A vacuum sweeper is a mechanical device that uses moving air to suction dirt, dust, and other particles from surfaces. They are particularly helpful in cleaning heavy, textured materials like upholstery, draperies, and carpets. This device is also called a vacuum cleaner, or sometimes just a vacuum.
Differential air pressure creates the suction action in a vacuum sweeper. Air pressure inside the machine is reduced to lower than atmospheric pressure, usually by an electric fan. This difference in air pressure causes air to move from the higher pressure area outside the machine to the lower pressure area inside the machine. Dirt is carried by the air. The air passes through a bag, where the dirt is collected, and the air is discharged. Often, a vacuum sweeper has rotating brushes that beat more dirt out of the surface so that it can be suctioned away.
Vacuum cleaners come in a number of forms. Upright and canister are the two basic types of vacuum sweeper. Many specialized forms have been also been developed.
The upright version has a handle and bag attached to the cleaning head. This type usually has a beater bar or brush roll to dislodge dirt by a combination of vibration and sweeping. It has two basic designs for moving air.
In the direct air system, a large fan is positioned in front of the bag and very near the suction opening. The dirt is sucked through the opening and into the bag. This is the older design, and it very efficient for horizontal surfaces like carpets.
The indirect air vacuum sweeper has the motor and fan mounted behind the bag, so that dirt is removed from the air stream before the air passes through the fan. This type of vacuum sweeper is equally effective in cleaning both horizontal and vertical surfaces, but it requires more power than the direct air upright vacuum cleaner.
The canister vacuum sweeper places the motor, fan, and bag in a separate unit, which is connected to the cleaning head by a hose. It is usually less effective than the upright design, but it is lightweight and easy to maneuver. Some canister vacuum cleaners have beaters in the cleaning head.
A central vacuum sweeper has its motor, fan, and dirt bag permanently mounted in a central location. Ducts connect the bag to vacuum inlets positioned through the building. The pickup head and a long hose are carried from one room to the next. The bag is large and usually needs to be changed only about once a year. This provides high suction and does not recirculate any dust back into the room. This type is also called a ducted or a built-in vacuum cleaner.