Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
  • B01D45/12—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
  • B01D45/14—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces generated by rotating vanes, discs, drums or brushes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D50/00—Combinations of methods or devices for separating particles from gases or vapours
  • B01D50/40—Combinations of devices covered by groups B01D45/00 and B01D47/00

Definitions

• the present invention relates to centrifugal sep ⁇ arators and in particular, to devices that remove particles or other constituents by radially impelling the particles or other constituents out of a contaminated stream of fluid.
• a known centrifugal scrubber employs a cylindrical housing having a tangential inlet port into which a contamin ⁇ ated stream is injected. Because of the manner of injection, the stream flows helically through the housing before exiting from an outlet port. These scrubbers typically spray into the stream a scrubbing liquor to facilitate removal of pollu ⁇ tants from the stream. Dynamic wet scrubbers are also known and these devices employ a fan-like device into which is in ⁇ jected a contaminated fluid stream together with a spray of scrubbing liquor.
• separators which employ nested- conical frustrums which are spun as a stream of contam- - inated air flows between them. These nested structures are perforated to allow particles, droplets, and other effluents adhering to their surface to pass outwardly and be captured in a surrounding housing.
• a disadvantage of the foregoing devices is a signif ⁇ icant pressure drop occurring across the unit. Also many of these devices fail to control the vortex to reduce energy-con- suming turbulence. In addition, known devices drive captured particles or other pollutants in the same direction as the in ⁇ coming stream of contaminated fluid, thereby increasing the likelihood of re-entrainment. Further, they do not remove all or substantially all the particles or other pollutants from the contaminated stream.
• a centrifugal separator apparatus for cleansing a stream of fluid.
• the separator includes a tapered fluid passage or conduit having an inlet and an out let.
• the passage is bounded by a tapered wall which is rot ably mounted to provide a converging rotatable fluid passag from the inlet to the outlet.
• a method for separating particles entrained in a fluid by means of a tapered, rotatable conduit or duct includes the step of directing the fluid into the co duit in the same direction as that of its taper. Another s is rotating the conduit to radially impel the entrained par icles against the inside of the conduit and then to remove particles by causing them to flow in a direction opposite t the direction of flow of the fluid, to a particle exit.
• an apparatus for cleansing a stream of fluid comprising a vortex means having an inside surface that converges in a downstream direction.
• This vortex means includes a means for radially impelling the fluid against i inside surface.
• the vortex means may have a plurality of i ternal baffles, and a portion of each baffle may be skewed with respect to the axis of rotation of the vortex.
• a relatively efficient separator is provided.
• This separato preferably employs a spinning frustro-conical drum having i ternal baffles that guide incoming fluid towards an outlet and assures- that all fluid is brought to rotational speed.
• This drum can be tapered from its inlet to its outlet so tha particles driven against its inside surface tend to reverse their direction of flow and migrate towards the wider end (inlet) of the drum.
• the spinning drum comprises nested fr tro-conical conduit sections with a plurality of interstitia baffles having curled leading edges. This feature simultan ⁇ eously draws in air, reduces turbulence, and develops a rad- ial centrifugal force field for particle separation.
• a scrubbing liquor is sprayed into an incoming stream of contaminated air to capture en ⁇ trained particles and/or gaseous constituents.
• the particu- lates of the mixture are then radially impelled and captured by the above-mentioned spinning drum.
• the captured scrubbing liquor emerges at the wider end of the drum and may be recycled to the sprayer.
• the spraying occurs up ⁇ stream of a plurality of stacked, spaced plates which precede the spinning drum. These plates provide first surfaces onto which heavy droplets of spray can settle. Thus, the plates provide an initial site for capture of particles and droplets that have seized or captured pollutants.
• An advantage of the plates is that they are passive, require low energy, and promote uniform flow to reduce turbulence.
• the drum is spun on a vertical axis, its narrow end up. Incoming air is then drawn upwardly while particles, liquid droplets and other contamin ⁇ ates are then impelled radially outwardly and then downwardl . Since this reversed flow is downward, the force of gravity assists the separation process.
• Figure 1 is a perspective view of a separator accord ⁇ ing to the present invention
• Figure 2 is a sectional view of an alternate construc ⁇ tion which may be employed in the separator of Fig. 1;
• Figure 3 is a left end view into the base of Fig. 2.
• FIG. 4 is a perspective view of an inlet arrange ment for the construction of Figs. 2 and 3;
• Figure 5 is a schematic view showing the mode of operation of the construction of Figs. 2 and 3;
• Figure 6 is a sectional view illustrating a varia ⁇ tion of the separator in Fig. 1.
• a vortex means is shown herei as a tapered passage or conduit comprising an outer frustro- conical wall 10 and aninner cylindrical wall 12.
• the inter- space between walls 10 and 12 defines an airway in which a plurality of internal baffles 14 are mounted, sixteen in thi embodiment.
• outer wall 10 and inner wal 12 are formed of sheet steel (preferably stainless steel) an are welded to baffles 14.
• baffles 14, which have a curled -leading (lower) edge, are operable as a means.to radially impel the fluid pa sing through the spaces between the walls against the inside surface of outer wall 10.
• Walls 10 and 12 are rotatably mou ed on shaft 16 which is journaled in housing 18.
• housing 18 is a rectangular sheet metal box having an upper rectangular section in which sleeve 10 is mounted. It will be appreciated, however, that for other embodiments the shap of housing 18 may be altered depending upon the elements mou ed therein, the shape of the conduit formed by walls 10, 12 and the required compactness, capacity, weight constraints, etc.
• baffles 14 may be sized to intercept the supporting shaft 16.
• the number of baffles may be varied depending upon the desired flow rate, fluid density, spin rate, etc.
• wall 10 and its other components may be assembled, rather than by welding, by other fastening means such as, rivets, bolts, etc.
• baffles 14 are shown as vertical planes having a curled lower end, in other embodiments these baffles may be planar and skewed at an angle with respect to the axis to the rotation of the conduit. Aerodynamic shapes may be used for baffles 14.
• a plurality of settling plates 24 are mounted in the lower upstream portion of housing 18. These plates comprise a large number of para ⁇ llel spaced plates (forty or more with a one inch spacing in the embodiment illustrated) which are downwardly inclined in a downstream direction. It is to be appreciated that in other embodiments the plates may be non-rectangular and/or non-planar. They may be omitted for some applications.
• Mounted upstream of settling plates 24 is a spraying means shown herein as a pair of spraying manifolds 26 and 28 each having a plurality of nozzles 30. Nozzles 30 produce a finely divided spray of liquid, such as water. This liquid is supplied by means of pipes 32 which are fed by a circulation means shown herein as sump pump 34. Pump 34 draws liquid by means of perforated pipe 36 from the sump 38 at the bottom of housing 18 into con ⁇ duit 40, the input line of pump 34.
• Housing 18 has a pair of inlet ports to which are connected a pair of inlet ducts 40 and 42.
• An outlet port 44 in housing 18 is connected to output duct 46 connected to the inlet of blower 48 which operates to pump the fluid through the separator apparatus.
• Blower 48 has an exhaust duct 50 which returns cleansed air or fluid to the environ- ment.
• a filter 35 may be provided to clean the fluid being returned from sump 38 to spray nozzles 30.
• a clean water (or other liquid) spray may also be provided, downstream, of the settling plates 24, as shown at 25.
• Water or liquid for spray 25 is provided from a separate source through pipe 27.
• FIGs. 2 and 3 an alternate frustro- conical conduit is illustrated which may be substituted for that described in Fig. 1.
• the conduit comprises a nested tr of spaced walls 60, 62 and 64, each having a frustro-conical shape. Walls 60, 62 and 64 are bolted together by a plurali of bolts such as bolt 66.
• Bolt 66 is surrounded by upper bu ing 68 and lower bushing 70, which bushings act as spacers f walls 60, 62 and 64.
• baffle 72 comprise 32 planar elements, sixteen on each side of wall 62 Baffles 72 are skewed with respect to the axis of rotation o walls 60, 62 and 64 and spiral conterclockwise (as viewed in Fig. 3).
• Walls 60, 62 and 64 are mounted on a central barre 74, an annular spacer 76 being welded between barrel 74 and the larger end of wall 64.
• Barrel 74 is mounted on annular supports 78, 80 and 82.
• Supports 78 and 82 are mounted on hubs 84 and 86, respectively.
• Hubs 84 and 86 are mounted on rotatable shaft 88.
• Support 80 has a concentric apperture 90 through which shaft 88 passes.
• Figure 4 shows how the incoming contaminated fluid may be introduced into the spinning conduit of Figures 2 and 3.
• cleansed fluid passing out of the converging conduit defined by the taperin outer wall 10 is discharged into a diffuser section 11 which decreases the velocity and increases the pressure of the flu passing therethrough, thus increasing the overall efficiency of the separator apparatus.
• a fluid such as contaminated air contai ing particles, droplets, gaseous pollutants and other contam inants is drawn in through inlet ducts 40 and 42 into housin 18.
• the incoming air is then sprayed by nozzles or other methods of drop generation (such as a spinning disc impinger with a scrubbing liquor (such as water) supplied by manifold JR
• the liquid sprayed may be one which will react with the gaseous contaminants contained in the incoming con- taminated stream so that the gaseous contaminants are trans ⁇ ferred to the liquid.
• the spray from nozzles effectively produce an extremely large liquid surface area by finely dividing the liquid. Accordingly, the incoming contaminated fluid, usually air, contacts a relatively large liquid sur- face area so that the absorption of gaseous contaminants and adhesion of particulate contaminants occurs quickly and effic ⁇ iently.
• the sprayed mixture passes through the stacked set ⁇ tling plates 24 which are canted slightly downward.
• the larger liquid droplets and particles (for example, above 40 microns in size) settle and fall upon the surfaces of settling plates 24, thereafter flowing into the bottom reservoir or sump 38 of housing 18.
• the bottom of the res ⁇ ervoir is bled by drains 36 to pump 34 which recirculates the collected liquid through spray nozzles 30.
• the liquid may be cleaned by filter 35 before being re-sprayed.
• Inlets and outlets 33, 31 may be provided to add or remove water or other scrubbing liquid to or from the sys ⁇ tem.
• the unremoved portion of contaminants leaving set ⁇ tling plates 24 is drawn through the centrifugal separator 10, 12 and 14, which is being spun at a relatively high angular velocity.
• the resultant centrifugal force on the particles and liquid droplets (mist) in the fluid stream causes rapid outward separation of denser constituents to the inner sur ⁇ face of wall 10. Accordingly, particles and finely divided liquid droplets collect on the inner surface of wall 10, as shown in Figure 5.
• baffles 14 have a curled lower edge they act as airfoils to smoothly draw fluids inwardly and immediately impart to them an angu ⁇ lar as well as an axial velocity. This feature reduces the pressure drop across sleeve 10 and thus the work required to circulate the air throughout housing 18. Moreover, the air ⁇ foil design of baffles 14 reduce the turbulence at the upper or output end of the conduit formed by walls 10 and 12. Thi further reduces the work required since less engery is waste on producing non-productive turbulence.
• baffles 14 cause collision between those elements and droplets giving rise to greatly increased liquid surface area and it captures extremely fine particles of low micron sizes.
• Baffles cause pressure increase, which causes air to flow backwards through the seal area (Fig. 5) thereby keeping liquid from bypassing the separator.
• the fluid of airstream leaving conduit 10, 12 is a demisted, cleansed airstream.
• This airstream is drawn through outlet port 44 into duct 46 by blower 48.
• Blower 48 exhausts the cleansed air through duct 50.
• T particular liquid being sprayed may be chosen with regard to the particular contaminants in the fluid stream to be cleans
• the sprayed liquid may react with H_S.
• the contaminant mist may have sufficient particle affinity that the mist itself coalesces and is removed by the centrif ⁇ ugal separator. It is anticipated that for some embodiments the fore ⁇ going apparatus may be used to cleanse contaminants from a liq ⁇ uid. In this instance, the liquid input is through nozzles 30.
• a stripping gas is supplied through inlet ports 40 and 42 to remove contaminants from the sprayed liquid.
• the cleansed 0 liquid is then separated by separator 10, 12 and drawn off by pump 34.
• the cleansed liquid may not be recirculated but may be returned to a storage tank. Alternatively, the liquid pur ⁇ ity may be boosted by continually recirculating it.
• the strip ⁇ ping gas, laden with the contaminant may then be drawn out by 5 duct 50 and supplied to another separator constructed in the same manner as the apparatus in- Fig. 1.
• the latter separator may employ a liquid to remove the contaminants from the strip ⁇ ping gas as previously described.
• liquid 38 0 in sump 38 may be decontaminated by another separator con ⁇ structed similarly to that of Fig. 1.
• the contaminated liquid is sprayed, mixed with a ⁇ stripping gas, and routed to a spinning convergent conduit to separate the cleansed liquid and deliver it to a reservoir.
• Many chemical processes require an effective mass transfer of constituents between a gaseous and a liquid medi ⁇ um.
• the LeChatelier Principle may be utilized by the separator of this invention to shift a reaction equilibrium, thereby, withdrawing a contaminant.
• 0 a reaction of gas mixtures such as CO + H 2 0 CO Task + H_ may be assisted with the separator of the present invention.
• the separator can remove the liquid constituents 5 from the gaseous phase.
• the convergent spinning conduit may be rotated at different angular valocities, to produce centrifugal force within the range from 100 to lOOOGs, to provide best efficiency under various operating conditions.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Separating Particles In Gases By Inertia (AREA)
• Centrifugal Separators (AREA)

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• 1980
  • 1980-06-04 US US06/156,638 patent/US4375975A/en not_active Expired - Lifetime
• 1981
  • 1981-06-02 NL NL8120239A patent/NL8120239A/nl unknown
  • 1981-06-02 AU AU73749/81A patent/AU7374981A/en not_active Abandoned
  • 1981-06-02 GB GB8202236A patent/GB2089247B/en not_active Expired
  • 1981-06-02 WO PCT/US1981/000732 patent/WO1981003436A1/en not_active Ceased
  • 1981-06-02 DE DE813152066A patent/DE3152066A1/de not_active Withdrawn
  • 1981-06-03 CA CA000378926A patent/CA1182760A/en not_active Expired
  • 1981-06-03 FR FR8111005A patent/FR2483801B1/fr not_active Expired
  • 1981-06-04 IT IT22144/81A patent/IT1139340B/it active
• 1983
  • 1983-02-18 US US06/468,039 patent/US4468234A/en not_active Expired - Lifetime

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