In industrial painting workshops, coating quality, production safety, and employee health are core concerns. Air cleanliness critically affects coating outcomes by influencing defect rates. Pleated high-efficiency filters, known for high filtration efficiency and structural stability, have become essential in air purification for these workshops, supporting stable coating processes and ensuring product quality.
I. Core Demands for Air Purification in Industrial Painting Workshops
The industrial coating process (such as painting, drying, pretreatment, etc.) has strict requirements for the air environment, mainly due to the following three demands:
Coating quality assurance requirements: During the coating process, if dust, fibers, metal debris and other particles in the air adhere to the surface of the workpiece to be coated or the coating that has not dried, it will directly cause defects such as pitting, particles and scratches on the coating, seriously affecting the appearance and protective performance of the product, and may even lead to rework or scrapping.
Production safety control requirements: Some coating processes use solvent-based paints, which will release flammable and explosive organic waste gases such as toluene and xylene. Meanwhile, if the paint mist produced during the spraying process accumulates for a long time, it will not only clog the equipment but also pose a potential safety hazard. An efficient air filtration system needs to be combined with exhaust devices to reduce the concentration of harmful substances and avoid the risks of fire and explosion.
Occupational health protection requirements: If the paint mist, organic waste gas and dust in the painting workshop are inhaled by employees for a long time, it will damage the respiratory system, nervous system, etc., which does not meet the requirements of standards such as “Occupational Exposure Limits for Hazardous Factors in Industrial Sites”. Air purification needs to effectively intercept harmful particles and improve the working environment in the workshop.
Given these requirements, the air purification system must intercept fine particles efficiently, operate stably, and handle complex working conditions. High-efficiency filters with separators are well suited to fulfill these demands.
Ii. Core Advantages and Compatibility of High-efficiency Filters with Separators
High-efficiency filters with separators use glass fiber filter paper and aluminum foil or paper partitions to form uniform airflow channels, making them suitable for harsh workshop environments.
Outstanding filtration efficiency According to the GB/T 13554-2020 “High Efficiency Air Filters” standard, its filtration efficiency for 0.3μm particles can reach over 99.97% (H13 grade and above), effectively intercepting paint mist particles, dust and condensed volatile organic compounds (VOCs) in the painting workshop, reducing coating defects from the source.
Stable structure and strong temperature resistance: The aluminum foil partition not only keeps the filter material spacing uniform, ensuring stable air flow through, but also has excellent temperature resistance (some models can withstand high temperatures of 80-120℃), which is suitable for the high-temperature air circulation and purification requirements of the drying process in the painting workshop, avoiding the deformation and failure of the filter due to high temperature.
High dust holding capacity and long service life: Compared with filters without separators, the filter material with a separator structure has a larger spread area, significantly increasing the dust holding capacity (typically up to 150-300g/m²), reducing the downtime caused by frequent filter replacement, lowering operation and maintenance costs, and is suitable for continuous industrial production scenarios.
Good impact resistance: In the painting workshop, there are situations such as air flow fluctuations and equipment vibrations. The rigid structure of the filter with separators can effectively resist air flow impacts, prevent the filter material from shifting or being damaged, and ensure stable filtration performance.
Iii. Specific application Scenarios of High-efficiency filters with Separators in Painting Workshops
The application of high-efficiency filters with separators in painting workshops runs through the entire process of “supply air purification – process purification – exhaust air purification”. The core application scenarios can be divided into the following three categories:
(1) Clean air supply system: Ensuring the cleanliness of the coating environment
The core areas of the painting workshop, such as the spray booth, paint mixing room, and the storage area for pre-treated workpieces, need to maintain a positive pressure clean environment to prevent the intrusion of external polluted air. High-efficiency filters with separators are typically used as the “terminal filtration equipment” in clean supply air systems, installed at the end of the supply air duct or at the air outlet.
Spray booth application: The spray booth is a key area for coating quality control, and the air cleanliness is required to reach ISO 8-7 level. The air supply system first pre-processes the air through a primary filter (intercepting large particles larger than 5μm) and a medium-efficiency filter (intercepting particles 1-5μm), and then deeply filters it through a high-efficiency filter with a separator (H13/H14 grade). The clean air is then sent into the spray booth in a uniform laminar or turbulent flow form to ensure that no impurities adhere to the surface of the workpiece during the spray painting process.
Application in the paint mixing room: During the paint mixing process, paint dust and volatile solvents are produced. A high-efficiency filter with separators, in conjunction with a supply fan, supplies clean air to the paint mixing room to maintain positive pressure, preventing external dust from mixing into the paint. At the same time, the volatile harmful gases are discharged through the exhaust system.
(2) Cyclic purification in the drying process: Enhance the quality and safety of drying
After coating, the workpieces need to enter the drying room for curing treatment. The drying temperature is usually between 60 and 180℃ (adjusted according to the type of coating). If the circulating air contains impurities, they will adhere to the surface of the incompletely cured coating, resulting in defects such as “orange peel” and “pinholes”. Meanwhile, an excessively high concentration of VOCs in the circulating air may pose safety risks.
The high-efficiency filter with separators (selecting heat-resistant aluminum foil separators) is integrated into the air circulation system of the drying room. Before the air is heated by the heater, it first passes through the high-efficiency filter to intercept the paint mist residue and dust particles in the circulating air, ensuring that the hot air entering the drying room is clean. Meanwhile, the filtered clean air can come into more uniform contact with the workpiece, enhancing the drying and curing effect and reducing the color difference of the coating.
(3) Exhaust terminal purification: Reduce pollutant emissions
The exhaust air in the painting workshop (such as the exhaust air from the spray booth and the drying room) contains a large amount of paint mist, VOCs and dust. If directly discharged, it will cause air pollution, and the paint mist particles may clog the exhaust ducts or fans. The high-efficiency filter with separators can be used as a “deep interception device” at the end of the exhaust air, in conjunction with paint mist filters (such as activated carbon filters, wet paint mist purifiers) :
The exhaust air first passes through a wet paint mist purifier to remove most of the paint mist particles, then passes through a high-efficiency filter with separators to intercept the remaining tiny paint mist particles (0.3-1μm) and dust, and finally is discharged after being adsorbed by activated carbon for VOCs, ensuring that the discharged gas meets the requirements of the “Integrated Emission Standard of Air Pollutants” (GB 16297-1996). At the same time, it avoids fine particles from wearing the fan impeller and extends the service life of the equipment.
Iv. Key Points for Selection, Installation and Maintenance of High-Efficiency Filters with Separators
To fully leverage the role of the high-efficiency filter with separators, it is necessary to carry out a full-process management of “selection – installation – maintenance” in combination with the specific working conditions of the painting workshop.
(1) Scientific selection: Match the working conditions and requirements
When selecting the model, the following parameters should be given particular attention:
Filtration efficiency grade: Select based on the cleanliness requirements of the area. It is recommended to choose H13 grade for spray booths and workpiece storage areas. If the temperature in the drying room is relatively high (> 80℃), the heat-resistant type H13 grade should be selected. For exhaust purification, H11-H12 grades can be selected to balance efficiency and cost.
Rated air volume: Calculate the air volume based on the workshop area and the air change rate (for example, the air change rate in a spray booth is usually 10-20 times per hour). Ensure that the rated air volume of the filter matches the system air volume to avoid a decrease in filtration efficiency due to excessive air volume or insufficient air flow due to insufficient air volume.
Temperature resistance: For the drying process, an aluminum foil partition filter with a temperature resistance of ≥100℃ should be selected. For ordinary air supply systems, paper partition filters (with a temperature resistance of ≤60℃) can be selected to reduce costs.
Dimensions and interfaces: Determine the external dimensions of the filter based on the size of the supply/exhaust air duct and the installation space (such as standard specifications like 484×484×220mm, 610×610×292mm, etc.), and match the flange interface type (such as flat flange, insert flange) to ensure a sealed installation.
(2) Standardized installation: Avoid leakage risks
Improper installation can easily lead to “bypass leakage” (unfiltered air entering the clean area through the gap). Please note:
Pre-installation inspection: Before installation, confirm that the filter is undamaged, the filter paper is not shifted, and the spacing of the partitions is uniform. Clean the installation frame and the surrounding area to remove dust and debris.
Sealing treatment: Install sealing strips (such as neoprene rubber, silicone) or apply sealing glue between the filter and the installation frame to ensure a tight fit. When installing, apply pressure evenly to avoid poor sealing in some areas.
Correct airflow direction: Install strictly in accordance with the “Airflow direction” label on the filter (usually “the air inlet side facing the coarse/medium efficiency side”) to avoid reverse airflow causing damage to the filter material or a decrease in efficiency.
(3) Regular maintenance: Ensure stable operation
Differential pressure monitoring: Install differential pressure gauges at the air inlet and outlet of the filter. When the differential pressure exceeds twice the initial differential pressure (usually the initial differential pressure is 100-150Pa), it indicates that the filter material has seriously accumulated dust and needs to be replaced in time to avoid insufficient system air volume due to excessive resistance.
Replacement cycle: The replacement cycle of the filter in a common air supply system is usually 6 to 12 months. It is recommended that severely polluted areas such as drying rooms and spray painting rooms be replaced every 3 to 6 months, with specific adjustments based on the results of pressure difference monitoring.
Replacement specification: When replacing, the system fan must be turned off, and dust-free gloves should be worn to avoid hand contact with the filter material. Old filters should be sealed and packaged and treated as hazardous waste (as they adsorb paint mist and VOCs, they may be classified as hazardous waste). New filters should be installed immediately after opening to avoid exposure and contamination.
V. Application Value: Dual improvement in economic and environmental benefits
The application of high-efficiency filters with separators in painting workshops can bring significant economic and environmental benefits
Enhance product qualification rate: By efficiently intercepting impurities, the defect rate of coatings can be reduced by 30% to 50%, lowering rework costs and enhancing the market competitiveness of products.
Reduce operation and maintenance costs: The features of high dust holding capacity and long service life decrease the frequency of filter replacement, saving 20% to 30% of consumables and downtime maintenance costs annually.
Ensure production safety: Cooperate with the exhaust system to reduce the concentration of VOCs and paint mist, avoid fire risks, and at the same time reduce equipment wear and extend the service life of fans, heaters and other equipment.
Compliance with environmental protection regulations: The terminal exhaust purification can ensure that the particulate matter emission concentration is ≤10mg/m³, meeting environmental protection requirements and avoiding the risk of fines or production suspension due to excessive emissions.
Vi. Summary and Development Trends
The pleated high-efficiency filter, with its high efficiency, stability and durability, has become the core equipment for air purification in industrial coating workshops. Its application is directly related to coating quality, production safety and environmental protection compliance. With the transformation of the coating industry towards “green and intelligent”, high-efficiency filters with separators are also constantly upgrading: on the one hand, filters with special material separators (such as stainless steel separators) that can withstand higher temperatures (such as above 150℃) and corrosion are gradually being applied in high-temperature coating processes; On the other hand, “smart filters” integrated with Internet of Things (iot) technology have begun pilot projects. By using built-in sensors to monitor pressure differences and filter material conditions in real time, they achieve automated maintenance early warning. In the future, high-efficiency filters with separators will continue to play a significant role in adapting to more complex coating conditions and enhancing the level of intelligent operation and maintenance, providing key support for the high-quality development of the industrial coating industry.
