FIELD OF INVENTION
The present invention relates to an arrangement for absorbing relative
movement between components amidst dusty and radiant heat environment of a
circulating fluidised bed combustion (CFBC) boiler. More particularly, the invention
relates to an arrangement to withstand even sudden surge pressure.
BACKGROUND OF THE INVENTION AND PRIOR ART
Boilers are having different types of components. Each component is
expanding/moving depending upon the temperature and type of supporting
arrangement. Some of systems in boiler are fan to combustor through air-preheater
which carries cold and hot air, boiler outlet to chimney through number of components
which carries hot flue gases. Cyclone to loop seal, loop seal to circulating fluidised bed
(CFB) combustor return leg, fluidised bed heat exchanger (FBHE) to CFB combustor
return leg, ash cooler to combustor and combustor to ash cooler. The above five
arrangements carries very hot, pressurised multiphase fluids. Hence 100% leak
tightness connection is to be ensured to prevent flowing out of material, loss of material
and most importantly for personal safety. The cross sectional size of components in
this systems are 2.5 meter, movements in three perpendicular axes are 200 mm, 40

mm, 40 mm for a typical project. Environment surrounding this system is very dusty,
hot, have corrosive particles, and having radiant heat source.
Earlier Fabric type expansion systems and circular metallic bellow type expansion
system were used in these locations for absorbing relative movement. The positives
points of fabric types are, (i) accommodating space is bare minimum for a designed
axial, laterals movement combinations compared to other expansion system, (ii) Time
required for installation and dismantling is minimum. (iii) No welding is envisaged.
On the other hand, the fabric type expansion joints, (i) Unable to withstand,
sudden surge pressure, produced in the return leg lines, particularly at fuel mixing
return Leg line. (ii) Requires skilled man power and equipment for making Endless
fabric, from open end connection (iii) Elaborate tightening of fasteners for hundred
percent leak tightness (iv) Metals in the fabric joint system is expanding and fasteners
are getting loosened, which cannot be retightened during operation. (v) Fabric joint
requires continuous cooling flow medium, outside for proper functioning, wherein boiler
heat sources are in proximate region, and corrosive dust particles fall over it. (vi) Pin -
Hole get formed even if small iron particles fall over it accidently, Material will start
leaking from this pin hole, leading to enlargement of hole and burning of fabric in short

time, and planned isolation is not possible (vii) It is not taking any portion the dead
weight of connected component, requiring separate supporting arrangement.
Another type, the circular metallic bellow type overcomes most of the difficulties
of fabric type. However circular metallic bellows having the following drawbacks: (i)
Manufactured using forming methods, which requires special machineries (ii) Higher
grade materials are used for increasing formability (iii) Required to supply in full circular
piece. So metallic bellow to be sub-assembled with the connecting components at floor
level, then assemble the connecting components with other components. During
replacement/rectification, the sub assembly to be dismantled and to be rectified at floor
level. (iv) Welding is difficult, if the bellows are sent in segment instead of full.
In order to overcome the drawbacks said above, there is a need to find out an
alternate method of absorbing the relative movement between the components.
PRIOR ART
More than 2000 patents were searched related to this topic. Among them, the
following patents found to be relevant to the prior art claimed were studied in detail.
These are related to present subject matter but not relevant to the present invention.

US2100238A - Metallic expansion joint.
US4942710A - Fire-rated expansion joint having three degrees of freedom.
US3460856A - Expansion joints for conduits.
US2742384A - Thermal insulating expansion joint for pipes.
US2807480A - Flexible resilient sleeve type joint with internal tie means.
US2886885A - Expansion joint and method of making same.
US4059292A - Expansible coupling.
US4299414A – Expansion Joint.
US4273365A - Expansion joint and fabric there for.
US4235460A - Expansion joint.
US4140338A - High temperature expansion joint.
US4063755A - Compensators or expansion joints.
CN203131302U - Fabric compensator suitable for gas desulfurization system.
CN201803042U- Non-metallic expansion joint for boiler material.
CN201416725Y - Isolated corrosion-proof metal corrugated pipe expansion joint.
CN201723905U - External compression-type compound expansion joint for coal
gasification device.
CN2819005Y - Assembled soft thermal-insulative cover.
CN101487552A - Novel non-metal expansion joint.

OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose an arrangement for
absorbing relative movement between components amidst dusty and radiant heat
environment of a circulating fluidised bed combustion boiler, which is able to arrest the
upward and downward vertical axis movement and inward and outward horizontal
movement of the components of the boiler as well as sudden surge pressure generated
within the system.
SUMMARY OF THE INVENTION
Accordingly, the present art have loop-seal connecting duct connected with loop
seal at the top. At the bottom combustor connecting duct is connected with combustor.
The relative movement between the loop–seal connecting duct at the top and
combustor connecting duct at the bottom are to be taken care by the following method
of connection.
The Invention is related to compensator and arrangement particularly in boiler
field, for absorbing relative movement between the connecting Components. The loop
seal connecting duct on the top and combustor connecting duct at the bottom are
independently linked by welding the slide-II on the top and welding the slide-I at the

bottom which are having annular clearance to take care of the all the degrees of
freedom of the upper part and lower part in such a way that the slide-II and slide-I are
connected with upper profile and lower profile matching arrangement respectively with
help of lateral fixing assembly with the profile matching plates both at the top and
bottom are welded with standard channels and expansion bellows and floating duct
already welded with drain assembly to remove the accumulated bed materials between
the gap. Locking plates are welded on all sides with two rectangular plate per side both
top and bottom which are interconnected by locking screw and nut to ensure vertical
and lateral alignment. Now the entire arrangement is capable of withstanding the 200
mm upward and downward vertical axis movement and 40 mm inward and outward
horizontal movement of the loop seal connecting duct and combustor connecting duct.
This entire arrangement withstands even sudden surge pressure due to the robustness
of construction, taking self-weight due to self-stiffness property of bellows, function at
even dusty and radiant heat environment, since metallic material is used at
surrounding. Top sealing air and bottom sealing air provided with 2 inch outer diameter
pipes to send compressed air at the pressure of 1kg sq.cm to avoid multiphase fluid
leakage.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows the main arrangement for absorbing the relative movement
between components of a boiler that includes loop seal connecting duct and combustor
connecting duct.
Figure 2 shows detail ‘A’ of Fig. 1 to show the connecting details between upper
and lower part.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
In addition to that, by referring to Fig.1, in the present invention, the main
source of relative movement is between Loop-seal connecting duct (01) and Combustor
connecting duct (02). Loop-seal connecting duct (01) is the duct supported at higher
elevation above to the position shown in figure-1, expands in three mutually
perpendicular axes from supporting point. Component (03) is the combustor which is
not shown here, that has large downward and lateral movements in three mutually
perpendicular axes, compared to (01). This arrangement can be at any orientation and
need not be vertical alone. Combustor connecting duct (02) is the joining duct to
combustor (03) which is connected between (03) and (05), inclined for better flow-

ability. Slide-I (05) connected with (02) and Slide-II (06) is connected with (01). Now
both side movements are transferred between (05) and (06) respectively and
expansion/compression system is to be fitted between (05) and (06) to absorb the
movement. The expansion joint (14 & 18) and flanges connected with the said joint (14
and 18) are polygonal shape and Slide-I and Slide-II (05, 06) are in circular shape. To
match these different shaped profiles, profile converting matching arrangement is given
(07, 08) at top and bottom. Internally gap is made purposefully between (05) and (06)
to allow the relative movement. Metallic seal (09) is made to float at gap, to block the
material flow to expansion joint. Item number (09) is the metallic seal which prevents
flow of material to expansion joint. But since it is metal, 100 % sealing is not possible.
Through this material will leak and reach expansion joint. To avoid material to reach
item no (09), air connection (13) is given. Even then some material leaks through (09).
To prevent that and for cooling effect compressed air connection (12) is given. Metal to
metal contact (between 09 and 16) is not practically possible without clearance. To
avoid escaping of material from clearance, flexible seal (11) is provided. Fixing
arrangement (10) is provided to align (05) and (06) as per design requirement.
Compressed air connection (12) is given to pressurise the chamber and to provide
cooling effect. Another compressed air connection (13) is given to prevent the material
to reach metallic seal. Polygonal shaped expansion joint at top and bottom (14 and 18)
is absorbing relative movement. Floating duct with stiffener (15) is given to transfer

lateral movement of system to axial movement of expansion joint. Connecting Rod (16)
is for guiding the movement of top and bottom bellow. Drain (17) is given to remove
the material accumulated in the space between Slide-I (05), stiffener (15), expansion
joints (14, 18) and matching arrangement (08).

WE CLAIM
1. An arrangement for absorbing relative movement between components amidst
dusty and radiant heat environment of a circulating fluidised bed combustion boiler, the
said arrangement comprising;
Slide-I (05) disposed for joining with combustor connecting duct (02) connected
to a combustor (03) having large downward and lateral movements in three mutually
perpendicular axes;
Slide-II (06) disposed for joining with loop seal connecting duct (01) configured
at higher elevation having expansion in three mutually perpendicular axes from
supporting point;
expansion joint (14, 18) and flanges connected to said joint disposed in the said
arrangement;
metallic seal (09) configured to float at gap existing between the said two slides
(05, 06);
flexible seal (11);
matching arrangement (07, 08);
stiffener (15);
compressed air connections (12 and 13);

characterized in that,
the expansion joint (14) is connected to the Slide-I (06) by means of the
arrangement (07) and the expansion joint (18) is connected to the Slide-II (05) by
means of arrangement (08) for absorbing relative movement of components of the
boiler wherein a floating duct with stiffener (15) is disposed to transfer lateral
movement of system to axial movement of expansion joints (14, 18) wherein metallic
seal (09) is configured in the arrangement to prevent flow of hot material to reach
expansion joints (14, 18) when a compressed air connection (13) is disposed to prevent
any leakage of hot material to reach metallic seal (09) and another compressed air
connection is disposed to provide cooling effect, wherein a connecting rod guides the
movement of top and bottom bellow when a drain (17) is configured to remove the
material accumulating in the space between Slide-I (05), stiffener (15), expansion joints
(14, 18) and matching arrangement (08).