How To Get the Right Air to Cloth Ratio

Dust collector air to cloth ratio is a critical measure to ensure your air filtration system is performing efficiently at your operation.

Let’s first start in explaining what air-to-cloth ratio means. Air-to-Cloth ratio, which can also be known as Air-to-Media, is defined as a measurement of the amount of air passing through one square foot of filter media.Torit

Generally the lower your air-to-cloth ratio, the more effectively your system is at removing dust -from the work environment. If operate on a higher air-to-cloth ratio, one of the common issues you will encounter is a decrease in suction. This is because there is too much dust being captured by an insufficient amount of filter media. The filter cake on your bag eventually builds up too quickly; resulting in a decrease in air velocity and suction. From there it becomes a domino effect; plant air quality decreases, filters clog quicker, valve life expectancy is impacted and you’ll be performing change-outs more frequently.

To calculate air-to-cloth ratio in your existing system, the simple formula is to take the amount of airflow (CFM) and divide that by the amount of filter area within your dust collector.  For example a cartridge collector would have a normal range of 4:1 air to cloth ratio.  Environments with a large ventilation area or more pick up points require a system with a higher CFM to provide adequate suction.  To see which air to cloth ratio may be right for your project, download our air to cloth guide which provides the recommended ratio for a wide variety of applications.

Why is right Air-to-Cloth ratio important?

  • Extend your filter life
  • You minimize your operating costs
  • Meet air quality goals and requirements
  • You are running your dust collector system at it’s peak efficiency

What are the negative effects of improper Air-to-Cloth ratio?

  • Poor venting causes damage to equipment
  • Incur high pressure drops
  • Impacts your air velocity
  • Excessive use of compressed air
Related Resources:

Filter Bag Media Quiz

How to Get the Right Dust Collector for your Application

What Volume Dust Collector do I need?

4 Comments

  1. Om mishra

    I would like to know , if in one of cement plant , packing plant area our air to cloth ratio is 2.1 m3 / m2/ min . for normal cylindrical polyester bag of size 149*3.6 meter long . can we switch into Cartridrige bags ??? In the same bag filter . Air volume is 40000 m3 / hrs

    • Joyce Nagy

      Short answer is yes, you can switch to a pleated cartridge filter in place of any top or bottom load filter bags in a pulse jet baghouse. However, we need to make sure the pleated filters will work in your specific application. Dusts with moisture or that easily compact are not usually good candidates for a pleated cartridge filter as the dust will be difficult to pulse out of the pleats which can cause the filter to plug. We also need to consider the air to cloth ratio and interstitial velocity to ensure the dust can drop out of the air stream once pulsed off the filter.

      Lets make sure I didn’t make any mistakes when converting units. Your air volume is 666.7 m3/min and you have 188 filters measuring 149mm diameter x 3600mm long, correct? This gets us the 2.1 m3/m2/min air to cloth ratio.

      If you are looking to change all 188 filters to pleated cartridge filters your air to cloth ratio would drop to 0.77 m3/m2/min which should work provided the material is dry and does not compact in the pleats of the filter. If the goal is to reduce the overall number of filters you need to take into account not only the air to cloth ratio but also the interstitial velocity.

    • Joyce Nagy

      Hello Chad,

      Thank you for reaching out to us. An account manager will be in touch with you shortly to get you the information you are looking for.

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