Proportional controlled orifice for metering granular material

Abstract

Disclosed herein is a gate valve design with a proportionally controlled orifice area. The moving element of the gate is shaped to cooperate with a fixed element so that as the gate opens, the open orifice area changes geometrically.

What is claimed is: 
     
         1 . A system for metering particulate material, comprising:
 a container of dry particulate material, having a gravity-fed discharge;   a gate valve positioned in the discharge to control the flow of material from the container, the gate valve comprising a seat and at least one valve element movable out of the closed position to define a material feed orifice through which material is fed by gravity, the orifice being formed between the seat and valve element to vary in both length and width during at least a portion of the valve element movement.   
     
     
         2 . The system according to  claim 1 , wherein the orifice has a polygonal-shaped cross section area. 
     
     
         3 . The system according to  claim 1 , wherein the orifice area is quadrilateral shaped. 
     
     
         4 . The system according to  claim 1 , wherein the orifice area is square shaped 
     
     
         5 . The system according to  claim 1 , wherein the valve element has a triangular, cross-section shaped cutout area, extending through the valve element. 
     
     
         6 . The system according to  claim 1 , wherein the valve seat has a triangular-shaped opening. 
     
     
         7 . The system according to  claim 6 , wherein, the valve seat opening is in the shape of a right-angle triangle. 
     
     
         8 . The system according to  claim 1 , wherein, the valve element has a triangular-shaped opening. 
     
     
         9 . The system according to  claim 8 , wherein, the valve element opening is in the shape of a right-angle triangle. 
     
     
         10 . A system for metering particulate material, comprising:
 a container of dry particulate material having a gravity fed discharge; and   a gate valve position in the discharge to control the flow of material from the container, the gate valve comprising a seat and at least one movable valve element, at least one of the valve seat and valve element having a triangular-shaped opening, the valve element mounted to move out of a closed position where the triangular-shaped opening defines a material feed orifice through which material is fed by gravity.   
     
     
         11 . The system of  claim 10 , wherein both of the valve element and seat have triangular-shaped openings. 
     
     
         12 . The valve of  claim 10 , wherein the orifice is quadrilateral shaped. 
     
     
         13 . The valve of  claim 10 , wherein the triangular-shaped opening is a right-angled triangle. 
     
     
         14 . The valve of  claim 11 , wherein both triangular-shaped openings are right-angled triangles. 
     
     
         15 . A method for metering the flow of particulate material by gravity from a discharge opening in a container, comprising the steps of:
 positioning a sliding gate valve, comprising a seat and a valve element in the discharge opening;   selectively moving the valve with respect to the seat to form an orifice that varies in both length and width as the seat moves; and   flowing material through the orifice.   
     
     
         16 . The method of  claim 15 , wherein the gate valve positioning step comprises positioning a sliding gate valve with a triangular opening in at least one of the seat and valve element and wherein the opening forms at least a portion of the orifice. 
     
     
         17 . The method of  claim 15 , wherein the positioning step comprises positioning a sliding gate valve, having triangular openings formed in both the seat and valve element, and wherein the openings form at least a portion of the orifice. 
     
     
         18 . The method of  claim 15 , wherein the orifice form step comprises forming a polygonal-shaped opening. 
     
     
         19 . The method of  claim 15 , wherein the orifice form step comprises forming a quadrilateral-shaped opening. 
     
     
         20 . The method of  claim 15 , wherein the orifice form step comprises forming a square-shaped opening.