FIELD OF THE INVENTION
The present invention relates to a panel bending roller used in Panel bending
machine for bending boiler water wall panels.
BACKGROUND OF THE INVENTION
In a boiler, water wall panels are used to absorb the heat generated in the
combustion process taking place in the furnace. Water circulating through the
tubes that form the furnace wall lining, absorb the heat generated and in turn
generates steam by evaporation of a part of the circulating water. The water
walls usually consist of vertical tubes arranged in substantially tangential
direction being connected at top and the bottom to the headers. These tubes
receive the water from a boiler drum via a plurality of down comer pipes
connected between the bottom of the drum and the lower headers. At the
bottom of the furnace, the water wall panels are bent to collect the ash produced
in the furnace, this region of the water wall panel is called the hopper region. To
manufacture these bends, a panel bending machine is used. The known panel
bending machines are equipped with tools capable to bend only panels which are
formed of tubes upto 51 mm OD, and radius of 248°. Thus, the prior art fails to
provide tools for bending tubes of water wall panel having tube diameter above
51 mm with radius of 406°. Hence there exists a need to propose a tool to bend
tubes of all sizes for water panels.
OBJECT OF THE INVENTION
It is therefore the object of the invention to propose a being roller in a panel
bending machine for bending tubes of boiler water panels.
SUMMARY OF THE INVENTION
Accordingly, there is provided - A bending roller in a panel bending machine for
bending tubes of higher diameter with large bend radius forming boiler water
panels, comprising an outer ring formed of metal pipes and having diameter
corresponding to a required bend radius; an inner ring formed of identical
material and having a diameter match the diameter of a shaft of the panel
bending machine; a gusset ring having an inner and outer diameter, the inner
diameter is welded to the outer diameter of the inner ring, the outer diameter
being welded to the inner diameter of the outer ring; and a plurality of gusset
plate welded to the ring assembly to form the bending roller.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure -1 shows a bending roller according to the invention.
DETAIL DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
As shown in fig. 1, an outer ring (1) is formed of metal pipes and having a
diameter corresponding to the diameter of bend required for the tubes forming
the water panels. An inner ring (2) formed of identical materials and having a
diameter matching with that of the shaft of the bending machine on which the
roller is to be mounted. A gusset ring (3) having an inner diameter and an outer
diameter respectively welded to the outer diameter of the inner ring (2) and the
inner diameter of the outer ring (1). A plurality of gusset plate (4) welded to the
ring assembly (1,2) to form the bending roller.
Example
For bending tubes of boiler water panel, having tube diameter and bend radius
of respectively 63.5 mm and 406°, the required length of the roller was
3000mm. Due to large size, the roller was produced in six segments with a
length of 500mm each. The roller requires an OD of F730 and ID of F280.
Accordingly, two concentric pipes were welded together to get the required
dimensions. For additional strength, a plurality of gusset plates were welded
between the two pipes. The roller was configured with OD of F730. The
dimension of the roller was further optimized by considering spring back of the
water wall panel after bending. 10% spring back was considered for bending
water wall panel. The required radius of bend is 406°. However, a designed bend
was selected at a radius of 365 °. After bending, the panel achieves its required
radius of 406°, due the spring back effect.
WE CLAIM
1. A bending roller in a panel bending machine for bending tubes of higher
diameter with large bend radius forming boiler water panels, comprising:
- an outer ring (1) formed of metal pipes and having diameter
corresponding to a required bend radius;
- an inner ring (2) formed of identical material and having a diameter match
the diameter of a shaft of the panel bending machine;
- a gusset ring (3) having an inner and outer diameter, the inner diameter
is welded to the outer diameter of the inner ring (2), the outer diameter
being welded to the inner diameter of the outer ring (1); and
- a plurality of gusset plate (4) welded to the ring assembly (1,2) to form
the bending roller.

The invention relates to a bending roller in a panel bending machine for bending
tubes of higher diameter with large bend radius forming boiler water panels,
comprising an outer ring (1) formed of metal pipes and having diameter
corresponding to a required bend radius; an inner ring (2) formed of identical
material and having a diameter match the diameter of a shaft of the panel
bending machine; a gusset ring (3) having an inner and outer diameter, the
inner diameter is welded to the outer diameter of the inner ring (2), the outer
diameter being welded to the inner diameter of the outer ring (1); and a plurality
of gusset plate (4) welded to the ring assembly (1,2) to form the bending roller.