Delivery and metering device for granulated and powdered materials

An apparatus for delivering and metering a flow of a granulated or powdered material from a collection facility to a processing stage, said device comprising:

• a metering screw means;
• a metering screw housing surrounding said metering screw means;
• a metering inlet in said metering screw housing;
• a delivery outlet in said metering screw housing having the lowest elevation at substantially the same elevation as the highest elevation of the inlet to said metering screw housing, said delivery outlet being disposed to pass the flow of the granulated or powdered material to the processing stage;
• means for presenting a continuous flow of the granulated or powdered material from said collection facility to said metering inlet such that said inlet is normally continuously filled with granulated or powdered material;
• means for driving and controlling the speed at which said metering screw means is driven thereby controlling the flow of material to the processing stage;
• and
• means for separating a portion of the flow of the granulated or powdered material not entering said metering inlet from the means for presenting a continuous flow.

A device for delivering and metering a flow of sand from a bin to a processing stage, said device comprising:

• twin main screws;
• means for driving said main screws;
• an inclined main screw housing surrounding said main screws;
• an inlet to said main screw housing adjacent said bin;
• an advance outlet to said main screw housing at a position elevated from said inlet;
• and
• a recycle outlet to said main screw housing at a position elevated from said advance outlet;
• means for metering the flow of sand from the bin to the processing stage comprising;
• a first metering screw;
• a second metering screw parallel to and intermeshed with said first metering screw, said first and second metering screws having identical pitch;
• means for driving said first and second metering screws in synchronous rotation;
• means for controlling the speed at which the first and second metering screws are driven;
• a metering screw housing surrounding both the first and second metering screw;
• a metering inlet of said metering screw housing in open communication with the advance outlet of said main screw housing;
• and
• a delivery outlet of said metering screw housing having a lowest elevation at substantially the same elevation as the highest elevation of the inlet to said metering screw, said delivery outlet being disposed to pass the flow of sand to the processing stage;
• and
• a trough running down the exterior of the main screw housing, beginning at the recycle outlet thereof and terminating at the bin;
• a frame;
• a rigid probe extension which projects into said means for returning to the collection facilities the sand expelled at the recycle outlet;
• a lever arm hingedly connected to the frame;
• a cable having one end connected to the distended end of the rigid probe extension and having the other end connected to the lever arm;
• a sensor arm disposed to engage said lever arm whereby variations of force exerted on said lever arm by said cable is transmitted to said sensor arm;
• a strain gauge connected to sensor arm to receive the movement thereof as an input and to generate an output signal that is a function thereof;
• and
• means for controlling the speed of the main screws responsive to the output signal of the strain gauge.

An apparatus for delivering and metering a flow of a granulated or powdered material from a collection facility to a processing stage, said device comprising:

• a metering screw means;
• a metering screw housing surrounding said metering screw means;
• a metering inlet in said metering screw housing;
• a delivery outlet in said metering screw housing having the lowest elevation at substantially the same elevation as the highest elevation of the inlet to said metering screw housing, said delivery outlet being disposed to pass the flow of the granulated or powdered material to the processing stage;
• means for presenting a continuous flow of the granulated or powdered material from said collection facility to said metering inlet comprising a main screw feeder for delivering granulated or powdered material from the collection facility to the inlet in said metering screw housing;
• means for driving and controlling the speed at which said metering screw means is driven thereby controlling the flow of material to the processing stage,
• a recycle outlet in said main screw feeder, the lowest point of said outlet being positioned substantially at or above the highest elevation of the inlet in said metering screw housing;
• and
• means for returning to the collection facility the granulated or powdered material expelled at the recycle outlet.

A device for delivering and metering a flow of a granulated or powdered material from a collection facility to a processing stage comprising:

• a main screw;
• means for driving said main screw;
• a main screw housing for receiving said main screw therein;
• an inlet to said main screw housing positionable to receive said granulated or powdered material at said collection facility;
• an advance outlet in said main screw housing at a position elevated from said inlet;
• and
• a recycle outlet in said main screw housing at a position elevated from said inlet and said advance outlet;
• means for metering the flow of the granulated or powdered material from the collection facility to the processing stage comprising:
• a metering screw means;
• means for controlling the speed at which said metering screw means is driven;
• a meter screw housing for receiving said metering screw means;
• a metering inlet of said metering screw housing in open communication with the advance outlet of said main screw housing;
• and
• a delivery outlet of said metering screw housing having a lowest elevation at substantially the same elevation as the highest elevation of the inlet to said metering screw means, said delivery outlet being disposed to pass the flow of the granulated or powdered material to the processing stage;
• and
• means for returning to the collection facility the granulated or powdered material expelled at the recycle outlet of the main screw housing.