US 4,228,822 AGranted

Stream throttle

AssigneeTechnovators, Inc.

InventorGlen W. Fisher

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Abstract

The stream throttle includes a movable closure member having an inclined upstream surface and a parabolic downstream surface, an orifice which is throttled by the downstream surface, and an inclined entry surface extending upstream from the orifice in spaced relation to the downstream surface. The entry and downstream surfaces provide a flow control zone which terminates adjacent the orifice. These surfaces, together with the upstream surface, maintain material flow toward and through the control zone uniform, with minimum velocity gradients. The parabolic downstream surface outline causes orifice area and hence flow capacity to vary on a linear basis during movement of the closure member with respect to the orifice. In another disclosed embodiment, the upstream surface is formed by a stationary diverter member within which the closure member is insertable for stop-start flow control. The stream throttle may be used to provide a mass flow variable orifice for linear volumetric control of particulate material flow rates.

Claims7

Dependent claims

Apparatus for controlling flow of particulate material through an orifice, which apparatus comprises means for forming a hopper surface extending upstream from said orifice, and a flow control assembly located adjacent said orifice, said flow control assembly including an upstream surface, said upstream surface having means for directing particulate material toward said hopper surface upstream from said orifice and control zone forming means for forming a flow control zone immediately above said orifice in which the rate of increase in velocity of particulate material flow is minimized as the particulate material approaches said orifice, said control zone forming means including a downstream surface connected to said upstream surface, said downstream surface formed as a surface of revolution having a parabolic vertical cross-section, said downstream surface curving away from said hopper surface in vertical cross-section while being spaced from said hopper surface and means mounting said flow control assembly relative to said hopper surface to cause said downstream surface to extend partially through said orifice for maintaining uniform flow of particulate material from said hopper surface toward said orifice with the particulate material making essentially continuous contact with said downstream surface to minimize the rate of increase in velocity of particulate material as the particulate material flows toward said orifice.

An apparatus including a discharge passageway for blended particulate materials, blending means for introducing segregated streams of said particulate materials into the discharge passageway and combining the particulate materials into a common stream in the passageway at a point of combination, the passageway having an elongated section of at least a minimum length and of substantially uniform cross-sectional area commencing at the point of combination and extending downstream from the point of combination, and means downstream of the elongated section for restricting the flow therethrough to a rate less than the combined maximum flow rates of the segregated streams to obtain a uniform movement of cross-sectional segments of the solids at the point of combination, said minimum length being greater than the distance between the restricting means and a critical point upstream of the restricting means at which the flow begins to be nonuniform across the elongated section, the improvement comprising:

means located downstream of the elongated section forming a hopper surface extending upstream from an orifice in communication with the elongated section, a member including a conical upper surface with a slope greater than the angle of repose of the solids and control zone forming means for forming a flow control zone immediately above said orifice in which the rate of increase in velocity of particulate material flow is minimized as the particulate material approaches said orifice, said control zone forming means including a lower surface having a parabolic vertical cross section, support means extending longitudinally through the discharge passageway and said restricting means for supporting said member with said upper surface facing upstream to direct particulate material toward said hopper surface upstream from said orifice, said lower surface facing downstream and extending through said orifice and spaced from said hopper surface such that particulate material will flow from said hopper surface under uniform flow conditions while the rate of increase in velocity of particulate material flow decreases as the particulate material approaches said orifice with essentially continuous contact of the particulate material with said lower surface, and adjustment means connected with said support means for causing said member to be moved with respect to said hopper surface and said orifice in a direction parallel to the longitudinal axis of the discharge passageway to selectively position said member at a plurality of positions with respect to said orifice in order to control the effective area of said orifice, said lower surface having a length sufficient to maintain at least a portion thereof in opposed relation with the hopper surface commencing at said orifice and continuing upstream to said hopper surface when said member is positioned at any of said plurality of positions.

Dependencies are inferred from the claim text.