A vacuum mixer is a piece of equipment that allows the operator to mix compounds in vacuum conditions to limit excess air and prevent bubble formation. Such mixers are available from many companies for scientific research, food service and medical uses. These companies also supply replacement components and kits to extend the functionality of their equipment, such as different styles of mixer blade for different applications. It might be possible to rent a vacuum mixer for a particular application if purchasing one is not practical.
The vacuum mixer includes a central mixer drum with blade insert, designed to be fitted inside a casing to pump out air and create vacuum conditions. The level of vacuum and pressure can be adjustable by the operator for different applications. When in operation, the mixing blades rotate around a central assembly, thoroughly churning the contents of the mixer. It is possible to keep materials under vacuum throughout the process, if necessary.
One use for a vacuum mixer is in the preparation of cements, amalgam and other materials for medical applications. These cements can tend to fail if they contain air bubbles or are not completely mixed. The vacuum mixture prevents air bubble formation and thoroughly homogenizes the components, such as powders and alginates, to create a uniform, smooth mixture with an even texture. This will perform better than a hand-mixed preparation that might be prone to bubbles and other inclusions.
Mixer blades can operate in a variety of ways. Many designs include an outer squeegee blade to wipe down the sides of the mixer continuously. This forces material back into the mix to fully integrate it, and it prevents sticking. As the blade turn, the vacuum conditions will prevent the development of bubbles. The device might also have a degassing function to vent off any gases that form as a result of mixing reactions.
Many vacuum mixers adhere to rigid standards for medical and food equipment because they are often used in the production of products that humans will eat or come into close contact with. The devices can be fully broken down and sterilized, and they can come with components that can be replaced as needed to address concerns about contamination. Operators might also use test swabs to collect samples from the inside so they can check for bacteria and other sources of contamination. In some settings, the vacuum mixer might also be subject to inspection by government representatives who are responsible for setting and enforcing health codes.
