Rotary valve for controlling the flow of a solid particulate material

A rotary valve for controlling the flow of a solid particulate material comprising a hollow body having an internal circumferential surface provided with two diametrically opposed valve ports, a rotatable support disposed within said body, two diametrically opposed obturator elements carried by said rotatable support and cooperating with said valve ports, each obturator being movable radially relative to said support and relative to the other obturator element, and resilient means disposed between said support and each obturator element for urging each obturator element radially outwardly relative to said support and against said internal circumferential surface of the valve body, said body having internal end surfaces perpendicular to said circumferential surface, said support being in the form of said rectalinear frame having two sidewalls adjacent the internal end surfaces of said body, at least one of said sidewalls being fixed to a drive shaft, said frame having two additional sidewalls adjacent the internal circumferential surface of the body so that solid material will pass through the rectalinear frame when the valve is open, each obturator element having a bearing surface cooperating with a bearing surface on the support for the purpose of moving said obturator element circumferentially upon closure of the associated valve port with said bearing surfaces being inclined to each other in such a way that upon closure of the valve the support applies to each obturator element a direct radially outward force in order to augment the radial force of the resilient means.