FIELD OF INVENTION
The present invention relates to dampers and in particular to a multiple Biplane damper to cater to larger duct requirement adaptable to power and industrial boilers.
BACKGROUND OF THE INVENTION
The Biplane dampers (01) as shown in Fig 1, are engaged for power & industrial boilers to cater to flue duct requirement. The Hot air, Cold air and the Flue gas duct sizes are broadly based on Boiler sizes (MW rating) & coal quality. Whenever the duct size becomes larger two numbers of dampers or multiple dampers are-used and assembled one above the other in an axial direction. The overall size of the largest biplane dampers of a typical 600 MW boiler is approximately 11.5 x 5.5 meters.

Transportation of these large size dampers poses problems, since the above size
falls in very high Over dimension consignment (ODC) category.
To overcome the above difficulty a novel method was invented to develop a
multiple biplane dampers in place of two dampers and accommodate these
multiple dampers one over the other in an axial direction. The size of each of the
above dampers, will be reduced as above and will facilitate easier handling &
transportation.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a multiple Biplane damper (02) which are stacked one above the other in an axial direction for a given duct cross section in a thermal power plant to overcome the difficulty of transportation & handling.

Another object of the present invention is to propose a multiple Biplane clamper (02) adaptable to thermal power plants with a provision of providing individual seal air to all Biplane dampers.
Yet, another object of the present invention is to propose a multiple Biplane damper (02) which can be easily manufactured, assembled &. transported to site.
A further object of the present invention is to propose a multiple Biplane damper which can be directly installed in the respective duct at site.
An yet further object of the present invention is to propose a multiple Biplane damper which saves skilled manpower at site.
SUMMARY OF THE INVENTION
The present invention is provided with a multiple biplane damper to cater to large duct requirements adaptable to power and industrial boiler, the multiple biplane

damper comprises a plurality of identical rectangular shaped biplane dampers are assembled one over the other in an axial direction resembling to be a single unit, each biplane damper posses one drive end and one non-drive end, the top damper is connected to seal air piping at the top and the bottom damper is connected to seal air piping at the bottom and the middle damper is connected to seal air piping from a non drive end side by a separate connecting pipe disposed at the middle, a provision to mount flow dividers between each of the above three individual biplane damper.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Fig.1: Schematic drawing of Biplane Damper.
Fig.2: Schematic arrangement of multiple Biplane Damper consisting of
Top Damper (03), Middle Damper (04) & Bottom Damper (05).

Fig.3: Seal Air Piping arrangement for multiple Biplane Damper.
Fig.4: Seal Air Piping arrangement for multiple Biplane Damper.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Accordingly, there is a proposed to construct a multiple Biplane damper (02) to meet higher sized duct requirements. Multiple Biplane damper consists of three numbers of rectangular shaped Biplane damper (01) mounted one over the other in an axial direction. The above three Biplane dampers are coded as a Top Damper (03), a Middle Damper (04) and a Bottom Damper (05). All the above three dampers are independently operated by individual actuators. There is a provision to mount flow dividers between each of the above Biplane dampers. Flow dividers allow unrestricted flow at the intersection of two Biplane dampers.

Two alternative methods has been implemented for providing seal air to the damper placed in the middle. One of the seal air arrangement as shown in fig 3 provides seal air to pass from top (03) and bottom Biplane dampers (05) to middle damper (04). The second seal air arrangement (07) as shown in Fig 4 allows seal air flow from the non drive end of the frame through the jamb seal.
The present invention is described herein with reference to figure-2. The multiple Biplane damper (02) consist of three rectangular shaped Biplane dampers (01) stacked one over the other in an axial direction as shown in Fig 2. The existing system can accommodate only double split Biplane dampers (01), i.e two dampers mounted one over the other. By providing three dampers in place of two dampers the overall size of each damper is relatively smaller thereby enabling easier manufacturing, assembly, handling and transportation.

Seal air is provided to double split dampers by plenum ducts mounted on the top frame (14) and bottom frame (15) of top and bottom dampers respectively. In case of multiple dampers, there is no space available for providing a plenum duct to middle dampers. This design difficulty has been overcome by providing a seal air to middle damper by two design modifications. The first design (06) as shown in Fig. 3, provides seal air through cut outs in the top and bottom frame of middle damper seal air. The above design allows seal air to pass from top and bottom Biplane dampers to middle damper. The second method (07) as shown in Fig. 4, comprises two inverted 'Y' shaped pipes (08, 09) joined at middle damper (04) at non-drive end. The end of small arms of 'Y' shaped pipe (08, 09) are again joined by another inverted 'Y' shaped pipe (12). The ends of the small arms (10, 11) of 'Y' shaped pipe (12) are joined with the main seal Air pipe (13). This is achieved by providing cut out in the Jamb Seal mounted on the non-drive end of middle damper (04). The Biplane damper is stacked one above the other axially to form a multiple biplane damper for a given duct cross-section in a thermal power plant to overcome the difficulties of transportation and handling of two individual large biplane dampers as compared to double split

dampers. There is a provision to mount flow dividers between each individual biplane damper. There is also a provision in the present invention to provide seal air to middle damper by two structural modifications. The first method (06) provides seal air to middle damper from top and bottom dampers through cut out in the top and bottom frame of middle dampers. This method allows seal air to pass from top and bottom biplane dampers to middle damper.
A second method (07) provides seal air flow from non drive end of the frame through the Jamb Seal. This is achieved by providing cut out in the Jamb Seal mounted on the non-drive end of the middle damper. The three individual biplane dampers (02) of the multiple biplane damper is operated by three independent electrical actuators. The multiple biplane damper is operable both in Vertical and Horizontal direction.

WE Claim
1. A multiple biplane damper to cater the larger duct requirements adaptable to power and industrial boiler, the multiple biplane damper comprises:-
- a plurality of identical rectangular shaped biplane dampers assembled one over the other in an axial direction resembling a single unit;
- each biplane damper posses one drive end and one non-drive end;
- a top damper is connected to seal air piping at the top, a bottom damper is connected to seal air piping at the bottom and a middle damper is connected to seal air piping from a non drive end side by •a separate connecting pipe disposed at the middle;
- means for mount is flow dividers between each of the three
individual biplane dampers.

2. The multiple biplane damper as claimed in claim 1 wherein the middle damper comprises means for sealing air flow in two ways.
3. The multiple biplane damper as claimed in claim 3, wherein in the first method seal air is provided to the middle damper from the top and bottom dampers through a cut out formed in the top and bottom frame of the middle damper to seal air provided for middle damper.
4. The multiple biplane damper as claimed in claim 3, wherein the second method provides seal air flow from non-drive end of the frame by a separate connecting means by configurating cut outs in the Seal mounted on the non-drive end of middle damper.
5. The multiple biplane damper as claimed in claim 1, wherein each individual biplane damper is operated by an independent electrical actuator.

6. The multiple biplane damper as claimed in claim 1, wherein it can be mounted vertically or horizontally to meet higher sized duct requirement.
7. The multiple biplane damper to cater the large duct requirement as substantially described and illustrated herein along with accompanying drawing.

ABSTRACT

The present invention is provided with a multiple biplane damper to cater to larger duct requirements adaptable to power and industrial boiler, the multiple biplane damper comprises a plurality of identical rectangular shaped biplane dampers are assembled one over the other in an axial direction resembling to be a single unit, each biplane damper posses one drive end and one non-drive end, the top damper is connected to seal air piping at the top and the bottom damper is connected to seal air piping at the bottom and the middle damper is connected to seal air piping from a non drive end side by a separate connecting pipe disposed at the middle, a provision to mount flow dividers between each of the above three individual biplane damper.