Canister Vacuums That Use Water

Bagless Vacuum History

• The earliest vacuum cleaners worked by using a motor to draw air into a cloth or paper bag inside the machine's canister. The air was able to pass through the pores in the bag, but dirt and dust drawn in with the air was unable to pass through and was trapped in the bag. The problem with bags was that their pores quickly became clogged with dirt, which dramatically reduced the vacuum's suction power. In the 1930s, Clarence Brock solved the problem by designing an early bagless vacuum, a canister machine that directed its incoming air stream so that dirt was deposited in a receptacle without the use of a bag.

Early Water Filtration Vacuums

• In 1936, Rexair designed a bagless canister machine that used water to filter dirt and debris out of the air stream. It worked by directing the air through water in the bottom of the dirt cup. In theory, the dirt and dust pulled in with the air would get wet; it would then be too heavy to exit through the machine's exhaust and would remain in the water. The Rexair water-filtration machines were given the name Rainbow in 1955, and modern water-filtration vacuums operate on essentially the same principle as these early models.

Water Filtration and Allergies

• Although water-filtration vacuums are sometimes promoted as beneficial for allergy sufferers, the claims are not substantiated. In fact, studies published in the Journal of Allergy and Clinical Immunology and the American Lung Association's Respiratory Journal found that water-filtration vacuums actually increase the amount of cat allergen in the air when they are used, possibly because small particles are easily transported in the tiny water droplets created and exhausted by the machines. In addition, water in the dirt cup introduces the potential for mold growth in the vacuum, another concern for allergy sufferers.

Certified Models

• The Asthma and Allergy Foundation of America has developed a set of standards by which it certifies consumer products, including water-filtration vacuums, which are considered to be "asthma and allergy friendly." These standards for vacuums include specifications for the machine's ability to remove allergens from carpets and to prevent allergens from becoming airborne during use. Certified vacuums should also not substantially increase humidity in the air or carpet when they are used, and their manufacturers should provide customers with a maintenance schedule that reduces the possibility of mold growth in the machine.