This is the first of a three part article that will discuss the different types of carpet cleaning available on the market today. Our hope is that this will help you to choose the method that is right for you.
The basic methods of carpet cleaning are:
Let’s start with the carpet shampoo method.
Carpet Shampoo Method
Wet shampoo cleaning was widespread until about the 1970’s. The theory in the shampoo method is to generate lots of foam in the carpet by pushing the cleaning solution into the carpet by a machine that uses rotating brushes to work the solution into the fibers. The foam is then allowed to dry, attracting the soil to the resulting residue, and the resulting dirt-filled foam is removed by vacuuming.
Two primary types of machines are used for this process:
- Cylindrical Foam
- Rotary Shampoo
The Cylindrical Foam Shampoo machine uses an air compressor to create dry foam before the foam is applied to the carpet and the carpet is then agitated with a revolving cylindrical brush which combs the foam through carpet pile. This method will leave dirt trapped in the carpet pile, and 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.
Wet shampoo residues can be foamy or sticky, and 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.”
Shampoos can often simply bury the dirt, and because shampoos are actually very poor detergents they frequently also contain high levels of optical brighteners. These take invisible ultraviolet light and convert it to visible light, thus making the carpet appear cleaner and brighter than it really is, for a while. It will eventually give the carpet a yellow cast and the yellow cannot be removed.
Shampoo methods are considered inferior due to poor cleaning plus resoiling problems.