Bottom closure for a chemical reactor

In a reaction vessel for holding solids and having a lower section including a conical part and a cylindrical outlet extending downwardly from said conical part for discharge of solids for said reaction vessel, and a closure member for closing off said outlet, said closure member having a cylindrical portion and a conical portion, the conical portion seating on said lower section conical part and said cylindrical portion locating in said cylindrical outlet when said closure member is in a closure position, there further being first seal means associated with said closure member and said lower section of the reaction vessel for effecting a seal of said outlet when said closure member is in closure position, said closure member being movable upwardly to an open position in said lower conical section for opening said outlet, the upward movement of said closure member being effective to destroy any bridge of solids as may exist in said lower section adjacent said outlet, the improvement which comprises

• a cap member loosely received in said lower section conical part in covering position over said closure member and resting on said lower section conical part when said closure member is in a closure position, said closure member during upward movement thereof engaging said cap member for lifting said cap member upwardly in said lower section conical part, and means operable to protect said first seal means from contact with solids when said closure member is moved to an open position, there being sufficient free space provided between said closure member and cap member such that said closure member during upward movement thereof does not engage with said cap member to lift same until said means for protecting said first seal means have become operable.