CA1326697C - Cyclone separator with filter assembly for pneumatic conveyor - Google Patents

Abstract

CYCLONE SEPARATOR WITH FILTER ASSEMBLY FOR PNEUMATIC CONVEYOR
Abstract A cyclone separator (20) for a pneumatic grain conveyor (10) includes a filter assembly (60) mounted in the upper end thereof. The filter assembly (60) includes a cylindrical casing (62) extending into the separator (20) with a screen (70) therein and an adjustable accelerator plate (84) which cleans an adjacent portion of the screen and distributes the collected dust and foreign particles on the remainder of the screen. A second filter assembly (90) is preferably connected between the air outlet of the separator (20) and air inlet of the blower (52) for further dust and foreign particle removal.

Description

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~ 3 2 ,., , CYCLONE 5E2ARATOR WITH FILTER ASSEMBLY FOR PNEUMATIC CONVEYOR
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Technical Field The present invention relates generally to pneumatic grain conveyors, and more particularl~ to an improved cyclone ~eparator for a pneumatic grain conveyor incorporating an '' adjustable sëlf-cleaning filter arrangementO
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Pne~natic conveyors axe wideLy used today for trans-ferring grain and other types of granular material, Fox example, '~
, ~ such devices can be used for transferring grain from a storage -, , silo to a delivery truck, a laborious and time-consuming task ,''~
which was otherwise accomplished by shoveling. Such pneumatic ~'' conveyors generally include a cyclone saparator having a tangen- ,, ~`1 tial material inlet and a bottom axi.al material outlet. The suc- ~' tion side of a blower,is connected t:o an axial air inlet in the top~of the separator. The high prëcisure side of the blower in connected to a rotary valve which i~ connected between the mater~ial outlet of~the separator and a line leading to ,the point of~d-ischarge. Such devices have been mounted for mobility and ', adap~ed~for use~with power~ take-off'attachments on tractors to facilitate portabillty~and use in unloading various silos on a ^-ar~, for example.~
Pneumatic grain conveyor~s o this general type have been available for years under the name H~NDLAIR from Christianson Systems, Inc.;of~ Blomkest, Minnesota, the assignee hereof. See *Trademark 7~

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U.S. Pat. Nos~ 4,~33,946 and Des. 271,105.
The pneumatic grain ~onveyors of the prior art have generally ~ncluded some ~ype o~ filter or screen arrangement - between the air outlet of the separator and the inlet of the blower. These screens, of course, must be ~leaned periodically, the frequency of which depends upon the particular material being handled. Some foreign particles, such as nbees wings n can clog a filter in minutes~ Such i6cxeens ~metImes have been located in a transparent.section of the ~ipe between the separator and blower 60 that any clogging could be monitored. In addition, baffles . have been located between the material and air outl~ts within the . ~eparator to blo~k pa~sage of foreigD particles outward and into ~i the blower. ~his has been quite ef~ectivç with respect to the .~, larger dust and foreign particles which could cause the most damage to the blower, but.has not been particularly effectiv~
~ith respect to the lighter dust and for~ign particles which also add to the wear on the blower and contribute to clogging of the filter. A more restricti~e filter would capture more such par-ticles, but also increase the pressure drop and require a laryer, .~ heavier and more expensive blower. Heretofore, there has not been available a cyclone i~eparator inc:orporating a filter with a bafle plate arrangement adapted not only to block passage of the ~I large dust and foreign particles ~nto the air outlet, but also .I which effect$ self-cle ning of the filter so that a substantial J portion o the relatively smaller particles can also be collected :.~ on a certai~ portion of this screen in order to delay clogging.
nd thus interruption of ope~ation to clear the screen.
A need has thus arisen for an improved cyclone separator `3 ~ incorporating a~ int~rnal screen and baffle arrangem~nt whicb can ~ be adjusted in accord~nce with ~he particular material being con- -:~ veyed and which reduces clogging.

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Su~ of Invention ~ he present invention comprises an improved ~yclone ~ epArator which overcomes the foregoing and other difficulties ~ssociated with the prior art. In accordance with the invention, thexe ~s provided a cyclone separator for a pneumatic grain con-veyor incorporating an improved inter~al filter and baffle arrangement. A ~enerally cylindrical subhousing is mounted in th~ top end of the separator. The subhousing extends downwardly into the ~i~parat~r to def ine an air inlet therein located in ~paced-apart relationship with the material outlet at the bottom of th~ separatorO A cylindrical filter or s~reen is mounted in the housing b~tween the internal air inlet thereof and an extier- -nal air outlet. Seal means i~ provided between the cylinder and the housing ~o ~hat the air ~lows into the fil~er and outward.
movable ac~elerator plate or baffle is mount~d for adjustable posit~oning within the cylindrical filter so that the air is accelerated and deflected against an adjacent portion of the creen, which thus stays clean for a longer period of time and r~duced clogging. I~ desired, a fixecl baffle plate can be mounted between the in` inlet ~nd material outlet.
I~ accordance with the preferred construction~ a second air filter a~sembly is connected between the in outlet of the cy~lone separator and the in inlet of the blower, for further remoyal of dust and foreign particles. The second filter asssembly also includes a circ~lar baffle mounted on an axial shaft, not for accelerating airflow in order to effect continuous self-cleaning of a surrounding filter element, but for dividing ~;
the chamber therein so that dust particle5 can be collected for.
periodic removal without being sucked into th~ air outlet.

-'~ ' ' '- ';,'' 1326~7 : Brie~ Description of_Drawin~s A better understanding of the invention can be had byreference to the following Detailed Description in conjuction with the accompanying Drawings, wherein:
. Fig. 1 is a perspective view of a pneumatic grain con-veyor incorporating the filter assembly of the invention;
Fig. 2 is an enlarged, p rtially cut-away side view of '1 the cyclone separator of the invention.
'i Fig. 3 is i~ partial view of a pneumatic grain conveyor ~ having the second filter assembly of the invention; and .~ . Fi~. 4 is an enlarqed, partially cut-away side view of the ~econd filter assembly ~onnected between the air outlet of the cyclone separator and the air inlet of the blower.
Fi~. 5 is a partial top view showing the diverter arrangement.
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Detailed Descri~ n Referring now to the ~rawings, and particularly r~erring to Fig. 1, there is shown a pneumatic ~rain conveyor 10 incorporating air cleaner of the present invention. The pneuma-tic grain conveyor 10 includes a frame 12 having a pair of spaced-apart wheels 14 thereon for mobility. A tongue 16 is pro-vided on the front o~ frame 12, and a hitch 18 is provided on the front of the tongue for selective connection to a tractor or other suit~ble tow vehicle. The tOAgUe 16 is preferably longitu-dinally off~et from the center line of frame 12 for improved clearan~e when loading trucks or trailers, as will be explained ~ore fully hereinafter.
A cyclone 3epar~tor 20 is mounted on frame 12. The separator 20 includes a housing having a generally cylindrical upper side wall and a generally conical truncated lo~er wall as shown~ A~ axial air outlet 21 is located in the top wall of the separa~or housing. A tangential grain or material inlet 22 is provided in the ~enerally cylindrical upper wall of the housing of separator 20, A pipe or hose 24, which can be either rigid, semi rigid, or flexible is connected to the material inlet 22 and extends to a nozzle 25 for picking up the material to be con- :
veyed. For example, the hose 24 would t~pically extend into a bin or silo for removing grain or the like therefrom.
A rotary air lo~k conveying valve 26 of the flow-through ~
type is:secured to the material outlet 28 in the conical trun- ~- -eated lower portion of the housing of separator 20. The valve 26 in:cludes~a material inlet coupled directly to the material outlet ^
28 of separator 20, a material outlet 30, and an air inlet 32.
The ~alve 26 is typically hydraulically driven. A suitable valve iS commer~ially available from SemcoO ~he material outlet 30 is ;~connected to a dischar~e pipe 34 which extends upwardly and is :.
supported by an upright 36 on the rear corner of frame 12. A

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discharge cyclone 38 is provided on the end of pipe 34 for breaking the air lock and assuring that the grain or other material falls gently into an underlying trailer or truck (not ~hown).
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The discharge pipe 34 is preferably of split construc-tion to reduce clearance during transport of the pneumatic grain " conveyor 10 between sites. In particular, the discharge pip~ 34 ~ ~ncludes a pivotal upper portion and a fixed lower portion inter- --, connected by a coupling 40 like that shown in U.S. Pat. No.
'A 4,433~946, the disclosure of which is hereby incorporated by reference. The upper portion of discharge pipe 34 folds ~etween i,~ raised and lowered positions responsive to a crank or hydraulic cylinder arrangement.
The air inlet 32 of rotary valve 26 is connected by pipe 50 to the outlet of a hlower 52, which is driven through a gear box 54 by a shaft 56 connected to the power takeoEf ~PTO) attach-~ ment of a tractor (not shown3. For example, the RCS 409 or 1 RCS 412 blower from Roots division of Dresser Industries, Inc.
~1 can be used for the blower 52, which typically operates at about ~' 700-1600 CFM and 5-8 psi. The inlet of blower 52 is connected by J pipe 58 to a filter assembly 60 mounted axially in the top end of separator 20.
The blower 52 is a positive clisplacement air pump which draws air from the separator 20 in order to lower the pressure therein, and thus effect suction~on the material inlet 22 such `,~ that the grain or ~ther material to be conveyed is drawn inwardly ~-thus creating a vortex within the separator. The resulting centrifugal force causes the grain to move outwardly within the separator 20 as it swirls downwardly by gravity through the ~aterial outlet 2B an~ into valve 26~ from which it is forced by the pressurized air from blower 52 through the discharge pipe 34.
The swirling action within separator 20 results in separation of .-:' .~
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-- 7 _ chaff, dust and o~her foreign material from the grain which is entrained in the air and carried through the filter as~embly 60 and pipe 58 to blower 52 for pressurizatio~. Although filter assembly 60 is used, it will be appreciated that air containing a fair amount of dust and foreign material enters the blower 52.
If desired, a noise suppressor or silencer 61 can be connected betw?~en valve 2?~ and blower 52~
Referring now to Fig. 2 in conjunction with Fig. 1, the constru~tional details of the filter assembly ?oO can be seen Assembly 60 in?cludes a case or ?~ubhousing 62 secured to the air inlet in tbe top end wall of separator ?20. For purposes o?f clarity, the valve 26 ~ecured to the material outlet 28 at the bo tom end of the separator ~0 has been omitted. As shown, the housing 62 extends downwardly into the separator 20 tPrminating at an open inlet end 64 located in spaced apart relationship with the material outlet 280 A fixed baffle 66 is preferably positioned between the air inlet end 64 and the material out:Let 28~ The baffle 66 -~
comprises a circular plate which is r:igidly ~ecured to the bottom end of housing 62 by a plurality of support rods 68. The baffle 66 is preferably ~ircular and centerecl on the longitudinal axis of the separator 20, perpendicular thereto. ~he outer edge of baffle 66 is spaced i~wardly from the generally conical truncated lower wall ~or~ion of the separator to define an open annulus through which the grain or other separated material can swirl downwardly into the outlet 28- Baffle 66 is thus positioned in the center of the vortex created as air and grain is dxawn into the separator. Incoming air moves toward the center of the vor-tex and is drawn outw~rdly through housing 62, while baffle 66 ~unctions to preven large and ~edium particles of foreign matter ~r~m leaving the ~eparator 20 and entering the blower 52.

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A cylindrical filter or screen 70 is mounted in the upper end of housing 62. The screen 70 is secured between a removable cover 72 and an internal flange 74 within the housing 62. A threaded shaft 76 is also provided. The lower end of the threaded shaft 76 is secured to a pider 78, which is secured to the lower efnd of the housing 62 and the upper ends of the support rods 68. Shaft 76 extends upwardly through the screen 70 and a cPnter hole (not shown) in the cover 72, which is secured in place by a handle nut 80 screwed on the top end of the shaft. A
gasket 82 i~ also provided around the screen 70 within housing 62 and below the air outlet pipe 58 so that the flow of air through :
the f~creen is ~n the inside/out direction.
A movable accelerator plate or baffle 84 is provided inside the screen 70. The baffle 84, which is preferably ~ cir-cular plate, is mounted for movement along the shaft 76 and is secured in position as desired by jam nuts 85. As air passes upwardly from inlet end 64 of case 62 and into screen 70, it is a~celerated sutwardly around baffle 84 and through the annulus :~.
defined between the baffle and the screen, the adjacent portion of which is thus ~ept clean. This in turn results in an adjustable distribution of material collected on the inside of the screen 70 part of which is kept c:Lean by the self-cleaning action of the baffle 84. Positioning of the baffle 84 is `~
adjustable in accordance with the area of the screen desired to `--be kept clean. When the blower 52 is turned off, waste matter collected on the inside of the screen falls downwardly and collects cn the top of the fixed baffle 66 for clean out via :-access door 86 in the separator 20.
Although the baffle 84 has been illustrated as being of .-:
pla e-like cixcular configuration, it will be understood that it oould also be of cylindrical configuration, which in turn would result i-n a relatively lar~er area of screen 70 being impinged -f ~ . .
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: and kept ~lean. Further~ more ~han one baffle 84, of either cir-cular or cylindrical configuration, could be used, if desired, .~ with or without the fixed lower baffle 66.
Referring now ~o Fi~s. 3-5 t there is shown a second x filter assembly 90 which can be used with the pneumatic grain . conveyor 10 herein. ~he second filter assembly 90 can be used alone or in conjunction with the first filter assembly 60 and ~ the cyclone separator 20, although in the preerred embodiment ',~',~! both filter assemblies are desirable for maximum performance. As . described above, the first filter assembly 60 is primarily ~ adapted to remove large and medium particles of clust and foreign i~ . particles from air leaving the separator 20 and entering the ; blower 52. The second filter assembly 90, which is connected between ~he separator 20 and blower 52, is adapted for further ,' removal of medium and small particles of foreign ~atter in order to achieve ~ve~ better performance. However, the second filter assembly 90 does not in~orporate any filter elements therein and is adapted for convenient removal of dust and foreign matter collected therein in order to further minimize downtime from .1 interruptions during operation of the pneumatic conveyor 10 for ~, cleaniny, etc.
The second filter assembly 90 includes a generally j cylindrical c~5e or subhousing 92. Opposin~ pairs of lugs 93 are pxovided on ~he case ~2 for m~unting on a pair of uprights 94, which are secured at their l~wer ends to the frame 12 of the pneumatic conveyor 10O
. A tangential air inlet 96 and an axial aix outlet 98 are : provided at the upper end of case 92- A hinged door 100 is pro--~' vided at the lower end of the case 94. ~he door 100 is mounted on a hinge lnot ~hown) for swinging movement between an up and ~losed position and a down and open pOSition. The door 100 includes a handle 104- Latch~s 106 are provided about the lower . ~ - . .

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. - 10 end of the case 92 for selectively securing the door in the nor-mally closed position. A sealing gasket ~not shown~ is pre-ferably provided between the door lOD and the material outlet 106 defined by the lower end of case 92.
;, A baffle plate 108 is positioned within the case 92 between the air outlet g8 and the matérial ou~let 106. As is -~
best seen in Fig. 4, the baffle plate 108 comprises a circular i plate with a central hole therein mounted along a threaded shaft lln extendin~ along the axis of case 92. The baffle plate 108 is secured in place by shaf~ 110 by jam nots 111. The upper end of shaft 110 is secured to a spider 112~ which in turn is secured . within a cylindrical collar or extension 114. The extension 114 is secured at its upper end to the inside top end of case 92 a~out the air outlet 98. ~he extension 114 can thus be con-sideLed an extension of the air outlet 98 extending into the case 92. It will be noted that the open lower end of extension 114 extends downwardly within the case 92 to a level below that of the tangential air inlet 96 so that the i~ir and any dust or ~:
. foreign particles therein which enter the filter assembly 90 must ~.
swirl about the inside surface of the case 92 before turning and -~
entering the extension 114 for e~it througll the air outlet 98.
Rather than functioning as all accelerator plate as in . -the first filter assembly 60, the plate 108 of the second filter ~ ~ss~mbly 90 ~erves as an annular divider between the upper and 3 :lower portions of the chamber within case 92. For example, the outside diameter of plate 108, can be about 16-1/2 to 17 inches and the inside diameter of case 92 can be about 18 inches. As the air entering inlet 96 swirls within the upper end of the :-chamber, the dust and foreigin particles therein are driven out-wardly asainst the wall by centrifugal action and pass through : the an~ulus defi.ned about plate 108 for collection in the lower ^:
,~ end of the chamber. As the aix then turns for exit from the :~

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axial air outlet 98, plate 108 functions to prevent any dust or ~oreign particles collected in the lower end of case 92 from being ~ucked out therewith. Dust and dirt collected within ~ase 92 can later be removed via door 100. An access door 118 ~,j with a window ~not shown) therein is preferably provided in the side of case g2 for checking the amount of dust and foreign material collected therein.
-$ If desired, the second filter assembly 90 can be pro-vided with a bypass arrangement comprising a bonnet 120 defining one inlet snd two outlets. The inlet of bonnet 122 is connected to the ou let 58 of separator 20. One outlet of bonnet 122 is connected to the inlet g6 o case 92, while the other outlet is connected through a butterfly valve 122 to a tee 124 in pipe 58 Valv~ 124 is controlled by handle 126. The second filter ~ assembly 90 can thus be selectively connected or disconnected for `~ bypass as desired depending upon the type of grain being handled ~nd the need for additional fiLtration.
'3 From the foregoing, it will thus be apparent that the present invention comprlses an improved cyclone separator for a pneumatic grain conveyor having several advantages sver the prior art. One advantage involves the fact that the filter is located .~ within an extension of the separator, instead of in a restricted connecting line, resulting in less pressure drop or no greater pressure drop with a finer mesh screen. The adjustable baffle ,~ either with or withoyt the lower fixed baffle, keeps at least a portion of the screen clean which in turn results in a heavier build up of waste and foreign particles in the other portions of the screen than in turn fall away more readily under gravity when he blower is turned off. Other advantages will be evident to those skilled in the artO
~; Although particular embodiments of the invention have the foregoing Detailed Description, it will be understood that ., ~ . :
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. but is intended to embre e any alterneat'ves, equivalents, modiii~

cope of the invention as defined by the following Claims.
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Claims (3)

1. A pneumatic grain conveyor, comprising:
a frame;
a cyclone separator mounted on said frame, said separator including a closed housing with a generally cylindrical upper side wall with a tangential material inlet and an air outlet in a top end wall, and a generally conical truncated lower side wall with a material outlet at a bottom end thereof;
a first filter assembly mounted in said air outlet of said separator, said first filter assembly comprising:
a generally cylindrical subhousing extending axially into the top end wall of the housing of said cyclone separator, said subhousing having an external top end and an internal bottom end;
a generally cylindrical screen with top and bottom ends disposed within said subhousing;
a first transverse baffle plate mounted inside said screen between the ends thereof, said first baffle plate defining a predetermined open annulus with said screen;
means for adjustably positioning said first baffle plate longitudinally within said screen;
means defining a radial air outlet adjacent said screen in the top end of said subhousing;
a second transverse baffle plate mounted between the bottom end of said subhousing and the material outlet of said cyclone separator, a rotary valve including a material inlet connected to the material outlet of said cyclone separator, a material outlet, and an air inlet;
a blower including an air inlet connected to the air outlet in the top end wall of said cyclone separator, and an air outlet connected to the air inlet of said rotary valve means;
a second filter assembly connected between the air outlet of said separator and the air inlet of said blower; and means for driving said blower.

2. A pneumatic grain conveyor, comprising:
a frame;
a cyclone separator mounted on said frame, said separator including a closed housing with a top end wall with an air outlet therein, a generally cylindrical upper side wall with a tangential material inlet therein, and a generally conical truncated lower side wall with a material outlet at a bottom end thereof;
a filter assembly comprising:
a filter means for collecting particulate material from an air stream, said filter means further comprising a generally cylindrical filter element mounted in the air outlet of said cyclone separator whereby the particulates are collected on an inner surface of said element, and means for selectively cleaning the collected particulates from said filter element while said pneumatic conveyor is in operation wherein said cleaning means comprises means for directing all accelerated airflow against selected portions of said inner surface of said element;
means for removably mounting said filter assembly in the air outlet of said cyclone separator;
a rotary valve including a material inlet connected to the material outlet of said cyclone separator, a material outlet, and an air inlet a blower including an air anlet connected to the air outlet in said cyclone separator, and an air outlet connected to the air inlet of said rotary valve; and means for driving said blower.

3. A pneumatic grain conveyor, comprising:
a frame;
a cyclone separator mounted on said frame, said separator including a closed housing with a top end wall with an air outlet therein, a generally cylindrical upper side wall with a tangential material inlet therein, and a generally conical truncated lower side wall with a material outlet at a bottom end thereof;
a filter assembly comprising:
a filter means comprising a generally cylindrical filter element mounted in the air outlet of said cyclone separator for collecting particulate material from an air stream on an inner surface of said element, a baffle plate adjustably mounted along a central longitudinal axis of said filter element within said filter element and defining an annular opening between said plate and said inner surface of said element whereby an accelerated air flow is directed against selected portions of said inner surface to selectively clean the collected particulates while the pneumatic conveyor is in operation;
means for removably mounting said filter assembly in the air outlet of said cyclone separator;
a rotary valve including a material inlet connected to the material outlet of said cyclone separator, a material outlet, and an air inlet;
a blower including an air inlet connected to the air outlet in said cyclone separator, and an air outlet connected to the air inlet of said rotary valve; and means for driving said blower.