Selecting the best air compressor filter for your system is one of the best things you can do to preserve efficiency and prevent unnecessary wear on your equipment. Choosing one or more air compressor filters can be a challenging task. If you’re not sure where to start, consider the following factors as part of your decision:
Compressor Type
Every type of air compressor has its own set of fittings, filtration and other requirements you must take into account. The only way to narrow down your options for air filters is to refer to the manual and instructions for your system. If you no longer have the manual, it’s a good idea to consult a reputable company that can help you track down the specifications for your particular type and model of compressor.
Micron Rating
You want to find a good balance between filtration rating and service intervals. Finding the exact air quality requirements for your application allows you to select a filter that removes enough contaminants but doesn’t filter excess particulates. The smaller the particles a filter can trap, the smaller the holes in the filter. Smaller holes result in you having to replace the filter more often, as it becomes clogged more easily and more quickly.
For most industrial applications, general-purpose particulate filters are rated for either 40 or five microns. The required micron rating is determined by the compressor’s downstream components. Pneumatic tools and the majority of industrial equipment use 40-micron filtration, while more sensitive instruments or components use the five-micron option. There are also applications where 20, 25 or 75-micron filters are appropriate.
Using a five-micron filter when only a 40-micron filter is adequate will result in high pressure drops in the filter and shorten its lifespan, requiring you to spend more time and effort on maintenance and increasing the compressor’s consumption of energy.
Flow Capacity
Different applications demand different levels of airflow. Filters are available in a wide array of sizes, and you can find some rated for flows up to 1,000 standard cubic feet per minute. Once you know the flow required for your application, you can make the proper-sized selection by figuring out the maximum pressure drop allowable.
Compressed inline air filters manufacturers usually supply a chart showing the supply flow versus pressure drop for their filters. These charts usually show how the filter will perform in response to different levels of intake pressure. When using one of these charts, find out the inlet pressure of your application. Your operation may come in at a different pressure than the ones you see on the chart. In that case, you will need to interpolate between the curves shown to find the right flow performance and appropriate pressure.
The next step is to find out the acceptable pressure drop. If you find the flow is too low, you can reach the requirements by choosing a bigger port or body size. If the flow is higher than it needs to be, a smaller filter unit will make up the difference. You will likely be looking at multiple filters with a specific port size and different flow capacities, all from the same manufacturer.
Quality and Efficiency
Filters use a certain amount of energy based on how much they restrict flow. Filters made with attention to efficiency remove more water and particles while minimizing pressure drop. Like any product, there is considerable variation in production quality, and choosing a unit from high-quality compressed air filter manufacturers will improve your end result.
Filters that have the same flow and micron ratings can display dramatically different efficiency, based on what they are made of. The lower the filter quality, the higher the pressure drop and rate of clogging. Saving money on a filter upfront only ends up costing you more in the long run.
High-performance filters cost more initially, but their lower flow resistance and more advanced ability to trap contaminants with less of a pressure drop results in better efficiency and longer intervals between replacement.
Sorting out the quality of air filters can be a challenge because different manufacturers may be testing compressed air filtration under disparate conditions. If you are concerned with achieving optimal quality, it may be a good idea to purchase and test multiple filters side by side to more directly compare their performance.
