SYSTEM FOR METERING PARTICULATE MATERIAL

• US 3,804,303 A
• Filed: 09/20/1972
• Issued: 04/16/1974
• Est. Priority Date: 03/05/1971
• Status: Expired due to Term

• Current Assignee: ESM International Inc.
• Original Assignee: Arthur L. Fassauer
• Inventors: Fassauer, Arthur L.
• Primary Examiner(s): Tollberg, Stanley H.
• Assistant Examiner(s): Martin, Larry
• Application Number:
  US05/290,648
• Time in Patent Office: 573 Days
• Field of Search: 222/193,195,216,226,227,228,239,236,240,242,241,330,333,405,178,319,353,411,412 259/7,8,180 239/680,681,687,222 214/17B
• US Class Current: 406/71
• CPC Class Codes: B01J 8/002 with a moving instrument
• CPC Class Codes: B65G 65/4836 and moving material over a stationary surface, e.g. sweep arms or wheels
• CPC Class Codes: B65G 69/20 Auxiliary treatments, e.g. aerating, heating, humidifying, deaerating, cooling, de-watering or drying, during loading or unloading; Loading or unloading in a fluid medium other than air
• CPC Class Codes: G01F 13/006 measuring volume in function of time

Abstract

A mass of particulate material stored in a hopper is bottom unloaded and passed through several stages of aeration and fluidization to condition the material and place it in a relatively uncompacted state. The material is conditioned with a minimum of vibration of the material mass so that the mass remains a homogenous mixture of densities and does not stratify into powdery and coarse materials. The conditioned material is fed to a distributor ring wherein it is further aerated and fluidized into an uncompacted state and moved in a uniform volumetric flow through an annular array of holes into a pneumatic conveyor. Becasue the material is placed in an uncompacted state while being maintained a homogenous mixture of densities, a very precise mass of material may be metered out as a linear function of the time of delivery. With the present system, preselected masses of material can be delivered with extremely high accuracy.

Claims

1. A particulate material metering process comprising:

maintaining a substantially constant quantity of particulate material in a metering zone defined by a substantially horizontally disposed support surface and a metering surface extending upwardly from the support surface to a metering edge;

forming a generally uniform mound of particulate material above the support surface and engaging the metering surface, said mound having an upper surface extending in accordance with the natural angle of repose of the particulate material to a level in the plane of the metering surface with is above the metering edge; and

moving the mound of particulate material with a rotating blade radially outward along the metering surface so that particulate material from the top of the mound flows over the metering edge under the action of gravity.

2. A particulate material metering process as set forth in claim 1 which also includes the additional step of:

aerating and fluidizing the particulate material to place it in a state of low compaction prior to maintaining the material in the metering zone.

3. A particulate material metering process as set forth in claim 1 which includes the additional step of:

storing a quantity of the material to be metered in a hopper; and

feeding material from the storage hopper into the metering zone.

4. A particulate material metering process as set forth in claim 1 which includes the additional step of:

catching the particulate material which flows over the metering edge in a collection hopper.

5. A particulate material metering process as set forth in claim 4 which includes the additional steps of:

entraining the particulate material caught in the collection hopper in a flow of air; and

transferring the entrained particulate material to a remote location.

6. A method for accurately metering a defined mass of particulate material into a collecting hopper, comprising:

aerating and fluidizing the particulate material while simultaneously minimizing vibration thereof to place said material in an unstratified state of low compaction;

feeding said material into a metering zone;

aerating and fluidizing said material within said metering zone and moving said material radially outward by a barrier member, simultaneously forming a unformly compacted mound of particulate material having a fixed geometric configuration characterized by the natural angle of repose of the particulAte material;

defining a fractional volume of said mound containing a predetermined mass of material; and

allowing said fractional volume of material to flow by gravitational action from the top of said mound and thereby metering a defined mass of material into said collecting hopper.

7. A method for accurately metering a defined mass of particulate material into a collecting hopper as set forth in claim 6 wherein the first aerating and fluidizing step includes:

passing the particulate material through an apertured plate; and

collecting the particulate material passing through the apertures in the plate in a conical metering hopper.

8. A method for accurately metering a defined mass of particulate material into a collecting hopper as set forth in claim 7 wherein the feeding step includes:

gently agitating the collected particulate material in a narrow region adjacent the conical wall of the metering hopper to bottom unload material from the metering hopper into the metering zone.

9. A method for accurately metering a defined mass of particulate material into a collecting hopper as set forth in claim 6 wherein the forming step includes:

permitting particulate material to flow freely over and around said moving barrier member and leaving a mound of material having a fixed geometric configuration ahead of said moving barrier.

10. A method for accurately metering a defined mass of particulate material into a collecting hopper as set forth in claim 9 wherein said defining step includes:

moving the barrier member adjacent to a vertically extending metering surface having a metering edge at the top to form a mound of particulate material characterized by a natural angle of repose extending to a level on the metering surface above the metering edge, said frictional volume of said mound being that material lying above a surface parallel to the natural angle of repose and passing through the metering edge.

11. A process for metering particulate material including the steps of:

bottom unloading particulate material from a hopper into a particulate material aeration and fluidization zone;

aerating and fluidizing the particulate material within the aeration and fluidization zone so that the mass of particulate material per unit of volume is substantially constant throughout the aeration and fluidization zone;

bottom unloading particulate material out of the aeration and fluidization zone into a metering zone comprising a support surface and a metering surface extending upwardly from the support surface and having a plurality of particulate material discharge ports formed through it at a predetermined height above the support surface;

forming a mound of particulate material on the support surface in the metering zone characterized by an upper surface extending at the natural angle of repose of the particulate material to a level on the metering surface which is above the particulate material discharge ports formed therein; and

moving the mound of particulate material radially outward by a rotating blade around the metering surface in the metering zone so that particulate material from the top of the mound continuously flows out through the particulate material discharge ports in the metering surface under the action of gravity.

12. A process for metering particulate material as set forth in claim 11 wherein the aeration and fluidization step includes:

passing the particulate material, in free fall, through an open space;

catching the falling particulate material within a conical metering hopper;

gently agitating the particulate material in the region adjacent to the inner wall of the metering hopper.

13. A process for metering particulate material as set forth in claim 12 wherein the agitation step includes:

moving an elongate flexible member about the surface of the inner wall of the metering hopper.

14. A process for metering particulate material as set forth in claim 11 which Also includes the steps of:

catching the particulate material flowing out through the discharge ports in a collection hopper;

entraining the particulate material caught in the collection hopper in a flow of air;

transporting the entrained particulate material to a remote location.

15. A process for metering particulate material as set forth in claim 11 wherein the forming step includes:

allowing all particulate material in excess of a predetermined quantity to flow from the mound onto the support surface under the action of gravity.

16. A process for metering particulate material comprising:

bottom feeding particulate material from a hopper into a first aeration and fluidization zone comprising a substantially horizontally disposed plate having a plurality of outlet holes formed therethrough;

rotating a first thin, elongate member in the first aeration and fluidization zone at a level just above the plate to aerate and agitate the particulate material therein and to feed the material out of the first aeration and fluidization zone through the holes in the plate;

receiving particulate material from the first aeration and fluidization zone in a second aeration and fluidization zone comprising an upper outwardly and downwardly tapered conical member and a lower inwardly and downwardly tapered conical member surrounding the lower end of the upper conical member to define an annular opening therebetween;

aerating and fluidizing the particulate material in the second aeration and fluidization chamber by rotating a second thin, elongate member in the second chamber along a path extending adjacent to the inner surface of the lower conical member;

receiving particulate material from the second aeration and fluidization chamber in a metering chamber comprising a substantially horizontal support member and a metering wall extending upwardly from the support member and having a plurality of metering holes formed therethrough;

rotating a distributor blade comprising at least one arm extending outwardly over the support surface to a point adjacent the metering wall and then upwardly adjacent the wall to aerate and fluidize the particulate material in the metering chamber and to form a radially outwardly traveling mound of particulate material characterized by an upper surface extending at the natural angle of repose of the particulate material to a point on the metering wall above the level of the metering holes therein, whereby particulate material from the mound flows from the top of the traveling mound through the metering holes in the metering wall of the metering chamber under the action of gravity as the mound moves along the metering wall ahead of the traveling arm.

17. A process for metering particulate material as set forth in claim 16 wherein said first and second thin elongate members and said distributor blade are all rotated in unison.

18. A process for metering particulate material as set forth in claim 16 which includes the additional step of:

passing the particulate material, in free fall, through an open space after the material is fed through the holes in the plate and before the material is received into the second aeration and fluidization zone.

19. A process for metering particulate material as set forth in claim 16 which includes the additional step of:

bottom unloading particulate material through the annular opening in the lower conical member into the metering chamber.

20. A process for metering particulate material as set forth in claim 16 which includes the additional steps of:

catching the particulate material flowing out through the metering holes in a collection hopper;

entraining the particulate material caught in the collection hopper in a flow of gas;

transporting the entrained particulate material to a remote location.

21. A metering system for particulate materials comprising:

a substantially horizontally disposed particulate material support surface;

means for maintaining a generally constant level of particulate material on said support surface;

a metering surface extending along and upwardly from the support surface to a metering edge;

a distributor blade including portions extending horizontally adjacent to the support surface and upwardly adjacent to the metering surface said distributor blade portions further including means which contact the particulate material; and

means for moving the distributor blade along the metering surface moving a mound of particulate material radially outward, said material having an upper surface extending at the natural angle of repose of the particulate material through points in the plane of the metering surface which are above the metering edge so that particulate material from the top of the mound flows over the metering edge under the action of gravity.

22. A metering system for particulate materials as set forth in claim 21 wherein the particulate material support surface is defined by passage of the bottom edge of the horizontally extending portion of the distributor blade along the upper surface of a quantity of stationary particulate material.

23. A metering system for particulate material as set forth in claim 21 wherein:

the material support surface is substantially circular, the metering surface is cylindrical and the metering edge comprises the lower edges of an annular array of port holes formed through the metering surface a preselected height above the support surface.

24. A metering system as set forth in claim 23 wherein the lower outside surfaces adjacent to the port holes are beveled to form sharp lower edges on the port holes to prevent the accumulation of particulate material therein.

25. A metering system as set forth in claim 21 wherein the moving means includes:

a motor mounted below the material support surface and having a drive shaft extending up through the support surface; and

means for fixing the distributor blade to the drive shaft of the motor for rotation therewith.

26. A volumetric system for particulate materials comprising:

a circular, substantially horizontally disposed particulate material support surface;

means for maintaining a generally constant level of particulate material on said support surface;

a cylindrical metering surface extending around and upwardly from the support surface and having a plurality of apertures formed through it;

a distributor blade having at least one arm extending outwardly above the support surface and then upwardly adjacent the metering surface said distributor blade having means which contact tha particulate material; and

means for rotating the distributor blade and thereby radially moving a mound of particulate material along the metering surface so that particulate material from the mound flows from the upper portion of the mound out through the apertures in the metering surface under the action of gravity.

27. A volumetric metering system for particulate materials as set forth in claim 26 wherein the apertures through the metering surface are formed with sharp lower edges.

28. A volumetric metering system for particulate materials as set forth in claim 26 wherein:

the means on the distributor blade include air-foil like leading edges and a flat vertically extending trailing surface to aerate and fluidize particulate material located above the support surface as the blade is rotated.

29. A volumetric metering system for particulate material as set forth in claim 26 wherein each arm of the distributor blade comprises:

a circular rod formed to extend outwardly above the support surface, upwardly adjacent the metering surfaces and inwardly above, parallel to, and spaced from the outwardly extending portion thereof.

30. A volumetric metering system for particulate material as set forth in claim 26 which also includes:

means for aerating and fluidizing particulate material to be metered onto the Material support surface.

31. A volumetric metering system as set forth in claim 26 which also includes:

means for catching the particulate material flowing out through the apertures in the metering surface;

means for entraining the caught particulate material in a flow of gas; and

means for transporting the entrained particulate material to a remote location.

32. A system for metering particulate material, comprising:

a storage hopper for containing a mass of said material, said hopper having a bottom opening therein;

a pressure release plate mounted in and closing the bottom opening in said hopper, said plate having a plurality of downwardly and outwardly beveled holes therein;

an upper orb-sweep rotatably mounted above said pressure release plate;

an upper orb-sweep wire fixed to said upper orb-sweep and extending radially outward adjacent the upper surface of said plate;

a conical metering hopper located below said pressure release plate for collecting material passing through the holes in said plate, the wall of said hopper tapering downwardly and inwardly to define a central feeding opening at the bottom thereof;

a distributor ring located beneath the central feeding opening in said metering hopper, said distributor ring comprising a circular substantially horizontally disposed particulate material support surface and a cylindrical metering surface extending around and upwardly from the support surface and having a plurality of port holes formed therethrough;

a distributor blade rotatably mounted with said distributor ring and having at least one arm extending outwardly above the support surface and then upwardly adjacent the metering surface;

a lower orb-sweep wire fixed to said distributor blade and extending up through the central feeding opening and parallel and adjacent to the inner surface of said metering hopper;

means for linking said distributor blade and said upper orb-sweep for conjoint rotation;

a collecting hopper located beneath said distributor ring;

means for rotating said distributor blade to (a) move said upper orb-sweep wire adjacent the upper surface of said pressure release plate to fluidize and bottom unload particulate material from said storage hopper through the holes in said pressure release plate and into said metering hopper, (b) move said lower orb sweep wire adjacent the inner surface of said metering hopper to fluidize and bottom unload particulate material through said central feeding opening into said distributor ring, and (c) rotate said distributor blade and move a mound of particulate material along the metering surface of said distributor ring to allow a predetermined fraction of the mound to flow, by gravitation action, through the port holes in the metering surface into said collecting hopper.

33. A system for metering particulate material as set forth in claim 32 which also includes:

a horizontally extending top pressure plate mounted above the upper orb-sweep for supporting a portion of the weight of the mass of particulate material thereabove to permit the orb-sweep to rotate freely.

34. A system for metering particulate material as set forth in claim 32 wherein said upper and lower orb-sweep wires are formed of a resilient flexible material.

35. A system for metering particulate material as set forth in claim 32 which also includes:

a material diverter cone mounted beneath said pressure relief plate, said cone having a downwardly and outwardly directed wall which extends beneath all of the holes in the pressure relief plate and defines an annular space between the outer periphery of said cone and the inner periphery of the metering hopper for the passage of particulate material into the metering hopper.

36. A system for metering particulate material as set forth in claim 32 wherein the distributor blade includes at least three arms equally spaced about the blade from one another.

37. A system for metering particulate matErial as set forth in claim 32 which also includes:

means for entraining the particulate material in the collection hopper in a moving flow of air; and

means for transporting the entrained particulate material to a remote location.

38. A system for metering particulate material as set forth in claim 32 wherein each arm of the distributor blade comprises:

an air-foil like leading edge to get beneath particulate material and pass the material across the upper surface thereof as the arm is moved;

a flat vertically extending trailing edge to permit particulate material passing across the surface of the blade to fall freely back to the material support surface, thereby aerating and fluidizing the material, and a rounded fillet between the outwardly and upwardly extending portions for allowing a portion of the mound to flow over the arm and thereby form a mound having a fixed geometric shape.

39. A system for metering particulate material including:

means for bottom unloading particulate material from a hopper into a particulate material aeration and fluidization zone;

means for aerating and fluidizing the particulate material within the aeration and fluidization zone so that the mass of particulate material per unit of volume is substantially constant throughout the aeration and fluidization zone;

means for bottom unloading particulate material out of the aeration and fluidization zone into a metering zone comprising a support surface and a metering surface extending upwardly from the support surface and having a plurality of particulate material discharge ports formed through it at a predetermined height above the support surface;

means for forming a mound of particulate material on the support surface in the metering zone characterized by an upper surface extending at the natural angle of repose of the particulate material to a level on the metering surface which is above the particulate material discharge ports formed therein; and

means for radially moving the mound of particulate material outwardly around the metering surface in the metering zone so that particulate material from the upper portion of the mound continuously flows out through the particulate material discharge ports in the metering surface under the action of gravity.

40. A system for metering particulate material as set forth in claim 39 which also includes:

means for catching the particulate material flowing out through the discharge ports in a collection hopper;

means for entraining the particulate material caught in the collection hopper in a flow of air;

means for transporting the entrained particulate material to a remote location.