an industrial butterfly valve which incorporates a disc valve mounted upon a valve stem , the butterfly valve having a tubular housing , with a gasket lining the interior passageway through the housing , the gasket and tubular housing having apertures provided therethrough for pivotally mounting of the valve stem and its disc element , and a sleeve provided upon the valve stem and lining the gasket apertures to prevent leakage of any fluid material therethrough or from contacting and deteriorating the contiguous gasket .