US3544170A - Pure fluid valving of suspended solids - Google Patents

Description

R. E. BowLEs PURE FLUID vALvIxG 0F 'SUSPENDED soLIDs Filed Jan. 24, 1969 Dec. 1, 1970 ATTORNEYj United States Patent O PURE FLUID VALVING OF SUSPENDED SOLIDS Romald E. Bowles, Silver Spring, Md., assgnor to Bowles Engineering Corporation, Silver Spring, Md., a corporation of Maryland Filed Jan. 24, 1969, Ser. No. 793,841 Int. Cl. B65g 53/04 U.S. Cl. 302-28 10 Claims ABSTRACT OF THE DISCLOSURE A fluid stream, laden with solid or liquid particulates, is selectively switched between two uid receiver passages by selectively introducing pressurized control uid tangentially about the stream periphery so as to introduce a vortical flow component in the otherwise axial flow. A pair of downstream receiver passages are concentrically disposed whereby substantially all of the flow, when axial, is received by the inner passage and substantially all of the flow, when a vortical component is introduced thereinto, is received by the outer receiving passage.

BACKGROUND OF THE INVENTION The present invention relates to an apparatus and method for controlling the conveyance of solid particulates, such as grain, sand, liquid droplets, etc., in a fluid stream. More particularly, the present invention relates to improved switching of such streams between two receivers using iluidic techniques.

It is known in the prior art to convey solid particulates from one location to another by immersing the particulates in a fluid stream. The stream can be directed to the desired location via fluid passages using appropriate valving action. When the particulate-laden stream arrives at the desired location, known separation techniques are employed to remove the particulates from the stream.

The advent o f fluidics has shown this technology to be particularly well suited for particulate transfer since fluidic valving requires no moving parts which might otherwise clog with particulates inadvertantly precipitating out of the particulate-laden stream. However, I have found that conventional fluidic switching elements have a crucial disadvantage in particulate handling. In conventional uidic switching elements, a power stream is deflected to one or another of two output passages by a control stream directed transversely to power stream ow. The problem has been that the particulates are not deflected along with the power stream fluid: This is due primarily to the greater density of the particulates relative to the fluid; the particulates thus have a greater inertia and therefore resist switching.

It is an object of the present invention to provide uidic techniques for switching particulate-laden uid streams, wherein effective switching of both the fluid and particulates is achieved.

It is another object of the present invention to provide a novel fluidic element which serves to effectively switch fluid streams laden with solid particulates.

SUMMARY OF THE INVENTION In accordance with the principles of the present invention, a. particulate-laden stream is caused to flow axially through a cylindrical supply tube. A vortical flow component is selectively introduced to the stream by means of control fluid injected tangentially about the stream periphery. Downstream of the control fluid injection location the tube flares outwardly and then assumes the configuration of an outer cylindrical receiving tube of greater diameter than the supply tube. A-n inner re- 3,544,170 Patented Dec. 1, 1970 ceiver tube, disposed concentrically within the outer receiver tube, is disposed to receive substantially all of the particulate-laden stream when solely axial. When a vortical ow component is introduced to the particulateladen stream, the fluid and particulates follow the contour of the outwardly flared supply tube and substantially all of the particulate-laden stream is received by the outer receiver tube.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIG. l is a diagrammatic illustration of a preferred embodiment of a fluidic valving element for particulateladen fluid streams in accordance with the principles of the present invention; and

FIG. 2 is a diagrammatic illustration of an alternate embodiment of a fluidic valving element for particulateladen fluid streams in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 of the accompanying drawings, there is illustrated a fluidic valving element 10 to which is applied a particulate-laden fluid stream to be selectively switched. Valving element 10 comprises a generally cylindrical supply tube 11 having an ingress end 12 to which the particulate-laden stream is applied. Flow straightening vanes 13 are located within supply tube 11, downstream of ingress end 12, and function to remove any incidental vorticity or spin in the particulate-laden stream, thereby assuring that flow is solely axial immediately downstream of the vanes.

A control flow passage 15 communicates with supply tube 11 via four orifices 17 located downstream of varies 13. A manifold 14 supplies pressurized control from flow passage 11 to all four of orifices 17 at substantially equal flow rates. 'Four co-planar and equally spaced orifices 17 are employed to assure that the control signal applied from passage 15 imparts symmetrical vortical flow components to the flow in supply tube 11. If only one orice 17 were employed the spin imparted to the particulate-laden stream by the control fluid would not be homogeneous. In many cases three orifices 17 are sufficient to assure symmetry. Passage 15 and orifices 17 are oriented with respect to supply tube 11 such that control fluid entering supply tube 11 via orifices 17 tries to follow a spiral path along the inner wall of supply tube 11. The control fluid is therefore introduced tangentially about the periphery of the particulate-laden stream, and, as a result of a momentum interchange between the streams, imparts a vortical flow component to the particulate-laden stream. The latter consequently responds to the controlfiow by converging from solely axial flow to a combined flow having both axial and vortical components. This transition in flow takes place in a mixing section 16 of the supply tube 11 immediately downstream of orifices 17.

Downstream of mixing section 16 the walls of supply tube 11 are outwardly rapidly forming a frusto-conical configured section 19. The walls of section 19 should diverge at an angle of at least 15 relative to the longitudinal axis of tube 11 in order to assure that wholly aXial ow of the particulate-laden stream does not attach to the walls in section 19. I have found a 30 divergence 'angle to be satisfactory, both to prevent axial flow attachment to the walls and to facilitate flow along these walls when the particulate-laden stream has vortical flow components. Downstream of section 19 the tube once Y again becomes generally cylindrical forming a receiver downstream of mixing section 16 of supply tube 11 and is concentrically disposed within receiver tube 21.' The diameter of receiver tube 23 is substantially the same (as the diameter of mixing section 16 of supply tube 11.

The location of the upstream end of receiver tube 23 relative to the upstream end of frusto-conical section 19 is determined by the intended operation of element 10, towit: in the absence of control iiuid flow in passage 15 the particulate-laden stream flow is solely axial and is received substantially in its entirety by receiver tube 23; when a vortical iiow component is introduced to the particulate-laden stream the flow follows a spiraling path along the contour of sections 16 and 19 and is received Vsubstantially in'its entirety by receiver tube 21. The ingress end of receiver tube 23 must therefore be suiciently close to the upstream end of Vsection 19 to receive substantially all of the particulate-laden stream when the ow is solely axial. On the other hand, the ingress end of receiver tube 23 must be sufliciently removed from the walls of section 19 and receiver tube 21 to permit reception of substantially all of the particulate-laden stream by receiver tube 21 'when the stream has bothV axial and vortical flow components.V In this respect, the slope of the tube walls in frusto-conicalsection 19 must be sufciently great to permit the axial only flow to separate from the walls of 19 and enter receiver 23 while corn-r bined axial-vortical flow will diverge due to spin and follow the wall contour in this section and be received by receiver tube 21.`

`If desired, and as illustrated in FIG. 1, flow received by the annular passage defined between the walls of tubes 21 and 23 may be dumped into a storage bin 25. Within the bin the particulates separate from the fluid due to gravitational forces and collect at the bottom of the bin while the fluid is vented from the top or sides. Receiver tube 23 extends`through'bin 25 to carry the particulateladen stream to some other location.

yIt is thus seen that by selectively controlling the application of controluidto passage 1,5, the particulateladen stream is selectively switched between receiver tubes A21 and 23. More importantly, the particulates-and fluid are switched together by this technique, rather than becoming separated because of their differing densities as was the case in the prior art. More particularly, when a vortical tlow component is introduced to the particulateladen stream, the particulates, having greater mass than the liuid, are ung to the outer periphery of the spinning stream by centrifugal forces, thereby assuring their reception by receiver tube 21. When the vortical flow; component is removed, the particulates are retained by the axially directed fluid, assuring their reception by receiver tube 23.

Referring now to FIG. 2 of the accompanying drawings, there is illustrated a modified version 30 of the valving element of FIG. 1. Like elements in elements and 30 are designated by like reference. numerals. The sole difference between elements y30 and 10 is the technique by which the vortical-flow component is selectively introduced to the particulate-laden stream.

In element 30, a control passage 33 is oriented to issue control fluid transversely of the particulate-laden stream rather than tangentially about the stream as is the case in element 10. The transversely directed control flow, due to momentum interchange withthe particulate-laden stream, Vcli-verts a portion of the latter to a diverter passage` Y 31 which has an ingress opening in communication with Y 4 flow in tube 11 at a locationrdownstream of the ingress opening of passage 31. The returned diverted flow is introduced tangentially about the periphery of the undiverted portion of the stream, thereby imparting a vortical flow component to the previously axially flowing stream. Reception of the solely axial stream by receiver tube 23 and of the combined axial-vortical stream by receiver tube 21 proceeds as described above for element 10 of FIG. 1.

In addition to a switching mode of operation, the described embodiments are capable of operating in an analog mode in which respective portions of the particulateladen iiow are proportionally directed to yboth receivers. This occurs when the vortical componentv of the stream liow is too low to cause all of stream to follow the walls of section 19, yet great enough to cause a portion of the stream to spin radially beyond the walls of receiver .tube 23. Naturally to effect this analog operational mode,

a low range of control fluid pressures is required.

While I have described and illustrated specific ernbodiments of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined inthe appended claims.

What is claimed is:

1. A tiuidic valving element for use in separating particulates from a particulate-laden stream, said valving element comprising:

a generally cylindrical supply tube;

means for flowing said particulate-laden stream axially within said supply tube; -lcontrol means for selectively introducing control uid into said supply tube to impart a vortical ow component to said particulate-laden stream; first receiver means for receiving substantially all of said particulate-laden stream from said supply tube when said particulate-laden stream has only axial flow components; and

second receiver means for receiving at least a portion of said particulate-laden stream from said supply tube when said particulate-laden stream has both axial and vortical flow components.

2. The valving element according to claim 1 wherein said control means comprises a control passage responsive to application of pressurized lluidthereto for issuing control fluid into said tube tangentially about the periphery of said particulate-laden stream.

3. The valving element according to claim 2 wherein said second receiver means receives substantially all of said particulate-laden stream when the pressure of said control uid exceeds a predetermined pressure.

4. The valving element according to claim 3 wherein said first receiver means comprises a lirstgenerally cylindrical receiver tube having a diameter substantially the same as the diameter of said supply tube and disposed coaxially with and downstream of said supply tube, and wherein said second receiver meanscomprises a second generally cylindrical receiver tube disposed concentrically about said first receiver tube.

5. The valving element according to claim 4 further comprising a generally frusto-conical section of tubing joining the downstream end of said supply tube and the upstream-end of said second receiver tube, the included angle formed between the walls of said frusto-conical section being at least 30. I6. The valving element according to claim 1 wherein said iirst receiver means comprises a first generally cylindrical receiver tube having a diameter substantially equal to the diameter of said supply tube and disposed coaxially with and downstream of said supply tube, and wherein said second receiver means comprises a second generally cylindrical receiver tube disposed concentrically about said first receiver tube, and further comprising a generally frusto-conical configured section of tubing joining the downstream end of said supply tube and the upstream end of said second receiver tube, the included angle formed Ibetween the walls of said frusto-conical section being at least 30.

7. The valving element according to claim 6 wherein said control means comprises:

a control passage communicating with said supply tube and responsive to application of pressurized uid thereto for issuing a control stream to detlect said particulate-laden stream, and a diverting passage disposed for receiving a portion of the particulateladen stream when deflected by said control'stream for issuing said portion into said tube downstream of said control passage and tangentially about the periphery of said particulate-laden stream.

8. The valving element according to claim 1 wherein said control means comprises:

a control passage communicating with said supply tube and responsive to application 0f pressurized' iluid thereto for issuing a control stream to deflect said particulate-laden stream, and a diverting passage 2 disposed for receiving a portion of the particulateladen stream when deected by said control stream for issuing said portion into said tube downstream of said control passage and tangentially about the periphery of said particulate-laden stream.

9. The valving element according to claim 1 wherein said means for owing includes ow straightening means within said supply tube and upstream of said control means for removing incidental vortical ow components from said particulate-laden stream.

10. The method for selectively switching an axially owing particulate-laden uid stream comprising the steps of:

selectively introducing control iiuid to said particulateladen stream to impart a vortical flow component therein;

receiving substantially all of said particulate-laden stream at a rst location only when said stream ows solely axially;

receiving substantially all of said particulate-laden uid stream at a second location only when said stream includes both axial and vortical ow components.

References Cited UNITED STATES PATENTS o 2,794,686 6/ 1957 Anselman et al. 302-24 3,226,165 12/ 1965 Oehlrich et al 302-59 3,458,237 7/1969 Noe 302-28 ANDRES H. NIELSEN, Primary Examiner U.S. Cl. X.R. 302-24, 59

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