WO2003016638A1

WO2003016638A1 - Material collection using airflow

Info

Publication number: WO2003016638A1
Application number: PCT/AU2002/001111
Authority: WO
Inventors: Kevin Ross Inkster
Original assignee: Arbortech Pty Ltd
Current assignee: Arbortech Pty Ltd
Priority date: 2001-08-17
Filing date: 2002-08-19
Publication date: 2003-02-27
Anticipated expiration: 2004-02-17
Also published as: AUPR706701A0

Abstract

An air cushion supported vehicle has circular body (1) on which a user stands holding handle (8) and changing direction by altering his weight distribution. The air used to support the vehicle can also be used to clear large areas of litter, leaves, etc. Motor (3) drives fan (4) to provide the supporting air cushion n plenum chamber (5) which is surrounded by flexible inflatable skirt (2). Turbulent airflow escaping beneath the forward portion of skirt (2) scours particles or liquid off surface (22) and these are fed (assisted by the coanda effect) to peripheral channel (10) and then led, using suction, through passages to cyclonic-type separators on the vehicle.

Description

MATERIAL COLLECTION USING AIRFLOW

TECHNICAL FIELD

This invention relates to material collection including apparatus for this purpose and a method for effecting material collection.

BACKGROUND ART

It is known to collect material of a particulate nature laying on a surface or imbedded within the pores or structure of a surface by use of a vacuum which effects a sucking into a collection passageway.

There has been discovered, in accordance with this invention, an apparatus and method which results in improved effectiveness and efficiency for collection of material where typically vacuum type cleaners have previously been used.

It is an object of this invention then to propose an apparatus and a method which provides for effective collection of material from a surface or, at the least, provides the public with a useful alternative.

DISCLOSURE OF THE INVENTION

In one form of this invention there is proposed a material collector being a body adapted to be passed across a target surface on which surface there is material of a particulate and/or liquid form to be collected, the body having a lowermost part providing a surface for defining between it and the target surface, a gap providing an air passageway, a source of air at a pressure above atmospheric pressure to provide for the passage of air from a first side of the lowermost part to pass through the gap to a second side of the lowermost part the flow rate and size of the gap being such as to effect an entrainment of materials on the surface being encountered and to carry this to the said second side, and at least one passageway including a mouth connected to a means adapted to effect a flow of air into the mouth by effecting a below atmospheric pressure of air within the passageway, said mouth being located so that at least some of the material entrained by the passage of air through the air passageway defined in part by the lowermost part, will be drawn through said mouth into the passageway. In preference there is a relative pressure between the surfaces to close the gap which is adapted to be resisted by expansive pressure from the air passing therethrough

In a further form of this invention there is a material collector with air being directed below a lowermost part of a body which defines between it and a target surface, a gap and has air being driven by a pressure above atmospheric directed so as to collect material as it passes between the respective surfaces by reason of the level of pressure and the size of the gap, and a collection means in a downstream location to collect said material upon exit through the gap.

In preference the height of the gap is a variable distance which is determined by the result of a pressure to close the gap which is resisted by the aerodynamic characteristics of the air flow through the gap providing a gap opening pressure.

In preference the lowermost part is provided by a material that is of a pliable characteristic.

In preference there is a collection area with air below atmospheric pressure on a downstream side whereby to then collect and further transport the material suspended. In preference, the body is supported above the surface, at least in the main, by air at pressure above atmospheric pressure.

In preference, it is further arranged such that the air at above atmospheric pressure effecting support of the body is also the same body of air that is causing exiting of air through the air passageway defined in part by the lowermost part defining a periphery of a plenum.

In preference, the body is adapted to be supported at least in the main by air within a plenum causing the body to hover above the surface with the lowermost part being above the surface by a distance determined by the hover or air cushion effect.

In preference, the lowermost part has a streamline shape for airflow for air passing through the air passageway which is also of advantage at an exiting location where a coanda effect may urge air to follow up and around the skirt shape (it is felt currently that the nature of the air flow especially immediately through the narrowest portion of any gap is at least predominantly turbulent as compared to lamina). In preference, the body is in the form of an air cushion style vehicle.

In preference, the passageway connected to the mouth or mouths directs air being sucked through the mouth into a separator where material entrained is adapted to be separated from the air.

In preference, the body is adapted to be a hover or air cushion type vehicle and the mouth or mouths for collection of air with entrained material is positioned to collect air and subsequently entrained material where this has been blown from beneath the lowermost part defining a gap and which is a forward portion of the periphery of the vehicle.

In a further form, the invention can be said to reside in a method of collecting material where the material is on a surface and is in the form of particulate material and/or liquid, including the steps of having a body with a lowermost part so that the lowermost part defines between it and the surface, an air passageway which is a gap, and effecting passage of air through such gap where the air is at a higher than atmospheric pressure on an upstream side of the gap, and effecting a collection of any materials subsequent to passage through the passageway by effecting a suction through a mouth or mouths in the vicinity of the exiting air from the gap.

In preference, the lowermost part of the body defining the passageway is supported by an air cushioning effect between the body and the surface.

For a better understanding of this invention it will now be described with relation to embodiments which shall now be described with the assistance of drawings wherein:

Figure 1 is a plan view of the embodiment;

Figure 2 is a cross-section along the lines to 2 of the embodiment shown in Figure 1;

Figure 3 is an enlargement of the front portion of the cross-section as shown in Figure 2; and

Figure 4 is a perspective view of the embodiment which is the subject of the preceding Figures 1 , 2 and 3.

Referring to the drawings, there is a body 1 which supports elements appropriate for providing air cushion support including a surrounding peripheral lowermost inflated curtain 2, a motor 3 which drives a fan 4 which then effects a buildup of air pressure within an underneath pressure or plenum area generally shown at 5.

Specifically the inflated curtain 2 is located so as to be fully beneath a periphery of the body 1. The shape in cross section of the curtain 2 when inflated is such as to facilitate passage of the body over obstacles so that where it has a rounded shape this therefore provides a forward taper at a lowermost outer edge. Thus when the body 1 moves against a surface obstacle of modest size, this tapered shape helps the curtain or skirt to ride over this obstacle by assisting in a lifting of that section of the skirt. This skirt shape which provides both for the function of assisting closure against release of the air in the plenum and this tapered shape to assist the ride over effect is provided by a pliable wall that is able to change its shape under some external pressures.

The gap beneath the skirt is therefore defined by the lowermost surface of the curtain or skirt 2. The principle of an air cushion vehicle is that it is lifted by a sufficient pressure of air in its plenum area. A gap beneath the curtain or skirt is effected when the vehicle is in its lifted mobile condition and this implicitly allows for air to release. A discovery of this invention has been that, in the conditions applicable with a lifted air cushion vehicle, that ground defining a lowermost surface of the gap beneath the curtain or skirt is subjected to a very effective scouring with particles and liquids on the ground being caught and transported out from beneath the gap area and in some cases being carried up and around the skirt shape. The extent and efficiency to which this effect occurs is observed to be of a very high order indeed.

An analysis of the possible physics applying here can be of value. The height of the gap is determined by the weight of the vehicle as a whole as applicable to a particular area, the pressure within the plenum chamber and the characteristic of any air flow as it passes beneath the gap. It is known that in the case of streamline flow there will be a Bernoulli suction effect that will cause the adjacent surfaces to be urged together which is also assisted by the weight of the vehicle. However, as any gap gets smaller there is an inevitable result from our understanding of physical phenomenon that the flow will become more turbulent. With turbulent flow (Reynolds number > 1) there will be an outward expansive pressure rather than an inward sucking pressure. Therefore, as the gap gets smaller we can expect a higher degree of turbulence. The observed effect is that the gap size stabilizes where there is a sufficient extent of turbulence that maintains a sufficient degree of outward pressure to keep lifted the vehicle as a whole. However, with a substantial body weight this will mean that the gap will be expected to have a high level of turbulence to provide a sufficient countering lift. (This turbulence also assists in keeping restricted the rate of release of air from the plenum). The effect is observed to be a stable one provided that there are not external effects such as inertia effects or resilient retentions that may set up some vibratory frequency effect. It is felt that the pliable nature of the underneath surface of the curtain of skirt is of assistance here. This effect then is despite a shape in cross section of the skirt that at first sight may facilitate streamline flow of air through the gap. It is thought however that there can be some streamline or lamina flow at an initial entry to the gap but the overall effect is an expansive rather than contractive effect.

What we have then if our theory based upon some observed results is correct, is an effect that implicitly effects a high degree of turbulence immediately adjacent to a surface that we want to have cleaned. Further, the passage of air being turbulent then carries the collected materials to locations where these can be gathered and we have observed that collection is appropriate in various ways that will be described.

The air cushion vehicle being shown in this embodiment illustrates a particular form of air cushion vehicle but it is well recognized that there are a very large number of different varieties of such vehicles now available so that this illustration is given to show one example only and it is clear that many other embodiments are appropriate for this particular invention. The unit being shown in this embodiment has features which are different from many other air cushion vehicles including a rearward drive wheel system at 6 which provides, as desired by reason of balance of orientation of the body 1 , a drive of the vehicle while generally being suspended by an air cushion effected by reason of contact with the ground over which the body is being supported.

In addition in this particular embodiment, there are provided brushes one to each side, these being shown at 7 which are freely rotatable but arranged so that if the body 1 is then tilted so as to bring the brush into contact with the ground, then there will be a resultant retarding influence on the direction of the body 1.

The body 1 also includes an upwardly projecting handle 8 so that a single rider standing on the body 1 somewhat midway from front to back and holding handle 8, can control the forward and sideways direction of the vehicle by altering weight distribution so that one part of the body 1 is lower to the ground surface as compared to another part and as appropriate is therefore caused to contact either the drive wheel 6 or a brush such as at 7.

All of the above description is describing an existing vehicle which is intended to describe a typical hover craft device.

The difference in this case in accordance with this embodiment is that there is located a mouth 10 which is connected to a manifold 11 which leads through conduits such as at 12 and 13 to a source where the pressure is reduced to below atmospheric pressure.

In this embodiment, there are provided turbo separators at 14 and 15 which are arranged to cause suspended particulate materials in any airflow being introduced from passages 12 in the one case or 13 in the other to be spun out and caused to settle and therefore be collected while there is a passageway at 16 in one case and 17 in the other that continues the connection of air below atmospheric pressure into the air intake provided by the fan 4.

The position of the mouth 10 of the manifold 11 is so that it extends from one side at 18 around a front of the body 1 to the other side at 19. Further however, the position shape and size of the mouth and extent of vacuum below atmospheric is chosen so that entrained particles resulting from turbulent flow through the gap will be induced to enter into the mouth. While the drawing illustrates one specific case which gives a best result in one circumstance we have found that it is very helpful to adjust these factors in each case to take account of actual variations. The effect is assisted by a coanda effect where the air and entrained material will have a tendency to follow the outerwall shape of the skirt to a suitably located collection location.

Both of the passageways 12 and 13 connect into the manifold so as to draw air equally from the respective sides so that there is an extension of the suction effect by reason of the air being below atmospheric pressure and therefore sucking from the mouth that is open through this full arc, that is from the location 18 around the front to the location 19.

The location of this mouth 10 is chosen so that particulate material and/or fluid that has been captured within an air stream shown at 20 and being temporarily suspended thereby, will then be caught by the air flow being directed into the mouth 10 and will then be continued to be kept in suspension until being captured by the entry into the respective passageways 12 and 13.

The arrangement then is that there is air at pressure above atmospheric in the plenum area 5 which will effect both by reason of this being above atmospheric pressure and by reason of lifting the vehicle, cause a flow distribution of air including a blast of air at pressure through a gap defined between the ground and a lowermost surface of the skirt 2.

This air being at a pressure above atmospheric, can accordingly be substantially above atmospheric if desired but by reason of this both being directed in the sense of being radially directed out from the body 1 and being caused to flow between the narrow gap defined by a lowermost part of the skirt 2 at 21 and a ground surface at 22, means that the air will be caused to blast with penetrating and effective force through this narrow gap.

The height of this gap to an extent is of course determined by the characteristics of the body 1 and its total hovercraft or cushion vehicle characteristics including the weight that it must indeed lift.

Nonetheless this gap is kept to a relatively narrow dimension by reason of these characteristics and it is this effect that has been observed to cause a very effective action for air above atmospheric pressure being forced through this gap out to the area outside of the plenum and past the skirt.

By placing the mouth of what might be termed a vacuum head but in our case is termed the mouth of a manifold within which the air is kept at a pressure below atmospheric, at this position outside the immediate passageway of exiting air results in particulate materials be they in solid or fluid form while in a suspended form being then simply drawn into the manifold 11 and from then being dealt with.

There are two very significant advantages of this arrangement.

It has been discovered that by using this characteristic of a very narrow gap being defined by a hover cushion effect, results in a very efficient lifting and effecting suspension of particles and/or fluid as this passes over such materials supported on a surface and as has previously been described this is believed to effect a stable but highly turbulent flow that is ideal for lifting particles.

The location of the mouth can be changed to accord with differing circumstances but is arranged so that it will generally collect if not all nonetheless a substantial amount of the material that is caused to be suspended by the air passing beneath the curtain 2.

The dimensions shown are those that are currently thought to be most appropriate but it is well understood that further experiments could make the collection more efficient.

The underneath shape of the skirt at 21 follows an arcuate shape which is convex and this may be expected at first sight to cause a streamline flow effect. However, as has been previously explained it is now reasoned that this is superficial and the effect is in fact that there will be a turbulent effect created.

If the mouth is located only at a respective side of the vehicle, it is found that this can also be useful in that when the body 1 passes across an area, the particles or liquid will be pushed aside and then at the widest extremity of the vehicle, there will be a single collective lifting of this on each side where a collection mouth with pressure below atmospheric can be located to collect these.

While this then describes one embodiment, it is envisaged that this same concept could apply to a number of differing configurations where there is a defined body with air being directed below a lowermost part which defines between it and a surface a gap and that air being driven at a pressure above atmospheric is directed so as to collect material as it passes between the respective surfaces and that there is a collection with air below atmospheric on the outer side whereby to then remove the material suspended.

In a further preferred arrangement a triangular shape of the periphery of the body is desirable because it will can effectively sweep particles to the sides where they can be picked up by collectors at the rear corners. This is a useful configuration especially in industrial applications especially where it can allow for corners to be more usefully accessed. In trials conducted so far and using a comparison of a standard electric leaf blower at the time of writing this specification, whereas such a leaf blower could ordinarily cover an area of about .01 square metres at very low speed, this embodiment was able to collect material of the same character of an area over one hundred times larger in a time that at the least is similar for the leaf blower of a very much lower area.

Applications for this device are envisaged to be especially useful when the collection uses also the hovercraft effect whether this is using forward propulsion from perhaps a propeller or any other form of drive or of course ground engagement wheels as in the embodiment.

Its application to very quickly clean areas such as streets, sporting arenas both of liquid and particles are envisaged to be a very important application considering the very special improvement in efficiency.

Claims

CLAIMS:

1 A material collector including a body adapted to be passed across a target surface on which surface there is expected to be material of a particulate and/or liquid form to be collected, the body having a lowermost part providing a surface for defining between it and the target surface, a gap providing an air passageway, a source of air at a pressure above atmospheric pressure to provide for the passage of air from a first side of the lowermost part to pass through the gap to a second side of the lowermost part the flow rate and size of the gap being such as to effect an entrainment of materials on the surface being encountered and to carry this to the said second side, and at least one passageway including a mouth connected to a means adapted to draw air into the mouth by effecting a below atmospheric pressure of air within the passageway, said mouth being located so that at least some of any material entrained by the passage of air through the air passageway defined in part by the lowermost part, will be drawn through said mouth into the passageway.

2 A material collector as in claim 1 further characterized in that the collector is adapted such that in use there will be a relative pressure between the surfaces to close the gap and an expansive pressure from the air passing therethrough resisting such closing pressure.

3 A material collector with air being directed to between a lowermost part of a body which defines, between it and a target surface, a gap the air being driven by a pressure above atmospheric to lower pressure downstream from an upstream side through the gap so as to collect particulate materials as it passes between the respective surfaces the effect being by reason of characteristics of the air flow established by the level of pressure and height of the gap, and a collection means in a downstream location to collect said collected material from said exiting air upon exit through the gap.

4 A material collector as in any one of the preceding claims where the air passing through the gap is caused to be in turbulent flow.

5 A material collector as in any one of the preceding claims further characterized in that the height of the gap is a distance which is determined by the result of a pressure to close the gap which is resisted by the aerodynamic characteristics of the air flow through the gap providing a gap opening pressure. 6 A material collector as in any one of the preceding claims further characterized in that the lowermost part is provided by a material that is of a pliable characteristic.

7 A material collector as in any one of the preceding claims further characterized in that there is a collection area with air below atmospheric pressure on a downstream side whereby to then collect and further transport the material suspended.

8 A material collector as in any one of the preceding claims further characterized in that the body is supported above the surface, at least in the main, by air at pressure above atmospheric pressure.

9 A material collector as in any one of the preceding claims further characterized in that it is further arranged such that the air at above atmospheric pressure effecting support of the body is also the same body of air that is causing exiting of air through the air passageway defined in part by the lowermost part defining a periphery of a plenum.

10 A material collector as in any one of the preceding claims further characterized in that the body is adapted to be a hover or air cushion type vehicle and the mouth or mouths for collection of air with entrained material is positioned to collect air and subsequently entrained material where this has been blown from beneath the lowermost part and which is a forward portion of the periphery.

1 1 A method of collecting material where the material is on a surface and is in the form of particulate material and/or liquid, including the steps of having a body with a lowermost part so that the lowermost part defines between it and the surface, an air passageway which is a gap, and effecting passage of air through such gap where the air is at a higher than atmospheric pressure on an upstream side of the gap, and effecting a collection of any materials subsequent to passage through the passageway by effecting a suction through a mouth or mouths in the vicinity of the exiting air from the gap.

12 A method as in the immediately preceding claim further characterized in that the lowermost part of the body defining the passageway is supported by an air cushioning effect between the body and the surface.