FIELD OF THE INVENTION
The present invention relates to a lifting system, which has an improved load
stability and higher safety during transportation of long cylindrical storage
vessels. More particularly, the invention relates to a system for lifting and
supporting of a long slender structure in particular Feed Water Storage Tank of
Deaeration system adopted in thermal power plant.
BACKGROUND OF THE INVENTION
A Deaeration system is used mostly in Thermal Power Plants, industries like
Petroleum, Refinery, Paper industry etc., where it removes oxygen and other
dissolved gases from the feed water to steam-generating boilers. The complete
assembly of a Deaeration system basically comprises :
1. A Deaerator (Upper Tank)
2. A Feed Water Storage Tank (Lower Tank)
The Storage Tank per se constitutes a long slender structure. Accordingly, Lifting
and transportation of the structure involves risk of damage. Thus, the storage
tank is currently fabricated into sub-assemblies which are transported, welded
and erected at site. The major drawbacks of the prior art are: increase in
erection time, production time, transportation and erection cost. Moreover, the
assembly requires a stringent welding accuracy to avoid welding defects on
storage tank. Accordingly, there is a need to propose a suitable device which is
enabled to lift an assembled Storage tank and provide structural support to the
tank during transportation.

OBJECTS OF THE INVENTION
It is therefore an object of present invention to propose a system for lifting and
supporting of a long slender structure in particular Feed Water Storage Tank of
Deaeration system adopted in thermal power plant.
Another object of the invention is to propose a system for lifting and supporting
of a long slender structure in particular Feed Water Storage Tank of Deaeration
system adopted in thermal power plant, which has improved load stability and
ensures safety during lifting of seamless cylindrical structure.
A still another object of the invention is to propose a system for lifting and
supporting of a long slender structure in particular Feed Water Storage Tank of
Deaeration system adopted in thermal power plant, which prevents excessive
deflection of a storage tank and limit the stresses up to acceptable safe limits.
A further object of present invention to propose a system for lifting and
supporting of a long slender structure in particular Feed Water Storage Tank of
Deaeration system adopted in thermal power plant, which is capable of keeping
the long seamless tank in horizontal position and prevent horizontal sway of the
storage tank caused by differential movements of hooks of the operating cranes.

SUMMARY OF THE INVENTION
Accordingly, there is provided a system for lifting and supporting of a long
slender structure in particular Feed Water Storage Tank of Deaeration system
adopted in thermal power plant, comprising one each right side cage and left
side cage, each made up of a plurality of ISMB beams which are inter-connected
through a truss member assembly, at least three truss members oriented
perpendicularly with each-other are welded between the two cages in all four
corners of the cages, the truss members are laced with V - shaped bracings
which are welded by keeping constant distances amidst all the truss members in
full length, a middle frame consists of four ISMB beams which is welded to the
system body such that centre of gravity of the lifting structure coincides with the
centre of gravity of the lifting means; and at least two pairs of ropes attached at
each corner of both the cages through eye-hooks including also at the top it is
two spreader beams attached to both the sides of the cages at the top portion of
the system.
The system of the invention constitutes an assembly of beams of various section
sizes. The system has an advantages of improved load stability, adequate
stiffness and strength for lifting the ODC-structures for example long seamless
storage tank. The system also supports the storage tank throughout its length
for a safe transportation. The system reduces the risk of deflection of the storage
tank during lifting and transportation. From the manufacturing point of view, the
system elimates the requirement of manufacturing the tank in to sub-assemblies,
thereby reducing erection time and fabrication cost.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows a system of the invention accompanied with feed water Storage
Tank.
Figure 2 shows assembled isometric view of the system of the invention.
Figure 3 enlarged view of a right cage (2) of the inventive system showing its
subcomponents.
Figure 4 enlarged view of the truss structure (3) showing connection between its
subcomponents.
Figure 5 Saddle structure (B) being a part of the storage tank positioned on the
I-beam bottom members (7) of the inventive system through bolted joints.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
The system developed through this invention is capable of housing an entire
storage tank (A); shown in figure 1, providing additional stiffness along the tank
length to avoid deflection during lifting.
The system is basically a rectangular long frame assembly of I-beams and bars
of various sizes. The system comprises at least two cages (1,2) fabricated of I-
Beams of similar sizes; a plurality of inter-connected truss members (3),
connecting the corners of the cages (1,2). A middle frame (4) provided in

between the truss structure (3); and at least two pairs of steel ropes (5)
connected from each corners of the cages (1,2) through eye hooks, and attached
to one each spreader beams (6) at the top, i.e. each pair of steel ropes attached
to one spreader beam (6).
The spreader beams (6) (I beam) are provided to offer stability to the storage
tank during lifting by the crane hooks.
According to the invention, as the feed water storage tank is attached to bottom
support members (7) of the cage (1,2), through temporary (bolted) joints.
During lifting of the tank through the crane hooks from both the sides, the tank
shell positively transfers the load to the supporting members (7). Selections of
the supporting members (7), as well as the (11) truss members are optimized in
order to determine acceptable limits of deflection and stresses.
Selection of the supporting members (I-beams) and the truss members (11) are
always of an iterative nature. Initial configuration is selected corresponding to
the right and left cages (1,2). A rigorous finite element analysis is then carried
out to study the stresses and deflection pattern. The next step is an iteration of
the analysis wherein size and location of the support members (7) and the truss
members are accurately selected. Such analyses are repeated with the selected
members till an acceptable stress and deflection is arrived at.
A plurality of iterations performed during selection of optimized and economical
support members and the truss members, which is presented in a table-1 below.


According to the members selected as tabulated hereinabove, the summarized
results of the finite element analysis for deflection and stress of the system along
with the feed water storage tank. Consolidated results are tabulated in Table-II
which interalia shows that the stresses and deflection are maintained under the
allowable limit.


The inventive system as shown in figure 2, comprises :
a left side Cage (1);
a right side cage (2);
truss member assembly (3) connecting the two Cages (1,2);
a middle Frame (4);
at least two pairs of Steel rope (5), and
at least two Spreader Beam (6)
Sub-components of the left and right side cages (1) and (2) are as
follows-
I-beam bottom members of cage (7)
I-beam top member of cage (8)
I-beam vertical members of cage (9)
I-beam cross members of cage (10)
Sub-components of the Truss member assembly connecting the two
Cages (1,2) are as follows:
Interconnected Truss member (11); and
V-shape Bracings (12)

The present invention is illustrated along with the storage tank (A) in figure 1.
Figure 2 depicts the lifting system, which is an assembly of different beam
sections of different sizes. A detailed description of the system is given below.
The Right side cage (1), is substantially rectangular in cross-section, and
comprises several I-cross-section beams of similar section sizes in various
orientations. The bottom members (7) of the cage (1,2) are connected to top
members (8) of the cage (1,2) through vertical members (9) of the cage (1,2) at
four corner of the cage. In order to have more strength, at least two vertical
beams (9) at middle of the cage and four cross members (10) forming V-shape
are provided. The height and width of the system is decided by taking into
consideration the outer diameter of the storage tank (A) and the distance
between the two saddle supports (B) respectively. Figure 3 shows the connection
between the subcomponents of the cage. Likewise, the left side cage (2) is also
configured in the same manner in all respects as t hat of the right side cage (1).
The Truss member assembly comprises a plurality of circular cross section beams
which are varying in section sizes running amidst each of t he four corner of t he
left cage (1) and the right cage (2). In detail, three inter-connected truss
members (11) are facing each other perpendicularly (one is oriented towards top
side, other towards bottom side and middle one is connected between two
corners). These interconnected truss members (11) are laced with V-shape
bracings (12) of smaller size beams. These bracings (12) are welded maintaining
constant distances at top and bottom of the two inter-connected truss members
forming a V-shape (for reference see fig.3). Similarly, the procedure is repeated
for other three corners. These twelve truss members (11) provide additional
support and strength to the storage tank along with the device, is more stiffened
by further providing V-shaped bracings (12) as explained hereinabove.

The truss structure (3) connecting the two cages (1,2) minimizes the risk of
getting high deflection & high stresses at the middle portion and prevents
horizontal sway between the two cages.
The truss structure (3) is supported by the middle frame (4) and consists of at
least four I-beam placed at the middle of the system. Therefore, the centre of
gravity of the complete system and storage tank coincide with each-other.
Therefore, it has reduced the consequences of imbalancing the whole system
and housed storage tank in it.
The pairs of Steel rope (5) and the spreader beams (6) are provided to lift the
tank safely through the crane hooks from both the sides. In detail, the one pair
of steel roped is connected to the front two corners of the cage with an eye
chook and attached to one of the two spreader beams (6) at the top. Similarly,
the arrangement is repeated for back side and other end of the cage. This is
shown in figure 2. The long seamless cylindrical storage tank has five saddle
supports (B) which are positioned on the five bottom beams forming as a
platform. Referring to figure 5 showing partial view of the symmetrical platform
of I beams on which three saddle structures (B) part of storage tank are
positioned on the three I-beam bottom member (7) of the cage through bolted
joints. Other two are also supported in the similar way.
The Lifting means of the system of the invention is symmetrical in all respects; it
is designed in such a way so that it can support long seamless cylindrical
structure which is around 50m long and 4m in diameter along its length. The
storage tank is positioned through the saddle structure part of the storage tank
on provided bottom I beams platform by bolted arrangement.

A system for lifting and supporting of a long slender structure in particular
Feed Water Storage Tank of Deaeration system adopted in thermal power
plant, comprising one each right side cage and left side cage, each made
up of a plurality of ISMB beams which are inter-connected through a
truss member assembly, at least three truss members oriented
perpendicularly with each-other are welded between the two cages in all
four corners of the cages, the truss members are laced with V - shaped
bracings which are welded by keeping constant distances amidst all the
truss members in full length, a middle frame consists of four ISMB beams
which is welded to the system body such that centre of gravity of the
lifting structure coincides with the centre of gravity of the lifting means;
and at least two pairs of ropes attached at each corner of both the cages
through eye-hooks including also at the top it is two spreader beams
attached to both the sides of the cages at the top portion of the system.
The System as claimed in claim 1, wherein the middle frame is provided at
the centre of the system to ensure stability and to prevent imbalance
situation during lifting.
The system as claimed in claim 1, wherein the inter-connected truss
members hold the tank along its length and prevent horizontal sway of
the storage tank due to differential movements of crane hooks.
Dated this 20th day of JANUARY 2012.

The invention relates to a system for lifting and supporting of a long slender
structure in particular Feed Water Storage Tank of Deaeration system adopted in
thermal power plant, comprising one each right side cage and left side cage,
each made up of a plurality of ISMB beams which are inter-connected through a
truss member assembly, at least three truss members oriented perpendicularly
with each-other are welded between the two cages in all four corners of the
cages, the truss members are laced with V - shaped bracings which are welded
by keeping constant distances amidst all the truss members in full length, a
middle frame consists of four ISMB beams which is welded to the system body
such that centre of gravity of the lifting structure coincides with the centre of
gravity of the lifting means; and at least two pairs of ropes attached at each
corner of both the cages through eye-hooks including also at the top it is two
spreader beams attached to both the sides of the cages at the top portion of the
system.