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Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning is often performed for aesthetic, hygienic, functional, safety, or environmental protection purposes. Cleaning occurs in many different contexts, and uses many different methods. Several occupations are devoted to cleaning.
Cleaning occurs in various commercial, domestic, personal, and environmental contexts, which differ in scale and requirements.
Cleaning is broadly achieved through mechanical action and/or chemical processes (usually solvation); many methods rely on a combination of mechanical and chemical action. Methods include:
Some items and materials require specialized cleaning techniques, due to their shape, size, location, or the material properties of the object and contaminants.
Several occupations involve cleaning, either in their entirety or among other duties.
Filtration is a physical separation process that separates solid matter and fluid from a mixture using a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding. The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles. Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms. In everyday usage the verb "strain" is more often used; for example, using a colander to drain cooking water from cooked pasta.
Dry cleaning is any cleaning process for clothing and textiles using a solvent other than water. Clothes are instead soaked in a water-free liquid solvent. Perchloroethylene is the most commonly used solvent, although alternative solvents such as hydrocarbons, and supercritical CO2 are also used.
An air purifier or air cleaner is a device which removes contaminants from the air in a room to improve indoor air quality. These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics, and at reducing or eliminating second-hand tobacco smoke.
Housekeeping is the management and routine support activities of running and maintaining an organized physical institution occupied or used by people, like a house, ship, hospital or factory, such as cleaning, tidying/organizing, cooking, shopping, and bill payment. These tasks may be performed by members of the household, or by persons hired for the purpose. This is a more broad role than a cleaner, who is focused only on the cleaning aspect. The term is also used to refer to the money allocated for such use. By extension, it may also refer to an office or a corporation, as well as the maintenance of computer storage systems.
Scrubber systems are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. An early application of a carbon dioxide scrubber was in the submarine the Ictíneo I, in 1859; a role for which they continue to be used today. Traditionally, the term "scrubber" has referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream. Recently, the term has also been used to describe systems that inject a dry reagent or slurry into a dirty exhaust stream to "wash out" acid gases. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases. Scrubbers can also be used for heat recovery from hot gases by flue-gas condensation. They are also used for the high flows in solar, PV, or LED processes.
Household chemicals are non-food chemicals that are commonly found and used in and around the average household. They are a type of consumer goods, designed particularly to assist cleaning, house and yard maintenance, cooking, pest control and general hygiene purposes, often stored in the kitchen or garage.
Downstream processing refers to the recovery and the purification of biosynthetic products, particularly pharmaceuticals, from natural sources such as animal tissue, plant tissue or fermentation broth, including the recycling of salvageable components as well as the proper treatment and disposal of waste. It is an essential step in the manufacture of pharmaceuticals such as antibiotics, hormones, antibodies and vaccines; antibodies and enzymes used in diagnostics; industrial enzymes; and natural fragrance and flavor compounds. Downstream processing is usually considered a specialized field in biochemical engineering, which is itself a specialization within chemical engineering. Many of the key technologies were developed by chemists and biologists for laboratory-scale separation of biological and synthetic products, whilst the role of biochemical and chemical engineers is to develop the technologies towards larger production capacities.
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
Ultrasonic cleaning is a process that uses ultrasound to agitate a fluid, with a cleaning effect. Ultrasonic cleaners come in a variety of sizes, from small desktop units with an internal volume of less than 0.5 litres (0.13 US gal), to large industrial units with volumes approaching 1,000 litres.
Infection prevention and control is the discipline concerned with preventing healthcare-associated infections; a practical rather than academic sub-discipline of epidemiology. In Northern Europe, infection prevention and control is expanded from healthcare into a component in public health, known as "infection protection". It is an essential part of the infrastructure of health care. Infection control and hospital epidemiology are akin to public health practice, practiced within the confines of a particular health-care delivery system rather than directed at society as a whole.
Carpet cleaning is performed to remove stains, dirt, debris, and allergens from carpets. Common methods include hot water extraction, dry-cleaning, and vacuuming.
Plasma cleaning is the removal of impurities and contaminants from surfaces through the use of an energetic plasma or dielectric barrier discharge (DBD) plasma created from gaseous species. Gases such as argon and oxygen, as well as mixtures such as air and hydrogen/nitrogen are used. The plasma is created by using high frequency voltages to ionise the low pressure gas, although atmospheric pressure plasmas are now also common.
The RCA clean is a standard set of wafer cleaning steps which need to be performed before high-temperature processing steps of silicon wafers in semiconductor manufacturing.
Parts cleaning is a step in various industrial processes, either as preparation for surface finishing or to safeguard delicate components. One such process, electroplating, is particularly sensitive to part cleanliness, as even thin layers of oil can hinder coating adhesion.
A cleaner, cleanser, cleaner or cleaning operative is a type of industrial or domestic worker who does the cleaning. A janitor, also known as a custodian, porter or caretaker, is a person who cleans and might also carry out maintenance and security duties. A similar position, but usually with more managerial duties and not including cleaning, is occupied by building superintendents in the United States and Canada and by site managers in schools in the United Kingdom.
Decontamination is the process of removing contaminants on an object or area, including chemicals, micro-organisms or radioactive substances. This may be achieved by chemical reaction, disinfection or physical removal. It refers to specific action taken to reduce the hazard posed by such contaminants, as opposed to general cleaning.
A biogas upgrader is a facility that is used to concentrate the methane in biogas to natural gas standards. The system removes carbon dioxide, hydrogen sulphide, water and contaminants from the biogas. One technique for doing this uses amine gas treating. This purified biogas is also called biomethane. It can be used interchangeably with natural gas.
A parts washer is a piece of equipment used to remove contaminants or debris, such as dirt, grime, carbon, oil, grease, metal chips, cutting fluids, mold release agents, ink, paint, and corrosion from workpieces. Parts washers are used in new manufacturing and remanufacturing processes; they are designed to clean, degrease and dry bulk loads of small or large parts in preparation for assembly, inspection, surface treatment, packaging and distribution. Parts washers may be as simple as the manual "sink-on-a-drum" common to many auto repair shops, or they may be very complex, multi-stage units with pass-through parts handling systems. Parts washers are essential in maintenance, repair and remanufacturing operations as well, from cleaning fasteners, nuts, bolts and screws to diesel engine blocks and related parts, rail bearings, wind turbine gears boxes and automotive assemblies.
Carbon dioxide cleaning (CO2 cleaning) comprises a family of methods for parts cleaning and sterilization, using carbon dioxide in its various phases. Due to being non-destructive, non-abrasive, and residue-free, it is often preferred for use on delicate surfaces. CO2 cleaning has found application in the aerospace, automotive, electronics, medical, and other industries. Carbon dioxide snow cleaning has been used to remove particles and organic residues from metals, polymers, ceramics, glasses, and other materials, and from surfaces including hard drives and optical surfaces.
Ice blasting is a form of non-abrasive blasting where frozen water particles are combined with compressed air and propelled towards a surface for cleaning purposes. Ice is one of several different media commonly used for blast cleaning. Another common method of non-abrasive blasting is dry ice blasting, which uses solid carbon dioxide as a blast media. Other forms of abrasive blasting use mediums such as sand, plastic beads, and baking soda.