Patent Application
20170328565
The present invention is related to a roof mounted wind boosted static ventilator for removing exhaust gases from enclosed spaces to the atmosphere, the ventilator comprising a ventilation duct having openings that are slightly inclined at a predetermined angle with respect to the vertical axis of said ventilation duct, a shroud surrounding said ventilation duct and guide vanes. The guide vanes act as physical barrier and divide the area between the shroud and the ventilation duct into a plurality of compartments having equal number of said openings, wherein the pressure gradient boosts the flow of exhaust gases out of the buildings.
Systems using natural ventilation are already known as it dates back to as old as the Neolithic period as evident from purpose-built ventilations in China found to be built at that time. It is only in the past 150 years that the mechanical ventilation has been used. Prior to that period, all enclosures and buildings were naturally ventilated. These mechanical systems used alongside natural ventilations are crude compared to modern systems used nowadays.
Modern buildings are very demanding in which all standards of health and comfort have to be met, provided that they satisfy low energy consumption and sustainability. Modern ventilation and air conditioning systems focus on the economic use of floor space and for maintaining the productivity of the occupants. But these are only limited to residential and office buildings. When it comes to big industries, factories and storage facilities, the only practical and economical solution is using natural ventilation systems.
Traditional Static integrated-building ventilation systems are bulky, ineffective and vulnerable to dust accumulation, birds and vermin infestation. Nowadays there is a build-up of rotary ventilators which uses the wind energy to rotate and expel the hot air. However, the actual performance falls to reach the expectations since the ventilation system functions on the basis of buoyancy effects rather than rotational effects, and is dependent on wind directions. Moreover, these rotating units have bearings in it which gets eroded, and worn out which further increases the maintenance cost.
WO 2014/161029 describes a static ventilator system that uses wind induction effects to remove exhaust gases from enclosed spaces. This ventilator equipment has vertical slots in its duct which is covered by a shroud using vertical hollow brackets. The main problem faced by using this ventilator system is that the pressure difference created by the wind over the windward side and the leeward side are equalized all inside the space between the duct and the shroud and thus it becomes ineffective for the removal of exhaust gases by induction.
To address these problems, several approaches have been disclosed before, but none was found satisfactory.
Therefore there is a need to provide an improved ventilation system to overcome all the above mentioned concerns.
It is an object of the present invention to provide a static ventilator apparatus able to withstand all the problems and limitations mentioned above. Said static ventilator apparatus is adapted to be mounted on the roof of the building or enclosed spaces.
As a first aspect of the present invention, there is provided a ventilation apparatus for for removing exhaust gases from inside enclosed spaces to the atmosphere, said ventilation apparatus comprising:
In a further aspect of the present invention, the ventilation duct and the shroud have a cylindrical shape and are concentric with respect to each other.
In a still other preferred embodiment, the ventilation apparatus further comprises a covering plate located on the top of the shroud. Preferably, the covering plate has a plate diameter and the shroud has a shroud parameter, the plate diameter being smaller than the diameter of the shroud. More preferably, wherein the diameter ratio between the covering plate diameter with respect to the shroud diameter is within the range of 1.0:1.1 to 1.0:1.5; being most preferably, 1.0:1.2.
In another preferred embodiment of the present invention, the openings are inclined at an angle ranging from 10 to 30 degrees with respect to the central axis of the ventilation duct. Preferably, the openings are inclined at an angle of 17 degrees with respect to the central axis of the ventilation duct.
In a still other preferred embodiment of the present invention, the pressure plate, the ventilation duct and the shroud are coupled to the guide vanes in such way that said guide vanes give rigidity to the whole ventilation apparatus. Preferably, the shroud has a shroud top, a shroud bottom, a surrounding wall and a height between the top and the bottom of the shroud, wherein said guide vanes about the surrounding wall and extend vertically along the height of the shroud from the bottom until the top of the shroud and the covering plate, thereby forming the compartments having a height equivalent to the height of the shroud.
In another preferred embodiment of the present invention, the guide vanes are inclined at an angle ranging from 25 to 45 degrees with respect to the radial axis of the ventilation duct. Preferably, the guide vanes are inclined at an angle of 30 degrees with respect to the radial axis of the ventilation duct.
In a still preferred embodiment of the present invention, the openings are grouped in a plurality of groups, each group comprising a number of adjacent openings, where each compartment comprises a single group and an equal number of openings. Preferably, each group comprises from 6 to 12 openings. More preferably, each group comprises 9 openings.
In a still preferred embodiment of the present invention, the number of compartments ranges between 4 to 10 compartments, preferably, 6 compartments.
The ventilation apparatus of the present invention exhibits improved performances by having superior air flow rates and therefore able to efficiently remove exhaust gases from the enclosures to the atmosphere using pressure gradient. The ventilation apparatus of the present invention is configured to be mounted on the roof of any building facilities.
As illustrated in
As illustrated in
The ventilation apparatus 1 further comprises a plurality of guide vanes 5 extending outwardly and transversally with respect to the central axis between the external wall of the ventilation duct 2 and the shroud. Said guide vanes 5 are placed between each adjacent group of openings. The implementation of the guide vanes 5, which is considered one of the preferred embodiments of the present invention, has a dual purpose. The guide vanes 5 act as physical barriers to the wind and divide the area inside the ventilation apparatus 1 into a plurality of compartments 8 (see
The ventilation duct 2 is covered on the top by a pressure plate 4 which accelerates the air flow through the openings 5.
On the top of the outer shroud 3, there is provided a covering plate 6. As illustrated in
The top of the shroud is preferably raised up to 30 mm in heightheight to improve the wind induction effect and reduce the possibility of ingress from the rain.
As illustrated in
The pressure plate 4, the ventilation duct 2 as well as the shroud 3 are supported by the guide vanes 5 which give rigidity to the whole ventilation apparatus 1. The guide vanes 5 have a dual purpose, not only they act as a support to the entire ventilation apparatus 1 but they also help in the flow of exhaust gases out of the ventilation unit 1.
In a preferred embodiment of the present invention, the guide vanes 5 have a concave surface on one end to fit into the outer shroud and a convex plane on the other end in order to support the ventilation duct 2.
The guide vanes 5 are inclined at an angle ranging from 25 to 45 degrees with respect to the radial axis of the ventilation duct, preferably at 30 degrees. The radial axis is an axis extending radially from the cylindrical wall of the ventilation duct perpendicularly to the central axis. The inclination of said guide vanes 5 helps to reduce the possibility of rain splashing into the flow stabilizer openings and smoothing the air flow path.
The guide vanes 5 also act as streamlined body which helps the turbulent exhaust gases inside the enclosed space to flow over them smoothly by accelerating the conversion of turbulent flow into transitional flow, thereby reducing the turbulent viscosity and smoothing the flow of exhaust gases out through the ventilation duct 2. The guide vanes 5 also help in retaining the pressure gradient in the area between the ventilation duct 2 and the shroud 3, by dividing the area into number of compartments 8, thereby not allowing the pressure gradient to normalize, which usually occurs in known static ventilation apparatus thereby decreasing their performance.
By the arrangement of the guide vanes 5 mentioned above, the overall performance of the ventilation apparatus 1 is increased, hence allowing a greater flow of exhaust gases through the ventilation duct 2 out of the buildings.
In a preferred embodiment of the present invention, the whole ventilation duct 2 is covered by a shroud 3 which forms the outermost part of the arrangement and also the one which faces wind. This part also has two significant purposes. The first and the most important one is the creation of a pressure gradient across the shroud 3. The wind produces a pressure gradient across the front and rear surfaces of the ventilation apparatus 1 in the line of wind by creating a low pressure wake on the leeward side.
The pressure gradient is used to remove exhaust gases from the enclosed space to the atmosphere. Said pressure gradient is retained throughout the process by using the guide vanes 5 as described above, i.e. by dividing the ventilator apparatus 1 into different compartments 8 as mentioned above.
The ventilation duct 2 comprises openings 7 that are slightly inclined at a pre-defined angle with respect to the central axis of said ventilation duct 2 and which forms the base of the ventilation apparatus 1 and facilitates the removal of exhaust gases through the same due to pressure gradient developed across the shroud 3. This pressure gradient is caused by the wind over the shroud 3 by creating a high pressure zone on the windward side and a low pressure wake zone on the downward side of the shroud 3.
The shroud 3 is also covered on the top by a covering plate 6 which is used to prevent entry of rainfall into the ventilation duct 2 and also to keep birds and vermin away. The covering plate 6 is also attached onto the guide vanes 5 which provide strength and rigidity to the entire ventilation apparatus 1. The wind airflow is maintained over said covering plate 6 thus preventing any recirculation of the exhaust gases from the air flow separated over the shroud 3.
In a preferred embodiment of the present invention, the guide vanes 5 extends along the height of the shroud 3 from the bottom till the covering plate 6, thereby creating compartments 8 having the same height as the shroud 3.
In a still preferred embodiment of the present invention, and for improved pressure gradient created in the departments 8, the guide vanes 5 should not have any openings and/or hollow in their surface.
As a conclusion, the ventilation apparatus 1 utilizes the compartments 8 created by the guide vanes 5 along with the ventilation duct 2 to retain the pressure gradient created as a result of local air flow pressure zones across the front and rear sides of the ventilation apparatus 1, i.e. the high pressure region created over the windward side and the low pressure wake region on towards the downward side. Said pressure gradient retained by the compartments 8 thus boosts up the movement of exhaust gases out of the enclosed space, thereby increasing the flow rate and improving the overall performance of the ventilation apparatus 1.
The Guide vanes 5 and the openings 7 improve the performance characteristics of the overall unit 1. Since there are no moving parts thereof, it is not susceptible for any mechanical wear and/or tear. Therefore the ventilation apparatus 1 of the present invention has shown to be capable of improving its performance with superior air flow rates than any other static or rotary ventilators.
While the invention has been made described in details and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various additions, omissions, and modifications can be made without departing from the spirit and scope thereof
In particular, although the description has specified certain characteristics and parts that may be used in the apparatus of the present invention, those skilled in the art will appreciate that many modifications and substitutions may be made. Accordingly it intended that all such modifications, alterations, substitutions and additions be considered to fall within the spirit and scope of the invention.
