FIELD OF THE INVENTION
The present invention relates to a Winding Robot for automation of angular winding of brush seals used in steam turbines, gas turbines and compressors. The invention in particular relates to a mechanism which facilitates the winding of wire on a flat circular plate at a particular angle, as a part of brush seal manufacturing cycle. More particularly, the invention relates to an apparatus for automation of brush seal winding process with improved bristle pack density.
BACKGROUND OF THE INVENTION
Brush seals are used in various equipments like steam turbines, gas turbines and
compressors to reduce the process fluid leakage and increase the internal
process efficiency. Brush seals are made of a bristle packs sandwiched between
a pair of backing plates. The backing plate is attached to a stationary part and
the bristles extend outwardly toward a rotating part. The free end of the bristles
rubs against the rotating part and prevents fluid leakage. The bristle packs are
an assembly of thin high temp alloy wires. The wires in the assembly are
arranged at an angle ranging from 35° to 45° to the radius, called as cant or lay
angle. Prior art show multiple methods for making a brush seal. Each method
involves multiple process steps, because the thin wires need to be arranged
compactly to avoid leakage through the wires and at an angle to the radial
direction to minimise friction with the rotating part. Thus, the step of such
laying of wires is critical.
For winding of the thin alloy wires, the prior art teach different winding techniques. Some of the winding techniques are described below.

US Patent 4204629 describes a method of manufacture of a brush for use as a seal comprising the steps of winding a filament or filaments of bristle material onto a mandrel which carries on each side thereof a side-plate of the brush so that the bristle material overlies an exposed face of each side-plate at an angle of 45°. After winding, a second side-plate is made to overlie the bristle material to sandwich it between the two plates and the side-plates and bristle material are welded or fused together at one edge thereof. The bristle material is then cut and the plates are removed from the mandrel to produce two brushes with bristles angularly projecting from the other edge at an angle.
US Patent 4732339 discloses an apparatus for winding a filament onto a former which comprises one or more filament supply bobbins mounted on an annular carrier for rotation about a first axis for receiving a plurality of windings of the filament, and a translation device for moving the former relative to the carrier along a path which passes through the carrier thereby enabling the filament to be wrapped around the former. A pair of pinch rollers positioned at the mid span of each bobbin guides the filament onto a loading surface over which the filament passes from the pinch rollers to the former. The loading surface is formed by the radially innermost portion of the carrier and is arcuate in cross section. The apparatus reduces bending of the filament as it is wound onto the former.
US Patent 0214628A1 teaches a method of forming brush seal segments which includes mounting a pair of full formed plates having opposite arcuate edges in back to back relation and wrapping wire about the form plates in multiple passes to form wire runs at angles, e.g., 35 – 45° relative to radii of the arcuate edges. Half form plates are assembled to opposite sides of the full form plates adjacent one edge of the sub assembly. The wire wrap adjacent to the one edge of the

full form plates is removed. Welds are applied between each adjacent of and full form plates. The inner edges of the wrapped wire and inner frame members of the full form plates are removed. The assembly is then separated to form a pair of arcuate brush seal segments.
Indian patent Application No. 461/Kol/2012 discloses a method for manufacturing brush seals for turbomachinery operable at lower radial rotor-stator clearances with improved leakage performance.
Indian patent Application No. 1064/Kol/2012 discloses a manual angular winding tool for manufacture of bristle pack to build brush seals.
The present invention is an apparatus for automation of brush seal winding process with improved bristle pack density.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an apparatus for automation of brush seal winding process with improved bristle pack density.
Another object of the invention is to propose an apparatus for automation of brush seal winding process with improved bristle pack density, wherein the apparatus is a Winding Robot, which is non toroidal winding machine, for semi automation.
A further object of the invention is to propose an apparatus for automation of brush seal winding process with improved bristle pack density wherein the apparatus is a non-toroidal winding machine for semi-automation of angular winding process for manufacturing of bristle packs to build brush seal.

SUMMARY OF THE INVENTION
Accordingly, there is provided An apparatus for automation of brush seal winding process with improved bristle pack density, comprising : a brush seal plate (1) having a plurality of slots (2) including radially projected fins (3); at least one wire-spool (5) with a shaft (20) accommodating wire spool and allowing the bunch of wires to be drawn through a first set of guides and pulley (6,7,8) to a wire tensioner (9); a winding mandrel (10) having one each winding arm (12), a base (18) configured with adjustable slots (19), and a back plate (11) including a nozzle (13), the wires being guided from the mandrel (10) by the winding arm (12) to the nozzle (13) via a second set of pulleys and guides (14, 15, 16 and 17); an electric motor (4) with a belt drive (31) to rotate the winding mandrel (10) which in turn rotating the winding arm (12) about the brush seal plate (1) and causing the wire to be drawn from the spool (5); a plurality of equi-spaced divisions (21) and a single division (22) having lower radius than that of said plurality of equi-spaced divisions (21) are constructed on the winding mandrel back plate (11); an index notch sensor (23), a sector notch sensor (24), a slot detection sensor (34), a first job sensor (30) and a second job sensor (32), wherein indexing of the seal plate (1) achieved through a worm gear (25) including a worm shaft (26) driven by a second electric motor (27), wherein the indexing sensor (23) further detecting the single division (22) and detection of the other divisions (21) by said sector notch sensor (24), wherein the slot detection sensor (34) detecting the radially projected fins (3) for indexing the brush seal plate (1) at the reverse direction when one layer of winding in the slot (2) is completed and allowing continuation of the winding in each slot for plurality number of layers, wherein the second job sensor (32) detecting a pin (28) on a brush seal plate holder (29) to cause the stoppage of rotation of the drive motor (4) and wherein the first job sensor (30) causes the brush seal plate

(1) indexed at home position; and a controller (33) for monitoring the feed back signals from the index notch sensor (23) and the sector notch sensor (24) and controlling the rotational speed of the winding mandrel (10) including setting of the brush seal plate (1) at home position at the beginning of the winding.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.1. Front view of the Winding Robot.
Fig.2. Top view of the Winding Robot showing wire spool holder and wire
tensioner.
Fig.3. Top view of the Winding Robot showing the winding mechanism and
indexing mechanism.
Fig.4. Isometric view of the winding mandrel and associated sensors.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 shows an apparatus in the form of a Winding Robot to wind the wire at an angle (θ) to the radial on a brush seal plate 1. Brush seal plate 1 has slots 2 and radially projected fins 3 at the ends of the slots as shown in Fig. 3. These slots (2) are provided at an angle to the radial so that the wires are perpendicular to the slot edge while winding. The radial projection of the fins 3 on the brush seal plate 1 outer diameter depends on the thickness of the brush seal.
Wire is drawn from a wire spool 5 as a bunch of wires through a pair of ceramic guides 6 & 7 and a ceramic pulley 8 to a Wire Tensioner 9 which provides the required adjustable wire tension.

Wire passes on to the brush seal plate 1 through wire tensioner 9 via a winding mandrel 10, one each winding arm 12 and nozzle 13. Winding arm 12 guides the brush seal wire from the winding mandrel 10 to the tungsten carbide nozzle 13 through a pair of ceramic pulleys and guides 14, 15, 16 and 17. Ceramic pulleys and ceramic guides are used to avoid wear of these pulleys and guides. Winding mandrel base 18 is adjustable in the base plate slots 19 as per the required angle of winding (θ).
Winding mandrel 10 is driven by a motor 4 through a belt drive 31. At the beginning of winding, the first slot 2 of the brush seal plate 1, the wire is knotted to a hole in the brush seal plate (1) and guided through the first slot. Then the winding is started by switching on the winding mandrel drive motor 4. Winding arm 12 is an integral part of the winding mandrel. Motor 4 rotates the winding mandrel 10 which in turn rotates the winding arm 12 about the brush seal plate 1. As the winding arm 12 rotates, the wire is drawn from the wire spools which rotate freely on a wire spool shaft 20 due to wire pull.
Winding mandrel back plate 11 has specific number of equi-spaced divisions 21 at the outer periphery with one division 22 having lesser radius than the radius of the equi-spaced divisions 21. An index notch sensor 23 detects the division 22 and another sector notch sensor 24 detects the divisions 21. A Controller 33 uses the feedback from the index notch sensor 23 and the sector notch sensor 24 to control the speed of the winding mandrel 10 according to the position of the brush seal on the brush seal plate 1. As the brush seal plate 1 is flat and not cylindrical, in shape, the mandrel 10 speed variation is required to avoid slackness in the winding.

One revolution of the mandrel 10 makes one turn of winding on the brush seal plate 1. Now, the brush seal plate 1 needs to be rotated by a required pitch; the pitch is defined by the width of the wire bunch. Indexing of the brush seal plate
1 is achieved through a worm gear 25 and a worm shaft 26. The Worm shaft 26
is driven through a directly coupled worm shaft drive motor 27, whose rotation is
controlled. The indexing resolution in this apparatus is achieved very precisely;
which is of the order of few microns. The required indexing depends on the wire
diameter and number of wires in the bunch.
After completion of one layer of winding in the slot 2, the brush seal plate 1 required to be indexed in the reverse direction. This is achieved through a slot detection sensor 34 detecting the radially projected fin 3 at the ends of the slots
2 on the brush seal plate 1. The direction of the worm shaft drive motor 27 is
reversed thru the controller based on the feed back from the slot detection
sensor 34. Winding is continued in each slot for the pre-defined number of
layers. Then the brush seal plate 1 is indexed for winding of the next slot 2.
A job sensor 32 detects a pin 28 on a brush seal plate holder 29 and this triggers the winding mandrel drive motor 4 to stop.
Beginning of the job sensor 30 detects the pin 28 on the brush seal plate holder (29) and the brush seal plate (1) is indexed to the home position. Home position means positioning of the first slot 2 of the brush seal plate 1 for winding.
The Winding Robot controller 33 sets the brush seal plate 1 at the home position and detects the end of the winding. It also provides the status of the winding such as number of slots, number of layers and number of turns of the winding.

WE CLAIM :
1. An apparatus for automation of brush seal winding process with improved
bristle pack density, comprising :
- a brush seal plate (1) having a plurality of slots (2) including radially
projected fins (3);
- at least one wire-spool (5) with a shaft (20) accommodating wire spool
and allowing the bunch of wires to be drawn through a first set of guides
and pulley (6,7,8) to a wire tensioner (9);
- a winding mandrel (10) having one each winding arm (12), a base (18)
configured with adjustable slots (19), and a back plate (11) including a
nozzle (13), the wires being guided from the mandrel (10) by the winding
arm (12) to the nozzle (13) via a second set of pulleys and guides (14, 15,
16 and 17);
- an electric motor (4) with a belt drive (31) to rotate the winding mandrel (10) which in turn rotating the winding arm (12) about the brush seal plate (1) and causing the wire to be drawn from the spool (5);
- a plurality of equi-spaced divisions (21) and a single division (22) having lower radius than that of said plurality of equi-spaced divisions (21) are constructed on the winding mandrel back plate (11);
- an index notch sensor (23), a sector notch sensor (24), a slot detection sensor (34), a first job sensor (30) and a second job sensor (32), wherein indexing of the seal plate (1) achieved through a worm gear (25) including a worm shaft (26) driven by a second electric motor (27), wherein the indexing sensor (23) further detecting the single division (22) and detection of the other divisions (21) by said sector notch sensor (24), wherein the slot detection sensor (34) detecting the radially projected fins (3) for indexing the brush seal plate (1) at the reverse direction

when one layer of winding in the slot (2) is completed and allowing continuation of the winding in each slot for plurality number of layers, wherein the second job sensor (32) detecting a pin (28) on a brush seal plate holder (29) to cause the stoppage of rotation of the drive motor (4) and wherein the first job sensor (30) causes the brush seal plate (1) indexed at home position; and - a controller (33) for monitoring the feed back signals from the index notch sensor (23) and the sector notch sensor (24) and controlling the rotational speed of the winding mandrel (10) including setting of the brush seal plate (1) at home position at the beginning of the winding.
2. The apparatus as claimed in claim 1, wherein the winding speed is varied according to the instantaneous position of the wire across the width of the brush seal plate to avoid slackness in the winding.
3. The apparatus as claimed in claim 1, wherein the wire is wound on the brush seal plate at an angle 35o to 45o to the radius of the brush seal plate.
4. The apparatus as claimed in claim 1, wherein the brush seal plate is indexed during winding according to width of the wire bunch drawn from the plurality of wire spools.
5. The apparatus as claimed in claim 1, wherein the Index Notch Sensor. Sector Notch Sensor, first Job Sensor, second Job Sensor and the Slot Detection Sensor perform the following :

I. Home positioning of the brush seal plate,
II. Control on number of layers,
III. Indexing of the brush seal plate to next slot after completion of winding for the current slot,
IV. Indexing of the brush seal plate in forward and backward directions to achieve the required number of layers for the slot,
V. Detection of end of the job and triggering the winding process to stop,
VI. Status of the winding process in terms of number of layers, the slot no. in process, no. of turns,
VII. Speed variation of the mandrel.