AU2003248181A1

AU2003248181A1 - A spraying apparatus

Info

Publication number: AU2003248181A1
Application number: AU2003248181A
Authority: AU
Original assignee: Marshall Gregory Gordon; Marshall Penelope Clare
Current assignee: Marshall Gregory Gordon; Marshall Penelope Clare
Priority date: 2002-09-20
Filing date: 2003-09-19
Publication date: 2004-04-08

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE

SPECIFICATION

STANDARD PATENT Invention Title: A SPRAYING APPARATUS Applicant: GREGORY GORDON MARSHALL and PENELOPE CLARE MARSHALL The following statement is a full description of this invention, including the best method of performing it known to me: -2- A Spraying Apparatus Field of the Invention The present invention relates to a spraying apparatus which has particular but not exclusive application in the horticultural and viticulture industries.

Background of the Invention For many horticultural and viticulture crops it is necessary to spray the plant with fertilizers and/or pest control agents. One form of traditional spraying system relies on high-speed air to shear the liquid so as to form fine droplets which are then sprayed over the plant. The problem with this type of system is that a large proportion of the droplets are blown right over the plant. This "over spray" may be unintentionally blown onto other plants that should not have been sprayed, or falls to the ground polluting the soil.

Over spray also greatly increases the amount of liquid being used and thus increases spraying costs.

Another problem with high-speed air spraying systems is that the canopy of the plant has a tendency to close over itself, inhibiting the spray from accessing the interior canopy. Accordingly, the plant does not receive a proper covering of spray on all leaf surfaces.

The present invention seeks to provide an improved spraying system that alleviates at least some of the problems mentioned above with prior art systems.

Summary of the Invention According to the present invention there is provided a spraying apparatus for spraying an object said apparatus including a tank for a liquid, a liquid pump, an air compressor and at least one electrostatic nozzle, said apparatus being arranged to emit charged droplets of the liquid which are attracted to the object to be sprayed.

-3- The charged droplets of liquid are preferably arranged to form a vapour. The droplets of the vapour are preferably sized in the range of 50 60 pjm.

The invention has particular application in the horticultural and viticulture industries where it can be used to spray plants, trees and vines.

In accordance with a preferred embodiment of the invention, the liquid tank includes at least two compartments. One of the compartments of the liquid tank being arranged to receive a first liquid, such as for example a liquid fertilizer or liquid poison, to be sprayed on the plant or vine, and the other compartment being arranged to receive a rinsing fluid such as water, for rinsing the apparatus.

A by-pass arrangement is preferably provided to ensure that the pressure of the liquid flowing in the liquid path and going to the electrostatic nozzle does not exceed a predetermined pressure. Typically, the predetermined pressure of the liquid would be between 15 and 20 psi.

The apparatus is preferably arranged so that the air is passed through an air cleaner before entry into the air compressor. The air compressor may be a rotary or piston compressor.

The air compressor is preferably arranged to pump compressed air through a heat exchanger prior to entry into a manifold. The heat exchanger is arranged to control the temperature of the air so that it is at a preferred temperature for mixing with the liquid to be sprayed. The manifold directs the air into the electrostatic nozzle. In the electrostatic nozzle, the air and liquid are combined in such a way that fine charged droplets of liquid are formed and subsequently disbursed out the nozzle. The droplets are preferably positively charged.

In a particularly preferred embodiment of the invention, the spraying apparatus is mounted on a trailer so it can be towed by a tractor or the like. The air compressor, the -4liquid pump and heat exchanger are preferably powered by a power take off shaft of the tractor through a gear box. Alternatively or additionally, the air compressor, liquid pump and heat exchanger may be powered by an engine mounted on the trailer.

Preferably, the apparatus includes at least two electrostatic nozzles, a right side electrostatic nozzle and a left side electrostatic nozzle, so that spraying to the left and right sides of the trailer can be achieved. First control means is preferably provided to control the flow of liquid to the electrostatic nozzles. Second control means is preferably provided to enable independent control of the right and left electrostatic nozzles.

Brief Description of the Drawings Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a schematic layout of a spraying apparatus in accordance with an embodiment of the invention (excluding details of the air path layout).

Figure 2 is a schematic layout of the air path of the spraying apparatus shown in Figure 1.

Detailed Description of a Preferred Embodiment Figure 1 illustrates schematically the layout of a spraying apparatus in accordance with an embodiment of the invention. The spraying apparatus includes a tank 10 for a liquid, a liquid pump 12, an air compressor 14 and a pair of electrostatic nozzles 16a, 16b.

Figure 1 illustrates the flow path of the liquid chemical through the spraying apparatus and into the electrostatic nozzles 16a, 16b. Figure 2 illustrates the flow path of air from the compressor 14 through to the electrostatic nozzles 16a, 16b.

As shown in Figure 1, the liquid tank 10 is divided into two compartments. The main and larger compartment 10a holds the liquid which is to be sprayed onto the crop. The liquid may be fertilizer or a pest control agent. The secondary and smaller compartment contains water for rinsing the electrostatic nozzles 16a, 16b. The flow path of liquid from the tank O10a to the electrostatic nozzles 16a, 16b will now be described.

The flow of liquid out of the tank 10a is controlled by a gate valve 18. Once through the gate valve the liquid passes through a filter 20 and then through the pump 12. The liquid pumped from the pump 12 passes through a further filter 22 before it enters a bypass arrangement 24. The function of the by-pass arrangement is to ensure that the pressure of the liquid does not exceed a predetermined pressure. For example, the bypass arrangement 24 is arranged to ensure that the pressure in the liquid path does not exceed 15 to 20 psi. Fluid may either be by-passed through by-pass line 26 and back into the tank O10a, or through the control valve 28. A pressure gauge 30 is included in the flow path to enable monitoring of the pressure in the liquid path by an operator. The liquid then flows through to a solenoid valve 32 which controls the flow of liquid into the electrostatic valve 16a, 16b. Thus it will be appreciated that by operating the valve 32 the flow of liquid to the electrostatic nozzles 16a, 16b can be turned on and off.

When the solenoid valve 32 allows liquid to flow into the electrostatic nozzles 16a, 16b it must first pass through a valve arrangement.

The operation of the by-pass line 26 also causes agitation of the contents of the tank This is important as it ensures that the contents of the tank 10a remain well mixed.

The valve arrangement 34 enables the operator of the spraying system to control whether both of the electrostatic nozzles 16a, 16b are to be in operation or whether only one of the electrostatic nozzles 16a, 16b is to be in operation. The liquid enters the electrostatic nozzles 16a, 16b at respective inlet points 36a, 36b where it is mixed with the air in such a manner that charged droplets of liquid are formed and then dispersed out of the electrostatic nozzles 16a, 16b. The electrostatic nozzles 16a, 16b operate in accordance with traditional technology.

-6- The air enters the electrostatic nozzles 16a, 16b via air inlet ports 40a, 40b. The flow of air from the air compressor 14 to the air inlet ports 40a, 40b will now be described. The air for the system is drawn from atmosphere and is cleaned in an air cleaner 38 before passing into the air compressor 14. The air from the air compressor 14 passes into a heat exchanger 42 which is arranged to take the air to the ideal air temperature for mixing with the liquid. Typically, the air is cooled to a lower temperature which makes the liquid more stable and thus better spraying of liquid can be achieved. The cooled air leaves the heat exchanger 42 and enters a by-pass arrangement 44. The by-pass arrangement 44 ensures that the pressure in the air path is maintained at a predetermined level. Ideally, the pressure in the air path does not exceed 15 to 20 psi. By-passed air passes through valve 46 and then returns to the air compressor 14. Alternatively, the air passes along the path 47 before some is diverted to airline 48 which feeds the valve arrangement 34. The remaining air flows into the air inlets 40a, 40b of the electrostatic nozzles 16a, 16b. The air and liquid are then mixed and a charge applied to the formed droplets before they exit the electrostatic nozzles 16a, 16b. The droplets form vapour which can be sprayed onto the plant. The droplets are preferably sized in the range of 60 im.

It will be appreciated that the charged droplets which are typically positively charged, are electrically attracted to the plant and therefore a uniform application of liquid is achieved. As the individual charged droplets are repelled from each other they tend to disperse more evenly over the target plant which is earthed. Earthing is achieved by an earthing chain or the like which extends to ground from the spraying apparatus.

It will also be appreciated by those skilled in the art that as the droplets used in the inventive spraying system are not dispersed at a high speed the canopy of the plant does not tend to collapse. Accordingly, all of the leaves of the plant, both top and bottom sides, achieve a coverage of liquid. Thus, more accurate and effective spraying of liquid is achieved and thus wastage of liquid is reduced. There is limited or no over spray as the charged droplets of the spray are attracted to the plant.

-7- In accordance with a preferred embodiment of the invention, the spraying apparatus is mounted on a small purpose built trailer which can readily be towed behind a tractor or the like. The pump 12, air compressor 14 and heat exchanger 42 can be powered by the power take off shaft 100 of the tractor through a gearbox arrangement 102.

Alternatively, or in addition, an engine may be mounted on the trailer to provide power to the pump 12, compressor 14 and heat exchanger 42.

The trailer is preferably mounted on two wheels and has a relatively low centre of gravity to ensure stability of the trailer.

The tank 10 is preferably a poly-chemical storage tank which is suitable for holding various chemicals which are used to spray plants.

The pump 12 is preferably a low pressure pump. The use of lower pressure liquid through the system will increase the life of the spraying system.

When a different liquid is to be sprayed by the spraying apparatus or spraying is complete the electrostatic nozzles 16a, 16b can be cleaned by operation of a water rinse.

Water rinse is achieved by allowing water to flow from the tank 10b, through a filter 120 whereafter the water is pumped by pump 122 into the valve arrangement 34. The water then flows through the inlets 36a, 36b to clean the electrostatic nozzles 16a, 16b.

The embodiments have been described by way of example only and modifications within the spirit and scope of the invention are envisaged.

Claims

1. A spraying apparatus for spraying an object, said apparatus including a tank for a liquid, a liquid pump, an air compressor and at least one electrostatic nozzle, said apparatus being arranged to emit charged droplets of the liquid which are attracted to the object to be sprayed.

2. A spraying apparatus according to claim 1 wherein the charged droplets are arranged to form a vapour which is sprayed onto the object.

3. A spraying apparatus according to claim 2 wherein the droplets of the vapour are each sized in the range of 50 60 tm.

4. A spraying apparatus according to any one of the preceding claims wherein the liquid tank includes at least two compartments, one of the compartments of the liquid tank being arranged to receive a first liquid to be sprayed on the object, and the other compartment being arranged to receive a rinsing fluid for rinsing said at least one electrostatic nozzle.

5. A spraying apparatus according to any one of the preceding claims further including a by-pass arrangement arranged to ensure that the liquid flowing to the electrostatic nozzle does not exceed a predetermined pressure.

6. A spraying apparatus according to claim 5 wherein the predetermined pressure of the liquid is between 15 and 20 psi.

7. A spraying apparatus according to claim 5 or claim 6 wherein the by-pass arrangement is further arranged to enable fluid to be directed back into the tank so as to cause agitation of the tank's contents.

8. A spraying apparatus according to any one of the preceding claims further including an air cleaner arranged to clean the air before it enters the air compressor. -9-

9. A spraying apparatus according to any one of the preceding claims wherein the air compressor is a rotary or a piston type compressor.

10. A spraying apparatus according to any one of the preceding claims further including a heat exchanger and a manifold and wherein the air compressor is arranged to pump compressed air through the heat exchanger prior to entry into the manifold.

11. A spraying apparatus according to claim 10 wherein the heat exchanger is arranged to control the temperature of the air so that it is at a preferred temperature for mixing with the liquid to be sprayed and the manifold is arranged to direct the air into the electrostatic nozzle.

12. A spraying apparatus according to any one of the preceding claims wherein the electrostatic nozzle is arranged to combine the air and liquid in such a way that positively charged droplets of liquid are formed and subsequently disbursed out the nozzle.

13. A spraying apparatus according to any one of the preceding claims wherein it is mounted on a trailer so it can be towed by a tractor or the like.

14. A spraying apparatus according to claim 13 when dependent from claim wherein the air compressor, pump and heat exchanger are powered by a power take off shaft of the tractor or the like.

A spraying apparatus according to claim 13 when dependent from claim wherein the air compressor, liquid pump and heat exchanger are powered by an engine mounted on the trailer.

16. A spraying apparatus according to any one of the preceding claims including at a right side electrostatic nozzle and a left side electrostatic nozzle, said nozzles being arranged so that spraying to the left and right sides of the trailer can be achieved.

17. A spraying apparatus according to any one of the preceding claims further including first control means to control the flow of liquid to the at least one electrostatic nozzle.

18. A spraying apparatus according to claim 16 further including second control means to enable independent control of the flow of liquid to the right and left side electrostatic nozzles.

19. A spraying apparatus according to any one of the preceding claims wherein the apparatus is for use in spraying plants, trees and/or vines.

A method of spraying plants, trees and/or vines, said method including the steps of: a) earthing the plants, trees and/or vines to be sprayed; and b) spraying the plants, trees and/or vines with a liquid using a spraying apparatus in accordance with any one of claims 1 to 19.

21. A spraying apparatus substantially as hereinbefore described with reference to the accompanying drawings.

22. A spraying method substantially as hereinbefore described with reference to the accompanying drawings. DATED: 19 September 2003 PHILLIPS ORMONDE FITZPATRICK Attorneys for: GREGORY GORDON MARSHALL and PENELOPE GLARE MARSHALL