GB2534656A

GB2534656A - Air mass induction device

Info

Publication number: GB2534656A
Application number: GB1520321.9A
Authority: GB
Inventors: Yan Sui-Hang; Se Camby; Lam Tony; Li Ricky; Wong Hannah; tang Tony
Original assignee: Ove Arup Partnership Ltd
Current assignee: Ove Arup Partnership Ltd
Priority date: 2014-11-20
Filing date: 2015-11-18
Publication date: 2016-08-03
Anticipated expiration: 2035-11-18
Also published as: GB201420657D0; GB201520321D0; HK1221276A1; GB2534656B

Abstract

An air mass induction device, such as a bladeless fan, comprises a housing 2 having a leading edge 4 and a trailing edge 6 extending in the longitudinal direction, where the housing comprises two opposing external surfaces 8a and 8b which taper towards the trailing edge 6, at least two nozzles 10a and 10b extending in the longitudinal direction of the housing such that at least one nozzle is associated with each opposing external surface and is arranged to direct air received from within the housing over the respective opposing external surface towards the trailing edge, to induce air from outside the housing to flow in the direction of the trailing edge. Preferably the housing comprises at least one internal chamber 12 in fluid communication with at least each nozzle. A method for air ventilation is also claimed.

Description

Air Mass Induction Device The present invention relates to an air mass induction device for use in indoor or outdoor spaces.

In places where the climate is humid and hot, air conditioning systems are used to provide thermally comfortable environments for indoor spaces. However, excessive use of air conditioning is detrimental to the environment. Alternative ways of achieving a thermally comfortable environment include the use of mechanical ventilation systems where the environment is improved by increasing air movement and ventilation rates. In this respect, mechanical fans can be used. However, they are often noisy to use and consume large amounts of electricity.

Similar issues are of concern in places where the climate is cold; air heating systems are used to provide thermally comfortable environments for indoor spaces.

A particular problem for hot or cold climates is the heating or cooling of outside spaces where people are stationary for periods of time, for example at bus stops, in theatre queues or in outdoor café areas. Patio heaters are often used in cold climates whereas mechanical fan units are often used in hot climates. These devices consume large amounts of energy.

US 2012/093630 Al is directed to a fan assembly. This fan assembly includes a nozzle and a system for creating a primary airflow through the nozzle. The nozzle includes an outlet for emitting the primary airflow, and defines an annular opening through which a secondary airflow from outside the fan assembly is drawn by the primary airflow emitted from the outlet. The fan assembly is bladeless and includes a DC brushless motor and a mixed flow impeller in order to create the primary airflow through the nozzle. The fan assembly is designed for use as a desk fan, for example.

The present invention seeks to provide an air mass induction device for indoor or outdoor spaces for providing air ventilation effects to these spaces.

According to the present invention, there is provided an air mass induction device comprising a housing having a leading edge and a trailing edge each extending substantially in the longitudinal direction of the housing, the housing comprising: two opposing external surfaces which taper towards the trailing edge; and at least two nozzles; wherein at least one nozzle is associated with each opposing external surface and is arranged to direct air received from within the housing over the respective opposing external surface towards the trailing edge, to induce air from outside the housing to flow in the direction of the trailing edge.

Preferably the air mass induction device of the invention has no integral or integrated mechanical or electrical parts, instead being a passive device relying on its aerodynamic design to assist in inducing the movement of a surrounding air mass, with air being driven into the device from a remotely-positioned source. This remotely-positioned source may be an air conditioning unit, an air heating unit or an air ventilating unit, by way of example.

The air mass induction device of the present invention is preferably not sized or configured as a portable device for domestic use; for example, it is not intended to be used as a desk fan. Preferably, no grilles are required.

The leading edge and the trailing edge extend substantially in the longitudinal direction of the housing.

The phrase 'extending substantially in the longitudinal direction of the housing' means extending in the general direction of the length of the housing. The length of the housing is generally perpendicular to the width of the housing, and the width of the housing is generally the direction of the housing from its leading edge to its trailing edge.

This width direction approximately corresponds to the direction of air flow. The housing also has a depth direction which is generally perpendicular to the longitudinal direction and to the width direction.

The two external surfaces oppose one another, meaning that there are opposing nozzles. The opposing nozzles are spaced from one another in a direction which is preferably substantially perpendicular to the length of the housing and/or is preferably substantially perpendicular to the width of the housing. In a preferred embodiment, the nozzles are spaced from one another in the depth direction.

The two opposing external surfaces taper towards the trailing edge, meaning that there is a continuous narrowing of the housing from the nozzles to the trailing edge. The two opposing external surfaces preferably each adjoin the trailing edge.

In a preferred embodiment, the nozzles are arranged adjacent to the leading edge of the housing. There is preferably a continuous narrowing of the housing from the leading edge to the trailing edge.

The leading edge and the trailing edge may be substantially linear in the longitudinal direction of the housing. However, the leading edge and the trailing edge may be non-linear or curvilinear; for example, these edges may each form either a wave-shape, a U-shape or a C-shape. The leading edge may have the same shape as the trailing edge or have a different shape to the trailing edge. The leading edge and the trailing edge are not annular in shape, nor are they loop-shaped, since they extend substantially in the longitudinal direction of the housing.

The housing preferably has a substantially uniform shape or area extending in the longitudinal direction of the housing, the uniform shape or area being the cross-sectional shape or area taken in the width direction through the air mass induction device: this means that, preferably, the housing does not taper along any part of its length. Similarly, the nozzle preferably does not taper along any part of its length.

Preferably the housing comprises at least one internal chamber (the housing may comprise multiple internal chambers) and each nozzle is in fluid communication with at least one internal chamber. The housing preferably comprises at least one air inlet which is also in fluid communication with at least one internal chamber. The housing is preferably elongate and may be linear in shape. The housing may be used in a horizontal or vertical orientation, for example.

The internal chamber or chambers are preferably empty of structural features such as noise reduction elements or wind screens or grilles.

In a preferred embodiment, the nozzles are arranged adjacent upstream ends of the two opposing external surfaces of the housing and the trailing edge is arranged adjacent downstream ends of the two opposing external surfaces of the housing. The opposing external surfaces of the housing preferably define a large surface area with respect to other external surfaces of the housing. The opposing external surfaces of the housing are preferably substantially planar. The nozzles and the trailing edge are preferably separated by the surface areas of the opposing external surfaces. Preferably the leading edge and the trailing edge are substantially separated by the surface areas of the opposing external surfaces.

The downstream ends of the two opposing external surfaces of the housing are the ends located in the direction in which the air flows.

The upstream ends of the two opposing external surfaces of the housing are those ends located in the direction opposite to that in which the air flows.

The (downstream) ends of the two opposing external surfaces of the housing preferably meet at the trailing edge. The (upstream) ends of the two opposing external surfaces of the housing preferably meet the leading edge at a respective nozzle.

The housing may have in cross-section, in a width direction being perpendicular to the longitudinal direction, the general profile of an aerofoil. The characteristic shape of an aerofoil has a rounded (curved) leading edge, followed by a substantially sharp trailing edge, and may have a substantially symmetric curvature of upper and lower surfaces. In one embodiment, the opposing nozzles are arranged adjacent the leading edge of the housing and may be located at opposing longitudinally-extending ends of the leading edge.

Preferably the nozzles are elongate nozzles and/or form an elongate array of nozzles, in which array the individual nozzles may be elongate or non-elongate in shape.

The nozzles preferably extend substantially in the longitudinal direction of the housing.

In a preferred embodiment, the nozzles are substantially linear and/or form a substantially linear array. However, the nozzles may be non-linear or curvilinear; for example, the nozzles may each have a wave-shape, a U-shape or a C-shape or form either a wave-shaped, a U-shaped or a C-shaped array.

The housing preferably has a coanda surface provided by the trailing edge and a region adjacent thereto. The trailing edge and this adjacent region are herein termed 'the trailing edge region'. The region adjacent the trailing edge is preferably at least part of one of the two opposing external surfaces. In addition or alternatively, the trailing edge region may have a beaked profile or a round head profile. In a preferred embodiment, the profile of the trailing edge is sharper than the profile of the leading edge. Preferably the trailing edge is a substantially sharp edge. Preferably the leading edge is a substantially rounded edge. If the trailing edge is also a substantially rounded edge (when it has a round head profile), then it preferably has a smaller radius of curvature than that of the leading edge.

A coanda surface is a convex surface which provides a coanda effect. The coanda effect is the tendency of a fluid jet to be attached to a nearby surface.

The trailing edge is preferably spaced from the nozzles by the opposing external surfaces of the housing. As such, the coanda surface is spaced from the nozzles by the opposing external surfaces of the housing.

The depth of the trailing edge region, when viewed in cross section in the width direction through the air mass induction device, is preferably smaller than the depth of the leading edge, when viewed in cross section in the width direction.

The internal chamber of the housing, in cross-section, is preferably substantially symmetrical about an axis extending in the width direction of the housing, the width direction being perpendicular to the longitudinal direction. This shape is beneficial but not essential: it enables the air pressure at the nozzles to be approximately the same at both opposing external surfaces of the housing, therefore discharging air at approximately the same flow rate over both opposing external surfaces of the housing.

In one example, the trailing edge region may have a turning angle of about 0 to 90° from the axis of symmetry of the internal chamber in the width direction. In another example, the trailing edge region may have a turning angle of about 0 to 10° from the axis of symmetry of the internal chamber in the width direction. This turning angle may be adjustable during use, for example by providing a pivot point along the trailing edge region such that it is rotatable about its length (being substantially in the longitudinal direction of the housing) relative to the main body of the housing.

The housing is preferably substantially symmetrical about a plane of symmetry located at a central position of the housing in the longitudinal direction. At least one air inlet may be provided: one or more air inlets may be provided at a central position or another position of the housing in the longitudinal direction. In one embodiment, multiple air inlets are provided.

In one embodiment, the housing defines a pair of wings, each wing extending in a longitudinal direction from either a central position or another position of the housing in the longitudinal direction. In another embodiment, the housing defines a single wing extending from one end of the housing.

The housing may comprise opposing internal surface edges, each located adjacent at least one nozzle, with each of the opposing internal surface edges being tear-drop shaped. The opposing internal surface edges preferably protrude into the internal 15 chamber.

In a preferred embodiment, the housing comprises a first portion, a second portion and a third portion, wherein the first portion comprises the leading edge, the second portion comprises at least a part of the two opposing external surfaces and the third portion comprises the trailing edge. These portions, or sub-portions thereof, may be formed separately and joined together, as appropriate, or they may be formed in one or more integral pieces. Thus, for example, the second portion and the third portion may be formed in a single piece, or alternatively, they may be formed in more than two pieces. Also, the first, second and third portions may be formed as a single piece.

At least part of the second portion and at least part of the third portion preferably define the two opposing external surfaces. The second portion and the third portion may, either individually or together, be formed as a single body piece or as two or more distinct pieces which are co-joined during manufacture or assembly. Preferably, the third portion is strengthened relative to the second portion and/or to the first portion.

The first portion and the second portion of the housing preferably define the internal chamber. In this respect, the second portion may be vessel-shaped in cross-section in the direction of the width of the housing. The first portion may have a curved form, at least in part, and an interior, concave surface of the first portion, together with the interior of the second portion, may define the internal chamber.

Preferably, the nozzles are defined between the first portion and the second portion. The first portion and the second portion may be intermittently joined to form and/or to maintain the shape of the nozzles.

In a preferred embodiment, the second portion has a maximum external depth which is less than the maximum internal depth of the first portion, such that the upstream end of the second portion fits within the downstream end of the first portion, at least in part, thereby forming the nozzles and defining the internal chamber. In this respect, the depth direction is perpendicular to both the width direction and the longitudinal direction of the housing.

At the upstream end of the second portion, the second portion may be formed with the opposing internal surface edges.

The first portion may be formed with extended, opposing surfaces which overlay, whilst being spaced from, the two opposing external surfaces of the second portion. This provides an air channel for directing air from the nozzles towards the trailing edge.

The air mass induction device may be pivotally mounted to control its tilt angle and thus the directions of the flows of air.

The present invention also provides a method for air ventilation using the air mass induction device, the method comprising the following steps: a) creating an air flow; b) directing the air flow into the housing, wherein the air flow leaves the housing via the nozzles; c) receiving the air flow from the nozzles on the opposing external surfaces of the housing, thereby inducing air from outside the housing to flow in the direction of the trailing edge; and d) receiving the air flows at the trailing edge for onward motion.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a cross-sectional view in a width direction through the air mass induction device according to a first embodiment of the invention; Figure 2 is a front perspective view of the induction device of the first embodiment; Figure 3 is a rear perspective view of the induction device of the first embodiment; Figure 4 is a perspective view from beneath the induction device of the first embodiment; Figure 5 is a rear perspective view of the induction device of the first embodiment; Figure 6 is a side perspective view of the induction device of the first embodiment; Figure 7 is an exploded view of the induction device of the first embodiment; Figure 8 a cross-sectional, perspective view of the induction device of the first embodiment; Figure 9 is a perspective view of non-assembled portions of the induction device, in part; Figure 10 is a perspective view of assembled portions of the induction device, in part; Figure 11 is a schematic view of the effect that the induction device of the first embodiment has on surrounding air; Figure 12 is a cross-sectional view in a width direction through an air mass induction device according to a second embodiment of the invention; Figures 13a and 13b are cross-sectional views in a width direction through the air mass induction device according to the first and second embodiments of the invention, showing the angle between the two opposing external surfaces at the trailing edge; Figure 14 is a perspective view of assembled portions of the induction device of the second embodiment, in part; and Figures 15a to 15c are perspective views of further embodiments of the invention.

Referring to Figure 1, the air mass induction device has a housing 2. The housing has a leading edge 4 and a trailing edge 6, these edges extending in the longitudinal direction, as shown in Figures 2 to 6.

The housing comprises two opposing external surfaces 8a and 8b which taper towards, and meet at, the trailing edge 6.

In the present embodiment, the opposing external surfaces of the housing are substantially planar, although they may have some degree of curvature.

The housing is preferably elongate, although it may be that the width of the housing (ie the direction from the leading edge to the trailing edge) is longer than the length of the housing.

The housing is linear in shape in the present embodiment, although the invention is not limited thereto. Instead, as shown in Figures 15a to 15c, the housing may have a wave-shape or a curved shape, at least in part, whilst still extending substantially in the longitudinal direction of the housing.

In Figures 15a to 15c, the leading edge and the trailing edge extend substantially in the longitudinal direction of the housing. In Figure 15a, the leading edge is straight and the trailing edge is curvilinear. In Figure 15b, the leading edge is straight and the trailing edge undulates and has a wave-shape. In Figure 15c, the trailing edge is straight and the leading edge is curvilinear. The leading edge may have the same shape as the trailing edge or it may have a different shape to the trailing edge.

In the figures, the housing is shown in a horizontal orientation; however it may be used in other orientations, such as a vertical orientation. The present embodiment is designed for mounting on a ceiling, although it may be mounted on a wall or a floor or a pedestal, for example.

In the present embodiment, the housing has, in cross-section in the width direction, the general profile of an aerofoil, with the nozzles 10a and 10b extending adjacent the leading edge 4. However, the housing may have alternative profile shapes in cross-section in the width direction.

Located adjacent each opposing external surface 8a and 8b is a nozzle 10a and 10b, respectively. At least two linear nozzles or at least two linear arrays of nozzles extend in the longitudinal direction of the housing in this embodiment. At least one nozzle is arranged to direct air received from within the housing over the respective opposing external surface towards the trailing edge, to induce air from outside the housing to flow in the direction of the trailing edge. This induction effect is explained in more detail below (with reference to Figure 11).

The nozzles in the present embodiment are linear. However, the nozzles may be non-linear or curvilinear. It is preferable that the nozzles are at least elongate in shape or form an elongate array of nozzles, given the preferred elongate shape of the housing. Moreover, it is possible for nozzles or other openings to be provided on outer surfaces of the housing other than the opposing external surfaces 8a and 8b.

Each nozzle is in fluid communication with at least one internal chamber 12 which is provided in the housing. The housing also has at least one air inlet 14 (shown in Figures 7 and 8) which is also in fluid communication with at least one internal chamber. In the present embodiment, the internal chamber is located between the air inlet 14 and the nozzles 10a and 10b and the incoming air is circulated within the internal chamber before exiting through the nozzles. In another embodiment, two or more internal chambers are provided, which may or may not be in fluid communication with each other, depending in part on the location and the number of air inlets and nozzles provided. For example, when the housing is in a horizontal orientation as shown in the figures, it may comprise a plurality of internal chambers situated side by side in the longitudinal direction; alternatively, in this horizontal orientation, the housing may comprise a plurality of internal chambers situated side by side in the depth direction (for example, being upper and lower internal chambers, each being in fluid communication with an opposing nozzle).

The internal chamber 12 of the housing, in cross-section in the width direction, is substantially symmetrical about an axis extending in the width direction of the housing, the width direction being perpendicular to the longitudinal direction. Alternatively, the internal chamber 12 of the housing, in cross-section, is non-symmetrical about an axis extending in the width direction of the housing. However, it is preferred that the cross-sectional shape of the internal chamber is substantially symmetrical because this shape enables the air pressure at the two opposing nozzles 10a and 10b to be approximately the same and therefore the nozzles can discharge air at approximately the same flow rate.

An internal chamber, being substantially symmetrical in cross-section in the width direction, also minimises the pressure required to cause the air to flow and maximises the air flow. The size of the internal chamber may be optimised for a static regain on pressure.

The opposing external surfaces 8a and 8b taper towards the trailing edge 6 which is located downstream of the opposing external surfaces and remote from the nozzles: the opposing external surfaces are located between the nozzles and the trailing edge.

The housing preferably has a coanda surface provided by the trailing edge and a region adjacent thereto being at least part of one of the two opposing external surfaces; the trailing edge and this adjacent region are herein termed 'the trailing edge region'. In addition or alternatively, the trailing edge region may have a beaked profile or a round head profile.

A coanda surface is a convex surface which provides a coanda effect. The coanda effect is the tendency of a fluid jet to be attached to a nearby surface. I n the present embodiment, the coanda surface provided by the trailing edge region starts approximately half way down external surface 8a of the housing and then extends downstream to the trailing edge 6.

The trailing edge region acts as a turning tip. The trailing edge region plays an important role in how the air is entrained and reaches the space to be ventilated.

The trailing edge region preferably has a turning angle (angle a as marked on Figure 13a and 13b) which is pre-determined to meet the desired air flow performance. The turning angle of the trailing edge region can be designed during manufacture to achieve optimum performance. In one example, the turning angle of the trailing edge region may be adjustable during use, by, for example, providing a pivot point along the trailing edge region such that it is rotatable about its length relative to the main body of the housing.

The turning angle a is measured between: * a first line extending along the line of symmetry of the internal chamber in the width direction and * a second line extending from a point where the first line meets the leading edge to a point on the trailing edge that is furthest in distance from the point where the first line meets the leading edge.

The angle between the two opposing external surfaces at the trailing edge 6 (angle b as marked on Figure 13a and 13b) is preferably in the range of 30 to 50 degrees. When the trailing edge has a beaked profile, the angle b between the two opposing external surfaces at the trailing edge is preferably in the range of 10 to 70 degrees. When the trailing edge has a round head profile, the angle b between the two opposing external surfaces at the trailing edge is preferably in the range of 10 to 180 degrees. The shape of the trailing edge region is preferably designed to divert the air flows towards the space to be ventilated. The trailing edge region preferably has an optimised profile for directing the air flows it receives. Examples of profiles in the trailing edge region are described below in relation to Figures 13a and 13b.

A trailing edge region with a beaked profile or a round head profile and/or a coanda surface aims to provide the target space with a high air velocity and an even distribution of air flow compared to a trailing edge region which is symmetrical in cross-section about an axis extending in the width direction of the housing.

In the present embodiment, the housing comprises a first portion 16, a second portion 18 and a third portion 20. The first portion comprises the leading edge 4, the second portion comprises part of the two opposing external surfaces 8a and 8b, and the third portion comprises the trailing edge 6 and part of the two opposing external surfaces 8a and 8b. These portions, or sub-portions thereof, may be formed separately and joined together, as appropriate, or they may be formed in one or more integral pieces. In Figure 1 they are shown as four pieces (the second portion is formed of two pieces) which are adapted to be joined together. This is partly for ease of manufacture and transportation.

The wall thicknesses of the different portions are dictated in part by the mounting method and overall dimensions of the induction device. The wall thicknesses of the different portions may be in the region of 1.5 mm to 5 mm. In one example, the wall thicknesses are approximately 2.5 mm. The portions forming the housing of the induction device may be made from moulded plastics or metal, for example. The third portion 20, which includes the trailing edge, is preferably designed to be sufficiently strong at the trailing edge so as to minimise vibration due to acceleration of the air at the trailing edge. The third portion may therefore be strengthened relative to the second portion and/or to the first portion.

The housing of the induction device may be made of any material which is light in weight, strong in strength and preferably weather-proof. For example, it may be aluminium, carbon fibre, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA).

In the present embodiment, the second portion 18 and the third portion 20 define the two opposing external surfaces 8a and 8b.

The first portion 16 and the second portion 18 form an air plenum. Also, the induction device may be connected to a plenum space or be incorporated into a plenum 20 space.

The first portion 16 and the second portion 18 of the housing define the internal chamber 12. In the present embodiment, the second portion is vessel-shaped in cross-section in the width direction and the first portion has a curved form, at least in part, and the internal, concave surface of the first portion, together with the interior of the second portion, define the internal chamber. Therefore, at least the second portion 18 is hollow in order to provide part of the internal chamber: in one example, as shown in the figures, the second portion is formed from co-joined units.

The curved form of the first portion 16 reduces air resistance; this is desirable as the first portion acts as the leading edge of the housing.

The nozzles 10a and 10b are defined between the first portion 16 and the second portion 18. Since the nozzles may extend along the whole length of the housing, supporting members may be present to maintain a consistent nozzle height. In one embodiment, a tenon and mortise design is used with either the mortise 38 or tenon 40 being provided on the first portion of the housing and the other of the mortise 38 or tenon 40 being provided on the second portion of the housing. This is shown in Figures 9 and 10 which are non-assembled and assembled views of the first portion 16 and the second portion 18, in part. Thus the first portion 16 and the second portion 18 may be intermittently joined to form and/or maintain the shape of the nozzles.

The nozzles may have a height of 2 to 5 mm in the depth direction of the housing: in one example, they have a height of 2.5 to 3.5 mm and may be 3 mm in height. This small nozzle height may assist in creating a high speed air flow. In this respect, the depth direction is perpendicular to both the width direction and the longitudinal direction of the housing. The height of the nozzles in the depth direction will depend, in part, on the proportions of the device.

With reference to Figure 11, the second portion 18 may have a maximum external depth D2 which is less than the maximum internal depth D1 of the first portion 16, such that the upstream end of the second portion fits within the downstream end of the first portion, at least in part, thereby forming the nozzles 10a and 10b and defining the internal chamber 12.

The upstream ends of the second portion 18 are formed with opposing internal surface edges 22 in the present embodiment.

The opposing internal surface edges 22 of the present embodiment are each located adjacent at least one of the linear nozzles or at least one of the linear array of nozzles. Each of the opposing internal surface edges 22 is tear-drop shaped, in one example, although other shapes may be used, particularly if the shape is aerodynamic.

The use of an aerodynamic shape seeks to minimise the occurrence of air turbulence, reduce air resistance and reduce any drop in pressure, as air flows through the internal chamber and through the nozzles. The opposing internal surface edges 22 preferably protrude into the internal chamber 12, as shown in Figure 1.

The first portion 16 provides a longitudinally extending end piece to the housing and acts as leading edge 4. In the first embodiment, the ends 44 of the first portion define outer walls of the nozzles 10a and 10b. These ends 44 of the first portion are approximately adjacent to the opposing internal surface edges 22 of the second portion.

The housing is preferably substantially symmetrical about a plane of symmetry located at a central position of the housing in the longitudinal direction. At least one air inlet 14 may be provided at the central position or another position of the housing in the longitudinal direction and this air inlet may be in fluid communication with a connection chamber 36 located within the housing, as shown in Figure 8. However, it is not essential that the air inlet is provided at this central position since air inlets may be positioned elsewhere in the housing instead of, or in addition to, this centrally-positioned air inlet.

A connector portion 24 may be provided at the central position or another position of the housing. This connector portion, together with optional end brackets 26, may be affixed to a ceiling, for example. The connector portion 24 is preferably in fluid communication with the air inlet 14 to provide air into the induction device housing. The connector portion may comprise or contain an air supply duct to connect to the air inlet 14; the connector portion 24 is preferably designed to conceal the duct, which may be a flexible air duct, to improve the appearance of the device. The connector portion 24 is preferably aerodynamic in shape to reduce air resistance, as shown in Figures 3 and 5.

With reference to Figure 6, the housing has opposing ends 30a and 30b spaced apart in the longitudinal direction; these ends may define walls for the internal chamber. The opposing ends 30a and 30b may include adjustable pivots locks 32 connected to the end brackets 26 to provide adjustability to the induction device. These adjustable pivot locks, provided at each end of the device, control its tilt angle and thus the directions of the flows of air. The invention is not to be limited to the presence of adjustable pivot locks as it is not essential that the device is adjustable in this way. Also, other means for providing adjustment of the device may be readily envisaged, if desired: these means may or may not be provided at each end of the device. In one example, the device is adjusted by altering the angle of installation of the device.

In the present embodiment, the housing 2 defines a pair of wings 34a and 34b, as shown in Figure 2, each wing extending in a longitudinal direction from the central position of the housing in the longitudinal direction. The ends of the wing remote from the central position may be supported by end brackets 26 in use.

Each wing houses at least one internal chamber 12 or other means for delivering air to the nozzles; the internal chamber in one wing may be unitary with an internal chamber in the other wing, thereby forming a single internal chamber; alternatively, their respective internal chamber or chambers may be separate from one another such that they are not in fluid communication. In the present embodiment, the respective internal chamber or chambers of each wing are not directly in fluid communication with each other as the connection chamber 36 is provided therebetween. However, air is able to flow from the connection chamber into the internal chamber or chambers housed within each wing.

Preferably the design of the internal chamber(s) in one wing is substantially symmetrical with the design of the internal chamber(s) in the other wing about a plane of symmetry extending in the width direction and located at a central position of the housing in the longitudinal direction; this facilitates an equalised pressure of the air inside the housing. The preferred symmetrical design of the internal chambers seeks to ensure equal air flow to each nozzle or nozzles adjacent opposing external surfaces of the housing.

The wings 34a and 34b of the housing are preferably linear or curvilinear in shape. It is preferred that the wings are equal in length to ensure even volumetric flow over the two opposing external surfaces of the housing.

Figure 7 shows the device in an exploded state, with the elements forming the device being non-assembled. This is one example of how to make an induction device according to the present invention.

The elements of the induction device, as shown in the exploded figure, are preferably designed to interlock for air tightness. In one example, the elements forming the second portion 18 are joined and then the third portion 20 is slidably connected to the second portion: the first portion 16 is joined to the second portion 18 using the mortise 38 and tenon 40 fittings to form and enclose the internal chamber 12 and to form the nozzles: the opposing ends 30a and 30b are connected to the first, second and third portions, preferably using a plug or snap action: the brackets 26 are fixed to the opposing ends using pins for pivotal adjustment. It can be appreciated that the induction device is relatively straightforward to manufacture and assemble, with no integral mechanical or electrical parts.

Referring to Figure 4, it can be seen that each wing is provided with a linear nozzle 10a and a linear nozzle 10b (the mortise and tenon fittings being located within each of the linear nozzles). These linear nozzles are interrupted at the central position of the housing by the air inlet 14 and the connector portion 24.

To use the air mass induction device, an air flow is created. The air flow is preferably created at a location remote from the induction device, such that the air flow is transported, for example by ducting, to the induction device. The air may be cooled or heated before entering the induction device, or it may be at ambient temperature with a cooling effect being achieved by the induction device simply by air agitation.

By way of example, the induction device may be connected to an air conditioning system, to an air heating system or to an air ventilation system. In one example, it is connected to a simple mechanical ventilation system, with or without the presence of heating coils or cooling coils. Alternatively, the induction device may be attached directly or indirectly to a means for creating an airflow, such as an impeller, a fan or a centrifugal fan (eg an in-line axial fan). However, it is preferred that the induction device is a passive unit, such that it has no integral or integrated means for creating an airflow.

In one example, a flow of air is supplied through a flexible supply duct through the connector portion 24 to the air inlet 14. From here, the air is directed through the connection chamber 36 into the two wings 34a and 34b, each having an internal chamber 12 being unitary with each other and the connection chamber 36. The air is then emitted through the linear nozzles 10a and 10b provided on opposing faces of the housing.

With reference to Figure 11, high speed air jets B and C are emitted over the two opposing external surfaces 8a and 8b of the induction device. The air being discharged through the nozzles from within the induction device may have a velocity of about 5 to 20 m/s or about 5 to 15 m/s; the velocity will depend on part on the proportions of the device. These high speed air jets drag surrounding air to create a larger volume of air flow (see surrounding air flows A and D).

The trailing edge region acts as a coanda surface and diverts air in a downward direction in the present embodiments. It can be readily envisaged that the shape of the trailing edge region in the present embodiments could be inverted such that the trailing edge region instead directs the air upwards or straight ahead, as desired. If the device is oriented differently to that exemplified, or if it has a non-linear form, for example, then the effect of the coanda surface on the air flows will produce different results in terms of the direction of air flow, air velocity, level of air mass induction etc. The induction device may be automatically or manually controlled. For example, the induction device may be controlled by a simple manual ON/OFF switch. Alternatively, it may be controlled automatically by a temperature sensor or a wind speed sensor, using direct digital control. Another alternative is to use a programmable logic control or a building management system. Wireless control, for example using Wi-Fi, is also possible.

The following variables may be adjusted to achieve the most desirable performance of the induction device to enhance user comfort: air speed; air flow rate; pattern (eg sinuousal); and direction.

The induction device is useful in indoor and outdoor spaces where air movement is a concern: an increased airflow provides a better sensation temperature and environment.

Uses of the induction device include: semi-outdoor areas, for example, dining areas outside cafés and restaurants; semi-enclosed car parks; platforms or subways of railway stations and underground stations; bus stops; ticket offices and other entrances where queues may develop. When it has a substantially planar-shape, the induction device may also act as an external shading area.

The induction device is readily integrated with existing buildings. It is lightweight and minimises headroom obstruction. Since there are no visible mechanical parts, it is safe to use with no mechanical noise and little maintenance is required.

Preferably, the induction device is designed to achieve substantially balanced air pressures in the air flows emanating from the opposing nozzles 10a and 10b. When these two, balanced, opposing air streams meet at the trailing edge 6, the resulting combined air stream is channelled in a predetermined direction by the trailing edge. The trailing edge region is preferably asymmetrical in order to provide improved air flow. For example, when the induction device is horizontally mounted, the trailing edge may point downwards, thereby directing the combined air stream downwards into the space to be ventilated.

In use, the air flows directed over the two opposing external surfaces of the housing interact with surrounding air and can drive the surrounding air to achieve high flow rates. The induction device therefore induces a high volume of air flow. This is energy efficient and provides a large coverage area.

The laminar or less turbulent flow characteristics at the nozzles of the induction device result in less airborne noise generation. The nozzles may provide an enlarged blade shape: this provides a two dimensional uni-direction airflow pattern.

The induction device is designed to consume less electricity whilst delivering an amplified performance through its advanced aerodynamic design.

In this respect, an amplification factor is defined as the ratio of a ventilation rate over a supply flow rate. Using the present invention, an amplification factor of 3 or above may be achieved. Indeed, since the high velocity airflow provides an air amplification effect, the amplification factor may be as high as ten.

In one example of use of the device of the present invention, it is desired to ventilate a space which is about 1.7 m above floor level. In order to divert the air flow towards the target space, the trailing edge region may have a turning angle a of about 0 to 10° from the line of symmetry of the internal chamber in the width direction. As a result, an amplification factor of about 9 may be achieved.

In the second embodiment of the invention, as shown in Figure 12, the first portion 16 is formed with extended, opposing external surfaces 46 which overlay, whilst being spaced from, the two opposing external surfaces 8a and 8b of the second portion 18. This provides air channels from the nozzles 10a and 10b in the direction of the trailing edge 6. Thus, the extended, opposing external surfaces 46 of the first portion define outer walls of the nozzles 10a and 10b and also the air channels, but the ends of the first portion are not adjacent to the opposing internal surface edges 22 of the second portion.

As in the first embodiment of the invention, the nozzles 10a and 10b are defined between the first portion 16 and the second portion 18. Since the nozzles may extend along the whole length of the housing, supporting members may be present to maintain a consistent nozzle height. In the second embodiment, the supporting members are elongate spacers 42 located between the extended, opposing external surfaces 46 of the first portion and the two opposing external surfaces 8a and 8b of the second portion 18. This is shown in Figure 14. Thus the first portion 16 and the second portion 18 may be intermittently joined to form and/or maintain the shape of the nozzles.

The other features of the second embodiment are generally the same as, or correspond to, those of the first embodiment and so are not discussed in detail.

Referring to Figures 6, 13a and 13b, these show dimensions of the two embodiments of the invention, where W refers to the width direction and L refers to the longitudinal direction of the device.

Figure 6 also shows angle C which is a possible installation angle for the device, as measured relative to vertically-oriented bracket 26. It can be appreciated that the angle of orientation of the device along an axis extending in the width direction of the housing, relative to the bracket, about pivot lock 32, is approximately 90 degrees in this figure. The pivot lock is adjustable such that angle C may be in the range of 45 to 135 degrees from the vertical axis defined by bracket 26. The invention is not limited to these angles. Moreover, the device may not be mounted by vertically-oriented brackets (or by any brackets).

The table below sets out examples of dimensions of small scale and large scale devices in accordance with the first and second embodiments of the present invention, as shown in Figures 13a and 13b.

Small Scale Large Scale Length lm to 3m 5m to 10m Width 300mm to 600mm 1m to 2m Volume of internal 6L to 75L 350L to 2850L chamber(s) Angle a 0° to 10° 0° to 10° (turning angle of the trailing edge region) Angle b 10 to 70° or 10 to 70° or (the angle between the two 30° to 50° 30° to 50° opposing external surfaces at the trailing edge) Device Application Example Cafe Area Tunnel, Underground platform It can be appreciated that, generally-speaking, an air mass induction unit for internal use has smaller dimensions than an air mass induction unit for external use. The potential dimensions of the device will vary across a large range depending on the scale and application of the device, for example.

Both embodiments of the invention provide that the air flowing through the nozzles maintains a laminar characteristic or minimises turbulence. The air gap provided at the nozzles is preferably designed to minimise air turbulence and is therefore based on laminar flow characteristics and/or less turbulence and/or discharged velocities.

The induction device of the present invention may replace conventionally used industrial fans or standard air conditioning units; it may serve a larger coverage area using a lower flow rate, whilst providing a more uniform air distribution and whilst reducing dead spots.

Claims

Claims 1. An air mass induction device comprising a housing having a leading edge and a trailing edge each extending substantially in the longitudinal direction of the housing, the housing comprising: two opposing external surfaces which taper towards the trailing edge; and at least two nozzles; wherein at least one nozzle is associated with each opposing external surface and is arranged to direct air received from within the housing over the respective opposing external surface towards the trailing edge, to induce air from outside the housing to flow in the direction of the trailing edge.
2. An air mass induction device as claimed in Claim 1, wherein the housing comprises at least one internal chamber and each nozzle is in in fluid communication with at least one internal chamber.
3. An air mass induction device as claimed in Claim 1 or Claim 2, wherein the nozzles are arranged adjacent upstream ends of the two opposing external surfaces of the housing and wherein the trailing edge is arranged adjacent downstream ends of the two opposing external surfaces of the housing.
4. An air mass induction device as claimed in any preceding claim, wherein the housing has in cross-section, in a width direction being perpendicular to the longitudinal direction, the general profile of an aerofoil.
5. An air mass induction device as claimed in any preceding claim, wherein the nozzles are elongate nozzles and/or form an elongate array of nozzles.
6. An air mass induction device as claimed in any preceding claim, wherein the nozzles extend substantially in the longitudinal direction of the housing.
7. An air mass induction device as claimed in any preceding claim, wherein the nozzles are substantially linear and/or form a substantially linear array of nozzles.
8. An air mass induction device as claimed in any preceding claim, wherein the opposing external surfaces of the housing are substantially planar.
9. An air mass induction device as claimed in any preceding claim, wherein the trailing edge and a region adjacent thereto form a beaked profile or a round head profile.
10. An air mass induction device as claimed in any preceding claim, wherein the housing has a coanda surface provided by the trailing edge and a region adjacent thereto.
11. An air mass induction device as claimed in any preceding claim, wherein the internal chamber, in cross-section, is substantially symmetrical about an axis extending in the width direction of the housing, the width direction being perpendicular to the longitudinal direction.
12. An air mass induction device as claimed in any preceding claim, wherein the housing is substantially symmetrical about a plane of symmetry located at a central position of the housing in the longitudinal direction.
13. An air mass induction device as claimed in any preceding claim, wherein the housing defines either a pair of wings, each wing extending in a longitudinal direction from a central position or another position of the housing in the longitudinal direction, or a single wing extending in a longitudinal direction from an end of the housing.
14. An air mass induction device as claimed in any preceding claim, wherein at least one air inlet is provided.
15. An air mass induction device as claimed in any preceding claim, wherein the housing comprises opposing internal surface edges each located adjacent at least one nozzle, wherein each of the opposing internal surface edges is tear-drop shaped.
16. An air mass induction device as claimed in any preceding claim, wherein the housing comprises a first portion, a second portion and a third portion, wherein the first portion comprises the leading edge, the second portion comprises at least a part of the two opposing external surfaces and the third portion comprises the trailing edge.
17. An air mass induction device as claimed in Claim 16, wherein the second portion and the third portion define the two opposing external surfaces.
18. An air mass induction device as claimed in Claim 16 or Claim 17, wherein the first portion and the second portion of the housing define the internal chamber.
19. An air mass induction device as claimed in any one of Claims 16 to 18, wherein the nozzles are defined between the first portion and the second portion.
20. A method for air ventilation using the air mass induction device of any preceding claim, comprising the following steps: a) creating an air flow; b) directing the air flow into the housing, wherein the air flow leaves the housing via the nozzles; c) receiving the air flow from the nozzles on the two opposing external surfaces of the housing, thereby inducing air from outside the housing to flow in the direction of the trailing edge; and d) receiving the air flows at the trailing edge for onward motion.
21. An air mass induction device substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.
22. A method for air ventilation substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.