What Is an Air Filter?
Before we dive into how are air filters manufactured, let’s touch on what air filters are and what they are used for. Air filters are devices with porous material that remove airborne particulates such as dust, pollen, bacteria, smog, and odors from the air. Air filters are used in HVAC systems to purify the air and prevent contaminants from settling in the system. Different types of raw materials and machines are used in the manufacturing of air filters.
Types of Air Filter Media
The filtering components responsible for capturing the contaminants in the air are known as filter media. Different types of filter media are used in air filters, with the most commonly used material being perforated mesh or synthetic fibers. Filter media is classified into two types, non-pleated and pleated.
Non-pleated air filters are made of electrostatic or fiberglass materials and typically require frequent replacement and maintenance. On the other hand, pleated air filters have a larger filtration area due to the number of folds. These filters are made from materials such as cotton, cloth, paper, or polyester. Although they are effective in capturing microscopic particles, they may restrict airflow due to the material density.
High-quality air filters include high-efficiency particulate absorbing (HEPA) filters that can remove fine particles from the air. The MERV rating of the air filter is used as an indicator of the efficiency of the filter in removing pollutants from the air. High-quality air filters have a rating of 8 or higher.
Raw Materials and Manufacturing Process
The manufacturing process of air filters starts by gathering raw materials. According to FilterKing, the type of raw materials used in air filter manufacturing depends on the type of air filter that is being manufactured. The most common raw materials include cold-rolled close annealed (CRCA) sheets.
Components for the top and bottom rims include zinc, plastic, and aluminum. Fasteners, polyurethane foam or PU foam, non-woven fabric, filter paper, and enclosures are also used as raw materials for air filter manufacturing. The grade of the filter paper depends on the application. Most parameters considered while choosing the filter grades include the wet strength, particle retention, and volumetric flow rate of the material.
The machines required for the manufacturing process depend on the type of air filter. Typically, a marking machine or a rotary pleating machine is used to piece the filters together. Other machines used in the manufacturing process include tube rolling, pleat cutting, leak and pressure testing, CAV coiling, air filter testing, and Hot Plate for End Cap Curing machines.
During manufacturing, the power press perforates and cuts the steel sheets. Then the fitment holes are drilled on the die bottoms and tops. To get the desired type of filter, winding, pleating, or corrugation is performed. Finally, the filter element is assembled with top and bottom holding units. After the air filter is manufactured, it undergoes inspection and testing. Filters that do not meet manufacturing standards are scraped or recycled.
Filters for Specific Purposes
In recent times, there has been a growing awareness of the importance of maintaining good indoor air quality due to escalating concerns about air pollution. Air filtration emerges as a critical aspect in achieving this objective, acting as the first line of defense against airborne contaminants. Air filters come in various types, each designed to target specific pollutants and deliver effective purification.
HEPA (High-Efficiency Particulate Air) filters have gained a reputation for their exceptional efficiency in removing microscopic particles from the air. Dust, pollen, pet dander, and other allergens are captured with remarkable precision, making HEPA filters invaluable for individuals with allergies or asthma. These filters are capable of trapping particles as small as 0.3 microns with an efficiency of 99.97%, ensuring that the air circulating in indoor spaces is remarkably clean and free from respiratory irritants.
When it comes to tackling odors and volatile organic compounds (VOCs), air filters incorporating activated carbon are the go-to choice. Activated carbon possesses a unique ability to adsorb and neutralize gases and chemicals, effectively eliminating unpleasant odors and enhancing the overall freshness of the air. This makes activated carbon filters particularly beneficial in areas with strong odors or spaces where chemical off-gassing is a concern.
For those seeking a balance between improved indoor air quality and energy efficiency, pleated filters made with synthetic filter material are highly recommended. These filters feature a pleated design, which significantly increases the surface area for filtration. The synthetic filter material used provides excellent dust-holding capacity and enhances the filter’s overall lifespan. By striking a balance between filtration efficiency and airflow resistance, pleated filters offer optimal air purification while minimizing the strain on HVAC systems, leading to energy savings.
Air Filter Ratings
When selecting an air filter, it is crucial to assess its filter efficiency. Filter efficiency determines how effectively a filter captures pollutants of varying sizes. It is often indicated by a MERV (Minimum Efficiency Reporting Value) rating, which ranges from 1 to 20. A higher MERV rating signifies greater filtration efficiency, as the filter can trap smaller particles. However, it is important to consider the compatibility of the filter with the HVAC system to ensure proper airflow.
Air Filter Maintenance
Regular maintenance and replacement of air filters are of paramount importance. Dirty air filters can become clogged with trapped particles, hindering airflow and diminishing their ability to capture pollutants effectively. In fact, neglected filters can become a source of indoor air pollution themselves, as accumulated contaminants may be released back into the air. Therefore, adhering to a schedule of routine filter replacement is essential for maintaining optimal indoor air quality and ensuring the longevity of HVAC systems. We discuss in our article here how not maintaining your air filter can affect your HVAC unit.
By carefully choosing the right air filter tailored to specific needs—whether it’s HEPA filters for allergen control, activated carbon filters for odor removal, or pleated filters for a balance of performance and energy efficiency—individuals can significantly enhance indoor air quality. Prioritizing clean air promotes a healthier living environment, reduces the risk of respiratory issues, and contributes to overall well-being.
FAQ About Air Filters
Q. What is an air filter?
A. An air filter is a device designed to remove contaminants from the air before it enters a particular space, such as a room, building or vehicle. It is typically made of a filter media that can capture and hold particulate matter.
Q. What are the benefits of using an air filter?
A. Using an air filter can provide many benefits, such as improving indoor air quality, reducing air pollution, protecting HVAC systems from damage caused by clogged filters and reducing the amount of contaminants in the air which can lead to health problems.
How do air filters work?
A. Air filters work by forcing the air through a filter material, which captures and holds particulate matter and other contaminants in the air. Depending on the type of filter, they may rely on an electrostatic charge, mechanical filtration, or a combination of both to capture the contaminants. In general, HEPA filters are the most effective type of filter for capturing very small particles.
What are pleated air filters?
A. Pleated air filters are a type of air filter that are composed of a series of pleats that increase the filter’s surface area, allowing it to capture more contaminants without reducing airflow. They are often used in HVAC systems to improve air quality and reduce the frequency of filter changes.
Why do air filters need to be changed?
A. Air filters need to be changed regularly because over time, they can become clogged with captured contaminants and reduce airflow. Dirty air filters can cause HVAC systems to work harder, leading to higher energy bills and potentially damaging the system.
What is MERV?
A. MERV stands for Minimum Efficiency Reporting Value, which is a numerical rating system used to rate the efficiency of air filters. The higher the MERV rating, the more efficient the filter is at capturing small particles.
Q. Can I see an air filter being made?
A. Check out this video showing the air filter-making process.