Autoclave Alternatives

Autoclaves are sterilizing vessels that use pressurized steam to eradicate microorganisms. They are used in laboratories or similar settings to prepare culture media, to sterilize medical or lab equipment and for decontaminating bio-hazardous waste material. Although autoclaves are the most widely used sterilization technique, there are other ways to achieve sterilization. Autoclaves are also used in aerospace applications to ensure a high-fiber volume in components -- there are alternatives to the autoclave in this field, too.

Gamma Irradiation

• With gamma irradiation, high-energy photons are emitted and disrupt electrons throughout an item. In living cells, this disruption causes damage to DNA and either kills an organism or makes reproduction impossible. This process of sterilization usually takes four to six hours to complete.

e-Beam

• E-beam, or electronic-beam sterilization, uses an electron-beam linear accelerator to concentrate electrons that are accelerated close to the speed of light. This produces very fast reactions in molecules on an item undergoing sterilization. A conveyor system moves items for sterilization under the e-beam at a pre-determined speed. One of the advantages of the e-beam technique is the fast sterilization rate.

Ethylene Oxide

• Ethylene oxide (ETO) sterilization involves placing objects needing sterilization into a chamber. Ethylene oxide gas is pumped in, permeates through any packaging and is then vacuumed out continuously. The entire process can take up to 14 days. Any packaging must be porous so the gas can sterilize any contained equipment.

Alternatives in Aeropsace Applications

• Structural composite components in aerospace applications require curing; this has traditionally been done with autoclaves. The high pressure in an autoclave forces pieces to have a high-fiber volume generally not seen in non-autoclave processes, but alternatives still exist and have their own strengths.

  Vacuum-assisted resin transfer molding (VARTM) includes a variety of resin-infusion processes that are commonly used in transportation, marine and infrastructure fields. With this process, fiber reinforcements and core materials are placed, dry, in a mold and vacuum-bagged. Liquid resin is then drawn through the fiber reinforcements by vacuum. The VARTM cure does not require high heat or pressure and it is lower-cost than an autoclave.

  Resin transfer molding (RTM) uses a more costly closed mold, usually metal. This process uses low-viscosity resins, which are mixed immediately before infusion, allowing for the use of fast-curing resin and a much faster cycle time than in autoclaves.

  A third alternative to autoclaves in the aerospace and related industries is oven curing. This alternative is promising for its lesser departure from traditional autoclave curing.