|Title of Invention
SCRAPER RAISING SYSTEM
|The present invention relates to the scrapper raising system of settling tanks. The scrapper - raising system for a settling tank comprising a vertical suspension having an upper member and lower member wherein said upper member is rigidly fixed to a rotating bridge of the settling tank and said lower member is pivotally adapted to the upper member, a scrapper connected to the lower member, and a lifting means attached at or near the lower end of the lower member for raising and lowering the scrapper wherein said lifting means raises the scrapper in a direction substantially orthogonal to thrust developed by the scrapping force of the scrapper. Reference Fig.2
| FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
THE PATENS RULES, 2003
[See section 10, Rule 13]
SCRAPER RAISING SYSTEM
DANAVADE VIDYADHAR BANDU, AN INDIAN NATIONAL OF 705, 'A', SHIVAJINAGAR (SOUTH), SANGLI-416416, MAHARASTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
Field of the Invention:
The present invention relates to settling tanks for example clarifiers, sedimentation tanks, particularly to scrapers of the settling tank and more particularly to raising system for the scrappers of the settling tank. Background And Prior Art of the Invention
Generally, settling or sedimentation tanks are used for water treatment or sludge treatment. The conventional settling tank comprises a circular or square settling tank having conical bottom and a rotating scrapper system. A rotating scrapper system comprises a rotating bridge made of structural steel supported on the central shaft and top surface of the outer wall of the tank and scrappers are connected fixedly to the rotating bridge via vertical suspensions. The scrappers engage and move sediment and sludge collected at the bottom of the tank to a central discharge sump. Generally, the rotating bridge completes 3 to 4 revolution per day to rake the settled solids.
The main problem observed in the settling tank is that the scrapper system may get jammed and/or corroded due to sludge depositions when the scraper system is not in operation or driving means of the rotating bridge are under maintenance. To encounter the said problem US 4,462,908 suggests a rake lifting means for sedimentation apparatus which discloses a motorized lifting mechanism for the rake arms of a sedimentation tank which comprises spaced vertical pairs of pivot link arms interconnecting the rake arm frame to a main center rake arm drive cage and wherein the rake arm frame is in turn interconnected to a motorized jack lifting screw by means of a cable to raise the arm upon the pivoting of the pivot arms. However, said
rake system raises a scrapper along heavy rake and requires heavy electric motor.
Further, a GB 2361196 patent discloses a mechanism provided for lifting scraper arms in situ relative to the supporting bridge of a rotary or other sludge scraper assembly of a settling tank or the like. According to this patent the arms are carried by a frame, which is slidable up and down a vertical stainless steel tube by means of a winch, cable and pulleys. However, the frame of the arms of the said patent is under water which may get jammed due to the deposition of the sludge inside the frame and the tube over which said frame slides for lifting the arm. Further more A GB520.935 patent discloses an improvements in and relating to sedimentation apparatus wherein a scraper or suction device for collecting sludge on the bottom of a settling-tank is supported by an arm or the like hinged to traveling-means and comprising hinged elements which are moved into a folded position to raise the scraper or suction device. A scraper is carried by a pair of arms hinged to a carriage traveling on rails, each arm comprising two hinged members, the lower ends of which are raised by at least two cables, passing round two winch drums of different diameters on a common shaft. The parts may be so proportioned that the scraper moves vertically as it is lifted to its inoperative position above the tank. However, resultant of opposite thrust developed due to the scrapping of the scrapper may result in raising or folding of the scrapper during scrapping process leading into the insufficient scrapping of the settled solids. Further, this patent uses two cables, two winch drums and is complicated.
Summary of the present invention:
It is an object of the present invention to provide a scrapper raising system
that raises scrappers and obviate above-mentioned problems.
In a preferred embodiment, the present invention provides a scrapper-raising
system for a settling tank comprising a vertical suspension having an upper
member and lower member wherein said upper member is rigidly fixed to a
rotating bridge of the settling tank and said lower member is pivotally
adapted to the upper member, a scrapper connected to the lower member,
and a lifting means attached at or near the lower end of the lower member
for raising and lowering the scrapper wherein said lifting means raises the
scrapper in a direction substantially orthogonal to thrust developed by the
scrapping force of the scrapper and the said forces are in different planes.
The scrapper can be connected pivotally to the free end of the lower
In one of the preferred embodiment of the present system, a holding means
may adapted between the free end of scrapper and the upper member of the
vertical suspension to hold the scrapper parallel to the bottom of the tank
while lowering and raising the scrapper.
According to the present invention, the position of the pivot between the
upper member and lower member of the vertical suspension depends upon
the parts per million (ppm) of the suspended solid particles in the liquid and
number of the settling tanks and/or number of the partition in the settling
According to the another embodiment of the preset invention, a rotary bridge
of the settling tank comprises at least one scrapper-raising system of the
present invention wherein the cable for raising and lowering the scrapper are connected to a common drum or winch by passing over guide pulleys. Further embodiment of the present invention is a single or multicompartment settling tank comprising a bridge having a scrapper-raising system of the present invention.
The above and other objects and advantages of the present invention will appear more fully hereinafter from a consideration of the detailed description which follows taken together with the accompanying drawings wherein one embodiment of the present invention is illustrated.
Brief description of the Drawings
Fig 1 shows a setting/sedimentation tank:
Fig 1A is a top view of the settling tank;
Fig 1B is a cross section of the front view of the settling tank.
Fig 2 shows a cross section view of the bridge comprising a scrapper raising system according to the present invention.
Detailed Description of the Invention:
Referring now to the drawings for a more detailed description of the present invention a sedimentation settling tank incorporating an embodiment thereof is generally indicated by reference numeral (10) in Fig 1. Generally, settling tank (10) includes a conical shaped bottom (12) and a peripheral wall (14) provided with annular flow launder (13). A center column (16) is surrounded by an annular sump discharge zone (15) from which collected sludge/settled solids are withdrawn or pumped to discharge conduit (18). A square frame cage (19) supports a rotary bridge (20) atop center column (16), which is driven within the periphery of the settling tank (10) by gear mechanisms in a
well-known manner about the vertical axis of column (16). Fig 1 shows a settling tank (10) for water purification, which generally comprises flocculation zone (A) at the center and annular clarifier zone (B) with a central water inlet (22). Water to be purified is introduced at the center of the tank via central water inlet (22) in flocculation zone (A) and suspension-free water is pumped from the annular flow launder (13). The rotary bridge (20) generally completes 3 to 4 revolution per day to scrap solids settled on the conical bottom (12) of the settling tank (10) in the sump (15) by means of the scrapper (30) adapted on the vertical suspension (25) of the rotary bridge (20).
According to the present invention, the vertical suspension (25) is divided in two members, upper member (26) and lower member (27). The upper member (26) is rigidly fixed to the rotary bridge (20) directly or to a carriage on the rotary bridge (20) by any convenient means for example welding, screwing. The lower member (27) of the vertical suspension (25) is pivoted to the upper member (26) by hinges or the like (28) and allowed to pivot in raising direction only shown as 'X' in Fig 2 i.e. the lower member is allowed to pivot between bottom rest position of the scrapper (30) and scrapper raised position shown in dotted lines in Fig 2.
The position of the pivot between the upper member (26) and lower member (27) mainly depends upon the Parts per million (ppm) of the suspended solids in liquid or water and number of compartments of the settling tanks and/or type of the settling tank. For example, the settling tank as shown in the Fig 1 is useful for the purification of water, which is used for the drinking purpose. The percentage of the suspended solid in the water to be purified is
less and therefore, the pivot between the upper member and lower member is shown below the water level in Fig 2. Alternatively, the pivot between the upper member and lower member of the vertical suspension can be provided above the water/liquid level where high maintenance or removal of the scrapper blade requires repeatedly, or the pivot may be provided above the peripheral wall of the settling tanks of rectangular shape. According to the present invention, the scrapper (30) is pivotally connected to the lower member (27) of the vertical suspension (25) by means of hinge or the like (29) and free end (31) of the scrapper (30) is connected to the vertical suspension (25) to hold the scrapper (30) parallel to the bottom (12) of the settling tank (10) while lowering and raising the scrapper (30) via a holding means (32) such as cable. The holding means (32) further allows uniform distribution of the opposite thrust developed due the scrapping among the scrapings system. The scrapper raising system mounted on the bridge in such a way that angle made by the scrapper to the diagonal of the tank is similar to that of the scrapper of the conventional settling tank required for scrapping solids settled on the bottom of the tank. Alternatively, the scrapper (30) can be fixedly connected to the lower member (26) at a substantially angle required to rest on the bottom of the settling tank. A lifting means (40) such as cable is attached at or near the lower end (27A) of the lower member (27) and is attached to winch drum (42) mounted on the rotary bridge (20) of the settling tank (10) by passing over pulleys (44). The winch drums of each scrapper raising system may be adapted on a common shaft (not shown) adapted on the rotary bridge (20), which can be driven
manually or electric motor to raise or lower the scrappers. Alternatively, hydraulic system or the like can be adapted to raise the scrappers. Fig 2 shows two scrapper systems according to the present invention connected pivotally to the upper member (26) of the vertical suspension (25) below the water level (17) and cables (40) of the scrapper raising systems are connected to a common shaft (not shown) via pulleys (44). The common shaft on rotation raised the scrapper in opposite direction. The lower members (27) of both raising systems act as stoppers to each other and restrict pivotal movement in the opposite direction of the raising direction of the lower member (27).
In the operation of the apparatus, by operating winch drums mounted on the common shaft by manually or electric motor, the scrappers are lowered to engage with the tank bottom or surface of the bed of the settled solids formed on the bottom of the tank. The rotary bridge is then propelled to rotate about the vertical axis of the settling tank to scrape the solids settled on the bottom of the settling tank in the sump. As the lifting means raises the scrapper in a direction substantially orthogonal to thrust developed by the scrapping force of the scrapper and in different plane, the scrappers do not fold due to the scrapping force and results in the effective scrapping. After completion of rotations, the rotary bridge is stopped or when the settling tank is not in use or under maintenance or when scrappers are required to shift into another compartment or to adjust the position of the scrapper on the bridge, the scrappers can be raised as soon as the rotation of the bridge is stopped by rotating the winch of each raising system through the common shaft. Raising and lowering operations of the scrappers can be operated
automatically by allowing the electric motor of the common shaft to trigger on/off as soon as the rotation of the bridge stops or starts. When the rotary bridge is allowed to rotate after a long period, a thick bed of the settled solids form on the bottom of the settling tank. The holding means of the scrapper and the pivot of the scrapper with the lower member of the scrapper raising system of the present invention allow the scrapper to rest on the bed of the settled solids and also scraps the solids in the sump of the settling tank.
The scrapper raising/lifting system according to the present system can be used for rectangular sedimentation tanks as well as for circular settling tanks such as sewage treatment plants, sludge removal plants, water purification tanks or the like where solids settled on the bottom surface are required to scrap into the discharge zone. Further, the scrapper raising/lifting system of the present invention is very simple and cost effective as it can be operated manually. The said scrapper raising system can be used for single as well as multi compartment settling tanks.
Although one embodiment of the present invention has been described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of parts without departing from the spirit and scope thereof as the same will now be understood by those skilled in the art.
|Indian Patent Application Number
|PG Journal Number
|Date of Filing
|Name of Patentee
|DANAWADE VIDYADHAR BANDU
|705,'A',SHIVAJI NAGAR (SOUTH), SANGLI, MUMBAI-416416.
|PCT International Classification Number
|PCT International Application Number
|PCT International Filing date