WO2017042371A1

WO2017042371A1 - A fluid actuated fluid extraction system

Info

Publication number: WO2017042371A1
Application number: PCT/EP2016/071373
Authority: WO
Inventors: Andrew Smyth; David Smyth; Gerard Smyth; James Smyth; Peter Smyth
Original assignee: New World Energy Enterprises Ltd
Priority date: 2015-09-11
Filing date: 2016-09-09
Publication date: 2017-03-16
Also published as: GB201516110D0; AR105994A1; GB2542185A; US20180283713A1; EP3247950A1

Abstract

The present invention is concerned with a fluid actuated fluid extraction system, and in particular an airflow actuated gas extraction system which in use is located in an airflow such as a natural flow of wind, and which airflow actuates the system in order to extract fluid such as a gas from a remote location such as the interior of a building, the system comprising a hollow body having at least a pair of concentric annular baffles longitudinally spaced from one another to define an annular flow channel circumscribing the body between the pair of baffles into which an actuating fluid can flow from an exterior of the body, the body further having an intake to permit an exhaust fluid to enter the body longitudinally, wherein one or more of the baffles are profiled to generate a vortex within an upstream portion of the flow channel and to effect propagation of the vortex circumferentially around the channel by means of the coanda effect

Description

A fluid actuated fluid extraction system

Field of the invention

The present invention is concerned with a fluid actuated fluid extraction system, and in particular an airflow actuated gas extraction system which in use is located in an airflow such as a natural flow of wind, and which airflow actuates the system in order to extract fluid such as a gas from a remote location such as the interior of a building or the like. The extraction system of the invention could for example be integrated with an existing air conditioning and/or ventilation system in order to improve or augment the existing building infrastructure.

Background of the invention

Energy consumption is a worldwide concern which has serious implications for global warming and environmental degradation. As a result renewable or alternative forms of energy are becoming more and more important. The power or kinetic energy of wind is now a well established form of alternative energy, with wind turbines, both on and off shore, being the most well-established form of renewable energy.

While wind turbines are an effective use of this kinetic energy source, there are conceivably a considerable number of alternative uses to which wind power may be applied in order to save energy.

It is therefore an object of the present invention to provide a fluid, preferably wind, powered means of extracting or displacing another fluid, preferably air or the like, and to do so in a simple and cost effective manner.

Summary of the invention

According to the present invention there is provided a fluid actuated fluid extraction system comprising a hollow body having at least a pair of concentric annular baffles longitudinally spaced from one another to define an annular flow channel circumscribing the body between the pair of baffles into which an actuating fluid can flow from an exterior of the body; an intake to permit an exhaust fluid to enter the body longitudinally; characterised in that one or more of the baffles are profiled to generate a vortex within an upstream portion of the flow channel and to effect propagation of the vortex circumferentially around the channel by means of the coanda effect.

Preferably, the annular flow channel is open to an interior volume defined by the body. Preferably, the one or more baffles are profiled such that the vortex rotates in a direction which accelerates the exhaust fluid through the hollow interior of the body. Preferably, the one or more baffles comprise a lower edge, a throat and an upper edge, the lower edge having a larger diameter than the upper edge and the throat having a smaller diameter than the upper edge.

Preferably, the one or more baffles define a convergent divergent cross section relative to a longitudinal axis, in which the baffle converges radially inwardly from the lower edge towards the throat and diverges radially outwardly from the throat towards the upper edge.

Preferably, at least a divergent portion of the baffle has a curved profile. Preferably, at least the divergent portion defines a concave curvature with respect to an incident actuating fluid.

Preferably, adjacent baffles longitudinally overlap. Preferably, adjacent baffles overlap such that a lower edge of one baffle extends longitudinally beyond the throat of an adjacent baffle.

Preferably, adjacent baffles radially overlap. Preferably, the annular flow channel is shaped and dimensioned to accelerate and redirect the actuating fluid from an exterior to an interior of the body.

Preferably, the extraction system comprises a plurality of baffles defining three annular flow channels.

Preferably, one or more of the baffles comprise an array of circumferentially arranged apertures to permit fluid to flow from the respective flow channel, through the aperture, to an exterior of the body.

Preferably, the apertures are located adjacent the lower edge of the baffle.

Preferably, the intake is oriented such that the first fluid enters the body in a substantially longitudinal direction.

Preferably, the body comprises a top wall opposite and spaced from the intake.

Preferably, the top wall is longitudinally recessed below an upper edge of the uppermost baffle. Preferably, the top wall is recessed below the throat of the uppermost baffle.

Preferably, a circumferential gap is provided between an edge of the top wall and an adjacent baffle.

Preferably, the body is substantially symmetrical about an axial axis of revolution.

Preferably, the fluid extraction system comprises a frame securing the baffles relative to one another. Preferably, the frame retains the top wall.

Preferably, the fluid extraction system comprises a set of fan blades mounted on an interior of the body and operable to draw the exhaust fluid from the exhaust. Preferably, the fluid extraction system comprises one or more sensors operable to monitor one or more environmental conditions.

As used herein, the term "body" is intended to mean a structure which is primarily defined by one or more generally solid outer walls which thus define an interior space within the body, which may however be accessible from an exterior of the body through one or more openings in the walls defining the body.

As used herein, the term "upstream" is intended to define the location of a leading or forward portion of a flow channel with respect to the direction of flow of an actuating fluid such as the wind, which upstream portion will therefore vary depending on the direction from which the wind approaches the flow channel.

As used herein, the terms "upper" and "lower" and related terms refer to a particular position or location on the fluid extraction system when mounted in a working location and orientation in which a longitudinal axis of the generally cylindrical body is arranged in a generally vertical orientation.

Brief description of the drawings The present invention will now be described with reference to the accompanying drawings, in which;

Figure 1 illustrates a perspective view of a fluid extraction system according to a first embodiment of the present invention; Figure 2 illustrates a schematic sectioned side elevation of the fluid extraction system illustrated in Figure 1 ; Figure 3 illustrates a computational fluid dynamics representation of the system illustrated in Figure 1 , viewed normally to the direction of wind flow and showing the formation of tubular vortices; Figure 4 illustrates an alternative computational fluid dynamics representation of the system illustrated in Figure 1 , viewed in line with the direction of wind flow and again showing the formation of tubular vortices, and in which arrow length is representative of velocity;

Figure 5 illustrates an enlarged view of a portion of the representation illustrated in Figure 3;

Figure 6 illustrates a pressure curve plotting the negative pressure generated on the interior of the system for varying external wind speeds.

Figure 7 illustrates a perspective view of a fluid extraction system according to an alternative embodiment of the present invention;

Figure 8 illustrates a schematic sectioned side elevation of the fluid extraction system illustrated in Figures 7; Figure 9 illustrates a section side elevation of the fluid extraction system illustrated in Figure 7;

Figure 10 illustrates a computational fluid dynamics representation of the system illustrated in Figure 7, viewed normally to the direction of wind flow and showing the formation of tubular vortices; and Figure 1 1 illustrates an alternative computational fluid dynamics representation of the system illustrated in Figure 7, viewed in line with the direction of wind flow and again showing the formation of tubular vortices, and in which arrow length is representative of velocity;

Detailed description of the drawings

Referring now to Figures 1 to 5 of the accompanying drawings there is illustrates a fluid actuated fluid extraction system according to a first embodiment of the invention, generally indicated as 10, for use in extracting an exhaust fluid such as a gas from a remote location by means of an actuating fluid, for example a natural flow of wind or the like, which is used to actuate the extraction system 10 as hereinafter described.

The extraction system 10 is particularly but not exclusively intended to be located in a gas flow such as a natural flow of wind to define the actuating fluid flow, which during operation flows through the system 10 as hereinafter described, in order to actuate the system 10 to extract an exhaust fluid such as a gas from the remote location. The extraction system 10 is adapted, as detailed hereinafter, to generate a reduced or negative pressure on an interior of the system 10 through the action of augmenting the direction and velocity of the wind passing thought the system 10, in order to effectively generate suction within the system 10 which can be employed to extract an exhaust gas from a remote location. In one application the system 10 could for example be mounted to an exterior of a building (not shown) or the like, preferably at a height such as on the roof of the building in order to avail of higher wind speeds, and used to ventilate the building by extracting air from one or more interior spaces of the building. The system 10 may therefore be integrated with a new or existing air conditioning and/or ventilation system (not shown) of the building. A person skilled in the art will of course understand that the system 10 will have many other alternative or complimentary applications.

The system 10 comprises a hollow cylindrical body 12, the system 10 preferably being mounted, in use, such that a longitudinal axis is substantially vertically oriented. The body 12 comprises an array of longitudinally stacked annular baffles 14, 16, 18, 20 spaced from one another to define an array of annular flow channels 22, 24, 26 between adjacent pairs of the baffles as described in greater detail hereinafter. The baffles 14, 16, 18, 20 give the body 12 a segmented form and are adapted through shape and orientation to perform a dual function, both accelerating and redirecting the natural flow of wind from an exterior to an interior of the body 12 in order to effect a pressure reduction within the body 12, while also effecting the generation of vortices within the flow channels 22, 24, 26 which, again as will be described in detail hereinafter, serve to further accelerate the exhaust fluid through the interior of the body 12. The acceleration results in a reduction in the local pressure of the air flow, which can then be utilised in order to extract the exhaust fluid, in particular a gas, from a remote location via an intake 28 forming, in use, a lower end of the body 12. The cylindrical form of the body 12 presents an unchanging profile and thus functionality regardless of the angle of approach of the natural flow of wind, ensuring that the system 10 will operate consistently irrespective of the direction of the prevailing wind. This avoids the requirement for the system 10 to track the prevailing wind, and allows the design of the system 10 to be devoid of moving parts, simultaneously increasing the simplicity and effectiveness thereof. The intake 28 is in the form of a short pipe or spigot and in use is suitably secured to the downstream end of a duct (not shown) having a upstream end (not shown) located at the remote location from which a fluid such as a gas is to be extracted, the intake 28 providing access to the hollow interior of the body 12. The duct (not shown) connected to the intake 28 may be terminated in any suitable fitting, for example a conventional exhaust air grill (not shown) at the upstream end. The reduced local pressure on the interior of the body 12 will result in a pressure differential between the upstream end of the duct and the intake 28 located at the downstream end. This pressure differential effectively creates suction which will result in gas or other fluid being extracted from the remote location through the duct to exit via the intake 28 and become entrained within the actuating fluid, again preferably in the form of accelerated wind flowing through the body 12. The intake 28 preferably enters the body 12 in a longitudinal direction and in use results in the exhaust gas flow substantially vertically upward into the interior space of the body 12. The body 12 preferably additionally comprises a top wall or roof 30 opposite and spaced from the intake 28 which provides weather proofing for the system 10 in order to reduce the ingress of precipitation and other foreign objects, for example bird or animal life, from the interior of the body 12. It should therefore be understood that the roof 30 could be omitted, in particular in locations or environments where rainfall or other precipitation is not an issue. The outer edge of the top wall 30 is preferably spaced from the adjacent baffle 20 in order to permit air to flow upwardly through said circumferential gap, as will be described. However as will also be described, any precipitation which may pass downwardly through this gap will nevertheless be vented from the interior of the body 12 by means of the airflow through the body 12 and will not therefore be able to enter

The various components of the system 10 are secured relative to one another, in the embodiment illustrated, by means of a frame 32. The frame 32 extends upwardly from the lowermost baffle 14 to retain each of the remaining baffles 16, 18, 20 and the roof 30 in position relative to one another. The frame 32 is of minimalist construction in order to minimise the affect on the airflow through the body 12. It will of course be understood that the frame 32 may be of any other suitable form once capable of embodying the above mentioned functionality. In addition it will be understood that, while a more complex manufacturing operation, the system 10 could be moulded or otherwise produced as a single piece, for example using 3D printing or the like, although for commercial and logistical reasons such as transport and storage, it is preferable that the system 10 is manufactured in sections which can then be assembly into the finished system 10, whether onsite or elsewhere.

Turning then to the operation of the system 10, the array of longitudinally stacked baffles 14, 16, 18, 20 are designed to augment the flow of the passing wind or other actuating fluid, in order to accelerate and redirect the wind which flows between the baffles 14, 16, 18, 20. In particular the baffles 14, 16, 18, 20 each comprise a solid surface such as to present a barrier to the direct passage of the actuating fluid through the body 12, the actuating fluid conventionally flowing and approaching the system 10 in a substantially horizontal direction. The baffles 14, 16, 18, 20 extend longitudinally from a lower edge 34 to an upper edge 36, with a throat 38 defining a region at which the curve of the respective baffle reverses from having a positive angle relative to the oncoming wind to a negative angle where the baffle diverges radially outwardly from the throat 38 towards the upper edge 36. The radially convergent portion between the lower edge 34 and the throat 38 is of significantly greater length than the divergent portion extending between the throat 38 and the upper edge 36, and acts to redirect the oncoming wind from a substantially horizontal direction to a substantially vertical direction before flowing upwardly over the upper edge 36 and into the interior of the body 12, such that the actuating fluid is then flowing in a substantially longitudinal or, in use, vertical direction and thus in line with the exhaust fluid entering the body 12 via the intake 28. As the incoming wind is redirected by the baffles 14, 16, 18, 20 it is also accelerated by virtue of the shape and dimensions of each flow channel 22, 24, 26 and thus experiences a reduction in pressure which then effects the pressure differential between the interior of the body 12 and the upstream end of the duct which the system 10 is servicing, in order to generate a positive displacement of fluid through the duct to be exhausted via the system 10.

The curvature of the baffles 14, 16, 18, 20 serves to reduce boundary layer separation of the incoming wind, and by redirecting the wind to flow into the interior of the body 12 in a substantially longitudinal or axial direction, turbulence is reduced as this air flow mixes with the exhaust gas entering via the intake 28. Reducing the turbulence serves to increase the degree to which the exhaust gas becomes entrained within the redirected wind flow which, combined with the reduced pressure at the interior of the body 12, improves the extraction efficiency of the system 10.

In addition to the above redirection and acceleration, the baffles 14, 16, 18, 20 further augment the oncoming wind in order to provide a further improvement to the extraction efficiency of the system 10. In particular the reversing orientation of each of the baffles 14, 16, 18, 20 from the convergent to the divergent portions, with respect to the direction of flow of the oncoming wind, forces the oncoming wind to reverse in direction as it flows across the throat 38 and back along the divergent portion before flowing over the upper edge 36. This reversal in direction, along with the concave curvature of the divergent portion, results in the generation of a vortex of the incoming wind, located adjacent the upper edge 36,and within the respective flow channel 22, 24, 26, the vortex being formed and retained between adjacent pairs of baffles 14, 16, 18, 20. This vortex is initially formed at the leading or upstream region of the baffles 14, 16, 18, 20 with respect to the oncoming wind, but the baffles 14, 16, 18, 20 are shaped to promote the progression or extension of the vortex radially around the respective baffle, in both directions, as a result of the coanda effect. As a result the vortex ultimately establishes a tube or torus of swirling air substantially extending around the circumference of the annular flow channel 22, 24, 26, as for example illustrated in Figure 3 in which the oncoming wind is flowing from right to left, the vortex initially forming at the "front" or "upstream" portion of the baffle 14 at the right hand side of the image and then progressing around the baffle14 towards the "rear" or "downstream" portion of the baffle 14 on the left hand side of the image. This lowermost vortex is also illustrated, in section and at two opposed portions, in Figure 4. The tubular vortex is formed and remains above the upper edge 36 of the respective baffle and thus is positioned to interact with the flow of exhaust gas entering the interior of the body 12. The vortices thus transfers energy to the exhaust gas in order to increase the velocity of this exhaust gas. The exhaust gas is then accelerated up and out through the various openings provided about the segmented body 12, for example between the upper wall 30 and the adjacent baffle 20, and a large proportion becomes entrained within the vortices and is thus vented outwardly through the flow channels 22, 24, 26 between adjacent baffles to the exterior of the body 12. It will thus be appreciated that as a result of the coanda effect, enabling each vortex to adhere to the respective baffle and thus form a torus extending from a "front" to "rear" or upstream to downstream side of the body 12, the accelerating effect of the vortices is applied around a significant proportion of the circumference of the body 12 in order to increase the extraction efficiency. Without this effect the vortex would form only at a "front" or upstream portion of the baffles 14, 16, 18, 20 with respect to the oncoming wind, thus dramatically reducing the extraction efficiency.

In addition to improving the extraction efficiency, the augmented air flow generated by the baffles 14, 16, 18, 20, in particular the presence of the tubular vortices, act to eject wind driven rain or other precipitation which might enter the interior of the body 12, despite the presence of the upper wall 30 and the over lapping baffles 14, 16, 18, 20. Any such precipitation is entrained into the airflow within the body and thus ultimately ejected outwardly from the interior volume of the body 12 at the gaps between adjacent baffles. The presence of the upper wall or roof 30 does however significantly reduces the entry of precipitation.

In addition to providing weather proofing, the longitudinal positioning of the roof 30 below the upper edge 36 of the upper most baffle 20 is important in allowing the upper most vortex to develop and run without being hindered. The roof 30 is preferably positioned below the throat 38 of the uppermost baffle 20 and above the upper edge 36 of the adjacent baffle 18. The exact longitudinal position of the roof 30 may however be varied to suit particular environmental conditions or operational requirements. The system 10 will however function in the absence of the roof 30, which may therefore be omitted, for example in locations or environments where the entry of precipitation is not a significant issue. In order to provide an addition source of air flow to feed and maintain the vortices, the baffles 14, 16, 18, 20 are preferably provided with an annular array of openings 40, preferably located adjacent the lower edge 34 of the respective baffle, which provide ports through which exterior air flow may be drawn into the flow channels to become entrained in the vortices, for example as illustrated by the computational fluid dynamics illustrations of Figures 3 and 5, in which airflow can be seen to enter through the opening 40 on the left hand side of the image to feed vortex formation.

As detailed above , the baffles 14, 16, 18, 20 longitudinally overlap, a lower edge 34 of each baffle 16, 18, 20 extending below an upper edge 38 of each adjacent baffle 14, 16, 18 in order to prevent the direct flow of wind between adjacent baffles 14, 16, 18, 20. The level of overlap between adjacent baffles 14, 16, 18, 20 may be varied in order to alter the performance of the system 10, and in a preferred embodiment the lower edge 34 of each baffle 16, 18, 20 extends beyond a throat 38 of each adjacent baffle 14, 16, 18. This allows the vortices to be formed behind the protective barrier of the overlapping lower portion of the adjacent baffle, preventing the oncoming wind from directly impacting the vortex which would negatively affect the formation an maintenance thereof. The range of overlap may vary, and may vary from one set of adjacent baffles to the next. A baffle may overlap an adjacent baffle by between -50% and 99%. A minus overlap signifies that the lower edge 36 of a baffle is longitudinally spaced from the upper edge 38 of the adjacent baffle, such that the baffles can be said to be "loosely" stacked, while the more positive the overlap the "tighter" the baffles are stacked and thus the greater the overlap. It will be appreciated that the number, dimension, shape and relative positions of the baffles 14, 16, 18, 20 may be varied as required, although the provision of four baffles 14, 16, 18, 20 in order to define three flow channels 22, 24, 26 has been found to provide the greatest efficiency in accelerating and redirecting the natural flow of air into the interior of the body 12. The system 10 will however operate with only a pair of baffles defining a single flow channel in which the above described tubular vortex will form. However by having multiple baffles and flow channels, multiple vortices are formed one about the other, significantly increasing the acceleration and ejection of the exhaust fluid from the interior of the body 12. In use the system 10 is mounted at a location, for example on the roof of a building or the like, at which wind or another actuating fluid flow can freely pass and through the segmented body 12. The intake 28 may be used to mount the system 10, or another suitable form of mounting (not shown) may be employed. The intake 28 then provides the interface to a remote location (not shown) from which an exhaust fluid, in particular a gas such as air, is to be extracted, for example for ventilation purposes. The opposed end of the ducting to which the intake 28 is connected, for example an existing ventilation duct of a building, may be terminated with an exhaust air grill (not shown) or the like. Alternatively the system 10 may be mounted to or formed integrally with an air handling until such as condenser, air conditioning unit or other HVAC system, in particular in buildings such as residential apartment blocks, office buildings, manufacturing plants, etc, in order to increase the air flow through such air handling units and thus improve the operation and/or efficiency of same.

Figure 5 illustrates a pressure curve plotting the negative pressure generated on the interior of the system 10 for varying external wind speeds, which negative pressure creates the pressure differential with the remote location from which an exhaust gas is to be extracted. A suitable vent or volume control damper valve (not shown) may be located at any position along the ducting or within the intake 28, in order to permit the intake 28 to be opened or closed in order to regulate the extraction of gas. Additionally or alternatively a conventional fire damper assembly (not shown) may be located in line within the intake 28 as is conventional practice in ventilation and air conditioning ducting. As a further alternative, the system 10 may integrate with an existing volume control damper valve or fire damper assembly. The system 10 may then comprises one or more sensors (not shown) and associated control system (not shown), preferably provided about the body 12, which sensors are operable to monitor the external environmental conditions, such as air temperature, humidity, wind speed, etc, the control system being arranged to effect operation of the above mentioned volume control damper in response to certain environmental conditions. For example if the external air temperature drops below a pre-set level, the control system may be arranged to partially or fully close the volume control damper in order reduce heat loss through the system 10 to the exterior. Once the system 10 is in position and any such vent or valve opened, wind will flow towards and through the segmented body 12, and regardless of the direction from which the wind approaches, the system 10 will operate consistently and as described above. Referring now to Figures 7 to 1 1 of the accompanying drawings there is illustrated a fluid actuated fluid extraction system according to an alternative embodiment of the present invention, generally indicated as 1 10, which is again for use in extracting an exhaust fluid such as a gas from a remote location. In this alternative embodiment like components have been recorded like reference numerals and unless otherwise stated perform a like function as the corresponding feature of the first described embodiment.

The extraction system 1 10 comprises a hollow cylindrical body 1 12 which, as with the previous embodiment, is preferably mounted such that a longitudinal axis of the body 1 12 is substantially vertically oriented. The body 1 12 comprises an array of longitudinally stacked annular baffles 1 14, 1 16, 1 18, spaced from one another in order to define an array of annular flow channels 122, 124, between adjacent pairs of the baffles. The baffles 1 14, 1 16, 1 18 give the body 1 12 a segmented or louvered form and are adapted through shape and orientation to perform a dual function. The baffles both accelerate and re-direct the natural flow of wind from an exterior of the body 1 12 into an interior of the body 1 12 in a manner which affects a pressure reduction within the interior space defined by the body 1 12, while also affecting the generation of vortices within the flow channels 122, 124 which further accelerate the exhaust fluid through the interior of the body 1 12. This acceleration effects a reduction in the local pressure of the airflow which is utilised in order to affect a pressure differential between the interior of the body 1 12 and the remote location from which the exhaust fluid is to be extracted, causing the exhaust fluid to flow from the remote location into the interior of the body 1 12 via an intake 128 forming a lower end of the body 1 12. The intake 128 is preferably in the form of a short section of pipe formed integrally with the lower most baffle 1 14 and extending longitudinally into the interior space defined by the body 1 12. The lower end of the intake 128 provides a connection point for an exhaust duct (not shown) or the like which can thus be connected between the system 1 10 and the remote location in order to facilitate the transfer of exhaust gas.

The body 1 12 of the system 1 10 comprises a top wall in the form of a roof 130 opposite to and spaced from the intake 128 which provides both weather proofing to the system 1 10 in addition to augmenting the airflow passed the upper end of the system 1 10. The system 1 10 additionally comprises a frame 132 to which the various preferably moulded parts of the body 1 12 are secured, including the roof 130.

In operation, the longitudinally stacked baffles 1 14, 1 16, 1 18 define an augmenting barrier or surface which prevents the direct passage of the oncoming wind to the interior of the body 1 12, deflecting the oncoming wind from a substantially horizontal incoming direction to essentially reverse in direction from flowing over a lower edge 134 to an upper edge 136, via a throat 138. In this way the respective baffle serves to redirect the oncoming airflow against the underside of the immediately adjacent upper baffle which acts to deflect the airflow downwardly, thus causing the formation of a vortex in the respective flow channel 122, 124. This vortex is initially formed at the leading or upstream region of the respective flow channel 122, 124 with respect to the oncoming wind, but the baffles 1 14, 1 16, are shaped to promote the progression and adhesion of this vortex radially around the respective flow channel, in both directions, as a result of the coanda effect. Thus the vortex extends to form a partial or full tube or torus of swirling air substantially extending around the circumference of the respective flow channel 122, 124. This tubular vortex interacts with the incoming flow of exhaust gas entering the interior of the body 1 12 via the intake 128, accelerating the exhaust gas, reducing the pressure thereof and pushing the exhaust gas upwardly and outwardly through the various openings in the body 1 12.

As with the first described embodiment, the baffles 1 14, 1 16, 1 18 may be provided with an annular array of openings 140 preferably located adjacent the lower edge 134 of the respective baffle, which openings 140 permit exterior airflow to be drawn into the flow channels to become entrained within each of the vortices.

Although in this embodiment three of the baffles 1 14, 1 16, 1 18 are arranged to define two flow channels 122, 124, the number, dimension and shape of the baffles 1 14, 1 16, 1 18 may be varied as long as there are at least two of the baffles in order to define at least 1 annular flow channel.

The system 10; 1 10 may additionally comprise a set of turbine blades (not shown) and/or a set of fan blades (not shown) provided within the interior space of the body 12; 1 12. The set of turbine blades may be positioned to have a horizontal or a vertical axis, and to be driven by the exhaust gas flowing upwardly through the intake 28; 128 and/or the natural flow of air passing through the segmented body 12; 1 12. The fan blades (not shown) are preferably provided as an inline fan at or adjacent the intake 28; 128, and may be electrically or otherwise operated in order to supplement the action of the natural flow of air through the body 12; 1 12 in order to effect extraction of the exhaust fluid. It will be appreciated that the cylindrical shape of the body 12; 1 12 ensures that the flow path through the body 12; 1 12 that is presented to the oncoming wind, regardless of the direction that the wind approaches the system 10; 1 10, will be the same. As a result the system 10; 1 10 is omnidirectionally operational, and thus requires no moving parts in order to track the prevailing wind, greatly improving the simplicity and effectiveness of the system 10; 1 10.

Claims

A fluid actuated fluid extraction system comprising a hollow body having at least a pair of concentric annular baffles longitudinally spaced from one another to define an annular flow channel circumscribing the body between the pair of baffles into which an actuating fluid can flow from an exterior of the body; an intake to permit an exhaust fluid to enter the body longitudinally; characterised in that one or more of the baffles are profiled to generate a vortex within an upstream portion of the flow channel and to effect propagation of the vortex circumferentially around the channel by means of the coanda effect.

A fluid actuated fluid extraction system according to claim 1 in which the annular flow channel is open to an interior volume defined by the body.

A fluid actuated fluid extraction system according to claim 1 or 2 in which the one or more baffles are profiled such that the vortex rotates in a direction which accelerates the exhaust fluid through the hollow interior of the body.

A fluid actuated fluid extraction system according to any preceding claim in which the one or more baffles comprise a lower edge, a throat and an upper edge, the lower edge having a larger diameter than the upper edge and the throat having a smaller diameter than the upper edge.

A fluid actuated fluid extraction system according to claim 4 in which the one or more baffles define a convergent divergent cross section relative to a longitudinal axis, in which the baffle converges radially inwardly from the lower edge towards the throat and diverges radially outwardly from the throat towards the upper edge.

6. A fluid actuated fluid extraction system according to claim 5 in which at least a divergent portion of the baffle has a curved profile.

7. A fluid actuated fluid extraction system according to claim 6 in which at least the divergent portion defines a concave curvature with respect to an incident actuating fluid.

8. A fluid actuated fluid extraction system according to any preceding claim in which adjacent baffles longitudinally overlap.

9. A fluid actuated fluid extraction system according to claim 8 in which adjacent baffles overlap such that a lower edge of one baffle extends longitudinally beyond the throat of an adjacent baffle.

10. A fluid actuated fluid extraction system according to any preceding claim in which adjacent baffles radially overlap.

1 1. A fluid actuated fluid extraction system according to any preceding claim in which the

annular flow channel is shaped and dimensioned to accelerate and redirect the actuating fluid as it flows through the annular flow channel from an exterior to an interior of the body.

12. A fluid actuated fluid extraction system according to any preceding claim comprising a

plurality of baffles defining three annular flow channels.

13. A fluid actuated fluid extraction system according to any preceding claim in which one or more of the baffles comprise an array of circumferentially arranged apertures to permit fluid to flow from the respective flow channel, through the aperture, to an exterior of the body.

14. A fluid actuated fluid extraction system according to claim 13 in which the apertures are located adjacent the lower edge of the baffle.

15. A fluid actuated fluid extraction system according to any preceding claim in which the intake is oriented such that the first fluid enters the body in a substantially longitudinal direction.

16. A fluid actuated fluid extraction system according to any preceding claim in which the body comprises a top wall opposite and spaced from the intake.

17. A fluid actuated fluid extraction system according to claim 16 in which the top wall is

longitudinally recessed below an upper edge of the uppermost baffle.

18. A fluid actuated fluid extraction system according to claim 16 or 17 in which the top wall is recessed below the throat of the uppermost baffle.

19. A fluid actuated fluid extraction system according to any of claims 16 to 18 in which a

circumferential gap is provided between an edge of the top wall and an adjacent baffle.

20. A fluid actuated fluid extraction system according to any preceding claim in which the body is substantially symmetrical about an axial axis of revolution.

21. A fluid actuated fluid extraction system according to any preceding claim comprising a frame securing the baffles relative to one another.

22. A fluid actuated fluid extraction system according to claim 21 in which the frame retains the top wall.

23. A fluid actuated fluid extraction system according to any preceding claim comprising a set of fan blades mounted on an interior of the body and operable to draw the exhaust fluid from the exhaust.

24. A fluid actuated fluid extraction system according to any preceding claim comprising one or more sensors operable to monitor one or more environmental conditions.