Homeمقالات تخصصیTechnical Review and Quality Metrics of Air Filters in Intake & Ventilation Systems Technical Review and Quality Metrics of Air Filters in Intake & Ventilation Systems 11 November 2025 Abstract The air filter is one of the vital components in internal combustion and HVAC systems. Its main function is to remove suspended particles from the airflow before entering the engine or indoor environment. Optimal performance of this component directly contributes to increased engine efficiency, reduced fuel consumption, improved air quality, and the protection of related parts. This article examines the structure of air filters, the physical operating principles, key technical parameters affecting performance, and the main indicators used to determine filter quality. Furthermore, the characteristics of an ideal air filter are analyzed from technical and international standard perspectives. 1. Introduction The presence of dust, soot, and airborne pollutants is one of the main causes of engine part wear and reduced combustion efficiency. Using an appropriate air filter prevents component abrasion, improves combustion, and reduces emissions. Moreover, in ventilation and air purification systems, a suitable filter enhances environmental health and increases equipment lifespan. Therefore, understanding the technical indicators and performance standards of air filters is of great importance. 2. Structure and Operating Principles of Air Filters Air filters are typically made of multiple layers of porous or fibrous material that capture solid particles and pollutants as air flows through. The operating principle of an air filter is based on several physical mechanisms: 1. Mechanical interception: Larger particles deviate from the airflow path and collide with the filter fibers. 3. Surface accumulation: Particles gradually accumulate on the surface or within the depth of the filter media, eventually increasing pressure drop. These processes act simultaneously, resulting in progressive purification of the air from contaminants. 3. Technical Parameters for Evaluating Air Filters The quality and performance of an air filter are evaluated based on several technical indicators. The most important parameters include: Technical Parameter Description Functional Importance Physical Dimensions Length, width, diameter, thickness, and shape (flat, cylindrical, pleated, etc.) Determines compatibility with the installation system Pressure Drop The filter’s resistance to airflow Directly affects engine power and energy consumption Filtration Efficiency Percentage of particles removed by the filter, usually at a defined particle size The main indicator of filter quality Dust Holding Capacity The amount of contamination the filter can retain before saturation Determines the effective service life of the filter Type and Material of Media Filter material type: cellulose, synthetic fibers, or multilayer composites Affects durability, efficiency, and cost Mechanical Stability Resistance to deformation and airflow pressure Ensures stable performance under harsh conditions Operating Temperature and Humidity Range Environmental conditions under which the filter maintains performance Important for industrial and automotive applications Standards and Quality Certificates Compliance with national standards and automaker testing plans 4. Characteristics of an Ideal Air Filter An efficient air filter must balance two opposing factors: high filtration efficiency and low pressure drop. In summary, an ideal air filter should have the following features: High efficiency in capturing fine particles (over 95% for small particulates) Low pressure drop High dust holding capacity and long service life Resistance to environmental conditions such as heat and humidity Compliance with international performance and safety standards 6. Pleat Design and Optimization One of the most important technical aspects in filter design is the pleating pattern and arrangement of filter layers. When pleats are designed symmetrically, uniformly, and with calculated spacing, the effective filtration area increases while the initial pressure drop decreases. In professional designs, the pleat angle and depth are optimized using airflow simulation software and experimental testing to achieve three main goals: Increase the effective filter area without increasing physical size Prevent pleat sticking or compression under airflow Ensure uniform air distribution across the media and avoid localized contamination This structure ensures stable performance, controlled pressure drop, and higher dust holding capacity throughout the filter’s service life. Therefore, precise pleat design is a key factor distinguishing high-quality industrial filters from standard ones. 7. Design Considerations and Filter Materials The choice of filter media greatly influences final performance. Today, multilayer composites are used, including: Modified cellulose papers, Nanofiber layers to enhance filtration efficiency, Conclusion Air filters play a vital role in protecting engines and air distribution systems against environmental contaminants. The quality of this component affects not only technical performance but also energy consumption, equipment lifespan, and environmental health. Therefore, selecting the right air filter should be based on technical criteria such as efficiency, pressure drop, dust holding capacity, optimized pleat design, and compliance with recognized standards. Ultimately, a high-quality air filter should provide clean air with minimal pressure loss and have a long service life.
Abstract The air filter is one of the vital components in internal combustion and HVAC systems. Its main function is to remove suspended particles from the airflow before entering the engine or indoor environment. Optimal performance of this component directly contributes to increased engine efficiency, reduced fuel consumption, improved air quality, and the protection of related parts. This article examines the structure of air filters, the physical operating principles, key technical parameters affecting performance, and the main indicators used to determine filter quality. Furthermore, the characteristics of an ideal air filter are analyzed from technical and international standard perspectives. 1. Introduction The presence of dust, soot, and airborne pollutants is one of the main causes of engine part wear and reduced combustion efficiency. Using an appropriate air filter prevents component abrasion, improves combustion, and reduces emissions. Moreover, in ventilation and air purification systems, a suitable filter enhances environmental health and increases equipment lifespan. Therefore, understanding the technical indicators and performance standards of air filters is of great importance. 2. Structure and Operating Principles of Air Filters Air filters are typically made of multiple layers of porous or fibrous material that capture solid particles and pollutants as air flows through. The operating principle of an air filter is based on several physical mechanisms: 1. Mechanical interception: Larger particles deviate from the airflow path and collide with the filter fibers. 3. Surface accumulation: Particles gradually accumulate on the surface or within the depth of the filter media, eventually increasing pressure drop. These processes act simultaneously, resulting in progressive purification of the air from contaminants. 3. Technical Parameters for Evaluating Air Filters The quality and performance of an air filter are evaluated based on several technical indicators. The most important parameters include: Technical Parameter Description Functional Importance Physical Dimensions Length, width, diameter, thickness, and shape (flat, cylindrical, pleated, etc.) Determines compatibility with the installation system Pressure Drop The filter’s resistance to airflow Directly affects engine power and energy consumption Filtration Efficiency Percentage of particles removed by the filter, usually at a defined particle size The main indicator of filter quality Dust Holding Capacity The amount of contamination the filter can retain before saturation Determines the effective service life of the filter Type and Material of Media Filter material type: cellulose, synthetic fibers, or multilayer composites Affects durability, efficiency, and cost Mechanical Stability Resistance to deformation and airflow pressure Ensures stable performance under harsh conditions Operating Temperature and Humidity Range Environmental conditions under which the filter maintains performance Important for industrial and automotive applications Standards and Quality Certificates Compliance with national standards and automaker testing plans 4. Characteristics of an Ideal Air Filter An efficient air filter must balance two opposing factors: high filtration efficiency and low pressure drop. In summary, an ideal air filter should have the following features: High efficiency in capturing fine particles (over 95% for small particulates) Low pressure drop High dust holding capacity and long service life Resistance to environmental conditions such as heat and humidity Compliance with international performance and safety standards 6. Pleat Design and Optimization One of the most important technical aspects in filter design is the pleating pattern and arrangement of filter layers. When pleats are designed symmetrically, uniformly, and with calculated spacing, the effective filtration area increases while the initial pressure drop decreases. In professional designs, the pleat angle and depth are optimized using airflow simulation software and experimental testing to achieve three main goals: Increase the effective filter area without increasing physical size Prevent pleat sticking or compression under airflow Ensure uniform air distribution across the media and avoid localized contamination This structure ensures stable performance, controlled pressure drop, and higher dust holding capacity throughout the filter’s service life. Therefore, precise pleat design is a key factor distinguishing high-quality industrial filters from standard ones. 7. Design Considerations and Filter Materials The choice of filter media greatly influences final performance. Today, multilayer composites are used, including: Modified cellulose papers, Nanofiber layers to enhance filtration efficiency, Conclusion Air filters play a vital role in protecting engines and air distribution systems against environmental contaminants. The quality of this component affects not only technical performance but also energy consumption, equipment lifespan, and environmental health. Therefore, selecting the right air filter should be based on technical criteria such as efficiency, pressure drop, dust holding capacity, optimized pleat design, and compliance with recognized standards. Ultimately, a high-quality air filter should provide clean air with minimal pressure loss and have a long service life.