new additions (OT) Autoclaves

A pressure cooker is basically an autoclave. When canning vegetables the heat and pressure destroy any pathogens. Autoclaving is used to sterilize instruments and medical devices. The instruments are usually enclosed in a porous package that allows the moisture into the package and keeps any contaminants out. The high pressure with moisture is designed to activate and destroy any bacterial spores that may be in the package. There is usually a heat activated strip in the tape on the package that changes from invisible to brown and says "sterile". Any device that could be damaged by heat such as a plastic catheter can be "cold sterilized" by ethylene oxide gas. This is not as effective as the heat/moisture method. Also used on medical waste to reduce the chances of spread of disease. Many medical devices are now sterilized by ionizing radiation, gamma particles, a radiation source is exposed next to cases of the products and hopefully "zaps" the DNA in any contaminants. Another use of autoclaves is to laminate layers of carbon fiber cloth to create composite aircraft and machine parts. The heat and pressure cause the bonding agents, such as epoxy, to bind the layers together. I think the B2 and F117 skins are created by this process. More than anyone wants to know about autoclaves. Mike McFadden