US3002625A - Screening and comminuting device - Google Patents

Description

1961 w. H. LANNERT 3, 02,

SCREENING AND COMMINUTING DEVICE Filed May 19, 1954 3 Sheets-Sheet 1 Oct. 3, 1961 W. H. LANNERT SCREENING AND COMMINUTING DEVICE 3 Sheets-Sheet 2 l7 Wa 74% /i J zyg ma'da F QQ- Q Filed May 19, 1954 Oct. 3, 1961 w. H. LANNERT 3,002,625

SCREENING AND COMMINUTING DEVICE Filed May 19, 1954 3 Sheets-Sheet 3 LZZJWLZOZ YJiMCl/DL fl fizz/01 25 3,002,625 Patented Oct. 3, 1961 United States Patent ()fiice 3 062 625 EfsCREENlNG AND itosnausurmo DEVICE William ll. Lannert, Sirokie, 111., assignor, by mesne assignments, to FM'C Corporation, a corporation of Delaware Filed May 19, 1954, Ser.,No. 430,935 7 Claims. (Cl. 210-173) This invention relates to a transfer and comminuting device, and more particularly to means for transferring solids intercepted by a screen in a flowing stream of sewage to a comminuting device for comminution.

in accordance with the present invention an inclined screen extending across the influent channel intercepts all solids too large to pass therethrough. A cutting cylinder is rotatably mounted above the screen and in proximity thereto and in the normal sewage flow, adjacent the upper end of the screen. The screen is provided with longitudinally aligned, spaced screen bars, and the cylinder is provided with a plurality of series of laterally projecting teeth that are aligned transversely with the spaces between screen bars and are adapted tocarry solids from the screen and transfer them to the vicinity of a comb. The teeth cooperate with the comb to comminute the solids that are interengaged by the teeth. and comb. The position of the cylinder is fixed relative to the screen and therefore the teeth of-the cylinder can reach only the solids that have been intercepted by the screen in immediate proximity to the cylinder.

The present invention contemplates theprovision of means in combination with the screen and cylinderto periodically sweep or rake the screen and transfer the intercepted solids from the remote areas of the screen to the area of the screen within the rangeof the cylinder, so that the cylinder may reach thesolidsv and carry them to the cutting comb for comminution.

In order to bring the -cutting cylinder and the solids together it has been proposed to have the cutting cylinder reciprocate in a longitudinal or horizontal direction adjacent the screen surface. so that the entire surface area of the screen is periodically swept by the cutting cylinder. This type of structure has proved to be satisfactory in, operation, but is relatively costly to make, operate and maintain, and is generally not feasible for small operations.

Another method is to provide a hopper-beyond and below the upper end of'thescreemand to move fingers longitudinallyof the screentopush. the solids into the hopper. The cutting cylinder forms onewall of the hopper and is adapted to-picktheisolids from the hopper and transfer them to the, comminuting. zone.

It has also been proposed to provide the cutting cylinder with laterally projecting tines as disclosed and claimed in the copending application of Carl H. Nordell filed December 17, 1951, under Serial No. 261,973, which issued as Patent No. 2,750,044 on June. 12, 1956. In this structure tinesproject from the. cutting cylinder and rotate therewith. The tines are extended their maximum distance as they pass upwardly through the screen and are gradually retracted as they approach the combpositioned adjacent the uppermost surfaceof the cylinder. As the tinespass through the screen they liftsolids intercepted by the screen, and thesesolids move downwardly towards the cutting cylinder by gravityas the times are rotated upwardly. Thenecessity of retracting the tines as they pass the comb-imposesv alimitation onvthe maximum length of the tines and, as-a consequence, the tines cannot extend far enough to remove solids from the entire surface of. the screen.

The present invention contemplates the provision of asimple, inexpensive. rake that may be used with. a cylinder of either type thatis, with or. without tines. The

rake iscapable of engaging solids intercepted by the screenoutside the range covered by the teeth of the cutting cylinder, and moving the solids upwardly along the upper surface of the screen into the area which is reached by the teeth. The teeth pick up the solids intercepted by the screen within the area reached by the teeth, and the solids moved into this area by the rake. The teeth of the cutting cylinder carry the solids to the area adjacent the comb and cooperate with notches in the comb to comminute the solids. The device of the present in vention is particularly suitable for use in operations such as in small cities and towns where the amounts of sewage to be treated are relatively small.

The structure by which the above mentioned and other advantagesof the invention are attained will be described in the following specification, taken in conjunctioncwith the accompanying drawings showing a preferred illustrative embodiment of the invention, in which:

FIG. 1 is a fragmentary perspective view of a channel through. which sewage flows, an inclined screen extending across the channel with its screen bars spaced transversely, a rake having posts extending between the screen bars, and a comminuting device mounted adjacent the upper end of the screen, all in accordance with the present invention;

FIG. 2 is a side view, partly in elevation andpartlyin section, showing the rake and. the means for movingit along the screen to bring the solids intercepted by the screen to the area reached by the teeth projecting laterally from the cutting cylinder;

FIG. 3 is a fragmentary perspective view of the mice;

7 FIG. 4 is a fragmentary side elevation of the rake, showingthe lowermost position .of the rake in dotted lines;

FIG. 5 is a cross sectional view, taken along the line 5-5 of FIG. 4.; and

FIG. 6 is a cross sectional view, taken along theline 6-6 of FIG. 4.

In the drawings, reference numeral 2 indicates an influent channel through which flows unscreened sewage carrying solids, and 3 indicates the efiluent channel through which the screened sewage flows along with the solids that are comminuted adjacent the upper end of the screen on which they accumulate. Channels 2 and 3 are parts-of a single structure, preferably made of concrete.

A screen 4 is supported in inclined position in channel 2 by means of a. pair of standards 5 extending upwardly from thebottom of the channel. Any form of screen may be used. The illustrative embodimentof thescreen shown in the drawings comprises a plurality of fiat metal ribbons disposed on the edges and held under tension in transversely spaced relationship. Suitable supports extending laterally from the side walls of the channel can be used instead of standards 5, if desired. The lower end of the screen can be secured to the bottom of channel 2 in any suitable manner. The screenis illustratedas being inclined at approximately thirty degrees, but it will be understood that this angle may be varied, as desired.

Screen 4-comprises a framed the outer edges of which are flush against the walls of infiuent channel 2. Frame 6 is provided witha centrally disposed opening 7 across which a plurality of individual screen elements 8 extend. These screenelements. are disposed edgewise and longitudinally ofthe screen, and are transversely spaced across the space between the longitudinal edges of frame 6;. A transverse bracket 9, (FIG. 2) secured to the underside of the upper transverse wall of framed, supports a plurality of leaf springs 16} which hold the upper ends of screen elements 8 under tension. Thetensioning device is fully described and claimed in the copending. application of Carl H. Nordell filed March 26, 1954, under Serial No. 418,944, which issued as. Patent No. 2,727,627 on Decem ber 20, 1955. The edgewise disposition of individual screen elements in a screen is claimed in the copending application of Carl H. Nordell filed March 27, 195 2, under Serial No. 278,822 as a division of application Serial No. 261,973, filed December 17, 1951, now Patent No. 2,750,044.

' A cutting cylinder 11, disposed horizontally relative to the screen, is rotatably mounted in bearings 12 supported on brackets 13 secured to the upper surface of frame 6. The cutting cylinder is provided at one end with a housing 14 which contains gears (not shown) operatively connected to a motor 15 for rotating the cylinder. Cylinder 11 is provided with a plurality of series of laterally extending teeth 16. The teeth are spaced longitudinally of the cylinder to coincide with the spacing between individual screen elements so that teeth 16 enter the spaces between adjacent screen elements 8 as the cylinder rotates. A stationary comb 18, supported by a bracket 19 secured to housing 14, extends parallel to the longitudinal axis of cutting cylinder 11, and is positioned adjacent the peripheral surface of the cylinder along a line spaced radially from the lineof contact between said cylinder and screen elements 8. Comb 18 is provided with longitudinally spaced notches or recesses 20 aligned with teeth 16 which cooperate therewith to comminute solids carried by the teeth as they pass through the notches.

The solids that are intercepted by the screen within the area reached by teeth are engaged by teeth 16 and carried by said teeth along the portion of the periphery of cutting cylinder 11 from the surface of the screen to the comb. The solids remain against the comb until they are forced through notches 20. In being so forced the solids arecomminuted and pass through the screen and into efiluent channel 3 along with the flowing sewage stream that has passed through the screen. A transfer device or rake, adapted to be reciprocated longitudinally of the screen, is provided for the purpose of moving solids that are intercepted by the portion of the screen out of the range of teeth 16 upwardly along the screen into the range of the teeth. The transfer device comprises a plurality of short posts 21 rigidly secured to a bar 22. Bar 22 is illustrated as being square in cross section, but it will be understood that it may have any shape. Each post is positioned between adjacent screen elements 8 and is of substantially the same thickness as the distance between adjacent screen elements so that they wipe the screen elements clean as the posts are moved longitudinally of the screen.

The opposite longitudinal edges of screen frame 6 are each provided with a downwardly extending flange 23 fitting against the walls of channel 2. A pair of ribs 24 and 25 projecting laterally from each flange 23 are spaced vertically to form a guide for a block 26 and a roller 27. Ribs 24 and 25 are parallel to the screen for most of their length, but turn downwardly sharply adjacent the lower end of the screen, as indicated at 28 and 29, for a purpose hereinafter described. A link 30 pivotally secured adjacent one end to block 26, as indicated at 31, is rigidly secured at its other end to bar 22. A roller 27 is rotatably secured to each end of bar 22 by a stud 32 which extends through link 30 and into the end of the bar.

A pair of hydraulic cylinders 33, mounted in any suitable manner adjacent the opposite longitudinal edges of screen frame 6, each has a piston rod 34 extending there from which is connected to block 26 by a clevis 35. The piston rods are reciprocated in any conventional manner by any suitable hydraulic system or other means, and move both blocks 26 in synchronization so that both ends of bar 22 move uniformly between the lower, foremost position, indicated in FIG. 2, adjacent the lower, forward end of the screen, and the rearmost, upper position, adjacent cutting cylinder 11, as shown in dotted lines in FIG. 2.

Throughout the major portion of the travel of bar 22 ribs 24 and 25 maintain rollers 27 and block 26 aligned. In this positionof rollers 27, the posts 21 project above screen elements 8 and are inclined towards the cutting cylinder. Posts 21 engage, solids intercepted by the screen and carry them upwardly to the teeth 16 as they are moved upwardly along the screen by the piston rods. The angular disposition of posts 21, aided by the sewage flow, also causes the solids to slide off the posts and be deposited on the screen as the posts are moved downwardly along the screen. Rollers 27 follow the track or guide formed by inclined portions 28 and 29 of ribs 24 and 2 5 at the forward end of their path of travel. This sharp angle moves posts 21 below the top surface of screen elements 8, as shown in dotted'lines in FIG. 4. Immediately after the start of the upward movement of the bar 22, posts 21 are moved upwardly to project above screen elements 8 and start moving solids intercepted by the screen upwardly along the upper surface of the screen. This arrangement prevents any accumulation of solids at the lower portion of the screen.

Although I have described the transfer device specifically in conjunction with a screenin which the screen elements comprise a plurality of flexible longitudinally extending, flat metal strips disposed edgewise and held taut in transversely spaced parallel relationship, it will be understood that theinvention is not so limited. The transfer device may be used with any planar screen in which the screen elements are disposed in the direction of travel of posts 21 and extend'in transversely spaced parallel relation, regardless of the specific cross sectional configuration of the screen'elements and whether they are flere ible or rigid, provided only that the longitudinally extending' spaces between adjacent screen elements are continuous throughout the length of the screen. The method of operation of the transfer and comminuting' device isvery simple. The apparatus is disposed in a stream of flowing sewage with the screen upwardly inclined in the direction of the sewage flow. The liquid sewage flows through the screen and through the efiiuent channel for further-treatment. The solids that are too large to pass through the screen are intercepted by it and are held against'the front surface of the screen by the force of the liquid sewage flowing through the screen. The posts are inclined upwardly so that as they are moving downwardly towards the lower end of the screen the solidsare washedfrom the posts onto the screen by the incoming sewage.-

' When the posts reach the bottom limit of their downward movement, as controlled by piston rods 34, they are lowered below the top of the screen and are then raised so that they may engagethe solids that may be at the lower end of the screen. The posts are then moved upwardly along the surface of the screen and in this upward movement the posts, which fit slidably between adjacent screen elements and project thereabove, wipe the screen substantially clean and push the solids intercepted by the screen upwardly along the upper surface of the screen until they reach the area within the range of the teeth of the cutting cylinder. The dynamic force of the liquid flowing through the screen helps to carry the solids upwardly along the upper surface of the screen.

The teeth of the continuously rotating cutting cylinder pick up the solids from the screen and carry them to the comb of the comminuting device. The teeth pass through notches in the comb and cooperate therewith to com minute the solids. The comminuted solids, which are small enough to passthrough the notches in thecomb while the teeth are also passing through the same notches, then fall through the screen and flow through the efiiuent channel with the screened sewage. The process is continuous as long as the sewage continues to flow through the screen, the cylinder rotates, and the post carrying bar reciprocates.

I While I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details may be modified c -c ange w mo depa ng train. the spiri orsccp l r example, it ,isalso possib e to use to reciprocate the posts. Accordingly, I do not desire to berestrictcd to the exact constrnction described.

- I claim:

1. In combination, ascreen comprising a frame having downwardly extending flanges at its longitudinal edges and a, plurality of longitudinally extending, spaced parallel screen elements, a pair of vertically spaced ribs extending inwardly from each of said flanges, each of said ribs being inclined sharply downwardly adjacent the front end of said screen, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, a roller mounted at each end of said bar, each of said rollers being positioned between one of said pairs of ribs, a block slidably mounted between each pair of ribs, each of said blocks being connected to a piston rod operable to reciprocate said blocks simultaneously longitudinally of said screen, and a link connecting each block to the adjacent end of said bar, whereby said posts may be moved between said screen elements longitudinally of said screen.

2. In combination, a screen comprising a frame having downwardly extending flanges at its longitudinal edges and a plurality of longitudinally extending, spaced parallel screen elements, a pair of vertically spaced ribs ex tending inwardly from each of said flanges, a bar extending transversely of said screen, a plurality of posts rigidly secured to said bar and extending upwardly above the upper surface of said screen between adjacent screen elements, a roller mounted at each end of said bar, each of said rollers being positioned between one of said pairs of ribs, a block slidably mounted between each pair of ribs, each of said blocks being connected to a piston rod operable to reciprocate said blocks simultaneously longitudinally of said screen, and a link connecting each block to the adjacent end of said bar, whereby said posts may be moved between said screen elements longitudinally of said screen, said ribs being inclined sharply downwardly adjacent the forward end of said screen to cause said posts to move below the upper surface of said screen in their foremost position.

3. In combination, a screen adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, and a comminuting device positioned directly above said screen and adjacent one end of said screen, said comminuting device comprising a rotatable cylinder positioned in proximity to said screen and having a plurality of laterally projecting teeth and a comb spaced from said screen and in proximity to said cylinder, said screen comprising a frame having downwardly extending flanges at its longitudinal edges and a plurality of longitudinally extending, spaced parallel screen elements, a pair of vertically spaced ribs extending inwardly from each of said flanges, each of said ribs being inclined sharply downwardly adjacent the front end of said screen, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, a roller mounted at each end of said bar, each of said rollers being positioned between one of said pairs of ribs, a block slidably mounted between each pair of ribs, each of said blocks being connected to a piston rod operable to reciprocate said blocks simultaneously longitudinally of said screen, and a link connecting each block to the adjacent end of said bar, whereby said posts may be moved longitudinally between said screen elements of said screen to transfer solids intercepted by said screen along the upper surface of said screen to an area spaced from said cylinder a distance less than the distance to which said teeth project, said teeth being engageable with said solids transferred by said posts to lift said solids from said screen and guide them into engagement with said comb, said teeth cooperating with said comb to comminute said solids.

. 4. In, combination, a screen; adapted to, be interposed in a flowing stream of sewage for intercepting solidsin said sewage, a comminuting device positioned directly above said screen and adjacent one endof said screen, said comminuting device including a rotatable cylinder positioned in proximity to said screen and having a plurality of laterally projecting teeth movable between adjacent screen elements upon rotation of said cylinder, and a comb spaced from said screen and in proximity to said cylinder, said screen comprising a frame having a pair of vertically spaced ribs extending inwardly from each of its longitudinal edge gmrtions, each of said ribs being inclined sharply downwardly adjacent the front end of said screen, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, rotatable means for supporting each end of saidbar between one of said pairs of ribs, a block slidably mounted be.- tween each pair of ribs, each of said blocks being connected to a piston rod operable to reciprocate said blocks simultaneously longitudinally of said screen, and a link connecting each block to the adjacent end of said bar, whereby said posts may be moved longitudinally between said screen elements of said screen to transfer solids intercepted by said screen along the surface of said screen to an area spaced from said cylinder a distance less than the projecting length of said teeth, whereby said teeth lift said intercepted solids from said screen upon rotation of said cylinder and guide them into engagement with said comb, said teeth cooperating with said comb to comminute said solids.

5. In combination, a screen comprising a frame and a plurality of longitudinally extending parallel screen elements spaced uniformly transversely of said frame, said frame having a longitudinal edge portion provided with a pair of vertically spaced inwardly extending parallel ribs, each of said ribs being inclined sharply downwardly adjacent the front end of said screen, a raise comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being of a width substantially equal to the space between adjacent screen elements and spaced to fit within said spaces, a roller mounted on one end of said bar, said roller fitting between said ribs, a block fitting between said ribs and spaced longitudinally from said roller, a link connecting said block and said bar, and a piston rod connected to said block, said piston rod being operable to reciprocate said rake, thereby moving said posts longitudinally of said screen elements to transfer solids from the surface of the lower portion of said screen to a pre determined area of said screen.

6. In combination, a screen comprising a frame and a plurality of longitudinally extending parallel screen elements spaced uniformly transversely of said frame, said frame having a longitudinal edge portion provided with a pair of vertically spaced inwardly extending parallel ribs, each of said ribs being inclined sharply downwardly adjacent the front end of said screen, a rake comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being of a width substantially equal to the space between adjacent screen elements and spaced to fit within said spaces, a roller mounted on one end of said bar, said roller fitting between said ribs, a block fitting between said ribs and spaced longitudinally from said roller, a link connecting said block and said bar, and a piston rod connected to said block, said piston rod being operable to reciprocate said rake, thereby moving said posts longitudinally of said screen elements to transfer solids from the surface of the lower portion of said screen to a predetermined area of said screen, said posts being disposed angularly relative to the surface of said screen to facilitate transfer of solids to said predetermined area when said posts move in one direction, and to prevent sub- 7 stantial movement of solids when said posts move in the opposite direction.

7. In combination, a screen comprising a frame and a plurality of longitudinally extending parallel screen elements spaced uniformly transversely of said frame, said frame having a longitudinal edge portion provided with a pair of vertically spaced inwardly extending parallel ribs inclined sharply downwardly adjacent the front end of said screen, a rake comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being of a width substantially equal to the space between adjacent screen ele ments and spaced to fit within said spaces, a roller mounted on one end of said bar, said roller fitting between said ribs, a block fitting between said ribs and spaced longitudinally from said roller, a link connecting said block and said bar, and a piston rod connected to said block, said piston rod being operable to reciprocate said rake, thereby moving said posts longitudinally of said screen elements to transfer solids from the surface of the lower 8 portion of said scree'n'to a predetermined area-{ofscreen, said posts being disposed angularly relative to the surface of said screen to facilitate transfer of solids when said posts move in one direction and to prevent substantial movement of solids when said posts move in the opposite direction, said downward incline of said ribs causing downward movement of said rake'to move said posts below the top surface of the screen adjacent its lower end to facilitate removal of solids from the surface of said screen adjacent its lower end.

References Cited in the file of this patent UNITED STATES PATENTS 1,536,961 McMillan May 5}1925 1,823,823 Dundas et a1. Sept. 15, 1931' 2,614,695 Nordell Oct. 21, 19s

' 1 .FOREIGN PATENTSi l, 161,398 Germany Mar. 24,1903 590,146 Great Britain July 9, 1 47

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