CN106998661B - Movable irrigator - Google Patents

Abstract

The invention relates to a movable irrigator. More particularly, but not exclusively, the invention relates to a movable irrigator comprising one or more deflectors configured to apply a stabilising force to the irrigator when exposed to incident wind forces.

Description

Movable irrigator

Technical Field

The invention relates to a movable irrigator. More particularly, but not exclusively, the invention relates to a movable irrigator comprising a plurality of deflectors (deflectors) configured to apply a stabilising force to the irrigator when exposed to incident wind forces.

Background

Irrigators are used in agriculture to apply water and/or nutrients to the ground. In a sprinkler-type irrigator, water is applied to a location within the field and distributed through overhead high pressure outlets.

Mobile/wheeled irrigators typically comprise an elongate pipe supported on a wheeled tower along which sprinklers are positioned. These types of irrigators travel along a field to irrigate a surface area of the field. These may be central pivot or linearly moving irrigators.

A problem with such irrigators is that they tend to tip in high winds. This can damage or destroy the irrigator altogether, resulting in loss of time, money and productivity.

Mechanical anchors are used to secure the irrigator against wind. However, when they are anchored to the ground, the irrigators lose their function. Furthermore, it is not always possible to predict when there will be a strong wind. It is time consuming and inconvenient to install such an anchor each time there is a strong wind and to remove it after the wind has passed.

Other solutions with vehicle weight are suggested. However, this may increase the weight of the irrigator to the point of causing structural damage to the irrigator in the event of wind. This can also result in the irrigator sinking into soft ground or making the rollers deeper and deeper over time, reducing productivity.

The wheel base of the irrigator is enlarged to lower its center of gravity, so that the probability of the irrigator tipping over in strong wind can be minimized. However, this has the disadvantage that the enlarged wheel base may prevent the irrigator from being positioned close to a fence, tall crop or other ground obstacle.

It is an object of the present invention to provide an improved irrigator or at least to provide the public with a useful choice.

The reference to any prior art in this specification does not constitute an admission that such prior art forms part of the common general knowledge.

Disclosure of Invention

In a first aspect, the present invention provides a movable irrigator having a wheeled support structure and a plurality of deflectors of such size, distribution and orientation as to impart to said support structure a steady descending force on the upwind side or a steady ascending force on the downwind side when exposed to incident wind forces.

The deflector may be arranged upwind and/or downwind.

Preferably, the one or more baffles are fins.

Preferably, the one or more baffles comprise a flat surface.

Preferably, the one or more baffles are configured to pivot to a position in which they provide reduced lift.

Preferably, the one or more baffles comprise an arcuate surface.

Preferably, the one or more baffles comprise leading edge slats.

Preferably, the one or more baffles comprise two opposing turns at opposite ends of the baffle.

Preferably, the one or more baffles pivot about a vertical axis.

Preferably, the one or more baffles comprise trailing vanes.

Preferably, the one or more deflectors are displaced outwardly from the longitudinal axis of the irrigator

Preferably, the one or more baffles are displaced beyond one or both sides of the support structure.

Preferably, the baffles are symmetrically arranged on both sides of the support structure.

Preferably, one or more deflectors are arranged at or near the wheels of the irrigator.

Preferably, the one or more baffles are vertically elevated relative to the support structure.

Preferably, the irrigator is a center pivot irrigator.

Alternatively, the irrigator is a linear moving irrigator.

Preferably, the baffle has a dihedral.

In another embodiment, the invention provides a deflector for a movable irrigator having a wheeled support structure, wherein the deflector is of a size, shape and orientation to apply a force to the support structure when exposed to incident wind forces.

Drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1a shows a perspective view of a movable irrigator according to an embodiment of the present invention.

Fig. 1b shows a top view of the irrigator of fig. 1 a.

Fig. 2 shows a cross section of a baffle in the form of a fin.

Fig. 3a shows a side view of a support structure of an irrigator according to an embodiment of the invention.

Fig. 3b shows a top view of the support structure of the irrigator of fig. 3 a.

Fig. 4 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 5 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 6 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 7 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 8a shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 8b shows a top view of the embodiment shown in fig. 8 a.

Fig. 9a shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 9b shows a top view of the embodiment shown in fig. 9 a.

Fig. 10a shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 10b shows a top view of the tab shown in fig. 10 a.

Fig. 10c shows a side view of the tab shown in fig. 10 a.

Fig. 11a shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 11b shows a top view of the tab shown in fig. 11 a.

Fig. 11c shows a side view of the tab shown in fig. 11 a.

FIG. 12 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 13a shows a top view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 13b shows a top view of the tab shown in fig. 13 a.

Fig. 13c shows a side view of the blade shown in fig. 13 b.

Fig. 14a shows a top view of a support structure of an irrigator according to another embodiment of the invention.

Fig. 14b shows a top view of the tab shown in fig. 14 a.

Fig. 14c shows a side view of the tab shown in fig. 14 b.

Fig. 14d shows a baffle in the form of a triangular fin.

Fig. 15 shows a side view of a support structure of an irrigator according to an embodiment of the invention.

FIG. 16 shows a side view of a support structure of an irrigator according to another embodiment of the invention.

Detailed Description

FIG. 1a shows a perspective view of a movable irrigator according to an embodiment of the present invention. The irrigator 1 comprises a pipe 2, the pipe 2 being supported by a wheeled support structure and surrounded by a network of trusses 6 and supports 5. In this embodiment, the wheeled support structure comprises an axle 3 and a plurality of towers 4. The tower comprises wheels 8, the wheels 8 being connected to a support 7 supporting the pipeline. The irrigator 1 further comprises a plurality of deflectors 10 supported on supports 9. The deflector will be described in detail below.

The irrigator 1 in the embodiment shown is a centre pivot irrigator which rotates about an axle 3 so that it waters a circular area of radius equal to the length of the irrigator 1.

Although the invention is described with reference to a center pivot irrigator, the invention is not so limited. For example, the invention may also be applied to lateral movement irrigators (also known as linear, side-roller or wheel-line irrigators) or any other suitable type of irrigator. The irrigator may have any suitable length and include any suitable number or configuration of support structures. The invention is particularly applicable to wheeled/mobile irrigators which are designed to move across a field and are not fixed to the ground, as in use.

Flow guide plate

The deflector 10 is configured to have a size, distribution and orientation such that it applies a downward force to the support structure of the irrigator when exposed to incident wind forces. Thus, the deflector 10 serves to reduce drag induced tipping moments (which may cause the irrigator to tip over). Preferably, the deflector 10 is an angled fin that applies a descending force to the support structure when exposed to incident wind forces. The fins are surface configurations that when properly presented to moving air (in this case wind) generate aerodynamic forces. "baffles" include fins and surfaces that may not provide lift. The term "deflector" includes fins and other elements that can apply a stabilizing force to the irrigator when exposed to incident wind.

Term(s) for

For the avoidance of doubt, the following terms are used in this specification, having the following meanings.

Descending force: the downward force generated by the fins when they are arranged with a negative angle of attack to the wind in the horizontal plane.

Lifting force: the upward force generated by the fins when they are arranged at a positive angle of attack to the wind in the horizontal plane.

Dragging: refers to the aerodynamic forces acting on objects in the wind flow and in the direction of the wind. The drag on the airfoils and their supporting structure is a "penalty" for the descent/ascent forces generated by these airfoils.

Chord: the chord of an airfoil is the line passing through the airfoil from the leading edge to the trailing edge. Fig. 2 shows an airfoil having a leading edge 13, a trailing edge 14 and a chord 12.

Arc-shaped: asymmetry between the top and bottom surfaces of the airfoil.

Dumping moment: the moment of dumping (which can be measured in newton meters) generated by impacting the upper structure of the irrigator.

Angle of attack-Angle between a line drawn through the leading edge 13 and the trailing edge 14 of the wing section and the wind direction in the chord direction FIG. 2 shows an exemplary airfoil disposed at an angle of attack α.

Lifting coefficient: measurement of airfoil lift (lift or droop) per unit area

Aspect ratio: the area of the airfoil plane divided by its span.

Wing attack angle

Preferably, the fins 10 are angled to generate a descending force on the upwind side of the irrigator 1 and an ascending force on the downwind side of the irrigator 1.

The efficiency of a vane can be measured by its heave/drag ratio. The heave/drag ratio of a foil is the strongest function of the angle of attack of the foil. Lower angles of attack generally result in greater airfoil efficiency, but this also provides a lower lift coefficient.

In particular, sometimes strong winds may have a substantial vertical velocity component. In these cases, a wing with a low angle of attack (with reference to the horizontal plane) may experience a transient angle of attack reversal and generate lift when needed to provide a descent force, and vice versa.

Accordingly, it may be desirable for the airfoil of the present invention to have an angle of attack toward the upper end of its useful range of angles of attack. Preferably, the baffles of the present invention will have an angle of attack of 15 to 20 degrees, however the present invention is not so limited.

As will be discussed later in this specification, other airfoil features such as leading edge slats, arcs, and multiple planes may be used to achieve higher lift coefficients associated with higher angles of attack while maintaining acceptable lift/drag ratios.

Aspect ratio

Preferably, the fins 10 will have an optimized size/aspect ratio to prevent the irrigator 1 from tipping over in high winds. Generally, for the same angle of attack, the higher the aspect ratio of the airfoil, the greater the lift it provides relative to towing.

The size/optimal aspect ratio of the fins will depend on the type of fins and other emergency situations (e.g. terrain, type of irrigator, proximity to fences, etc.). For example, a higher aspect ratio may facilitate fixed fins, while a lower aspect ratio may facilitate laterally rotating fins.

Larger and rougher shaped fins can be cheaper and easier to manufacture. A suitable fin aspect ratio for a standard center pivot or linear irrigator may be about 3.

Preferably the baffles/fins will have a chord/thickness ratio of between 2-15%. Thicker fins may result in increased drag.

Configuration of the fins around the irrigator.

Referring back to fig. 1a-1b, baffles are arranged on either side of the irrigator 1.

Preferably, the fins 10 are arranged substantially symmetrically around the irrigator, however in other embodiments the fins may be arranged asymmetrically around the irrigator. If the irrigator (e.g. a linear irrigator) has a constant orientation to the known prevailing strong wind, the deflector may be provided only on the upwind side. This approach is also feasible if the rotary irrigator is able to position the desired azimuth into the strong prevailing wind prior to the high wind event.

The irrigator 1 shown in figures 1a-1b comprises a pivot joint 15 at the connection of the pipe to the tower 4. In many irrigators, the top tube is supported primarily against bending loads in the vertical plane, rather than torsionally. The effect of this is that each span of irrigator 1 between two towers is supported substantially only at three points X. In these models of irrigators, the fins 10 are preferably arranged at or near the wheels of the irrigator, as shown in fig. 1a and 1 b. The flexibility of the irrigator 1 will reduce its effectiveness if the fins 10 are placed elsewhere.

However, it is envisaged that other arrangements of the fins may be suitable in different irrigator models/arrangements.

Wing distance of irrigator

Preferably, the fins 10 are displaced outwardly from the longitudinal axis of the irrigator 1.

Generally, the greater the displacement of the flaps 10 from the center line of the irrigator, the greater the resistance to dumping they will provide with respect to the additional dumping moment (increased dumping moment of drag of the flaps). If the fins 10 are of suitable size and shape, they can generally provide enough torque from ascent and descent to effectively counteract some or even all of the dumping torque (wind force applied to the irrigator 1).

The outwardly displaced tabs may interfere with fences or other obstructions. Even when local space constraints require that the fins remain within the outer dimensions of the wheel base, the fins can still provide some useful dumping mitigation.

In a preferred embodiment, the fins extend over more than one meter past the wheels, however, the invention is not limited thereto.

Height

The optimum height of the fins depends on a number of factors including the type and height of the irrigator, the crop, the terrain, the local wind conditions, etc.

If the wings are too high, their drag (as opposed to the lifting and lowering forces they generate) will unnecessarily increase the total wind induced pitching moment.

If the wings are too close to the ground they will be in the "boundary effect zone" where the wind speed drops significantly compared to the wind speed which at any time will affect the main structure. The fins near the ground may also interfere with the crop and the fence.

In one embodiment of the invention, the fins 10 are about 2.5 meters above the ground. At this height, the fins may be sufficiently far from the reduction of boundary layer velocity to be useful for stabilization, while still benefiting from the smoothing effect of the ground effect (where gusts are unlikely to have a vertical velocity component) and away from most fences and crops.

Material

The baffles/fins may be made of any suitable material. Examples include, but are not limited to, steel, aluminum, fiber reinforced plastic, wood, composite panels, plywood, or any combination of these.

Form(s) of

The deflector may have any form suitable for applying a descending force to the support structure of the irrigator. Fig. 3-6 illustrate irrigators having various forms of deflectors configured to apply a descending force to the support structure of the irrigator.

Fig. 3a and 3b show an embodiment of the irrigator according to the invention in which the deflector has a flat form. The deflector of this embodiment is rectangular and is disposed at an angle of about 30 degrees to the ground. The airfoil 10 provides a downwind side for descent forces and a downwind side for lift forces, which also act to resist the tipping moment.

Fig. 4 shows an embodiment of the irrigator according to the invention in which the deflector has an arc shape. Such an arc-shaped surface increases the upwind force on the upwind side and reduces the upwind force on the downwind side compared to the embodiment shown in fig. 3a and 3 b. This provides a small net increase in the total downforce, promoting constant wheel contact with the ground. In combination with the resulting aerodynamic forces resisting the dumping moment caused by all or at least a useful portion of the total wind, this reduces the likelihood of the irrigator tipping over due to windy conditions.

Fig. 5 shows an embodiment of the irrigator in which the deflector comprises leading edge slats 20. The leading edge slat 20 provides additional descent force and reduced ascent force.

Fig. 6 shows an embodiment of the irrigator in which the baffle includes two opposing turns (i.e. z-shaped surfaces) at the leading and trailing edges of the baffle. This provides additional descent force and additional ascent force.

The baffles may also be in the form of triangular fins as shown in fig. 14 d. Triangular fins may be advantageous due to their high lift coefficient at high angles of attack due to vortex heave.

The deflector may have any other suitable surface shape configured to apply a descending force to the support structure of the irrigator and the invention is not limited thereto.

Multi-planar airfoil

In fig. 3-6, the baffles comprise a single fin form, but may also comprise multi-planar (multi-layer) baffles.

Fig. 7 shows an irrigator in which the deflector comprises three substantially planar forms/planes. Any suitable number of forms may be stacked, however up to four planes are preferred.

Preferably, the distance between the planes is between 20% and 100% of the chord of the airfoil 10.

The multi-planar baffle may include a flat, curved, or z-shaped airfoil shape. The multiple planes may or may not be staggered. Preferably, they are staggered so that the top flaps are closest to the irrigator centerline and the bottom flaps are furthest from the centerline.

Sweepback

In embodiments where the baffles are fins, preferably the fins 10 are swept back. Figures 8-9 show an irrigator including swept back fins (deflectors). The apex of each swept back fin is preferably distal from the irrigator.

Fig. 8a and 8b show chevron-shaped swept wings, while fig. 9a and 9b show curved swept wings. As will be discussed later, the swept-back fins may help to resist longitudinal wind.

Swept-back multi-planar baffles are also contemplated.

Complex angle of attack

Fig. 10 and 11 show deflectors with complex angles of attack.

Fig. 10 a-10 c show two flat foils that can be arranged so that their leading edges are in the horizontal plane, while in the chord direction they present an angle of attack to the wind.

Fig. 11a and 11b show two curved foils that can be arranged such that their leading and trailing edges are in a horizontal plane, while in a chord-wise direction they present an angle of attack to the wind.

Swept-back airfoils with complex angles of attack may provide improved dumping resistance to near-longitudinal wind because their upwind side at least partially eclipses its downwind side.

Further embodiments contemplate similar concepts as curved vanes, vanes with leading edge slats, and multi-planar and/or swept vanes. In addition, the angle of attack may vary in the span-wise direction in a complex manner.

The leading and trailing edges do not necessarily need to be in a horizontal plane.

Fixed wing

As shown in fig. 3-11, the stationary vanes not only provide a descent force on the upwind side, but also generate an ascent force (which also acts to resist the tipping moment) on the downwind side.

It is also possible to provide a wing arranged to exert a falling force on the upwind side and an equal rising force on the downwind side to accurately oppose the tipping moment caused by wind drag.

Move

The airfoil 10 shown in fig. 3-11 has been secured/stationary. However, embodiments are also possible in which the baffles and/or fins are movable.

Figure 12 shows an embodiment of the invention in which the baffle is hinged at the end of the support. The baffle in fig. 12 pivots relative to horizontal axis B1 as indicated by arrow a.

When the tab is exposed to a downward force, the tab is locked down into the position shown in fig. 12. However, when the flap is exposed to an upward force, the flap pivots to the position shown at B1, which prevents the flap from providing lift, or at least reduces any lift.

The relative locking and pivoting positions shown are exemplary, that is, it is also possible to have different degrees of pivoting of the wings resulting in different angles of attack.

In the illustrated embodiment, the hinged flaps have a flat surface, however in other embodiments, the flaps may be curved, lathed, and/or multi-planar.

Fig. 13a shows a top view of another embodiment of the irrigator. The irrigator 1 comprises a deflector configured to pivot on a vertical axis. The wings 10 each comprise a pivot 22 and a tail blade 21 which point the wing 10 across towards the wind direction. This allows the fins 10 (and particularly the upwind fins 10a) to have considerable leverage in resisting wind induced dumping of the irrigator 1. Thus, the rotating wing provides the same lowering force for all wind directions to resist the dumping movement.

FIG. 13b shows a top view of the airfoil shown in FIG. 13a including a blade. Fig. 13c shows a side view of the blade of fig. 13 b. This is only one example of a suitable blade, that is, other suitable blade shapes and/or configurations are possible.

Fig. 14a shows a top view of another embodiment of an irrigator including swept-back vanes that are self-directing without trailing blades. These vanes do not require a trailing blade as the swept back shape of the vane 10 naturally acts as a blade and guides them to a position transverse to the direction of the vane.

For the laterally rotated tabs shown in fig. 13(a-c) -14 (a-c), the lower aspect ratio of the tab 10 would be advantageous as this allows more area to fit into the same available space.

The deflector may also pivot about the center line of the irrigator so that one deflector can stabilize both sides of the irrigator. This would require a strong pivot to support the deflector 3 or 4 metres from the pivot point and could in fact cause the irrigator to tip if the pivot were to jam.

Handling longitudinal wind

As previously mentioned, the fins subjected to longitudinal wind currents with some random vertical velocity components may generate a lift which will undesirably increase the wind induced dumping moment on the irrigator 1.

Fig. 15 shows a side view of a support structure of an irrigator according to an embodiment of the invention comprising fixed fins. Arrow D shows a longitudinal gust of wind which may cause the airfoil 10 to generate an undesirable lifting force, as indicated by arrow E.

In fixed and non-movable foils, a higher aspect ratio may be useful because it reduces the efficiency of the foil 10 when the flow is longitudinal. Thus, when the wind direction is longitudinal to the irrigator 1, their angle of attack is zero, providing neither ascent nor descent, but this may still contribute to the tipping moment when the wind has a significant vertical velocity component. Thus, high aspect ratios may be desirable because when the flow is chordal, the functional aspect ratios are the inverse of their aspect ratios. A vane with such an aspect ratio will produce little, if any, lift and therefore be less likely to tip over when the wind direction is longitudinal (unlike a circular or rectangular vane).

The shapes shown in fig. 10(a-c) and 11(a-c) with complex angles of attack and shadowing effects may help to mitigate longitudinal winds.

Fig. 16 shows a side view of a support structure of an irrigator according to another embodiment of the present invention, comprising fixed fins with a negative dihedron (dihedral) to mitigate the effects of longitudinal wind. Regardless of the direction the longitudinal wind is coming from, when it strikes a foil 10 with spanwise dihedral, the net effect is a downwind force rather than a lifting force, since upwind dumping covers downwind dumping to some extent. The flow will be cleaner and have a higher velocity on the upwind side of the span negative angle of attack, resulting in a downward force on the upwind side greater than the upwind force created by more turbulence and a slower flow on the positive angle of attack 'wake' or downwind side of the airfoil.

In this case, the dihedral may be beneficial for another reason is that the deflection in the main foil support structure may be designed to amplify the excess of the descending force with respect to the ascending force caused by the "wake" effect described above, thereby increasing the negative angle of attack (which produces a downward force) on more of the upwind sides of each foil and reducing the angle of attack (which produces an ascent) on the downwind side of each foil. The torsional stiffness of the mounting structure of each vane can be designed to take advantage of this particular effect (and/or can be pivoted in such a way as to achieve this) with appropriate damping and weight distribution to prevent destructive aerodynamic flutter during the process.

Additional wind protection measures

The basis of the present invention is the use of aerodynamic forces to counteract or at least mitigate the dumping moment generated by the wind impacting the superstructure of the irrigator, an advantageous aspect of the method being that such aerodynamic forces increase with increasing wind speed (by a factor similar to increasing dumping moment).

Under extreme conditions, the use of anchoring (by screws (which may be electrically or hydraulically and automatically activated), piles or weights) to prevent toppling in high winds may still be a necessary back-off option, but with the following disadvantages: at anchoring, the irrigator cannot be used and must be applied in anticipation of and overlapping actual wind events in order to be effectively anchored, and is therefore particularly time and cost inefficient in this regard.

The use of vehicle-mounted weights (for example by water filling the tyres) to mitigate dumping has the disadvantage of making the irrigator more likely to get stuck in soft ground, and can add sufficient load to cause structural failure in the wind, and the load conditions can only be within the permitted range, and in the case of irrigator dumping, it generally seems to worsen the consequent damage. Increasing weight also makes the rim deeper and more damaging to the crop.

Enlarging the base of the irrigator wheel to increase resistance to tipping is a sensible step that certainly would be part of a long term solution, but is undesirable because it requires special manufacturing that purchasers do not require or support in low wind conditions and can also reduce the area around fences, trees, roads and buildings that can be irrigated. Wheel base expanders (e.g., mobile crane type lever arms) have the same problems as anchoring.

Weighting systems that may be used include water tanks mounted at or near each wheel set, which may be statically or automatically filled to weight the irrigator when high wind speeds occur or are anticipated. The progress of the irrigator may stop each time the tanks are filled.

Since the interaction of adjacent spans and destructive snaking increases the stresses at certain locations above what would be expected from average wind loading alone, it is possible to reduce this effect with additional brackets where possible. In particular, raising a set of brackets from each wheel beam to the main support bar at the free end of each span can reduce the useful amount of such twisting and stroking without over stressing the bars and the support frame itself. These brackets may match the brackets from the wheel beam to ensure structure on the fixed side of each tower, but need to have a sliding damping section that moves enough to accept the required length changes to accommodate uneven ground and small deviations from straightness in the top pipe. The damping effect required for effective stabilisation may be around 100kg without itself causing excessive stress in the main rigging.

Advantages of the invention

Accordingly, an improved irrigator is provided which includes baffles/vanes for reducing drag induced tipping moments that may cause the irrigator to tip. This can reduce the likelihood of the irrigator tipping over in high winds, thereby reducing or preventing lost time, money and productivity.

The irrigator is resistant to dumping at all times and therefore if such a strong wind starts, there is no need to anticipate a strong wind or act quickly. There is no need to re-install the mechanical anchor each time there is strong wind and remove it after the wind has passed.

The flaps are configured to effectively resist drag induced tipping moments without the use of weighted irrigators (in this way may cause structural damage to the irrigator or cause it to dig into and become stuck in soft ground or create unnecessarily deep rims).

The fins are at a height that does not interfere with tall crops, fences or other ground obstructions, thereby allowing placement of the irrigator in proximity to such items.

The proposed vane is relatively easy and inexpensive to manufacture.

While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Furthermore, the above-described embodiments may be implemented individually or may be combined where compatible. Other advantages and modifications, including combinations of the above embodiments, will be apparent to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.

Claims (26)

1. A mobile irrigator having: a wheeled support structure; and a plurality of deflectors having a size, distribution and orientation that, when exposed to an incident wind force, applies a steady descending force on the upwind side or a steady ascending force on the downwind side to the support structure.

2. The irrigator of claim 1 wherein, for upwind, the stabilizing force is a descending force on the upwind side.

3. The irrigator of claim 1 or 2 wherein for downwind the stabilising force is a lifting force on the downwind side.

4. The irrigator of claim 1 wherein one or more of the plurality of deflectors are fins.

5. The irrigator of claim 1 wherein one or more of the plurality of deflectors include a flat surface.

6. The irrigator of claim 1 wherein one or more of the plurality of deflectors are pivotable to a position in which they provide reduced lift.

7. The irrigator of claim 1 wherein one or more of the plurality of deflectors include an arcuate surface.

8. The irrigator of claim 1 wherein one or more of the plurality of deflectors include leading edge slats.

9. The irrigator of claim 1 wherein one or more of the plurality of deflectors include two opposing turns at a leading edge and a trailing edge of the deflector.

10. The irrigator of claim 1 wherein one or more of the plurality of deflectors have a swept back fin form.

11. The irrigator of claim 1 wherein one or more of the plurality of deflectors have a triangular fin form.

12. The irrigator of claim 10 or 11 wherein the apex of one or more of the plurality of deflectors is directed away from the irrigator.

13. The irrigator of claim 1 wherein one or more of the plurality of deflectors pivot about a vertical axis.

14. The irrigator of claim 13 wherein one or more of the plurality of deflectors include a tail vane positioned to orient the deflector relative to incident wind.

15. The irrigator of claim 1 wherein one or more of the plurality of deflectors are displaced outwardly from a longitudinal axis of the irrigator.

16. The irrigator of claim 15 wherein one or more of the plurality of deflectors are displaced beyond one or both sides of the support structure.

17. The irrigator of claim 15 wherein one or more pairs of deflectors are disposed on opposite sides of the support structure.

18. The irrigator of claim 17 wherein each pair of deflectors are provided in an up-dihedral arrangement.

19. The irrigator of claim 1 wherein one or more of the plurality of deflectors are located at or near wheels of the irrigator.

20. The irrigator of claim 1 wherein all deflectors are located at or near the wheels of the irrigator.

21. The irrigator of claim 1 wherein one or more of the plurality of deflectors are disposed above wheels of the support structure.

22. The irrigator of claim 15 or claim 16 wherein the one or more deflectors are provided on one side of the support structure.

23. The irrigator of claim 1 wherein each baffle is comprised of a plurality of stacked fins.

24. The irrigator of claim 1 wherein the irrigator is a center pivot irrigator.

25. The irrigator of claim 1 wherein the irrigator is a linear motion irrigator.

26. A deflector suitable for use in the movable irrigator of claim 1, having a size, shape and direction to apply a force to the support structure when exposed to the incident wind force.

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