Microwave digestion vessel of Teflon PFA material including a Teflon PFA vessel with a threaded cap and a threaded adjustable nut with a diaphragm. A valve assembly is formed by a U-shaped hole in the cap, a plunger extending downwardly from the adjustable nut into the U-shaped hole, and the diaphragm...http://www.google.es/patents/US4933529?utm_source=gb-gplus-sharePatente US4933529 - Microwave heating digestion vessel
