The utility model discloses a shield constructs machine knife dish spout, including valve body (2), fix fix the support frame (3) in valve body (2), the left end of fix the support frame (3) is provided with shrouding (1), and the right -hand member has set gradually spring (4) and has removed support frame (5), spring (4) establish at fix the support frame (3) and remove between support frame (5), fix the support frame (3) and removal support frame (5) are connected fixedly through bolt (6). The utility model discloses simple structure, the preparation is convenient, through the shrouding spring and liquid flow pressure 's of the exerting pressure down, the shrouding realizes the opening and the end -blocking of valve body end, fine solution the easy problem of being blockked up by the dregs of current blade disc spout, has reduced the blade disc and has blockked up the maintenance rate of bringing, improved the shield quick -witted working cycle of structure greatly, improved the construction progress, strengthened market competitiveness of enterprise.