DESC:FIELD OF INVENTION
The present invention relates to modifications pertaining to the kitchen chimney/ cooker hood. More particularly, the present invention discloses a reduced average noise power level in the kitchen chimney by 10 dB with ± 1dB tolerance, maintaining the flow rate level of the baseline of the existing BLDC chimney category.

BACKGROUND ART
Appliances with powerful motors can create too much noise in the kitchen. As per the survey, more than 50% of the consumers prefer a silent chimney in the kitchen to improve their cooking experience. Users complain that the kitchen chimneys disturb cooking and make it hard to stay in the kitchen for longer periods.

The main challenge is to reduce noise levels at higher speeds in the kitchen chimney without reducing airflow or suction. Blower system air throw is the primary noise-generating component in kitchen chimneys. Most chimneys use powerful blowers to provide excellent suction. The user is unwilling to compromise on suction but requires a quiet chimney.

In the prior art, a US specification US5983888 discloses a low-noise cooker hood. The low-noise hood is provided with housing with an air inlet and an air outlet. A first modular device in the form of an intake muffler with a first air duct passage extending through is mounted within the housing near the air inlet. A second modular device in the form of a discharge muffler with a second air duct passage extending through is mounted within the housing near the air outlet. The second air duct passage is shaped to prevent a straight, unobstructed passage for airflow through the second passage. A third device comprises an air-moving device that is secured by a mounting arrangement within the housing. A first vibration isolator, such as a plastic saddle, is provided in the mounting arrangement for the air-moving device for absorbing vibrations, and a second vibration isolator, in the form of a flexible connector, is positioned between the air-moving device and the second air duct passage. A third vibration isolator in a mounting arrangement for the discharge muffler may also be used.

In another prior art, a Chinese specification CN109140547 discloses a smoke exhaust. The smoke exhaust comprises a machine casing, a fan installed in the machine casing and an air guiding pipe installed in the machine casing. The fan is provided with an air inlet and an air outlet; the air guiding pipe is provided with an air inlet and an air outlet, and the air outlet of the air guiding pipe is linked to the air inlet of the fan. Noise reduction micro-holes are formed in the pipe wall of the air-guiding pipe. Noise generated during the running of the smoke exhaust permeates the noise reduction micro holes in the air guiding pipe when passing through the air guiding pipe and is reflected and forth several times in a space between the pipe wall of the air guiding pipe and the machine casing and then weakened after reflecting several times, and therefore a noise reduction effect is achieved on the smoke exhaust.

In contrast, the present invention introduces a "dual-in-one technology" in a new chimney configuration. Here, the suction path and air outlet are system-balanced designs that silently guide the exhaust air, thereby reducing noise by 10db. A high-noise-producing centrifugal blower is replaced with a twin blower, ensuring that airflow/suction is not compromised.

SUMMARY OF INVENTION
Most kitchen chimneys with high suction power make a lot of noise while operating, adding to noise pollution inside the house. A user is not ready to compromise on suction but needs a silent chimney. High suction capacity chimneys are directly related to a powerful blower system. It was observed that the blower is one of the major noise-producing components, along with airborne noises.

Therefore, such as herein described, there is provided a kitchen chimney/ cooker hood with reduced average noise power level comprising of a hood;
a dual in-one duct operably connected with a twin blower; a main body sub-assembly including top, middle and bottom glass sub-assembly; an inlet grill and an oil collector tray; wherein the said twin blower is powered using a common motor; and wherein the exhaust opening from the twin blowers are guided through “Dual in one exhaust duct”.

The current study focuses on optimizing the suction openings and modifying the suction path to reduce airflow obstacles. Along with the modified exhaust path, acoustic insulation material is also used at the chimney panels, thereby reducing the noise by 10dB with ± 1dB tolerance. In combination with optimizing the suction path and insulation, the normal blower that produces loud noise is replaced with a Centrifugal Twin Blower with a blade profile that produces lesser noise.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1 illustrates the Design of "Dual in One Technology", a new exhaust duct concept;
Fig 2 illustrates the Design of the optimized inlet grill in the new chimney design;
Fig 3 illustrates the exploded view of the new chimney design concept;
Fig 4 illustrates a pictorial representation of Dual in one exhaust duct in a new chimney design;
Fig 5 illustrates the Test report of the new chimney design;
Graph 1 illustrates a comparison of sound power level dB(A) of the existing chimney (baseline) and the new chimney design;

DETAILED DESCRIPTION
1. New exhaust connection duct concept:
A “Dual in one technology" is introduced in the new chimney configuration. Noise is a major concern for the existing chimneys in the market. To reduce the noise, a new idea is developed to remove the exhaust air from the kitchen silently.

Figure 1 depicts the detailed design of the "Dual in One technology concept". Referring to the ballooning in Figure 1, Section A-A. 1, The duct exhaust outlet has a diameter ranging Ø (150-160) mm for mounting the Aluminium duct or vent pipe, channels out the smoke, heat, and other impure gases silently out from Kitchen Chimney. 2 Thickness of the plastic/metal duct is defined as (2-3.5) mm. 3 The bottom inlet of the Dual in One duct has a diameter of Ø (160-180) mm, which is in line with the twin centrifugal blowers. 4, 5, 6, 7 - The outer radius of the duct is defined as R (10-15), R (50-63), R (200-223), and R (350-408) at different locations, helping in the smooth flow of air and thereby reducing airborne noise. 8 – The maximum length of the Dual in One duct is defined in the range of (500-600) mm. 9 - Height is defined in the range (325-375) mm.
2. Optimization of Inlet grill in new chimney design concept:
Figure 2 depicts the optimized design of the inlet grill in the new chimney concept. The inlet grill is modified to improve the suction and airflow. The length of the inlet grill ranges from (825-875) mm, and the height ranges from (180-225) mm.

Fig 3 shows an exploded view of the new chimney design concept. A study was conducted to evaluate the noise and airflow performance of the existing chimney design. The analysis showed that the major noise observed is due to airborne source excitations from the blower, followed by blower suction casing and discharge-induced noise.

To address the blower-induced noise, new technology, “Dual in one exhaust duct”, is introduced in the new chimney design concept; an optimized suction path using a dual duct helps silently move the air from the kitchen, thereby significantly eliminating the discharge-induced noise. A twin centrifugal blower is also considered in the new chimney design. The twin blower is powered using a common motor. The exhaust opening from the twin blowers is guided through the "Dual in one exhaust duct", as shown in Fig 4.

To conduct acoustic and flow simulations, simulation models of an existing chimney (baseline) and a new chimney were created. The performance of the new chimney configuration, considering noise and airflow as the main parameters, was compared and evaluated with the existing chimney.

It was observed that the noise power level of the new chimney design was reduced by 10dB(A) when compared with the existing baseline design. There was a significant reduction in airborne noises due to the optimization of exhaust duct configuration, as shown in Graph 1 in Fig 5, which compares the sound power level dB(A) of the existing chimney (baseline) and the new chimney design.

The above data shows that the suction capacity of the chimney improved with the adoption of dual-in-one technology and the replacement of the single blower with twin centrifugal blowers in the new chimney configuration.

Inventive step
1. High noise, a major concern in the existing chimneys on the market, is addressed in this work. Our new chimney concept achieves a silent chimney yet powerful suction.
2. A "Dual in one technology" is introduced in the new chimney design, which silently removes the exhaust air from the kitchen, thereby reducing total
chimney noise by 10dB.
3. This work will significantly contribute to reducing noise pollution in the environment.

Many modifications may readily be contemplated by those skilled in the art to which the invention relates. Many further modifications may readily be contemplated. The description set out above is particularly applicable to high-rate clarification applications. However, in conventional clarification where the upstream or downstream processes herein described are not used, the teachings according to the invention may have considerable merit and are also applicable. The specific embodiments described, therefore, should be taken as illustrative of the invention only and not as limiting its scope as defined herein.

,CLAIMS:

1. A kitchen chimney/ cooker hood with reduced average noise power level comprising of:
a hood;
a dual in-one duct operably connected with a twin blower;
a main body sub-assembly including top, middle and bottom glass sub-assembly;
an inlet grill and an oil collector tray;
wherein the said twin blower is powered using a common motor and
wherein the exhaust opening from the twin blowers is guided through a “Dual in one exhaust duct”.

2. The kitchen chimney/ cooker hood, as claimed in claim 1, wherein said inlet grill is modified by exposing more surface area to improve suction and airflow.

3. The kitchen chimney/ cooker hood, as claimed in claim 2, wherein the said length of the inlet grill ranges from (825-875) mm and the height ranges from (180-225) mm.

4. The kitchen chimney/ cooker hood, as claimed in claim 1, wherein said duct exhaust outlet has a diameter ranging Ø (150-160) mm for mounting the Aluminium duct or vent pipe, channels out the smoke, heat, and other impure gases silently out from Kitchen Chimney.

5. The kitchen chimney/ cooker hood, as claimed in claim 1, wherein the outer radius of the duct is defined as R (10-15), R (50-63), R (200-223), and R (350-408) at different locations, causing a smooth flow of air and thereby reducing airborne noise.

6. The kitchen chimney/ cooker hood, as claimed in claim 1, wherein the maximum length of the Dual in One duct is defined in the range of (500-600) mm. 9 - Height is defined in the range (325-375) mm.

7. The kitchen chimney/ cooker hood, as claimed in claim 1, wherein said, "Dual in one exhaust duct is configured to silently remove the exhaust air from the kitchen thereby reducing total chimney noise by 10dB.