Compressed Air Filters: Construction, Working Principle, and Classification

Compressed air filters are a common and essential device, designed to effectively remove impurities and dirt that may exist in compressed air, helping you have a clean and safe air source. If you are looking for information on how to choose a compressed air filter, please refer to the article below.

What is a compressed air filter?

A compressed air filter is a component that functions to filter pollutants in compressed air when introduced into a compressed air system. The filter can separate oil, remove residues and dirt, and control and regulate air flow. At the same time, it provides lubricating oil to help the system minimize the friction of other moving devices in the compressed air system.

When the compressed air flow continuously increases, if not filtered and separated, impurities will accumulate to form oil sludge, rust, and scale that are harmful to the machinery system. When dirt penetrates deep inside pneumatic controllers, it stagnates at moving parts, causing blockages and breakdowns in the entire system, leading to serious damage.

Depending on each machine equipment and controller, the filter system will be structured with different functions including: air separation, oil separation, water separation,… In today’s market, air filters are widely used with broad coverage in many industries.

The device is manufactured in many different structural forms including: double compressed air filters, single compressed air filters, sealed tanks, air filters with pressure regulators. Depending on the specific working purpose and needs, usage method, and capacity, users can choose the most suitable equipment for their work in life.

Structure of a compressed air filter

A compressed air filtration system has a very simple design. An air filter is designed with 3 main parts: the filter element, the pressure regulator, and the lubricator.

Filter element

This is an important part that directly affects the quality of the output compressed air when passing through the filter unit. The filter element has a structure including: Filter body, cover, and air filter membrane. Naltako will specifically analyze each part.

Filter body part: designed with a tapered section which is an area with condensed vapor along with residue and dust components contained in the compressed air filtered by a mesh layer. This part has a transparent design so you can easily see the residue. A drain port is installed at the bottom to help remove and clean the exhaust air chamber from the filter body to prevent overload.

Cover part: connects with the inlet and outlet of the compressed air. This is the location to install measuring and pressure regulating devices to indicate the compressed air pressure level circulating through the system. This is an important component linking the filter membrane with the compressed air stream.

Air filter membrane part: The most important part that Naltako wants to mention in the system has the effect of preventing residue and stagnant water vapor. Allowing the purest compressed air stream into the surrounding environment. The ability to filter particles with small sizes from 5 μm – 70 μm. The filter plate has 2 separate components that can remove solids or remove condensed water.

Pressure regulator

True to its name. This is a system including a pressure sensor device to check the flow of the compressed air source when flowing through the valve. In addition, on the device, there will be a rotary knob to adjust the pressure so that the compressed air flow at the outlet always maintains at a certain level. Absolutely protecting all equipment during operation, limiting pressure drops and damage to the entire equipment. When the inlet pressure increases too high compared to the set pressure, the compressed air flow increases its effect on the valve surface causing the needle axis to shift, and compressed air goes through the exhaust hole out to the outside environment. Such continuous adjustment happens until the pressure returns to match the initially set pressure, then the needle returns to its original state.

Lubricator part – Oil bowl

This is a part installed together with the control valve and the filter membrane part forming a complete filtration system. The oil bowl works to hold hot oil and pump oil to create a mist helping to cool the compressed air stream.

In addition, the oil will follow the air to help lubricate welds and joints, contributing to minimizing friction, cleaning, and helping to reduce heat. The lubricator part should be continuously controlled and maintained to prolong the life of the oil valve.

Operating principle of a compressed air filter

When equipped with an automated operation valve, compressed air passing through the inline mesh filter will create an accumulation mixture phenomenon. In the first stage, all large-sized particles will be absorbed and kept at the position before the filter mesh. Clean air passing through combined with moisture will go through the mesh towards the blower position.

In the first stage, particles, dirt, and impurities are removed, accounting for about 95% of the total coarse impurities. Coarse impurities will settle at the bottom of the container and accumulate slowly until full. Moving to the second stage, compressed air enters the separation chamber, a spiral fiber filter. Compressed air is mixed, creating friction upon contact with the filter membrane’s surface, generating a static charge to capture small particles in the fiber filter. In the final stage, the compressed air pressure will gradually decrease.

At the outlet position, there will be a pressure gauge and a pressure adjustment screw to help compressed air at the outlet limit the phenomenon of overloading the system’s operating pressure. The valve system design ensures safe equipment operation; when compressed air pressure rises high, the valve will be lifted to push out compressed air flow and rebalance the system. Compressed air will go into the exhaust valve, the lubricating oil/grease stored at the valve will automatically evaporate and form a fine mist, helping compressed air and oil escape out of the air filter and through the pipeline to be brought back into the operating system.

The most accurate classification of compressed air filters

To serve the needs of each customer and each type of compressed air with different densities of dirt and impurities, Naltako provides and distributes many different lines of compressed air filters based on many factors including: function, structure, gas flow characteristics, manufacturer brand, or design and connection size. Let’s let Naltako deeply analyze each type specifically.

Classification by airflow characteristics

Particulate compressed air filters

Particulate filters with a filter structure used specifically for work and environments with a compressed air supply containing large particulate dust such as: dust particles, metal particles, and plastic particles.

Removing these types of particles helps ensure the operation of pneumatic controllers achieves good and stable performance, without causing jamming situations that interrupt operations. In addition, using particulate compressed air filters will create a clean compressed air stream in production areas, helping to prolong the life of machinery and equipment.

Activated carbon filters

Activated carbon filters, or often called vapor filters for short, are specialized for systems using compressed air with odors or gases with characteristic, unpleasant smells.

Compressed air filters made from carbon and activated carbon can effectively deodorize and absorb moisture, so they are often used in compressed air systems in the agriculture, forestry, and food processing industries, or used at clinics for cases of respiratory system inflammation, unable to breathe on their own.

Coalescing filters

Coalescing filters are filters that combine full features such as air filtering, dust filtering, and water filtering. The filter works to remove gas particles down to 0.1 mm in size present in the compressed air stream. This is a filter that is currently widely used with many features, convenient for many systems.

Cold combination filters

This type of filter is manufactured with the purpose of working better in low-temperature environments with heat lower than 2 degrees Celsius corresponding to 35 degrees Fahrenheit. This is extremely necessary to help us remove moisture gas from low-temperature environments.

Compressed air intake filters

Compressed air intake filters help suck water in the filtration system. If you want the compressed air system to operate in a hazardous chemical environment, using a compressed air intake filter is extremely accurate. Besides filtering to remove toxic chemicals measuring 0.3 μm, the system also takes in water during the filtration stage.

Classification by compressed air filter manufacturing brand

In order to serve the requirement of protecting pneumatic equipment, famous brands are striving every day to launch the most quality compressed air filter equipment with the highest level of clean filtering. Below are some reputable compressed air filter brands that Naltako often advises its customers on:

AirTac brand compressed air filters

This is a famous brand in Taiwan imported by Naltako to supply to consumers in Vietnam for many years now. This filter of the AirTac brand has high quality but very affordable prices, suitable for the wallet of the vast majority of users. Besides, the equipment is diverse in many diameter sizes from 10 – 34mm suitable for workshops, assembly production facilities, processing, and bagging.

STNC brand compressed air filters

This is a brand originating from China. However, the product quality of its compressed air filters is not inferior to imported air filter types. STNC is prominent in air filter products, solenoid valves,… Therefore, users can be completely assured in using and choosing to buy products from this brand.

SMC brand compressed air filters

SMC is an industrial equipment manufacturing brand originating from Japan. SMC compressed air filters have a slightly high price; however, quality always goes hand in hand with the price level. SMC compressed air filters are designed compactly and can be easily installed on pneumatic equipment.

Applications of compressed air filters in industry

Compressed air filters are important devices in a compressed air system. The device is used to remove impurities and dust particles from compressed air before it is used in various applications. Below are some important applications of compressed air filters:

• Compressed air filters play an important role in the transportation and industrial lifting industry, helping to ensure efficient and safe operation of equipment using compressed air. The equipment is attached to the crane of industrial lifting equipment such as: Forklift ramps, dock levelers, hydraulic lift tables or hydraulic cargo lifts.
• Compressed air filters help protect air compressors, pipelines, and other equipment from dust particles, impurities, and oil in compressed air. Ensuring the system operates efficiently and with high durability.
• In industrial applications, compressed air filters are used to transport materials using pneumatic conveyor systems. Compressed air filters help prevent pipe and machinery stoppages during this process.
• In painting and abrasive blasting, compressed air is used to spray paint or grind surfaces. Compressed air filters remove dust particles and impurities from the air, helping ensure finished surface quality and preventing paint nozzle blockage.
• In medical equipment such as ventilators, compressed air is used to supply oxygen to patients. Compressed air filters ensure the supplied air is clean air, not containing dust particles and impurities.
• In the food industry, compressed air is used to control and clean products, including pushing products through pipes and equipment. Compressed air filters help prevent contaminating products with impurities.
• In automation and control systems, compressed air is used to control devices and tools. Compressed air filters help the air used for control not contain dust particles causing equipment damage.
• Aviation applications, including airports to supply clean air to aircraft and compressed air systems on airplanes to work with other equipment and systems.
• Compressed air filters are commonly used in compressed air systems of drying ovens, boilers, steam pipe systems, and air conditioning. Using compressed air filters will ensure the system is at its best.

Currently, the demand for using systems operated by compressed air filters is increasing and widening. Applied in business establishments, industrial clusters, export processing zones, to production and transportation systems. To have a well-operating system and increase efficiency for the whole system, use compressed air filter devices to eliminate residue and vapors from the outside environment.

Causes and ways to troubleshoot compressed air filters when damaged

When a compressed air filter breaks down, it is important to detect the incident early and take timely troubleshooting measures so that the compressed air system operates safely and efficiently. Below are some causes of compressed air filter breakdowns and how to troubleshoot them that Naltako wants to share with customers:

The compressed air filter cannot remove dust and water vapor

The above phenomenon mainly occurs when the air filter is installed incorrectly, or the amount of accumulated residue in the air bowl increases highly without being treated, causing a blockage at the filter head.

How to handle: ensure it is not installed opposite to the air flow direction; the inlet and outlet ports need to match the flow direction. Remove residues in the filter bowl periodically to limit overloading the filter.

Incoming air closes at the pressure regulating valve

The reason causing the above phenomenon is installing the valve in the reverse direction; if the incoming air flow is not in the forward direction, it will pull the valve flap to go out in the opposite direction. The handling method is very easy, which is to reverse the installation direction of the pressure regulator.

The pressure of the compressed air stream changes when passing through the valve

The cause of the above phenomenon is precisely because the filter becomes contaminated with dirt during its use, sealing the vents, causing a decrease in velocity and the compressed air flow passing through the valve. Users should periodically clean and wash the filter membrane and filter bowl. At the same time, do not let the pressure exceed 1600kPa of the pressure regulating valve. Compressed air filters are an indispensable product for every pneumatic control system including: Pneumatic butterfly valves, pneumatic gate valves, pneumatic butterfly valves.

Blockage by dust and impurities

Compressed air filters usually withstand pressure and filter air. Therefore, dust and impurities can accumulate in the filter. When the filter is blocked, the air flow will decrease and the pressure in the system can increase. To troubleshoot, you need to regularly check and replace the filter when needed.

Overload during use

Using an air pressure and flow rate greater than the filter’s capacity can cause damage. To avoid this, make sure you have chosen a filter capable of withstanding the pressure and flow rate suitable for your application.

Long usage time without replacing with a new filter

Compressed air filters have a usage time depending on the type and manufacturing brand, so they need to be replaced periodically. The replacement time depends on the working environment and usage level. If the filters have been used for too long, they may no longer be effective and need to be replaced with new ones.

Some notes on installation and how to use compressed air filters

Just like other parts of the compressed air system, in order to increase the lifespan of compressed air filter equipment, it requires consumers to understand how to install it correctly. Below are some important notes when installing and operating compressed air filters:

• Users must clearly understand how to install the compressed air filter, observe carefully, and install the air filter according to the correct air flow direction. At the same time, continuously clean and drain water from the filter so the machine operates smoothly.
• When compressing, air often escapes because the control valve is installed in the wrong direction. Therefore, always make sure the control valve is installed correctly. Besides, you should also set the pressure range.
• Perform periodic maintenance for the filter according to the manufacturer’s instructions. Replace the filter when the equipment is exhausted or becomes ineffective.
• Use a pressure measuring tool to check the pressure before and after the filter. The pressure after the filter should be lower than the pressure before it to ensure filtration efficiency.
• If the filter has oil and water removal features, users should replace the oil pump and water filter parts periodically.
• Ensure the filter is not in direct contact with large mechanical vibrations or impacts. Use a protective filter if necessary.

The most detailed compressed air filter quotation

Single compressed air filters have many different types, sizes, models, categories, and prices, imported and distributed by NALTAKO INDUSTRIAL JOINT STOCK COMPANY to the entire Vietnamese market share with the highest quality and best prices right now.

Coming to Naltako, you will be advised on the highest quality, cheapest compressed air filters, meeting all kinds of COCQ documents, 12-month warranty, and receiving free quotes. Contact us to get the single compressed air filter price immediately. The single compressed air filter lines we distribute include:

• Airtac single compressed air filters

• SKP single compressed air filters

• STNC single compressed air filters

• SMC single compressed air filters

CONTACT FOR QUOTE

Reputable and quality compressed air filter supply address

If you have a need to buy quality compressed air filters in Hanoi, you can refer to Naltako’s product lines. We specialize in distributing compressed air treatment equipment products from top brands in the world. Always ensuring prestige and quality for customers. This is a product imported directly by Naltako at the manufacturing factory, so the price is considered the lowest on the market today.

Customers, call now to get direct advice from our staff to survey prices and choose suitable products. Goods will be delivered directly to your hands in the Hanoi city area within the day. As for outside provinces and cities, you will receive the goods in about 2-3 days. Above are detailed sharings about compressed air filters.

Conclusion

Hopefully, with the above information, you have gained useful information to ensure the effective operation of the air compressor system. Besides, if choosing to buy compressed air filters, you should also pay attention to choosing reputable product selling facilities to limit mistakenly buying poor quality items.

CONTACT INFORMATION:

Naltako Industrial Joint Stock Company

Workshop address: Dong De, Phu Yen, Chuong My, Hanoi

Hotline: 0981.977.898

Email: nhat.mtk53@gmail.com