FIELD OF INVENTION
The present invention relates to an improved method of placing High pressure
outer casing (HPOC) inlet end of Steam turbine over Anchor bolt to its lowest position
during hydraulic testing by overhead crane having maximum hook height less than
minimum height required for assembly. More particularly the invention relates to an
assembly of HP Outer Casing (HPOC) Inlet End of steam turbine over Anchor bolt during
hydraulic testing in a workshop having overhead crane of lesser height and pertains to
development of new process for supporting HP outer casing inlet end at intermittent
height level, so that slings on Outer casing can be changed (from small length to long
length), while placing it on anchor bolt for its hydraulic testing.
BACKGROUND OF THE INVENTION
Steam turbine has broadly three modules i.e. high pressure turbine, intermediate
pressure turbine & low pressure turbine. In high pressure turbine, outer casing (high
pressure) consists of two parts i.e. HP Outer Casing-Inlet end & HP Outer Casing- Exhaust
end. HP turbine has to work at high steam pressure during its normal working. Hence,
hydraulic testing at defined test pressure is carried out on these casings to ensure its leak
proof-ness and casting soundness.

Hydraulic testing of HP outer casing is done in two stages. In first stage hydraulic
testing of HPOC inlet end is done and in second stage HPOC inlet end and exhaust end is
tested in assembled condition.
For hydraulic testing of HP inlet end, it is required to close all openings of casing
with technological plugs/flanges by welding or by fitting. For hydraulic testing, anchor bolt
is fitted with bottom nut and bottom flange (Refer Fig.1).
This length of anchor bolt & HP outer casing inlet end is such that after lifting HP
outer casing inlet end with sling using overhead crane, it is not possible to place outer
casing inlet end to its lowest portion on anchor bolt. Crane height is limitation in this case.
OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose an improved method of
placing High pressure outer casing (HPOC) inlet end of Steam turbine over Anchor bolt to
its lowest position during hydraulic testing by overhead crane having maximum hook
height less than minimum height required for assembly which is capable of eliminating
limitation of crane height.

Another object of the invention is to propose An improved method of placing High
pressure outer casing (HPOC) inlet end of Steam turbine over Anchor bolt to its lowest
position during hydraulic testing by overhead crane having maximum hook height less
than minimum height required for assembly which eliminates the need of new facilities
and place with higher crane height avoiding substantial capital investment.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1: Shows an ideal case of complete arrangement of HP outer casing inlet end
placed over Anchor bolt and the said bolt fitted with bottom nut and bottom
flange.
Fig. 2: Shows complete arrangement where maximum crane hook height from floor
is less than required, when anchor bolt is fitted with bottom nut and bottom
flange assembly and four base supports are placed in position to support
HPOC inlet end.
Fig. 3: Shows H.P.O.C. inlet end is lifted using small length sling for placing over
base support according to the invention.
Fig. 4: Shows H.P.O.C. inlet end being supported over Base support when small
length slings are replaced by long length slings placed on crane hook and HP
outer casing inlet end according to the invention.

Fig. 5: Shows outer casing inlet end with long slings placed to its lowest position on
Anchor bolt according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Referring to fig.1, arrangement shows following major components:
1. Anchor Bolt (2) assembled with Bottom flange (5) & bottom Nut (6).
2. H.P. Outer Casing inlet end (1).
3. Slings to lift H.P. Outer Casing inlet end (7).
4. Overhead Crane (4).
Following dimensions are marked in Fig.1:
Hcr = Height of crane Hook from Ground level.
Hsl = Height of Slings (while lifting).
Hoc = Height of H.P. Outer Casing inlet end.
Hab = Height of Anchor Bolt.
Hbn = Height of Bottom nut & bottom flange assembly.
To place H.P. Outer Casing Inlet End (1) over Anchor Bolt (2) to its lowest position,
following condition is to be fulfilled:

Height of Crane Hook (3) from ground level (Hcr) should be more than sum of
Height of Anchor Bolt (Hab), Height of H.P. Outer Casing Inlet End (Hoc) & Sling Height
(Hsl) (while lifting).
Mathematically, Hcr > Hab + Hoc + Hsl
Height of Sling should be such that after lifting H.P. Outer Casing Inlet End over
Anchor bolt, it should place H.P. Outer Casing Inlet End to its lowest position on Anchor
bolt (without stuck on top of Anchor bolt). This means, Sling Height (while lifting) (Hsl)
should be more than {Height of Anchor bolt (Hab) - Height of Bottom nut & bottom flange
assembly (Hbn) - Height of H.P. Outer Casing Inlet End (Hoc)}.
Mathematically, Hsl > Hab - Hbn - Hoc
Considering above conditions, in actual case, Maximum height of crane Hook (3)
from Ground level (Hcr) is less than sum of Height of Anchor Bolt (Hab), Height of H.P.
Outer Casing Inlet End (Hoc) & Sling Height (Hsl).
In actual case :- Hcr < Hab + Hoc + Hsl

To overcome above limitation, a new work place needs to be developed with
required crane height, which calls for substantial capital investment & time required for
creating required facility.
To save cost & time, an innovative process of assembly using existing resources &
crane height was envisaged.
Accordingly, a new process has been developed for placing HP outer casing inlet
end (1) over anchor bolt (2) (for its hydraulic testing) to its lowest position. This
comprises mainly of following items:-
a. Base support (S1) (Height – H1) - Qty - 1 No.
b. Base support (S2) (Height - H2) - Qty - 1 No.
c. Base support (S3) (Height - H3) - Qty - 2 No.
d. Slings with Small length (4) (Height while lifting - Hsl-1) - Qty-1 No.
e. Slings with Long length (5) (Height while lifting - Hsl-2) - Qty-1 No.
It is proposed to use two type of slings (Small length (8) & Long Length (9)) for
placing HP outer casing inlet end (1) over anchor bolt (2) to its lowest position. Small
lenqth sling (8) is to be tied to the crane hook and HPOC for lifting HP outer casing inlet

end (1) from floor & placing it over Anchor Bolt (2). But as Sling (8) length is small HP
outer casing inlet end (1) cannot be placed to its lowest position on anchor bolt (2). For
this constraint, four Supports [S1, S2, S3 (2 Nos.)] have been developed for supporting
HPOC inlet end (1) and disposed around anchor bolt (2) during its placement over anchor
bolt (2) with Small length slings (8) tied to crane hook (3) and HPOC inlet end (1). Now
these four Base supports [S1, S2, S3 (2 Nos.)] heights are so designed that after lifting
H.P. Outer casing (1) with these small height Sling (8), Outer casing can be supported on
these supports. After supporting HP outer casing inlet end (1) over supports [S1, S2, S3
(2Nos.)], small slings (8) are removed & long slings (9) are put in Hook (3) & casing (1).
Engaging these long slings (9) with crane hook (3) and casing (1), HP outer casing inlet
end (1) is again lifted. Supports [S1, S2, S3 (2Nos.)] are removed from below & then HP
outer casing inlet end (1) is placed to its lowest position on anchor bolt (2).
In this system, Sum of Height of Small length Slings (Hsl-1), Height of H.P. Outer
Casing Inlet End (Hoc) & Height of Base Support is more than Height of Anchor Bolt
(Hab).
Hsl-1 + Hoc + Hsupport > Hab

Also Maximum height of crane Hook from Ground level (Hcr) is more than Sum of
Height of Small height Slings (Hsl-1), Height of H.P. Outer Casing Inlet End (Hoc) & Height
of Anchor Bolt (Hab).
Hcr > Hsl-1 + Hoc + Hab
H.P. Outer Casing Inlet End is lifted with small height Slings & placed through
Anchor Bolt, on Base Supports. Now Small height slings are removed from hook & long
height slings are taken. With long height slings, H.P. Outer Casing Inlet End is lifted. All
base supports are removed.
Height of Long length slings (Hsl-2) is such that Sum of Height of Long length
Slings (Hsl-2) & Height of H.P. Outer Casing Inlet End (Hoc) is more than Difference of
Height of Anchor Bolt (Hab) & Height of Bottom nut & bottom flange assembly (Hbn).
Hsl-2 + Hoc > Hab -Hbn
With this H.P. Outer Casing Inlet End is placed to its lowest position on Anchor bolt.

WE CLAIM
1. An improved method of placing High pressure outer casing (HPOC) inlet end of
Steam turbine over Anchor bolt to its lowest position during hydraulic testing by overhead
crane having maximum hook height less than minimum height required for assembly, the
said method comprising;
disposing a plurality of supports (S1, S2, S3) around the anchor bolt (2) to facilitate
the placement of a HPOC inlet end (1) of a steam turbine over the said supports;
tying a plurality of small length slings (8) with crane hook (3) of a overhead crane
(4) at one end and with said high pressure outer casing inlet end (1) at the other end to
lift the said casing (1) from floor;
placing the said High pressure outer casing inlet end over the said supports;
removing small length slings from the crane hook (3) and the casing (1);
tying a plurality of long length slings (9) with said crane hook (3) at one end and
with the said casing at the other end to lift the HP outer casing inlet end (1); wherein the
HPOC inlet end (1) is lifted up and the said supports are removed when the HPOC inlet
end is placed to its lowest position on anchor bolt (2).
2. The improved method as claimed in claim 1, wherein the number of supports to
hold the casing (1) are Four [S1, S2, S3 (2Nos.)].

3. The improved method as claimed in claim 1, wherein the number of slings tying the
casing (1) with crane hook (3) are two for both small length slings (8) and long length
slings (9).