Brief description of the Drawings - Ipindiaservices.gov.in

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Feb 22, 2014 (2 years and 9 months ago)

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FORM 2

THE PATENTS ACT, 1970
(39
of 1970)

&

THE PATENS RULES, 2003

COMPLETE SPECIFICATION

[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.

1


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.
Backgrou
nd
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 th
e 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

2

rake system raises a scrapper along heavy rake and requires heavy electr
ic
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 carr
ied 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 solid
s. Further,
this patent uses two cables, two winch drums and is complicated.


Summary of the present invention:

3

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 connect
ed pivotally to the free end of the lower

member.

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 bo
ttom 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

tank.

According to the another embodiment of the preset invention, a rotary bridge

of the settling ta
nk comprises at least one scrapper
-
raising system of the

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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 pre
sent invention is a single or multi
compartment
settling tank comprising a bridge having a scrapper
-
raising system of the
present invention.

The abo
ve 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 comprisi
ng 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 thereo
f 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 disc
harge 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

5

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 c
entral 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
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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
pur
pose. The
percentage of the suspended solid in the water to be purified is

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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 rectangul
ar 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 suspensio
n
(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 de
veloped 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 a
ttached 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

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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 t
wo 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 p
ulleys (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 orthogo
nal 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 sett
ling 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

8

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 th
e 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 purificati
on
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 c
hanges 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.

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