Oil mist purification system and oil mist purification equipment

Abstract

The invention relates to the technical field of separation and purification of pollutants in air, in particular to an oil mist purification system and oil mist purification equipment. Comprising an oil mist interceptor, an electrostatic filter, a gas mixing device, a demister, a fan and a precision filter, the fan is arranged in the middle of the system, a negative pressure working area is formed at the front end of the fan, and a positive pressure working area is formed at the rear end of the fan. Oil mist waste gas from the CNC machine tool firstly passes through the oil mist interceptor to remove large-particle-size oil mist liquid drops and refine particle size distribution, and then enters the electrostatic filter to be subjected to electric field trapping; then the airflow enters a gas mixing device and is mixed with cold air to reduce the temperature, so that part of gaseous pollutants are condensed to form liquid drops, and the liquid drops are separated through a demister; and the treated airflow enters the fan to be pressurized, then enters the precision filter to further filter fine particles, and then is discharged. The purification efficiency of the oil mist waste gas is improved by reasonably configuring all the purification units and utilizing form transformation of pollutants in the treatment process.

Description

Technical Field

[0001] This invention relates to the field of air pollutant separation and purification technology, specifically to an oil mist purification system and oil mist purification equipment. Background Technology

[0002] High-precision CNC machine tools typically require continuous spraying of cutting fluid to cool and lubricate the cutting tools and workpieces during high-speed machining processes such as milling, turning, and grinding. Under the influence of high-speed tool rotation and high cutting temperatures, the cutting fluid is violently agitated and partially vaporized, forming a large amount of mixed exhaust gas inside the machine tool containing oil mist droplets, gaseous hydrocarbons, and fine particulate matter. Direct emission of this exhaust gas not only harms the respiratory health of operators but also easily leads to oil deposits on equipment surfaces, affecting the operating environment and posing safety hazards.

[0003] To reduce the diffusion of oil mist exhaust gas, existing technologies typically enclose the machining area of ​​CNC machine tools and install exhaust ports on the top or side of the machine tool housing. A fan creates negative pressure inside the machine tool to extract the oil mist-containing exhaust gas and send it to subsequent purification equipment for treatment. For the purification of CNC oil mist exhaust gas, the industry generally employs a combination of technologies such as mechanical separation, multi-stage filtration, and electrostatic oil mist purification devices. For example, in some applications with high emission requirements, the oil mist exhaust gas usually passes through multiple treatment units, including centrifugal separators, multi-stage filter cartridges, electrostatic adsorption devices, and activated carbon adsorption devices, before being discharged.

[0004] However, while the above-mentioned treatment methods can achieve good purification results, they still have some shortcomings in practical applications. First, multi-stage filtration and activated carbon adsorption structures usually require regular replacement of filter elements or adsorption materials, resulting in high maintenance frequency and increased system operating costs. If the activated carbon adsorption device is removed, white smoke that is difficult to completely eliminate can easily occur during actual operation, thus affecting the emission effect. Second, in some existing systems, the fan is usually located at the front end of the purification system, directly in contact with high-concentration oil mist gas. After long-term operation, oil and solid particles can easily adhere to the surface of the fan impeller and form stubborn dirt, affecting fan efficiency and even causing equipment failure. If the fan is located at the end of the purification system, making the entire system operate under negative pressure, the system becomes more sensitive to the air resistance of each treatment unit. To ensure sufficient suction capacity inside the machine tool, larger fans are often required, thus increasing equipment energy consumption and costs.

[0005] Therefore, how to reduce the risk of oil mist contamination of the fan while ensuring sufficient suction capacity inside the machine tool, and how to fully consider the changes in the form of pollutants during the oil mist purification process, so as to improve the overall purification efficiency and reduce the system maintenance cost, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide an oil mist purification system and oil mist purification equipment to solve the problem that the oil mist gas generated by existing CNC machine tools and other processing equipment is difficult to purify effectively, especially the problems that small oil mist purification equipment is prone to white smoke emission, difficulty in capturing gaseous oil mist and excessive filtration burden during the processing.

[0007] To achieve the above objectives, the present invention provides an oil mist purification system, comprising an oil mist interceptor, an electrostatic filter, a gas mixing device, a demister, a fan, and a precision filter arranged sequentially along the airflow direction; The oil mist interceptor is used to intercept large-diameter oil mist droplets in oil mist gas. The electrostatic filter is used to remove oil mist droplets from the oil mist gas; The gas mixing device has a main airflow inlet and a cold air inlet, which is used to mix the main airflow after it has been treated by an electrostatic filter with cold air to reduce the airflow temperature and condense gaseous pollutants. The demister is used to remove liquid droplets formed after the gas mixture condenses; The fan is positioned between the demister and the precision filter, so that the oil mist interceptor, electrostatic filter, gas mixing device and demister are in the negative pressure zone at the front end of the fan, and the precision filter is in the positive pressure zone at the rear end of the fan. The precision filter is used to remove solid particles from the airflow.

[0008] In some embodiments, the oil mist interceptor includes a housing, an interception turntable disposed within the housing, and a drive motor for driving the interception turntable to rotate; An airflow channel for the flow of oil mist gas is formed inside the housing. An air inlet and an air outlet are respectively provided at both ends of the airflow channel. When the oil mist gas passes through the rotating intercepting disc, it collides with the intercepting disc, so that the large-diameter droplets in the oil mist are captured and separated from the airflow.

[0009] In some embodiments, the intercepting turntable includes a mounting shaft, a plurality of radially distributed intercepting spokes, and an outer ring frame. The inner ends of the intercepting spokes are fixed to the mounting shaft, and the outer ends are connected to the outer ring frame. A guide groove extending circumferentially is formed on the inner edge of the outer ring frame, and a plurality of guide holes communicating with the outer side of the outer ring frame are provided on the guide groove. This allows oil stains adhering to the intercepting spokes to flow outward along the intercepting spokes under the centrifugal force generated by the rotation of the intercepting turntable into the guide groove and then be thrown out through the guide holes to the inner wall of the housing. The bottom of the shell forms an oil storage tank and is provided with an oil drain port, so that the oil sludge collects along the inner wall of the shell into the oil storage tank and is then discharged. The drive motor is located on the side of the intercepting turntable near the air outlet to reduce the deposition of oil on the drive motor.

[0010] In some embodiments, the electrostatic filter includes a first electrostatic filter for primary coarse filtration and a second electrostatic filter for secondary fine filtration; The electrode spacing of the first electrostatic filter is greater than that of the second electrostatic filter, and the operating voltage of the first electrostatic filter is greater than that of the second electrostatic filter.

[0011] In some embodiments, a coarse filter is provided between the electrostatic filter and the gas mixing device to remove solid particles from the airflow.

[0012] In some embodiments, the gas mixing device includes a main airflow inlet and a cold air inlet, wherein the main airflow inlet is connected to an electrostatic filter, and the cold air inlet is used to introduce workshop air or air conditioning cold air to reduce the temperature of the main airflow and promote the condensation of some gaseous substances into droplets.

[0013] In some embodiments, a multi-leaf regulating valve is provided at the cold air inlet to regulate the flow rate of cold air entering the gas mixing device, thereby controlling the temperature of the mixed airflow; An air filter is also provided at the cold air inlet to remove dust particles from the cold air entering the gas mixing device.

[0014] In some embodiments, the precision filter is a high-efficiency air filter used to precisely filter solid particles in the airflow to eliminate white smoke in the exhaust.

[0015] In some embodiments, the precision filter is an activated carbon filter, or an activated carbon filter is provided downstream of the precision filter to adsorb gaseous organic matter in the airflow.

[0016] The present invention also provides an oil mist purification device, including a device housing and the aforementioned oil mist purification system disposed within the device housing. The device housing is provided with a main airflow inlet for connecting to a CNC machine tool, a cold air inlet for introducing cold air, and an exhaust port, enabling the oil mist purification device to be installed as an independent device next to the CNC machine tool and to treat the oil mist gas discharged from the machine tool.

[0017] Beneficial effects: Compared with existing technologies, the oil mist purification system provided by this invention not only removes oil mist step by step through a multi-stage treatment structure, but also systematically designs the entire purification process from the perspective of the morphological changes of pollutants in the treated airflow, enabling each treatment unit to operate under suitable conditions, thereby significantly improving the overall purification effect. By optimizing the structural layout and treatment mechanism of the oil mist treatment process, a gas mixing and condensation treatment mechanism is introduced into the small-scale oil mist purification equipment, enabling the effective conversion and removal of gaseous oil mist, thereby significantly improving the oil mist purification effect. Its main beneficial effects are as follows: By comprehensively utilizing the transformation of pollutant forms, the removal efficiency of pollutants in oil mist can be improved. Existing oil mist purification equipment typically employs a multi-stage filtration structure, removing oil mist particles step by step through different types of filtration units. However, most of these systems focus only on the direct capture of pollutants, rarely considering the potential morphological changes that pollutants may undergo during treatment. During oil mist treatment, some oily substances may exist in a gaseous or near-gaseous state. These substances are difficult to remove directly using conventional filtration methods and easily form white smoke during exhaust.

[0018] This invention sets up a gas mixing device after the electrostatic filter. By introducing cold air to mix with the main airflow, the airflow temperature is reduced, causing condensable substances in the airflow to condense and form droplets. The droplets are then separated by a subsequent demister, thereby converting gaseous oily substances that are difficult to capture into droplets and removing them, reducing white smoke in the exhaust and improving the oil mist purification effect.

[0019] By leveraging the influence of the treatment equipment itself on the morphology of pollutants, the system's processing flow can be optimized. In oil mist treatment, different treatment devices not only separate pollutants but may also affect the distribution patterns and morphologies of pollutants in the airflow. Oil mist interceptors not only reduce oil mist concentration but also alter the distribution ratio of oil mist particles of different diameters, increasing the proportion of smaller particulate pollutants. Electrostatic filters spontaneously generate solid particles and gaseous pollutants while capturing oil mist particles. Changes in airflow temperature can cause pollutants to transform from a gaseous state to a liquid state.

[0020] This invention, by sequentially configuring an oil mist interceptor, an electrostatic filter, a gas mixing device, a demister, and a precision filter, ensures that pollutants in the airflow are treated in suitable forms at different stages. Specifically, the oil mist interceptor prioritizes the removal of large-diameter oil mist droplets from the airflow, making the particle size distribution of the oil mist entering the electrostatic filter more suitable for the electrostatic capture process; the electrostatic filter further removes fine oil mist droplets, while simultaneously generating solid particles and gaseous pollutants; the gas mixing device lowers the airflow temperature, causing gaseous oily substances to condense into droplets; the demister separates the formed droplets; and the precision filter removes solid particles from the airflow. Through this processing flow, pollutants of different forms can be effectively removed in suitable treatment units, thereby improving overall purification efficiency.

[0021] By matching the functions of each processing unit, the equipment can operate under suitable working conditions. This invention, through the rational configuration of the processing objects and working environments of each processing unit, enables different devices to function effectively under appropriate conditions. For example, the oil mist interceptor prioritizes intercepting large-diameter oil mist droplets and reduces the oil mist concentration, making the particle size distribution of the oil mist entering the electrostatic filter more suitable for the electrostatic capture process; the gas mixing device works in conjunction with the demister to ensure that condensable substances are condensed and separated before entering subsequent filtration units, thereby preventing liquid substances from entering the precision filter; the precision filter is mainly used to remove solid particles from the airflow, thereby reducing clogging problems caused by liquid substances entering the filter. Through the above structural design, each processing unit can operate under suitable working conditions, thereby improving the system's operational stability.

[0022] The invention optimizes the fan position and airflow organization. The fan is positioned between the demister and the precision filter, ensuring that components with low air resistance, such as the oil mist interceptor, electrostatic filter, gas mixing device, and demister, are all located in the negative pressure zone created at the fan's front end. This prevents excessive pressure drop from affecting the suction force within the CNC equipment. Furthermore, the negative pressure operation at the front end ensures that the oil mist gas is always under suction after entering the system, reducing leakage at equipment connections. Simultaneously, the high-resistance precision filter is placed in the positive pressure zone at the fan's rear end, operating in positive pressure mode to precisely filter solid particles in the airflow under stable airflow conditions. Since pollutants in the airflow in contact with the fan are primarily in the form of solid particles, their impact on fan operation is minimal.

[0023] This invention enables the formation of a compact, independent oil mist purification device. The oil mist purification system of this invention can be housed within a casing to form an independent oil mist purification unit. It connects to the CNC machine tool via a main airflow inlet, introduces cold air through a cold air inlet, and discharges the treated gas through an exhaust vent. This allows the oil mist purification device to be installed near the machine tool for on-site treatment of oil mist gas. Through this structural design, effective purification of oil mist gas is achieved while maintaining a compact structure, making it suitable for small-scale purification applications such as machine tool oil mist treatment.

[0024] Therefore, this invention introduces an airflow cooling and condensation treatment mechanism into a small oil mist purification system. Through comprehensive design of the oil mist treatment process, pollutant morphology changes, and working conditions of each treatment unit, different forms of pollutants can be effectively removed in suitable treatment units, thereby significantly improving the oil mist purification effect and reducing white smoke in the exhaust.

[0025] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0026] Figure 1 This is a perspective view of the oil mist purification device of the present invention; Figure 2 This is a schematic diagram of the internal structure of the oil mist purification device of the present invention, i.e., the oil mist purification system; Figure 3 This is an exploded view of an oil mist interceptor. Figure 4 yes Figure 3 A 3D view of the intercepting turntable; Figure 5 This is a cross-sectional view of the oil mist interceptor.

[0027] Explanation of reference numerals in the attached figures 1-Oil mist interceptor; 1a-House, 1b-Interception turntable, 1b1-Mounting shaft, 1b2-Interception spokes, 1b3-Outer ring frame, 1b4-Guide groove, 1b5-Guide hole, 1c-Drive motor, 1d-Oil drain port; 2-Electrostatic filter; 3-Gas mixing device; 4- Demister; 5- Fan; 6-Precision filter; 7- Coarse filter; 8-Multi-leaf control valve; 9-Air filter; 10-Outer shell. Detailed Implementation

[0028] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0029] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the orientation in the assembled and used state. "Inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself.

[0030] Oil mist purification system Reference Appendix Figure 1 , 2 This invention provides an oil mist purification system for treating oil mist exhaust gas from CNC machine tools. This system is used to purify the oil mist exhaust gas generated during high-speed cutting, grinding, and other machining processes of CNC machine tools, thereby reducing the emission of oil mist pollutants.

[0031] The oil mist purification system, arranged sequentially according to the airflow direction, includes an oil mist interceptor 1, an electrostatic filter 2, a gas mixing device 3, a demister 4, a fan 5, and a precision filter 6. A coarse filter 7 is installed between the electrostatic filter 2 and the gas mixing device 3 to pre-treat the solid particles discharged from the electrostatic filter 2. The gas mixing device 3 has a main airflow inlet and a cold air inlet. A multi-leaf regulating valve 8 and a coarse air filter 7 are installed at the cold air inlet to regulate the flow rate of cold air entering the system and filter dust particles from the outside air.

[0032] Oil mist exhaust from the CNC machine tool forms the main airflow, which first enters the oil mist purification system and then enters the oil mist interceptor 1. The oil mist interceptor 1 is used to initially intercept large-diameter oil mist droplets in the airflow, and at the same time, it changes the particle size distribution of the oil mist droplets through a rotating structure to reduce the proportion of large-diameter oil droplets in the airflow and reduce the load on subsequent processing equipment.

[0033] The main airflow then enters the electrostatic filter 2. The electrostatic filter 2 uses a high-voltage electric field to adsorb and capture fine oil mist particles in the airflow, thereby further reducing the oil mist content in the airflow. During operation, the electrostatic filter 2 generates corona discharge. While capturing oil mist particles, some oil mist particles may decompose or carbonize, thus forming a small amount of solid particles and some gaseous decomposition products.

[0034] After being treated by the electrostatic filter 2, the airflow passes through the coarse filter 7 and then enters the gas mixing device 3. The gas mixing device 3 mixes the main airflow with cooler ambient air, lowering the overall temperature of the airflow and causing some gaseous pollutants to condense, thus converting some gaseous substances into liquid droplets. The gas mixing device 3 introduces workshop air or air conditioning cool air through a cold air inlet, and regulates the airflow entering the gas mixing device 3 via a multi-leaf regulating valve 8, thereby controlling the temperature of the mixed airflow.

[0035] After being mixed and partially condensed in the gas mixing device 3, the airflow enters the demister 4. The demister 4 is used to separate liquid droplets in the airflow, thereby removing the liquid substances generated by condensation from the airflow and reducing the amount of liquid entering subsequent equipment.

[0036] A fan 5 is installed after the demister 4. The fan 5 provides airflow power for the entire oil mist purification system. In this embodiment, the fan 5 is located in the middle of the oil mist purification system, so that a negative pressure working area is formed at the front end of the fan 5 and a positive pressure working area is formed at the rear end of the fan 5. This arrangement enables a stable suction negative pressure to be formed inside the machine tool, while reducing the amount of oil mist contaminants entering the fan 5.

[0037] The airflow processed by demister 4 is drawn in by fan 5 and pressurized before being delivered to precision filter 6 at the back end of the system. Precision filter 6 is used to precisely filter fine solid particles in the airflow, thereby reducing white smoke in the exhaust. Precision filter 6 can use high-efficiency air filter 9 for solid particulate matter filtration. In applications with high environmental protection requirements, an activated carbon filter can also be installed after precision filter 6 to further adsorb gaseous organic matter in the airflow.

[0038] Through the above structural arrangement, the oil mist exhaust gas flows through the oil mist purification system, sequentially passing through the oil mist interceptor 1, electrostatic filter 2, gas mixing device 3, demister 4, fan 5, and precision filter 6, thereby achieving staged treatment of liquid oil mist, solid particles, and some gaseous pollutants in the airflow. In this embodiment, the oil mist purification system not only filters pollutants step-by-step in its structural design but also fully considers the morphological changes of pollutants during treatment. For example, the oil mist interceptor 1 alters the particle size distribution of the oil mist droplets; the electrostatic filter 2 may generate solid particles and gaseous decomposition products during the treatment of oil mist particles; and the gas mixing device 3 reduces the airflow temperature to induce condensation of some gaseous substances, thus creating conditions for subsequent demisting and filtration. Through the synergistic effect of the above multi-stage treatment units, each treatment device can operate under suitable working conditions, thereby improving the purification efficiency and operational stability of the entire oil mist purification system.

[0039] Oil mist interceptor 1 Reference Appendix Figure 3-5 The main airflow from the CNC machine tool first enters the oil mist interceptor 1. The oil mist interceptor 1 is used to pre-treat large-diameter oil mist droplets in the airflow. By intercepting and separating large oil droplets, the concentration of oil mist in the airflow is reduced, and the particle size distribution of the oil mist droplets is changed, thereby creating conditions for the efficient operation of the subsequent electrostatic filter 2.

[0040] The oil mist interceptor 1 is installed inside the airflow channel and mainly includes an interception turntable 1b and a drive motor 1c. The interception turntable 1b includes a mounting shaft 1b1, interception spokes 1b2, and an outer ring frame 1b3. The mounting shaft 1b1 is positioned along the central axis of the airflow channel and connected to the output shaft of the drive motor 1c, rotating under the drive of the drive motor 1c. Multiple interception spokes 1b2 extend radially outward along the mounting shaft 1b1. The inner ends of the interception spokes 1b2 are fixed to the mounting shaft 1b1, and the outer ends are connected to the outer ring frame 1b3, arranged radially in the circumferential direction.

[0041] When the main airflow passes through the intercepting turntable 1b area, the intercepting turntable 1b rotates at high speed under the action of the drive motor 1c. During the movement of the airflow, oil mist droplets collide with the intercepting spokes 1b2. After the collision, the larger oil mist droplets adhere to the surface of the intercepting spokes 1b2 and move outward along the spokes under the action of the centrifugal force generated by the rotation of the intercepting turntable 1b, thus converging at the position of the outer ring frame 1b3.

[0042] An annular guide groove 1b4 is provided on the inner ring surface of the outer ring frame 1b3 to collect oily liquid flowing along the interceptor spokes 1b2. When the oil enters the guide groove 1b4, it is thrown out through the guide hole 1b5 provided on the outer ring frame 1b3 onto the inner wall of the surrounding air duct, and then flows along the inner wall of the air duct under the action of gravity to the bottom of the equipment for centralized discharge.

[0043] While intercepting oil mist droplets, the high-speed rotating intercepting spokes 1b2 also break up some of the oil mist droplets, further refining them and reducing the proportion of large-diameter oil mist particles in the airflow, thus making the particle size distribution of oil mist particles in the airflow more uniform.

[0044] Compared to traditional oil mist pretreatment devices that use metal mesh or baffle structures, the rotary oil mist interceptor 1 in this embodiment has lower airflow resistance and is more suitable for airflow processing systems under negative pressure suction conditions. In the oil mist purification system of this embodiment, the fan 5 is located in the middle of the system, and its front end is the negative pressure working area. Therefore, the air resistance of each processing unit at the front end has a significant impact on the system's suction capacity. By adopting a rotary interception structure, large oil mist particles can be effectively intercepted while reducing airflow resistance, thereby ensuring that the system can form a stable suction negative pressure inside the CNC machine tool.

[0045] Furthermore, since the oil mist interceptor 1 discharges the captured oil through centrifugal force, it has a certain self-cleaning ability. The oil adhering to the interceptor spokes 1b2 can be continuously flung out under the action of centrifugal force, thereby reducing the long-term accumulation of oil on the equipment surface.

[0046] By pre-treating the oil mist interceptor 1, the oil mist concentration in the main airflow is reduced, thus lessening the processing load on the subsequent electrostatic filter 2. On the other hand, it reduces the entry of large-diameter oil mist droplets into the electrostatic filter 2, thereby preventing the efficiency of the electrostatic filter 2 from decreasing when dealing with large droplets that it is not good at handling, and further improving the overall processing effect of the oil mist purification system.

[0047] Electrostatic filter 2 In this embodiment, the main airflow enters the electrostatic filter 2 after being processed by the oil mist interceptor 1. The electrostatic filter 2 is used to further capture fine oil mist droplets in the airflow, thereby reducing the oil mist content in the airflow.

[0048] In the oil mist exhaust gas generated by CNC machine tools, the oil mist droplets typically have a wide particle size distribution. Larger droplets are effectively separated in the front-end oil mist interceptor 1, while the remaining oil mist particles are smaller and usually remain in a mist-like suspended state. For these fine oil mist particles, traditional methods relying on mechanical interception or filter cartridges often require high-density filter materials for effective capture, leading to a significant increase in airflow resistance. Furthermore, the filter cartridges are easily clogged with oil and require frequent replacement.

[0049] In contrast, the electrostatic filter 2 utilizes a high-voltage electric field to charge and capture oil mist particles in the airflow. It has a high processing efficiency for fine oil mist particles and low airflow resistance, thus it is widely used in the field of industrial oil mist purification. Especially in negative pressure suction oil mist treatment systems, the low-resistance electrostatic filter 2 is more conducive to maintaining stable system operation.

[0050] In this embodiment, the electrostatic filter 2 includes a two-stage structure, namely a first electrostatic filter 2 and a second electrostatic filter 2. The first electrostatic filter 2 adopts a wide-spacing electrode structure and operates under high voltage conditions to perform primary collection of oil mist particles in the airflow. A strong electric field is generated by the high voltage, which rapidly charges the oil mist particles in the airflow and adsorbs them onto the surface of the dust collection electrode, thereby achieving coarse filtration.

[0051] The second electrostatic filter 2 is positioned after the first electrostatic filter 2. Its electrode spacing is relatively small, and it operates under constant voltage conditions. The smaller electrode spacing creates a more stable electric field structure, which is used to further capture residual fine oil mist particles in the airflow, thereby improving the overall purification efficiency.

[0052] After being processed by two-stage electrostatic filters, the oil mist droplets in the main airflow can be removed more effectively, resulting in a significant reduction in the liquid oil mist content in the airflow.

[0053] It should be noted that during the operation of the electrostatic filter 2, due to the high-voltage corona discharge phenomenon between the electrodes, when oil mist particles are captured in the electric field or pass through the ionization region, some oil mist particles may undergo cracking, oxidation, or carbonization reactions in the plasma environment, thereby generating a certain amount of solid particulate matter. At the same time, some oil mist droplets may undergo chemical changes before being captured, forming gaseous decomposition products with a certain odor.

[0054] Therefore, after being processed by the electrostatic filter 2, the composition of pollutants in the airflow will change to some extent. In addition to air, it may also contain a small amount of solid particulate matter and some gaseous hydrocarbons. In view of this characteristic, in the oil mist purification system of this embodiment, a gas mixing device 3 and a demister 4 are subsequently set up to further treat the pollutants generated or transformed during the purification process, thereby improving the purification effect of the entire system.

[0055] Furthermore, in this embodiment, a coarse filter 7 is also provided between the electrostatic filter 2 and the gas mixing device 3 for preliminary filtration of the solid particles discharged from the electrostatic filter 2. Since the gas mixing device 3 introduces additional air during operation, increasing the overall airflow, filtration can be completed under lower airflow conditions by removing some of the solid particles before the main airflow mixes with the cold air, thereby improving filtration efficiency and reducing the processing burden on subsequent equipment.

[0056] Gas mixing device 3 In this embodiment, the main airflow enters the gas mixing device 3 after being treated by the electrostatic filter 2. The gas mixing device 3 is used to mix the main airflow with the ambient air at a lower temperature. By reducing the overall temperature of the airflow, some gaseous substances in the airflow condense, thereby changing the physical form of pollutants in the airflow and creating conditions for subsequent treatment.

[0057] During CNC machining, the temperature of the oil mist exhaust gas emitted from the machine tool is typically around 50°C due to the high temperature in the cutting zone, and may even exceed 70°C under some heavy-duty machining conditions. At these temperatures, some hydrocarbons exist in gaseous form in the airflow. These gaseous pollutants are difficult to remove directly through conventional mechanical separation or particle filtration methods; therefore, traditional oil mist treatment systems usually rely on activated carbon adsorption devices. However, activated carbon adsorption devices require periodic replacement of the adsorption material, resulting in high operating costs.

[0058] To address the above situation, this embodiment incorporates a gas mixing device 3 to mix the high-temperature main airflow with cooler air, thereby reducing the overall temperature of the airflow. As the airflow temperature decreases, some of the originally gaseous hydrocarbons condense and form tiny droplets. Through this process, some gaseous pollutants can be converted into liquid pollutants, allowing them to be removed by a subsequent gas-liquid separation device.

[0059] Structurally, the gas mixing device 3 can adopt a mixer or air mixing section structure, which has two gas inlets: a main airflow inlet and a cold air inlet. The main airflow inlet is connected to the outlet of the electrostatic filter 2 and is used to introduce the main airflow after electrostatic filtration; the cold air inlet is used to introduce outside air or cold air provided by the air conditioning system.

[0060] In terms of specific structural form, the gas mixing device 3 can adopt various structural forms capable of achieving airflow mixing. For example, a mixing section structure can be used, where branch air inlets are set on the side wall of the duct, allowing outside cold air and the main airflow to converge and gradually mix within the mixing section; a T-shaped or Y-shaped mixing structure can also be used, allowing airflows from different directions to form turbulent mixing at the convergence point; guide vanes or turbulence structures can also be set inside the mixing channel to enhance the mixing effect between airflows. In some embodiments, a static mixer structure with static mixing elements can also be used, allowing the two airflows to split and recombine when passing through the mixing elements, thereby achieving more thorough mixing.

[0061] To regulate the flow rate of cold air entering the gas mixing device 3, a multi-leaf regulating valve 8 is installed at the cold air inlet. By changing the opening angle of the multi-leaf regulating valve 8, the air resistance of the airflow channel can be changed, thereby regulating the flow rate of air entering the gas mixing device 3 and controlling the temperature of the mixed airflow.

[0062] In addition, an air coarse filter 7 is installed at the cold air inlet to pre-filter the air entering the system, remove dust particles from the air, and prevent external dust from entering the oil mist purification system and increasing the system load.

[0063] When the main airflow and the cold air converge inside the gas mixing device 3, the two airflows mix thoroughly in the mixing section, thus forming a mixed airflow with a lower temperature. During the process of airflow temperature reduction, some gaseous hydrocarbons condense and form droplets, causing a certain number of liquid particles to reappear in the mixed airflow.

[0064] The gas mixing device 3 not only reduces the airflow temperature but also causes some gaseous pollutants to condense prematurely, thus altering the form of the pollutants in the airflow. Subsequently, the demister 4 located at its rear end separates the condensed droplets from the airflow, thereby reducing the content of gaseous pollutants in the airflow and lowering the processing pressure on subsequent filtration equipment.

[0065] Demister 4 In this embodiment, the airflow enters the demister 4 after passing through the gas mixing device 3. The demister 4 is used to separate liquid droplets in the airflow to remove liquid substances that condense due to temperature reduction during the gas mixing process.

[0066] As mentioned earlier, in the gas mixing device 3, after the high-temperature main gas flow mixes with the lower-temperature air, the gas flow temperature decreases, and some of the hydrocarbons that were originally in a gaseous state will condense and form droplets. In addition, the gas flow may still contain a small amount of oil mist droplets that have not been completely captured by the electrostatic filter 2. If these liquid substances directly enter subsequent equipment, they are likely to adhere to the surface of the equipment, thereby affecting the normal operation of the equipment.

[0067] Therefore, a demister 4 is installed after the gas mixing device 3 to separate liquid droplets in the gas flow through a gas-liquid separation structure, thereby reducing the amount of liquid substances entering subsequent equipment.

[0068] Structurally, the demister 4 can adopt a common gas-liquid separation structure, such as a baffle structure, a wire mesh structure, or other demister structures that can capture droplets. When the airflow passes through the demister 4, the airflow direction changes or passes through a separation structure with a certain surface area. The droplets are captured and aggregated into larger droplets under inertial collision or adhesion, and then flow downward along the inner wall of the device under the action of gravity and are discharged.

[0069] The demister 4 effectively separates condensed droplets and residual oil mist droplets from the airflow, thereby reducing the entry of liquid contaminants into downstream equipment. In this embodiment, the demister 4 is installed before the fan 5. Therefore, removing liquid substances through the demister 4 reduces the possibility of liquid adhering to the impeller surface of the fan 5, thereby reducing the impact of oil contamination on the operating performance of the fan 5 and improving the stability of system operation.

[0070] Fan 5 In this embodiment, a fan 5 is installed after the demister 4 to provide airflow power for the entire oil mist purification system, so that the oil mist exhaust gas generated in the CNC machine tool can be continuously extracted and transported to the subsequent processing unit.

[0071] The fan 5 is positioned in the middle of the oil mist purification system, creating a negative pressure working area in front of the fan 5 and a positive pressure working area behind it. This arrangement causes the oil mist exhaust from the CNC machine tool to pass sequentially through the oil mist interceptor 1, electrostatic filter 2, gas mixing device 3, and demister 4 under negative pressure. The exhaust is then drawn in and pressurized at the fan 5 before being transported to the precision filter 6 at the rear, thus completing the entire purification process.

[0072] In the existing technology, there are usually two typical arrangements of the fan 5 in the oil mist treatment system.

[0073] A common approach is to place the fan 5 at the very front of the system, directly connecting its air inlet to the CNC machine tool to create a strong negative pressure inside the machine tool. Various filtration devices are then connected sequentially behind the fan 5. This structure allows for easy creation of a strong suction capacity within the machine tool, and because the filtration system operates under positive pressure, it is less sensitive to air resistance, resulting in a relatively simple system design.

[0074] However, in this structure, the fan 5 comes into direct contact with untreated oil mist exhaust gas. The airflow contains a high concentration of oil mist droplets and solid particles, which easily form stubborn deposits of oil and dust on the impeller surface of the fan 5. These deposits alter the aerodynamic characteristics of the impeller, reduce the operating efficiency of the fan 5, and in severe cases, may cause impeller imbalance, thereby affecting the normal operation of the fan 5 motor and shortening the service life of the equipment.

[0075] Another common approach is to place the fan 5 at the end of the entire filtration system, so that all purification equipment is located in front of the fan 5 and operates under negative pressure. The advantage of this structure is that the gas that the fan 5 comes into contact with has already been purified, and the oil mist content in the gas is low, thereby reducing the impact of oil on the fan 5.

[0076] However, in this structure, the entire filtration system operates under negative pressure, making it highly sensitive to airflow resistance. When the filtration system contains numerous high-resistance components, the pressure drop of the airflow within the system increases significantly, thereby reducing the ability of the fan 5 to generate negative pressure inside the machine tool. To maintain sufficient suction capacity, a higher-powered or larger-sized fan 5 is typically required, increasing system cost and energy consumption.

[0077] To address the aforementioned issues, this embodiment employs a centrally located fan 5, placing the fan 5 in the middle of the oil mist purification system. Specifically, an oil mist interceptor 1, an electrostatic filter 2, a gas mixing device 3, and a demister 4 are sequentially arranged in front of the fan 5. These devices exhibit low overall airflow resistance, enabling stable operation under negative pressure conditions and ensuring a stable suction negative pressure within the CNC machine tool.

[0078] Meanwhile, after multi-stage front-end treatment, the oil mist droplet content in the airflow entering the fan 5 has been significantly reduced, and liquid pollutants have been largely removed after treatment by the demister 4, resulting in the air entering the fan 5 mainly consisting of air and a small amount of solid particles. This gas environment has minimal impact on the impeller of the fan 5, thereby reducing oil deposition on the impeller.

[0079] A precision filter 6 is installed behind the fan 5 to put this part of the equipment into a positive pressure operating state. Since airflow can overcome greater resistance under positive pressure, a precision filter with higher airflow resistance but higher filtration efficiency can be installed at this location to further improve the purification effect of the system.

[0080] Through the above structural design, the fan 5 can avoid direct contact with high-concentration oil mist gas, ensure that the system can form sufficient suction capacity inside the CNC machine tool, and provide a stable positive pressure airflow for the downstream precision filtration equipment, thereby improving the reliability of system operation while ensuring the purification effect.

[0081] Precision Filter 6 In this embodiment, a precision filter 6 is installed after the fan 5 to further filter fine solid particles in the airflow, thereby improving the cleanliness of the exhaust and reducing white smoke in the exhaust.

[0082] As mentioned earlier, after the main airflow passes through the oil mist interceptor 1 and the electrostatic filter 2, most of the oil mist droplets have been removed. Under the corona discharge of the electrostatic filter 2, some oil mist particles may decompose or carbonize, thus forming a certain number of solid particles. In addition, in the gas mixing device 3, by reducing the airflow temperature, some gaseous substances condense and form droplets, which are then separated and removed in the demister 4. After the above treatment, the airflow entering the fan 5 mainly contains air and a small amount of solid particles, and may also contain a very small amount of droplets that have not been completely removed and uncondensed gaseous substances.

[0083] The fan 5 pressurizes the airflow and delivers it to the precision filter 6. The precision filter 6 is used to finely filter the fine solid particles in the airflow, thereby removing suspended particles and reducing white smoke in the exhaust.

[0084] In terms of specific structure, the precision filter 6 can be a high-efficiency air filter 9, such as a HEPA high-efficiency air filter 9. This type of filter can efficiently capture fine particulate matter in the airflow, thereby significantly reducing the particulate matter content in the exhaust. In some embodiments, if the emission requirements for gaseous pollutants are high, an activated carbon filter can be further installed after the precision filter 6, or an activated carbon filter can be directly used to adsorb gaseous organic matter in the airflow.

[0085] Unlike the front-end processing unit, the precision filter 6 is located after the fan 5, and therefore operates in a positive pressure zone. Since the airflow has already been pressurized by the fan 5, even though the precision filter 6 has high airflow resistance, it will not significantly affect the suction negative pressure formed inside the CNC machine tool, thus enabling the use of high-efficiency precision filtration equipment while ensuring stable system operation.

[0086] Furthermore, since most of the liquid oil mist has been removed by devices such as the oil mist interceptor 1, the electrostatic filter 2, and the demister 4 before entering the precision filter 6, the liquid content in the airflow entering the precision filter 6 is low. This can prevent droplets from accumulating on the filter material and causing blockage, thereby increasing the service life of the precision filter 6 and reducing the maintenance frequency.

[0087] System operating mechanism In this embodiment, the oil mist purification system not only removes pollutants from the airflow step by step through multiple processing units, but also fully considers the morphological changes of pollutants during the purification process in the system design. Through the cooperation between different processing units, various pollutants are effectively treated at appropriate stages.

[0088] The main airflow from the CNC machine tool first enters the oil mist interceptor 1. The oil mist interceptor 1 uses high-speed rotating interception spokes 1b2 to collide with oil mist droplets in the airflow, thereby intercepting and separating large-diameter oil mist droplets. During this process, large-diameter oil mist droplets are captured and ejected from the airflow under centrifugal force, while some droplets are broken up during the collision, further refining the particle size distribution. This process reduces both the oil mist concentration in the main airflow and the proportion of large-diameter oil mist droplets in the airflow, making the remaining oil mist particles more suitable for subsequent treatment by the electrostatic filter 2.

[0089] After being processed by the oil mist interceptor 1, the main airflow enters the electrostatic filter 2. The electrostatic filter 2 uses a high-voltage electric field to charge the oil mist particles, which are then adsorbed onto the surface of the dust collection electrode under the influence of the electric field, thereby further removing oil mist droplets from the airflow. During the operation of the electrostatic filter 2, due to the presence of corona discharge, some oil mist particles may undergo decomposition, oxidation, or carbonization reactions, forming a certain amount of solid particles, and may also generate a small amount of gaseous decomposition products. Therefore, after treatment by the electrostatic filter 2, the composition of pollutants in the airflow will change to some extent, and in addition to air, it may also contain a small amount of solid particles and some gaseous hydrocarbons.

[0090] The main airflow then enters the gas mixing device 3. Since the oil mist exhaust gas from CNC machine tools is typically at a high temperature, cooler air is introduced into the gas mixing device 3 to mix with the main airflow, thus lowering the overall temperature of the airflow. As the airflow temperature decreases, some of the originally gaseous hydrocarbons condense and form droplets. Through this process, some gaseous pollutants are converted into liquid pollutants, allowing them to be removed by subsequent gas-liquid separation devices.

[0091] A demister 4 is installed after the gas mixing device 3. The demister 4 uses a gas-liquid separation structure to capture and separate liquid droplets in the gas flow, thereby removing liquid substances condensed during gas mixing and residual oil mist droplets. This step significantly reduces the content of liquid pollutants in the gas flow, making the airflow environment entering the fan 5 more stable.

[0092] The airflow then enters fan 5. Fan 5 provides airflow power for the entire system, creating a stable suction negative pressure inside the CNC machine tool, while simultaneously pressurizing and delivering the airflow to the downstream processing unit. Because the airflow has undergone multi-stage treatment before entering fan 5, the liquid oil mist has been largely removed. Therefore, the airflow entering fan 5 mainly contains air and a small amount of solid particles, thereby reducing oil deposition on the impeller surface of fan 5.

[0093] Finally, the airflow enters the precision filter 6. The precision filter 6 uses high-efficiency filter material to capture fine solid particles in the airflow, thereby further reducing the particulate matter content and minimizing white smoke in the exhaust. After treatment by the precision filter 6, the concentration of pollutants in the airflow is significantly reduced, ultimately resulting in cleaner exhaust gas.

[0094] Through the above processing steps, the oil mist purification system can adopt corresponding treatment methods for pollutants in different forms in the airflow, effectively removing liquid oil mist, solid particles, and some gaseous pollutants at different stages. Simultaneously, by rationally setting the sequence of each treatment unit, the morphological changes of pollutants during treatment can be further processed by subsequent equipment, thereby improving the overall purification efficiency and operational stability of the system.

[0095] Oil mist purification equipment Reference Appendix Figure 1 In this embodiment, the aforementioned oil mist purification system can be integrated into a single unit structure, thereby forming an oil mist purification device for treating oil mist exhaust gas from CNC machine tools. This oil mist purification device can be installed as a standalone unit near the CNC machine tool and connected to the air extraction port on the machine tool housing 10 via a pipe for centralized treatment of oil mist exhaust gas generated during machine tool processing.

[0096] Structurally, the oil mist purification equipment includes a housing 10 and an oil mist purification system installed inside the housing 10. An airflow channel is formed inside the housing 10 for sequentially installing processing units such as an oil mist interceptor 1, an electrostatic filter 2, a gas mixing device 3, a demister 4, a fan 5, and a precision filter 6, with each processing unit arranged sequentially according to the airflow direction.

[0097] The equipment housing 10 is equipped with a main airflow inlet, a cold air inlet, and an exhaust vent. The main airflow inlet is used to connect to the exhaust pipe of the CNC machine tool to introduce the oil mist exhaust gas generated inside the machine tool; the cold air inlet is used to supply outside air or air conditioning cool air to the gas mixing device 3; the exhaust vent is used to discharge the purified gas, or the precision filter 6 can be directly installed at the exhaust vent.

[0098] Inside the equipment, each processing unit is installed in the airflow channel in a predetermined order, so that the oil mist exhaust gas entering the equipment passes through the oil mist interceptor 1, electrostatic filter 2, gas mixing device 3, demister 4, fan 5 and precision filter 6 in sequence under the action of airflow, thereby completing the entire purification process.

[0099] Furthermore, in the equipment structural design, inspection doors or removable panels can be installed on the equipment casing 10 as needed to facilitate the maintenance, replacement, or cleaning of the internal processing units. For example, the electrostatic filter 2 can be cleaned periodically, and the precision filter 6 can be replaced, thereby ensuring the long-term stable operation of the equipment.

[0100] By integrating the aforementioned oil mist purification systems into a single integrated oil mist purification device, each processing unit can work collaboratively within a unified structural framework. This not only reduces equipment installation space but also simplifies system piping connections, improving the overall structural compactness and operational stability. Furthermore, this oil mist purification device allows for the selection of different specifications based on the exhaust volume requirements of various CNC machine tools, thus adapting to the oil mist exhaust gas treatment needs under different processing conditions.

[0101] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Furthermore, the present invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. An oil mist purification system, characterized in that, It includes an oil mist interceptor (1), an electrostatic filter (2), a gas mixing device (3), a demister (4), a fan (5), and a precision filter (6) arranged sequentially along the airflow direction; The oil mist interceptor (1) is used to intercept large-diameter oil mist droplets in oil mist gas; The electrostatic filter (2) is used to remove oil mist droplets from the oil mist gas; The gas mixing device (3) has a main airflow inlet and a cold air inlet, which is used to mix the main airflow after it has been treated by the electrostatic filter (2) with the cold air to reduce the airflow temperature and condense the gaseous pollutants. The demister (4) is used to remove droplets formed after the gas mixture condenses; The fan (5) is positioned between the demister (4) and the precision filter (6), so that the oil mist interceptor (1), the electrostatic filter (2), the gas mixing device (3) and the demister (4) are in the negative pressure zone at the front end of the fan (5), and the precision filter (6) is in the positive pressure zone at the rear end of the fan (5). The precision filter (6) is used to remove solid particles from the airflow.

2. The oil mist purification system according to claim 1, characterized in that, The oil mist interceptor (1) includes a housing (1a), an interception turntable (1b) disposed inside the housing (1a), and a drive motor (1c) for driving the interception turntable (1b) to rotate. An airflow channel for oil mist gas is formed inside the housing (1a). An air inlet and an air outlet are respectively provided at both ends of the airflow channel. When the oil mist gas passes through the rotating intercepting disc (1b), it collides with the intercepting disc (1b), so that large-diameter droplets in the oil mist are captured and separated from the airflow.

3. The oil mist purification system according to claim 2, characterized in that, The intercepting turntable (1b) includes a mounting shaft (1b1), multiple radially distributed intercepting spokes (1b2), and an outer ring frame (1b3). The inner ends of the intercepting spokes (1b2) are fixed on the mounting shaft (1b1), and the outer ends are connected to the outer ring frame (1b3). A guide groove (1b4) extending circumferentially is opened on the inner edge of the outer ring frame (1b3). The guide groove (1b4) is provided with multiple guide holes (1b5) communicating with the outer side of the outer ring frame (1b3), so that the oil stains attached to the intercepting spokes (1b2) flow outward along the intercepting spokes (1b2) to the guide groove (1b4) under the centrifugal force generated by the rotation of the intercepting turntable (1b) and are thrown out to the inner wall of the housing (1a) through the guide holes (1b5). The bottom of the shell (1a) forms an oil storage tank and is provided with an oil drain (1d) so that the oil sludge collects along the inner wall of the shell (1a) into the oil storage tank and is then discharged. The drive motor (1c) is positioned on the side of the intercepting turntable (1b) near the air outlet to reduce the deposition of oil on the drive motor (1c).

4. The oil mist purification system according to claim 1, characterized in that, The electrostatic filter (2) includes a first electrostatic filter (2) for primary coarse filtration and a second electrostatic filter (2) for secondary fine filtration. The electrode spacing of the first electrostatic filter (2) is greater than that of the second electrostatic filter (2), and the operating voltage of the first electrostatic filter (2) is greater than that of the second electrostatic filter (2).

5. The oil mist purification system according to claim 1, characterized in that, A coarse filter (7) is provided between the electrostatic filter (2) and the gas mixing device (3) to remove solid particles from the airflow.

6. The oil mist purification system according to claim 1, characterized in that, The gas mixing device (3) includes a main airflow inlet and a cold air inlet. The main airflow inlet is connected to the electrostatic filter (2), and the cold air inlet is used to introduce workshop air or air conditioning cold air to reduce the temperature of the main airflow and promote the condensation of some gaseous substances into droplets.

7. The oil mist purification system according to claim 6, characterized in that, A multi-leaf regulating valve (8) is provided at the cold air inlet to regulate the flow rate of cold air entering the gas mixing device (3), thereby controlling the temperature of the mixed airflow. An air filter (9) is also provided at the cold air inlet to remove dust particles from the cold air entering the gas mixing device (3).

8. The oil mist purification system according to claim 1, characterized in that, The precision filter (6) is a high-efficiency air filter (9) used to precisely filter solid particles in the airflow to eliminate white smoke in the exhaust.

9. The oil mist purification system according to claim 1, characterized in that, The precision filter (6) is an activated carbon filter, or an activated carbon filter is provided downstream of the precision filter (6) to adsorb gaseous organic matter in the airflow.

10. An oil mist purification device, characterized in that, Includes a housing (10) and an oil mist purification system as described in any one of claims 1 to 9 disposed within the housing (10); The outer casing (10) of the device is provided with a main airflow inlet for connecting to the CNC machine tool, a cold air inlet for introducing cold air, and an exhaust port, so that the oil mist purification device can be installed as an independent device next to the CNC machine tool and treat the oil mist gas discharged from the machine tool.

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