US1961226A - Drier - Google Patents

Description

w' -Jllrl 5,1934. c. w. KEATLEY` Er-Al.

DRIERv iled Feb. 21. 1931 3 Sheets-.Sheet 2 0000 Zaoaa 0000 Jun 5, 1934. c. w. KEATLEY Erm` A 1,961,226

s sheets-sheet s Patented June 5, 1934 DRIER Charles W. Keatley, Castle Shannon, Guy V.

Woody, Mount Lebanon, and Collier H. Kear, Dormont, Pa., assignors to Koppers-Rhcolaveur Company, a corporation of Delaware Application February 21, 1931, Serial No. 517,446

20 Claims.

This invention relates to driers of the type disclosed in Patent No. 1,650,427 granted November 22, 1927 to Howard B. Carpenter, and the present invention has been developed in. order to simplify and improve the construction and operation of this type of drier.

One object of the invention is to decrease the air or wind resistance of the rotary screen, thereby reducing the amount of power required for driving the same.

Another object is to provide improved sealing joints between the rotary screen and stationary parts of the casing to prevent the escape of material between the casing and the screen.

Still another object is to provide means for retaining on the screen plates` a pad or bed of the material being dried.

A further object is to prevent excessive wear of the casing 4due to the impact of the material finally dischargedfrom the rotary screen.

A still further object to improve the construction and operation of the efiluentdischarge sluice-way.

/Other objects and features of novelty will be apparent as the following description proceeds, reference being had to the accompanying drawings, in which y Figure l is a view largely in section 'and partly in elevation of a drier embodying the improvements according to the present invention;

Fig. 2 is a detail section showing the preferred embodiment of the sealing joint between the feed hopper and the rotary screen;

3 is a'detail section showing the improved sealing arrangement for the bottom of the screen, and the wear plate for receiving the impact of the particles;

Fig. 4 is an enlarged detail section through the rotary screen adjacent -one of the reinforcing ribs, showing the improved arrangements for de creasing the wind resistance, and for mounting the screen plates and material retaining flange;

Fig. 5 is a top plan view of the structure shown in Fig. 4; Fig. 6 is a bottom plan view of the same;

Fig. 7 is a vertical section through the-v outer wall of the casing; e l

Fig. 8 is a. detail of the supporting member which carries the screen plates and the material retaining flange;

Fig. 9 is a section taken along the line IDI-' lX of Fig. 8:

Fig. 10 is a detail of the material retaining flange;

Fig. 11 is an enlarged detail section through being bolted to the lugs 30 and the adjacent portions of the hopper and rotary screen, showing a modified hopper sealing means, and the mounting of the upper screen plate; and Fig. 12 is a view similar to Fig. 3, showing the arrangement for retaining an impact cushioning bed of material on the casing wall adjacent the bottom of the rotary screen, as a modified expedient for preventing excessive wear.

Referring more particularly to the drawings, the drier disclosed in Fig. 1 comprises essentially a stationary casing 10 and a rotary screen 1l. In the form shown, the casing 10 comprises a top member 12 which forms a cover for the casing, and is provided with a hopper 13. Below the top 12, flanged and bolted thereto is an outer side wall 14.

Within the side wall 14 is mounted an inner wall 15 which is spaced therefrom by a flange 16. bolted to a corresponding ange on the outer Wall 14. Below the fiange 16, the inner wall is flanged andbolted to the upper flange of a supporting member for the entire structure. This member is preferably a channel 17, although an I-beam structure may be used in some installa.s tions. At this point is secured the top of a discharge chute 18 which delivers the dried material to a conveyor 19.

For supporting and rotating the' screen 11 a vertical shaft 2'0 is provided, 'the upper end of which is mounted in a conventional bearing not shown, and provided with suitable driving means. A lower bearing 22 `is being carried by a spider ,23, the outer ends .of which are bolted as at 24 to 'internal lugs of. the inner casing wall 15.

I'he rotary screen 11 comprises upper and low- 90 er spiders 27 and 28, which are keyed to the shaft 20. 'The arms of the upper spider 27 terminate in a conical rim 29, having peripheral lugs 30. 'I he lower spider 28 is keyed to the shaft -20 slightly above the bearing 22. 'I'he ends of the spider 95 arms carry a lower base ring 32, being preferably cast integral therewith.

'Ihe peripheries of the spiders 27 and 28 are connected by a plurality of rib members 34, ar-- ranged generally in the form of a pyramid, being disposed-in spaced relation. The ends of the rib members 34 terminate in pads 35, the upper pad lower pad being bolted to the rim 3 2.. V 1'05 The rib members 34 are provided with offsets 37 4 Itherein, which offsets give the rib members al .stepped conguration. In cross-section, the rib members 34 are preferably T-shaped, the flanges of the rotary screen, and the web thereof projecting radially outwardly therefrom.

Fitted to the inner side of the rib members 34,

labove and below the offsets 37, are a plurality of screen plates 39. While various kinds of foraminous material may be employed for this purpose, perforated chromium alloy steel plates have been found very satisfactory in operation.' The screen plates 39 are frusto=conical sections, and when fitted to the ribs 34 in the manner described above, these plates 39 form a series of stepped frusto-conical screens.

The entire screen surface and the load of material carried thereby, are supported by the rib members 34 which span the space between the upper and lower spiders of the rotor. 'I'he rotary screen develops a very high speed during the drying process, and the consequent centrifugal force results in a heavy load on the ribs 34 acting as beams. For this reason, the web of the T section thereof has heretofore been made very deep. This is undesirable, as the depth of this web projects transversely to the direction of rotation and results in an enormous wind resistance to the rotation of the screen.

In order to decrease the depth of this flange 36 and thereby decrease the wind resistance, without sacrificing the strength necessary to withstand the centrifugal force developed, there has been provided a plurality of reinforcing rings -40. The mounting of these members is shown in detail in Figs. 4 and 5 as being associated with the corresponding offsets 37 in the rib members.

Being continuous around the rotor, these rings reinforce the rib members to such an extent that the depth of the web 36 may be materially decreased, the load heretofore taken thereby being taken by tension in the ring members 40. The

web 36 is notched as at 42 to receive the ring 440l and this web is also bossed as at 43 to receive a retaining bolt 44 for the ring.

For supporting the screen plates 39, members 45 are carried by the ribs 34, extending between corresponding offsets 37 in the ribs 34. Details. 4 of a member 45 are shown in Figs. 8 and 9. This member is preferably a casting in the form of a Z-bar, having flanges 46 and 47 connected by a web 48. The Z-bar member is curved in such a manner that the flanges 46 and 47 and web 48 thereof are conical surfaces. The ends of the flanges 46 and 47 are notched away, leaving the web projecting at each end, as at 49.

The portions 49 are fitted under the offsets 37 and secured by screws 50 to the flanges ofthe T ribk 34, the notched portions of the flanges 46 and 47 serving to clear the flanges of the Trib. The inner upper flange 47 forms a base to which is secured, by means of bolts'51, the lower margin of the screen plate 39 above the offset 37.

'I'he lower outer flange 46 forms a base to which is`secured the upper margin of the screen plate 39 therebelow by means of bolts 52. Thus the member 45 serves as a rigid supporting base and attaching means for the adjacent screen plates 39.

The member 45 also serves as a support for a retaining flange 53 offsets 37. This flange serves to retain a pad qr bed of material thereabove on the screen plate. This pad of material has' several important functions.

There has been a tendency for the liquid to flow on down the inside of the conical screen, instead of passing therethroug The pad of ma-' terial above'the flange 53 absorbs the water and thus retains the same, to

associated with each of the facilitate vthe action of centrifugal force in causing the water to be forced through the perforations.

Furthermore, the pad of material retained by the flange 53 acts as a filter bed to retain the fines and thus improve the separation. This pad of material also acts to cushion one screen against impact thereagainst of material from a screen thereabove, and serves to protect the screen plate from consequent rapid wear.

The member 45 provides a very convenient means for attaching the flange 53. As shown in detail in Fig. 10, this fiange 53 is-notched as at 54 to receive bolts 55 whereby the fiange is adjustably secured to the web 48 of the Z-bar 45. Thus the flange 53 may be moved in or out as desired, in order to adjust the depth of the cushioning bed of material retained on the screen 39.

Intermediate the flanges 53, smaller annular angles 56 are secured to the screening material in any desired manner, as by bolting, riveting or welding, and they serve to retain smaller beds of material for the same purposes. These angles also reinforce the screenbetween the supports 45.

With driers of this type heretofore employed,

. there has been considerable leakage between the hopper 13 and the upper spider rim 29 of the screen. The centrifugal force developed has had a tendency to project the material received from the hopper 13 out through the space between the hopper and the rim 29.

To improve this condition, there has been developed the structure shown in detail in Figs. 2 and 11. The form shown in Fig. 2 is preferred, but the modification shown in Fig. 11 effectively prevents any leakage.

As shown in Fig. 11, a conical plate 57 is secured by screws 58 to the bottom of the hopper 13. The hopper 13 being conical, the plate 57 is normal thereto at all points, forming an annular groove, which conforms to the upper rim of the screen element.

The hopper part 13 fits over, and the plate 57 snugly underlies the upper edge of the rim 29 and extends therebelow a sufllcient distance to prevent escape of material fed by the hopper 13. Thus the clearance between the parts is so arranged that the direction of action of the centrifugal force is opposed to the direction of movement of the material necessary for the escape thereof. i

'I'he preferred form shown in Fig. 2 preserves all of the advantages mentioned above, and also facilitates assembly of the machine. In lieu of the plate 57, a ring member 59 is provided, which has a cylindrical face engaging a cylindrical face vertical adjustment of the sealing flange, the bolt holes being enlarged'or elongated for this purpose. 'I'hus a uniform'and accurate clearance may be maintained after the machine is -assembled.

As shown in detail in Fig.- 3, an improved ar- -rangement is provided for sealing the joint between the bottom of the rotary screen and the pendicular to the direction of action of the centrifugal force. The web 61 of the rim 32 not only 4of the hopper 13. This arrangement permits serves to improve the seal with the casing Wall 15, but also serves as an abutment to support the lower edge of the screen plates 39. The screen plates 39 are notched out to clear the ends of the spider arms 31 where theyvjoin the rim 32.

The wear due to impact of particles under the great amount of centrifugal force developed in this type of drier has been detrimental to portions of the casing. One expedient for protecting the casing is shown in Fig. 12. A flange 624 projects inwardly from the casing wall 16 a short distance below the flange 60 and forms an annular chamber therebetween. This chamber is intended to receive material thrown oil. the lower.

edge of the screen plate 39, and retain a sufficient amount thereof to form a cushioning bed, so that the impact of later particles will not result in serious wear upon the casing wall 15.

The preferred construction for contending with this condition is shown in Fig. 3. In lieu of the flange 62, wear plates 63 of harder metal are provided, which form a liner for the casing wall 15 below the flange 60.

The inner surfaces of the wear plates are smoothly rounded so as vto deflect the material downwardly toward the d'scharge chute 18. The plates 63 are secured to the wall 15 by bolts 64. The segmental construction thus afforded facilitates installation and replacement of the protective liner formed thereby.

The structure shown in Fig. 7 facilitates th removal of the eilluent material from the casing after it has been thrown off by the screen. The lower portion of the outer casing wall 14 is conical as shown at 65, and as the inner cas'ng wall l5 is vertical, this tapering of the outer wall 14 results in a restricted channel at the bottom of the chamber therebetween.

Furthermore, the conical portion 65' carries a plurality of inwardly projecting spiral flanges 66, each of which begins at a thin' edge 67 at the bottom of the wall 14 and extends upwardly along the portion 65 to a high point 68. From the point 68 the flange depends vertically as at 69 leaving a space 70 between the portion 69 `and the adjacent edge 67 of the next flange. There are fourflanges 66 equally spaced around the inner face of the outer casing wall 14.

In view of the tapered character of the conical portion 65, the spiral flange is Wider at the high portion 68 than at the lower edge 67. Thus the channel formed by the portion 65, spiral flange 66 and the outer surface of the inner Wall 16 is restricted in two directions. materially increases the velocity of travel of eiiluent material to the space '70 which forms a discharge aperture. Below each aperture 70 a discharge chamber 71 is provided for connection to a discharge pipe 72. i

The increase in velocity due to the tapering passage is important inasmuch as the effluent liquid generally contains a certain amount of sludge which would tend to clog the passage without this increased velocity provision. If extraordinary conditions demand further aid in the discharge of the effluent material, water pipes 73- are in the nature of improvements on a known` type of drier, nevertheless the improvements are of' major importance inasmuch as they determine the commercial success or failure of the This construction.

drier. Furthermore, the various improvements cooperate with each other in such manner as to greatly improve the Whole. Therefore, while the improvements have been described in considerable detail, the scope of the invention is not to be limited to the exact details disclosed, but instead embraces such embodiments of the dis- 4fall within the scope of the ap-Y closed ideas as pended claims.

We claim as our invention':

1. In a drier, a downwardly and outwardly ta-v pering rotary frusto-conical screen, and an annular flange projecting inwardly from said screen and adapted to retain on said screen a bed of the material being dried the inner end of sad flange being normal to said screen.

2. In a drier, a rotary screen comprising downwardly stepped surfaces of screening material, anda flange for retaining a bed of material on one of said screen surfaces to cushion the impact of the material discharged thereon from another screen surface, the inner end of said flange being normal to said screen.

3. In a drier, a rotary screen comprising rib members having offset portions formed therein, annular reinforcing rings connecting said offset portions, and screening material rigidly secured to and reinforced annularly by said reinforcing rings.

4. In a drier, a rotary screen comprising rib members having offset portions formed therein, annular reinforcing rings connecting said offsei portions, and frusto-conical screening material rigidly secured to and reinforced ann'ularly by said reinforcing rings` between rib members and between said offset portions.

5. In a drier, a rotary screen comprising an upper rim, a lower rim, rib members connecting said rims and having offsets formed therein, annular members connecting corresponding offsets of adjacent rib members, frusto-conical screen plates secured to adjacent annular members, a flange projecting inwardly normal to said'screen plate, and an adjustable mounting for said flange on one of said annular members to permlt adjustment of the inward projection thereof.

6. In a drier, a stationary casing part, a rotary frusto-conical screen part mounted to rotate therein, one of said parts having an annular groove, and the other part having an annular rim conforming to said groove, wherebythe clearance therebetween is transverse to the direction of centrifugal force due to rotation of said screen part, and means for adjusting one of said parts to conform to the other of said parts.

7. In a drier, a stationary frusto-conical hopper, a rotary frusto-conical screen and an annular member carried by said hopper and having a flange underlying the upper rim of said rotary screen, said annular member being adjustable from the exterior of said hopper and screen.

8. In a drier, a rotary screen having an annular rim and a casing having an inwardly projecting ange underlying said rim, said casing having a second inwardly projecting flange spaced therebelow and defining therebetween a chamber for retaining a shock absorbing cushioning bed of material being screened therein between the casing and the annular rim in the path of subsequent material discharged therefrom.

9. In a drier, a chamber having an annular wall, the lower portion of said wall being conical and provided with an inwardly directed spiral flange decreasing in widthv towards the bottom of the spiral as said conical wall decreases in bottom of the spiral to eiect an acceleration in 1 velocity of effluent llowing therethrough.

10. In a' drier, a rotary screen, a casing having inner and outer annular walls,'said inner wall having an inwardly directed flange projecting into an annular groove in the lower Vrim of said screen, and a ange therebelow forming there with a material retaining chamber, one of said walls having spiral anges each extending to the other wall and forming .therewith an annular series of efuent sluice-waysl having inclined bottoms, with discharge ports at their lower ends, and one of said walls being conical and thereby gradually narrowingv the sluice-ways so as to decrease their cross-sectioned area towards the discharge ports to increase the rate of flow of eiliuent along the flanges.

11. In a drier, a rotary screen, a casinghaving inner and outer walls, said inner wall having an inwardly directed ange in sealing engagement with the lower edge of said rotary screen, one of said walls having a spiral flange extending to the other wall and forming therewith an eilluent sluice-way having an inclined bottom, and means for directing a jet Aof fluid onto said spiral ange to wash down sludge thereon.

12. In a drier, a casing, a rotary frusto-conical screen in said casing comprising upper and lower rims, rib members connecting said rims and having offset portions therein, annular elements connecting said offset portions, frusto-conical screening material carried by said annular elements between said rib members and between said oiset portions, annular flanges adjustably secured to said annular elements and projecting inwardly therefrom normal to said screening material to retain a bed of material thereon,

annular reinforcing rings outsidei ofwsaid rib members and secured thereto adjacent said olfi sets, and means for preventing escape of the material being dried between said screen and the adjacent rims of saidcasing.

13. In a drier, a rotary frusto-conical screen comprising an upper circular rimfa larger circular lower rim, and rib members connecting said rims and converging toward said upper rim, `said rib members having -offset portions in a plane parallel to said rims, and a reinforcing ring secured to the upper outer side of said offset portions.

14. In a drier, a rotary frusto-conical screen comprising an upper circular rim, a larger circular lower rim, and rib members connecting said rims and converging toward said upper rim, said rib members having offset portions in a plane parallel to said rims, an annular member connected to the underside of the -oset portions of two adjacent rib members, an inwardly projecting'ange secured to said, annular member and having slots therein, and means passing through said slots for adjustably securing saidange to said annular' membe 15. In a drier, a rotary frusta-conical screen comprising an upper circular rim, a larger circular lower rim, and rib members connecting said rims and converging toward said upper rim, said rib members having oiset portions in a plane parallel to said rims, an annular member connecting the oisets of adjacent rib members, an upper screen plate secured to the inner side of said annular member, and a lower screen plate secured to-the outer` side of said annular member.

16. In a drier, a rotary frusto-conical screen comprising'an upper circular rim, a larger circular lower rim, and' rib members connecting said rims and converging-toward said upper rim, said rib members having oiset portions in a plane parallel to said rims, a ring secured to the upper side of said offset portions, and an annular member secured to the under side of said offset portions.

17. In a drier, a rotary frusto-conical screen comprising an upper circular rim, a larger circular Alower rim, and rib members connecting said rims and converging toward saidupper rim,

. screening material secured within said rib members, an annular angle having a flange secured to said screening material and another ange projecting inwardly normal to the surface of said screening material to retain a pad of material being screened thereon over which other material being screened may pass on down the screen and thereby provide for absorbing any liquid that tends to escape centrifuging and run down the screen. a

18. In a drier, a rotary screen comprising an upper circular rim, a lower larger circular rim, rib members connecting said rims and having oilset portions, a ringsecured to the upper side of said offset portions, anda Z-bar connecting the adj acentrib members.

'upper circular rim, a. lower larger circular rim, rib members connecting said rims and having oiset portions, a ring secured to theupper side of said oiset portions, and a Z-bar connecting the underside of corresponding offset portions of adjacent rib members and screening material secured to a ilange of said Z-bar.

20. In a drier, in combination, a rotary frustoconical screen comprising an upper circular rim, a larger circular lower rim, and rib members connecting said rims and converging toward said upper rim, a casing comprising a hopperin sealing engagement Awith said upper rim, -an inner wall in sealing engagement with said lower rim,

19. In a drier, a rotary screen comprising an and an outer wall connected to said hopper and said inner wall, one of said walls having a spiral flange tapering in width and downwardly inclined towards a lower outlet end and extending to the other wall and forming thereby a sluiceway of gradually diminishing cross-sectional area towards the outer end.

, CHARLES W. KEATLEY.

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