US20150027943A1

US20150027943A1 - Rake screen and novel components therefor

Info

Publication number: US20150027943A1
Application number: US14/326,548
Authority: US
Inventors: Tammy Bernier; Steven Dill; Terry Duperon; Michael A. Woodley; Kenneth S. Blanchard; Daniel A. Courser, JR.; Bryce Funchion; Janet K. LaFave
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-07-09
Filing date: 2014-07-09
Publication date: 2015-01-29
Also published as: US20230330571A1; US11617976B2; US11577185B2; US20170209819A1; US20220410043A1

Abstract

Rake systems for cleaning water streams and new and novel components for such rake systems.

Description

This application is a utility application claiming priority from U.S. provisional application Ser. No. 61/843,948, filed Jul. 9, 2013.
The invention disclosed and claimed herein deals with rake systems for cleaning water streams and new and novel components for such rake systems.
“Rake screens” (flex rakes) as used herein means those apparati that are used to remove particulates and solid materials from moving streams of water and include at least those apparati disclosed in U.S. Pat. No. 4,709,804, that issued Dec. 1, 1987 and U.S. Pat. No. 5,425,875, that issued on Jun. 20, 1995, and U.S Patent publication 2011/0049039 A1, that published on Mar. 3, 2011.

BACKGROUND OF THE INVENTION

This application deals with an apparatus for removing debris from water containing such debris. Such apparati are found generally in wastewater clean-up situations for example, in municipal sewage systems and the like.
There are several patents directed to such apparati and among them are the patents set forth just above, which disclose the most modern technologies available for such water clean-up.
U.S. Pat. No. 4,709,004 to Duperon, that issued on Dec. 1, 1987, is an earlier disclosure of a self-cleaning trash rack that includes an upright frame positioned in the path of trash carried by the stream and a plurality of endless, flexible chains carrying trash supports which engage and carry debris on the upstream side of the frame upwardly for disposal.
A more modern version can be found in U.S. Pat. No. 5,425,875, that issued to Duperon on Jun. 20, 1995 in which there is disclosed an upper turning drum and a pair of chains trained about the drum and carrying scraper blades which engage and carry debris on the upstream side of the rack upwardly for disposal. The novelty of that disclosure is the drive mechanism using a new type of chain.
Further, there is U.S. patent Publication 2011/0049039 to Duperon, at al, that deals with an apparatus for removing debris from water containing such debris using a perforated plate, a backer plate, and a skimmer, positioned adjacent the back of the perforated plate to provide a means of removing debris from the perforated plate without scraping the debris from the perforated plate, the skimmer bar and the backer plate being synchronized in their movement.
All of the above incorporated herein by reference for what they teach about flex rakes and their construction.
Additional patents of interest to show other mechanisms and components are: U.S. Pat. No. 6,869,524, that issued on Mar. 22, 2005 to Seidl; U.S. Pat. No. 7,776,212, that issued on Aug. 17, 2010 to Wunsch, at al.; U.S. Pat. No. 5,618,415, that issued Apr. 8, 1997 to Johnson; U.S. Pat. No. 7,575,674, that issued to Chang on Aug. 18, 2009; U.S. Pat. No. 7,300,572, that issued on Nov. 27, 2007 to DePaso, at al.; U.S. Pat. No. 7,048,850, that issued on May 23, 2006 to DePaso, at al.; U.S. Pat. No. 7,722,762, that issued on May 25, 2010 to Zubair; U.S. Pat. No. 7,393,451 that issued on Jul. 1, 2008 to Wunsch, at al.; U.S. Pat. No. 6,294,085, that issued on Sep. 25, 2001 to Bache; U.S. Pat. No. 4,186,091, that issued Jan. 29, 1980 to Sutton; U.S. Pat. No. 3,731,814, that issued May 8, 1973 to Walters, and U.S. Pat. No. 2,751,087, that issued to Wallquist on Jun. 19, 1956.

SUMMARY OF THE INVENTION

What is disclosed end claimed herein are apparati and novel component parts for removing debris from water. Novel component parts include among other, dual wiper blades, flexing apparatus for moving the chain of the chain drive of the apparatus, whenever large materials are carried on the skimmers, pivotal drive head that works in conjunction with the flexing apparatus if both are installed on the apparatus, and a pivoting closure cap, rotating effector plates, along with modules of each of these novel components, in addition to a novel secondary skimmer device useful with primary skimming devices.

THE INVENTION

In a first embodiment, there a component part which is a flexing apparatus for a flex rake. The flexing apparatus comprises a pair of elongated rails, each rail having a top end, a bottom end, a first attachment point and a second attachment point.
The first attachment point is located near the top end of each of the elongated rails, and each second attachment point is located near the bottom end of each elongated rail. An attached support arm is attached at each attachment point, and each of the support arms has a distal end.
Attached to each support arm distal end, is a means for enhancing the movement of a chain and the bottom end and top end of each elongated rail has a means for enhancing the movement of a chain incorporated in it.
There is a secondary pivotally mounted second roller in each of the elongated rail, near each of the top end second rollers.
A second embodiment of this invention is a rake screen apparatus having a flexing apparatus of mounted to a framework of the rake screen apparatus.
A third embodiment of this invention is a component part which is a dual wiper blade assembly for a rake system. The dual wiper blade assembly comprises a pair of support members each having a near end and a distal end, wherein each near end has a pivotal attachment capability for attaching to a framework of a rake system. The distal end of the support member has attached to it, holders, wherein each holder has a bottom edge.
Each bottom edge has a first notch in it and a spaced-apart second notch in it. There is a common first wiper blade attached in the first notches and a common second wipe blade surmounting the first wiper blade and attached in the second notches.
A fourth embodiment of this invention is a rake screen apparatus having a dual wiper blade assembly as set forth just Supra, mounted to a framework of the rake screen apparatus.
A fifth embodiment of this invention is a stand-alone modular unit comprising a bar screen, the modular unit configured to replace a bar screen in an existing rake screen apparatus.
In addition, there is an embodiment which is a stand-alone modular unit comprising a perforated plate assembly, wherein the modular unit is configured to replace a perforated plate assembly or bar screen in an existing rake screen apparatus.
An additional embodiment of this invention is a component which is a pivoting drive head apparatus for a rake screen. The pivoting drive head comprises a pair of spaced-apart, parallel support members, each parallel spaced-apart member having a near end, a distal end and a middle portion.
Each near end is pivotally attachable to a framework of a rake screen and each parallel support member is pivotally attached to a drive sprocket, wherein each drive sprocket is mounted on the ends of a common drive shaft therebetween. Each drive sprocket is attached to each respective parallel support member near the middle portion of the parallel support member. Each distal end of the parallel support member are configured as a stop foot. Each parallel support member, each sprocket and the common drive shaft are pivotable away from the rake screen framework.
Still further, there is an embodiment which is a rake screen apparatus having a pivoting drive head apparatus mounted to a framework of said rake screen apparatus. In addition, this arrangement can also have a flexing apparatus incorporated into the rake screen. The rake screen apparatus can have a fixed drive head and a flexing apparatus in combination.
Yet, there is another embodiment of this invention which is a component which is a pivoting closure cap for a rake screen apparatus having side framework. The pivoting closure cap comprises a top panel, two mirror image side panels having edges and, top front corners, which is attached at the edges to the top panel. There is a back panel having edges and attached at the edges to the top panel and the side panels.
Each side panel is configured to accommodate any components extending beyond the side panels such that the components will not interfere with closure of the pivoting closure cap. There is a flexing enclosure lid, pivotably mounted at the top front corners of the side panels.
A sixth embodiment of this invention is a combination of a rake screen apparatus and a pivoting closing cap as set forth just Supra, in which the pivoting closing cap is mounted to the framework of the rake screen apparatus.
Further, there is an embodiment which is a rake screen apparatus containing in addition, in combination, a flexing apparatus, a dual wiper blade assembly, a pivoting drive head apparatus, a pivoting closure cap, a revolving effector plate apparatus, and a secondary skimming device that follows after the primary skimming device.
A seventh embodiment of this invention is a rake screen apparatus in which screens, drive mechanisms and enclosures are all modular, wherein each of the screens, drive mechanisms and enclosures can be removed or replaced without disassembling the entire rake screen apparatus.
An eighth embodiment of this invention are the modular components, for example, a screen module, a drive module containing a drive and a skimmer system, an enclosure module that has the ability to be modified to create clearance for various size debris moving through a rake screen, and a modular component for a rake screen that is a flexing apparatus, a rotational effector plate, along with a secondary skimming device.
A final embodiment of this invention is a rotational, moveable, effector module for use with a trash rake. The rotational, moveable, effector module comprises a frame, wherein the frame has a top end, and bottom end, and two sides.
There is a first common axle extending between the two sides near the top end and a second common axle extending between the two sides and located beneath the first common axle. The first common axle and the second common axle are driveably connected by a common drive assembly. The second common axle has a sprocket located at each end, each sprocket having a drive chain located on it, the chains having a lower end. The chains are not mounted on a sprocket at the lower end.
There is a plurality of cross members equally spaced between the chains and each cross member has mounted on it, skimmers. Each skimmer interfaces with a backside of a perforated plate filtration screen of a trash rack, and each shimmer has a leading edge.
Optionally, the leading edge of each primary skimmer in a flex rake has a thin, flexible sheet attached to it in a manner sufficient to apply a low, consistent force along a leading edge of the thin, flexible sheet, against a surface of a perforated screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a full side view of a prior art flex rake for cleaning debris from water.

FIG. 2A is a full side view of a flexing apparatus of this invention mounted within a flex rake, inside the chain, in a normal operating position, wherein the drive head is stationary.

FIG. 2B is a full side view of a flexing apparatus of FIG. 1A wherein the flexing apparatus is in a flex position wherein the drive head is stationary.

FIG. 2C is an enlarged full side view of a flexing apparatus of FIG. 1A showing detail of the mounting.

FIG. 3A is an isometric view of the dual wiper blade mounted on the flex rake apparatus.

FIG. 3B is a full side view of the dual wiper blade apparatus mounted on the flex rake apparatus.

FIG. 3C is a full back view of the dual wiper blade apparatus mounted on the flex rake apparatus.

FIGS. 3D to 3H illustrate the progressive movement of the dual wiper blades across the skimmer moving from left to right.

FIG. 4A is a full side view of the mounting apparatus for the pivotal drive head showing the normal operating position of the drive head.

FIG. 4B is a full side view of the mounting apparatus for the pivotal drive head showing the pivoted position when a large object is encountered on the skimmer blade.

FIG. 4C is a full front view of the mounting apparati for the pivotal drive head.

FIG. 4D is an isometric view of the mounting apparati for the pivotal drive head.

FIG. 4E is a full side view of the mounting apparati for the pivotal drive head.

FIG. 5A shows a view in perspective from the front of a screen module.

FIG. 5B shows a full side view of the screen module.

FIG. 5C shows a full view in perspective from the back of a drive module and flexing component.

FIG. 5D is a full side view of the drive module and flexing component of FIG. 5C.

FIG. 5E is a full view in perspective of the enclosure module of this invention.

FIG. 5F is a full side view of the enclosure module of FIG. 5E.

FIG. 5G is a full view in perspective from the front of the flex rake showing a bar screen module.

FIG. 5H is a full view in perspective from the front of the flex rake showing an effector module.

FIG. 5I is a full back view of an effector module showing the water system and other components.

FIG. 6A is a full side view of the normal operating position of the enclosure cap.

FIG. 6B is a full side view of the pivot out position of the enclosure cap of FIG. 6A.

FIG. 6C is a full side view of the pivoting position for inspection of the interior of the enclosure cap and the pivot head.

FIG. 7 is a full view in perspective from the front, of a primary skimmer bar showing the skimmers.

FIG. 8 is an enlarged primary skimmer showing the secondary skimmers in place.

FIG. 9 is a full view in perspective of the plate with attached secondary skimmer that is used to mount the secondary skimmer on the primary skimmer.

DETAILED DESCRIPTION OF THE INVENTION

Turning tow to the detailed description of the invention, there is shown in FIG. 1, a prior art flex rake apparatus 1 having a thin plate apparatus for removing debris from water. The purpose of inclusion of this in the disclosure is to show the conventional parts of such an apparatus.
There is shown in FIG. 2A, which is a schematic of the internal apparatus of a flex rake, the first novel component of this invention which is the flex bar 2 used in conjunction with the pivotal head 8 of the flex rake to move the drive chain 3 out of line with regard to any large object 4 (FIG. 2B) that is brought from the water to the surface for disposal and at the same time, maintaining the skimmers 5 in position near the screen 6. The large object 4 has a tendency to obstruct the apparatus and make it ineffective for the work that it is supposed to do. FIG. 2A shows the normal position of the chain 3, and FIG. 2 b shows the chain 3 in a flexed position. FIG. 2C is an enlarged Figure to shown the mounting 10 of the lower flex bar apparatus 2.
When the flex rake is installed at 30 degrees from vertical, two mechanisms accomplish this. First, the weight of the chain 3 and skimmers 5 leaning at 30 degrees along the surface of the screen 6 along with the flexing capability of the flex links 7 of the chain 3 creates skimmer contact with the screen 6 along with the ability to flex away for larger debris. The second feature that creates this functionality at 30 degrees is the hanging drive head (pivotal drive head) 8, Figure FIGS. 4A to 4E. The pivotal drive head 8 and the drive sprocket 9 swing out of the way (See FIG. 4B) when large debris moves up to the top of the screen 6. In a vertical or near vertical application, this functionality is lost. At vertical or near vertical, the skimmers 5 do not push up against the screen 6, but instead they hang freely from the drive sprocket 9. This creates a problem because without the pressure of the skimmers 5 to the screen 6, debris can get between the skimmers 5 and the screen 6 and fall back down into the water channel.
In order to create this functionality at all angles including vertical, the inventors herein have created a novel invention that gives the same functionality at all angles. The pivotal head 8, the drive sprocket 9, and the flex bar 2 are attached to the structure of the machine in such a way that they pivot to engage with the chain 3 in order to apply pressure to the skimmers 5 into the screen 6 while still allowing the chain links 7 to flex away from the screen 6 by pivoting out of the way.
This apparatus can be used in flex rakes having fixed drive heads, as well as pivotable drive heads. In prior apparati, the drive heads were not fixed, that is, they had to be pivotable in order to pass the obstructions provided by large objects. Now, there is a means of using fixed heads in such apparati. This component allows the flex rake to be used essentially vertically, or it can allow the flex rake to be used on an angle relative to vertical.
The pivotal drive heads 8 of this invention are also novel, in that, the same functionality can be had in all configurations of the flex rake. The pivoting drive head 8 can be used without the flexing apparatus in flex rakes installed at 15 degrees from vertical or higher. The flexible chain links 7 function by holding pressure to the screen 6 using the weight of the chain links 7 and skimmers 5, then flexing out of the way for large debris 4 when the large debris 4 gets to the top of the screen. Instead of the drive head 8 swinging out of the way with the anchor points above the drive head 8, it pivots out of the way with the anchor points below the drive head 8. The pivoting drive head 8 can also be used in applications installed at 0 to 15 degrees in conjunction with the flexing apparatus.
Turning now to the duel wiping blades 11 of this invention, there are several known debris blades currently in use, however, they are single wiper blade apparati. One of the largest problems in the industry with cleaning skimmers 5 is the fact that they may not completely clean each skimmer or wipe the wrapped “rags” off when they swipe the skimmers 5. The novel duel blades 11 of this invention wipe each skimmer 5 twice each time that the skimmer 5 passes this cleaning mechanism. This ensures that debris is cleaned off the skimmer 5 by fully wiping the skimmer 5 at least two times. See FIGS. 3A to 3H.
The enclosure cap 12 of this invention is designed to cover the top of the flex rake and its top most components (See FIG. 6B). The enclosure cap 12 of this invention is also designed to allow the enclosure cap 12 to pivot out of the way (See FIG. 6B) when a large object 4 arrives at the top of the mechanism. In addition, the enclosure cap 12 of this invention will open widely to allow for the inspection and removal of debris that may become jammed in the apparatus (See FIG. 6C).
A very novel feature of this invention is the modularity that is built into the flex rake. The newest versions of the flex rake that are covered by this invention are designed in modules such that each section of the machine houses different components. The flex rake has a screen module 13, FIGS. 5A and 5B, a drive module 14, FIGS. 5C and 5D, an enclosure module 15, FIGS. 5E and 5F, and an effector module 16, FIG. 5H and a portion of an effector module 5I, and also the ability to add different modules to the flex rake. Each section can be used or exchanged to accommodate various functionalities as needed. FIG. 5G shows the drive module 14 and screen module 13 in combination. FIG. 5H shows a combination of a drive module 14, a screen module 13 and an effector module 16 in combination.
For example, in order to modify a ¼ inch teardrop bar screen 17 as shown in FIG. 5G, to a ¾ inch teardrop bar screen the only module affected would be the screen module 13. The drive module 14 and enclosure module 15 would remain the same. This modularity allows for greater flexibility in design and functionality for the new flex rake equipment. The new equipment could have a ¼ inch teardrop bar screen that has been unchanged except for the screen module that has been changed to a ¾ inch teardrop bar screen. If a customer had this need the flex rake can be adapted to that need without replacing the whole piece of equipment.
The invention herein has another novel feature, and that is the capability of not only replacing individual modules, but also to add modules as necessary to increase or change the functionality of the flex rake.
With reference to FIGS. 5G and 5H, there is shown a machine with a ¼ inch teardrop screen in the screen section that is replaced by a 2 mm perforated screen 6 for that section (FIG. 5G). A flexing apparatus is added to the machine to work in conjunction with the 2 mm perforated screen (FIG. 5H). The existing drive section 14 and enclosure sections 15 remain the same except for the addition of a drive shaft and gearbox that is used to power the flexing apparatus module.
Various screen sizes and configurations can be exchanged in the screen section without affecting the other modules. The enclosure section can be modified or exchanged to accommodate larger debris as required without affecting the other sections of the machine. The drive section can be modified to accommodate higher speeds or lifting capacity without affecting the other modules, and other modules can be added to the machine for other capabilities such as the flexing apparatus modules as shown in the FIG. 5H.
It is also contemplated within the scope of this invention to completely enclose the flex rake of this invention with all of its component parts. Such an enclosure is illustrated in FIGS. 5E and 5F.
The novel effector module 16 of this invention is illustrated in FIG. 5I and consists of a frame 17 consisting of two sides 18 and 18′ and a common axle 19 between them which is located near the top 20 of the effector module 16.
There is also shown a second common axle 21 which is located between the sides 18 and 18′. Shown at one end of the axle is a drive mechanism that in this particular case, is commonly driven by a motor 22 shown in FIG. 5H and a drive mechanism 23 consisting of normal accompanying gears and the like. The second common axle 21 is driven by the drive mechanism 23 and drives sprockets (not shown) that have flex linked chains 24 on each end of the second common axle 25 that has attached to it a series of effector plates 25, which effector plates 25 are configured to align with the perforated screen 6 (best shown in FIG. 5H). The effector plates 25 are perforated 26 such that water can flow from them.
The effector plates 25 are equipped to receive water from a delivery system illustrated generally as 27, and are synchronized to allow the flow of water when they are aligned with the perforated plate 6. Only one series of effector plates is shown for clarity, it being understood that there are multiple cross members 25 and multiple series of effector plates 25 in the apparatus.
The removal of debris from a statically positioned perforated screen for the purpose of water filtration requires a very distinct series of dynamics to effectively remove the debris without applying destructive forces to the perforated screen element.
The application of a statically positioned screen inherently requires the debris to be removed from the screen area that is at the effect of the hydrostatic and flow forces of the incoming dirty water. The first dynamic necessity is to reduce or remove the hydrostatic pressure holding the debris against the screen over an area large enough to dislodge the debris relative to the size of the debris.
In the case of the application of a statically positioned perforated screen in municipal waste water, this debris can range from essentially 0.0001 m²to 0.1 m². Failure to reduce or remove the hydrostatic force holding the debris to the screen element will result in the failure to effectively remove the debris unless scraping forces that exceed the hydrostatic forces are applied to the moving of the debris along the screen surface, which in prior art devices, damage occurs to the screen element.
To reduce or remove this hydrostatic force in the case of the perforated plate screen, a device called an Effectors® (Duperon Innovations, Saginaw, Mich. USA) is positioned very near to or intimate to the downstream side of the perforated screen. This device reduces or removes the hydrostatic on the debris by transferring these forces to the surface of the device near or intimate to the screen. In addition to this transfer of force, a diverted flow pattern is created about the device.
This diverted flow pattern has a distinct effect on any debris that is dislodged. This effect can and will move debris along the surface of the screen by utilizing the higher velocity flows diverting around the surface of the Effector device that is near or intimate to the screen. In addition and related to this diverted flow pattern, a low force pocket is formed on the upstream side of the screen in front of the Effector, relative to the size of the Effector and the velocity of the incoming water stream.
This low force pocket forms a space for the debris to gather after it has been remove from the screen. In addition to the function of the Effector, there is a sprayer integrated into Effector, spraying from the downstream through the screen to the upstream side of the screen. The purpose of the sprayer is to positively dislodge the debris from the screen that has stapled (reached through) the perforations of the screen. The sprayer is positioned relative to the low force pocket.
To collect the dislodged debris and transfer it to discharge point, a skimmer device positioned on the upstream side of the screen moves relative to the position of the Effector. The position of the skimmer device, relative to the Effector, is critical to the distinct formation of the low force pocket and the direction of the diverted flow pattern in front of the Effector.
Each of these dynamics are interdependent. The reduction or exclusion of any of these dynamics greatly reduces or negates the ability to remove the debris from the statically positioned perforated screen in the design of the perforated plate. For example, by eliminating the low force pocket in front of the Effector, the sprayer, in and of itself, is unable to neatly remove the range of debris from the screen so the skimmer device can collect the debris for transport. This is due to the effective spray force required for debris with a large area which differs greatly from that required for small debris, in an uncontrolled environment. The combined effects of the low force pocket and the diverted flow patterns, equilibrate the spray forces required to neatly dislodge the debris from the screen and allows the skimmer device to collect the debris.
In addition to the primary debris removal device used in the clearing of debris from a perforated plate filtration screen, such as a skimmer, scraper or sprayer, a novel secondary skimming device 28 follows after the primary, attached to, or near to the primary device (trash screen), or in a position preceding the introduction of more debris to the perforated screen. Preferred mounting is to have the secondary skimmer mounted on the bottom of the primary skimmer, and extending forward past the leading edge of the primary skimmer, (See FIGS. 7 and 8), using a mounting plate 29 as shown in FIG. 9.
The purpose of this device is to clear fibrous material from the screen that has reached through the perforated screen and is unaffected by typical primary removal devices. This failure of fibrous debris remaining on the screen is called “stapling”.
The device is a thin and flexible sheet that is formed, or fixed to its attachment point, in a manner to allow consistent force along its edge, to the surface of the perforated screen. The material hardness of the sheet is designed to be sacrificial to the perforated screen and the thickness of the sheet is designed to maintain a consistent effective sharpness along its edge regardless of wear along the edge of the sheet.
The ability of the device to remove singular fiber or masses containing multiple fibers lies in the combination of the low consistent force and consistent effective sharpness. As the device moves along the inlet side surface of a perforated screen, the sharp edge gathers the fibrous material and moves it along the surface of the perforated screen to a point where it can be discharged.
This device is affixed to the bottom surface of the primary skimmers such that it touches the perforated screen, and hence, the fibrous material positioned in the perforations of the perforated screen. (See FIG. 4A.

Claims

What is claimed is:

1. A flexing apparatus for a rake screen, said flexing apparatus

a. an attached support arm attached at each attachment points each said support arm having a distal end;

b. attached to each said support arm distal end, a means for enhancing the movement of a chain;

c. said bottom end and top end of said elongated rail having a first roller incorporated therein;

d. there being secondary pivotally mounted second rollers in each said elongated rail, near each said top end second rollers.

2. The flexing apparatus as claimed in claim 1 wherein said means for enhancing the movement of a chain in d. is pivotal.

3. The flexing apparatus as claimed in claim 1 wherein said means for enhancing the movement of a chain in d. is a roller.

4. The flexing apparatus as claimed in claim 1 wherein said means for enhancing the movement of a chain in d. is a slide rail.

5. A rake screen apparatus having a flexing apparatus of claim 1 mounted to a framework of said rake screen apparatus.

6. A dual wiper blade assembly for a rake system, said dual wiper blade assembly comprising:

a. a pair of support members each having a near end and a distal end, each said near end having pivotal attachment capability for attaching to a framework of a rake system;

b. each said distal end of said support member having attached thereto, holders, each said holder having a bottom edge;

c. each said bottom edge having a first notch therein and a spaced-apart second notch therein;

d. a common first wiper blade attached in said first notches and a common second wiper blade surmounting said first wiper blade and attached in said second notches.

7. A rake screen apparatus having a dual wiper blade assembly as claimed in claim 5 mounted to a framework of said rake screen apparatus.

8. A stand-alone modular unit comprising a bar screen, said modular unit configured to replace a bar screen in an existing rake screen apparatus.

9. A stand-alone modular unit comprising a perforated plate assembly, said modular unit configured to replace a perforated plate assembly or bar screen in an existing rake screen apparatus.

10. A pivoting drive head apparatus for a rake screen, said pivoting drive head comprising:

a. a pair of space-apart, parallel support members, each said parallel spaced-apart member having a near end, a distal end and a middle portion;

b. each said near end being pivotally attachable to a framework of a rake screen;

c. each said parallel support member being pivotally attached to a drive sprocket, each drive sprocket being mounted on the ends of a common drive shaft therebetween, each said drive sprocket being attaché to each respective parallel support members near said middle portion of said parallel support member;

d. each said distal end of said parallel support member being configure as a stop foot;

e. each said parallel support member, each said sprocket and said common drive shaft being pivotable away from said rake screen framework.

11. A rake screen apparatus having a pivoting drive head apparatus as claimed in claim 9 mounted to a framework of said rake screen apparatus.

12. A rake screen apparatus as claimed in claim 12, wherein, in addition, there is present a flexing apparatus.

13. A rake screen apparatus having a fixed drive head and a flexing apparatus as claimed in claim 1.

14. A pivoting closure cap for a rake screen apparatus having side framework, said pivoting closure cap comprising:

a. a top panel;

b. two mirror image side panels having edges and, top front corners, being attached at said edges to said top panel;

c. a back panel having edges and attached at said edges to said top panel and said side panels;

d. each said side panel being configured to accommodate any components extending beyond said side panels such that said components will not interfere with closure of said pivoting closure cap;

e. a flexing enclosure lid, pivotably mounted at said top front corners of said side panels.

15. A rake screen apparatus having a pivoting closing cap as claimed in claim 15 mounted to a framework of said rake screen apparatus.

16. A rake screen apparatus containing in addition, in combination a flexing apparatus as claimed in claim 1, a dual wiper blade assembly as claimed in claim 5, a pivoting drive head apparatus as claimed in claim 9, and a pivoting closure cap as claimed in claim 11.

17. A rake screen apparatus in which screens, drive mechanisms and enclosures are all modular, wherein each said screens, drive mechanisms and enclosures can be removed or replaced without disassembling said entire rake screen apparatus.

18. A modular component for a rake screen that is a screen module.

19. A modular component for a rake screen that is a drive module containing a drive and a skimmer system.

20. A modular component for a rake screen that is an enclosure module that has the ability to be modified to create clearance for various size debris moving through said rake screen.

21. A modular component for a rake screen that is a flexing apparatus as claimed in claim 1.

22. An rotary effector module for use with a trash rake, said effector module comprising:

a. a frame, said frame having a top end, and bottom end, and two sides;

b. a first common axle extending between the said two sides near said top end;

c. a second common axle extending between said the two sides and located beneath the first common axle,

d. said first common axle and said second common axle driveably connected by a common drive assembly;

e. said second common axle having a sprocket located at each end, each said sprocket having a drive chain located thereon, each said chain having a lower end;

f. each said chain not being mounted on a sprocket at said lower end;

g. there being a plurality of cross members equally spaced between said chains;

h. each said cross member having mounted thereon skimmers, each said skimmer interfacing with a backside of a perforated plate filtration screen of a trash rack, each said shimmer having a leading edge.

23. A flex rake having primary skimmers, in which at the bottom leading edge of each said primary skimmer, there is a thin, flexible sheet attached in a manner sufficient to apply a low, consistent force along a leading edge of the thin, flexible sheet, against a surface of a perforated screen in said flex rake.