An upright type of vacuum cleaner is a self-contained unit which has the motor, main cleaning nozzle, filtering system, etc. all built together in an overall vertical shape. All upright types today have motor driven revolving brush rolls and are used primarily for cleaning carpeted floors. They are pushed forward and pulled backward in front of the user by gripping the narrow handle extending upward from the main case.
The general upright type can be subdivided into three basic types having three unique design characteristics. They are the Traditional Upright, the "Clean-Air" Upright and the Two-Motor Upright. A traditional upright uses the basic motor, fan and bag design which has been used for decades dating back close to the time vacuum cleaners were invented. Some uprights still use this efficient design today.
The main characteristic of the traditional design is the path which the air travels as it moves through the cleaner. The air enters the nozzle near the floor and travels directly toward the suction producing fan, carrying the dirt with it. It then travels through the fan and is pushed upward into the paper or cloth filter bag. The air is filtered as it passes through the bag. Since the air is carrying the dirt as it goes through the fan this design if often referred to as the "dirty air" design. A separate air flow is used to cool the motor so the dirt and dust in the main air flow bypass it.
The air passages through which the air and dirt travel usually are relatively large. The total distance traveled by the air and dirt is often quite short, often less than two or three feet. This combination greatly reduces the resistance to air flow so large volumes of air can be moved easily, providing excellent carpet cleaning when combined with a revolving brush. The fan itself is often designed with broad fins which can handle this high volume of air. For more information of fan designs, see our article on Fan or Impeller Types & Performance.
While this design can handle a high volume of air, the actual suction (pressure difference) produced by the fan is relatively low, typically about 30" of water lift. This is typically not adequate for effective cleaning with a hose and attachments due to the much higher resistance to air flow present in the hose. Many uprights with on-board attachments use the "clean air" design which produces more suction for use with the attachments. The manufacturers of "dirty air" uprights with on-board attachments often use a high speed, small diameter fan to help overcome the lower suction produced by this design. This often can have the adverse effect of unusually high fan breakage rates and motor failures, especially when the motor's amperage is higher than about nine amps.
In summary, traditional uprights typically produce excellent carpet cleaning results but less than desirable results when a hose and attachments are used. This design can be identified by looking at the filter bag and the supporting container. If the paper bag is supported by a flexible outer cloth or vinyl bag you can be sure that it is this design. If the bag is supported by a rigid enclosure, open it and look for seals around the edges. If none are present, it is probably this design as well. If the rigid bag enclosure is sealed and a foam or fiber filter pad is at the bottom of the enclosure, it is probably the "clean air" design.
Next Vacuum Cleaner Type: "Clean Air" Upright Vacuum Cleaner