AU742210B2 - Spray assembly - Google Patents

Description

WO 98/17105 PCT/AU97/00704 1 SPRAY ASSEMBLY This invention relates to a spraying assembly which is suitable for market garden spraying, and agricultural row crops such as cotton.

BRIEF DESCRIPTION OF THE PRIOR ART.

The need to spray in rows has already been identified, and some attempts have been made to produce equipment which will satisfactorily spray rows, or between rows, and for example reference may be made to the PCT Application WO 87/01909 in the name of HOMBURG, or its Australian equivalent Application 64021/86, wherein a row of spray nozzles was coupled to a fan, each spray nozzle having a slot-like discharge opening which discharges a flat directed current of air into which spray droplets are injected.

The Australian Application 50424/79 in the name of MOORE and DAWSON indicated a full coverage recirculating sprayer assembly which comprised pressurised liquid carried on a vehicle, a horizontal bar coupled to the vehicle and extending laterally of direction of travel, and solid stream spray nozzles communicating with the pressurised liquid, associated with collector means.

The aforesaid two specifications are the only ones known to the Applicant wherein the sprays could be separated from one another, for example for spraying liquid fertiliser over a crop or weedicide between the rows of a crop.

The Applicant herein has identified a need to combat the overspray problem which exists, wherein for example a row of cabbages could be destroyed if weedicide sprayed between that and an adjacent row was carried by the wind or other means from the target area to the cabbages, or vice versa, the weeds between the rows of cabbages could benefit from overspray of fertiliser. It is common practice to produce a spray which has small sized droplets, even into the micron range, and this spray is very susceptible to any air movement which will cause drift of the spray. Even forward movement of the vehicle on which the spraying apparatus is mounted will cause air movements around the spray head and cause drift or movement of the spray outside the desired area.

It is an object of the present invention to provide a spray head in which drift of the spray outside the desired area is minimised to a satisfactory degree or virtually eliminated.

BRIEF DESCRIPTION OF THE INVENTION According to a first aspect of the present invention, there is provided a spray head including a spray unit within a spray hood, each spray hood having a closed top and an open end, wherein said spray unit delivers a vertical discoid shaped spray and is mounted in a major wall of said spray hood such that the delivered spray material does not contact the inner surface of the spray hood to any degree to minimise droplet formation at the open end of the spray hood, said spray hood preventing the spray material within the hood being influenced by wind or air currents.

e*e• According to a second aspect of the present invention, there is provided a spraying assembly incorporating the spray head of the first aspect of the invention wherein each spray hood is mounted on a horizontal bar attached to a vehicle by a vertical eeeee member with each spray hood being vertically and angularly adjustable on the horizontal bar whereby each spray hood is angularly adjustable with reference to the *j0 direction of travel of the vehicle.

e* WO 98/17105 PCT/AU97/00704 3 BRIEF DESCRIPTION OF THE DRAWINGS.

While the invention need not necessarily include the above mentioned details an embodiment is described hereunder in some further detail with reference to and is illustrated in the accompanying drawings in which: Fig 1 is a view of the spray assembly attached to a vehicle; Fig 2 is a cross-sectional view along the lines 2-2 of Fig. 1; Fig 3 is a side elevation of the portion show in Fig. 2; Fig 4 is an illustration of the spray pattern within a hood; Figs 5, 6 and 7 are illustrations of the various positions of the spray heads; and Fig 8 is another embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT.

In this embodiment a motor vehicle 10 is shown in Fig 1 and is of the type commonly used by market gardeners, being provided with a mounting frame 11, the mounting frame 11 having attached to it a transverse bar 12, which in this embodiment is of square tube cross-sectional shape as illustrated in Fig 2, the transverse bar 12 being attached to mounting frame 11 by means of a mounting bar 13 which is illustrated only in fragmentary end elevation in Fig 2, the transverse bar 12 and the mounting bar 13 being welded together. Fig 3 does not illustrate the transverse bar 12 but it merely serves to illustrate the clamping arrangement for vertical suspension bar Vertical suspension bars 15 each carry a spray head 16, the spray head 16 comprising a spray unit 16(a )contained within a hood 17. The hood 17 contains the nozzle which is fed from a hose 18 (Fig 1 and the lower end of hood 17 terminates in a peripheral skirt 20 as shown in Fig 1.

WO 98/17105 PCT/AU97/00704 4 The spray unit used is preferably a so-called "constant drop applicator" wherein droplet size lies mostly in a small range of sizes, and has a horizontal axis of rotation. The curvature of the hood is sufficient that most droplets will fall to the open mouth of the hood without being intercepted by the hood. Thus the spray unit delivers a spray pattern which is generally of vertical discoid shape, whereby the droplets fall to the target area in a hood having a shape that it has an aspect ratio of at least 3.

Referring now to Figure 4, there is shown in cross section a hood 17 with the spray unit 16(a) positioned in a major wall of the hood. The spray unit is positioned in the hood in a position such that in operation the spray droplets do not contact the sides or walls of the hood but fall from the lower end of the hood. In this way all of the spray may be in the small or micron sized droplet form for most effective coverage. If the spray contacted the wall of the hood, then large ineffective sized drops of the spray material would fall from the lower edge of the hood thus not giving effective coverage and also wasting spray material. The aspect ratio of 3 is a preferred ratio, but it will be realised that this can vary depending on the type of spray unit used. The spray unit delivers a spray pattern which is discoid in shape and if it has a greater or lesser thickness in relation to the diameter of the spray pattern, then the aspect ratio of the hood can vary, it being a requirement that the hood be matched to the discoid spray pattern produced by the spray unit such that the spray produced does not contact the internal walls of the hood. Thus while it is preferred that the aspect ratio be at least 3, it is to be realised that the invention is not to be limited thereto. However, it is within the scope of the invention to provide a trough or the like surrounding the bottom of the hood to catch any droplets falling from the bottom of the hood, which spray then recirculated.

As illustrated, each vertical suspension bar 15 is of circular cross-sectional shape, and is firmly clamped to bar 12 by means of saddles 21, such that the rotational position and height of each hood 17 can be adjusted. As shown best in Figs 5, 6 and 7, the width of a spray pattern can be varied by rotating the hoods 17 about their respective vertical axes and the maximum width of a spray pattern can be equal to or even slightly greater than the width of the hood 17 if the hood 17 lies in the same direction as the transverse bar 12.

However the width can be reduced by rotation, width W2 being the width of the spray pattern in the illustrated embodiment, but this can be reduced down WO 98/17105 PCT/AU97/00704 to width W3 by rotation of the respective hoods 17 about their vertical axes, until the narrow widths of hoods 17 is presented in the direction of travel. The width W2 is an intermediate width which can of course be varied by rotation of the hoods.

In an alternative construction as shown in Fig 8, each spray head is mounted by a parallel motion linkage 20 to the bar 12. Each spray head thus trails behind the bar, and includes a wheel 21 supporting the spray head, so the spray head is self levelling as it passes over uneven ground.

Since the spacing between row crops, particularly of vegetables can vary considerably, it is necessary for the spray heads 16 to be positional not only as far as spray pattern width is concerned but also as far the spacing between spray patterns, and this is achieved by means of the clamping arrangements which are shown more particularly in Figs 2 and 3. Saddles 21 are clamped by clamping bolts 24 which terminate at two ends in male threads 25, the bolts 24 extending over the top of and being supported by the upper wall 26 of the rectangular section transverse bar 12, and on the sides of the bar 12 opposite the vertical suspension bars 15, the clamping bolts 24 are provided with return portions 27 which extend part distance across the rear wall 28 of the bar 12 to bear against that wall upon tightening of nuts 29 on the threaded ends 25 of the bolts 24.U-shaped locating strips 33 locate the bolts 24, and the front flanges 34 extend across the outer surface of the front wall 35 of transverse bar 12. The flanges of saddles 21 then bear against the front flanges 34 of the locating strips 33 to thereby clamp the flanges firmly against those strips and at the same time clamp portion of the surface of each respective transverse bar 12 against the front wall In some instances there may be a slight incline to the land on which the spray heads need to operate, and therefore in some instances there are provided curved slots 38 in the flanges of the saddles 21, as best seen in Fig 3.

This is clearly an optional extra.

A consideration of the above embodiment will indicate a number of things: WO-98/17105 PCT/AU97/00704 6 The hoods effectively shield the spray from any undesirable air currents, such as wind or that caused by the forward movement of the vehicle on which the spray assembly is mounted.

The number of spray heads 16 is indefinite and can be extended from the three shown up to say twenty in some cases. The height and orientation of the spray hoods 17, and the spacings are all readily variable to position the hoods where required, and in some instances both weedicide and fertiliser can be sprayed in a single pass of the vehicle 10 between row crops. In some instances it may be desirable for each hood to contain a fan but in most instances contemplated at this time, it is preferred not to use a fan so that the danger of overspray is reduced to some degree. It will be clear that the nuts 29 can be clamped over their threads 25 to retain both the orientation and height of each suspension bar 15 and to retain the spacings of the various shrouds 17, so that all adjustment can be achieved, and all this is achieved with the facility of sliding the locating strips 33 along the transverse width of the array of spray heads, without interference of such movement by the mounting bar 13.

Claims (8)

1. A spray head including a spray unit within a spray hood, each spray hood having a closed top and an open end, wherein said spray unit delivers a vertical discoid shaped spray and is mounted in a major wall of said spray hood such that the delivered spray material does not contact the inner surface of the spray hood to any degree to minimise droplet formation at the open end of the spray hood, said spray hood preventing the spray material within the hood being influenced by wind or air currents.

2. A spray head according to claim 1 wherein the spray unit is positioned with its axis substantially horizontal in said major wall of the spray hood.

3. A spray head according to any one of claims 1 or 2, wherein said spray hood 5 5 has an aspect ratio when viewed in plan of at least 3, provided by a pair of opposed major vertical walls joined by a pair of opposed minor vertical walls.

4. A spray head according to any one of claims 1 to 3 wherein an elastomeric skirt is attached to the open end of the spray hood.

5. A spray head according to any one of claims 1 to 4 wherein a trough is S: provided at the open end of said spray hood to collect any droplets of spray material falling from said spray hood, said collected spray material being recirculated.

6. A spraying assembly including at least one spray head as defined in any one of claims 1 to 5 wherein each spray hood is mounted on a horizontal bar attached to a vehicle by a vertical member with each spray hood being vertically and angularly adjustable on the horizontal bar whereby each spray hood is angularly adjustable with reference to the direction of travel of the vehicle.

A spray head substantially as herein described with reference to the a3/ ripanying drawings. 8

8. A spraying assembly substantially as herein described with reference to the accompanying drawings. DATED this 30 th day of October, 2001. ENVIROMIST INDUSTRIES PTY LTD By their Patent Attorneys MADDERNS