BACKGROUND OF THE INVENTION

This invention deals with rotary screens used in rotary screening devices for cleaning water .

Such rotary screening devices are also known as Trommel screens . Rotary screening devices are mechanical screening machines used to separate materials , mainly in the mineral and solid-waste processing industries . They consist of a perforated cylindrical drum or mesh screen that is normally elevated at an angle at the feed end .

Physical size separation is achieved as the feed material spirals down the rotating drum or screen, sometimes assisted by augers or conveyors , or the like , where the undersized material smaller than the mesh or apertures passes through the screen, while the oversized material exits at the other end of the drum .

In the wastewater treatment industry, the solids that exit the rotary screen normally are compressed and dewatered as they travel along the conveyor or rotary auger . Most often a post-washing treatment such as a j et wash will be used after the rotary screen to break down fecal matter and unwanted semi-solid matter . The volume of the solids will decrease up to 40% depending on the properties before removal . Rotary screens come in many designs such as concentric screens , series or parallel arrangement and each component has a few configurations . Rotary screening devices are used by the municipal waste industry in the screening process to classify sizes of solid waste . In addition, rotary screening devices are used for the treatment of water . For this particular application, solids from the entering stream will settle onto the screen mesh and the drum will rotate once the liquid reaches a certain level . The clean area of the screen is submerged into the liquid while the trapped solids fall onto a conveyor or auger which is further processed before removal .

THE INVENTION

This invention deals with rotary screens used in rotary screening devices for cleaning water in which the prior art trunnion wheels on current state of the art rotary screening devices are substituted by a rocker shoe and a bearing running on the rocker shoe .

Thus , what is disclosed in this specification and claims is a rotary screening device for cleaning water . The rotary screening device comprises a housing, wherein the housing contains a rotary screen . The rotary screen provides separation of particulate solid matter from water .

The rotary screen is powered at a first end by a motor and gear box, while the second end rotates on a rocker shoe . The second end outside surface supports a bearing, wherein the bearing is lubricated by water . The bearing contacts the rocker shoe .

There is a system for delivering water to the bearing while the bearing is in use . The rotary screen further comprises a spray bar for providing cleaning water to the outside surface of the rotary screen .

There is a water system for delivering water to the spray bar and an inlet for supplying and distributing uncleaned water to the interior of the rotary screen . There is a water exit from the housing and a solids outlet from the rotary screen . BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a segment end view of a prior art rotary screening device showing the prior art trunnion wheel on one end of the rotary screening device .

Figure 2 is a full side view of one version of the instant invention, a rotary screening device with a bearing .

Figure 3 is a cross-sectional of the device of Figure 2 through line A-A of Figure 2 .

Figure 4 is a segment view of the bearing and rocker arm of the instant invention .

Figure 5 is a segment of the bearing showing the spray lubrication . DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a segmental view of a prior art rotary screen device in which there is shown the use of trunnion rollers 19 . This is shown to indicate the prior art use of such devices in comparison to the instant invention in which the trunnion rollers 19 have been replaced by a rocker shoe and a bearing ( described in detail infra ) .

Turning to Figure 2 , there is shown a device of this invention which is a rotary screen device 1 . It is equipped with a motor and gear box 2 , an inlet 3 for the aqueous material to be treated, an outlet 4 for the solids removed from the aqueous media, a support stand 5 for supporting the rotary screen device 1 , a clean water inlet 6 , a housing 7 , and at the lower end of the housing 7 there is shown bearings 9 , on the outside surface of the housing 7 and a rocker shoe 10 with a bearing 11 ( shown in phantom) near the bottom edge 12 thereof .

It is contemplated with the scope of this invention to manufacture the device 1 such that the inlet 6 is on the opposite end of the housing 7 .

Figure 3 is a cross sectional view through line A-A of Figure 1 , showing the additional components of the device 1 . There is shown a motor and gear box 2 , an inlet 3 for the aqueous material to be treated, an outlet 4 for the solids removed from the aqueous media , a support stand 5 for supporting the rotary screen device 1 , a clean water inlet 6 , and a housing 7 . Also shown is the rotary screen 8 and the rocker shoe 10 along with the bearing 11 near the bottom edge 12 thereof ( shown in phantom) . The drawings show a narrow gap between the bearing 9 and the rocker shoe 10 for clarity purposes . In working order , the surface of the bearing 9 rides on the inside surface of the rocker shoe 10 . See also Figure 4 .

The bearing on the rotary screen can be manufactured from plastics , metal , such as stainless steel , ceramics , and the like .

Any plastic used in the plastic bearing can be such materials as Thordon or Vesconite brand bearing materials available from Thordon Bearings Inc . Burlington, Ontario , Canada , ultra-high molecular weight polyethylene , high density polyethylene or c ross-linked polyethylene .

There is a plurality of sprayers 13 located above the roller screen 8 to cleanse the roller screen . Water for this purpose is introduced at the freshwater inlet 14 . The detail in the sprayers 14 is shown in Figure 5 , wherein there is shown the sprayers 14 , the freshwater inlet tube 15 , the roller screen 8 , and the bearing 9 . Shown in Figure 5 is the furnishing of water to the bearing 9 , but the bearing 9 is also furnished water as a lubricant at the inlet port 16 shown in Figure 2 .

Figure 4 is a detail of the rocker shoe 10 and the bearing 10 along with the bearing 11 and a steel pin 17 to support the bearing 11 .

It should be noted that the exact placement of the various components on the rotary screen device is not critical except for the placement of the rocker shoe and the bearing .