As the dirt-filled air makes its way to the exhaust port, it passes through the vacuum-cleaner bag. These bags are made of porous woven material (typically paper or cloth), which acts as an air filter. The tiny holes in the bag are large enough to let air particles pass by, but too small for most dirt particles to fit through. Thus, when the air current streams into the bag, all the air moves on through the material, but the dirt and debris collect in the bag.
- You can put the vacuum-cleaner bag anywhere along the path between the intake tube and the exhaust port, as long as the air current flows through it. In upright vacuum cleaners, the bag is typically the last stop on the path. Immediately after it is filtered, the air flows back to the outside. In canister vacuums, the bag may be positioned before the fan so the air is filtered as soon as it enters the vacuum.
4 Things A Vacuum Bag Must Do
Bursting – The benefits of a bag not bursting are self-evident. The two primary reasons a bag will burst are either poor materials and/or poor construction.
Poor materials; As a bag fills with debris, the weight or force of the debris pressing on the bag walls will be too great causing the bag to burst. Sometimes the force of the air as it enters the bag is enough to burst the bag. Especially if the media used is of poor quality.
Poor construction; A common problem with poorly constructed bags is the glue holding the seams together was not properly applied or dried. This is also true for the cardboard collar. If not properly affixed, the collar can separate from the bag causing a leak.
Filtration – As a vacuum operates; dirt, dust, allergens, dust mite feces, etc. are sucked up from the floor and deposited into the bag. The air traveling with it is recycled back into the room. The ability to effectively filter the air from the debris is one of the bag's prime functions. In many cases this is the main difference between a low quality and a high quality bag. A better bag will filter more of the debris vs. recycling it back into the room. For health reasons it is recommended to use a vacuum bag capable of efficiently filtering particles in the .3 to 1.5 Micron range in size.
Dust Loading – As a vacuum bag fills with debris, the tiny pores in the bag required for operation and filtering become clogged. As more pores become clogged, air flowing though the bag is restricted. This can cause back pressure causing the vacuum to lose suction. Better quality bags will dust load slowly, maintaining suction longer.
Be reasonably priced – After all it's going in the garbage!
The Importance of Good Filtration
As the illustration above shows, not all of the debris picked up by the vacuum remains in the bag...
- In fact, many microscopic particles can escape back into the air we breathe
- The most harmful particles are in the .3 to 1 Micron range in size
- When selecting vacuum bags and filters, it is crucial to look at the filtration efficiencies in the .3 to 1 Micron range
Vacuum Bag Specifications
When comparing the filtration efficiencies between vacuum bags, it is important to look at the particle sizes filtered and the air speed velocity of the particles as they impact the filter media. Smaller particles (.3 Microns) are harder to filter than larger ones (5 Microns). The slower the particle speed (Velocity) at the point it impacts the filter media, the easier it is for the media to filter. For vacuum bag tests a velocity of 30-FPM or 60-SCFM best represents the operating speed of a vacuum cleaner. For a healthy environment one should look at the filtration efficiencies in the .3 to 1.5 Micron range. These are the most harmful.
Clean With Confidence…Clean With Green Klean
Vacuum Bags and Filters
If you need additional information