US1740578A

US1740578A - Sigmieejsts

Info

Publication number: US1740578A
Authority: US
Publication date: 1929-12-24
Anticipated expiration: 1946-12-24

Description

Dec; 24, 1929. L UE 1,740,578

SCREEN Filed Aug. 1, 1923 2 Sheets-Sheet l I: m 3/ M 1 ATTORNEYS.

Dec. 24, 1929. w. L. DOLIER SCREEN Filed Aug. 1, 1925 2 Sheets-Sheet 2 Fatented Dec. 214, 192% onrrao OFFICE WILLIAM L. DOLIER, OF PHILADELIPH, PENNSYLVANIA, ASSIGNOR, BY MESNE AS- SIGNEEENTS, 1'0 0. GRAY AND JOHN SCI-BEAM, BOTH OF BUFFALO, NEW YORK, AND W. G. JPEUCHEN, OF NORTH TONAWANDA, NEW YORK 1 sonnnn Application filed August 1, 1923.

My present invention relates to screens particularly adapted for the screening of sewage and the like, and will be best understood from the following description and the an- ;nexed drawings, in which Fig. 1 is a sectional elevation of an illustrative type of screen, which in this case is the well-known Riensch- Wurl screen, a typical arrangement of which is shown in the patent to Stephens No. 1,264,- 990; Fig. 2 is a plan view of Fig. 1, with parts of the pit walls broken away; Fig. 3 is an en- 'larged section on the line 3-3 of Fig. 2, and Fig. 4 is an enlarged section of a portion of Fig. 1.

Like reference characters indicate like parts in the several views.

In the illustrative arrangement, the screen has a disc portion indicated generally at 10 and a conical portion indicated generally at '11. The screen is formed of a suitable framework supporting screening plates to be described more specifically hereinafter and is supported on a shaft 12 inclined to the horizontal and supported in bearings in a wellknown manner. The screen is mounted in a pit 13 having an inlet conduit 14 and outlet 15, the inlet and outlet being on opposite sides of the screen. By reason of the tilting of the screen, its lowermost portion will be submerged in the fluid being treated and its upper portion well out of such fluid. Brushes are provided on the portion out of the fluid to clean the same as the screen in rotated. One set of brushes 16 mounted on arms 17 carried by the shaft 18 serve to clean the disc portion 10 and a brush 18 serves to clean the conical portion 11. The brushes are drivenin any suitable manner, the brush 18 being located in relation to the direction of rotation of the screen 10, so that the solids removed from the none 11- will fall on the disc 10 in the path of the brushes 16. The axis 18 of the brushes 16 is located relatively close to the periphery of the'disc 10, so that the brushes 16 pass over this disc on a relatively short radius.

The screening surface of the disc portion 10 is made up of a plurality of plates 19, each wedge-shaped, with their edges extendingin radial lines on the disc 10 and preferably the plates are held on the disc by clamping strips Serial No. 655,004.

20 held to the frame by screws 21, (see Fig. 3) the edges of the plates 19, in the illustrative embodiment, being bevelled to cooperate with correspondingly bevelled edges of the clamping strip 20, to hold the plates in position without necessitating screw holes or the like in the plates 19. In order to prevent undue wear on the brushes, T preferably make the clamping strips 20 flush with the tops of the plates 19.

The screening openings in the plates 19 are relatively long and narrow slots and it is desirable that these slots be arranged so that the brushes 16 will move lengthwise of the slots in order to keep the slots clean and free from solids. To this end, T divide each plate 19 into three zones and form the slots 22 parallel to the radial center line of the plate 19 and the slots 23 in the zone nearest the axis of the screen at right-angles to this center line. The middle zone has its slots 24 positioned at an angle to this center line, preferably at With the

slots

22, 23 and 24 formed in this manner, it will be seen by an inspection of Fig. 2 that as a brush 16, turning clockwise around its shaft 18 passes over the outer zone, it will be moving substantially parallel to the slots 22, and similarly as it passes off the disc 10, it will be moved parallel to these slots. As a brush 16 is moving in the portion of its are nearest the center of the screen, it will move substantially at right-angles to the radius of the screen and will, therefore, be moving substantially parallel to the slots 23. As the brush passes from the inner zone as it is leaving the screen, it will be passing approximately at 45 to a radial line on the screen and, therefore, by extending the slots 24 at an angle of approximately 45 to this radial line, the brush 16 will be moving substant1ally lengthwise of the slots 24. c

As shown best in Fig. 2, the brush 16 will be moving across the slots 24 in a difierent direction when approaching the center of the screen than when moving away from such center, and for that reason, T position the slots, 24 as shown in Fig. 1, so that the brush 16 will be moving substantially parallel .to these slots as it is moving toward the periphery of the screen, because at that time the 2 brush 16 is removing substantially all of the solids carried up by the disc 10 and also delivered to the disc 10 by the cone brush 18.

1 The disc 10 is surrounded in the portion which is submerged in the fluid to be treated by a fixed wall to compel the fluid to pass through the screen, and it is preferred to attech to this wall a circular channel'25. A segmental screen seal 26 is adjustably carried on said channel and it is desirable that the screen plates 19 shall be spaced only a very small distance from the edge of the seal 26. It is diflicult to maintain the exact clearance space between the edges of the plates 19 and the seal 26, and any inaccuracy in the screen or its bearings may cause the edges of the plates 19 to wear and increase the space through which fluid may pass without-passing through the screen. Such wear would ultimately require the removal and replacement of the plates 19, and in order to avoid this expensive replacement, I stop the plates 19 short of the edge of the frame of the screen and interpose between the ends of the plates 19 and the seal 26, circular wear pieces 27 removabl attached to the frame of the screen and fl iish with the tops of the plates 19. Consequently, if for any reason the edges of the wear pieces 27 become Worn, one or more of such segments may be removed and replaced to remedy the dificulty Without necessitating the replacement of the screen plates'19. p

The eflectiveness of a screen for removing solids from a fluid is increased if the screen plates are covered with some of the solids being screened, such layer of solids serving to retain more solids than the screen plates themselves. When the screen in the illustrative embodiment is operating with a full flow of fluid through the inlet 14, the level thereof would be nearly at the top .of the conical portion 11. A cleaned portion of the screen entering the fluid in the pit 13 is almost immediately cover d with a layer of solids and this layer serv e s to act as a screening matduring the motion of its travel through the fluid in the pit. If, however, the flow of fluid through the inlet 14 is lowered to a point where onl a small portion of the screen is submerge it will be evident that the solids will not cover any substantial part of the screen, so that the screening will not be as effective as if the level of the fluidin the pit 1.3 on the inlet side thereof were at a much higher point. This falling off in flow is liable to occur in sewage operations at night.

To obviate this difficulty, I provide means to control the rotation of the screen when the rate of flow through the inlet l4 is not sufficient to submerge a considerable portion of the screen. In the illustrative embodiment, I provide a switch 28 controlling the current to the motor 29 which rotates the screen and the brushes (I operate this switch means .position of the parts shown in Fig. 1. This would occur when the rate of flow through the inlet 14 is insuificie'nt to maintain the float 30 at a higher position.

As soon as the I rotation of the screen is stopped, the incoming fluid will deposit solids on the lower part of the screen and gradually build up a barrier to the fluid to raise the level thereof in the inlet side of the pit, and correspondingly gradually raise thefioat 30, the layer of solids deposited on the stationary screen serving in the meantime to thoroughly screen the liquid passing through. When the float 30 has been raised to a desired point, as, for instance, when the level of the fluid on the inlet side approaches the top of the conical portion 11, the member 34 will contact with the other end of the switch arm 33 to throw the switch 38 to supply current to themotor 29 and to begin the rotation of the screen. Then as more liquid will pass through the screen than is entering at the inlet 14, the level in the inlet side of the pit will again fall and again bring the screen to rest when the level has dropped to a predetermined point.

By the means described, I provide an arrangement by which the liquid will be substantially as efl'ectively screened when a small quantity is flowing as when the inlet 14 is entirely filled.

' It will be understood that the conical portion 11 of the screen is made up of plates in the usual manner to a large extent. I prefer, however, to hold the cone plates in position on the screen cone frame by clamping strips 20 in a manner similar to the use and function of clamping strips 20.

In attaching the wear plates 27 and the plates 19 to the frame, the means shown in Fig. 4 may be used, or the inner under edge of the wear plates 27 may be bevelled and the outer upper edge of the plates bevelled and the

plates

27 and 19 overla ped' so that the screws in the wear plates 27 will act to hold the plates 19 in place also. The principle above described is shown in Fig. 3 where the binder strips 20 hold the plates 19 on the radial joints.

While I have illustrated my arrangement in connection with a disc screen having a conical portion, it will be understood that ,many features thereof may be applied to ment of my invention may be widely varied from the illustrative arrangement which I have shown in the drawings.

I claim:

1. In combination, a rotary disc screen and brushes arranged to move parallel with and across the surface of the disc in an arc having its center outside of and relatively close to the periphery of the disc, said screen being provided with relatively long and narrow screening slots arranged in three groups as to the direction of the slots, the group nearest the periphery of the disc extending substantially radially to the disc, the group nearest the axis of the disc extending substantially circumferentially of the disc and the middle group extending substantially at 45 to the radius of the disc.

2. In combination, a rotary disc screen and brushes arranged to move parallel with and across the surface of the disc in an arc having its center outside of and relatively close to the periphery of the disc, said disc being made up of a plurality of wedge-shaped screening plates with the large ends of the plates at the periphery of the disc, each of said plates having relatively long and narrow screening slots arranged in three groups, with the group at the large end of the plate extending parallel to the radial center line of the plate, and the group at the small end of the plate extending at right-angles to said center line and the middle group extending at an angle to said center line.

3. In combination, a rotary disc screen and brushes arranged to move parallel with and across the surface of the disc in an arc having its center outside of and relatively close to the periphery of the disc, and means to rotate said screen and said brushes in directions to cause the brushes to move in a general direction opposite to the portion of the disc with which they cooperate, said screen being provided with relatively long and narrow screening slots arranged in three groups, the

group nearest the periphery of the disc extending substantially radially to the disc,

the group nearest the axis'of the disc extending substantially circumferentially of the disc and the middle group extending substantially at an angle to the radius of the screen corresponding to the direction of motion of the brushes as they are passing over such slots from the center toward the periphery of the disc;

4. In combination, a rotary circular screen having a frame and a plurality of screen plates detachably mounted on said frame, each of said plates being wedge-shaped with the large end of the plate at the periphery of the screen, and a wearing strip attached to said frame and extending along the large ends of said screen plates.

5. In combination, a rotary pircular screen having a frame and a plurality of screen plates detachably mounted on said frame, each of said plates being wedge-shaped with the large end of the plate at the periphery of the screen, and a clamping strip attached to said frame and extending over the edges of each pair of adjacent plates and arranged to hold said plates to the frame, the edges of adjacent plates being spaced apart with the clamping strip in the space between the edges.

6. In combination, a rotary circular screen having a frame and a plurality of screen plates detachably mounted on said frame, each of said plates being wedge-shaped with the large end of the plate at the periphery of the screen, and a clamping strip attached to said frame and extending over the edges of each pair of adjacent plates and arranged to hold said plates to the frame, the edges of adjacent plates being spaced apart with the clamping strip in the space between the edges and the top of the clamping strip being not higher than the surfaces of the plates.

7. In combination, a rotary circular screen having a frame and a plurality of screen plates detachably mounted on'said frame, each of said plates being wedge-shaped with the large end of the plate at the periphery of the screen, and a clamping strip attached to said frame and extending over the edges of each pair of adjacent plates and arranged to hold said plates to the frame, the edges of adjacent plates being spaced apart with the clamping strip and the space between the edges.

8. In combination, a rotary disc screen having a frame and a plurality of screen plates detachably mounted on said frame, a wall surrounding a portion of the periphery of said disc with the edge of the disc closely adjacent the wall, and a circular wear piece at the periphery of the disc.

9. In combination, a rotary disc screen having a frame and a plurality of screen plates detachably mounted on said frame, a wall surrounding a portion of the periphery of said disc with the edge of the disc closely adjacent the wall, and a circular wear piece at the periphery of the disc and divided into segments detachably connected to the frame.

10. In combination, a rotary disc screen having a frame and a plurality of screen plates detachably mounted on said frame. a wall surrounding a portion of the periphery of said disc with the edge of the disc closely adjacent the wall, and a circular Wear piece at the periphery of the disc and divided into segments detachably connected to the frame, said Wear piece beingrof the same thickness as the plates and extending beyond the edge of the frame.

'WILLIAM L. DOLIER.