Abstract: A high temperature, high pressure chemical digestion vessel comprising an inner container which fits within an outer casement. Tapered walls of the inner container define an air gap which insulates against excessive heat transfer between the inner container and the outer casement during high temperature and pressure digestion. The container is provided with a vent. A replaceable, rupturable pressure release disk is provided having a predetermined rupture pressure for being sealingly interposed in covering relation to the vent to seal the container and thereby enclose a substance to be digested in the container. The disk ruptures and releases pressure within the container if pressure within the container reaches the predetermined rupture pressure. The pressure release disk comprises a flat sheet material. A seal cap is provided for holding the pressure release disk in sealing relation to the vent in the container.

Abstract: A rapid, microwave-based Kjeldahl digestion method wherein microwave energy is applied to an acid/sample mixture at the beginning of, and thereafter during the digestion. After the application of microwave energy is discontinued, the digestate is diluted by pulsed addition of water, followed by continuous addition of water. Dilution in this manner prevents a sudden surge in gas evolution, and eliminates the need for an intervening cooling step, thereby reducing processing time. Also provided is a method for fat separation from a fat-containing protein sample during the digestion.

Abstract: A microwave-based apparatus for rapid digestion of a sampel by a Kjeldahl method is provided which includes a reaction vessel surrounded by an insulator in the form of, for example, a cup. The reaction vessel is disposed in the internal chamber of a microwave system, which includes a wall having an aperture. A connector tube is slidably disposed in the aperture, wherein one end of the tube is connected to the mouth of the reaction vessel, and the other end is connected to a suction device external to the chamber. A biasing element is provided outside the chamber to assist in joining the slidable connector tube to the mouth of the vessel, yet enabling removal of the vessel from the chamber without detachment of the biasing element.

Abstract: A valve that opens and closes in response to changes 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 microwave-based apparatus useful for rapid digestion is provided. The apparatus includes a hollow tubular body having an end sealingly joined to a reaction vessel disposed within a microwave system. The end of the tubular body has grooves for the flow of air through the sealed tubular body/reaction vessel joint. A scrubber removes digestion off gases. Also provided is a rapid, microwave-based, Kjeldahl digestion method.

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: An improved stuffer box crimping apparatus of the type in which tow is fed into a rectangular cross-section crimping chamber off-set from the bite of a pair of feed rolls, the apparatus employing a crimping chamber wherein one wall is predominantly formed by a single doctor blade and an opposite wall is formed by a portion of the rotating surface of one of the cylindrical feed rolls of the feed roll pair, the doctor blade being pivotally mounted on the feed roll nearest the tip portion of the doctor blade. The cross-sectional area of the crimping chamber diminishes toward the exit portion thereof, whereby crimped filamentary material within the crimping chamber is subjected to both back pressure and a constant forwarding action by the rotating surface of the cylindrical feed roll. The pivotal mounting of the doctor blade provides precise clearance and allows the volume of the crimping chamber to adjust in accordance with tow variations.

Abstract: Ventilated thermoplastic polymer foam filter rods and the processes for their preparation. The ventilated thermoplastic polymer foam filter rods are characterized by the presence of at least some cells which are bridged by fibrils, the rod being surrounded by a high density skin structure having a discontinuity such as to produce a ventilation of at least 50%. Discontinuity in the skin structure may be produced by skin solvent etching, skin abraiding, skin perforating and skin cutting.