Bagless vacuum cleaners are vacuums that do not require a separate collection bag inside of them. Bagless vacuums use channeled air to deposit all of the grit and grime in a container that catches everything and gets emptied after each use. There aren't any disposable bags to buy with bagless vacuums, so they are more convenient and have a lower cost of ownership. Also, if you vacuum up something valuable with your bagless vacuum it's very easy to open the catch-all and retrieve it.
There are two ways that the bagless vacuum cleaners separate the dirt and dust from the incoming vacuumed air stream. They are:
Filtered cyclonic: This method uses an air pattern to spin the vacuumed dust and grit in a cylinder of the bagless vacuum cleaner. The heavier particles are forced against the wall of the cylinder. They drop to the bottom of the collection bin inside of the bagless vacuum. The faster the dirty air spins, the better the separation is. The small and light particles remain in the center of the cylinder. They are later removed by an exhaust filter before exiting the bagless vacuum.
The Dirt Cup: There are still no disposable bags with this bagless vacuum, but this method is not cyclonic. Debris and dust are filtered from the air stream by a cloth upper bag. The dirt builds on the inner wall and forms a "filtering dirt cake." The movement and operation of the bagless vacuum cleaner eventually cause the dirt cake to fall off of the inner wall and into the cup. This method is mostly used in commercial bagless vacuum cleaners.
Bagless vacuums are great for allergy sufferers because instead of dealing with an overfilled vacuum bag which will end up releasing dust back into the air and onto the floor, they can just take the whole bagless vacuum to the garbage can to empty it. Some even have transparent collection containers that make it easier to see when the bagless vacuum is ready to be emptied.
Also, there will be no going to the store to locate the correct replacement vacuum bag with a bagless vacuum cleaner. It seems like every bagged vacuum needs a different kind of bag. Sometimes the manufacturers would even stop making a certain type of bag so that the users of those particular vacuums would have to purchase new vacuum cleaners. There is no need to deal with these issues with a bagless vacuum.
Bagless Vacuums: the hassle free cleaners!