appropriate in describing what is being achieved. Most people judge a carpet’s cleanliness by its appearance and interim maintenance addresses this.
There are three techniques: bonnet cleaning, dry foam shampooing and absorbent powder cleaning. Collectively, these tend to be known as low moisture techniques, which are particularly desirable in locations where there is a constant flow of customers, as is the case in a hotel or casino.
Bonnet cleaning involves skimming over the surface of the carpet with a damp mop-like pad impregnated with cleaning agent and using a slow speed rotary machine. The procedure is speedy and therefore reasonably inexpensive, and it leaves the carpet quite dry. However, there is a significant risk, especially on carpets with a low-pile density, that pile burst and untwisting of the yarn will be accelerated. This results in a loss of pattern definition and a general fuzziness of the surface; for this reason, Couristan does not recommend bonnet cleaning.
Most dry foam shampooing techniques involve application of low moisture foam by means of a soft bristled brush rotating about a horizontal axis. There is less risk of pile burst from this technique and the carpet dries in a short period of time.
In absorbent powder cleaning, a fine powdered material impregnated with a mixture of detergents, solvents and water is scattered over the surface of the carpet and brushed in, typically with two contra rotating soft brushes mounted
about a horizontal axis. The detergent components loosen the dirt which combines with the absorbent material and is then vacuumed away. The carpet dries quite quickly and can be walked upon almost immediately. Manufacturers of this type of cleaning agent also state that their product is suitable for long-term maintenance programs, as well as being an interim procedure.
If interim maintenance is carried out, Couristan recommends that either the dry foam technique applied by a cylindrical brush, or the absorbent powder method, is followed.
PERIODIC MAINTENANCE
Periodic maintenance is the term applied to cleaning techniques intended to remove impacted soil, as well as achieving cosmetic cleaning.
In heavily trafficked areas where there is a considerable accumulation of impacted dirt, such as is the case in entrances, it is advisable before starting to clean, to thoroughly vacuum the area using a pile lifter (also known as a power brush). This is a twin-motor upright vacuum cleaner with one motor driving the brush and another providing the suction. The machine is operated more slowly than a conventional vacuum cleaner and
usually involves pulling it backwards over the carpet. The extra mechanical action and suction power that such machines provide help to remove dry impacted soil thereby making subsequent wet cleaning operations more successful. The two most common wet cleaning techniques are shampooing and hot water extraction. Shampooing usually makes use of a rotary brush machine (one which rotates about a vertical axis). The cleaning agent is held in a solution tank and is typically fed through the bristles of the brush as cleaning continues. This technique has two short-comings.
The first, is that being a rotary technique, it has a tendency, like bonnet cleaning, to burst the pile. Secondly, there is no suction, so the dirt is left behind in the carpet, along with the shampoo residues, which needs to
be vacuumed away when the carpet is dry; shampooing also leaves carpets very wet. Couristan does not recommend the use of rotary shampooing for their carpets.
Hot water extraction has over the past decades, become the preferred wet cleaning technique. The cleaning agent is sprayed onto the carpet and immediately extracted by an integral vacuum unit where it is collected in a recovery tank. This means that there is very short contact time between the carpet and the detergent. In order to increase contact time and thus obtain better detergency, the correct procedure is to pre-spray the carpet with a more concentrated detergent and allow a dwell time of approximately 10 minutes before the detergent is extracted. If the dwell time is too short, maximum benefit will not be achieved; if it is too long, the pre-spray will dry out and again cleaning performance will fail.
CORRECT CHOICE OF CLEANING AGENTS
Wool and wool rich carpet yarns are always dyed under acidic conditions. Nylon carpet yarns are often dyed under acidic conditions. If the cleaning agent causes the carpet to become alkaline, color bleeding is likely to result. This may not occur the first time that the wrong chemical is used, but the effect can be cumulative and bleeding may take place after the third or fourth cleaning.
Problems may also arise if the cleaning agent dries to a sticky residue. Such products are likely to promote rapid re-soiling. This means that once the carpet has been cleaned it will become much dirtier in appearance far more quickly.
To avoid either of these risks, Couristan requires that any carpet they produce be cleaned using WoolSafe approved chemicals. The WoolSafe Program is an internationally recognized certification program used to denote that the product has been tested for its suitability for use on wool (and also acid dyed nylon) carpets. Suitable products are identified by the logo illustrated below and a comprehensive list of more than 150 approved cleaning agents, stain removal products and ancillary products may be accessed at www.woolsafe.org.
