A clean bench with active dust reduction function and an active dust reduction method thereof

Abstract

The application discloses a clean workbench with active dust falling function and an active dust falling method thereof, and belongs to the technical field of clean workbenches.The clean workbench comprises a cabinet body, an operation table, a high-efficiency air filter and a fan, and is characterized in that: a negative pressure balance control device is arranged below the clean operation area, the negative pressure balance control device is a three-layer honeycomb opening structure, and comprises an upper working surface, a middle layer provided with a plurality of pressure sensors, and a bottom layer composed of a plurality of valves; an air outlet of the bottom layer is in communication with a return air area; the upper working surface is an operation platform for carrying objects, and uniformly distributed air holes are arranged on the operation platform; a valve corresponding to the position of each air hole is arranged on the bottom layer; and the valve is opened or closed by receiving an induction signal of the pressure sensor. Through the negative pressure balance control device with the honeycomb opening structure, the application realizes directional constraint of the source of pollutants, avoids diffusion, guarantees that the overall cleanliness meets the standard, improves the effective operation space of the clean workbench, and reduces the operation energy consumption.

Description

Technical Field

[0001] This invention relates to a cleanroom device, and more particularly to a cleanroom workbench with active dust reduction function and its active dust reduction method. Background Technology

[0002] Clean benches are widely used in modern precision manufacturing, biopharmaceuticals, microelectronics, medical devices, and laboratory research, where high levels of cleanliness are required in the operating environment. According to current standards (such as ISO 14644-1 and GB 50073), the air cleanliness of the clean bench operating area typically needs to reach ISO Class 5 or higher to ensure that products are assembled, tested, or processed in a low-dust, low-particulate environment.

[0003] To achieve this cleanliness level, existing technologies typically employ top- or side-mounted high-efficiency particulate air (HEPA / ULPA) filters to create a vertical or horizontal unidirectional airflow pattern within the operating area. Clean air is continuously supplied to the operating area and exhausted via a lower return or exhaust system. (See Appendix) Figure 1 As shown. This method can maintain the cleanliness requirements of the overall operating area to a certain extent.

[0004] However, in actual use, especially during workpiece processing, a large amount of dust pollution is generated. Once these pollutants detach from the workpiece surface, they are carried away by the airflow in the operating area and diffuse in all directions, causing the following problems:

[0005] 1. Severe local contamination makes it difficult to maintain cleanliness.

[0006] Contaminants accumulate continuously within the operating area 16, especially in the downstream area 17 of the workpiece (i.e., the downstream direction of the airflow), where the contaminant concentration is significantly higher than in other locations, causing this area to deviate from the designed cleanliness level for a long period of time.

[0007] 2. It affects work efficiency and product quality.

[0008] To avoid cross-contamination, operators have to frequently interrupt their work to clean or adjust the workstation layout, which reduces work efficiency and increases the risk of introducing secondary contamination.

[0009] 3. Low space utilization.

[0010] To prevent the spread of contamination, existing equipment often requires a large "safe clean distance" around the workpiece, which compresses the effective operating space of the clean bench and restricts the process layout per unit area.

[0011] 4. Increased energy consumption and operating costs.

[0012] To dilute and remove localized high concentrations of pollutants, the system typically needs to maintain a higher air exchange rate and a larger air volume, which increases the load on fans and filters, significantly increasing energy consumption and equipment operating costs.

[0013] In summary, while existing clean benches can meet Class 5 and above cleanliness requirements on a macro level, they lack targeted control measures for contamination sources, making it impossible to simultaneously meet the comprehensive needs of high cleanliness, high efficiency, low energy consumption, and high space utilization. Summary of the Invention

[0014] The purpose of this invention is to provide a clean workbench with active dust suppression function and its active dust suppression method. By improving the equipment and dust suppression method, a controllable dust suppression airflow structure can be actively formed near the workpiece in the clean operating area. This structure can directionally constrain and guide pollutants at their source, reducing their diffusion to the surrounding environment, thereby improving the overall utilization efficiency of the clean area and reducing operating energy consumption.

[0015] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a clean workbench with active dust reduction function, comprising a cabinet, a work surface, a high-efficiency air filter and a fan, wherein the outlet of the high-efficiency air filter blows clean air into the work surface to form a clean operating area, and the area below the work surface is a return air area, wherein the fan is located in the return air area, and a negative pressure balance control device is provided below the clean operating area, which has a three-layer honeycomb perforated structure, including an upper working surface with perforations, a middle layer with a plurality of pressure sensors, and a bottom layer composed of a plurality of valves, wherein the outlet of the bottom layer is connected to the return air area;

[0016] The upper working surface is an operating platform for carrying items, and a plurality of ventilation holes that connect to the middle layer below are evenly distributed on it.

[0017] The pressure sensors are arranged in an array around the vents on the intermediate layer according to the distribution of the vents above. The pressure sensors receive the sensing signals transmitted by the upper working surface.

[0018] A valve is provided on the bottom layer according to the position of the vent hole. The valve opens or closes upon receiving the sensing signal from the pressure sensor.

[0019] In the above technical solution, each of the valves includes an actuator and several blades. After receiving the sensing signal from the pressure sensor and performing comparison calculations, the controller selects the valve actuator at the corresponding position to drive the blades to move, thereby opening the negative pressure air intake channel from the vent on the upper working surface to the air outlet at the bottom.

[0020] In the above technical solution, the blade is connected to the actuator via a rotating shaft, and the actuator is composed of an electromagnet, a solenoid valve, or a motor.

[0021] In the above technical solution, the negative pressure balance control device includes a shell, and the upper working surface, middle layer and bottom layer are stacked sequentially inside the shell. A first negative pressure chamber is provided under the operating table. The operating table is connected to the cabinet through a detachable structure. When the negative pressure balance control device is used, the negative pressure balance control device replaces the operating table. The negative pressure balance control device is located in the first negative pressure chamber. The object to be measured is placed on the upper working surface. The bottom air outlet is connected to the inlet of the return air zone.

[0022] Its active dust reduction method is as follows: A negative pressure balance control device is installed below the clean operating area. When an object is placed on the upper working surface, the pressure sensor in the middle layer receives gravity sensing and transmits the sensing signal to the valve controller at the bottom layer. The controller determines the specific location of the sensing signal through a comparator and drives the valve actuator at the corresponding location to open the blades, so that the ventilation hole at the object placement location is connected to the return air area below, forming a local negative pressure suction channel to quickly absorb the pollutant airflow emitted by the object; in areas where no object is placed, the valve is closed and the airflow is normal.

[0023] In the above technical solution, the pressure sensors are distributed in a matrix, each corresponding to a position number. The valve is assigned an execution number for each pressure sensor position number. The controller stores an initial pressure value for each position number. When the measured pressure value exceeds the initial pressure value, it is determined that the position number is where the object is placed, and the corresponding execution number valve is driven to open the blade.

[0024] In the above technical solution, several blades are arranged in a ring and connected to the actuator via a rotating shaft. The controller drives the actuator to rotate the rotating shaft and controls the opening degree of the valve by setting the rotation angle.

[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] 1. In this invention, the position of the placed items is automatically detected by a pressure sensor, and the valve is opened only in the area of ​​the items to form a local negative pressure suction channel. The pollutants are drawn into the return air area (exhausted through the shortest path) the moment they are generated, avoiding diffusion to the surrounding area and downstream. This ensures that the entire area meets the Class 5 (Class 100) cleanliness requirements and solves the problem of excessive local pollution in traditional equipment.

[0027] 2. No need to reserve a safe distance between items for pollution prevention, the effective operating space can be increased by more than 30%, and it supports a higher density of workstation layout.

[0028] 3. When no items are placed in the area, the valves close, the return air resistance is controllable, and the system can adaptively adjust the fan speed according to the number of open valves, without having to maintain full high air volume operation, which can reduce operating energy consumption by 20%-35%.

[0029] 4. The work surface is connected by a detachable structure, and the upper work surface can directly replace the original work surface. Users can choose the work surface according to the experimental requirements, making it more flexible to use. There is no need to modify the main structure of the clean workbench, the modification cost is low, and it is compatible with various mainstream clean workbenches such as vertical and horizontal laminar flow. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of contaminant diffusion in a clean operating area according to the prior art of this invention;

[0031] Figure 2 This is a schematic diagram of the discharge of contaminants during operation of the horizontal laminar flow clean bench in Embodiment 1 of the present invention;

[0032] Figure 3 This is a schematic diagram of the three-layer honeycomb opening structure of the negative pressure balance control device in Embodiment 1 of the present invention;

[0033] Figure 4 yes Figure 3 Diagram showing the location of the trapdoor containing the item and its open status;

[0034] Figure 5 This is a schematic diagram showing the closed and open states of a single valve;

[0035] Figure 6 This is a diagram showing the arrangement of measuring points in Embodiment 1 of the present invention.

[0036] The components include: 1. Cabinet; 2. Work surface; 3. High-efficiency air filter; 4. Fan; 5. Negative pressure balance control device; 6. Upper work surface; 7. Middle layer; 8. Door; 9. Vent; 10. Pressure sensor; 11. Shaft; 12. Blades; 13. Clean operating area; 14. Return air area; 15. Air outlet; 16. Operating area; 17. Downstream area. Detailed Implementation

[0037] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Furthermore, the terms "vertical," "horizontal," "top," "bottom," "front," "back," "upper," "lower," "inner," and "outer," etc., mentioned in the embodiments of the present invention, indicate orientation or positional relationships based on the appendix. Figure 2The orientations or positional relationships shown, or the orientations or positional relationships in which the product is usually placed during use, are only for the purpose of facilitating the description of the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. The following will refer to the appendix... Figure 2-6 The present invention will be described in detail with reference to the embodiments.

[0038] Example 1: See Figures 2-6 As shown, a clean workbench with active dust reduction function includes a cabinet 1, a work surface 2, a high-efficiency air filter 3, and a fan 4. The air outlet of the high-efficiency air filter 3 blows clean air into the work surface 2, forming a clean operating area 13. Below the work surface 2 is a return air area 14. The fan 4 is located in the return air area 14. Below the clean operating area 13 is a negative pressure balance control device 5, which has a three-layer honeycomb perforated structure, including an upper working surface 6 with perforations, a middle layer 7, and a bottom layer composed of a plurality of valves 8. The air outlet 15 of the bottom layer is connected to the return air area 14.

[0039] The upper working surface 6 is an operating platform for carrying items, and a plurality of ventilation holes 9 are evenly distributed on it, which are connected to the middle layer below.

[0040] Based on the distribution of the vent holes 9 above, pressure sensors 10 are arranged in an array around the vent holes 9 on the intermediate layer. The pressure sensors 10 receive the sensing signals transmitted by the upper working surface 6.

[0041] A valve 8 is provided on the bottom layer according to the position of the vent 9. The valve 8 opens or closes upon receiving the sensing signal from the pressure sensor 10.

[0042] In this embodiment, taking a horizontal laminar flow clean bench as an example, the working area dimensions are 820 (width) × 600 (height) × 480 (depth) mm, the air outlet dimensions are 820 (width) × 600 (height) mm, and the cleanliness level is designed to be Class 5.

[0043] like Figure 3 As shown, the upper working surface 6 is a stainless steel tabletop fully covered with Φ5mm vent holes 9, spaced 40mm x 40mm apart. The middle layer 7 is an array of pressure sensors 10 arranged around the vent holes 9 according to the tabletop layout. The bottom layer has openable and closable valves 8 located below the corresponding vent holes 9.

[0044] Each of the aforementioned valves 8 includes an actuator and six blades 12, see [link / reference]. Figure 5As shown, the blade 12 is connected to the actuator via a rotating shaft 11. The actuator is composed of an electromagnet (or a solenoid valve, motor). After receiving the sensing signal from the pressure sensor 10 and performing comparison calculations, the controller selects the corresponding position of the valve actuator to drive the blade 12 to move, thus opening the negative pressure intake channel from the vent hole 9 on the upper working surface 6 to the air outlet on the lower surface.

[0045] Its active dust reduction method is as follows: A negative pressure balance control device 5 is installed below the clean operation area 13. When an object is placed on the upper working surface 6, the pressure sensor 10 of the middle layer 7 receives the gravity sensing and transmits the sensing signal to the bottom valve controller. The controller determines the specific location of the sent sensing signal through a comparator and drives the actuator 11 at the corresponding location to open the blade 12, so that the ventilation hole 9 at the object placement location is connected to the return air area below, forming a local negative pressure suction channel to quickly absorb the pollutant airflow emitted by the object; in areas where no object is placed, the valve 8 is closed and the airflow is normal.

[0046] When determining the position of pressure sensor 10, each pressure sensor 10 can be numbered, such as in coordinate form (X,Y). A corresponding execution number is assigned to valve 8 for each pressure sensor 10 position number. The controller pre-stores an initial pressure value for each position number. When the measured pressure value exceeds the initial pressure value, it is determined that the position number corresponds to an object placement location, and the corresponding execution number valve 8 is activated, opening the blade 12. Valves 8 in other areas remain closed, providing localized air extraction and ventilation to reduce the spread of contaminants while ensuring airflow cleanliness with minimal energy consumption.

[0047] Furthermore, the opening degree of the valve 8 can be adjusted by controlling the rotation angle of the blade 12, thereby controlling the ventilation volume and achieving the optimal balance between energy consumption and cleanliness performance.

[0048] Experimental testing of dust reduction effect: Taking a clean bench with horizontal air outlet as an example, the size of the Class 5 (Class 100) work area is 820 (width) × 600 (height) × 480 (depth) mm, and the air outlet surface is 820 (width) × 600 (height) mm.

[0049] 1. Detection data of empty state conditions

[0050] a) According to the testing requirements, first scan the HEPA filter to ensure there are no leaks. Then, at a distance of 150mm from the air outlet surface of the HEPA filter's front mesh panel, take the intersection of the two diagonals as point 3. Using this intersection as the starting point, take the midpoints of the four lines connecting to the four corners to form sampling points 1, 2, 4, and 5. Figure 6 As shown in Table 1. Detection data under empty state conditions (unit: particles / liter):

[0051] sequence Particle size 1 2 3 4 5 1 0.5μm 0 0 0 0 0 2 5μm 0 0 0 0 0

[0052] Standard requirement: ≤3.5 particles / L of particles ≥0.5μm at each measuring point.

[0053] Particles ≥5μm ≤0 particles / L

[0054] Test results: Meets the requirements of Class 5 (100).

[0055] 2. Static condition test data

[0056] a) Place the two containers containing volatile aerosols in the work area (near or before measuring point 4), and cover them to ensure no volatile aerosols overflow. Place the larger container 80mm from the air outlet and the smaller container 250mm from the air outlet.

[0057] A dust particle counter sampling tube was placed 150mm away from the air outlet surface for sampling and testing.

[0058] Table 2. Test data with container lid on, 150mm from the air outlet surface at static distance (unit: particles / liter)

[0059] sequence Particle size 1 2 3 4 5 1 0.5μm 0 0 0 1 0 2 5μm 0 0 0 0 0

[0060] Test results: Meets the requirements of Class 5 (100).

[0061] b) Place the container containing the volatile aerosol in the work area (near measuring point 4), open the lid, and allow the volatile aerosol in the larger container to overflow. Place the larger container 80mm away from the air outlet and the smaller container 200mm away from the air outlet, then close the lid.

[0062] At this point, the bottom valve of the honeycomb platform is closed and not open. Although the weight of the two containers has triggered the pressure sensor, manually closing the valve will not generate a downward airflow.

[0063] Table 4. Test data for a large container with its lid open and valve closed at a static distance of 150mm from the air outlet (unit: particles / liter).

[0064] sequence Particle size 1 2 3 4 5 1 0.5μm 0 0 0 1549 0 2 5μm 0 0 0 108 0

[0065] Test result: Does not meet the requirements of class 5 (100).

[0066] This state is exactly the same as the current horizontal clean bench without ventilation doors. Simulating the working conditions of a traditional clean bench, the concentration of ≥0.5μm particles at measuring point 4 under the same pollution source can reach 1549 particles / liter, far exceeding the standard limit, which verifies the effectiveness of this solution in controlling pollution.

[0067] Since the sample taken at 150mm from the air outlet did not meet the cleanliness level 5 requirement, the sampling test at 350mm from the air outlet was not conducted.

[0068] 3. Static detection data (e.g.) Figure 2 (as shown in the image)

[0069] a) Place the container containing the volatile aerosol in the work area (near measuring point 4), open the lid, and ensure that volatile aerosols overflow. Place the larger container 80mm away from the air outlet and the smaller container 200mm away from the air outlet, then close the lid.

[0070] At this point, the weight of the large container triggers a pressure sensor to open the valves around the platform, allowing the emitted aerosols to be rapidly drawn downwards through the suction channel beneath the platform, effectively reducing the spread of contamination.

[0071] Table 5. Test data for a large container with its lid and valve open, at a static distance of 150mm from the air outlet (unit: particles / liter).

[0072] sequence Particle size 1 2 3 4 5 1 0.5μm 0 0 0 2 0 2 5μm 0 0 0 0 0

[0073] Test results: Meets the requirements of Class 5 (100).

[0074] Increase sampling and detection at a distance of 350mm from the air outlet.

[0075] Table 6. Test data for large and small containers with open lids and corresponding valves at a static distance of 350mm from the air outlet (unit: particles / liter).

[0076] sequence Particle size 1 2 3 4 5 1 0.5μm 0 0 0 3 0 2 5μm 0 0 0 0 0

[0077] Test results: Meets Class 5 (100-level) requirements

[0078] Based on the above test results and analysis of six test data sets (Tables 1-6), it was further confirmed that the clean bench equipped with a negative pressure balance control device can actively ventilate, verifying the effectiveness of removing contaminating aerosols.

[0079] In actual operation, the controller can also adaptively adjust the main fan speed according to the number of valves opened at the same time, so as to achieve the lowest energy consumption operation while ensuring cleanliness.

[0080] In another embodiment, the negative pressure balance control device is an independent structure, including a shell, with the upper working surface, middle layer and bottom layer stacked sequentially inside the shell. A first negative pressure chamber is provided under the operating table. The operating table is connected to the cabinet through a detachable structure. When the negative pressure balance control device is used, the negative pressure balance control device replaces the operating table. The negative pressure balance control device is located in the first negative pressure chamber. The object to be measured is placed on the upper working surface. The bottom air outlet is connected to the inlet of the return air zone.

[0081] In this embodiment, the negative pressure balance control device is an optional accessory that can be replaced with the operating table through a detachable structure when needed, so as to meet the environmental needs of different items under different usage conditions and is flexible and adaptable.

[0082] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A clean workbench with active dust suppression function, comprising a cabinet, a work surface, a high-efficiency air filter, and a fan, wherein the outlet of the high-efficiency air filter blows clean air into the work surface to form a clean operating area, and the area below the work surface is a return air area, wherein the fan is located in the return air area, characterized in that: A negative pressure balance control device is installed below the clean operating area. It has a three-layer honeycomb perforated structure, including an upper working surface with perforations, a middle layer with a plurality of pressure sensors, and a bottom layer consisting of a plurality of valves. The air outlet of the bottom layer is connected to the return air area. The upper working surface is an operating platform for carrying items, and a plurality of ventilation holes that connect to the middle layer below are evenly distributed on it. The pressure sensors are arranged in an array around the vents on the intermediate layer according to the distribution of the vents above. The pressure sensors receive the sensing signals transmitted by the upper working surface. A valve is provided on the bottom layer according to the location of the vent hole. The valve opens or closes upon receiving a sensing signal from the pressure sensor.

2. The clean workbench with active dust reduction function according to claim 1, characterized in that: Each of the valves includes an actuator and several blades. After receiving the sensing signal from the pressure sensor and performing comparison calculations, the controller selects the valve actuator at the corresponding position to drive the blades to move, thus opening the negative pressure air intake channel from the vent on the upper working surface to the air outlet at the bottom.

3. The clean workbench with active dust reduction function according to claim 2, characterized in that: The blade is connected to the actuator via a rotating shaft. The actuator is composed of an electromagnet, a solenoid valve, or a motor.

4. The clean workbench with active dust reduction function according to claim 1, characterized in that: The negative pressure balance control device includes a housing, with the upper working surface, middle layer, and bottom layer stacked sequentially inside the housing. A first negative pressure chamber is provided under the operating table. The operating table is connected to the cabinet via a detachable structure. When the negative pressure balance control device is used, it replaces the operating table. The negative pressure balance control device is located in the first negative pressure chamber. The object to be measured is placed on the upper working surface. The bottom air outlet is connected to the inlet of the return air zone.

5. The active dust reduction method for a clean bench according to claim 1, characterized in that: A negative pressure balance control device is installed below the clean operating area. When an object is placed on the upper working surface, the pressure sensor in the middle layer receives gravity sensing and transmits the sensing signal to the valve controller at the bottom layer. The controller determines the specific location of the sensing signal through a comparator and drives the valve actuator at the corresponding location to open the blades, so that the ventilation hole at the object placement location is connected to the return air area below, forming a local negative pressure suction channel to quickly absorb the pollutant airflow emitted by the object. In areas where no objects are placed, the valve is closed, allowing normal airflow.

6. The active dust suppression method according to claim 5, characterized in that: The pressure sensors are arranged in a matrix, each corresponding to a position number. The valve is assigned an execution number for each pressure sensor position number. The controller stores an initial pressure value for each position number. When the measured pressure value exceeds the initial pressure value, it is determined that the position number is where the object is placed, and the corresponding execution number valve is driven to open the blade.

7. The active dust suppression method according to claim 5 or 6, characterized in that: Several blades are arranged in a ring and connected to the actuator via a rotating shaft. The controller drives the actuator to rotate the rotating shaft and controls the opening degree of the valve by setting the rotation angle.

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