Although you’ve probably never given them a moment’s thought, your filter bags in your baghouse are a marvel of modern engineering. Invented in the 1970s, they are manufactured from woven or felted fabric that can withstand extremely high temperatures (up to 177 degrees Celsius). They exist solely to breathe in extraordinarily small dust particles so you don’t have to, and in our view, there are too many operators around who neglect to maintain them as they should, compromising the air quality of their facilities and in turn, the respiratory health of their staff.
There are several types of baghouse, defined mainly by the method used to clean them, the most common of which are:
Mechanical shaker – boasting the simplest design, this variation, which comes in a number of sizes, is frequently used in the mineral processing industry. Consisting of tubular filter bags which hang down from horizontal beams, dirty air enters the baghouse at the bottom and the dust particles are trapped on the inside of the bags before being blown out the top. Cleaning involves shaking the beams with a motorised shaft, which causes the dust layer inside the bags to fall into the hopper below.
Reverse-air baghouse – requiring more maintenance than mechanical shakers, this unit also trap dust on the inside of the filter bags, but it is cleaned by a reverse injection of air, with the subsequent air pressure partially collapsing the bags, causing the dust cake to fall off. The advantage of a reverse-air baghouse is that it is compartmentalised, meaning that it can be operated continuously even while one compartment is being cleaned.
Pulse jet baghouse – the bags in this unit are supported by a metal cage with the dirty air flowing from the outside in. This results in the dust cake forming on the outside of the bags, which are regularly hit with very short bursts of compressed air, creating a shockwave that cause the bags to flex and shed their dust load. Pulse-jet baghouses can also be operated and cleaned continuously without being compartmentalised, as the cleaning cycle is so short.
The average baghouse filter has a rather variable life-span of 1-3 years, which will depend on a number of factors, such the material that the dust is comprised of and how much filtering is required on a weekly basis.
If your filter bags are forced to run 24/7, regularly exposed to consistently high temperatures and corrosive particles and the baghouse in which they are contained is physically too small for the task at hand, then they are unlikely to last longer than a couple of months.
Bags that haven’t been sufficiently cleaned will accumulate a significant ‘dust cake’, meaning that they are no longer fit for purpose. Sparks can burn holes in the fabric (after all, it’s not 100% fireproof), and wear and tear from abrasion along with damage from corrosive chemicals can all contribute to shortening the life of your bags, so it’s vital that they are regularly inspected.
Cleaning can be manual or automated, although in our experience we sometimes find that automated cleaning results in bags being cleaned too often, which ironically, can also shorten their lifespan.
Ensuring your filter bags are kept in good nick will keep energy consumption and wear and tear down, production up, and the Labour department out of your workplace. Most importantly? It will keep your staff safe, after all, that is why baghouse filters were invented!
If you would like some assistance in setting up a regular cleaning and maintenance schedule for your baghouse, Clint and the team at BTS Engineering are always happy to help, so call us on 0800 885 383 or email bespoketradesolutions@gmail.com today and we’ll take care of the rest.