Abstract: 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 extending downwardly into a recess in the adjustable nut. Pressure in the digestion vessel forces the plunger up against the diaphragm to move the plunger upwardly, subsequently releasing pressure through an exhaust hole in the cap.

Abstract: Microwave digestion vessel of Teflon PFA material including a Teflon PFA vessel with a threaded top and a Teflon PFA cap with internal threads for engaging the vessel threads. A valve assembly extends upwardly from a center portion of the cap and includes a valve seat, a valve ball internal thereto, a Teflon spring uniquely configured and a valve cap holding the spring and ball into the ball seat of the valve seat. An exhaust hole is provided out one side of the valve cap. The vessel includes a flange for encompassing a lower portion of the cap for pressure expansion protection. A ring with an adjoining flange is also provided for the cap to provide for pressure expansion protection. An alternative embodiment is illustrated with a side venting orifice with filtering, a dialed in spring pressure, and a spring cavity with an integral valving surface.