Air-To-Cloth Ratio

Dust collectors are essential tools for maintaining the health and safety of your workers and equipment. For the dust collector to do its job, it must be designed, installed and maintained properly. That’s where air-to-cloth ratio comes in.

One of the key factors to keeping your dust collector operating efficiently over its lifetime is selecting the right dust collector filters. In past blogs, we’ve talked about how to save on dust collector filters and how to choose the right kind of filter media. But to know which filter is right for you, you must understand air-to-cloth ratio.

Selecting a filter with the incorrect air-to-cloth ratio can put your workers at risk. If the filtration efficiency is not high enough, workers can be exposed to more particulates, which can cause health problems. Likewise, improper dust filtering can create conditions that are ripe for explosions. To make sure your air-to-cloth ratio is right for your dust collector, here are a few important things to understand.

What is Air-to-Cloth Ratio?

Simply put, the air-to-cloth ratio of a filter is the amount of air flowing through each square foot of filter media each minute. To calculate the air-to-cloth ratio for your dust collector, divide the airflow in cubic feet per minute by the total square footage of the filter media in all of the cartridges.

How Much Air-To-Cloth Ratio Do You Need?

Generally, the higher the airflow and dust concentration that you have, the more filter media you need. This means that higher volumes of airflow and dust require a lower air-to-cloth ratio.

It is important to get your air-to-cloth ratio right. Having an air-to-cloth ratio that is too high can cause the filter to quickly become overloaded. When dust is driven deeply into the filter faster than it can be pulse cleaned, negative pressure builds and cleaning becomes less effective. As a result, the filters clog faster and need to be changed out more frequently, increasing both the cost of consumables and maintenance downtime.

A lower air-to-cloth ratio can minimize these problems. However, if the ratio becomes too low, or there’s too much filter media for the volume of particulates collected, it can severely lower the efficiency of your dust collector.

More Isn’t Always Better

Because most users understand that more filter media is better, many manufacturers try to pack as much media into their filters as possible. They pleat the media to maximize the square footage they can fit into each cartridge. The result is a filter that is packed so tightly with media that it becomes inefficient.

When pleats are packed too tightly, much of the media is not usable because it is blocked from the airstream and unavailable for filtering. This means that the filter cannot load as much dust, and pulse cleaning is much less efficient. At Camfil, we saw that this was a persistent problem throughout the dust collector filter market and aimed to find a better solution.

The HemiPleat Advantage

Camfil created a patented pleating technology called HemiPleat® that uses plastic bead separators to hold the pleats open and keep them evenly spaced. This keeps much more of the media exposed to the airstream and available for filtering. The design enables much higher airflow per square foot of media and allows more dust to be loaded onto the filter and then released when pulse cleaned. The open, breathable design maintains a lower pressure drop, cuts down on compressed air usage and reduces the energy demand on the motor.

HemiPleat filters are designed to create a safer, cleaner work environment. With HemiPleat’s open pleat design, your dust collector will be able to utilize every inch of its air-to-cloth ratio. You’ll save time and money on energy usage, compressed air, filter replacements and downtime while your dust collector works more efficiently to keep your employees safe. For help selecting the right HemiPleat filter for your application, speak with a product expert at Camfil APC.