FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
An improved noise control device in motors.
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Mishra Neetendra of Crompton Greaves Ltd , Machine (M7) Division, D-5, Industrial Area, MPAKVN, Mandideep - 462046, Madhya Pradesh, India, an Indian National.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.

FIELD OF INVENTION:
The field of this invention relates to motors and associated assemblies.
Particularly, this invention relates to silencer mechanisms for motor.
Still particularly, this invention relates to an improved noise control device in closed air circuit air cooled motor for reducing the noise level and improving heat transfer.
Still particularly, this invention envisages a silencer mechanism for motors.
BACKGROUND OF INVENTION:
Motors are typically, noise producing mechanical assemblies. The rpm of the motor, the power produced by the motor, and such parameters directly affect the noise produced by the motor. There is a guided airflow pattern in motors. It is learnt that this airflow pattern is a major cause of noise produced by the motor.
A Silencer is therefore provided in motors to reduce the noise of the motors by appropriately guiding the air, which passes through the motor, at the exit. Soft foam is glued on all the inner surfaces of motors to absorb this noise. In old designs, a baffle was used, which was suspended straight from the top portion of the motor mechanism. This baffle design was not a major contributor in noise reduction. This baffle also reduced the flow rate of air at the exit by producing resistance in the air flow path.

This subsequently resulted in temperature rise, of exhaust air and the motor.
Hence, there is a need for an improved silencer mechanism which overcomes the issues of the prior art.
OBJECTS OF INVENTION:
An object of the invention is to provide an improved noise control device (silencer mechanism) in closed air circuit air cooled motor for reducing the noise level and temperature rise in the motors.
Another object of the invention is to provide an improved noise control device (silencer mechanism) in closed air circuit air cooled motor which is environment friendly and saves energy losses during air movement.
Another object of the invention is to provide an improved noise control device in closed air circuit air cooled motor which noise control device (silencer mechanism) having low maintenance.
Another object of the invention is to provide an improved noise control device in closed air circuit air cooled motor which noise control device (silencer mechanism) having new aerodynamic baffle to control noise.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a silencer mechanism adapted to dampen noise from an adjunct motor adapted to emit exhaust air, said silencer mechanism comprises:

a. housing comprising an operative back wall adapted to receive
exhaust air from said motor, and an operative front wall adapted to
emit received exhaust air from said housing, characterized in that,
said front wall having a wire mesh grill; and
b. baffle means interposed between said operative back wall and said
operative front wall, said baffle means hanging from an operative
top wall of said housing, characterized in that, said baffle means
being aerodynamically designed with curved walls for damping
noise of air flow by decreasing resistance to air flow and providing
larger surface area for damping.
Typically, said baffle means is covered with damping material.
Particularly, said baffle means is covered with foam.
Typically, said housing is internally coated with damping material.
Particularly, said housing is internally coated with foam.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a front view of the silencer mechanism in accordance with the prior art wherein said silencer mechanism is coupled with a heat exchanger and motor assembly. Figure 2 illustrates a side view of the silencer mechanism in accordance with the prior art. Figure 3 illustrates a further side view of the silencer mechanism in accordance with the prior art. Figure 4 illustrates a bottom view of the silencer mechanism in accordance with the prior art. Figure 5 illustrates an auxiliary view of the silencer mechanism in accordance with the prior art.

The invention will now be described in relation to the accompanying
drawings, in which:
Figure 6 illustrates an auxiliary view of the silencer mechanism;
Figure 7 illustrates a side view of the silencer mechanism;
Figure 8 illustrates a further side view of the silencer mechanism;
Figure 9 illustrates a bottom view of the silencer mechanism; and
Figure 10 illustrates a schematic view of the silencer mechanism coupled with heat exchanger, motor, and fan housing.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a front view of the silencer mechanism in accordance with the prior art wherein said silencer mechanism is coupled with a heat exchanger and motor assembly. Figure 2 illustrates a side view of the silencer mechanism in accordance with the prior art. Figure 3 illustrates a further side view of the silencer mechanism in accordance with the prior art. Figure 4 illustrates a bottom view of the silencer mechanism in accordance with the prior art. Figure 5 illustrates an auxiliary view of the silencer mechanism in accordance with the prior art.
A motor is used in conjunction with a silencer mechanism (100) for the purposes of damping the sound caused by the motor (110). Typically, the sound is a characteristic of the air flow path and the resistance that it

meets in while it passes through the motor and subsequently through the silencer mechanism. Typically, the silencer mechanism comprises a housing with an operative back side (120) which receives air from the coupled motor or heat exchanger (130). Further, the silencer mechanism housing includes an operative front side (140) which permits exit of air. A baffle (150) is introduced between said front side and said back side. This baffle is suspended from the top surface (160) of the housing within the enclosure of said housing, and does not touch the bottom surface (170). The housing is covered on the sides by side walls (180). This baffle acts as an interrupter to the air flow and as a damping mechanism for sound, thus aiding the function of the silencer. The heat exchanger and motor further include a fan cover (185), a fan (190) and an air inlet means (195).
According to this invention, there is provided a silencer mechanism with improved noise control characteristics. The silencer mechanism is adapted for use in conjunction with a motor, typically with a closed air circuit air cooled motor.
Figure 6 illustrates an auxiliary view of the silencer mechanism in accordance with this invention. Figure 7 illustrates a side view of the silencer mechanism in accordance with this invention. Figure 8 illustrates a further side view of the silencer mechanism in accordance with this invention. Figure 9 illustrates a bottom view of the silencer mechanism in accordance with this invention. Figure 10 illustrates a schematic view of the silencer mechanism coupled with heat exchanger, motor, and fan housing.

In accordance with an embodiment of this invention, there is provided a silencer mechanism (200) which comprises a housing having an operative front side (210) and an operative back side (220). Typically, the housing is a box-type housing.
Typically, said silencer mechanism is a device which is used to dampen the noise in high speed motors. Basic function of the silencer is to increase the air traversal path of external air.
In accordance with another embodiment of this invention, there is provided a completely open operative back side of the silencer mechanism for receiving air from the motor assembly (230) associated with said silencer mechanism.
Typically, the silencer mechanism is mounted on heat exchanger (240) on the side of which fan cover (250) is mounted on fan (260). Further, the silencer mechanism housing comprises top, bottom and side walls which define its boundaries.
In accordance with yet another embodiment of this invention, there is provided a wire-meshed operative front face of said silencer mechanism through which air from the motor and silencer exits.
In accordance with still another embodiment of this invention, there is provided an aerodynamic baffle (270) adapted to be suspended from said top side (280) of said housing. The baffle does not touch the bottom side (290). Said aerodynamic baffle typically includes curved front and back surfaces so as to guide the air smoothly out of the silencer mechanism. This improved guidance provides least resistance to air flow (thus,

increasing air flow) and hence, damps the noise during air exit from the motor and heat exchanger assemblies. Dotted arrow lines depict the aerodynamic flow of air guided by the aerodynamic baffle means, in the path of least resistance.
The shape of the baffle leads to increase in surface area thus increasing the length of path of air travel. The shape of the baffle eliminated abrupt changes in direction of air flow. It therefore reduces noise level and also eliminates temperature rise in motor, as more throughput of exhaust air can be achieved due to guided non-abrupt exit. Thus, the silencer makes the motor eco-friendly. Lesser resistance in air flow saves losses during air movement, thus reducing maintenance costs.
In accordance with an additional embodiment of this invention, said aerodynamic baffle has an increased area due to said aerodynamic shape.
In accordance with yet an additional embodiment of this invention, there is provided a foam coating or a foam layer on said aerodynamically shaped baffle. This contributes in further reduction of noise, as it damps the impact of the air from the motor / heat exchanger on to said baffle.
In accordance with still an additional embodiment of this invention, there is provided a foam coating or a foam layer on the inner surfaces of the silencer mechanism to absorb the noise level. Along with absorbing the noise, it also provides for smooth flow for external air exit, thus containing temperature rise of the motor.

We claim,
1. A silencer mechanism adapted to dampen noise from an adjunct motor adapted to emit exhaust air, said silencer mechanism comprising:
a. housing comprising an operative back wall adapted to receive
exhaust air from said motor, and an operative front wall adapted to
emit received exhaust air from said housing, characterized in that,
said front wall having a wire mesh grill; and
b. baffle means interposed between said operative back wall and said
operative front wall, said baffle means hanging from an operative
top wall of said housing, characterized in that, said baffle means
being aerodynamically designed with curved walls for damping
noise of air flow by decreasing resistance to air flow and providing
larger surface area for damping.
2. A claim as claimed in claim 1 wherein, said baffle means is covered with damping material.
3. A claim as claimed in claim 1 wherein, said baffle means is covered with foam.
4. A claim as claimed in claim 1 wherein, said housing is internally coated with damping material.

5. A claim as claimed in claim 1 wherein, said housing is internally coated with foam.