FIELD OF THE INVENTION
The present invention relates to a method of edge preparation on elbows. In
particular, invention relates to a method of edge preparation of elbows in a vertical
boring machine with a single setting for change of flow directions in high pressure
boilers. The invention further relates to an apparatus for preparation of edges on both
sides of an elbow with a single setting in a vertical boring machine.
BACKGROUND OF THE INVENTION
During edge preparation of high thickness elbows having outside diameter ranging
from 273mm to 406mm, and a thickness varying from 38mm to 45mm the elbow is
fixed in a horizontal boring machine. A setting time is required at each end of the
elbow separately. Hence, the total time required to make the edge preparation on
both ends of the elbow is more in the horizontal boring machine. A plurality of elbows
are used for flow change directions in high pressure boilers and ultra high pressure
boilers. These edge prepared portions of the elbows are used for welding with other
straight pipes for boiler applications.
Since the time taken to complete the edge preparation process is almost 8 hours per
elbow for both ends including the setting time, it is important to reduce the time as
compared to that of prior art process. Further, it is necessary to produce quality
product in a vertical boring machine instead of horizontal boring machine used in prior
art.

OBJECTS OF THE INVENTION
It is therefore an object of the present invention to a method of edge preparation of
elbows in a vertical boring machine with a single setting for change of flow directions
in high pressure boilers.
Another object of the present invention is to propose an apparatus for preparation of
edges on both sides of an elbow with a single setting in a vertical boring machine.
A further object of the present invention is to mount the elbows on the apparatus in
such a way so as to prevent re-setting of the elbows with base plate of the apparatus.
A still further object of the present invention is to fix the elbow on the apparatus in a
simple manner for each side edge preparation.
SUMMARY OF THE INVENTION
Accordingly, in one aspect of the invention, there is provided an apparatus for
preparation of edges on both sides of an elbow with a single setting in a vertical
boring machine, comprising a base plate mountable on a table of the vertical boring
machine with T bolts and nuts; at least two leg plates welded vertically on the base
plate, the horizontal distance between the leg plates being 560mm for an elbow
having the maximum outside diameter of 406 mm with clearance on either side, one
each angle plate connected with vertical plate by connecting pins on provided either
side; two bearings inserted in each of the angle plate for easy rotation of the angle
plate;

Two V block seating plate permanently welded on the top and bottom of the angle
plate in which the bottom V blocks are positioned by slotted holes provided on the V
block seating plate, a plurality of studs welded on the bottom side of the V block, the
top side of the bottom V block being provided with internal threads on the upper
portion for connecting the top V block using the studs and lock nuts for arresting the
degrees of rotational freedom on either side; and two clamping plates permanently
positioned on the top and bottom side of the angle plate which in turn is connected to
the base plate for strengthening the apparatus during edge preparation.
According to a second aspect of the invention, there is provided a method of edge
preparation of elbows in a vertical boring machine with a single setting for change of
flow directions in high pressure boilers. As per the inventive method, the elbow which
is to be edge prepared is mounted between the top and bottom V block can be
adjusted to suit the various outside diameter of the elbow ranging from 273 mm to
406 mm.
BRIEF DESCRIPTION OF THE ACCOMPANY DRAWINGS
Figure 1 - Base plate (01)
Figure 2 - Leg plate (02)
Figure 3 - V block seating plate (03)
Figure 4 - Angle plate (04)
Figure 5 - V block bottom (05)
Figure 6 - V bottom top (06)
Figure 7 - Bearing cup (07)
Figure 8 - Clamping plate (08)
Figure 9 - Connecting pin (09)
Figure 10-Assembly of apparatus with work piece in position for edge preparation

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
According to the present invention, the edge preparation is carried out at both ends of
the elbow with a single setting in a vertical boring machine.
Figures 1 to 9 show the individual constituting components of the inventive apparatus
for edge preparation. Figure 10 shows assembled apparatus with components
connected to a work piece in position.
As shown in figure 10, the base plate (01) is welded with two nos of leg plate (02)
and the distance between the two leg plates is 560 mm. The dimension is derived
based on the outside diameter of the elbow (13) and the clearance required for
mounting the angle plates (04). The angle plates (04) are connected with leg plate
(02) by means of pin (09) which is fixed on the bearing housing (07). The bearing
housing is not visible in the figure 11 and hence it is shown in figure 10 in the another
view. Again referring to figure 11, a bolt (12) is inserted on the top of the leg plate on
either side to present the rotation of the pin (09). The angle plates are provided with
circular holes so that the entire device can be taken by crane and easily positioned on
the vertical boring machine table (not shown).
Referring to figure 10, two nos of V block seating plate (03) are welded on the bottom
and top side of the angle plate (04). Bottom V blocks (05) is provided with stud in the
bottom to seat in the V block seating plate (03). Bottom V blocks (05) is provided with
tapped holes at the top for the positioning the work piece (13) by means of bolts (10)
and tightened by nut (11). The top V block (06) are directly positioned on the top side
of the work piece (13) which movements are arrested by means of stud (10)

and nut (11). Now the entire device is readily for fixing in the vertical boring machine
table. After fixing the device in the machine table, the angle plate can be rotated by
means of bearing housing (07) and it is locked by studs on the clamping plate (08)
which are permanently welded on the top and bottom side of the angle plate.
After one side edge preparation is finished, the other side is positioned by loosening
the bolts on the clamping plate (08) and the angle plate (04) is easily rotated on the
other side to perform the edge preparation on the other end of the work piece (13).
According to the invention, time for edge preparation of the elbows in a vertical
boring machine can be reduced to half of the time than that of the prior art method of
edge preparation for elbows used in links and header of high pressure and ultra high
pressure boilers.

WE CLAIM :
1. An apparatus for preparation of edges on both sides of an elbow with a single
setting in a vertical boring machine, comprising :
a base plate mountable on a table of the vertical boring machine with T bolts
and nuts;
at least two leg plates welded vertically on the base plate, the horizontal
distance between the leg plates being 560mm for an elbow having the
maximum outside diameter of 406 mm with clearance on either side;
one each angle plate connected with vertical plate by connecting pins on
provided either side;
two bearings inserted in each of the angle plate for easy rotation of the angle
plate;
two V block seating plate permanently welded on the top and bottom of the
angle plate in which the bottom V blocks are positioned by slotted holes
provided on the V block seating plate, a plurality of studs welded on the
bottom side of the V block;
the top side of the bottom V block being provided with internal threads on the
upper portion for connecting the top V block using the studs and lock nuts for
arresting the degrees of rotational freedom on either side; and two clamping
plates permanently positioned on the top and bottom side of the angle plate
which in turn is connected to the base plate for strengthening the apparatus
during edge preparation.
2. A method of edge preparation of elbows in a vertical boring machine with a
single setting for change of flow directions in high pressure boilers, the method
comprising the steps of :

providing a base plate (01) having four slots to fix the elbow in the vertical
boring machine table;
at least two leg plates (02) positioned on the base plate (01) to have at least
two angle plates (04) welded with slotted bottom of corresponding number of
clamping plate (03);
placing a bottom V block (05) by means of screws on the bottom side of said
bottom V blocks (05) connected to the bottom clamping plate (03);
placing a work piece (13) on the bottom V blocks and fastening by means of
studs (10) and nut (01) with the top V block (06); and
adjusting the position of the elbow by rotating the angle plate (04) by a
bearing housing (07) so that the edge preparation is completed one by one in a
single setting.

ABSTRACT

The invention relates to an apparatus for preparation of edges on both sides of
an elbow with a single setting in a vertical boring machine, comprising : a base
plate mountable on a table of the vertical boring machine with T bolts and
nuts; at least two leg plates welded vertically on the base plate, the horizontal
distance between the leg plates being 560mm for an elbow having the
maximum outside diameter of 406 mm with clearance on either side, one each
angle plate connected with vertical plate by connecting pins on provided either
side; two bearings inserted in each of the angle plate for easy rotation of the
angle plate; Two V block seating plate permanently welded on the top and
bottom of the angle plate in which the bottom V blocks are positioned by
slotted holes provided on the V block seating plate, a plurality of studs welded
on the bottom side of the V block, the top side of the bottom V block being
provided with internal threads on the upper portion for connecting the top V
block using the studs and lock nuts for arresting the degrees of rotational
freedom on either side; and two clamping plates permanently positioned on the
top and bottom side of the angle plate which in turn is connected to the base
plate for strengthening the apparatus during edge preparation.