Centralized oil mist treatment system with self-cleaning prefilter

Abstract

The invention relates to the technical field of oil mist purification of machining workshops, in particular to an oil mist centralized treatment system with a self-cleaning prefilter. Comprising an air pipe system, a prefilter, a cyclone separator and a main fan. The air pipe system is composed of a plurality of branch air pipes and a main air pipe and used for conveying oil mist generated by all the oil mist source devices to the pre-filter in a centralized mode. The prefilter is provided with an air duct area and a cleaning tank area, is provided with a filter plate with switchable positions, is matched with a driving mechanism to move between an air duct and a cleaning tank, and realizes automatic cleaning by means of an ultrasonic cleaning device and a jet cleaning nozzle. The pre-filtered gas enters a cyclone separator, fine particles and water are further removed, and then the gas is extracted by a main fan. The system can efficiently remove oil mist, reduce the load of subsequent equipment and improve the purification efficiency and the operation stability.

Description

Technical Field

[0001] The invention relates to the technical field of oil mist purification in a machining workshop, and in particular to an oil mist centralized treatment system with a self-cleaning pre-filter. Background Art

[0002] During machining processes such as cutting, painting, and stretching, oily substances are often used. These oily substances are easily atomized during the machining process and mixed with air to form oil mist, which floats in the workshop air, causing environmental pollution and posing a threat to workers' health.

[0003] Traditional oil mist treatment methods typically involve installing exhaust fans on the ceiling of the workshop, which discharge the oil-laden air directly into the outside environment without filtration, easily causing air pollution. Furthermore, the oil mist diffuses throughout the workshop, not only affecting worker health but also depositing on equipment surfaces, shortening equipment life and increasing maintenance costs.

[0004] Some modern workshops utilize centralized exhaust systems, discharging oil mist through ducts. However, due to the high concentration of oil mist, it easily deposits on the duct walls and fan impellers, causing fan failure and reduced ventilation efficiency, further exacerbating the difficulty of oil mist treatment. Therefore, there is an urgent need for a highly efficient, low-maintenance centralized oil mist treatment technology to improve workshop environmental quality and system operational stability. Summary of the Invention

[0005] In response to the above-mentioned deficiencies or defects in the prior art, the present invention provides a centralized oil mist treatment system with a self-cleaning pre-filter. The system centrally collects the oil mist generated by various equipment on the production line, removes most of the oil particles through the self-cleaning pre-filter, and significantly reduces the equipment maintenance frequency and failure rate.

[0006] To achieve the above-mentioned object, the present invention provides a centralized oil mist treatment system with a self-cleaning pre-filter, comprising: an air duct system including a main air duct and a plurality of branch air ducts, one end of the branch air duct being connected to an oil mist generating device and the other end being connected to the main air duct; an air outlet of the main air duct being directly connected to the pre-filter;

[0007] The pre-filter includes a housing, a filter plate, a drive mechanism, and a cleaning device. The upper half of the housing is an air duct area, and the lower half is a cleaning tank area. The housing at both ends of the air duct area has an air inlet and an air outlet. The cleaning tank area is filled with cleaning liquid. Several filter plates are provided in the pre-filter to filter oil particles in the oil mist.

[0008] A driving mechanism drives the filter plate to switch between the air duct area and the cleaning tank area;

[0009] A cleaning device, including an ultrasonic cleaning device and a jet cleaning nozzle, is used to clean the filter plate located in the cleaning tank area;

[0010] a cyclone separator, the air inlet of which is connected to the air outlet of the pre-filter;

[0011] The main fan has an air inlet connected to the air outlet of the cyclone separator.

[0012] In some embodiments, the system further comprises:

[0013] The air inlet of the secondary filter is connected to the air outlet of the main fan;

[0014] an activated carbon adsorber, the air inlet of which is connected to the air outlet of the secondary filter;

[0015] The secondary filter is a bag filter and / or a centrifugal separator and / or an electrostatic adsorber.

[0016] In some embodiments, the branch air ducts are each provided with an induced draft fan to deliver the oil mist generated by the oil mist generating device into the branch air duct and then into the main air duct.

[0017] The induced draft fan is linked to the oil mist generating device connected to the branch air duct, and when the oil mist generating device starts to generate oil mist, the induced draft fan is started.

[0018] In some embodiments, the air outlet of the pre-filter is connected to the air inlet of the cyclone separator via a U-shaped pipe. The downward bend of the U-shaped pipe forms a liquid sump, and a drain port is provided at the bottom of the liquid sump. The drain port is connected to a liquid seal device to prevent air leakage.

[0019] In some embodiments, the jet direction of the jet cleaning nozzle is opposite to the air flow direction in the air duct area.

[0020] In some embodiments, the system further comprises:

[0021] The filtration system includes a circulation pump and a filtration device. The circulation pump is connected to the bottom of the cleaning tank area through a pipeline. The outlet of the circulation pump is connected to the filtration device. The water outlet of the filtration device is connected to the cleaning tank area.

[0022] The rehydration system includes a mixing tank and a rehydration pump. The mixing tank mixes the solution and the degreasing agent to form a cleaning liquid, and the cleaning liquid is injected into the cleaning tank area through the rehydration pump;

[0023] Liquid level sensor, set in the cleaning tank area to detect the liquid level;

[0024] An oil scraper is provided at the top liquid level of the cleaning tank area;

[0025] Drain port: a drain port is provided in the cleaning tank area of ​​the shell.

[0026] In some embodiments, the housing is in the shape of a horizontal square cylinder, and vertically extending guide rails are provided on both the left and right sides of the housing;

[0027] The filter plate is square, and the left and right sides of the filter plate are respectively slidably arranged on the guide rails; multiple filter plates are provided;

[0028] The driving mechanism is a lifting driver, which connects the housing and the filter plate and drives the filter plate to move up and down; the driving mechanism corresponds to the filter plate one by one.

[0029] In some embodiments, the filter plate has a filtering station that moves upward to the top of the guide rail and is located in the air duct area;

[0030] and,

[0031] A cleaning station is provided which moves downward to the bottom of the guide rail and is located in the cleaning tank area;

[0032] In the filtering station, the filter plate is pressed tightly against the top of the shell, and the bottom of the filter plate is inserted below the liquid level; in the cleaning station, the filter plate is located below the liquid level as a whole, and only one filter plate is allowed to enter the cleaning station at any time.

[0033] In some embodiments, the pre-filter housing is a horizontal cylindrical structure, with the upper half being the air duct area and the lower half being the cleaning tank area;

[0034] The filter plate is disc-shaped and fits the inner diameter of the housing;

[0035] The driving mechanism includes a motor and a rotating shaft. The motor drives the rotating shaft to rotate. The filter plate is fixed on the rotating shaft. The metal filter plate rotates around the inner axis of the cylinder to realize the switching of the filter plate fan between the air duct area and the cleaning tank area.

[0036] The application of the above technical solution of the present invention to a centralized oil mist treatment system with a self-cleaning pre-filter has the following effects:

[0037] The present invention uses a centralized air duct system to collect and transport the oil mist generated by various production equipment to the pre-filter, achieving efficient interception and purification of the oil mist. It has the following significant advantages:

[0038] High-efficiency primary interception: the pre-filter adopts a metal filter plate structure and a self-cleaning mechanism, which can intercept most oil particles (especially oil droplets with larger diameters) during the filtration process, significantly reducing the particle load entering the back-end processing unit and extending the service life of equipment such as the cyclone separator and the main fan.

[0039] The intelligent self-cleaning design divides the pre-filter into an air duct area and a cleaning tank area. The metal filter plates are automatically transferred to the cleaning tank by a lifting or rotating mechanism for ultrasonic and jet cleaning. After cleaning, they are quickly returned to the air duct to participate in filtration. This online self-cleaning method effectively avoids the frequent replacement of traditional filter media due to oil clogging, significantly reducing maintenance costs and labor intensity, and ensuring long-term continuous operation of the system.

[0040] Gradual, deep purification: After pre-filtration, the airflow, which only contains small-diameter oil particles, enters a cyclone separator for further removal of fine oil droplets and moisture. This is followed by an electrostatic adsorber, centrifugal demister, or activated carbon adsorber for further treatment. This ensures that the final exhaust air consistently meets environmental standards, fully safeguarding operator health and workshop air quality.

[0041] In summary, the present invention integrates physical interception, self-cleaning and multi-stage deep treatment, which not only greatly improves the oil mist removal efficiency and system reliability, but also reduces maintenance costs and equipment failure rate, with significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is an overall schematic diagram of the centralized oil mist treatment system with a self-cleaning pre-filter of the present invention;

[0043] Figure 2 It is a schematic diagram of how the driving mechanism drives the filter plate in the second embodiment of the pre-filter.

[0044] Description of Reference Numerals

[0045] 1- Duct system, 1a- Main duct, 1b- induced draft fan;

[0046] 2-pre-filter, 2a-housing, 2b-filter plate, 2c-track;

[0047] 3- driving mechanism;

[0048] 4- Cyclone separator;

[0049] 5- Main fan;

[0050] 6-Secondary filter;

[0051] 7-activated carbon adsorber;

[0052] 8-U-type pipe;

[0053] 9- Filtration system;

[0054] 10-Fluid replenishment system;

[0055] 11-Oil mist generating equipment. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0058] The "oil mist" targeted by this invention refers to a mixture of large amounts of liquid pollutant particles and air. These liquid pollutants can be water droplets, cutting oil, wet paint, ink, and so on. Large amounts of oil mist are generated during cutting, die drawing, and painting operations. This invention also filters solid particles mixed in the oil mist.

[0059] The "oil mist generating device 11" is not part of the present invention, but is the service object of the filtering and exhaust system of the present invention. The oil mist generating device 11 can refer to any equipment in the workshop that generates oil mist and requires exhaust treatment of the oil mist. For example, machine tools, paint spray booths, paint spray cabinets, inkjet machines, etc. When the machine tool is cutting, the cutting tool will break up the cutting fluid into atomized form and mix it with air to form oil mist; the unattached paint in the paint spray booth or paint spray cabinet will diffuse in the paint spray booth or paint spray cabinet to form oil mist. There are many devices that generate oil mist in mechanical processing, and this article will not list them one by one.

[0060] In conventional centralized oil mist treatment systems, when faced with large amounts of oil mist generated and a large number of oil mist generating devices 11, the fans are easily damaged and the filter elements are easily clogged, requiring frequent replacement or manual cleaning, resulting in high maintenance costs.

[0061] like Figure 1As shown, the present invention provides a centralized oil mist treatment system with a self-cleaning pre-filter. The system primarily comprises an air duct system 1, a pre-filter 2, and a downstream treatment system. The air duct system 1 centrally collects and transports the oil mist generated by each oil mist generating device 11. The pre-filter 2 intercepts and filters the vast majority of oil particles, particularly those with large diameters. This reduces the pressure in the downstream treatment system. The downstream treatment system then purifies the oil mist, removing contaminants (oil droplets, water mist, and small amounts of solid contaminants) and odors before discharging it into the air.

[0062] The air duct system 1 serves as the front-end core structure of the centralized oil mist treatment system with a self-cleaning pre-filter 2 of the present invention. It is mainly responsible for quickly and effectively collecting the oil mist generated by the oil mist source (such as CNC machine tools, punching machines, injection molding machines, heat treatment equipment, etc.) and transporting it to the subsequent processing module.

[0063] The air duct system 1 includes a main air duct 1a and multiple branch air ducts. The main air duct 1a is responsible for unifying and collecting the oil mist gas transmitted by all branch air ducts. The main air duct 1a is usually a main pipeline arranged horizontally above the workshop or on the side wall. The material can be stainless steel or galvanized steel plate, and the cross-section can be rectangular or circular. It can be flexibly designed according to the layout of the workshop. The end of the main air duct 1a is directly connected to the air inlet of the pre-filter 2. A check valve, anti-backflow port, fire damper, etc. can be set at the connection between each branch air duct and the main air duct 1a to prevent backflow of air flow.

[0064] One end of the branch duct is connected to one or a group of oil mist generating devices 11, and the other end merges into the main duct 1a. Branch ducts typically feature a combination of flexible and rigid structures. Oil- and heat-resistant metal hoses are used near the equipment, while rigid metal pipes are used in the rear section. A primary anti-drip screen or oil barrier can be installed within the branch duct as needed to prevent the backflow of large droplets.

[0065] Each branch duct is equipped with an independent induced draft fan (1b) to provide negative pressure to extract oil mist. Each duct's induced draft fan (1b) and its connected oil mist device are electronically controlled. When the device starts generating oil mist, the induced draft fan (1b) automatically starts. When the device shuts down, the induced draft fan (1b) stops after a delay. PLC or relay modules are available for control.

[0066] By installing an induced draft fan (1b) on each branch duct, we effectively address issues such as delayed oil mist collection, low transport efficiency, and large pressure fluctuations in traditional systems. This reduces the amount of oil mist escaping into the production workshop, and reduces the workload of the main fan (5) and duct noise.

[0067] The pre-filter 2 is one of the key components of the centralized oil mist treatment system of the present invention. It is arranged at the end of the main air duct 1a of the air duct system 1 and before the cyclone separator 4. Its main function is to intercept and remove a large number of oil particles, especially oil droplets and oil mist clusters with larger diameters, before the gas enters the subsequent separation and treatment links, thereby significantly reducing the processing burden of the subsequent equipment and extending its service life.

[0068] In order to improve efficiency and continuity of system operation, the pre-filter 2 has self-cleaning ability, which can realize automatic cleaning of the filter element without interrupting the operation of the system, thereby effectively avoiding the problem of increased pressure loss and decreased filtering interception ability caused by clogging of the filter plate 2b due to oil adhesion.

[0069] The housing 2a is cylindrical and horizontally arranged. It is divided into two areas: the upper half is the air duct area, with air inlets and outlets at both ends, allowing air to pass horizontally through the filter plates 2b; the lower half is the cleaning tank area, which is used to hold cleaning fluid and clean the filter plates 2b.

[0070] Multiple filter plates 2b are provided (typically 3-6). These are metal mesh filter plates 2b, offering excellent oil and corrosion resistance and repeatable cleanability. They are positioned in the air duct area, with the plates oriented perpendicular to the airflow. As air passes through the filter plates 2b, they intercept the majority of oil particles.

[0071] The cleaning system is installed in the cleaning tank area. The cleaning system includes an ultrasonic cleaner and a jet cleaning nozzle. When the filter plate 2b enters the cleaning tank, it is started at the same time to perform a full coverage and high-intensity oil stripping treatment on its surface.

[0072] Ultrasonic cleaners are usually composed of ultrasonic transducers, vibration plates, power control systems, etc., and are installed at the bottom or side walls of the cleaning tank area. Some implementations adopt an immersed modular design. The ultrasonic transducer converts high-frequency electrical energy (usually 20-40kHz) into mechanical vibrations, which are transmitted through the cleaning liquid to form a "cavitation effect." Tiny bubbles explode on the surface of the metal filter plate 2b, generating instantaneous high pressure and micro-jets to peel off oil stains and particulate deposits. The ultrasonic cleaner can clean without dead angles and is suitable for metal filters with complex porous structures. It does not mechanically damage the surface of the filter plate 2b, and can ensure the long-term use of the filter plate 2b.

[0073] The jet cleaning nozzle sprays high-pressure cleaning fluid onto the surface of the filter plate 2b at high speed, creating shear force that washes away adherent oil. This complements ultrasonic cleaning and is suitable for removing thick sludge or particulate contaminants. The jet cleaning nozzle is located on the side of the cleaning tank near the air outlet. Its jet flow is directed oppositely from the airflow in the duct, facilitating the removal of accumulated dirt and improving particle desorption efficiency. The jet cleaning nozzle is connected to a high-pressure pump and can be opened and closed by a solenoid valve.

[0074] The drive mechanism 3 is used to drive the filter plate 2b to automatically switch between the air duct area (filtering station) and the cleaning tank area (cleaning station). Depending on the structure, the drive mechanism 3 is a lifting drive assembly or a rotating drive mechanism, which will be described in detail in the embodiments below.

[0075] The auxiliary system is used to maintain the normal operation of the self-cleaning function of the pre-filter 2, including the filtering system 9, the liquid replenishing system 10, the liquid level detector, the oil scraper, the drain port and other auxiliary components to achieve closed-loop management of the cleaning fluid.

[0076] The filtration system 9 includes a circulation pump and a filtration device. The circulation pump draws the used cleaning fluid from the bottom of the cleaning tank and feeds it into the filtration device. The filtration device physically separates the sludge, particulate matter, and other impurities from the cleaning fluid (e.g., using a multi-stage filter element or gravity separation). The treated cleaning fluid then flows back into the cleaning tank for further cleaning of the filter plates 2b.

[0077] The refill system 10 includes a mixing tank, a refill pump, and connecting piping. The mixing tank is pre-filled with a cleaning solution consisting of a degreasing agent and water. The refill pump injects fresh cleaning solution into the cleaning tank at a fixed or fixed rate based on system instructions or feedback from a liquid level sensor. The refill process is automatically controlled by a solenoid valve, eliminating the need for manual intervention.

[0078] The liquid level sensor, installed in the cleaning tank, monitors the cleaning fluid level in real time. It can be a float, ultrasonic, or capacitive type. When the liquid level falls below a set lower limit, the refill pump automatically activates. When the liquid level rises above a set upper limit, the system issues an alarm or stops refilling. This effectively prevents excess liquid from causing overflow or insufficient liquid from affecting cleaning results.

[0079] The oil scraper, located above the liquid level in the cleaning tank, includes an oil collection mechanism and a scraping drive mechanism (e.g., a motorized scraper and a floating ball swing arm). Over time, oil accumulates on the cleaning tank surface. The oil scraper is activated periodically to remove the surface oil to a nearby oil collection tank for centralized discharge. This effectively minimizes the impact of oil on the cleaning process and secondary contamination of the filter plate 2b, reducing the workload of manual oil removal and maintaining the self-cleaning function for extended periods.

[0080] A drain port is located at the bottom of the cleaning tank to drain waste liquid. It is linked to the refill system 10 to regularly refresh the cleaning liquid. A hose can be connected to the drain port to lead to a centralized sewage treatment area. A drain pump and valve are installed at the drain port.

[0081] Implementation method 1: lifting pre-filter

[0082] The outer shell 2a is a horizontal square box structure with vertical guide rails on both sides. The filter plate 2b is a square structure with both side edges embedded in the guide rails. The width of the filter plate 2b is the same as the width of the outer shell 2a, and the height of the filter plate 2b is half the height of the outer shell 2a. Figure 2 As shown, the drive mechanism 3 is a lifting drive (vertically arranged cylinder, electric push rod, and winch arranged on the top of the housing 2a). Each filter plate 2b is equipped with an independent lifting drive and can be freely raised and lowered in the vertical direction to switch between the filtering station and the cleaning station.

[0083] Filtration Station: A lift actuator drives filter plate 2b up to the air duct area, where its top is firmly pressed against housing 2a and its bottom is submerged below the level of the cleaning fluid. Air entering from the air inlet must pass through metal filter plate 2b before reaching the air outlet.

[0084] Cleaning Station: The lift actuator lowers filter plate 2b to the cleaning tank. Completely immersed in the cleaning fluid, filter plate 2b undergoes ultrasonic and jet cleaning. The control system activates the actuator for a specific filter plate 2b at a set interval, lowering it to the cleaning tank. Multiple filter plates 2b are cleaned in turn, ensuring continuous filtering operation. After cleaning, the filter plate 2b is raised back to the air duct area to resume filtering.

[0085] Implementation method 2: Rotary pre-filter

[0086] The outer shell 2a is a horizontal cylindrical structure, with the upper half being the air duct and the lower half being the cleaning tank. The filter plate 2b is a disc-shaped metal filter plate 2b that fits the inner diameter of the cylinder. Multiple filter discs are arranged radially along the axis of the cylinder. The driver includes a motor and a rotating shaft. The rotating shaft is rotatably mounted on the outer shell 2a along the central axis of the outer shell 2a and is driven by the motor. The filter plate 2b is fixed to the rotating shaft and rotates around the axis of the cylinder. The upper half of the filter plate 2b is located in the air duct area (interception station), and the lower half is located in the cleaning tank area (cleaning station).

[0087] A circular track 2c may also be provided on the inner wall of the housing 2a around the circumference of the housing 2a. The track 2c fits with the outer circumference of the filter plate 2b to reduce airflow escaping from the gap between the filter plate 2b and the housing 2a.

[0088] Filtration station: Multiple filter plates 2b are fan-shaped and distributed in the air duct area, perpendicular to the airflow direction. Air enters from the air inlet at one end, passes through the fan-shaped filter area, and flows out from the air outlet at the other end, and oil is trapped on the plate surface.

[0089] Cleaning Station: The control system controls the motor's rotation based on a timer or pressure loss threshold, rotating the fan-shaped surfaces of the multiple disc-mounted filter plates 2b to the cleaning tank below. The filter plates 2b are immersed in the cleaning solution and cleaned with ultrasound and jets. Simultaneously, the cleaned fan-shaped surfaces of the filter plates 2b rotate synchronously back to the air duct area.

[0090] This solution offers a compact structure and small footprint, making it suitable for space-constrained applications. Furthermore, with few moving parts, only the shaft needs to rotate, it offers high reliability. Its continuous rotation and high transposition efficiency make it suitable for high-frequency operation.

[0091] In order to further improve the system's purification effect on oil mist and reduce the burden on the main fan 5, the present invention sets a cyclone separator 4 after the pre-filter 2. This device is used to perform secondary separation of residual oil mist particles and part of the water in the air flow, and is one of the key links in the multi-stage purification structure of this system.

[0092] The air inlet of the cyclone separator 4 is directly connected to the air outlet of the pre-filter 2; the air outlet is connected to the air inlet of the main fan 5, and the air is driven through the cyclone separator 4 by the negative pressure generated by the main fan 5.

[0093] The cyclone separator 4 is an overall cylindrical or conical metal structure with a spiral guide channel inside and a liquid collection tank or sewage collection bin at the lower end for collecting the separated oil-water mixture. The cyclone separator 4 mainly uses the principle of centrifugal force to separate gas and liquid. The gas containing oil mist and water vapor enters the cyclone cavity at high speed from the tangential air inlet and rotates along the wall inside the cavity. Due to the strong centrifugal force generated by the rotation of the air flow, the denser oil mist particles and water droplets are thrown to the wall of the device and slide down to the bottom collection bin under the action of gravity. The relatively clean air flows upward from the low-pressure area formed in the center, is sucked out by the main fan 5 through the air outlet, and enters the subsequent deep processing unit.

[0094] On the basis that the pre-filter 2 has removed most of the large particles of oil, the cyclone separator 4 further intercepts small and medium-sized oil droplets to enhance the overall oil removal effect.

[0095] Because pre-filter 2 has a self-cleaning function, filter plate 2b re-enters the filtration process after soaking and cleaning, which may cause the treated airflow to contain some water vapor or droplets. Cyclone separator 4 can effectively remove these droplets, preventing main fan 5 from getting damp or condensing, extending motor life and improving system stability.

[0096] The cyclone separator 4 is a mechanical separation device with no moving parts and a long maintenance cycle. It is also independent of filter media and does not consume chemicals, making it suitable for continuous operation and harsh working conditions.

[0097] A U-shaped pipe 8 connects the air outlet of pre-filter 2 and the air inlet of cyclone separator 4. To accommodate the increased moisture content of the airflow caused by the self-cleaning function of pre-filter 2 in the present invention, and to prevent droplets from directly entering cyclone separator 4 with the airflow and causing system abnormalities, the present invention provides a U-shaped connecting pipe between pre-filter 2 and cyclone separator 4, with a drainage structure at its bottom.

[0098] The connecting pipe has a downwardly curved U-shaped structure, connecting the outlet of the pre-filter 2 and the inlet of the cyclone separator 4 at either end, with the center curving downward to form its lowest point. A drain port is provided at the bottom of the U-shaped pipe 8 to remove the deposited liquid oil-water mixture. The drain port is connected to a liquid seal device or a one-way valve to prevent gas backflow or leakage, ensuring system sealing and safe operation.

[0099] The water-laden gas exits the pre-filter 2 and passes through a U-shaped connecting section before entering the cyclone separator 4. Due to gravity, some liquid droplets, water droplets, and oil contaminants entrained in the airflow settle to the bottom of the U-shaped section. As operation increases, liquid gradually accumulates at the bottom. This liquid can be regularly discharged through the drain port, ensuring that the gas entering the cyclone separator 4 is drier and cleaner, thereby improving separation efficiency and extending the life of the main fan 5.

[0100] The main fan is located after cyclone separator 4 and connected to its outlet. It provides stable suction power for the entire duct system 1, maintaining negative pressure airflow and ensuring that oil mist is efficiently extracted from its source to the treatment device. When the main fan 5 is operating, a negative pressure zone is formed at its front end, pulling the air flow within the system from the branch duct, main duct 1a, pre-filter 2, U-shaped connecting pipe, cyclone separator 4, and then main fan 5 in a step-by-step manner. This helps capture the oil mist from its source and transport it to various levels of treatment devices.

[0101] The main fan 5 provides positive pressure for air flow to the subsequent treatment system, driving the air flow from the main fan 5 → the secondary filter 6 → the activated carbon adsorber 7 → the atmosphere.

[0102] The secondary filter 6 is arranged after the main fan 5 and is located in the terminal purification section of the system. Its main function is to deeply filter the small-diameter oil particles and fine droplets remaining in the air flow to ensure that the discharged air meets environmental protection standards.

[0103] The air inlet of the secondary filter 6 is connected to the air outlet of the main fan 5. The air outlet is connected to the activated carbon adsorber 7, or it can be discharged directly. The secondary filter 6 can be a bag filter, a centrifugal separator, an electrostatic adsorber, or a vacuum cleaner.

[0104] The secondary filter 6 can be composed of a plurality of different filter devices connected in series. Different filters can be combined in series as needed to achieve graded treatment and improve purification efficiency.

[0105] The activated carbon adsorber 7 is the final odor control device of the entire system and is installed at the end of the air outlet of the secondary filter 6. Its main function is to adsorb residual organic odor molecules and volatile organic compounds in the gas, improve exhaust quality, eliminate gas odor, and improve the air environment in the working area.

[0106] The activated carbon adsorber 7 utilizes the large surface area and rich microporous structure of activated carbon to physically adsorb residual organic vapor pollutants in the gas. It is suitable for removing low-concentration odors from a variety of industrial organic waste gases, especially those from emulsion mist, cutting fluid vapor, and other odorous substances.

[0107] System airflow direction: oil mist generating equipment 11 → induced draft fan 1b → branch air duct → main air duct 1a → pre-filter 2 → cyclone separator 4 → main fan 5 → secondary filter 6 (bag / electrostatic / centrifugal) → activated carbon adsorber 7 → exhaust port.

[0108] Through the above scheme:

[0109] The pre-filter 2 is installed at the first stage when the oil mist enters the treatment system. The metal filter plate 2b efficiently intercepts most of the large particles of oil mist, greatly reducing the processing pressure of subsequent equipment such as the cyclone separator 4, the secondary filter 6, and the activated carbon adsorber 7. This not only extends the service life of subsequent equipment, but also reduces overall energy consumption and maintenance frequency.

[0110] The pre-filter 2 is the part with the heaviest load and most prone to clogging in the system. The present invention adopts a self-cleaning design. The filter plate 2b is periodically sent to the cleaning tank area for ultrasonic and jet cleaning through a lifting or rotating structure to achieve online regeneration, avoiding the problem of equipment shutdown or efficiency reduction due to filter material clogging, and significantly enhancing the system's continuous and stable operation capability.

[0111] This system adopts a multi-stage series purification mode of pre-filter 2, cyclone separator 4, secondary filter 6, and activated carbon adsorber 7. It can intercept large particles of oil mist at the source, remove fine particles and odor at the end, and grade the oil particles of different diameters to achieve comprehensive control of oil mist pollution.

[0112] The installation of induced draft fans (IDFs) 1b on the branch ducts prevents oil mist from escaping into the production workshop environment. IDFs 1b are linked to the oil mist source equipment and automatically activate when oil mist is generated. This enables precise extraction and on-demand control, avoiding energy waste and improving system efficiency.

[0113] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A centralized oil mist treatment system with a self-cleaning pre-filter, characterized in that: include: An air duct system (1) includes a main air duct (1a) and a plurality of branch air ducts, one end of the branch air duct is connected to an oil mist generating device (11), and the other end is connected to the main air duct (1a); the air outlet of the main air duct (1a) is directly connected to a pre-filter (2); The pre-filter (2) comprises a housing (2a), wherein the upper half of the housing (2a) is an air duct area, and the lower half is a cleaning tank area; the housing (2a) at both ends of the air duct area is provided with an air inlet and an air outlet; the cleaning tank area is filled with cleaning liquid; a plurality of filter plates (2b) are provided in the pre-filter (2) for filtering oil particles in the oil mist; A driving mechanism (3) drives the filter plate (2b) to switch between the air duct area and the cleaning tank area; A cleaning device, comprising an ultrasonic cleaning device and a jet cleaning nozzle, for cleaning the filter plate (2b) located in the cleaning tank area; a cyclone separator (4), the air inlet of which is connected to the air outlet of the pre-filter (2); The main fan (5) has an air inlet connected to the air outlet of the cyclone separator (4).

2. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The system further comprises: A secondary filter (6), the air inlet of which is connected to the air outlet of the main fan (5); an activated carbon adsorber (7), the air inlet of which is connected to the air outlet of the secondary filter (6); The secondary filter (6) is a bag filter and / or a centrifugal separator and / or an electrostatic adsorber.

3. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The branch air ducts are each provided with an induced draft fan (1b) to send the oil mist generated by the oil mist generating device (11) into the branch air duct and then into the main air duct (1a); The induced draft fan (1b) is linked to the oil mist generating device (11) connected to the branch air duct. When the oil mist generating device (11) starts to generate oil mist, the induced draft fan (1b) starts.

4. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The air outlet of the pre-filter (2) is connected to the air inlet of the cyclone separator (4) via a U-shaped pipe (8); a liquid sump is formed at the bottom of the downwardly bent portion of the U-shaped pipe (8); a liquid discharge port is provided at the bottom of the liquid sump; and the liquid discharge port is connected to a liquid sealing device to prevent air leakage.

5. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The spraying direction of the jet cleaning nozzle is opposite to the air flow direction of the air duct area.

6. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The system also includes: The filtration system (9) includes a circulation pump and a filtration device; the circulation pump is connected to the bottom of the cleaning tank area through a pipeline, the outlet of the circulation pump is connected to the filtration device, and the water outlet of the filtration device is connected to the cleaning tank area; The liquid replenishing system (10) includes a liquid mixing tank and a liquid replenishing pump; the liquid mixing tank mixes the solution and the degreasing agent to form a cleaning liquid, and the cleaning liquid is injected into the cleaning tank area through the liquid replenishing pump; The liquid level sensor is set in the cleaning tank area to detect the liquid level; An oil scraper is provided at the top liquid level of the cleaning tank area; A liquid drain port is provided in the cleaning tank area of ​​the housing (2a).

7. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The shell (2a) is in the shape of a horizontally placed square cylinder, and vertically extending guide rails are provided on both the left and right sides of the shell (2a); The filter plate (2b) is square, and the left and right sides of the filter plate (2b) are respectively slidably arranged on the guide rails; a plurality of filter plates (2b) are provided; The driving mechanism (3) is a lifting driver, which connects the housing and the filter plate (2b) and drives the filter plate (2b) to move up and down; the driving mechanism (3) corresponds to the filter plate (2b) one by one.

8. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 7, characterized in that: The filter plate (2b) has a filtering station that moves upward to the top of the guide rail and is located in the air duct area; and, A cleaning station is provided which moves downward to the bottom of the guide rail and is located in the cleaning tank area; In the filtering station, the filter plate (2b) is pressed tightly against the top of the housing (2a), and the bottom of the filter plate (2b) is inserted below the liquid level; in the cleaning station, the filter plate (2b) is entirely located below the liquid level, and only one filter plate (2b) is allowed to enter the cleaning station at any one time.

9. The centralized oil mist treatment system with a self-cleaning pre-filter according to claim 1, characterized in that: The housing (2a) of the pre-filter (2) is a horizontal cylindrical structure, the upper half of which is the air duct area and the lower half is the cleaning tank area. The filter plate (2b) is disc-shaped and fits the inner diameter of the housing (2a); The driving mechanism (3) comprises a motor and a rotating shaft. The motor drives the rotating shaft to rotate. The filter plate (2b) is fixed on the rotating shaft. The metal filter plate (2b) rotates around the inner axis of the cylinder to switch the fan surface of the filter plate (2b) between the air duct area and the cleaning tank area.

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