Abstract: A vacuum concentrator uses microwave heating to enhance the rapid drying of a liquid specimen. Microwave heating without excessive arcing is made possible in a vacuum chamber by controlling the power of a microwave generator, by modifying antenna-like objects, and by interposing air in a direct path between opposing edges of microwave injection slots, while maintaining the vacuum condition in the vacuum chamber. This can be accomplished by using air filled plastic bosses passing through, and substantially filling the microwave injection slots. An alternate to the air filled bosses can be a non-metallic closure plate that excludes the microwave injection slots from the vacuum chamber, while allowing energy to be injected freely into the chamber. The microwave heating energy is absorbed by a vacuum chamber cover and dissipated to the atmosphere as heat.

Abstract: An adjustable slicing blade assembly comprises basically a slicing or spacer disk having a centrally disposed circular opening, a cylindrical flange extending from the under side of the spacer disk and surrounding the circular opening, and a rotatable shaft axially movable within the cylindrical flange and through the circular opening and having a slicing blade extending radially from its upper end. Appropriate mechanism is provided to locate the spacer disk and the shaft in a given position with respect to each other. Associated with the shaft and cooperating with such locating mechanism is an arrangement for maintaining such given position and also varying the same and thereby the separation between the slicing blade and the spacer disk.