Abstract: The present invention provides an improved valve. This valve opens and closes in response to a change in the physical environment of the valve. This valve is particularly suited as a relief valve in a microwave system-based, closed vessel digestion procedure. This valve includes a pressure-deformable, resilient wall member having a fluid vent port, and an obstructing member that cooperates with the wall member to open and close the valve. Also provided is a lidded vessel employing this improved valve, an apparatus that includes a microwave system and this lidded vessel, and methods using this improved valve.

Abstract: A method of sizing thermoplastic foamed cigarette filter rods and apparatus therefore. The apparatus comprises a rotating drum member having a plurality of stationary heated block members mounted about the periphery thereof. The block members are positioned such that a specific gap is created through which the thermoplastic polymeric filter rods are rolled and compressed to a uniform circumference.

Abstract: An apparatus for controllably heating material directly and indirectly by microwave radiation comprises a chamber in which the material to be heated (often to dryness, as for analysis) is placed, a source of microwave radiation for radiating into materials in such chamber for controllably heating such a material, and a support for such material, which support comprises a matrix of microwave radiation-transmissive material and a particulate microwave absorptive material dispersed in such matric material, which microwave absorptive material has a Curie temperature, above which it becomes microwave transmissive, so as thereby to prevent excessive heating of the support and the material thereon which is to be controllably heated, and which matrix material is stable and form-retaining at the Curie temperature of the dispersed material.

Abstract: An apparatus for ashing materials which comprises a chamber, a source of microwave radiation for direction onto contents of the chamber, and in the chamber a support, such as a fused quartz pad or crucible, for the material to be ashed, and an ashing means of a stable microwave absorptive material, capable of being heated to high temperature by microwave radiation, such as a flat block of silicon carbide or a plurality of such blocks with openings therein to accommodate the crucible. The ashing means is in contact with the support for the material to be ashed and is capable of heating such support and such material to an ashing temperature.