Waste material pond cleaning apparatus

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Patent issued

05/09/1995

Inventor(s):	Staples, Wesley A. Staples, Russell E.
Application	No. 08/130,985 filed on 10/04/1993
Current US Class	37/342, 37/314
Field of search	172/779, 172/787, 172/799.5, 172/684.5, 172/786, 172/26.5, 37/214, 37/341, 37/309, 37/314, 37/342
International Classes:	E02F 300
Examiners
Primary	Reese Randolph A.
Secondary	Batson Victor
Attorney, agent or firm:	Stowell; Harold L. Kerkam, Stowell, Kondracki & Clarke
US patent references	231581, 273998, 311746, 526675, 754611, 963562, 1034501, 1096137, 1192127, 1303415, 1437358, 2812596, 2864182, 3276152, 4056328
Foreign patents	23214 (11/30/1999, GB), 1728911 (03/31/1992, SU)

A dragline apparatus for cleaning waste material and sludge in clarifierand settling ponds and lagoons includes a pair of side walls and a backwall forming a frame supported on front and rear flotation rollers.Between the home member is at least one blade, pivotally mounted forswinging movement from an active to an inactive position. Cables areconnected to the front and rear of the frame and to prime movers on thebanks of a pond to be cleaned.
FIELD OF THE INVENTION
This invention relates to an apparatus for cleaning waste material sludgeand soft solids in clarifier settling ponds and lagoons. The inventionwill be further described in respect to the recovery of soft solids inpools which may be five to twenty-plus feet deep and two hundred to eighthundred feet wide, and any length, and enclose as much as eighty or moreacres.
BACKGROUND OF THE INVENTION
All categories of waste have created gigantic service industries directedto clean-up and disposal of wastes. One of the large waste problems hasbeen created by the pulp and paper industry, where waste materials havebeen stored in "sludge," "polishing," "processing," and the like ponds.Such ponds are normally located in the waste system from the millclarifiers. As the waste gathers in the mill's waste system, the wastesare pumped into clarifier(s) for the start of the separation of solidsfrom liquids.
In the pulp and paper industry, much of the solids material is paper wastebecoming fiber in the waste system and accounts for 90%-plus of the wastedsolids. As the clarifier separates the solids, they are pumped out of thebottom of the clarifier as they sink and are pumped into these "ponds" forbreakdown by microorganisms. Generally, the solids are left in the pondand, through "weir gates," the liquid is returned to the clarifier forfurther clarifying and, eventually, to an oxidation pond for additionalclarification and eventual return to public waterways.
The solid materials left in the pond to further decay and be completelybroken down to inert material and dead "bugs" are the subject of ourfurther discussion here. This material is left to accumulate for a numberof years and, in time, it fills the total capacity of the pond to a pointthat the pond is no longer functional and becomes inefficient, sendingmore and more solids back into the clarifier. These ponds, full of thesesoft-solids and water, and each covering 80 acres or more, may be 5 to 20feet deep, and 200 to 800 feet in width. The removal of this soft-solidmaterial from the lagoon and into a retention or land-fill area becomes areal challenge to man and machine.
The state-of-the-art approach for cleaning ponds seems to be as follows:
A. Divert the material "slurry" flow into an alternate pond or divide thepond with a dirt dike, which will later be removed, and divert the flowinto one side of the pond. Pump all liquid into the same pond to which theflow of material is being diverted.
B. Reach as far out as possible with a dragline or long-reach excavator toremove all reachable materials from the bank of the pond.
C. Place a light-weight, low ground pressure (LGP) bulldozer into the pitof the pond to push the remaining solids to the bank so that it can beloaded out by conventional means.
Item C. above has many drawbacks; with the soft bottom of the pond and theooze factor of the sludge, the bulldozer units are bogged down in thebottom much of the time, and these small tractors can push only smallpayloads, resulting in very low production.
The present invention is not limited to ponds containing soft pulp andliquids and may be useful, as disclosed in U.S. Pat. No. 4,753,737. In thepulp and paper industry, a very caustic solution called white liquor isused in the digesters for cooking wood chips for the production of pulp.This combination (wood chips and white liquor) is sealed in a cooker, andsteam is introduced, and it "cooks" under high pressure. After cooking,this mixture is "blown" from the digester and goes through a separationprocess. This process separates the pulp from the liquid, which isreferred to as black liquor. The black liquor contains severalbyproducts--turpentine and "soap" (from which tall oil is made) aretwo--plus residual chemicals and B.T.U. (heat) values. After theby-products are removed, the black liquor contains chemical and B.T.U.solids in the magnitude of about 10%. The higher the solids, the greaterthe value of the black liquor. In order to recover the values, the blackliquor is processed through evaporators in which the water is removed,and, in several stages, the solids content is raised to 55%-62% forburning in recovery boilers. In the burning process in the recoveryboiler, the heat value is removed for the production of energy, and thechemical elements form a smelt matter called green liquor. This greenliquor drops into a heat sink-pool at the bottom of the boiler and isremoved for processing through a lime kiln for the production of whiteliquor. Quite frequently, prior to recovery of the values in the blackliquor, the black liquor is stored in ponds, pools and lagoons.
These large lagoons contain vast amounts of liquor, ranging in solidscontent from weak 2%-20% to heavy 25%50%. They may remain in such a lagoonfor months (in some cases, actually years) before limited recoverycapacity can reclaim them back into the system. As the black liquorsettles, the solids drop to the bottom of the pond as they fall out ofsolution and suspension. Also, the heavier the solids, the faster theyfall. This is especially true as the high processing temperatures fall inthe lagoon environment. The black liquor solids form heavy, thick layersover time and become quite firm. The present invention comprises anapparatus for recovery of the black liquor solids from storage ponds.
SUMMARY OF THE INVENTION
The invention can be generally defined as including a side-and-rear-walledframe, basically open at the front, top and bottom; support float rollersand/or wheels supporting the frame at its front and back with the support,when they are rollers, extending at least substantially the width of theframe, and at least one blade pivotally mounted for swinging movement froman active digging position to an inactive position; cables attached to thefront and rear of the frame and to prime movers on the banks of the pond;and a further cable connected to a lever arm mounted to the at least oneblade for moving the blade between its active and inactive position.
In a preferred form, there are two blades, and each blade is pivotallymounted for swinging movement from an active to an inactive position, andthe two blades are connected by cable means for movement in unison.

It is claimed:
1. Apparatus for cleaning waste material and sludge in clarifier andsettling ponds, comprising a pair of side walls and a rear wall defining aframe open at the top, front and bottom, rotatable support meanssupporting the frame at the front and back of the frame, at least oneblade pivotally mounted for swinging movement from an active to aninactive position between said side walls of the frame and cables attachedto the front and rear of the frame, a lever arm connected to the at leastone blade, and further cable means connected at one end to the lever armand connected at the other end to the cables attached to the front andrear of the frame for moving the at least one blade to its active andinactive position, wherein the support means comprise floatation rollerssupporting the frame at the front and the back of the frame, said supportfloatation rollers extending at least substantially the width of the frameand enabling said apparatus to float substantially on top of the wastematerial and sludge.
2. The apparatus, as defined in claim 1, further including a second blade,means pivotally mounting the second blade for swinging movement from anactive to an inactive position and cable means connecting the said bladeand said second blade for simultaneous movement.
3. The apparatus, as defined in claim 1, wherein the support rollers eachhas a cylindrical outer surface and a plurality of spaced drag stripssecured to the cylindrical outer surface of each roller.
4. The apparatus, as defined in claim 2, wherein the said second blade ispositioned rearward on the frame of said one blade, and said second bladeis positioned lower than said one blade.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a dragline, dual-blade scraper havingsupport rollers at the front and rear thereof;
FIG. 2 is a sectional view through one form of the present invention havingtwo blades and being towed across a pond with the blades in the activepositions;
FIG. 3 is a view like FIG. 2, with the dragline scraper being pulled in therearward direction and with the blades in an inactive position;
FIG. 4 is a view like FIG. 2 of a modified form of the invention whereinthe rearward blade is larger than the forward blade and penetrates intothe material to be mucked to a greater distance;
FIG. 5 is a view like FIG. 2 of a further modified form of the inventionwherein the front and rear rollers are replaced by conventional wheelshaving rubber tires; and
FIG. 6 is a somewhat diagrammatic view of a pond and a pair of prime moversfor dragging to and from across the pond.
DESCRIPTION OF THE INVENTION
Referring to the drawings, 10 generally designates a unique draglinescraper. The scraper includes side walls 12 and 14 and back wall 16. Theside and back walls are attached to side beams. The side frames 18 and 20have secured thereto front and rear bearing blocks 21 and 22, into whichare journaled stub shafts 24 and 26, which stub shafts are secured tofront and rear floatation rollers 28 and 30. The floatation rollers havelaterally extending cleats 32 secured thereto which assist in causing therollers to rotate when the scraper is dragged in the forward or rearwarddirections. At the forward end, a harness, generally designated 34, isconnected to the side frame members 18 and 20, and thence to a dragline36. A similar harness 38 is secured at the rearward end of the scraper andto a rearward-pulling dragline 40.
Also secured to the connector 42 at the forward end of the vehicle is cable44, to be described in greater detail hereinafter. A single cable at therearward end, designated 48, is attached to connector 50, again to bedescribed in greater detail hereinafter.
Between the side walls or frames 12 and 14 are mounted a pair of scraperblades 52, adjacent the forward end of the vehicle, and 54, adjacent therearward end of the vehicle. The scraper blades are attached to shafts 56for the forward blade and 58 for the rearward blade. Also secured to shaft56 is a lever arm 60 and, at the rear, a lever arm 62 is connected toblade 54. Motion of the lever arms 60 and 62 moves the blades. When thecable 44 is urged in the forward direction, the blades are moved to theactive or digging position, and the blades are moved in the oppositedirection when cable 48 is urged rearwardly as the vehicle is towed in arearward direction. A frame, generally designated 66, is secured above theblades 52 and 54, and a cable 68 is centrally attached as at 70 to theframework 66. It is through this cable 68 which, at the appropriate time,lifts the scraper vertically upward to release the mucked materialcollected between the side walls and the back wall 12, 14, and 16.
In order to reduce the strain or torque on cable 44 during forward anddigging movement of the scraper, each of the blades has a stop member 69,which stop members are secured to the side beams 18 and 20.
Referring particularly to FIG. 6, there is shown a portion of a pond 72,and on opposite banks are two prime movers in the form of cranes,designated 74 and 76. The crane 76 has a reel, not shown, for cable 36 todraw the scraper in the direction of the directional arrow, and the mainreel of the crane has attached thereto, at the top of the boom 78, thecable 68, which attaches to the frame 66 for lifting the vehicle free ofthe collected solids when the unit reaches the bank 80. The crane 74 has acable reel, not shown, to which is attached the cable 40 for dragging theunit 10 to the bank 82 after the mucked material has been deposited onbank 80. In the reverse direction of movement of the vehicle 10 to thebank 82, substantially no pond debris or sediment is collected, as themotion of the vehicle is opposite to the digging slope of the blades.
Referring to FIG. 4, the vehicle 10' comprises a modification from vehicle10, in that the blade 54' is greater in length than blade 52. In this formof the invention, with a longer blade 54' in the rear, a greater load ofmaterial is collected by the pair of blades. It is also contemplated thatonly a single blade, either 52, 54, or 54', can be carried by the beamsforming the frame of the mucking machine.
In operation of the dragline scraper, the float-type cylindrical barrels 28and 30 keep the machine from sinking too deeply in the soft material beingremoved from the pond, eliminating the difficulty in mucking ponds withso-called lightweight bulldozers which have a tendency to sink too deeplyinto soft material, rendering the normal operation of the lightweightbulldozer impractical.
Referring now to FIG. 5, there is shown a modified form of the presentinvention, wherein the floatation rollers 28 at the front and 30 at therear are replaced with a pair of rubber-tired wheels 28' at the forwardend and a similar pair at the rear, designated 30'. The importance of thismodification is to prevent the steel rollers 28 and 30 from mashing the"soft material" out of the path of the blades as the unit nears the hardbottom of the pond being excavated. Generally, as the level of the sludgeis reduced to, for example, 18 inches or less, the rubber-tired wheels areused to insure that the unit will load properly and cleanly. The rearblade is also raised to the same level as the front. This preventsleveling streaks of sludge where the bottom has almost already beencleaned.