Los procesos de lavado incluyen el lavado (normalmente con agua que contiene detergentes u otros productos químicos), la agitación, el aclarado, el secado, el planchado y el plegado. El lavado se realiza a veces a una temperatura superior a la del ambiente para aumentar la actividad de los productos químicos utilizados y la solubilidad de las manchas, y las altas temperaturas matan los microorganismos que puedan estar presentes en el tejido. Sin embargo, se aconseja lavar el algodón a una temperatura más fría para evitar que se encoja. En el mercado hay muchos servicios profesionales de lavandería que ofrecen a diferentes precios.
La agitación ayuda a eliminar la suciedad que suelen movilizar los tensioactivos de entre las fibras, aunque, debido al pequeño tamaño de los poros de las fibras, el "núcleo estancado" de las propias fibras no ve prácticamente ningún flujo. No obstante, las fibras se limpian rápidamente por difusioforesis") transportando la suciedad hacia el agua limpia durante el proceso de aclarado.[14].
dry cleaning process
A dry cleaning machine is similar to a combination of a household washing machine and a clothes dryer. The garments are placed in the washing or extraction chamber (called "basket" or "drum"), which forms the core of the machine. The wash chamber contains a perforated horizontal drum that rotates within an outer casing. The housing contains the solvent, while the rotating drum contains the laundry load. The basket capacity ranges from about 10 to 40 kg (22 to 88 lb).
During the wash cycle, the chamber is filled about one-third full of solvent and begins to rotate, agitating the clothing. The temperature of the solvent is kept at 30 degrees Celsius (86 degrees Fahrenheit) or lower, as a higher temperature can damage it. During the wash cycle, the solvent in the chamber (commonly known as the "cage" or "tackle box") is passed through a filtration chamber and then returned to the "cage." This is known as a cycle and continues throughout the wash. The solvent is then removed and sent to a distillation unit consisting of a boiler and a condenser&action=edit&redlink=1 "Condenser (heat transfer) (not yet drafted)"). The condensed solvent is fed to a separator unit where the remaining water is separated from the solvent and then fed to the clean solvent tank. The ideal flow rate is approximately 8 liters of solvent per kilogram of garments per minute, depending on the size of the machine.
Clothing is also checked for foreign objects. Items such as plastic pens can dissolve in the solvent bath and damage textiles. Some textile dyes are "loose" and will release dye during solvent immersion. Fragile items, such as down quilts or rugs or tapestries with tassels, can be stored in a loose mesh bag. The density of perchlorethylene is about 1.7 g/cm at room temperature (70% heavier than water), and the sheer weight of the absorbed solvent can cause the textile to fail under normal force during the extraction cycle unless the mesh bag provides mechanical support.
Not all stains can be removed by dry cleaning. Items such as plastic pens can dissolve in a solvent bath, damaging textiles. Some textile dyes are "loose" and release dye during solvent immersion. Fragile items, such as down comforters, rugs, or tasseled hangings, can be placed in a loose mesh bag. The density of perchlorethylene is approximately 1.7 g/cm³ at room temperature (70% heavier than water), and the sheer weight of the absorbed solvent can cause the fabric to tear under the normal force of the extraction cycle, unless the mesh bag provides mechanical support.
A typical wash cycle lasts between 8 and 15 minutes, depending on the type of clothes and how dirty they are. During the first three minutes, solvent-soluble dirt dissolves in the perchlorethylene and loose, insoluble dirt falls away. Once the loose soil is loosened, it takes 10 to 12 minutes to remove insoluble soil from the garments. Machines that use hydrocarbon solvents require a wash cycle of at least 25 minutes because the dissolution rate of solvent-soluble soils is much slower. A Dry Cleaning Surfactant A dry cleaning "soap" can also be added.
At the end of the wash cycle, the machine begins a rinse cycle in which the load of laundry is rinsed with freshly distilled solvent dispensed from the solvent reservoir. This pure solvent rinse prevents discoloration caused by dirt particles being absorbed onto the surface of the garment from the "dirty" working solvent.
After the rinse cycle, the machine begins the extraction process, which recovers the solvent for reuse. Modern machines recover approximately 99.99% of the solvent used. The extraction cycle begins by emptying the solvent from the wash chamber and accelerating the basket to 350-450 rpm, which causes much of the solvent to be removed from the fabric. Until this point, cleaning is carried out at normal temperature, since the solvent is never heated in the dry cleaning process. When no more solvent can come out, the machine starts the drying cycle.
During the drying cycle, garments are tumbled in a stream of hot air (60-63°C/140-145°F) that circulates through the basket, evaporating any remaining solvent left after the spin cycle. The air temperature is controlled to prevent heat from damaging garments. The hot air leaving the machine then passes through a cooling unit where the solvent vapors are condensed and returned to the distilled solvent tank. Modern dry cleaning machines use a closed loop system in which refrigerated air is reheated and recirculated. In this way, high solvent recovery rates are achieved and air pollution is reduced. In the early days of dry cleaning, large quantities of perchlorethylene were vented into the atmosphere because it was considered cheap and believed to be harmless.
Once the drying cycle is complete, a deodorization (aeration) cycle cools the garments and removes further solvent residue by circulating fresh outside air over the garments and then through a vapor recovery filter made of activated carbon and polymer resins. After the airing cycle, the garments are clean and ready for pressing and finishing.