There are several different types of carpet cleaning methods employed by professional cleaning services and this largely depends on the type of fabric or carpet fibers and also on specific needs of the home owners. One of the traditional yet versatile techniques employed by professionals is the carpet shampooing method.
The principle behind the shampoo method is that the carpet or rug is thoroughly cleaned using a foamy chemical which is then allowed to dry completely. As it dries, this residue pulls out all the embedded dirt and dust which has to be vacuumed off the next day. Since foaming is an important criterion of this technique, the reagent used for carpet shampooing must be able to generate high amounts of foam which will reduce the wetting of the carpet fibers. The ingredients present in the shampoo must also be able to generate stable foam and also dry out completely to a non-sticky residue. Professional cleaners also use a reagent which has high levels of lubricity so that the carpet fibers are not damaged while it is being brushed.
One of the most common ingredients that are found in all carpet cleaning shampoos is sodium lauryl sulfate or its many derivatives. Sodium lauryl sulfate has the property to generate high quantities of stable foam and hence is a regular ingredient in all kinds of shampoos and detergents. The only disadvantage of using cleaners with this chemical is that it leaves behind a sticky and soft residue which may cause resoiling of the carpet. To combat this problem, the cleaning reagent also contains an anti-soiling compound which acts like a resin and avoids resoiling of the fabric. Optical brighteners are also added to carpet shampoos to make it appear brighter and cleaner. These compounds trap the invisible ultraviolet light converting it into visible light making it appear brighter. But this can sometimes leave back a yellow cast which can be quite stubborn to remove.
Two different specialized equipments are employed in carpet cleaning process and these are rotary shampoo and cylindrical foam machines. In the former, ordinary rotary floor equipment is used for spraying the shampoo and then brushing the carpet. This method can lead to over wetting which can damage your carpet fibers. The cylindrical foam machine is more suitable as an air compressor is used to generate dry foam and a cylindrical brush for gentle but thorough cleaning of the carpets.