FIELD OF THE INVENTION
The present invention relates to a rolling device for unrestricted welding of stator
frames during fabrication of the stator frame.
BACKGROUND OF THE INVENTION
High rating Stator Frames for example 250MW and 500MW 600, 660, 800 MW,
are generally cylindrical in shape with ribs and flanges welded on its surface. The
flanges and ribs, which are to be assembled on the stator frame foul with the
rollers during the assembly. Due to this reasons it is not possible to roll the job
(stator frame) to all positions that are necessary for welding, (see Figure 1).
Although the cylinder of the stator frame can be rotated to all convenient
positions for welding on rollers ONLY before the flanges and ribs are assembled,
after the assembly of the ribs and flanges, the stator frame needs to be turned
again from time-to-time into different positions, in order to bring it into positions
that are required for welding. This is a time consuming, costly and undesirable
process.
Such a prior art process increases the labour costs, shop floor time, cost of
manufacturing, and supervision.
OBJECTS OF THE INVENTION
It is therefore, the object of this invention to propose a rolling device for
unrestricted welding of stator frames by converting the welding from 3G, 4G and
5G position to 1G position.
Another object of the invention is to propose a rolling device for unrestricted
welding of stator frames by converting the welding from 5G position to 1G
position, which eliminates the problem of fouling of ribs and base plate with
rollers.
A still another object of the invention is to propose a rolling device for
unrestricted welding of stator frames by converting the welding from 5G position
to 1G position, which ensures simultaneous assembly of base plate and beams in
one setting.
A further object of the invention is to propose a rolling device for unrestricted
welding of stator frames by converting the welding from 5G position to 1G
position, which allows reduction of labour cost, loss of shop floor time, cost of
manufacturing, supervision.
SUMMARY OF THE INVENTION
Accordingly, there is provided a rolling device for unrestricted welding of stator
frames by converting the welding from 5G, 3G, 4G position to 1G position,
comprising at least a pair of metal rings, each ring disposed at proximal and
distal end of a stator frame of a turbogenerator; at least two pairs of pipe
members, each pair is weldably joining the ring to the stator frame; a pair of
roller, each controllably rotatable by an electrical motor, each roller being
attachable to the subassembly of the ring and pipe member such that the entire
assembly of the stator frame ring, and the pipe can be rotated based on
simultaneous measurement of the centre line of the stator frame.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - a prior art device for welding of stator frames during stator
fabrication.
Figure 2 - shows a rolling type device according to the invention for holding
and rotating stator frame during welding including fabrication of
the frame assembly.
Figure 3 - shows sectional views of the major components (ring and pipe) in a
first sub-assembly according to the invention.
Figure 4 - shows a second sub-assembly of the inventive device according to
the invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention, the rolling device for unrestricted welding of stator
frames, as shown in figure 2, consists of a fabricated assembly of (a) Ring (2)
Pipe (1), which is welded to both ends of the job (3) (TG Stator Frame) by
means of the Pipes (1).
The device is then supported on at least two rollers (4) of an electrical rotator
having a Controller (not shown).
The speed and direction of rotation of the rollers (hence, the device and job) are
controlled by the electrical rotator including the controller of the rotator.
The unique idea in this case is that the cylinder (2) of the rolling device is not
directly attached/welded to the stator frame (3), but there is a pipe (1) in
between.
The pipe (1) serves two purposes:
(1) The entire ring (2) need not be welded to the stator frame (3), only the
pipe (1) needs to be welded before use and gouged out after use.
(2) The gap between the ring (2) of the rolling device and the stator frame
(3) is essential for dimensional measurement of the stator frame (3).
In this space angles (5) are welded and a plurality of piano wire with weight (6)
are hung in order to ascertain the centre lines of the stator body (3).
According to this invention, the rolling device comprises a fabricated assembly of
at least two rings (2), at least four pipes (1) and at least two rollers (4). The
pipes (1) are welded to the side walls of stator frame at both ends.
The rolling device is then mounted on the rollers (4) of the rotator and is turned
by the rollers (4) in desired direction as per the requirement.
The size of the ring of the rolling device is selected taking into account the
maximum size of the cylindrical job (stator frame) and the contact area of the
rollers (4). For example, the size of the ring can be selected as four meters.
Both the rings (2) should be of same dimensions.
The pipes (1) in-between the ring (2) and the job (side wall of stator frame) are
of same sizes and selected so as to hold the job (3) with ring (2).
The pipe length is selected in a range of 15 mm to 25 mm in order to maintain a
gap between the job (3) and the ring (2).
After the complete fabrication of the job (assembly and welding), the rolling
device can be removed by gouging out the pipes (of the device).
Besides this, propose dimensioning of the stator frame (3) can be done
simultaneously. The gap between the ring (2) and the stator frame (3) is utilized
for dimensional measurement of the stator frame (3).
In this space, angles (5) are welded and piano wire with weight (6) is hung in
order to ascertain the centre lines of the stator body, which is used as reference
to other dimensions. Thus, dimensional accuracy of the job (3) is ensured.
The device is applicable for other extended field of applications:
(1) The invention can be used for unrestricted welding of cylindrical jobs
(stator frames), as by this 5G, 4G, 3G position can be converted to 1G
position easily.
The inaccessible areas can be easily accessed for welding.
(2) The invention can be used for easy assembly of cylindrical type of jobs.
Using this, the center lines can be easily ascertained and can be used as
reference to other dimensions. By using the device, various items at
different positions can be easily assembled on the job.
(3) The invention is not only limited to cylinders with circular base, but can
be extended to assembly and welding of cylinders with different cross-
sections.
(4) The invention can be applied for the inspection of the cylindrical jobs at
various positions.
(5) Beside this, the invention can be used for all type of cylindrical jobs and
does not require any type of holes to be drilled on the job in order to
fasten it with the device.
For example, in an illustrated embodiment of the invention, the job is being
welded to the pipes, so requirement of drilling holes on the job so as to fasten
with the device does not arise at all.
Advantages of the inventive device are as follows:-
(1) The device allows conversion of the 5G, 4G, 3G position into 1G position,
hence eliminates the welder fatigue. Accordingly, the welders qualified in
1G position can be engaged during welding.
(2) Simultaneously assembly and welding can be done easily, which
improves productivity significantly.
(3) Inspection, painting and related tasks can be performed on any
cylindrical jobs easily.
(4) Continuous crane/handling requirement for changing positions during
fabrication is eliminated.
Thus, the cycle time is reduced significantly, which results in minimization of the
labour costs, loss of shop floor time, cost of manufacturing, supervision costs
effectively.
(5) The possibility of fouling of the projections on the cylindrical jobs (eg.
Baseplate, flanges etc. in case of stator frame) with the rollers is
completely eliminated.
(6) A single device can be used for cylindrical jobs of different cross-sections
irrespective of circular base if the maximum dimensions of the jobs are
similar.
WE CLAIM
1. A rolling device for unrestricted welding of stator frames by converting the
welding from 5G,4G, 3G position to 1G position, comprising:
- at least a pair of metal ring (2), each ring (2) disposed at proximal and
distal end of a stator frame (3) of a turbogenerator;
- at least two pairs of pipe members (1), each pair (1) is weldably joining
the ring to the stator frame (3);
- a pair of roller (4), each controllably rotatable by an electrical motor,
each roller (4) being attachable to the subassembly of the ring and pipe
member (1,2) such that the entire assembly of the stator frame (3), ring
(2), and the pipe (1) can be rotated based on simultaneous
measurement of the centre line of the stator frame (3).
2. The device as claimed in claim 1, wherein a gap is maintained between the
ring (3) and the stator frame (3), and wherein the gap is provided with
metal angles (5) including piano wires (6) to facilitate the process of making
measurements in order to maintain dimensional accuracy of the fabrication
process.
3. The device as claimed in claim 1 or 2, wherein the length of the rings (2) is
selected at a value of around 4-meters.
4. The device as claimed in claim 1, wherein the length of the pipe members
(1) is selected between 150mm to 250mm.
5. The device as claimed in claim 1, wherein the stator frame is for a
turbogenerator having capacity between 250MW and 500MW, 600, 660,
800MW.
6. A rolling device for unrestricted welding of stator frames by converting the
welding from 5G,4G, 3G position to 1G position, as substantially described
and illustrated herein with reference to the accompanying drawings.

ABSTRACT

The invention relates to a rolling device for unrestricted welding of stator frames
by converting the welding from 5G, 4G, 3G position to 1G position, comprising at
least a pair of metal rings (2), each ring (2) disposed at proximal and distal end
of a stator frame (3) of a turbogenerator; at least two pairs of pipe members (1),
each pair (1) is weldably joining the ring to the stator frame (3); a pair of roller
(4), each controllably rotatable by an electrical motor, each roller (4) being
attachable to the subassembly of the ring and pipe member (1,2) such that the
entire assembly of the stator frame (3), ring (2), and the pipe (1) can be rotated
based on simultaneous measurement of the centre line of the stator frame (3).