulate matter is mainly achieved through component classification and identification, and database spectrum comparison. The collection device in step S3 includes a filter layer (5), a collection chamber (6), and a collection dish (7). The filter layer (5), the collection chamber (6), and the collection dish (7) are connected together by threads. The collection chamber (6) has a pagoda quick-connect air inlet and is connected to the air outlet of the large particle counter through a dust-free tube. The collection dish (7) is fixed to the collection chamber (6) by clamps. The filter layer (5) located on the upper layer is used to intercept 10μm large particle size particles. The large particle size particles intercepted in the collection chamber (6) and the collection dish (7) are deposited to the bottom of the collection dish (7) due to gravity. A glass cover plate (8) is placed at the bottom of the collection dish (7). In step S4, the collection dish (7) is covered with a glass slide (8), and after being inverted, the complete sample is taken out. The glass slide (8) is made of potassium bromide.

2. The method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to claim 1, characterized in that, The sampling port in step S1 needs to be adjusted according to different heights. The sampling port includes an isodynamic sampling head (1), a self-locking quick-connect tracheal adapter (2), and a metal hose (3). One end of the metal hose (3) is connected to the isodynamic sampling head (1) through the self-locking quick-connect tracheal adapter (2), and the other end is connected to the instrument air inlet (4) through the self-locking quick-connect tracheal adapter (2).

3. The method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to claim 1, characterized in that, In step S2, the large particle counter is a laser light scattering type laser particle counter. It uses the principle of laser light scattering to amplify, collect and count the laser signal scattered by the particles. The range of its core component, the laser sensor, is selected to be 10μm to 100μm, and the flow rate of its vacuum pump is selected to be not less than 28.3L / min.

4. The method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to claim 3, characterized in that, The collection device in step S3 is installed at the air outlet of the large particle counter and is mainly used to collect large particles with a diameter between 10μm and 100μm.

5. The method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to claim 1, characterized in that, In step S5, the main components of the sample are qualitatively identified by micro-infrared spectroscopy to preliminarily identify the type of fibrous particles. Elemental analysis and micro-morphological imaging are performed by electron microscopy energy dispersive spectroscopy and microscopic morphological imaging to obtain sub-nanometer longitudinal imaging, cross-sectional morphological imaging, and component energy dispersive spectroscopy information of the sample.

6. The method for monitoring and identifying large-diameter suspended particulate matter in a cleanroom according to claim 1, characterized in that, In step S6, the location of the source of large-diameter particulate matter is mainly obtained by comparing observation data with a sample library. The comparison objects are from known standard sample libraries and key related known particulate matter samples.

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