WO2002051522A1

WO2002051522A1 - Particle loading anti-segregation distribution system

Info

Publication number: WO2002051522A1
Application number: PCT/US2001/050032
Authority: WO
Inventors: Aaron Fitzherbert
Original assignee: Materials Innovation, Inc.
Priority date: 2000-11-10
Filing date: 2001-11-09
Publication date: 2002-07-04

Abstract

An apparatus for providing a powder with a homogeneous distribution of particle sizes is provided. The apparatus includes an inlet to a cyclone generator section (109), a particulate material flow controller (117) located below the cyclone generator section, and a particulate material distributor (113) located below the particulate material flow controller, the particulate material distributor for distributing separated particulate material into a hopper. The apparatus also includes a filter (103) located above the cyclone generator section, and a fine particle return tube (123) leading to a recombining structure, wherein the fine particulate is combined with a combination powder and air stream, leading to the cyclone generator section.

Description

PARTICLE LOADING ANTI-SEGREGATION DISTRIBUTION SYSTEM

BACKGROUND OF THE INVENTION Technical Field: The present invention relates generally to a system for the

Description of Related Art: In the past, systems for loading and delivering powders and particulate materials have been designed using air or other fluids to transport the powders into various industrial processing equipment. These systems allowed the particles of which the powders were comprised to segregate according to size and density due to the actions of, for instance, gravity, resulting in non-uniform powders. Such non-uniform powders cause molds to fill unevenly and density throughout the finished part to vary from section to section. Such variances lead to unreliability in a part's mechanical properties. For example, in a process such as powder metallurgy where uniform distribution of powders is critical to the mechanical properties of parts formed by compacting the powder, non-uniform distribution of particles resulted in parts that possessed inferior mechanical properties. Therefore, it is desirable to eliminate segregation of the particles within a powder, and to provide powder with uniform particle size distribution.

SUMMARY OF THE INVENTION The present invention provides an apparatus and a method for providing a powder with a homogenous distribution of particle sizes. A' particulate material composed of particles wit a range of multiple sizes or densities is combined with a moving air stream which carries the particles through the apparatus creating a particle bearing air stream. Turbulence is induced into the particle bearing air stream, by generating a 5 cyclonic flow of the particulate material bearing air stream, in order to mix the particles of differing sizes or densities within the air stream,,' and in order to assure that a homogeneous distribution of particle sizes is conveyed to the particle distributor. Other means of turbulently mixing the particles, 0 including stationary mixing elements such as baffles, and apertures, and moving mixing elements, such as mixing blades, impellers, can be used to assure a homogeneous mixture of particle sizes and densities. For the purposes of this application, the terms cyclone and cyclonic flow are used 5 interchangeably, and refer to the flow of an air stream in which _! particles are suspended that moves in a spiraling manner, or in other words, moves simultaneously radially and axially. ! The apparatus includes a container with at least one intake I for a particulate material bearing air stream. The container 0 includes a first end through which the powder is delivered to a j hopper, and an opposing second end of the container through which particulate material is separated from excess air. A cyclone generator connected to the container and communicating with the container's interior, generates a cyclonic flow of 5 particle bearing air within the container. Communicating with j the cyclone generator is the intake for the particle bearing air I stream, through which the particulate material bearing air j stream is introduced. The turbulence of the cyclonic flow of ! the particle bearing air stream homogenizes the particle size distribution of the particles borne by the air stream. The homogenized cyclonic flow is directed toward the first end of the container. A portion of the particulate material escapes the flow of

1 'I

• i the air stream that is directed toward the first end of the ! ^!' ' container, and instead flows toward the second end of the

• container. This portion of the particulate material tends to be

5 the-..lighter, smaller, or less dense particles in the powder. A separator connected to, the second end of the container separates particulate material fϊom, the portion of the air stream flowing j away from the first -end of the container and toward the second end, and exhausts the excess separated air through a filter 10 which allows the particles to be suspended in the air stream. One aspect of the present invention includes an energy dissipater which reduces the kinetic energy of the air stream flowing to the second end of the container. In another aspect of the invention, the energy dissipater includes at least one 15 baffle affixed to the interior of the container between the intake and the second end of the container. The air flow retarder A particulate material recombiner connected to the particulate material intake for recycling particulate material I back to the cyclonic flow of particulate material air, 0 I communicates with the separator, and is connected to, and

I communicates with, the particulate material bearing air stream j intake.

J A particulate material distributor for distributing said j particulate material into a hopper is. connected to the first end 5 i of the container. The portion of the particulate material

! bearing air stream that is directed toward the first end passes ! through the distributor and is delivered into the hopper in a I uniform distribution pattern. Included in the distributor is a I particulate material flow controller for controlling the flow of 0 said particulate material into the particulate material , I distributor. The distributor is designed in such a manner so as i to: maintain the homogeneity of the particle size distribution. Another aspect of the invention is the method by which the

'I homogenous distribution of particle sizes is achieved. The ' particulate material of a powder is combined with an air stream to create a particle bearing air stream. The particle bearing

1 air..stream is caused to become a turbulent flow thereby mixing the particles of differing sizes uniformly within the flow.

Mixing the particles may be accomplished by various turbulence generating methods including cyclonic flow, such as causing the particle laden air stream to flow through apertures or baffles, or such as causing the particle laden air stream to be agitated , by additional jets of fluid, moving paddles, impellers The ' majority of particles is subsequently caused to separate from the air stream and caused to fall out of the flow

; ^: BRIEF DESCRIPTION OF THE FIGURES

Fig. 1. is a cross-sectional view of the invention. Fig. 2. is an exterior side view of an embodiment of the present invention.

Fig. 3. is a view of the separator of an embodiment of the present invention.

Fig. 4. is a side view of the exterior of the separator of I an embodiment of the present invention.

• Fig. 5. is an end view of an embodiment of the present _j invention with the distributor removed. i Fig. 6. is a view of the internal components of the j particulate material bearing air stream intake of an embodiment of the present invention.

1 Fig. 7. is a view of components used in the intake of an

I embodiment of the present invention. ■' Fig. 8. is a view of intake components of an embodiment of the present invention. Fig. 9. is a side view of the exterior of the particulate material flow control of an embodiment of the present invention.

"^'Fig. 10. is a perspective view of the exterior of the particulate material flow control of an embodiment of the 1 present invention.

Fig. 11. is a perspective view of the particulate material distributor of an embodiment of the present invention.

Fig. 12. is a top view of the particulate material distributor of an embodiment of the present invention showing the relationship of powder distribution apertures.

Fig. 13. shows an orientation of an embodiment of the present invention relative to a powder hopper. i Fig. 14. is a side view of an embodiment of the present

' invention. j Fig. 15. is a view of the exterior of the top cover of an i embodiment of the present invention. j Fig. 16. shows the arrangement of the flow retarding j baffles in the energy dissipater of an embodiment of the present invention. , Fig. 17. is a view of the exterior of the cyclone generator j of an embodiment of the present invention. I Fig. 18. is a view of the interior of the cyclone i generator, showing the relationship of the inlet, escaped ! particle recombiner and cyclonic flow director of an embodiment ' of the present invention.

Fig. 19. is a top view of the particulate material flow control hopper of an embodiment of the present invention.

Fig. 20. is a perspective view of a particle distributor, showing the relationship between the particle distributor cone, the apertures, and the distributor of an embodiment of the present invention. Fig . 21. shows the uniform distribution of powder provided s> by the distributor of an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

I. —,^'• A cross-sectional view of an embodiment of the present invention is illustrated in Fig. 1. Particulate material (not

I shown) , usually comApos'edAof particles of various sizes, and an j air stream are simultaneously introduced into the particle i loading anti-segregation system 101 at inlet 120, which is connected to cyclone generator 129. The cyclone generator 129 i is comprised of the cyclone generator section 109, the cyclonic

; flow director 110, and the tangential particle inlet 120. The

' particle bearing air stream (not shown) is homogenized and directed toward the particle flow control 112 by the cyclonic ; flow director 110. The particles fall out of the particle

I bearing air stream and fall into the particle flow control i hopper 117 and through the particle flow control orifice 125.

Due to friction, the particles tend to plug the particle flow control orifice 125 which results in a positive pressure within ^' the container 130.

I Subsequent to the particles passing through the particle

I flow control orifice 125, they enter the particle distributor j 113. Particle distributor 113 includes particle distributor

, cone 114, in which there is at least one distributor aperture J 127. The homogeneous mixture of particles forms a pile of powder around particle distributor cone 114, whereupon reaching the level of distributor cone aperture 127, distributor aperture

< 126, the particles flow through the apertures. ^'The particles j that flow through distributor aperture 126 are distributed radially within the associated powder hopper (not shown) , while

, the particles that flow through distributor cone aperture 127 i subsequently flow -through at least one bottom distributor aperture 128. Thus the particles are distributed evenly to the , powder hopper (not shown) rather than allowed to build up into a pile within the hopper.

Because the particle bearing air stream does not flow

¹ I, through the particle flow control orifice 125, due to

air stream flow away from the flow control hopper 117 and away from the cyclone generator 109, and instead flow toward the opposite end of the container. The air stream within the container is able to convey the powder away from the cyclone due to the relatively higher kinetic energy it possesses. In order to capture the escaped particulate material, the excess air stream is directed through energy dissipater 106, where the excess air stream is relieved of a portion of its kinetic energy by passing over at least one flow retarder 107, which in this view is a baffle. As kinetic energy is released from the excess

_I air stream, a portion of the escaped particles fall out of the excess air stream and fall toward the cyclone generator 109

! particle flow control hopper 117. _i The excess air stream continues past the energy dissipater

106 and into separator 105, consisting of at least one filter

103 and a screen 104 for preventing clogging of the filter. A i portion of the excess air stream passes out of particle loading anti-segregation distribution system 101 through screen 104 and filter 105, leaving the escaped particles which have not fallen j out of the excess air stream to be carried out through the top cover 102, through fine particle return tube 123, and to _] recombiner 121, which merges with inlet 120. The returned

! escaped particles are recombined with the air stream and particulate material in inlet 120, and introduced together into

<ι the container 130.

An embodiment of the system shown in fig. 1 includes at least one latch 108 to allow the system to be disassembled for inspection and maintenance. Upper grounding rod 124, lower grounding rod 118, andAnlet grounding rod 119 serve to dissipate static elect Ari^'cal charge via ground strap 122. Flange f"-, i^'.Α

115 is used to mount- particle loading anti-segregation distribution system 101 to powder hopper 116. io;

Claims

CLAIMS What is claimed is:

1. An apparatus for providing a powder with a homogenous distribution of particle sizes comprising: _ _t (a) a container with a first end through which said powder is delivered to a hopper, and an opposing second end at which i particulate material is separated from excess air;

(b) at least one intake which communicates with at least one turbulence generator, said turbulence generator communicating with the interior of said container and through which an air stream and particulate material are combined to ¹ create a particle bearing air stream, and through which said ' particle bearing air stream is introduced into said container; I „(c) a particulate material recombiner communicating with a separator at a first end, and with said intake at a second end, ¹ said separator for separating particulate material that has escaped from said particle bearing air stream and for exhausting ; excess separated air, said separator communicating with said ¹ second end of said container; ; (d) a particulate material distributor for distributing ' said particulate material into a hopper, said particulate i material distributor connected to said first end of said container; and

(e) a particulate material flow controller for controlling the flow of said particulate material into said particulate material distributor, said particulate material flow controller functionally associated with said particulate material distributor, i 2. The apparatus as in claim 1 wherein said container is j cylindrical and is oriented vertically.

I

3. The apparatus as in claim 1 wherein said turbulence

I _

I generator is a cyclone generator.

4. The apparatus of claim 1 wherein said particulate <ι material intake is a conduit. i

5. The apparatus of claim 1 wherein said recombiner is a conduit merging with said particulate material intake. --■,

6. The apparatus of claim 1 wherein said separator includes an energy dissipater.

7. The wherein said energy

dissipater is a con u t conta n ng at least one air stream flow retarder . ι

8. The apparatus of claim 5 wherein said air stream flow retarder is a baffle.

9. The apparatus of claim 4 wherein said separator includes at least one filter.

10. The apparatus of claim 1 wherein said particulate material flow controller includes at least one fixed aperture.

11. The apparatus of claim 1 wherein said particulate material flow controller includes an adjustable valve.

12. A method for providing a powder with a homogeneous distribution of particle sizes comprising: j (a) providing a source of an air stream; \ (b) providing particulate material;

! (c) combining said particulate material with said air i stream from said source to create a particle bearing air stream;

(d) creating a homogeneous mixture of generating a turbulent flow of said particle bearing air stream;

(e) extracting said particulate material from said turbulent flow of said particle bearing air stream and j subsequently causing said particulate material to be distributed i uniformly into a hopper; and ; (f) simultaneously capturing escaped particulate material j which has been conveyed away from said turbulent flow of said

! particle bearing air stream after said escaped particulate ; material has been combined with an excess air stream which flows in a ..direction counter to that of said turbulent flow of said particulate material bearing air stream, by separating said

: escaped particulate material from said excess air stream, and

I.

5 ' recombining said escaped particulate material with said particle

' bearing air stream before said particulate material bearing air stream is caused to become turbulent; and i (g) exhausting' said excess air.

13. The method of claim 12 wherein said turbulence is a

10 cyclone.

! 14. The method of claim 12 wherein said captured

> particulate material is reco bined by merging said captured particulate material with said particulate material at said intake.

15t 15. The method of claim 12 wherein said separation of said

I particulate material from said excess air stream includes dissipating energy from the excess air stream.

16. The method of claim 15 wherein said energy dissipation includes causing said air stream to pass at least one baffle.

,201 17. The method of claim 15 wherein said captured

, : particulate material is separated from said excess air by at

I least one filter.

I 18. The method of claim 12 wherein said flow of said

I particulate material into said distributor is fixed.

25, 19. The method of claim 12 wherein said flow of said particulate material into said distributor is variable.

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