Baghouse Cleaning

First of all what is the definition of a Baghouse (or Filter Plant as it is referred to in Europe) - it is a generic name for Air Pollution Equipment which uses a range of filter bags/ fabric types to separate particulate (dust, ash, powders etc) from the exhausting air stream. Not only is this an essential process in order to recover the product being manufactured, it is also required by the Environmental Protection Agency (EPA) to ensure that all exhaust industrial gasses are particulate (dust) free or at least comply with their extremely tight particulate emission limits. They are particularly concerned with particles that are 10 micrometers in diameter or smaller because those particles generally pass through our throat and nose and enter the lungs thus causing serious heath problems.

There are generally three different types of Baghouse namely;

Reverse Air Baghouse - these are much larger than Shaker Collectors and have a customary round shape. The tubular filter bags (or socks) are supported on wire cages and hang down inside the filter with the dirty gas stream being sucked through the outside of each filter bag and the clean air being exhausted from inside each sock by an external fan. The problem with this system is that eventually the powder builds up on the outside of each sock and if no action was taken, the filter would cease to be effective and the filter bags ruined. To try and overcome this problem, this type of baghouse employs a series of simple rotation fans which blow air down the inside of each sock in turn to try and dislodge the powder adhering to the outside of each bag. Thus they use a high volume of low pressure air to try and clean the filter bags. This action is only partially successful and so the efficiency of the filter begins to drop also the bag quality deteriorates. Filter bag replacement is a very dirty, time consuming and costly operation and so plant operators are always looking at ways to lengthen the period between bag changes without detrimental effect on the efficiency of the filter's performance.



Reverse Jet Baghouse - these are now the most commonly used baghouse filters. Unlike the reverse air baghouse which uses high volume - low pressure air as a cleaning tool, these type use high pressure - low volume air as a cleaning tool, the air being compressed air at around 5 - 6 bar pressure. This type of baghouse varies greatly in both size and shape and is certainly the most versatile and widely used type. Cleaning of the bags is performed 'on-line' by means of compressed air jets being 'blasted' down each row of filter bags in turn. One drawback is that they can use a high quantity of Compressed air and should this compressed air contain any moisture then this water vapour could reduce the efficiency of the cleaning process by blinding the filter bag material.

Even with this more popular type of baghouse filter plant, there still remains three distinct and costly problems. Firstly filter bag cleaning with compressed air jets does drop off quite considerably with time or excess material load passing through the filter. Secondly bag replacement is becoming ever more expensive, especially if the bags are made from special material or have a particular 'finish' on their outer surface. Thirdly, material build up also occurs on the side walls, between filter bags and in the hopper discharge section. This in turn can cause severe cross contamination with the only previous remedy, to shut down the unit and conduct hazardous manual internal cleaning. Thankfully another simple, automatic and effective remedy can now be employed -

Acoustic Cleaners can offer the following benefits in reverse jet baghouses:-

The maintenance of both pulse jet and reverse air filters in terms of replacement bag and downtime is an ever increasing financial burden on the engineering budget. The cost of replacement bags has soared in recent years as has the costs associated with enforced, unscheduled plant shut down due to loss in baghouse filter efficiency.

The Primasonics® range of Acoustic Cleaners has been successfully employed over a wide range of filter types and sizes to offer:-

• Significant increase in filter bag life
• Continual lower pressure drops across the bags
• Continuous cleaning of all internal surfaces
• Complete evacuation of the filter hopper
• Reduction in compressed air usage

The appropriate model of Primasonics® Acoustic cleaner is easily installed, is fully automatic in its operation and requires little or no maintenance. Below are a couple of installations examples of Primasonics® Acoustic Cleaner installations below. So take the first positive step to improving baghouse efficiency and reducing maintenance costs and complete our online Filter Questionnaire Form. Alternatively download the PDF equivalent here, complete and return it to us. Either way we can give you a quotation plus details of a 30-day free trial offer.