What is A Coalescing Filter For Air Compressor
The compressed air coalescing filter is a kind of high-precision filter. Firstly, compressed air passes the pre-filter or primary filter. It can remove many particulates. Then they flow through the coalescing element from the inside out. The liquid flow rate will be greatly reduced. The dispersed tiny droplets combine with each other in the coalescence layer. So they will gather together. Finally, become large liquid particles. These processes are called coalescence. This liquid contains water and oil. Finally, the automatic drain will discharge the liquid. Therefore, it realizes the air-liquid separation. That is, it also achieves compressed air filtration.
Technical Specifications of Compressed Air Coalescing Filter
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Application gases
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compressed air / non-corrosive air
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Air capacity of coalescing filter for air compressor
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1.0m³/min to 22m³/min
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Working pressure
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Std.7 Bar / Max:16 Bar
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Pressure loss under full load
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0.02MPa to 0.025MPa
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The working temperature of the airline filter
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Max 80℃
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Compressed air filtration accuracy
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5 micron, 1 micron and 0.01 micron
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Coalescing filter element
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high-quality HV glass fiber filter paper
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Filter housing material
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die-cast aluminum alloy (100% pass pressure test)
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Type
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compressed air filter with automatic drain, differential pressure gauge, and liquid level mirror
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Function
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dust particulate filtration, oil aerosols filtration, and water & moisture removal
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Filter element lifetime
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8000 hours
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Outer casing lifetime
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at least 10 years
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Specific Data of Our Filters
| Filter Model | Pipe Size | Air Capacity | Air Capacity | Configure |
| LY-OMD017 | Rc1/2 inch | 1.0 m³/min | 35.3 cfm | DP indicator, automatic drain, liquid level mirror |
| LY-OMD017a | Rc3/4 inch | 1.5 m³/min | 53.0 cfm | DP indicator, automatic drain, liquid level mirror |
| LY-OMD030a | Rc1/2 inch | 1.8 m³/min | 63.6 cfm | DP indicator, automatic drain, liquid level mirror |
| LY-OMD030 | Rc3/4 inch | 2.0 m³/min | 70.6 cfm | DP indicator, automatic drain, liquid level mirror |
| LY-OMD040 | Rc1 inch | 2.4 m³/min | 84.7 cfm | DP indicator, automatic drain, liquid level mirror |
| LY-OMD058a | Rc3/4 inch | 2.8 m³/min | 98.8 cfm | DP gauge, auto drain, liquid level sight glass |
| LY-OMD058 | Rc1 inch | 3.6 m³/min | 127.1 cfm | DP gauge, auto drain, liquid level sight glass |
| LY-OMD080 | Rc1 inch | 4.8 m³/min | 169.4 cfm | DP gauge, auto drain, liquid level sight glass |
| LY-OMD145 | Rc1-1/2 inch | 7.2 m³/min | 254.2 cfm | DP gauge, auto drain, liquid level sight glass |
| LY-OMD220 | Rc2 inch | 12.0 m³/min | 423.7 cfm | DP gauge, HAD20B drain, liquid level sight glass |
| LY-OMD220a | Rc2-1/2 inch | 14.0 m³/min | 494.4 cfm | DP gauge, HAD20B drain, liquid level sight glass |
| LY-OMD330 | Rc2 inch | 18.0 m³/min | 635.4 cfm | DP gauge, HAD20B drain, liquid level sight glass |
| LY-OMD330a | Rc2-1/2 inch | 22.0 m³/min | 776.6 cfm | DP gauge, HAD20B drain, liquid level sight glass |
Kind note: DP means the differential pressure. And these compressed air coalescing filters are thread connection.
Advantages of Coalescing Filter For Air Compressor
(1) Use High Quality Raw Materials And Spare Parts
Firstly, our filter element adopts the American HV brand paper. So, it can effectively guarantee the filtration accuracy and effect. Because of the stainless steel inner mesh, the anti-corrosion strength is high. Also, there is a stainless steel mesh support on the outside. Therefore, it can ensure sufficient strength and stability of the filter.
In addition, the compressed air filter housing is made of aluminum alloy. Because of the one-piece die-casting, the structure is compact. And long-lasting. Besides, the casing has undergone strict surface treatment. That is, it passes cleaning, degreasing, electrophoretic treatment, and spraying. Thus, it improves the durability. The working temperature can be up to 80℃. And application pressure of our compressed air coalescing filter is Max 16Bar.
(2) Pass The Strict Pressure Test And Filtration Accuracy Test
Each housing passes a 100% pressure test twice. Semi-finished products do a leak test. The finished product also does a pressure test again. Therefore, it can prevent leakage of the compressed air coalescing filter. Avoid wasting energy. At the same time, fully guarantees the interests of users.
In addition, our coalescing filter for air compressors also passes strict tests for filtration accuracy and efficiency. The test refers to the standard ISO8573.1-2010. The oil content after filtration by AX filter is ≤ 0.005ppm @21℃. And 0.01μm filtration efficiency is 99.98%. The 1.0 μm filtration efficiency is 100%.
(3) Equipped With Functional Accessories
Firstly, the coalescing filter is with an automatic drain. It can remove moisture in the air compressor system in time. So guarantees compressed air quality. At the same time, it can protect the service life of the filter element.
Secondly, the filter has a differential pressure gauge or indicator. They can indicate the working condition of the filter element. If blocked, the pointer will be in the red zone. So it indicates that we need to replace the filter element.
Thirdly, the regular compressed air coalescing filter also has a level mirror. On the one hand, we can observe the condition of the automatic drain. On the other hand, we can also judge if there is air pollution in front.
(4) With Low Pressure Drop
The coalescing filter for air compressor adopts a smooth elbow design. It greatly reduces turbulence. Therefore, it can reduce the pressure loss effectively. In addition, we use HV filter paper. Its high filtration effect can also effectively reduce the residual pressure drop.
The upper and lower structures of filter housing are integrated. The upper part is the “tube head”. And the lower body is the “tube body”. The new deflector elbow replaces the old 90° straight corner. The air inlet of the filter is designed in the shape of a “bell mouth”. Therefore, it can reduce the resistance caused by gas turbulence. Compressed air flow is smoother. So it can greatly reduce pressure loss.
Besides, the upper part of the filter element has an internal gas flow distributor. It also reduces turbulence. And effectively distribute the compressed air passing through the filter element. It is beneficial to improve the air distribution and balance efficiency inside. So it will increase the filter area. At the same time, will also reduce the pressure drop.
Working Principle of Compressed Air Coalescing Filter
High-efficiency coalescing filters are different from ordinary filters. It has an irregular fiber mesh. Ordinary filters work on the principle of sieving. That is, particles larger than the filter gap are trapped. Particles smaller than the gap will pass through the filter. However, the oil droplet sizes are usually less than 2 μm. Ordinary filters are more effective for oil droplets than 5 micro. So they cannot separate enough oil from the compressed air.
Compressed air coalescing filter works on a different principle. Their fiber diameter is similar to the diameter of the captured particles. All are between 0.5μm-2μm. Solid particles or droplets in this size range encounter a fiber with a diameter in the same range and stick to it. This kind of adhesion force is also namely van der Waals force.
There are three mechanisms that allow filters to capture the most particles. That is direct interception, inertial collision, and diffusion. Diffusion is also called Brownian motion.
Direct interception occurs when a particle passes through a fiber gap smaller than its radius. In this case, the particles will come into contact and be aggregated. As a result, an inertial collision occurs. Brownian motion is valid for particles smaller than 0.6 μm. Besides, it can extend the effective range of the high-efficiency filter to 0.05μm or smaller particles.
Its capture mechanism is also effective for water & oil droplets. The solid particles are attached to the fibers at the point of collision. And they do not move. But the droplets will move down the fiber to the intersection. The aggregated droplets grow larger. Finally, they appear on the surface downstream of the filter. Then it is continuously drained from the fitter system. This process is called agglomeration or coalescing.
Why Need Compressed Air Filter With Automatic Drain
Precision filters are the most common configuration in air compressor systems. Although not very expensive, it has an important role. High-efficiency coalescing filters can remove particulate and oil aerosols from compressed air. More importantly, it can remove water mist and odor.
(1) The Necessity of Using A Precision Filter
The hydraulic system has high requirements for the cleanliness of the hydraulic oil. Likewise, pneumatic systems also have high requirements for compressed air. The compressor discharges air. But pneumatic devices cannot be them directly.
Air compressors suck in air containing moisture and dust. After compression, the air temperature will increase to above 100°C. At this time, part of the lubricating oil inside will also become gaseous. Therefore, compressed air contains oil, moisture, and dust. Besides, it is a high-temperature air. If sent directly to the downstream, it will reduce the reliability and service life of the pneumatic system. The resulting losses will be huge. It will be much more than the cost and maintenance of pneumatic devices. So the compressed air coalescing filter is absolutely necessary.
(2) Hazards of Water And Impurities in Compressed Air
Moisture has a rusting effect on pneumatic components and pipes. And cause the moving parts to become stuck or worn. Finally, make the pneumatic components malfunction and leak. In cold regions, moisture freezing can cause pipes to freeze. In addition, dust in the compressed air will wear down the cylinder. So reduce the service life of the system.
To sum up, we should use the coalescing filter for air compressor. This can improve the quality of compressed air. At the same time protect our precision equipment.
FAQs
Q1: What’s the type of housing: cast shell or welded shell?
A1: Our compressed air filter housing is cast aluminum alloy. So our filter has high compressive strength. The maximum pressure can be 1.6MPa. And the service life is long. At least it can be used for 10 years.
Q2: How often to replace the filter element?
A2: It usually needs to replace the element after using it for 6000~8000 hours. Or if you find the pressure difference is more than 0.4 bar, please replace it.
Q3: What kind of compressed air coalescing filter to buy?
A3: If there is no desiccant air dryer, it usually needs to buy the three-stage compressed air filter. That is the AO, AA, and AX filters. Among them, AO is pre filter or primary filter. And AA filter is for dust filtration. In addition, the AX filter is for oil vapors & aerosol filtration. Of course, if the air compressor system has water, you can also buy a WS cyclone water separator.
If there is a desiccant dryer, it needs the four-stage coalescing filter for air compressor. That is the AO, AA, AX, and AA filter. Because of the presence of adsorbent dust, the last AA filter removes them. For more information about compressed air coalescing filters, pls contact us.
