10/06/2022
Low Moisture Soil Encapsulation
Carpet cleaning via the bonnet method utilizes a low-speed rotary floor scrubber and a piece of fabric (usually cotton, with nylon strips for scrub power) disk or pad, called a bonnet. A cleaning solution (specially formulated for this process) is applied to one small area of the carpeting at a time, which is then “massaged” with the bonnet mounted under the floor scrubbing machine.
The agitation and chemical action free the soil from the carpet fibers; much of it is absorbed into the bonnet, which is dunked in fresh solution and wrung out every 100 or so square feet to dispose of the picked-up soil. Once dry, the carpet is thoroughly vacuumed to remove the remaining soil entrapped (encapsulated) in crystallized chemicals.
There are various advantages to low moisture processes over hot water extraction (commonly called “steam cleaning”): less moisture introduced into the carpet, thus limiting the chance of over-wetting, speeding up dry-time (limiting the possibility of mold and fungal growth); environmentally, less water (by about 95%) and less chemical used; less water introduced into the carpet backing avoids shrinkage or tearing of fibers, and bleeding and discoloration. Finally, we experience better worker productivity, so we can clean the carpet more frequently at a similar annual cost.
Rotary cleaning (shampooing)
Carpet cleaning using a low-speed (175 rpm) rotary floor scrubbing machine equipped with a nylon cleaning brush. The solution is applied to the carpet, usually from a tank on the floor scrubber, and fed through holes (“shower feed”) in the brush’s backer block, aggressively brushed into the carpet, and allowed to fully dry. Thorough vacuuming then removes soil and crystallized shampoo from the carpet.
Rotary shampooing tends to be more aggressive than bonnet cleaning; while harder on the carpet, it also tends to “grind out” more soil. It’s commonly used for “heavy duty” or restorative cleaning, often followed by extraction (without added cleaner), to dilute and rinse out soil, rather than waiting for dry vacuuming.
Hot water extraction (NOT steam cleaning)
Sometimes (erroneously) called “steam cleaning” – Carpet backing is bonded to the carpet fibers at temperatures near 200 degrees; real steam (212 degrees F.) would melt that adhesive that binds the carpeting to its backing material. Steam cleaning equipment manufacturers bought a lot of carpeting for the victims of this “technology”!
Extraction uses a pressure nozzle to propel solutions (cleaning; deodorizing; fungicidal, among others) into the carpet, and a wand/wet vacuum system to pull it back out, along with suspended dirt. It works primarily by diluting or solubilizing carpet contaminants. It is effective at pulling out deep soil, residual shampoo, or deep stains.
Extraction by itself does little to agitate carpet fibers, so ground in soil can be a problem. Consequently, it’s often used in conjunction with rotary shampooing for cleaning of grossly soiled carpeting (carpeting in auto shops, for instance) or in “restorative” cleaning, or in pulling out relatively fresh beverage spills (by putting massive doses of water into the carpet, diluting the beverage, and sucking it back out).
Carpet protection (post-cleaning)
Application, usually after carpet cleaning, of a chemical coating designed to prevent staining of carpet fibers by water-borne contaminants or oily substances (pizza always lands cheese side down – doesn’t it?). After protection, ongoing carpet spot removal becomes more effective; the next full cleaning becomes both more effective and easier to perform.
Some carpet protectors are also designed to minimize the attachment of dust, dirt, and dander to the carpet’s fibers, thus allowing more soil removal with regular vacuuming; the carpet looks better longer, exhibits less wear (less gritty soil left behind for foot traffic to grind into and damage carpet fibers), and leaves less fine soil to become airborne during the day, impacting indoor air quality.