US2696308A - Screening apparatus - Google Patents

Description

D 1954 w. $.MARTIN 2,696,308

SCREENING APPARATUS Filed July 5, 1951 |N\ IE NTOR WARREN S .".MARTIN .4 ATTORNEY United States Patent SCREENING APPARATUS Warren S. Martin, Massapequa, N. Y.

Application July 5, 1951, Serial No. 235,129

13 Claims. (Cl. 210176) The present invention relates to improvements in bar screens and cleaning means therefor for eflecting continuous interception and removal of solids and suspended matter or detritus from flowing streams of liquids, sewage for example, and more particularly to fine screens.

Screening apparatus of the same general character heretofore in use comprise screens having a plurality of slot-like openings for passage of liquid therethrough. In some instances solids or suspended matter carried by the liquid pass into the slots of the screen. The sweeping action of the prior cleaning device would then engage the screenings thus caught and move it'along said slot-like opening or openings to discharge it from the screen. If in this movement bodies in the screening engage a structural cross member of a screen it will be sheared into pieces which may pass through the screen. However, that portion of the screen may become cloggedand the screening action may become ineffective.

An important object of this invention is to provide a novel and advantageous bar screen which if distorted will be restored to its original form.

Another object of the invention is to provide a bar screen comprising wires arranged side by side fixed only by their lower ends at the bottom of a'channel.

Yet another object of the invention is to provide a bar screen and cleaning means therefor wherein .the

. provide intermediate teeth projecting between said wires.

screen comprises a sheet of wires fixed to the bottom of a channel, cleaning means for said sheet of Wires comprising cleaning rakes or combs moving from bottom to top of said screen and having teeth to enter between said wires and depressions between said teeth to receive said wires whereby said teeth enter the spaces between said wires and assist in opposing sidewise displacement of said wires and in restoring displaced wires to their normal positions.

Still another object of the invention is to provide in connection with a bar screen of parallel wires secured together at their lower ends, cleaning means comprising traveling cleaning combs or scrapers mounted to support said wires against pressure from the opposite side of the screen and traveling members at the opposite face of the screen to hold the wires against the pressureof said combs or scrapers.

According to one embodiment of the invention, the

wires are round and their lower ends are secured at the bottom of the channel in a line across the same. The

sheet made of these wires slants rearwardly against the flow of liquid and is engaged at its influent side by cleaner flights carried at their ends by sprocket chains passing around suitable sprocket wheels, two coaxial ones at the bottom of the channel and two coaxial ones above the level of the liquid in the channel. The stretches of the sprocket chains adjacent to the wires or bars are held in substantially straight lines to maintain contact between the scrapers. and the wires.

At the effluent side of the screen, the sheet of wires is supported by rollers pivoted at their ends in sprocket flights so is illustrated in Fig. 1.

stantially semicircular recesses toreceive said wires and This enables a close arrangement of said wires and effective spacing thereof. In the event that wires are displaced in the upper part of the screen, another toothed flight will engage the wires at the bottom of the screen and as it moves upwardly will restore displaced wires to their de-' sired positions. The scraper flights are constructed and positioned to receive and retain the screenings until reaching the upper part of the apparatus where the screenings are removed in any suitable manner and deposited in a chamber for removal from the apparatus.

Other objects, features and advantages will appear upon consideration of the following detailed description and of the drawings in which:

Fig. 1 is a diagrammatic vertical section illustrating one embodiment of the invention;

Fig. '2 is a detail view of part of the trated in Fig. l; and

Fig. 3 is a fragmentary sectional view taken at one edge of a modified form of screen with cooperating parts.

Referring to the drawings, a screen 10 is made up of a sheet of round wires 11 and a base plate 12 to which the lower ends of said wires are secured. This screen 10 is used in a channel 14 through which the liquid to be screened flows from right to left as indicated by the arrow. In the bottom of saidchannel 14 there is a recess 15 extending across the channel. At its influent entrance the bottom of the recess ,15 is a gradually descending plane surface 16. From the forward edge of said plane 16, the bottom of the recess is a circular cylindrical surface 18 extending almost to the level of the bottom of the channel but separated therefrom by a forwardly and upwardly inclined surface 19. As shown in Figs. 1 and 2 the plate 12 is firmly secured to the channel bottom on said inclined surface 19 by suitable means, such as nuts and bolts.

Support of the wires 11 of the screen 10 at their effluent side may be effected by rollers 20 engaging the effluent side of the screen 10.- These rollers are mounted at their opposite ends in sprocket chains 21 which extend around upper sprocket wheels 23 on shaft 24 and lower sprocket wheels 25 on shaft 26. Said shaft 26- is journalled in slidably mounted blocks 27 which can be shifted by screws 28 to adjust the tension of chains 21.

Removal of screenings from the influent side of screen 10 is effected by means of scraper or cleaner flights 30 which engage the influent face of the screen 10. These flights 30 are mounted at their ends on sprocket chains 31 which pass around sprocket wheels 32 on lower shaft 33 and around sprocket wheels 34 on upper shaft 35. Said sprocket chains 31 also pass around tightening pulleys 36. It should be noted that shaft 33 is substantially coaxial with cylindrical surface 18 and that the'flights 30 would carry up to the screen 10 most matter settled in recess or sump 15.

The structure ofa flight 30 is shown most clearly in Fig. 2. Each flight comprises a rake or comb 40 having teeth 41 separated by substantially semi-circular recesses 42 to receive wires 11, and a plate 43 of curved cross-sec tion which receives screenings from screen 10; The scraper structure comprising comb 40 and plate 43 is reinforced by a member 44 of rectangular cross-section. It should be noted that each roller 20 while spaced somewhat to the rear of the corresponding flight 30, tends to hold Wires 11 in recesses 42 of the flight.

The shaft 35 is turned in clockwise direction and shaft 24 in counterclockwise direction by means of a shaft 45 carrying a worm 46 engaging a worm gear 47 on shaft 34 and a reverse pitch worm 48 engaging a worm gear 49 on shaft 24.

Just before a flight 30 reaches the upper sprocket wheels 34, the waste material carried thereby is removed there from to drop into a receptacle 50 having in its lower part a conveying screw 51 to discharge the waste from the apparatus.

One embodiment of means for removing waste from A shaft 52 is mounted in brackets 52' on a fixed supporting member 53 extending acrossv said channel 14. Loosely mounted on shaft .52 are arms54 and in the outer ends of said arms is 'journalled a shaft SScarryinga cylindrical brush 56 for structure illuscleaning flights 30. When the brush 56 is out of action on a flight 30, arms '54 rest on a cross member 57 car' ried by posts 58 mounted on member 53. Shaft 55 is rotated in a clockwise direction by means including a pulley 58 thereon connected by a belt 59 with a pulley 60 fixed on said shaft 52. Shaft 52 in turn is driven by means including a belt 61 connecting apulley 62 on shaft 52 with a pulley 63 on a drive shaft 64.

In order to assure proper operation it is necessary to maintain the lower reaches of chains 21 in straight lines as well as the upper reaches of chains 31. These results may be attained by guiding the lower reaches of sprocket chains 21 by means including inwardly facing channels 65, receiving guide roller-s 65 on sprocket chains 21 and by guiding the upper reaches of sprocket chains 31 by means including inwardly facing channels 66 receiving rollers '66 on sprocket chains 31. Channels 66 may be adjustable on the walls of channel 14 by means comprising mounting screws 67. Channels 65 may be adjusted in a similar manner. The entrance ends of all of the channels are flared to facilitate entrance of corresponding guide rollers 65 or 66.

Passage of the influent liquid between the side edges of the sheet of said wires 11 and the side walls of the channel 14 may be prevented by using a sheet of wires 11 with its side edges close to said side walls. The same effect .may also be attained by use of plates 70 (Fig. 3) extending from the side walls of the channel 14 to the side edges of the sheet of wires in use.

For convenience in assembly andreplacement of parts, thelower ends of said wires 11 are detachably connected to said plate 12. Such connection may be effected by having the lower ends 11 of said wires turned off at uniform angles, here illustrated as right angles, a suitable angle seat to receive said lower ends, and positioning and fastening 'means for the lower ends of said wires. As illustrated in 'Figs. 1 and 2, said angle seat may be formed by placingan angle iron 71 of the proper cross section with one flange 72 resting on the upper surface of plate 12 and extending rearwardly with reference to the direction of flow and the other flange 73 extending upwardly from said plate 12. Said flange 72 is secured to plate 12 in any suitable manner.

Said wires 11 are placed against flange 73 with their offturned lower ends 11 in parallel and resting on the plate 12, and are clamped in position by a plate 74 having a raised part 75 extending over the offturned lower ends 11 of wires 11, and a thicker part 76 resting on-plate 12 and secured thereto. At its rear edge part 75 of plate 74 is provided with notches 77 in which said wires 11 are received. When said plate 74 is clamped to plate 12 by suitable means such as screws 78, wires 11 are held firmly in position.

Wires 11 are obtained in straight lengths and are maintained in this general condition to avoid kinking.

In operation shaft 45 is turned in a direction to drive shaft 35 in clockwise direction and shaft 24 in counterclockwise direction and move flights 30 and flights or rollers along the influent and effluent sides respectively of the sheet of wire 11 'andbeyond the ends of said wires. In this operation as each flight 30 approaches the sheet of wires '11 the teeth 41 enter between wires 11 which then rest in notches 42. The flights or rollers 20 act merely to hold the wires '11 against the combs of flights 30 which serve not only to scrape screenings from the wires but to maintain the wires in spaced relation. Although rollers 20 are shown as plain cylinders, they could well be grooved and serve to assist in maintaining the proper spacing between the wires.

Each flight 30 moves up the influent side of the sheet of wires 11, and during this movement the comb 40 thereof removes screenings from the wires and deposits them on the corresponding curved plate or shelf-43. After passing beyond the upper ends of wires 11, the shelf 43 engages the rotary brush 56 which moves the screenings to the left on said shelf. The brush 56 is then lifted by the shelf 43 and eventually the brush 56 is raised to a dot-and-dash-line position where it rides over the left edge of the shelf and drops to its normal position ready for engagement by the next flight 30.

In riding off a flight 30 there is a tendency for the teeth 41 at the edge of the shell to injure the brush. Such injury might be guarded against in many'ways, for example by means of a wheel (not shown) mounted on the axis of the brush and a projection not shown at the flight edge for engagement by the wheel to separate the brush from the comb.

It will be understood that the screenings can be removed from the flights by other methods and at various points than the one disclosed. In spacing the wires 11, the essential feature is to use flights with teeth spaced to enter between the wires. These teeth may be on front or back flights. There may be a great variety of cross sections of wire. For example, a wire of square cross section might be used either with a flat face fitting in a rectangular notch or with onecorner fitting into a V-notch.

Use of another form of wire is illustrated in Fig. 3. This wire 11a is broad at the influent side of the screen and narrow at the effluent side and is generally of wedgeshape cross-section. With wires of this cross section, the teeth 41a of each flight 30a are narrow and the notches 42a are broad and preferably have fiat bottoms. Also with this form of wire the supporting flights 20a are preferably similar to flights30a and have notches 30b to receive the narrow rear-sides or edges of wires 11a. With wires 11a itwould not be dificult to space the wires from the eflluent side only, that is by using suitable notches 11a in a'flight 20a. Such guiding at the etfluent side of the screen might'also be effective with otherforms of wire screening members.

It should be understood that various changes can be made and that variousfeatures can be used without others, without departing from the true scope and spirit of the invention.

What is claimed is:

1. In a liquid screening apparatus, the combination of a screen comprising a sheet of parallel spaced screen members fixed only at their lower ends, and means for supporting said screen members in a screening relation comprising an endless series of scraper flights extending across the influent face of said screen and confined to travel in a path parallel to the operative position of said screen while passing from the lower area to the top thereof, said scraper flights provided with edges having recesses correlative withsaid screen members to maintain uniform spacing thereof and provide stability on the influent side of sa'id'screen while collecting screenings, and an endless series of support flights extending across the eflluent face of said screen and confined to travel in a path parallel to said screen while passing from the lower area to the upper area thereof .and keep the screen members in said recesses of at least .one or more scraper flights at a time.

2. A liquid screening apparatus according to claim 1 wherein the scraper flights include concave trays to receive the screenings as they are collected, and said trays serve to retain the screenings while said scraper flight moves upward beyond the top edge of said screen where the said screenings are removed.

3. A liquid screening apparatus according to claim 1 wherein said support flights at the eflluent side of said screen are rollers.

4. A liquid screening apparatus according to claim l wherein each series of flights comprises a pair of closed draft chains'rnounted over sprockets at opposite side edges of said screen, the flights of each of said series are mounted between the corresponding pair of chains and secured to the side edges thereof; and fixed channel members adjacent to the side edges of said screen receive a portion of said chains and thereby guide the chains and flights on their upward travel along said screen faces.

5. In a liquid screening apparatus, the combination of a-screen comprising a sheet of parallel spaced screen members fixed only at their lower ends, and means for con tinuously supporting said screenmernbers in a screening relation comprising a pair of closed chains of guides confining opposite sides of said screen to a regular surface while travelling upward therealong from the lower area to the upper area thereof, and the guides of one of said chains having notches correlative with said spaced screen members to maintain uniform spacing and provide stability thereof while screening and removing the screenings therefrom.

6. A liquid screening apparatus according to claim 5 wherein the screen members are fixed at their lower ends by a clamping device comprising a'fixed angular seat having an upstanding face parallel to one face of said screen; the lower ends of the said screen :members are offturned at uniform angles and are placed in parallel in said angular seat; and a clamping device extending over said oflturned ends has notches correlative with said screen members to keep said spacing thereof including means for securing said clamping device to said seat.

7. A liquid screening apparatus according to claim 5 wherein the guides of the influent face of said screen comprise teeth to enter between said screen members to provide stability thereof and also scrape the screenings therefrom and a concave tray to receive screenings scraped from said screen members.

8. A liquid screening apparatus according to claim 7 including means for removingscreenings from said concave trays comprising arms pivoted on an axis at the side of the screen opposite the concave trays, a brush rotatable about a shaft carried by the other ends of said arms, and means for supporting said arms in position for engagement of said brush by the next tray at a position remote fro$ said teeth, the brush riding over the tray and off the tee 9. In a liquid screening apparatus, the combination of a screen comprising a sheet of parallel spaced screen members fixed only at their lower ends, and means for supporting said screen members in a screening relation comprising an endless series of scraper flights extending across the influent face of said screen and confined to travel in a path parallel to the operative position of said screen while passing from the lower area to the top thereof, an endless series of guide flights extending across the effluent face of said screen and confined to travel in a path parallel to said screen while passing from the lower area to the upper area thereof, and means for maintaining uniform spacing of said screen members comprising notches in said guide flights correlative with said spaced screen members and both said series of flights arranged so that the said screen members are confined to said notches of at least one or more guide flights at a time by cooperation of said series of scraper flights.

10. In a liquid screening apparatus, the combination of a screen comprising a sheet of parallel spaced screen wires fixed only at their lower ends, means for supporting said screen wires in a screening relation comprising an endless series of scraper flights extending across the influent face of said screen and confined to travel in a path parallel to the operative position of said screen while passing from the lower area to a point above the top thereof, said scraper flights provided with edges having recesses correlative with said screen wires to maintain uniform spacing thereof and provide stability on the influent side of said screen while the backs of said flights have concave trays for collecting screenings, an endless series of support flights extending across the efiiuent face of said screen and confined to travel in a path parallel to said screen While passing from the lower area to the upper area thereof and keep the screen wires in said recesses of at least one or more scraper flights at a time and means for driving said flights.

11. A liquid screening apparatus according to claim 10 wherein said support flights at the effluent side of said screen are rollers.

12. A liquid screening apparatus according to claim 10 wherein each series of flights comprises a pair of closed draft chains mounted over sprockets at opposite side edges of said screen, the flights of each of said series are mounted between the corresponding pair of chains and secured to the side edges thereof; and fixed channel members adjacent to the side edges of said screen receive a portion of said chains and thereby guide the chains and flights on their upward travel along said screen faces.

13. A liquid screening apparatus according to claim 10 including means for removing screenings from said scraper flights comprising arms pivoted on an axis at the side of the screen opposite said scraper flights, a brush rotatable about a shaft carried by the other ends of said arms, and means for supporting said arms in position for engagement of said brush by the next flight at a position remote from said teeth, the brush riding over the flight and off the teeth.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,180,798 Spoon Apr. 25, 1916 1,615,559 Tark Jan. 25, 1927 1,881,270 Evers et al. Oct. 4, 1932 1,940,952 Hutchens Dec. 26, 1933 2,090,637 Paige Aug. 24, 1937 2,128,345 Briggs Aug. 30, 1938 2,199,788 Durdin May 17, 1940 2,358,841 Walker Sept. 26, 1944 FOREIGN PATENTS Number Country Date 148,021 Germany Dec. 6, 1901

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