FIELD OF INVENTION:
The present invention generally relates to manufacturing bends required for
water wall panels for high pressure boilers. The present invention more
particularly relates to bending operations in press. Still more particularly the
present invention relates to manufacturing of three bends with different
depths and pitch in a single press.
BACKGROUND OF INVENTION:
The conventional method of bending two bends in a same tube is carried out
by normal pressing using conventional die. In high pressure high temperature
steam generator furnace walls three bend offsets are envisaged according to
the requirement. As such there is no method available for the manufacturing
such bends in a single press as there is no gap between bends. In the
conventional method bends are done in bending machine using a clamp,
former and a follower jaw, this type of bend cannot be done in this machine
as there no gap for clamping the tube after the completion of the first bend
and the productivity of such process is very low. Hence there is a need to find
out an alternate method for manufacturing of three bends in a single press.
One or more drawbacks of conventional systems and process for a method for
improving yield strength of a workpiece and an apparatus are overcome, and
additional advantages are provided through the apparatus and a method as
claimed in the present disclosure. Additional features and advantages are
realized through the technicalities of the present disclosure. Other
embodiments and aspects of the disclosure are described in detail herein and
are part of the claimed disclosure.
The foregoing summary is illustrative only and is not intended to be in any
way limiting. In addition to the illustrative aspects, embodiments, and
features described above, further aspects embodiments, and features will
become apparent by reference to the drawings and the following detailed
description.

OBJECTS OF INVENTION:
Considering the above criteria, following analysis have been envisaged to
determine the objective of invention:
It is therefore an object of invention to propose a reliable and an effective
method of bending the three-bend offset with different depth and pitch on
boiler tubes.
Another object of invention is to propose a suitable die and an arrangement
for manufacturing.
A still further object of invention is to propose a suitable die holder for three
bends in a single press.
SUMMARY OF INVENTION:
Various objects, features, aspects, and advantages of the inventive subject
matter will become more apparent from the following detailed description of
preferred embodiments, along with the accompanying drawing figures in
which like numerals represent like components.
It is to be understood that the aspects and embodiments of the disclosure
described above may be used in any combination with each other. Several
of the aspects and 10 embodiments may be combined to form a further
embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any
way limiting. In addition to the illustrative aspects, embodiments, and
features described above, further aspects, embodiments, and features will
become apparent by reference to the drawings and the following detailed
description.
The present invention refers to the method of bending a three bend offset with
different depths and pitch in a single press. Accordingly, the work piece is fed
in between top rollers and bottom roller. Here for bending the offsets with
different depths and pitch an arrangement has been designed where the
bottom rollers are placed at different heights according to the requirement.

For placing the bottom rollers an arrangement has been made with predicted
depths envisaged in a high-pressure boiler by drilling holes on the additional
holders. The holes are drilled according to the diameter of the lock pin for
locking the rollers in the holder. The two numbers of bottom rollers are used
to feed the work piece and have an inbuilt curvature according to the diameter
of the tube on which we are going to bend, and it is also machined equal to
the radius of the bend required. The bottom rollers are placed on the holes
drilled on the holders according to the difference of depths required. With the
present arrangement, the difference of depths can be bent to “X” <= 75mm.
The top rollers are used to hold the work piece in the uni direction which also
has an in-built curvature according to the diameter of the tube. Now the die
is having two parts namely left quadrant die and right quadrant die. These
two quad dies can be assembled together and put it in the holder (not shown).
The assembly of left and right quadrants is moved downward to touch the
work piece. Now load is applied on the die to form a three bend in a single
press with the required offset.
BRIEF DESCRIPTIONS OF THE ACCOMPANYING DRAWINGS
It is to be noted, however, that the appended drawings illustrate only typical
embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other
equally effective embodiments. The detailed description is described with
reference to the accompanying figures. In the figures, the left-most digit(s) of
a reference number identifies the figure in which the reference number first
appears. The same numbers are used throughout the figures to reference like
features and components. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now
described, by way of example, and with reference to the accompanying figures,
in which
Figure 1 shows the work piece with different depth and pitch after bending

Figure 2 shows the arrangement of pressing operation
Figure 3 shows the arrangement with tube loaded before pressing
Figure 4 shows the arrangement with tube during pressing operation
The figures depict embodiments of the present subject matter for the purposes
of illustration only. A person skilled in the art will easily recognize from the
following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the
principles of the disclosure described herein.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION:
It should be noted that the description and figures merely illustrate the
principles of the present subject matter. It should be appreciated by those
skilled in the art that conception and specific embodiment disclosed may be
readily utilized as a basis for modifying or designing other structures for
carrying out the same purposes of the present subject matter. It should also
be appreciated by those skilled in the art that by devising various
arrangements that, although not explicitly described or shown herein,
embody the principles of the present subject matter and are included within
its spirit and scope. Furthermore, all examples recited herein are principally
intended expressly to be for pedagogical purposes to aid the reader in
understanding the principles of the present subject matter and the concepts
contributed by the inventor(s) to furthering the art and are to be construed as
being without limitation to such specifically recited examples and conditions.
The novel features which are believed to be characteristic of the present
subject matter, both as to its organization and method of operation, together
with further objects and advantages will be better understood from the
following description when considered in connection with the accompanying
figures.
As used in the description herein and throughout the claims that follow, the
meaning of “a”, “an” and “the” includes plural reference unless &e context

clearly dictates otherwise. Also, as used in the description herein, the
meaning of “in”' includes “in” and “on” unless the context clearly dictates
otherwise.
The terms "comprises", “comprising”, or any other variations thereof used in
the disclosure, are intended to cover a non-exclusive inclusion, such that a
device, system, assembly that comprises a list of components does not include
only those components but may include other components not expressly
listed or inherent to such system, or assembly, or device. In other words, one
or more elements in a system or device proceeded by “comprises... a” does
not, without more constraints, preclude the existence of other elements or
additional elements in the system, apparatus or device.
These and other advantages of the present subject matter would be described
in greater detail with reference to the following figures. It should be noted that
the description merely illustrates the principles of the present subject matter.
It will thus be appreciated that those skilled in the art will be able to devise
various arrangements that, although not explicitly described herein, embody
the principles of the present subject matter and are included within its scope.
The present invention refers to the method of bending a three-bend offset with
different depths and pitch in a single press.
Firstly, the two bottom rollers (05,06) are fixed in the holder (07) according to
the depth requirement. Accordingly, the work piece (09) is fed in between top
rollers (03,04) and bottom rollers (05,06). The two numbers of bottom rollers
(05, 06) is used to feed the work piece and to maintain the difference in the
depth and pitch required as per requirement, which has an inbuilt curvature
according to the diameter of the tube (09) which will be bended and is also
machined equal to the radius of the bend required. The holder (07) for the
bottom rollers (05,06) is designed with holes according to the size of the lock
pin (08) so that the required difference in the depth and the pitch is attained.
The bottom rollers (05, 06) and placed on the holder (07) and locked by placing
the lock pin (08). The top rollers (03, 04) is used to hold the work piece (09)
in the uni direction which also has an in built curvature according to the
diameter of the tube (09). The die has two parts namely left quadrant die (01)

and right quadrant die (02). The left and right quadrants (01,02) are machined
according to the radius of the bend required with an inbuilt curvature
according to the diameter of the tube (09). These two quadrant die can be
assembled together and put in the holder (10). The assembly of left and right
quadrants is moved downward to touch the work piece and pressure is
applied on the top rollers (03,04) to hold the work piece (09). A load is applied
on the die (01, 02) to form a three bend in a single press. Depending upon the
requirement, the left and right quadrant dies can also be separated to the
required distance by inserting a straight piece (not shown) with an inbuilt
curvature according to the diameter of the tube (05). The difference in the
depths (x) can also be modified by placing the bottom rollers (05,06) at
required holes according to the requirement and locking it by putting the lock
pin (08).
The same setup can be modified and used for tube diameters ranging from
38mm to 76.1mm, radius of bend ranging from 105mm to 225mm and
thickness of tube ranging from 4mm to 15.7mm. The difference in depths can
be bent up to “X” <=75.
Each of the appended claims defines a separate invention, which for
infringement purposes is “reorganized as including equivalents to the various
elements or limitations specified in the claims. Depending on the context, all
references below to the “invention” may in some cases refer to certain specific
embodiments only. In other cases, it will be recognized that references to the
“invention” will refer 1o subject matter recited in one or more, but not
necessarily all, of the claims.
Groupings of alterative elements or embodiments of the invention disclosed
herein are not to be construed as limitations. Each group member can be
referred to and claimed individually or in any combination with other
members of the group or other elements found herein. One or more members
of a group can be included in, or deleted form, a group for reasons of
convenience and/or patentability. When any such inclusion or deletion
occurs, the specification is herein deemed to contain the group as modified

thus fulfilling the written description of all groups used in the appended
claims.
With respect to the use of substantially plural and/or singular terms herein,
those having skill in the art can translate form the plural to the singular
and/or from the singular to the plural as is appropriate to the context and/or
application. The various singular/plural permutations may be expressly set
forth herein for sake of clarity.
It still be understood by takes within the art that in general, terms used
herein, and especially in the appended claims (e.g, bodies of the appended
claims) are generally intended as “open” terms (eg, the term “including”
should be interpreted as “including but not limited to,” the term “having”
should be interpreted as “having at least”, the term “includes” should be
interpreted as “includes but is not limited to” etc.)- It will be further
understood by those within the art that if a specific number of an introduced
claim recitation is intended, such an intent will be explicitly recited in the
claim, and in the absence of such recitation no such intent is present. For
example, as an aid to understanding, the following appended claim may
contain usage of the introductory phrases “at least one” and “one or more” to
introduce claims recitations. However, the use of such phrases should not be
construed to imply that the introduction of a claim recitation by the indefinite
articles “a” or “an” limits any particular claim containing such introduced
claim recitation to inventions containing only one such recitation, even when
the same claims includes the introductory phrases “one or more” or “at least
one” and indefinite articles such a “a” or “an” (e.g, “a” and/or “an” should
typically be interpreted to mean “at least one” or “one or more”); the same
holds true for the use of definite article used to introduce claim recitations. In
addition, even if a specific number of an introduced claim recitation is
explicitly recited, those skilled in the art will recognize that such recitation
should typically be interpreted to mean at least the recited number (e.g the
bare recitation of “two recitation,” without other modifiers, typically mean at
least two recitations, or two or more recitations). Furthermore, in those
instances where a convention analogous to “at least one of the A, B and C,

etc.” is used, in general such a construction is intended in the sense one
having skill in the art would understand the convention (eg. “a system having
at least one A, B and C etc. would include but not be limited to systems that
have A alone, B alone, C alone, A and B together, A and C together, B and C
together, and/or A, B and C together etc.). In those instances , where a
convention analogous to “at least one of A, B, or C, etc.” is used, in general
such a construction is intended in the sense one having skill in the art would
understand the convention (e.g., “a system having at least one of A, B or C”
would include but not be limited to systems that have A alone, B alone, C
alone, A and B together, A and C together, B and C together and/or A, B and
C together etc.). It will be further understood by those within the art that
virtually any disjunctive word and/or phrase presenting two or more
alternative terms, whether in the description, claims, or drawings, should be
understood to contemplate the possibilities of including one of the terms,
either of the terms or both terms. For example, the phrase “A or B” will be
understood to include the possibilities of “A” or “B” or “A and B”.
The above description do not provide specific details of manufacture or design
of the various components. Those of skill in the art are familiar with such
details, and unless departures from those techniques are set out, techniques,
known related art or later developed deigns and materials should be
employed. Those in the art are capable of choosing suitable manufacturing
and design details.
The technology used herein is for the expose of describing particular
embodiments only and is not intended to be limiting of the present disclosure.
It will be appreciated that several of the above-disclosed and other features
and functions, or alternative thereof, may be combined into other systems or
application. Various presently unforeseen or unanticipated alternatives,
modification, variation, or improvements therein.

WE CLAIM:
1. A device of bending a three-bend offset with different depth and pitch
in a single press comprising of:
- a pair of bottom rollers (05,06) to hold a tube (09) from below forming a
base;
- a base holder (07) and locking mechanism (08) to hold the pair of
bottom rollers (05,06);
- a pair of top rollers (03,04) to hold a tube (09) from above;
- a left (01) and right (02) quadrant dies are fixed onto a second holder
(10);
- wherein a load is applied on the pair of quadrant dies (01,02) to form a
three bend in a single press.

2. The device as claimed in claim 1, wherein said left (01) and right (02)
quadrant dies is altered to suit the requirement of the bend.
3. The device as claimed in claim 1, wherein the difference of the depth is
altered by realigning the locking mechanism (08).
4. The device as claimed in claim 1, wherein said left (01) and right (02)
quadrant dies are moved downwards on said tube (09) using hydraulic
cylinders for attaining the three-bend offset.