FORM-2
THE PATENT ACT,1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
(As Amended)
PROVISIONAL SPECIFICATION (See section 10;rule 13)
"A SYSTEM TO REGULATE THE FLUE GAS EXIT VELOCITY FROM CHIMNEYS"

A SYSTEM TO REGULATE THE FLUE GAS EXIT VELOCITY FROM CHIMNEYS
TECHNICAL FIELD
The present subject matter generally relates to a system to regulate flue gas exit velocity from chimneys, and more particularly, relates to a system which can regulate velocity of flue gas flow through the chimney.
BACKGROUND
Any combustion produces hot flue gases. In case of boilers or process fired heaters, heat is recovered from the flue gases and then, they are to be released to ambient at minimum specific height, at certain minimum velocity. This process of discharging flue gas at a certain height is achieved by using a chimney where the flue gas enters at the bottom (slightly above ground level) of chimney and exit at the top end. During plant operation, flue gas flow that enters the chimney varies. This results in varying flue gas exit velocity from chimney. As the chimney flues are designed for maximum flue gas flow, the flue gas exit velocity reduces in case the gas flow entering chimney is less than the designed value. Substantial reduction in flue gas exit velocity is very often experienced during boiler part load operations. Such substantial reduction in flue gas exit velocity is not desirable from the point of environmental pollution consideration. This invention devised a system by which chimney flue gas exit velocity can be regulated in relation with flue gas flow through chimney so that flue gas exit velocity can be maintained at a desired level irrespective of plant operating conditions. Possible applications of invention but not limited to are
a) Chimney for boilers (fired and unfired) in thermal power plants.
b) Chimney for boilers in Industrial plants, process industries etc.
Burning of fuels in the power plants, process industries etc. produces hot gases which is discharged to atmosphere at a certain height through chimney. Although it is desirable to maintain constant flue gas velocity at the chimney exit, varying operating conditions generates varying flue gas quantity and that makes it impossible to maintain the constant flus gas exit velocity as the chimney exit area is fixed. Hence, industry

TECHNICAL FIELD
The present subject matter generally relates to a system to regulate flue gas exit velocity from chimneys, and more particularly, relates to a system which can regulate velocity of flue gas flow through the chimney.
BACKGROUND
Any combustion produces hot flue gases. In case of boilers or process fired heaters, heat is recovered from the flue gases and then, they are to be released to ambient at minimum specific height, at certain minimum velocity. This process of discharging flue gas at a certain height is achieved by using a chimney where the flue gas enters at the bottom (slightly above ground level) of chimney and exit at the top end. During plant operation, flue gas flow that enters the chimney varies. This results in varying flue gas exit velocity from chimney. As the chimney flues are designed for maximum flue gas flow, the flue gas exit velocity reduces in case the gas flow entering chimney is less than the designed value. Substantial reduction in flue gas exit velocity is very often experienced during boiler part load operations. Such substantial reduction in flue gas exit velocity is not desirable from the point of environmental pollution consideration. This invention devised a system by which chimney flue gas exit velocity can be regulated in relation with flue gas flow through chimney so that flue gas exit velocity can be maintained at a desired level irrespective of plant operating conditions. Possible applications of invention but not limited to are
a) Chimney for boilers (fired and unfired) in thermal power plants.
b) Chimney for boilers in Industrial plants, process industries etc.
Burning of fuels in the power plants, process industries etc. produces hot gases which is discharged to atmosphere at a certain height through chimney. Although it is desirable to maintain constant flue gas velocity at the chimney exit, varying operating conditions generates varying flue gas quantity and that makes it impossible to maintain the constant flus gas exit velocity as the chimney exit area is fixed. Hence, industry practice is to maintain exit flue gas velocity within an acceptable range to ensure proper flue gas dispersion to atmosphere. In case of single boiler with single chimney (Refer

Figure-1A), exit area of chimney is arrived based on design flue gas quantity and desired flue gas exit velocity.
However, generally power plants and process industries use multiple boilers to run their plants and each boiler may have stand-alone chimney or single chimney connected with multiple boilers housing either a single flue or multiple flues. In case of multiple boilers it is economically advantageous particularly for tall chimneys to provide single chimney housing multiple flues, each flue connected with a single boiler instead of individual chimney for each boiler (Refer to Figure1-B).
The flue gases from multiple boilers could potentially be handled in a single flue, which can lead to further cost savings. However, disadvantage of such arrangement is that, in case any or some of the boilers out of operation or operate at less capacity than design, exit velocity drops drastically and goes below the acceptable range. To minimize the effect of drastic reduction of gas exit velocity the general industry practice is to have multiple flues (within single chimney), each flue connected to one boiler to maintain the flue gas exit velocity within the acceptable range irrespective of other boilers operation/ outage.
General industry practice as described before does not adequately address the issue of maintaining exit flue gas velocity under part load operating conditions of connected boilers in case a single flue chimney is used. Multi-flue chimney eliminates the disadvantage of single flue chimney to a certain extent but is costlier compared to single flue chimney.
Present invention addresses both the above mentioned short comings of single flue and multiple flues chimneys as follows
i. Present invention has the system to regulate the chimney flue gas exit velocity
under varying boiler load conditions.
ii. Present invention eliminates the need for multiple flues; instead a single flue
chimney with velocity regulating system that can be adopted for multiple boilers, leading to cost efficient design.

The said system can also help in regulating the flue gas exit velocity even for a single boiler where significant variations are expected in the flue gas volumes over the operating envelope.
Present invention of flue gas exit velocity regulating system can be adopted for all type of chimneys i.e. RCC, Steel or of any other material with or without internal lining.
SUMMARY
An objective of the present subject matter is to regulate exit velocity of flue gas at the top end of chimney under variable gas volume discharge.
An objective of the present subject matter is to use the present invention to different chimney / flue material.
An objective of the present subject matter is to optimize the cost of construction of chimney.
Yet an objective of the present subject matter is to provide a system to regulate the flue gas exit velocity at location where the system is not exposed to direct wind loads near top end of chimney.
Yet another objective of the present subject matter is to provide a shape to exit area which is nearly equal to circular shape with provision to regulate the flue gas exit velocity as per the gas discharge requirement.
Yet another objective of the present subject matter is to provide a system which causes least disturbance to gas flow and no stagnation of flue gas.
Yet another objective of the present subject matter is to provide a supporting platform at the top end of chimney to mount the system and to provide access to reach the same for maintenance.
Yet another objective of the present subject matter is to provide suitable material of construction for the system to withstand the corrosion effects of flue gas and atmosphere.
Yet another objective of the present subject matter is to provide a system which is simple, reliable, cost effective and also easy for operation and maintenance.

Yet another objective of the present subject matter is to provide a instrumentation system to monitor the position of the shutters from control room.
BRIEF DESCRIPTION OF DRAWINGS
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like components throughout the drawings, wherein:
Figures 1 A and 1B illustrate systems existing in prior art.
Figure 2A illustrates a top view of the gas exit velocity regulating system-1 in accordance with an embodiment of the present subject matter.
Figure 2B illustrates a sectional view of the gas exit velocity regulating system-1 in accordance with an embodiment of the present subject matter.
Figure 2C illustrates an isometric view of all shutters of system-1 in accordance with an embodiment of the present subject matter.
Figure 2D illustrates the isometric view of one shutter of system-1 in accordance with an embodiment of the present subject matter.
Figure 3A illustrates a top view of the gas exit regulating system-2 in accordance with an embodiment of the present subject matter.
Figures 3B illustrates a elevational view of the gas exit velocity regulating system-2 in accordance with an embodiment of the present subject matter.
Figure 3C illustrates a sectional view of the gas exit velocity regulating system-2 in accordance with an embodiment of the present subject matter.
Figure 4A illustrates a top view of the gas exit velocity regulating system-3 in accordance with an embodiment of the present subject matter.
Figure 4B illustrates a elevation view of the gas exit velocity regulating Sustem-3 in accordance with an embodiment of the present subject matter.

Figure 4C illustrates a sectional view of the gas exit velocity regulating System-3 in accordance with an embodiment of the present subject matter.
Figures 5A illustrates a top view of the gas exit velocity regulating system-4 in accordance with an embodiment of the present subject matter.
Figures 5B illustrates a elevation view of the gas exit velocity regulating system-4 in accordance with an embodiment of the present subject matter.
Figures 5C illustrates a sectional view of the gas exit velocity regulating system-4 in accordance with an embodiment of the present subject matter.
Figures 6A and 6B illustrate pulley drive arrangement in accordance with an embodiment of the present subject matter.
Figures 7A and 7B illustrate hydraulic jack arrangement in accordance with an embodiment of the present subject matter.
Figures 8A and 8B illustrate spindle jack arrangement in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
The embodiments of the present subject matter are described in detail with reference to the accompanying drawings. However, the present subject matter is not limited to these embodiments which are only provided to explain more clearly the present subject matter to the ordinarily skilled in the art of the present disclosure. In the accompanying drawings, like reference numerals are used to indicate like components.
The present subject matter includes four embodiments of the system capable to regulate flue gas exit velocity.
System 1:- Segmental pyramid shape or any other suitable
arrangement with shutter plates placed in inclined position to horizontal plane, mounted on supporting frame with hinges. Shutter plates move over hinges

vertically from one inclined position to another inclined
position.
System 2:- Horizontal radial plates move on wheels.
System 3:- Segmental shutter plates move vertically over hinges.
Movement is top to horizontal.
System 4:- Segmental shutter plates move vertically over hinges.
Movement is bottom to horizontal. System 1
The First embodiment of present invention relates to an installation of gas exit velocity regulating system-1(100) on top of a chimney shell (109) of a single flue chimney.
Present invention discloses a system-1 (100) comprising Segmental octagon pyramid shape or equivalent shape arrangement with Shutter plates (101) placed in inclined position to horizontal plane and mounted on supporting frame (107) with hinges. The shutter plates (101) are made of metal or any other suitable material. As indicated in FIG 2A and 2B multiple shutter plates (101) of trapezoidal shape are mounted on a roof slab/ platform (109) at top of surface of chimney. Gas exit velocities required under different boiler operating conditions or part load operating condition of boiler is achieved by movement of shutter plates (101) over hinges vertically from a first position to a second position wherein the first position (100A) is inclined position and secondi position (100B) is another inclined position wherein movement of shutter plates (101) regulate the gas exit velocity.
As shown in FIG. 2A depicts position of one embodiment of the present subject matter, a base frame (107), mounted on top of the platform (109). Frame members are placed in octagon or in different configuration within the scope of present invention as would be obvious to a person skilled in the art. The shutter plates (101) are fabricated and placed to have similar or different configurations within the scope of present invention as would be obvious to a person skilled in the art.
Moreover, FIG. 2B depicts position of frame (117) mounted on a wall of the chimney shell (118) having a frame (117) attached thereto.. A plurality of manholes (113) with cover door is provided to access the roof platform (109) from an operating platform

(108). A frame with sheet cladding (110) is mounted on the roof platform (109) to prevent the gas leakage through the gap between the two adjacent shutter plates (101).
The position of shutter plates (101) in elevation is shown in Fig 2B. Said shutters plates (101) are designed such a way that it introduces minimum head loss, does not need any fans and associate power consumption so that the design facilitates streamlined flow.
The shutters (101) are being actuated by an actuation means so that the shutter plates (101) are moved from the first position to the second position. The actuation means (115) comprising frame (117) attached to a wall of a chimney shell (118) having a at least one pulley (103) rotatably attached thereto.
A rope (104) passes through at least one pulley (103) and connects a fixed counter weight (102) which is attached to the shutter plate (101) at one end and a variable counter weight (105) at other end. The variable counter weight (105) is provided with the removable weights, said variable counter weight (105) is disposed on the operating platform (108) having a guided channels which allow the variable counter weight (105) slide there through. The operating platform is mounted in the proximity of the top surface of the chimney.
Each shutter plate (101) is provided with one set of pulleys (103) and frame (117) attached to chimney wall (118).
An arrester (106) is provided for each shutter plate (101) and mounted on top of the roof platform (109).
Each shutter plate (101) is provided with tie members (111) and bracings (112) connecting the shutter plate with fixed counter weight (102).
A fixed counter weight (102) is provided with a stopper arm (114) being connected to fixed counter weight frame (102). The stopper arm (114) and the fixed counter weight frame (102) are provided with sensors remotely connected with control room to monitor the positions of the shutter plate (101).

Moreover, FIG. 2B indicates position of the frame (117) with at least one pulley (103) wherein, said frame (117) is attached to wall of chimney shell (118). Each shutter (101) is provided with at least one actuating means (115) comprising of one set of frame (117) with at least one pulley (103), rope (104) and variable counter weight (105). The shutter plates, stopper arm, fixed counter weight frame, pulley, sheet cladding, variable counter weight, bracings, tie members bolts and embedded plates are made-up of metal or suitable material.
Fig.2C illustrates the isometric view of all shutter plate (101) in place with fixed counter weights (102) in accordance with an embodiment of the present subject matter.
Fig. 2D shows one shutter plate (101) of the system-1 (100) in accordance with an embodiment of present subject matter.
System 2
The second embodiment of present invention relates to an installation of gas exit velocity regulating system-2(200) on top of a chimney shell (206) of a single flue chimney.
A plurality of closure plates or shutter plates (204) is arranged as shown in Fig.3A, wherein said closure plates (204) are made of metal or any other suitable material and arranged in polygon and formed out of a segment of annular plates. The closure plates (204) are attached with 4 number (two wheels in each set) of wheels/ rollers (217) as shown in FIG. 3B and FIG. 3C using metal frame connected to closure plates (204). The closure plates (204) are fabricated and placed to have similar or different configurations within the scope of present invention as would be obvious to a person skilled in the art.
Moreover, the closure plates (204) are attached to roller support member (203), whereas rollers (217) will roll on top surface of bottom flange of the support member (203). The roller support member (203) is supported by a beam member (202). The beam member (202) is supported by a vertical support (201) which is mounted and fixed on the top of a chimney shell (206).

A plurality of manholes (207) having cover door are positioned within the enlarged chimney shell (206) as indicated in FIG 3A.
The shutter plates (204) are moved from a first position (200A) to a second position (200B) in a horizontal plane upon actuation by an actuating means wherein the first position (200A) allows 100% flue gas flow condition and the second position (200B) allows partial flue gas flow condition. The actuation means comprising a hydraulic jack system (208) which is operatively connected to closure plate (204) to actuate thereof so that the closure plate (204) is moved from the first position (200A) to the second position (200B) in order to regulate the gas exit velocity.
The hydraulic jack system (208) mounted on top platform (205) and is provided with instrumentation system to control /operate the jack remotely.
FIG 3C illustrates a sectional view of the gas exit velocity regulating system (200) depicting positions of a plurality of vertical supports (201), the support beam (202), the roller support members (203), the closure plates (204), the top platform(205), top of the chimney shell (206) and the hydraulic jack system (208).
All elements provided in the system-2 (200) are made of metal or any other suitable material.
System 3
The third embodiment of the present subject matter relates to an installation of gas exit velocity regulating system-3(300) on top of a chimney shell (305) of a single flue chimney.
FIG.4A illustrates a top view of the gas exit velocity regulating system-3 (300) depicting placement of the system in plan on top of the chimney shell (305).
A plurality of shutter plates (302) are attached to a supporting beam (301) with a set of hinges (303), whereas the supporting beam (301) is attached to the chimney shell (305). The shutter plates (302) are made of metal or any other suitable material and

arranged in polygon and formed out of a segment of annular plates. The shutter plates (302) are placed to have similar or different configurations as would be obvious to a person skilled in the art.
The plurality of shutter plates (302) are moved from a first position (300A) to a second position (300B) upon actuation by an actuating means wherein the first position (300A) allows 100% flue gas flow condition and the second position allows partial flue gas flow condition. The actuation means comprising a hydraulic jack system (304) which is operatively connected to the shutter plates (302) and mounted on the top platform (306) in order to enable movement of the shutter plates (302) to regulate the gas exit velocity. The hydraulic jack system (304) is provided with instrumentation system to control /operate the jack remotely. Top of platform (306) is provided with two manholes (307) with cover door, positioned within the enlarged chimney shell (305), as indicated in Figure 4A.
FIG. 4B illustrates a view of the gas exit velocity regulating System-3 (300) depicting position of the beam(301), the shutter plates (302), a plurality of hinges (303), the hydraulic jack system (304), the top platform (306) and the chimney shell (306) in elevation.
FIG 4C illustrates the plurality of shutter plates ( 302) disposed on the top flange of the beam (301) and adapted to rotate over the hinges (303), said hinges (303) are disposed on the top surface of the beam (301) so that the shutter plates (302) rotates from a first position (300A) in a horizontal plane to a second position (300B) in vertical plane upon actuation by the actuation means.
System 4
The fourth embodiment of the present subject matter relates to an installation of gas exit velocity regulating system-4(400) on top of chimney shell (405) of a single flue chimney.

As indicated in FIG 5A position of shutter plates (402) are located within the enlarged chimney shell (405) and said shutter plates (402) are made of metal or any other suitable material and arranged in polygon and formed out of a segment of annular plates. Shutter plates (402) are fabricated and placed to have similar or different configurations within the scope of present invention as would be obvious to a person skilled in the art.
A plurality of supporting beam members (401) are attached to the shutter plates (402) by a set of hinges (403). The supporting beam (401) is made-up of metal material or any other suitable material, is attached to chimney shell (405).
A plurality of manholes (407) having cover door are positioned within the enlarged chimney shell (405) on the platform (406).
FIG. 5B illustrates a view of the gas exit velocity regulating system-4(400) depicting position of beam (401), shutter plates (402) position, hinge(403), hydraulic jack system(404), top platform(406) and chimney shell (405) in elevation.
The plurality of shutter plates (402) are moved from a first position (400A) to a second position (400B) upon actuation by an actuating means wherein the first position (400A) allows 100% flue gas flow condition and the second position allows partial flue gas flow condition. The actuation means comprising a hydraulic jack system (404) which is operatively connected to the shutter plates (402) and mounted on top platform (406) in order to enable movement of the shutter plates (402) so that the gas exit velocity can be regulated. The hydraulic jack system (404) is provided with instrumentation system to control /operate the jack remotely.
FIG. 5C illustrates the plurality of shutter plates ( 402) disposed on the top flange of the beam (401) and adapted to rotate over the hinges (403), said hinges (403) are disposed on the top surface of the beam (401) so that the shutter plates (402) rotates from a first position (400A) in a vertical plane to a second position (400A) in a horizontal plane upon actuation by the actuation means.

For the operation of systems disclosed in the embodiments above, an operating system is necessary. The operating systems below and any combination or derivation from these three can also be adopted
a) a pulley drive arrangement employing gravitational force with dead weights,
b) a hydraulic drive (hydraulic jack) arrangement,
c) a spindle jack drive arrangement.
For operation of the system -1 disclosed in the first embodiment of the present invention, all the three operating mechanisms are considered. For the systems 2, 3 & 4 disclosed in the second, third and fourth embodiment of the present invention the hydraulic drive or spindle drive arrangement is considered.
FIG 6A and 6B indicate the pulley drive engagement consisting of pulley, rope and variable weights moving in a guided frame which is mounted on a platform of chimney called operating platform. Shutter movement is regulated by addition or removal of weights. FIG 6A shows that the position of the shutter for 100% of the flow of flue gas whereas FIG 6B shows that the position of the shutter for partial flow of flue gas.
FIG 7A and 7B illustrate the hydraulic jack mounted on platform of chimney. One end of jack rod is connected to permanent counter weight attached to shutter. Rotation of shutters is achieved by operating the hydraulic jack. FIG 7A shows that the position of the shutter is 100% of the flow of flue gas whereas FIG 7B shows that the position of the shutter for partial flow of flue gas.
FIG 8A and 8B illustrate the spindle drive arrangement which is mounted on platform of chimney. One end of spindle rod is connected to permanent counter weight attached to shutter. Rotation of shutters is achieved by movement of the spindle rod. FIG 8A shows that the position of the shutter is 100% of the flow of flue gas whereas FIG 8B shows that the position of the shutter for partial flow of flue gas.

We claim:
1. A system to regulate flue gas exit velocity, the system comprising:
- a chimney having a chimney shell (118, 206, 305, 405);
- a roof platform (109, 205, 306, 406) disposed on a top surface of the chimney shell (118, 206, 305, 405); and
- a plurality of shutter plates (101, 204 ,302 ,402) operatively attached to the roof platform (109, 205, 306, 406) wherein gas exit velocity is regulated by movement of the plurality of shutter plates (101, 201 ,302 ,402) from a first position (100A, 200A, 300A, 400A) to a second position (100B, 200B, 300B, 400B), the movement of the plurality of shutter plates (101, 201, 302 ,402) is actuated by at least one actuating means (115, 208, 304, 404).
2. The system to regulate flue gas exit velocity as claimed in claim 1, wherein the each of the shutter plates (101) is rotatably connected by hinges to a base frame (107), the base frame (107) being mounted on the platform (109).
3. The system to regulate the flue gas exit velocity as claimed in claim 1 and 2, wherein each shutter plate (101) is provided with fixed counter weight (102) attached with stopper arm (114); said counter weight (102) is a safe measure to shutter position at 100% gas flow condition.
4. The system to regulate flue gas exit velocity as claimed in claim 1, wherein each of the shutter plates (101) is provided with ties (111) and bracing (112) to make the shutter plate (101) more rigid to sustain the dynamic loads.
5. The system to regulate flue gas exit velocity as claimed in claim 1, wherein the each of the shutter plates (101) is positioned in vertical plane at an inclination to horizontal.
6. The system to regulate the flue gas exit velocity as claimed in claim 1 and 2, wherein the actuation means (115) comprising at least one pulley assembly (103) configured to be operatively connected to at least one shutter plate (101); said actuation

means (115) is configured to rotate at least one of shutter (101) from a first position (100A) to a second position (100B).
7. The system to regulate the flue gas exit velocity as claimed in claim 6, wherein
the pulley assembly (115) comprising
a frame (117) mounted on a wall of the chimney shell (118);
at least one pulley (103) rotatably connected to the frame (117); and
a rope (104) passing through at least one pulley (103); said rope (104) connecting at least one fixed counter weight (102) attached to the shutter (101) and at least one counter weight (105) disposed on an operating platform (108); said operating platform (108) is mounted on the chimney in proximity of edge of the top surface of the chimney shell (118).
8. The system to regulate the flue gas exit velocity as claimed in claim 1 to 2, wherein at least one arrester (106) being disposed on the top surface of the roof platform (107); said arrester (106) is configured to restrict movement of each of the plurality of shutter plates (101).
9. The system to regulate the flue gas exit velocity as claimed in 1 to 2, wherein at least one frame with sheet cladding (110) being disposed on the top of platform (107); said frame with sheet cladding (110) is configured to restrict the gas leakage through the gap between two adjacent shutter plates (101).
10. The system to regulate the flue gas exit velocity as claimed in claim 1 and 2, wherein the plurality of shutter plates (101) is configured to be arranged on the frame (107) in a polygon configuration.
11. The system to regulate the flue gas exit velocity as claimed in claim 1, wherein at
least one shutter plate (204) disposed on top surface of the chimney shell (206)
configured to be operatively connected to at least one roller (217) configured to enable
movement of at least one shutter plate (204) from a first position (200A) to a second
position (200B) in horizontal plane.

12. The system to regulate the flue gas exit velocity as claimed in claim 11, wherein the roller (217) moves on a bottom flange of a roller beam (203); said roller beam (203) being supported by a support beam (202) in horizontal direction and by a vertical support (201) in vertical direction.
13. The system to regulate the flue gas exit velocity as claimed in claim 11, wherein the shutter plate (204) is actuated by the actuation means ( 208) configured to be operatively connected to the shutter plate (204); said actuation means (208) comprising a hydraulic jack system (208) being mounted on the roof platform (205).
14. The system to regulate the flue gas exit velocity as claimed in claim 1, wherein at
least one shutter plate (302) is disposed on the top surface of a beam (301) comprising at
least one hinge (303); said at least one shutter plate (302) is configured to rotate over at
least one hinge (303) from a first position (300A) in vertical plane to a second position
(300B) in horizontal plane.
15. The system to regulate the flue gas exit velocity as claimed in claim 1, wherein at least one shutter plate (402) is disposed on the top surface of a beam (401) comprising at least one hinge (403); said at least one shutter plate (402) is configured to rotate over at least one hinge (403) from a first position (400A) in horizontal plane to a second position (400B) in vertical plane.
16. The system to regulate the flue gas exit velocity as claimed in claim 14 and 15, wherein the shutter plates (303, 402) are configured to rotate from the first position (300A, 400A) to the second position (300B, 400B) by the actuation means comprising a hydraulic jack system (304, 404); said hydraulic jack system (304, 404 ) is configured to be operatively connected to at least one shutter plate (303, 402).
17. The system to regulate the flue gas exit velocity as claimed in claim 16, wherein said hydraulic jack system (304, 404) is mounted on the roof platform (306, 405).
18. The system to regulate the flue gas exit velocity as claimed in claim 11 to 16, wherein the plurality of shutter plates (204, 303, 402) are configured to be arranged in polygon and formed out of a segment of annular plates.

19. A system to regulate the flue gas exit velocity as claimed in claim 1, wherein the actuation means (101, 208, 304,404) are provided with an instrumentation system configured to operate the actuation means (208, 304,404) remotely.
20. A system to regulate the flue gas exit velocity as claimed in claim 1, wherein the roof platform (109,205,306, 406) comprising at least two access manholes (113, 207, 307,407) provided for installation of actuation means.