Valve plates for a sliding gate valve

Abstract From the Canadian patent

A pair of valve plates for a sliding gate valve each have a sliding surface which, in use, slide relative to one another and a discharge aperture which passes through the plate and opens onto the sliding surface. Each aperture is defined by two wail sections which extend perpendicular to the intended direction of relative displacement of the sliding surfaces and two wall sections which extend parallel to the said direction of displacement. This results in the length of the edges of the apertures which is exposed to the melt being reduced and any metal which solidifies between the plates being capable of being pushed into the apertures by relative movement of the plates.