Abstract

A powdery material supply valve mechanism including a valve means disposed in front of a piston rod means in a longitudinally aligned relationship with each other, a valve housing means incorporating operatively the valve means and the piston rod means therein and a valve cylinder/piston means. This valve cylinder means is disposed shiftably in the longitudinal direction relative to the valve housing means, and a valve piston means disposed slidably in the bore of the cylinder means along the axis thereof to be urged operatively upon a valve seat of the valve housing means against the resilient force of a valve spring means under the effect of operating fluid pressure fed to the valve cylinder means, while the valve means is opened away from its valve seat with the resilient force of the valve spring means, when the operating fluid pressure is opened to the atmosphere. As the valve piston means stops abutting upon the end wall surface of the valve cylinder means, the current position of the cylinder end wall may determine a current degree of opening of the valve means. This position of the cylinder end wall may be set optionally with an adjustable longitudinal shifting of the valve cylinder means relative to the valve housing means.