Precoating industrial air filters, especially in baghouses and cartridge filters, is a performance-enhancing process that optimizes filtration efficiency and longevity. This technique involves applying a layer of precoat material to the filters, which promotes the capture of fine dust particles while also preventing premature filter blinding.
Read on to learn the steps for precoating industrial air filters and the benefits of precoating to ensure optimal performance and cost savings.
Steps for Precoating Cartridge Filters
This precoating process can be applied to NEW cartridge filters, 1 lb per 100 square feet of media. The typical amount of diatomaceous earth ranges from .5 lbs to 1 lb per filter.
- Preparation – Begin by ensuring that all previous dust has been thoroughly cleared from the baghouse hoppers. Turn off the hopper dust removal equipment to prevent any interference during the precoating process.
- Deactivate Bag Cleaning Cycle – Lock out the bag cleaning cycle to avoid filter bag cleaning during the precoat period. This step is critical to allow the precoat material to adhere properly to the filter media without being disturbed.
- Reduce Air Flow – Run the system at approximately 50% of the design air flow to the baghouse. This reduction is crucial to achieving an air flow velocity of about 2000 feet per minute through the inlet duct, ensuring that the precoat material does not penetrate and blind the filters.
- Precoat Injection – Inject the precoat material at a feed rate of 0.3 lbs per minute per 1000 ACFM of reduced gas flow to the baghouse. For example, for a baghouse with 50,000 ACFM, the feed rate would be 15 lbs per minute.
- Injection Points
- For baghouses operating under suction, inject the precoat through ports or inspection doors in ducts or hoppers.
- For positive pressure baghouses, inject the precoat into the duct at the suction side of the positive pressure system fan
- Inspection – Isolate each compartment and inspect the filter bags to ensure an adequate precoat cake of approximately 1/26” thick. Check the inside of the hoppers to confirm there is not a large amount of precoat dropout.
Resume Normal Operations
Once the filter bag precoating is complete, increase the air volume to normal design flow levels for the baghouse. Turn on the hopper dust removal equipment, but do not reactivate the filter bag cleaning cycle until a minimum differential pressure of 3”-4” SPWG is measured across the bags. This ensures a seasoned cake of precoat has been achieved on the filter bags prior to activation of the initial cleaning cycle.
Need More Tips for Effective Air Filtration and Dust Collection?
Glacier Technology is proud to partner with the industry’s leading manufacturers to offer the most comprehensive clean air solutions available in the world. Whatever the application, you can be assured of quality and performance, from air filtration, to dry dust and air pollution control for the most challenging environments. From start to finish, we meet all of your project needs by providing:
- System Evaluation
- Design Assistance
- Installation
- Replacement Parts
- On-site Service
The Glacier team is ready and qualified to develop your industrial dust collection solution. Contact us today to discuss your project!
