Carpet Cleaning Methods
There are several basic methods for cleaning carpets The most common are:
- Carpet Shampooing
- Dry Powder Method
- Bonnet Cleaning
- External Extraction
Carpet Shampoo Method
The shampoo method generates a lot of foam in the carpet which is allowed to dry. The resulting residue attracts the soil, and is vacuumed up the next day. Carpet shampoo products must have the following characteristics which dictate their ingredients:
- High foam levels to reduce wetting.
- Stable foam.
- Lubricants to reduce damage to the carpet fibers.
- Dry to a non-sticky residue.
The carpet shampoo must contain a foamy chemical and often a solution with brighteners in it, which make the carpet look nice. However, eventually the dirt will reappear and, just as with the foam method, the shampoo residue will attract dirt itself. The brighteners will eventually give the carpet a yellow cast which cannot be removed.
Two primary types of machines used for this process cylindrical foam and rotary shampoo.The Cylindrical Foam Shampoo machine uses an air compressor to create dry foam before the foam is applied to the carpet and then agitated with a revolving cylindrical brush which combs the foam through the carpet pile. This method can leave dirt trapped in the carpet pile, so the carpet must be thoroughly vacuumed before and after cleaning.
The Rotary Shampoo method uses an ordinary rotary floor machine (the same kind used for stripping wax), sprays shampoo onto the carpet from a dispensing tank, and a rotary brush whips the detergent to a foam. Most carpet mills and carpet fiber producers discourage the use of rotary brushes on carpet because of the potential damage that can occur. Over wetting is common with this method which can cause jute straining, shrinkage, and odor.
Shampoo methods are inferior due to poor cleaning plus resoiling problems. The Rotary Shampoo method can damage the carpet, especially cut pile (which is what most residential carpet is).
Dry Power (Carpet Absorbent Cleaners)
In this method, dry absorbent compound is sprinkled over carpet or worked into the carpet with a machine. This purpose of this cleaner is to attract and absorb soil. Mechanical agitation from a brush works the cleaner through the carpet. These products usually contain an absorbent carrier, water, detergent, and solvent. The theory is that the liquids dissolve the soil and this soil/detergent/solvent mixture is absorbed into the carrier and is then vacuumed up. They are often used with a detergent prespray in heavily soiled areas. The carpet must be thoroughly vacuumed before and after cleaning.
Very thorough vacuuming should be used to ensure that most of the carrier comes out of the carpet. With the extremely fine powder types, indoor air quality can be reduced. If a white powder starts appearing on shoes and cuffs of pants, too much was used and it was not thoroughly vacuumed up. A common problem is for this white powder to reappear after wet extraction cleaning.
This cleaning method has the advantage of no drying time for interim maintenance, since little water is used. This makes if a common maintenance cleaner.
Bonnet Shampooing is simply an adaptation of hard floor spray buffing to carpets. This method for carpet maintenance consists of the use of a rotary or oscillating brush adapted with a stiff brush or drive block designed to drive wet, damp or dry pads. The carpet can be sprayed with the cleaning solution and/or the pads can be soaked in the cleaning solution and squeezed lightly before placing the pad under the driving brush.
Shaw Industries, the world's largest carpet manufacturer, suggests not using this method due to pile distortion and fiber damage. This method has very limited capability for soil removal and leaves much of the detergent in the pile. As a result, rapid re-soiling often occurs. The spinning bonnet may also distort the fibers of cut pile carpet and leave distinct swirl marks. Check with your carpet manufacturer because many leading carpet mills recommend against this method of cleaning.
This is the cleaning method recommended by nearly all carpet manufacturers and carpet fiber producers because research indicates that it provides the best capability for cleaning.
This method is classified as "deep cleaning", whereas the others are considered "light surface cleaning" because they are incapable of removing soil buried deep in the pile. Also, the other methods leave large amounts of cleaning agent in the carpet after cleaning.
This method is frequently called "steam" cleaning due to the fine spray of water used to force dirt out of the carpet which is sucked up by the vacuum slot immediately in front of the spray. This process consists of spraying a solution of water and detergent into the carpet pile and recovering the water and soil with a powerful vacuum. This can be done from a truck-mounted unit outside the home with only the hose and floor tool brought inside, or by a portable, system brought into the home or office.
From a health standpoint, the truck-mounted system is preferred because the dirty air and humidity are exhausted outside rather than recirculated within the building. Additionally, truck-mounted systems usually are more powerful than portable units, do a better cleaning job, and dry the carpet more quickly.
Depending upon the equipment, temperatures may range from cold tap water to boiling hot water. The choice of the proper cleaning system is extremely important. Check with the carpet manufacturer for recommendations.
Carpet Cleaning Frequency:
If carpet is cleaned before it becomes too unsightly, the cleaning chore will be easier and more successful. Allowing the carpet to become overly soiled may result in irreversible damage. Carpet in a typical household should be professionally cleaned every 12 to 24 months depending upon the number of residents, amount and type of activity, and carpet shade or color.