GB2057299A

GB2057299A - Spraying apparatus

Info

Publication number: GB2057299A
Application number: GB7929867A
Authority: GB
Original assignee: MICRONAIR AERIAL
Current assignee: MICRONAIR AERIAL
Priority date: 1979-08-29
Filing date: 1979-08-29
Publication date: 1981-04-01
Also published as: NZ193050A; ES8100116A1; AU5614780A; ZA801536B; NL8004843A; IT1132570B; GB2057299B; FR2464101A1; PT71751A; IT8024332A0; ES489377A0; BR8002315A; AU538772B2; IN152956B; FR2464101B1; PT71751B

Abstract

Spraying apparatus comprising a rotary atomiser including a rotatable atomising element 22, and an axial fan 23 coupled to the rotatable atomising element 22 to form a unitary structure therewith, the axial fan being situated within a cowl 26 shaped aerodynamically to control a blast of air generated by the axial fan whereby, in use, the blast of air from the fan passes over the rotary atomiser to disperse the droplets produced thereby. The rotary atomiser comprises a fixed tubular spindle 21 for receiving the liquid to be sprayed and the rotatable atomising element 22 comprises a hollow gauze cylinder rotatably mounted on the spindle, liquid flowing from the tubular spindle into the interior of the foraminous atomising cylinder. A plurality of such apparatuses is adjustably mounted on a foldable boom carried by a tractor (Figures 3, 5, not shown). <IMAGE>

Description

SPECIFICATION Spraying apparatus This invention is concerned with spraying apparatus.

More particularly it relates to apparatus for distributing liquids and has application to the distribution of chemical aids to crops.

The application of chemical liquids to crops from aircraft by a rotary atomiser has been disclosed by E.J. Bals and F.R.J. Britten in British Patent Specifica tion No. 860819. In the method described in that specification the blast of air produced by the movement of the aircraft through the air is an essential part of the method of distribution of the chemicals being sprayed. When, however, a rotary atomiser is mounted on the ground or, for example, on a farm tractor, such a blast of air is absent. The invention sets out to provide spraying apparatus, suitable for use on the ground, which can operate in similar fashion to the above-mentioned airborne apparatus.

According to the invention there is provided spraying apparatus comprising a rotary atomiser including a rotatable atomising element, and an axial fan coupled to the rotatable atomising element to form a unitary structure therewith, the axial fan being situated within a cowl shaped aerodynamically to control a blast of air generated by the axial fan whereby, in use, the blast of air from the fan passes overthe rotary atomiserto disperse the droplets produced thereby.

The rotary atomiser may comprise a fixed tubular spindle for receiving a liquid to be sprayed and having closure means at one end thereof, said rotatable atomising element comprising a hollow foraminous atomising cylinder rotatably and coaxially mounted on the spindle, means being provided to permit flow of liquid from the tubular spindle to the interior of the foraminous atomising cylinder.

There may be provided means to rotate the unitary structure and means to pressurise the liquid delivered to the rotary atomiser, said rotating and pressurising means being arranged so that their relative outputs can be varied.

The unitary structure including the axial fan situated within the cowl and the rotatable atomising element may be attached to and driven by a prime mover, for example an internal combustion engine, to form a free standing unit.

The assembly of the axial fan, the cowl and the rotary atomiser forms a spraying head, and a plurality of spraying heads, together with a container to hold the liquid to be sprayed, may be mounted on a farm tractor or any other type of vehicle. The tractor power take off may be used to rotate the unitary structures and also to pressurise the liquid being sprayed. The power link between the tractor power take off and the unitary structures may include an hydraulic system and a toothed belt.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure lisa sectional side elevation of the spraying apparatus according to the invention, Figure 2 is an end view from the air inlet end of the spraying apparatus illustrated in Figure 1, Figure 3 illustrates a farm tractor, seen from the rear, with a support boom carrying five spraying heads, Figure 4 illustrates the farm tractor with the side portions of the support boom folded upwards and four of the spraying heads turned to spray outwards, and Figure 5 is a sectional enlargement of that part of the support boom shown in the circle A in Figure 3.

Referring to Figure 3, a farm tractor 11 has a support boom 12 attached to the back thereof by means of a conventional three point pick up.

Mounted on the support boom 12 are five spraying heads 13 the construction of which will be described later. The spraying heads 13 are each attached to the support boom 12 by an adjustable support 14 so that the direction in which each spraying head 13 faces may be varied.

Each side portion 15 and 16 of the support boom 12 is attached to the centre portion 17 by angled hinges 18 which allow the side portions 15 and 16 to be folded upwardly as illustrated in Figure 4. When the side portions 15 and 16 are in the upwardly folded position some of the spraying heads 13 may be turned on their adjustable supports 14 to face outwardly and any spraying heads 13 not required may be shut off so that orchards or vineyards may be sprayed. When the side portions 15 and 16 are folded upwardly the overall width of the apparatus is reduced so that its movement from one spraying site to another is simplified.

Referring to Figures 1 and 2, each spraying head 13 has a non-rotating mounting 19 which is carried by a strut 20 supported by the adjustable support 14.

The mounting 19 carries a fixed tubular spindle 21.

The tubular spindle 21 has two anti friction bearings (not shown) which coaxially and rotatably support on the spindle a unitary structure including a cylindrical gauze liquid atomising element 22 and an axial fan 23.

The axial fan 23 has five blades 24 mounted in a split boss 22 the parts of which are held together by bolts and nuts which may be loosened and the parts separated to allow the pitch of the blades 24 to be adjusted.

The axial fan 23 rotates within the downstream end of a cowl 26 shaped aerodynamically to control the air blast generated by the axial fan 23. The cowl 26 is supported, concentric with the axial fan 23, by the strut 20 and the adjustable support 14. To obtain conveniently the double curvature shape of the cowl 26 it is made of glass reinforced plastics.

Chemical fluid to be sprayed enters the fixed tubular spindle 21 through an inlet 27 at its end carried by and passing through the non-rotating mounting 19. The opposite end of the fixed tubular spindle 21 is closed by a spring loaded valve 28 which is opened by the pressure of chemical liquid to allow the liquid to emerge into the inside of the cylindrical gauze liquid atomising element 22.

The chemical liquid is carried in a container 29 (Figure 3) on the farm tractor 11. It is pumped by a standard chemical pump (not shown) to each spraying head 13 by way of flexible and rigid pipes.

One of the rigid pipes 30 is shown in section in Figure 5.

The unitary structure including the cylindrical gauze element 22 and the axial fan 23 is driven by an hydraulic system. An hydraulic reservoir and hydraulic pump are mounted on the farm tractor 11, the hydraulic pump being driven from the tractor power take off. Flexible pipes 31 and rigid pipes 32 convey the pressurised and return hydraulic fluid between the hydraulic pump and an hydraulic motor 33 attached to the non-rotating mounting 19 buy a bracket 34. A toothed drive belt 35 running on sprockets interconnects the hydraulic motor 33 and the unitary structure. The speed of the unitary structure which includes the axial fan 23 may be changed either by altering the output of the hydraulic pump or by changing the size of the sprockets which carry the toothed drive belt 35.

Flexible pipes are included in the pipe runs of both the chemical liquid and hydraulic systems to allow the support boom 12 to befolded and the spraying heads 13 to be turned without disturbing either system.

An advantage of a spraying unit having a rotary atomisation is that an even droplet spectrum is obtained even when extremely low volumes are being sprayed. This, in combination with an air blast to distribute the droplets allows concentrated chemical liquids to be spread evenly resulting in a reduction in volume applied for a given coverage. By providing for the output of the chemical liquid pump to be variabie in relation to the speed of the axial fan the invention allows the volume of liquid being sprayed to be reduced without reducing the strength of the air blast.

The invention is not limited to the application of chemicals to crops. For example a free standing unit having one spraying head may be used in an enclosed space for humidification, fumigation or any other application where a fine and even droplet spectrum by spraying is required.

Claims

1. Spraying apparatus comprising a rotary atomiser including a rotatable atomising element, and an axial fan coupled to the rotatable atomising element to form a unitary structure therewith, the axial fan being situated within a cowl shaped aerodynamically to control a blast of air generated by the axial fan whereby, in use, the blast of air from the fan passes over the rotary atomiser to disperse the droplets produced thereby.

2. Spraying apparatus according to claim 1, wherein the rotary atomiser comprises a fixed tubular spindle for receiving a liquid to be sprayed and having closure means at one end thereof, said rotatable atomising element comprising a hollow foraminous atomising cylinder rotatably and coaxially mounted on the spindle, means being proved to permitflow of liquid from the tubular spindleto the interior of the foraminous atomising cylinder.

3. Spraying apparatus according to claim 1 or claim 2, comprising means to rotate the unitary structure and means to pressurise the liquid delivered to the rotary atomiser.

4. Spraying apparatus according to claim 3, wherein said rotating and pressurising means are arranged so that their relative outputs can be varied.

5. Spraying apparatus according to any of claims 1 to 4, wherein the unitary structure including the axial fan situated within the cowl and the rotatable atomising element is attached to and driven by a prime mover to form a free standing unit.

6. Spraying apparatus according to claims, wherein the prime mover is an internal combustion engine.

7. A vehicle having mounted thereon spraying apparatus according to any of claims 1 to 6, and also having mounted thereon a container to hold the liquid to be sprayed and means to deliver liquid from the container to the rotary atomiser.

8. A vehicle according to claim 7, having mounted thereon a plurality of said spraying apparatuses.

9. A vehicle according to claim 7 or claim 8, wherein the vehicle is an agricultural tractor having a power take off, and wherein the power take off is used to rotate the unitary structure or structures and alsoto pressurise the liquid being sprayed.

10. A vehicle according to claim 9, comprising a power link between the tractor power take off and the unitary structure or structures, which power link includes an hyrauiic system and a toothed belt

11. Spraying apparatus substantially as hereinbefore described with reference to Figure 1 and Figure 2 of the accompanying drawings.

12. Avehicle having spraying apparatus mounted thereon substantially as hereinbefore described with reference to Figures 3,4 and 5 of the accompanying drawings.