Autoclave

An autoclave is a pressure chamber used to carry out industrial and scientific processes requiring elevated temperature and pressure different from ambient air pressure. Autoclaves are used in medical applications to perform sterilization and in the chemical industry to cure coatings and vulcanize rubber and for hydrothermal synthesis. Industrial autoclaves are used in industrial applications, especially regarding composites.Stovetop autoclaves, also known as pressure cookers—the simplest of autoclavesThe machine on the right is an autoclave used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal. (The machines on the left and in the middle are washing machines.)Horizontal high-capacity autoclave with cylindrical chamberIllustration of a cylindrical-chamber pass-through autoclave An autoclave is a pressure chamber used to carry out industrial and scientific processes requiring elevated temperature and pressure different from ambient air pressure. Autoclaves are used in medical applications to perform sterilization and in the chemical industry to cure coatings and vulcanize rubber and for hydrothermal synthesis. Industrial autoclaves are used in industrial applications, especially regarding composites. Many autoclaves are used to sterilize equipment and supplies by subjecting them to pressurized saturated steam at 121 °C (249 °F) for around 15-20 minutes depending on the size of the load and the contents The autoclave was invented by Charles Chamberland in 1884, although a precursor known as the steam digester was created by Denis Papin in 1679. The name comes from Greek auto-, ultimately meaning self, and Latin clavis meaning key, thus a self-locking device. Sterilization autoclaves are widely used in microbiology, medicine, podiatry, tattooing, body piercing, veterinary medicine, mycology, funerary practice, dentistry, and prosthetics fabrication. They vary in size and function depending on the media to be sterilized and are sometimes called retort in the chemical and food industries. Typical loads include laboratory glassware, other equipment and waste, surgical instruments, and medical waste. A notable recent and increasingly popular application of autoclaves is the pre-disposal treatment and sterilization of waste material, such as pathogenic hospital waste. Machines in this category largely operate under the same principles as conventional autoclaves in that they are able to neutralize potentially infectious agents by using pressurized steam and superheated water. A new generation of waste converters is capable of achieving the same effect without a pressure vessel to sterilize culture media, rubber material, gowns, dressings, gloves, etc. It is particularly useful for materials which cannot withstand the higher temperature of a hot air oven. Autoclaves are also widely used to cure composites and in the vulcanization of rubber. The high heat and pressure that autoclaves generate help to ensure that the best possible physical properties are repeatable. The aerospace industry and sparmakers (for sailboats in particular) have autoclaves well over 50 feet (15 m) long, some over 10 feet (3.0 m) wide. Other types of autoclaves are used to grow crystals under high temperatures and pressures. Synthetic quartz crystals used in the electronics industry are grown in autoclaves. Packing of parachutes for specialist applications may be performed under vacuum in an autoclave, which allows the chutes to be warmed and inserted into their packs at the smallest volume. It is very important to ensure that all of the trapped air is removed from the autoclave before activation, as trapped air is a very poor medium for achieving sterility. Steam at 134 °C can achieve a desired level of sterility in three minutes, in contrast to hot air at 160 °C, which can take two hours to achieve the same sterility. Methods of air removal include: