Machining workshop oil mist centralized discharge system, control system and control method

Abstract

The invention relates to the field of industrial workshop pollution gas exhaust systems, in particular to a machining workshop oil mist centralized exhaust system, a control system and a control method. In order to solve the problem that open-type processing equipment is difficult to be directly connected into a centralized exhaust system, the exhaust and treatment system comprises a gas collecting hood, an induced draft fan and an air pressure buffer device. The air pressure buffering device effectively reduces static pressure and preliminarily separates oil mist through an internal corrugated partition plate and a turbulent flow structure. The control system collects data through static pressure and flow velocity sensors, calculates target static pressure through a controller, outputs control signals, dynamically adjusts the rotating speed of the induced draft fan, achieves self-adaptive control under different working conditions, and ensures safe operation of the system.

Description

Technical Field

[0001] The present invention relates to the field of machining oil mist treatment and purification, and in particular to a centralized oil mist exhaust system, a control system and a control method for a machining workshop. Background Art

[0002] Mechanical processes such as cutting, painting, and stretch forming often involve the use of oily substances such as lubricants and coolants. These substances are easily atomized during high-speed rotation, spraying, or impact, mixing with air to form oil mist. If this oil mist is not promptly and effectively treated, it will diffuse into the workshop air, polluting the environment, endangering the health of operators, and increasing safety risks such as fire.

[0003] To control oil mist pollution in workshops, some modern machining plants generally use centralized exhaust systems to collect and centrally treat oil mist emissions from multiple processing equipment. These systems typically consist of a main fan, a main air duct, several branch ducts, and an oil mist filter. The main fan creates negative pressure within the main duct, driving the branch ducts to draw oil mist generated within enclosed equipment (such as CNC machine tools) into the ducts. The system then transports the oil mist to the final treatment unit for purification and discharge.

[0004] However, in addition to enclosed processing equipment, many machining centers also feature a variety of open processing equipment, such as large lathes, stamping machines, and welding tables. Due to the open structure, large size, and scattered distribution of oil mist sources, this type of equipment tends to diffuse rapidly around the equipment, making it difficult to efficiently collect it through closed extraction methods.

[0005] Existing centralized exhaust systems are difficult to directly apply to open processing equipment. If branch ducts are drawn from the main air duct to connect to open equipment, the original system air volume is distributed to multiple devices, and the actual air extraction capacity of each device is limited, which cannot meet the high air volume extraction requirements of open equipment. Furthermore, open equipment lacks a sealed structure. If the air extraction port is improperly set, it may lead to uneven pressure distribution in the system, disrupting the original wind pressure gradient and affecting the operational stability of the entire exhaust system.

[0006] In summary, when facing open processing equipment, the existing centralized exhaust system has problems such as difficulty in adaptation, insufficient air volume, and low oil mist collection efficiency, making it difficult to achieve unified and efficient oil mist control goals. Summary of the Invention

[0007] In response to the above-mentioned deficiencies or defects in the prior art, the present invention provides a centralized oil mist exhaust system for a machining workshop. The system can be applied to open equipment, integrating the oil pollution collection and treatment of the open equipment with the original centralized exhaust system in the workshop, and utilizing the air ducts and post-processing equipment of the centralized exhaust system to reduce the system complexity and operating costs.

[0008] Specifically, the centralized oil mist exhaust system of the machining workshop includes: Centralized exhaust system, including a main fan, a main air duct, a plurality of branch air ducts connected to the main air duct, and an oil mist filtering treatment device connected to the outlet of the main air duct; The gas collection hood is installed next to the oil mist release area of ​​the open processing equipment to collect the oil mist gas; an induced draft fan, the inlet of which is connected to the air collecting hood; The wind pressure buffer device has an inlet connected to the air outlet of the induced draft fan and an outlet connected to the main air duct through the induced draft duct. The wind pressure buffer device can reduce the static pressure of the gas to alleviate the air flow impact at the connection with the main air duct.

[0009] In some embodiments, the wind pressure buffer device includes a shell, and a plurality of corrugated partitions are arranged in the shell. The partitions are arranged parallel to each other, and the gaps between the partitions form a tortuous airflow channel with multiple turns.

[0010] In some embodiments, the corrugated partition extends vertically, the bottom of the shell is provided with an oil collecting trough, and the bottom of the oil collecting trough is provided with an oil drain port for draining oil.

[0011] In some embodiments, the corrugated partition is provided with a flow-disturbing structure to enhance airflow disturbance. The flow-disturbing structure provided at the corner of the partition includes a protrusion structure and / or a corrugated spoiler.

[0012] In some embodiments, a filter assembly is further provided in the wind pressure buffer device, and the filter assembly is provided in the air flow channel between the corrugated partition and the outlet of the wind pressure buffer device.

[0013] In some embodiments, the gas collecting hood has a flow guide structure, and the gas collecting hood has a collecting port with an adjustable angle.

[0014] The present invention also proposes a control system for the centralized oil mist exhaust system in the machining workshop, the control system comprising: A first static pressure sensor provided at the outlet of the wind pressure buffer device; A second static pressure sensor is provided at the connection section between the main air duct and the induced air duct of the centralized exhaust system; A controller connected to the two static pressure sensor signals, used to obtain the static pressure difference between the buffer device outlet and the main air duct; A frequency converter for controlling the working state of the induced draft fan; The controller compares the pressure difference between the detection values ​​of the first static pressure sensor and the second static pressure sensor with a preset target pressure difference value, and outputs a control signal to the frequency converter to adjust the speed of the induced draft fan.

[0015] In some embodiments, the control system further comprises a flow velocity sensor disposed in the induced draft duct, the flow velocity sensor being connected to the controller signal and its output wind velocity data being recorded as v; The controller combines the wind speed data v and the output data of the first static pressure sensor , the second static pressure sensor output data Calculate the expected static pressure target value at the outlet of the wind pressure buffer device , whose expression is: Controller Comparison and Based on the difference, the speed of the induced draft fan is adjusted to make ; in, is the comprehensive pressure drop of the induced draft duct section, is the adjustment margin term, k is the air pressure compensation coefficient; L is the length of the induced draft pipe, D is the equivalent diameter of the induced draft pipe, is the density of oil mist gas, f is the friction resistance coefficient, and ξ is the local resistance coefficient.

[0016] The present invention also proposes a control method applied to the control system, comprising the following steps: S1, real-time data collection, the first static pressure sensor collects the current static pressure at the outlet of the buffer device ; The second static pressure sensor obtains the static pressure of the main air duct section ; The flow rate sensor provides the instantaneous gas velocity in the induced draft duct ; S2, calculate the target static pressure expected value , in, is the comprehensive pressure drop of the induced draft duct section, is the adjustment margin term, k is the air pressure compensation coefficient, L is the length of the induced draft duct, D is the equivalent diameter of the induced draft duct, is the density of oil mist gas, f is the friction resistance coefficient, ξ is the local resistance coefficient; S3, deviation judgment, the actual static pressure and target static pressure Perform difference operation to generate error signal e; S4, output control signal, controller calculates control quantity ; in: For time, is the proportionality coefficient, is the integration time constant, is the differential time constant; S5, execute control, the inverter receives the control signal , adjust the induced draft fan speed.

[0017] The present invention further proposes a storage medium, which is used to store algorithm data. When the algorithm data is executed by the controller, it is used to implement the control method described above.

[0018] The application of the above technical solution of the present invention to a centralized oil mist exhaust system, control system, control method and storage medium for a machining workshop has the following effects.

[0019] Logical discussion of technical solutions: In machining workshops, open equipment (such as open CNC machine tools, large lathes, and stamping machines) lacks a sealed cavity, making it difficult to efficiently collect the oil mist generated. Therefore, a high-flow exhaust system is required to prevent the oil mist from dispersing.

[0020] However, the centralized exhaust system can only allocate a limited amount of airflow to each branch duct. Therefore, it is necessary to install independent induced draft fans at open equipment to increase airflow. However, when the airflow from the induced draft fans at open equipment is directly connected to the main air duct, the following problems may arise: 1) Disruption of the main duct pressure gradient: Directly connecting to multiple open equipment air outlets disrupts the air flow distribution and static pressure gradient inside the main duct, causing a decrease in the efficiency of the entire centralized system and even affecting the ventilation effect of some equipment.

[0021] 2) Backflow risk: When the pressure in the main air duct is higher than that at the outlet of the induced draft system, gas backflow will occur, that is, high-pressure gas containing oil mist will flow back into the CNC processing area, polluting the working environment and interfering with production safety.

[0022] Due to these issues, current technologies for open equipment typically employ localized exhaust methods, either directly discharging the oil mist generated by the equipment or installing independent oil mist filtration devices. However, these solutions are not only costly and difficult to maintain, but also prone to energy waste and excessive emissions.

[0023] The present invention provides a wind pressure buffer device after the induced draft fan, while providing a large suction flow rate for an independent induced draft fan in an open-type equipment. The induced draft fan airflow passes through the buffer device and is then introduced into the main air duct of the centralized exhaust system, which has the following advantages: 1) Safe access to the centralized exhaust system: By installing a wind pressure buffer device, the static pressure at the induced air outlet is effectively reduced, solving the problem of gas backflow and ensuring the safety of airflow between open equipment and the main air duct; 2) Reduce system interference: The buffer device has pressure coordination and stabilization functions to avoid pressure disturbances in the main air duct system caused by the simultaneous connection of multiple induced air ducts; 3) Strong structural versatility: This solution does not rely on centralized system modification, making it easy to quickly deploy and promote in existing main air duct systems; 4) The renovation and operation costs are low. The existing centralized exhaust system’s branch pipe system can be used to introduce the oil mist generated by the open equipment into the post-processing equipment of the centralized exhaust system, eliminating the need to set up an independent filtration system.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the overall principle diagram of the centralized oil mist exhaust system for machining workshops of the present invention; Figure 2 yes Figure 1 Schematic diagram of the connection from the open processing equipment to the main air duct; Figure 3 It is a schematic diagram of the corrugated partition in the wind pressure buffer device.

[0026] 1-Centralized exhaust system, 1a-Main fan, 1b-Main air duct, 1c-Branch air duct, 1d-Oil filtration and treatment equipment; 2-Gas collection hood; 3- induced draft fan; 4-wind pressure buffer device, 4a-corrugated partition, 4b-disturbing structure, 4c-flow channel; 5- induced draft duct; 6-First static pressure sensor; 7- Second static pressure sensor; 8-Flow rate sensor; 9-Open processing equipment. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] The present invention provides a unified oil mist emission and treatment system suitable for mechanical processing workshops. To address the problem that open processing equipment 9 cannot be effectively connected to a centralized system, the invention provides an induced draft fan 3, an air pressure buffer device 4 and an intelligent control system to achieve stable and safe oil mist collection and treatment.

[0030] The centralized exhaust system 1, an existing or pre-installed system in the factory, comprises a main fan 1a, a main air duct 1b, and multiple branch ducts 1c connecting the main duct 1b to the enclosed processing equipment. The outlet of the main air duct 1b is connected to an oil mist filtration treatment device, centrally treating the oil mist gas discharged from multiple devices.

[0031] The main fan 1a, the power source of the centralized exhaust system 1, is typically located at the outlet of the main air duct 1b. Its continuous operation creates a stable negative pressure zone within the main air duct 1b, driving the oil mist in the branch air ducts 1c and even the exhaust system toward the oil mist filtration equipment, achieving unified extraction at multiple locations.

[0032] The main air duct 1b is the primary airflow channel for the entire centralized exhaust system 1, connecting the main fan 1a with the branch ducts 1c and ultimately delivering air to the oil mist filtration equipment. The main air duct 1b is a negative pressure duct. The static pressure decreases closer to the main fan 1a within the main air duct 1b, forming a pressure gradient that gradually increases from the main fan 1a to the end. This ensures that airflow within the main air duct 1b always flows toward the main fan 1a. The static pressure within the main air duct 1b typically ranges from approximately -200 Pa to -1500 Pa.

[0033] The branch air duct 1c is used to connect the main air duct 1b with each independent closed processing equipment (mainly CNC machine tools with sealed cabins) to achieve branch drainage of oil mist gas.

[0034] The oil mist filtration equipment, connected to the outlet of the main air duct 1b, is used to purify residual oil mist particles and oil vapor components in the workshop exhaust air, preventing them from being directly discharged into the environment and causing pollution. The oil mist filtration equipment has a multi-stage filtration structure, including mechanical separation, electrostatic adsorption, spray washing, and activated carbon adsorption.

[0035] The present invention adds an air induction system for the open processing equipment 9 without changing the structure of the centralized exhaust system 1, so that it can be safely connected to the main air duct 1b. Figure 2 As shown, the induced air system includes an air collecting hood 2, a wind pressure buffer device 4 and an induced air duct 5.

[0036] The gas collecting hood 2 is arranged above or to the side of the oil mist dissipation area of ​​the open processing equipment 9, and is used to capture the oil mist gas released during the operation of the equipment in the first time to prevent it from spreading to the working environment.

[0037] The main body of the hood is made of metal or corrosion-resistant engineering plastic. The hood 2 adopts a partially enclosed design. It is a semi-enclosed collection chamber with a bell-shaped structure that partially covers the oil mist release area. The hood opening faces the oil mist release area, and a certain negative pressure is maintained inside to induce airflow into the hood and guide it to the collection port. From there, it is delivered to the main exhaust system through the induced draft system.

[0038] Baffles or guide grooves are installed inside or on the edges of the hood to optimize airflow distribution within the hood opening, reduce turbulent areas and eddy current blind spots, and thus improve the efficiency of collecting oil mist entering the hood. The gas collection hood 2 features adjustable air inlets or baffles to accommodate different workpiece types and equipment configurations. The hood is equipped with removable panels for easy maintenance and cleaning.

[0039] The hood 2 is mounted and fixed by a movable robotic arm, and its opening direction and height can be adjusted as needed. For example, when machining large parts, the hood can be moved upward; during precision machining, the hood can be lowered closer to the workstation to enhance local suction efficiency.

[0040] The induced draft fan 3 is the primary power component for extracting the open-type oil mist. It is responsible for extracting the oil mist collected from the open-type processing equipment 9 and conveying it to the main exhaust system. The induced draft fan 3 provides a stable negative pressure for the hood 2, extracting the captured oil mist away from the release source and providing sufficient dynamic pressure to ensure a smooth transition of the mist through the wind pressure buffer device 4 to the main air duct 1b system.

[0041] The induced draft fan 3 is a power unit installed between the outlet of the air collecting hood 2 and the wind pressure buffer device 4. Its inlet end is connected to the air collecting hood 2 and is used to actively suck the oil mist gas released by the open equipment; its outlet is connected to the wind pressure buffer device 4 to form an independent drainage path to transport the oil mist to the centralized exhaust system 1.

[0042] The induced draft fan 3 uses a speed-regulating fan, which needs to support variable frequency control or be able to work in conjunction with the control system to achieve dynamic adjustment of wind pressure.

[0043] The wind pressure buffer device 4 is a key component for safely connecting open equipment to the centralized exhaust system 1. It performs the triple functions of reducing static pressure, performing preliminary oil mist filtration, and buffering airflow pulsation. It is positioned between the outlet of the induced draft fan 3 and the main air duct 1b. Its inlet is connected to the outlet of the induced draft fan 3, and its outlet is connected to the main air duct 1b via the induced draft duct 5. The wind pressure buffer device 4 can be constructed as a box-type or cylindrical enclosed cavity, comprising an outer shell, several sets of corrugated baffles, a filter screen, and an oil discharge structure.

[0044] The housing is a pressure-resistant, sealed structure with air inlets and outlets at both ends, creating an expanded cavity in the middle to accommodate other equipment. The housing is constructed from corrosion-resistant materials (stainless steel, weathering steel, aluminum alloy, galvanized steel), and the interior surface can be optionally coated with an oleophobic coating to reduce oil contamination.

[0045] like Figure 3 As shown, the baffles are corrugated plates, arranged in groups perpendicular to the plate surface, with a spacing of 20-50 mm between the baffles. The gaps between the baffles form a narrow, undulating, and tortuous flow channel 4c. The oil mist airflow experiences significant resistance as it passes through flow channel 4c, reducing static pressure.

[0046] As the oil mist flows through flow channel 4c, oil droplets have a chance of striking the baffle surfaces and being captured, thereby reducing the oil content in the mist. The baffles are vertically oriented, and the corrugations extend in a vertical direction. The captured oil can flow downward along the corrugations.

[0047] The corrugated partition is made of corrosion-resistant metal material, and the surface of the corrugated partition 4a is coated with an oleophilic and hydrophobic coating to enhance the adhesion and aggregation ability of oil mist droplets on the partition surface, and promote the captured oil droplets to flow along the partition corrugation direction to the oil collecting tank, thereby improving the separation efficiency and reducing sludge accumulation.

[0048] The flow-disrupting structure 4b is designed to further enhance the pressure reduction and oil-collecting effectiveness of the wind pressure buffer 4. It is incorporated into the corrugated baffle to increase airflow disturbance within the flow channel 4c. The corrugated baffle can be designed with serrated edges or perforated flow-disrupting holes at its bends. Alternatively, vortex rings or rotating guide vanes can be incorporated into the flow channel 4c to create localized vortex disturbances, further enhancing the collision capture efficiency of oil droplets.

[0049] The oil collection tank is located at the bottom of the housing, directly below the corrugated partition, and has a "V"-shaped or flat-bottomed oil collection structure. A drain port is provided at the bottom of the oil collection tank and connected to a hose to the waste oil collection area. The oil collection tank can be equipped with a transparent liquid level observation window or high and low liquid level alarm sensors.

[0050] The filter assembly is arranged in front of the air outlet end of the wind pressure buffer device 4, and the filter assembly is installed with a metal mesh and / or a high-efficiency fiber filter element to further capture the remaining oil and dirt fine particles.

[0051] After entering the wind pressure buffer device 4, the oil mist is dispersed into the flow channel 4c formed by the gaps between the corrugated baffles. This tortuous channel generates multiple airflow turns and localized acceleration zones, creating high-frequency disturbances. A flow disturbance structure 4b is incorporated within flow channel 4c to maintain a subturbulent or turbulent flow state within the flow channel 4c. The separated airflow passes through the terminal filter assembly, forming a relatively stable low-pressure and constant-velocity airflow, which smoothly transitions into the main air duct 1b.

[0052] The main air duct 1b is typically installed on the workshop roof, while the induced draft fan 3 and wind pressure buffer device 4 need to be installed on the workshop floor. Therefore, an induced draft duct 5 is installed to connect the outlet of the wind pressure buffer device 4 and the main air duct 1b. The induced draft duct 5 is preferably made of oil-resistant and temperature-resistant metal or composite pipe, with an inner diameter that matches the air volume to ensure smooth airflow.

[0053] In order to prevent pressure leakage in the main air duct 1b when the induced draft fan 3 is not running, a pneumatic or electric control valve is provided on the induced draft duct 5, which can be automatically opened or closed according to the operating status of the induced draft fan 3.

[0054] The present invention also provides a control system for a centralized oil mist exhaust system in a machining workshop. This system dynamically coordinates the static pressure relationship between the wind pressure buffer device 4 and the centralized exhaust system 1, ensuring that the oil mist flow from open equipment can be stably connected to the main air duct 1b while preventing problems such as backflow or abnormal flow rate caused by pressure mismatch.

[0055] The control system includes the following hardware devices: a first static pressure sensor 6, a second static pressure sensor 7, a flow rate sensor 8, a controller and a frequency converter.

[0056] The first static pressure sensor 6 is set at the outlet of the wind pressure buffer device 4, which is used to monitor the static pressure value of the outlet of the induced air system (i.e. the outlet of the buffer device) in real time and output it to the controller as .

[0057] The second static pressure sensor 7 is set in the main air duct 1b, located at the connection section between the main air duct 1b and the induced air duct 5 of the induced air system. It is used to monitor the local static pressure value of the main air duct 1b and output it to the controller as .

[0058] The flow rate sensor 8 is arranged in the induced draft pipe 5 to measure the flow rate of the oil mist gas in the induced draft pipe 5 and output it to the controller as v. A thermal mass flow meter, a pitot tube or a micro differential pressure tube can be used.

[0059] The controller collects and integrates the signals of the first static pressure sensor 6, the second static pressure sensor 7, and the flow rate sensor 8, and outputs the results to the frequency converter to control the speed of the induced draft fan 3. The controller can be a PLC or an embedded MCU.

[0060] The frequency converter drives the induced draft fan 3 to rotate, and can also receive control signals from the controller to change the power and speed of the induced draft fan 3.

[0061] The controller combines the wind speed data v and the output data of the first static pressure sensor 6 , the second static pressure sensor 7 outputs data , calculate the expected static pressure target value at the outlet of wind pressure buffer device 4 . The expression is: Controller Comparison and Based on the difference, the speed of the induced draft fan 3 is adjusted to make .in, is the comprehensive pressure drop of the 5 sections of the induced draft duct, is the adjustment margin term, k is the air pressure compensation coefficient; L is the length of the induced draft pipe 5, D is the equivalent diameter of the induced draft pipe 5, is the density of oil mist gas, f is the friction resistance coefficient, and ξ is the local resistance coefficient.

[0062] In conjunction with the above control system, the present invention also proposes a control method that operates in the above control system. The control method includes: S1, real-time data collection, the first static pressure sensor 6 collects the current static pressure at the outlet of the buffer device The second static pressure sensor 7 obtains the static pressure of the main air duct 1b ; Flow rate sensor 8 provides the instantaneous gas velocity in the induced draft tube 5 .

[0063] S2, calculate the target static pressure expected value ; in, is the comprehensive pressure drop of the 5 sections of the induced draft duct, is the adjustment margin term, k is the air pressure compensation coefficient, L is the length of the induced draft pipe 5, D is the equivalent diameter of the induced draft pipe 5, is the density of oil mist gas, f is the friction resistance coefficient, and ξ is the local resistance coefficient.

[0064] The margin term is used to compensate for uncalculated and unpredictable disturbances. k is the pressure compensation coefficient, which can be positive or negative and is typically set to 0.1-0.4. A more accurate value can be obtained through experimentation or fluid simulation analysis.

[0065] S3, deviation judgment, the actual static pressure and target static pressure Perform difference operation to generate error signal e; S4, output control, re-input the error signal e into the control module and output the control quantity ; in, For time, is the proportionality coefficient, is the integration time constant, is the differential time constant.

[0066] S5, execution control, the inverter according to Adjust the speed of induced draft fan 3.

[0067] The controller periodically samples pressure and flow rate feedback signals and outputs control signals. The frequency converter adjusts the speed of the induced draft fan 3 based on these control signals. When pressure fluctuations or load changes in the main duct 1b system are detected, the induced draft system responds accordingly to maintain dynamic balance.

[0068] The above control system and control method can dynamically match the wind pressure of the main air duct 1b and automatically track the static pressure changes of the main air duct 1b without manual intervention, and will not cause backflow due to changes in the load of the main air duct 1b.

[0069] In order to implement the above control algorithm, the present invention further provides a storage medium for storing the above control method operation program. When the controller runs the operation program of the above control algorithm, the operation program is read and executed by the controller.

[0070] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0071] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0072] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A centralized oil mist exhaust system for a machining workshop, characterized in that: include: A centralized exhaust system (1) includes a main fan (1a), a main air duct (1b), a plurality of branch air ducts (1c) respectively connected to the main air duct (1b), and an oil mist filtering treatment device connected to an outlet of the main air duct (1b); A gas collecting hood (2) is provided next to the oil mist release area of ​​the open processing equipment (9) and is used to collect the oil mist gas; An induced draft fan (3), the inlet of which is connected to the air collecting hood (2); The wind pressure buffer device (4) has an inlet connected to the air outlet of the induced draft fan (3), and an outlet connected to the main air duct (1b) through an induced draft duct (5). The wind pressure buffer device (4) can reduce the static pressure of the gas.

2. The centralized oil mist exhaust system for machining workshops according to claim 1, characterized in that: The wind pressure buffer device (4) comprises an outer shell, wherein a plurality of corrugated partitions (4a) are arranged in the outer shell, the partitions are arranged parallel to each other, and the gaps between the partitions form a tortuous flow channel (4c).

3. The centralized oil mist exhaust system for machining workshops according to claim 2, characterized in that: The corrugated partition (4a) extends vertically, and the bottom of the shell is provided with an oil collecting groove, and the bottom of the oil collecting groove is provided with an oil drain port for draining oil.

4. The centralized oil mist exhaust system for machining workshops according to claim 2, characterized in that: The corrugated partition (4a) is provided with a flow disturbance structure (4b) to enhance airflow disturbance.

5. The centralized oil mist exhaust system for machining workshops according to claim 2, characterized in that: A filter assembly is also provided in the wind pressure buffer device (4), and the filter assembly is provided in the air flow channel between the corrugated partition plate (4a) and the outlet of the wind pressure buffer device (4).

6. The centralized oil mist exhaust system for machining workshops according to claim 1, characterized in that: The gas collecting hood (2) has a flow guide structure, and the gas collecting hood (2) is provided with a collecting port with an adjustable angle.

7. A control system for a centralized oil mist exhaust system in a machining workshop according to any one of claims 1 to 6, characterized in that: include: A first static pressure sensor (6) provided at the outlet of the wind pressure buffer device (4); A second static pressure sensor (7) is provided at a connection section between a main air duct (1b) and an induced draft duct (5) of a centralized exhaust system (1); A controller connected to the two static pressure sensor signals, used to obtain the static pressure difference between the outlet of the buffer device and the main air duct (1b); A frequency converter for controlling the working state of the induced draft fan (3); The controller compares the pressure difference between the detection values ​​of the first static pressure sensor (6) and the second static pressure sensor (7) with a preset target pressure difference value, and outputs a control signal to the frequency converter to adjust the speed of the induced draft fan (3).

8. The control system according to claim 7, characterized in that: The control system further comprises a flow velocity sensor (8) arranged in the induced air duct (5), the flow velocity sensor (8) being connected to the controller signal, and the output wind velocity data thereof being recorded as v; The controller combines the wind speed data v and the output data of the first static pressure sensor (6) , the second static pressure sensor (7) output data Calculate the expected static pressure target value at the outlet of the wind pressure buffer device (4) , whose expression is: Controller Comparison and Based on the difference, the speed of the induced draft fan (3) is adjusted to make ; in, is the comprehensive pressure drop of the induced draft duct (5), is the adjustment margin term, k is the air pressure compensation coefficient; L is the length of the induced draft pipe (5), D is the equivalent diameter of the induced draft pipe (5), is the oil mist gas density, f is the friction resistance coefficient, and ξ is the local resistance coefficient.

9. A control method applied to the control system according to claim 8, characterized in that: The control method comprises the following steps: S1, real-time data collection, the first static pressure sensor (6) collects the current static pressure at the outlet of the buffer device The second static pressure sensor (7) obtains the static pressure of the main air duct (1b) ; The flow rate sensor (8) provides the instantaneous gas velocity in the induced draft tube (5) ; S2, calculate the target static pressure expected value , in, is the comprehensive pressure drop of the induced draft duct (5), is the adjustment margin term, k is the air pressure compensation coefficient, L is the length of the induced draft duct (5), D is the equivalent diameter of the induced draft duct (5), is the density of oil mist gas, f is the friction resistance coefficient, ξ is the local resistance coefficient; S3, deviation judgment, the actual static pressure and target static pressure Perform difference operation to generate error signal e; S4, output control signal, controller calculates control quantity ; in: For time, is the proportionality coefficient, is the integration time constant, is the differential time constant; S5, execute control, the inverter receives the control signal , adjust the speed of the induced draft fan (3).

10. A storage medium, characterized in that: The storage medium is used to store algorithm data, and when the algorithm data is executed by the controller, it is used to implement the control method described in claim 9.

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