FORM 2
THE PATENTS ACT, 1970
(39 of 1970) As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Silencer mechanisms for heat exchangers.
APPLICANTS:
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worii, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Pawar Sumedh Pundlik, Dhavileswarapu Srinivas, Joshi Kishor Uddhav of Crompton Greaves Ltd, Analytics Centre, CG Global R&D Centre, Kanjur (E), Mumbai 400 042,Maharashtra, India; all Indian Nationals.
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 the Invention:
This invention relates to the field of mechanical assemblies.
Particularly, this invention relates to the field of heat exchangers and motors.
Still particularly, this invention relates to the field of silencer mechanisms for heat exchangers.
Background of the Invention:
A motor typically includes a rotor, a stator and associated assemblies, which assemblies are heat generating assemblies. There is a need to dissipate the heat for long life of the motor and so that the motor works according to specified standard.
There is, hence, provided a heat exchanger mechanism adapted to receive hot air from the motor. A fan is driven to extract relatively cold air from the surrounding atmosphere into the heat exchanger. Guided through the conduits of the fan cover having intermittent baffles, the relatively cold air comes into contact with the hot air from the motor at the tubes, and effective cooling of the ambient air around the motor and in the motor housing is carried out. The previously relatively cold air, records an increase in temperature due to transfer of heat.
This hot air, now, has to be exited through the heat exchanger. During exiting these gases / air, pressure is created which may lead to turbulence and vortex formation due to the rough nature of the exit path. The air flow is not contoured and is abrupt, which leads to misguided exit along with backflow. This leads to increase in

pressure and noise during air exit. Further, it regurgitates on the continuous flow of air that is supposed to be exited, thus, decreasing throughput of air cooling and heat exchange
Figure 1 illustrates a motor with associated heat exchanger and air exhaust assembly with silencer mechanism.
A motor (10) is placed in a motor housing (12). A common shaft drives a plurality of fans (14, 16. 18). Relatively smaller fans (14, 16) guide the air, which is relatively hotter, from the motor housing in the direction of the heat exchange]-(20). Relatively larger fan (18) sucks in ambient air which is relatively cooler. The fan (18) is placed in a fan cover (22). Ambient relatively cooler air is channeled through the fan cover and guided in a dispersed manner through the tubes which form the heat exchanger (24), thereby coming in communication with the relatively colder sucked in ambient air. Heat exchange takes place (as shown by circular arrows), here. The hot air around the motor, in the motor housing, is relatively cooler, now. Figure 1 also shows the external flow circuit assembly for an HT motor. Air enters at one end (19) and is then guided through the fan cover (22) and heat exchanger tubes (24) and exits (31, 33) through the silencer (30). Noise absorbent material is pasted on the entire inner surfaces of silencer which will absorb the air pressure fluctuations and hence reduce the noise levels of the air.
The residual relatively hot air needs to be guided out of the heat exchanger. There is, hence, provided a silencer mechanism which typically includes laterally and / or dorsally-ventrally located air outlets. Preferably, the silencer mechanism may be lined, interiorly, with foam which absorbs air pressure, thereby reducing noise.

The placement of air outlets is such that air, while exiting, creates turbulence due to bouncing off the walls of the interiors of the silencer mechanism. This reduces the mass flow rate of the air exhaust, thereby affecting the throughput of heat exchange, thereby affecting motor performance and motor life.
There is a need to obviate the limitations of the prior art.
Prior Art:
Figure 2 illustrates a schematic silencer mechanism of the prior art.
Figure 3 illustrates another schematic silencer mechanism of the prior art.
Air exits abruptly in both these mechanisms. In the silencer of Figure 2, the air leaving the HE had to take a 90° turn and exit from top and bottom. This adds to the system resistance and reduces the air mass flow rate. This would result in higher temperature rise in motor. In the silencer of Figure 3, the air has to take three 90 degree turn from inlet to outlet. This again increases the system resistance and lead to lower air mass flow rate and higher temperature rise. Even though noise absorbent material is adequately placed in the silencer, the abrupt directions of airflow may cause vortex air currents thereby reducing the throughput of air flow exiting the assembly.

Objects of the Invention;
An object of the invention is to provide optimum mass air flow through and out of a heat exchanger without compromising on motor life or motor working parameters.
Another object of the invention is to provide optimum noise reduction while guiding air out of heat exchanger.
Yet another object of the invention is to efficiently guide air out of said heat exchanger.
Summary of the Invention:
According to this invention, there is provided a silencer mechanism for heat exchangers, said mechanism comprises:
a. air inlet means adapted to allow entry of air from an associated assembly;
b. air outlet means located on walls of said silencer mechanism for providing
exit of said entered air;
characterized in that, said silencer mechanism includes a streamlined guide baffle means adapted to smoothly guide air through said air outlet means.
Typically, said baffle means is a curvilinear baffle means.
Preferably, said baffle means is a wave shaped baffle means with two laterally sloping edges.

Alternatively, said baffle means is a wave shaped baffle means with four circumferentially placed sloping edges.
Typically, said streamlined guide baffle means is a sound absorbent coated streamlined guide baffle means.
Preferably, said streamlined guide baffle means is a foam coated streamlined guide baffle means.
Brief Description of the Accompanying Drawings:
The invention will now be described in relation to the accompanying drawings, in which:
Figures 4 and 5 illustrate a schematic of the silencer mechanism in accordance with this invention.
Detailed Description of the Accompanying Drawings:
According to this invention, there is provided a silencer mechanism for heat exchangers.
Figures 4 and 5 illustrate a schematic of the silencer mechanism (100) in accordance with this invention.

In accordance with an embodiment of this invention, there is provided a streamlined guide baffle means (50) adapted to smoothly guide air through exits provided on edges of said silencer.
In accordance with a preferred embodiment of this invention, there is provided a streamlined guide baffle means with sound absorbent pasted on it. Typically, the sound absorbent is foam.
The air exiting the HE would strike the baffle and then guided smoothly to exit sideways. This would serve the dual purpose of 1) absorbing noise and 2) smooth exit of air. .
Thus, using this concept, the mass flow rate of air would be higher for the given fan and fan cover design. This would ultimately lead to lower temperature rise. Also since air is smoothly guided over the baffle up to the exit, noise absorption would be higher and hence overall noise level of the motor would be lower.
The direction of air flow is depicted by arrows.

We claim,
1. A silencer mechanism for heat exchangers, said mechanism comprising:
a. air inlet means adapted to allow entry of air from an associated assembly;
b. air outlet means located on wails of said silencer mechanism for providing
exit of said entered air;
characterized in that, said silencer mechanism includes a streamlined guide baffle means adapted to smoothly guide air through said air outlet means.
2. A silencer mechanism as claimed in claim 1 wherein, said baffle means is a curvilinear baffle means.
3. A silencer mechanism as claimed in claim 1 wherein, said baffle means is a wave shaped baffle means with two laterally sloping edges.
4. A silencer mechanism as claimed in claim 1 wherein, said baffle means is a wave shaped baffle means with four circumferentially placed sloping edges.
5. A silencer mechanism as claimed in claim 1 wherein, said streamlined guide baffle means is a sound absorbent coated streamlined guide baffle means.
6. A silencer mechanism as claimed in claim 1 wherein, said streamlined guide baffle means is a foam coated streamlined guide baffle means.