Top 5 Types of Carpet Cleaning Methods
5 most commonly used carpet cleaning methods
By Anna Chan
Carpet cleaning, for appearance, and the removal of stains, dirt, and allergens is done through several methods.
Clean carpets are recognized by manufacturers as being more visually pleasing, potentially longer-lasting,
and probably healthier than poorly maintained carpets.
The process of carpet cleaning includes the process of removing stains, dirt and allergens.
Carpet traps dust and dirt, therefore clean carpets promotes good indoor air quality, is visually pleasing to the eye and
feels more comfortable on skin.
There are several methods in the industry, but we are only going to talk about the top 5 carpet cleaning methods mostly commonly
used by carpet cleaning companies.
A 98% biodegradable or others, slightly moist absorbent cleaning compound may be spread evenly over carpet and brushed or
scrubbed in. For small areas, a household hand brush can work such a compound into carpet pile; working like “tiny sponges”,
the attracted cleaning solution dissolve dirt, dirt and grime is attracted/absorbed to the compound, after a short drying time
(the cleaning solution which is attracted to the compound must evaporate), it will be removed with a vacuum cleaner,
the drier the better, leaving carpet immediately clean and dry. But it’s very difficult to remove all residues,
the residues can cause allergies and biological compounds may cause discolourations on carpets. For commercial applications,
a specially designed cylindrical counter-rotating brushing system is used, without a vacuum cleaner.
Machine scrubbing is more typical, in that hand scrubbing generally cleans only the top third of carpet.
In the 1990s, new polymers began literally encapsulating (crystallizing) soil particles into dry residues on contact.
In the conventional cleaning process surfactant molecules attach themselves to oily soil particles, suspending them (emulsification)
so that they can be easily rinsed away. Surfactant (detergent) molecules and emulsified soils which escape being rinsed away,
remain in the fibre and continue to attract soiling, causing the condition of the carpet to degenerate; often re-soiling faster than
before it was subjected to the cleaning process.
Encapsulators are speciality detergent polymers which become part of the detergent system.
As drying occurs (20-30 min. drytime), after cleaning, these encapsulators bind the detergent molecules and residual soils in a brittle, crystalline structure.
Detergent and soil particles can no longer attract other soils and are easily removed by dry vacuuming. In addition to binding the detergent
and soil residues the encapsulation chemistry coats the clean fibre with the same brittle film. This reduces the fibre’s affinity for oily and particulate soils.
As this brittle film”breaks away” and more soil is removed, the appearance of the fibre improves as opposed to soiling more rapidly.
Products which also employ fluorochemical technology, display dramatically extended anti re-soiling time periods.
Cleaning solution is applied by rotary machine, brush applicator, or compression sprayer. Dry residue is vacuumable immediately (20-30 min. drytime),
either separately or from a built-in unit of the cleaning-system machine.
After a cleaning product is deposited onto the surface as mist, a round buffer or “bonnet” scrubs the mixture with a rotating motion.
This industry machine resembles a floor buffer, with an absorbent spin or oscillating pad that attracts soil and is rinsed or replaced repeatedly.
The bonnet method is not strictly dry-cleaning.
To reduce pile distortion, the absorbent bonnet should be kept well-lubricated with cleaning solution.
It is not recommended to dunk the bonnet in a bucket of cleaning solution and then wring it out with a mop-bucket wringer, as this will make the bonnet too wet.
It is important to change or turn the bonnet early, as bonnets can become filled with soil in just a few hundred square feet. Once loaded with soil,
the bonnet will not hold any more; instead, it simply moves the soil from one area to another. An overly wet bonnet also deposits residues that attract soils when they are dry,
creating the need to clean more often.
It is recommended for robust and not for high floor carpet, it swirls the floor.
It distorts pile and grinds dirt deeper in carpet fiber, and also has an abrasive effect.
When there is a large amount of foreign material in the carpet, extraction with a wet process may be needed.
Normally, the spin-bonnet method may not be as capable of sanitizing carpet fibers due to the lack of hot water, for this a special thermo machine is needed,
here the buffing machine is equipped with a heating, to heat up the bonnet, but a post-cleaning application of an antimicrobial agent is used to make up for this.
A small amount of water is required with spin-bonnet carpet cleaning. It only cleans the top of the carpet 1/8 inch but it is very fast for wide areas.
However, bonnet cleaning is not the best mechanism for completely removing the chemical that is pre-sprayed onto a carpet.
It is recommended that only surfactant free or encapsulating products are used.
Wet shampoo cleaning with rotary machines, followed by thorough wet vacuuming, was widespread until about the 1970s,
but industry perception of shampoo cleaning changed with the advent of encapsulation.
Hot-water extraction, also regarded as preferable by all manufacturers, had not been introduced either.
Wet shampoos were once formulated from coconut oil soaps; wet shampoo residues can be foamy or sticky, and steam cleaning often reveals dirt unextracted by shampoos.
Since no rinse is performed, the powerful residue can continue to collect dirt after cleaning,
leading to the misconception that carpet cleaning can lead to the carpet getting “dirtier faster” after the cleaning.
The best method is truckmounted hot water extraction. When wet-shampoo chemistry standards converted from coconut oil soaps to synthetic detergents as a base,
the shampoos dried to a powder, and loosened dirt would attach to the powder components, requiring vacuuming by the consumer the day after cleaning.
5.Hot Water Extraction
Although there is an actual steam cleaning industrial process, in the context of carpet cleaning, “steam cleaning” is,
in fact, hot water soil extraction cleaning, which is professionally known as HWE.
The hot water soil extraction cleaning method uses equipment that sprays heated water, sometimes with added cleaning chemicals, on the carpet.
Simultaneously, the water is vacuumed up, along with any dislodged and dissolved dirt. Many carpet manufacturers recommend professional hot water extraction as
the most effective carpet cleaning method which also provides a deeper clean.
Actual steam could damage man-made carpet fibers and change the characteristics as they are usually set using heat.
Natural fiber carpets such as wool can shrink, velvet-piled carpets and Berber carpets will become fuzzy which is known as pile burst.
Hot water extraction equipment may be a portable unit that plugs into an electrical outlet, or a truck mount carpet cleaner requiring long hoses from the truck or trailer.
Truck-mounted equipment may be used where electricity is unavailable, but may be unsuited to premises distant from a driveway or road, and require hoses to pass through windows to reach the upper floors of a building. The hoses needed for truck-mount and professional portable carpet cleaning may present a trip hazard, and allow pets or children to escape through doors left ajar. Heated or air conditioned air can also be wasted when doors are left open for hoses. Truck-mounted carpet cleaning equipment minimizes the noise in the room being cleaned, but may cause noise and air pollution offensive to neighbors, and could violate anti-idling bylaws in some jurisdictions. However, truck-mounted cleaning is much faster than portable equipment, and the extra heat will dissolve more spots and stains, and more vacuum suction power will reduce drying times.
A common process of hot water extraction begins with preconditioning.
Alkaline agents such as ammonia solution for synthetic carpets, or acidic solution (such as vinegar solution) for woollen carpets, are sprayed into the carpet,
then agitated with a grooming brush or an automatic scrubbing machine. Next, a pressurized manual or automatic cleaning tool (known as a wand)
passes over the surface to rinse out all pre-conditioner, residue, and particulates.
If an alkaline detergent is used on a woollen carpet, use of a mild acetic acid solution will restore neutral fiber pH. The acidic rinse thus neutralizes the alkaline residues, and can contribute to softening cleaned fabrics.
The hot water extraction method is the preferred method of many carpet manufacturers as it removes more dust and abrasive particles resulting in
less wear and pile abrasion.
Extraction is, by far, the most important step in the hot water extraction process.
Since the hot-water extraction method uses much more water than other methods like bonnet or shampoo cleaning, proper extraction and air flow
are critical to avoid drying issues such as mold growth & browning of wool fibres.
Drying time may also be decreased by extra use of fans, de-humidifiers, and/or outdoor ventilation.
Older surfaces, such as double jute-backed carpets and loose rugs with natural foundation yarns, could shrink after a wet treatment,
leading to suppositions that wet-cleaning could also remove wrinkles.
However, this notion is antiquated and this method could also occasionally tear seams or uproot strips.
Newer carpets, such as with synthetic backing and foundation yarns, do not shrink, and they smooth easily; in such carpets,
wrinkles indicate an underlying problem, such as delamination where the secondary backing becomes unstuck from the primary backing,
that may need a certified carpet inspector to determine.
Wet-cleaning systems naturally require drying time, which may lead to concerns about very slow drying,
the risk of soiling returning during drying as the moisture evaporates bringing the soils from deeper within the pile to the surface,
as well as odors, bacteria, fungi, molds, and mildews.
Carpet cleaning specialists try to find a balance between rapid drying (attributable to lower flow rate through the cleaning jets of a spray system)
and the need to remove the most soil (attributable to higher flow rate).
Pretreatments similar to those in dry-cleaning and “very low moisture” systems are employed, but require a longer dwell time of 15 to 20 minutes,
because of lower amounts of carpet agitation. Ideal pretreatments should rinse easily and leave dry, powdery,
or crystalline residue that can be flushed without contributing to re-soiling.