US2913110A - Closed section louver for material separating apparatus - Google Patents

Description

Nov. '17, 1959 R. E. ROGERS 1 CLOSED SECTION LOWER FOR MATERIAL SEPARATING APPARATUS Filed May 13, 1955 v INVEN'fOR R0554? fl/Poangs TORNEYST CLOSED SECTION LOUVER FOR MATERIAL SEPARATIN G APPARATUS Robert E. Rogers, Sausalito, Califi, assignor to Harvestaire, Inc., Oakland, Calif., a corporation of California 7 Application May '13, 1955, Serial No. 508,031

7 Claims. 01409-144 This invention relates to material separating apparatus in which particles of entrained material in a fluid carrier are segregated by virtue of differences in the unit mass weights of the respective particles; and more. particularly, the present invention is directed towards a louver attachment for use in a material separating charnber designed for segregating materials of very slight density differentials.

- In my copending application, Serial. No. 508,189, filed May 13, 1955, there is disclosed an open section type of louverin which an unobstructed vertical passage is provided between adjacent vanes of the louver. This is clearly distinguishable from a closed section type of louver in which there is a lateral overlapping of the vanes, this latter type of construction being generally disclosed in United States Letters Patent 2,638,181, 2,638,218 and 2,638,219. These louvers are provided in connection with separating equipment adapted to receive a continuous flow of fluid having material particles entrained therein, such flow and material being subjected in a conical separating chamber to various forces whereby selected components (namely the heavier values) are allowed to gravitally descend through the louver and out of the separating chamber, while the remaining mixture of rejected particles (tailings) and the carrier fluid are arrested from further gravital movement by the louver and are then caused to move upwardly and be discharged out of the chamber. While the louver construction disclosed in said patents as well asin my copending application areall designed for the same general purpose, ithas been found that where there is a very slight densitydifferential between the groups of particles to be separated, an open section louver is clearly impractical, as there is a tendency for even the lighter density tailings to pass between the vanes of the louver and become undesirably intermingled with the grain values. Likewise, although the louvers disclosed in the above identified patents, owned by a common assignee with the instant application, are .of the closed section type, it has been found difficult to adequately control the mechanism so that only the grain or desired values pass downwardly through the louver and the lighter or less dense materials pass upwardly for discharge, without some intermingling of the'- if:

heavierand lighter density particles. It is a principal object of the present invention to' provide material separating apparatus in which a separating chamber is utilized having a louver construction, includ ing a plurality of vanes, positioned so as to permit separation of particles of material having very small density differentials.

Another object of thisinvention is to provide separa tion equipment of the character described in which the less dense materials, even though initially passing downwardly and partially through the louver, will be caused grainror other valued par- .wallss, and a lower axially aligned discharge opening s i 2 construction of the character described including a central imperforate baflle portion and a plurality of uniquely shaped and arranged vanes, with alternate vanes having different forms and shapes than the other vanes of the louver. 1

The invention possesses other objects and features of advantage, some of which, with the foregoing, will'be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming'part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawing:

Figurel is a side elevational view of a material separator provided with the louver of the present invention.

Figure 2 is an'enlarged elevational view of the louver construction.

Figure 3 is a top plan view of the construction shown in Figure 2.

Figure 4 is an end view of several of the louver vanes, taken substantially in the plane indicated by line 44 of Figure 3, but with the vanes shown in parallel relationship rather than'radial relationship, for purpose of clarity in the drawing and a better understanding of the constructional details.

As hereinabove mentioned, the apparatus of the present invention has been particularly designed for the separation'of groups of particles of material in a carrier fluid,

in which such particles have relatively low density difdensity differential, to have the tailings pass out with the values, or the grain values pass out with the tailings. This is obviously an undesirable result, and by means-of the apparatus presently to be described, it has been found that effective and eflicient separation may be effected although possibly on a somewhat slower scale than when using an open section louver construction as shown in the above identified patent application. g

"The louver of the present invention is adapted to be used in cooperation with a separator 6, having a tangential inlet 7, downwardly sloping conically formed side 9. Material carried in a carrier stream, such as air, is introduced tangentially into the inlet 7 through a conduit 12 'operatively associated with -a blower or threshing fan 13. In other words, the fan 13 is arranged to direct a I flow of fluid and entrained material in which the density fan 17, the duct enteringthe separatorfrom the top there- 2, no further explanation as to details of construction or opgroups are intermingled, into the separator 6 in which it is acted uponby centrifugal and gravit-al forces to cause'a descen'sion of the entrained material of both lighter and heavier unit mass weights. As will be hereinafter described in detail, the heavier unit -mass weightsare adapted to be discharged-for collection through the opening-9 while the lighter components of the entrained material are adapted to be discharged through an axially extending "suction duct 16 connected to a suitable suction of and with'the throat of the suction duct 16 being axially spaced from the opening 9. The foregoing typeofcon-- struction is found in the above identifiedpatents as well as in other more conventional separating equipment and erationis deemed necessary. As the material is hurled around in the separator, centrifugal force will cause the particles to engageand move. along thednner peripheral surface of the side walls'8 orv substantially immediately. adjacent theretoas they grav i."

Patented Nov. 17, 1959 seen in Figures 2 and4-of the drawing. The vanes are itally descend towards the discharge opening 9. If such discharge opening was completely open, notwithstanding the provision of the suction duct 16 many particles of even: lighter; density would}, fall downwardly through the:v openingtogether with theparticles offheavier'unit mass. 5 weights. In; order to prevent this condition, and efiect' a; thorough separation; between, theheavier and lighter density particles, the louver 21 is positioned across. the, separator adjacentthe discharge. opening 9 so-asg to permit only the heavier or more dense particles to gravitally 10 descend and be. discharged from the separator through the, louver; andpermit a vertical rising ofonly the lighter particles under influence of; the suction blower-17; and theduct 16. r

With particular reference to, Figures 2 through 4 ofthe. drawing, it. will be seen that; the louver 2l is positioned subjacent the suction duct throat and the discharge, opening 9 and is provided with an imperfor'ate centralbafile portion 22 havinga. shallow frusto-conical body 23. The axis of the louver as Well as-that ofthe frusto-conical bo y. is alignedwith theaxis of the outlet 9 and the suction duct 16. As will be seen, the imperforate central portion has a diameter of approximately one-third of the overall louver'diameter, the latter corresponding to the diametrical extent ofthe separating chamber at the louver location. It is interesting to note that in the aforementioned copending application, the imperforate central bafile occupies a much larger portion of the louver. It is believed that the reason for this distinction is that with an open section louver, a smaller annular space is adequate to fulfill the volume requirements. Indistinction to this, where a close section type of louveris uti-' lized, it is desirable to have the same extend for the greatest radial extent possible without interfering with the proper functioning of the louver. However, by having the imperforate central portion rather than permitting the louver vanes to extend to the louver axis, far more efiicient separation is eifected and there is little tendency for the heavier components to pass'under the influence of the suction duct. Also, while the exact reasons-are somewhat obscure by reason of the difiiculty in determining forces and operational patterns in a separator, the conical baffle as shown is more efficient than a Hat baflle plate but either of such arrangements are believed an improvement on a completely open cross sectional area'at the throat.

The central imperforate portion 22 has a circular peripheral surface and such surface is spaced from the inner walls 8 of the separator so as to provide an annular space 26 therebetween. Disposed within such space are aplurality of vanes 27 and 28, each of which extend radially from the baffle periphery to the walls 8 of the separator. The vanes'27 are each substantially identical and are extremely deep and are provided with a generally vertical portion 29 which flares with an intermediate arcuate portion' into a generally horizontal portion 31, the latter terminating in a common plane. The portion 31 defining thev horizontal extent of the vane does not quite approach the horizontal but is angularly, related thereto as'will be positioned relatively close to one another and each of V the vanes 27 have a slight degree of overlapping. [Itzwill be appreciated that as the bottom of the separator as well as the louver itself tapers downwardly, the outermost edges 30 of the vanes are disposed immediately adjacent the separator side walls and likewise taper inwardly and downwardly.

Itwill be readily visualized that the vanes 27 by virtue; ofthe long vertical portions 29 are. far deeper than louvervanes heretofore utilized, and as an important:feature of the invention, disposed betweenv each pairof vanes 27. are intermediate vanes 28. Thellatter are substantially identical and. are positionedin. substantial par allel. relationshipto thevanes 27: but. extendlfrom: the. upper, ends thereot for: only one=quarten of the vertical. 75

extent of vanes 27. Thus, every other blade 27 is what. might be termed a full vane and the alternate vanes 28 are of a substantially lesser depth or less than one-half the depth of vanes 28. Furthermore, it will be clear that the vertical extent of vanes 27 is substantially greater than the horizontal extent thereof, whereas in the case of vanes 28, the horizontal'extent is the greater. This relationship is clearly illustrated in Figure 4 of the drawing. Once again, the exact phenomena of separation cannot be fully explained but it is believed that. any chaff, or light weight material which passes, for example, in the space A, may descend downwardly into the space B subjacent the lower edge of a vane 28 and thence be caught in up draft or current of air created by suction duct 16 and raised upwardly through the space C, thus following the path of the small arrows in Figure 4. The more horizontal or upper portions of all of the vanes are related to' thedirection of tangential air flow in the sep'arator'likewis'e as illustrated. in Figure 4 so. that the. carrier. fluid and'material upon descending to the level of the louver, will first engage the portions 31 of the vanes, the lighter materials then circulating up along the frusto-conical baffle member and the heavier components will continue moving downwardly and pass in thespaces; A and C completely through the vanes for collection.

It is believedthat' from the foregoing description, the constructional details as well as mode of operation of the. instant apparatus will be'understood, and field tests have-clearly shownthe superiority of this type of louver construction for separating particles of very minute; density diiferentials. With all uniform vane construc tion the high ratio of. separation has been unobtainablei but by reason of the alternate deep and shallow over-r lappingvanes, in combination with the imperforate bathe: portion in the; central area of the. separator, optimum separation has been effected.

What isclaimed is:

1. Apparatus of the character described including a. separating chamber having a lower discharge opening, a louver having a central impe'rforate portion disposed adjacent said opening and'including a plurality of vanes: extending radially outwardly from said central portion, each of such vanes having a cross-sectional form with? the upper portion extending generally horizontally and a lower portion extending generally vertically, alternate. vanes having a vertical extent in excess of the horizontal..- extent thereof, and the other vanes having a horizontal; extentin excess of the vertical extent thereof.

2.. Apparatus as set forth in claim 1 in which SEtld'i alternate vanes have a vertical extent substantially atv least twice, the vertical extent of their adjacent alternate.

vanes.

3. A louver construction for use with a material sepa-fi rator of the dry cyclone type comprising an imperforate. central portion, a plurality of vanes extending radially outwardly from said imperforate member, the cross-sectional shape of each of said vanes including a generallyfiat horizontal upper portion and a generally vertical; lower portion and an intermediate arcuate portion, each. ofsaid horizontal portions overlying a portion of its; adjacent vane, said vertical portions on alternate vanesi being substantially equal to each. other and .of greater vertical depth, than the horizontal extent of thevanes, and'the vertical portions of the other vanes beingsubstantially equal to each other and of a lesser vertical extent than the vertical portions of said alternate vanes..

4. Apparatus as set forth in claim 3 in which each. of;

. said alternate vanes has approximately three times the verticalextent of an adjacent. vane.

5. In'separating apparatus having a. housing provided with. a. tangential inlet at the upper end thereof, a central discharge openingat thelower end thereof, and an.

- axially aligned. suction duct having a lower throat: open said housing intermediate said throat and opening, said louver having a substantially imperforate central portion axially aligned with said throat and opening and covering approximately one-third the diametrical extent of said housing at the louver location, a plurality of circumferentially spaced vanes mounted on said central portion and extending radially outwardly therefrom, alternate ones of said vanes having a cross-sectional form including a horizontal portion substantially less than the vertical depth thereof and being positioned relative to an adjacent vane so as to be disposed in overlapping relationship thereto, and the other ones of said vanes having a horizontal portion extending in excess of the vertical depth thereof.

6. Apparatus as set forth in claim 5 in which said central portion is of flat inverted frusto-conical configuration.

7. A louver construction for use with a material separator of the dry cyclone type comprising a plurality of radially extending vanes, each of said vanes having a cross-sectional shape comprising a substantially horizontal upper portion and a substantially vertical lower portion, with the ends of the horizontal portions of the respective vanes vertically overlying a portion of its adjacent vane, and each alternate vane having a vertical depth at least twice as great as the vertical depth of its 10 adjacent vane.

References Cited in the file of this patent UNITED STATES PATENTS 1 2,638,181 Gordon May 12, 1953 2,638,218 Simpson et a1 May 12, 1953 2,638,219 Gordon et a1. May 12, 1953

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