AU3503801A - Control system for controlled droplet application spray - Google Patents

Description

10657

ORIGINAL

Complete Specification Applicant: Inventor: Title: Address for Service: Allan Ranford Allan Ranford Control system for controlled droplet application spray LESICAR PERRIN, 168 South Terrace, Adelaide, South Australia 5000, Australia The following statement is a full description of this invention, including the best method of performing it known to me/us: Control system for controlled droplet application spray FIELD OF THE INVENTION The present invention relates to a controlled system for a controlled droplet application spray apparatus. Controlled droplet application (CDA) spray apparatus is used in agricultural typically to apply chemical products, for example liquid herbicides and insecticides, over wide areas of land.

BACKGROUND OF THE INVENTION CDA utilises pumping equipment to supply liquid herbicide or pesticide over a wide oooo area of land.

CDA apparatus typically utilises pumping equipment to supply the liquid to be sprayed to a pair of opposed spray heads distributed on either side of a vehicle on a boom. A °typical CDA apparatus is described in US patent no 5419493. The spray heads of the apparatus are adapted to atomise the liquid into a very fine droplet spray. Each CDA spray head includes a motor which spins a CDA disc. The size of the droplet produced 15 and the distance the spray droplets travel is regulated by the pump flow and the speed at which the motor spins the CDA disc. A particular advantage of this type of apparatus is the production of a very fine mist of the chemical to be applied within a shroud that is used to contain any drift of the chemical.

In order to produce the ultra low volume, ultra low pressure conditions best suited to operation of CDA apparatus the liquid flow rate in the system is regulated by an inline flow meter specially modified to pump and a bypass system. The control system incorporates a light which is used to reduce speed of the CDA motor and thereby regulate the droplet size and pattern. The speed of the motor is adjusted by adjusting the wattage of the bulb included in the light. As the light draws power from the motor so the speed of the motor decreases and hence the droplet size increases. However, this system has a tendency to fail as a result of the overheating of the motor.

It is also important to note that in current systems the flow to each CDA head is monitored through an inline flow meter, which for ease of operation can be located within the cabin of the vehicle on which the spray system is mounted, or in front of and near the operator of open cab spray vehicle, which can contaminate the operator.

When a particular spray head is not required, for example when operating at an edge of the area to be treated, the flow to the spray head is disconnected at the flow meter.

Thus, there is a significant risk of chemical contamination within the cabin, and a risk of contact between an operator and the chemical or inhalation of the chemical. This obviously poses health and safety problems for operators of such systems.

BRIEF SUMMARY OF THE INVENTION The present invention has been designed as an alternative to existing systems.

Therefore, according to a first aspect of the present invention there is provided a control system for a controlled droplet application spray system including a first speed controller adapted to reduce pump pressure and supply flow of liquid to a CDA spray head and a second speed controller associated with each spray head, the second speed controller further including flow meter indicator means wherein the indicator 15 means are located separate from the flow meter.

Preferably, the first speed controller has an associated bypass system that enables flow from a pump to bypass the speed controller to thereby allow maximum flow where required. Thus, although the control system of the present invention allows the operator to control the spray system, it is also possible to bypass the spray system to 20 allow full pressure spot spraying where required, or nozzle pressure spraying of different chemicals not suited to CDA spraying, through conventional spray nozzles.

More preferably still the control system includes an inline amp meter used to monitor a CDA head to indicate flow rate and/or malfunctions of the head. During correct operation the motor speed and pump flow will be reflected in an amp meter reading within a predetermined range. Variations in flow rate, either of too high a flow rate or too low a flow rate will be reflected in an amp meter, and would draw attention of the operator. The display on the meter is preferably a visually distinguishable reading.

Examples of events that could alter the reading from a correct flow rate to an incorrect flow rate include a lack of flow from the pump, or alternative a blocked nozzle allowing no flow therethrough. Similarly, if the CDA disc is disconnected from the CDA head an incorrect flow rate will be shown. Similarly, where the flow rate is too high, the motor is failing or the disc is jammed this will be reflected in an altered reading providing superior monitoring of the spray system.

It can be observed that the CDA control system of the present invention allows the flow indicator means in the form or the speed controller to be located within the cabin of a vehicle carrying the CDA system. By contrast systems currently in use include a separate inline flow meter for each individual head in which the liquid to be metered is pumped through the control system and therefore through the vehicle cabin. The pump speed controller also allows the flow rate to be adjusted for best operation, from the cab.

The control system on the present invention further includes an inline solenoid associated with each CDA head to prevent flow to the CDA head when the CDA motor is disconnected. The solenoid has two main effects. Firstly, to prevent flow to the CDA remotely, avoiding the need for hand disconnection of chemical lines, the system operated in current systems. In addition, an inline solenoid prevents syphoning of liquid 15 from the tank when the spray unit is left unattended.

Further, the solenoid has an associated built in regulator to prevent over voltage from the vehicle charging systems having an adverse effect on the solenoid for CDA speed controller. For example, a vehicle may charge between 13 ahd 14 volts, which is too high for a solenoid operating on a 12 volt system. Accordingly, the regulator is 20 provided to prevent damage to the solenoid occurring as a result of over voltage from the vehicle.

The system of the present invention is further provided with a flow meter attached to a supply tank to monitor actual consumption flowing into the control system. The flow meter attached to the tank can also serve as a means of double checking results from the inline speed controller and regulator of the system.

The tank further includes a bypass system to return any excess flow to the tank when one CDA head is not in use. This prevents a 12 litre per hour flow to two heads becoming a 24 litre per hour flow to a single head. The bypass system also acts to agitate the contents of the tank.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will now be described with reference to the accompanying figure which illustrates schematically a control system with a first aspect of the present invention.

Shown in the drawings is a control system 10 for use with a CDA spray apparatus. The system 10 as illustrated shows components that may be located on a spray boom, within a vehicle cabin and mounted on the vehicle itself.

The system 10 includes a storage tank 12 which would, typically, be mounted on the vehicle.

10 The storage tank 12 includes a larger water storage tank 12a and a smaller chemical storage tank 12b. The larger tank 12a serves as a reservoir of diluting water and the smaller tank 12b allows for containment of the chemicals to be distributed. Also associated with the storage tank 12 is a mixing vessel 13. Each of the water storage tank 12a and the chemical storage vessel 12b have a respective fluid supply line 40, 42 leading into the mixing vessel 13. The supply line 40 leading from the water storage tank leads into an upper side of the mixing vessel 13 and is controlled by non returnvalve 44. The supply line 42 leading from the chemical storage vessel 12b, as shown in the drawings leads into the upper edge of the vessel 13. Flow through the supply line S 42 is regulated by non-return valve 46 which has a controller 48 attached thereto. The regulation of chemical supply is important to ensure that the appropriate dilution is made, accordingly, it is sensible for the flow to be regulated through a fairly sensitive control. As a check on the flow of material through the line 42 an in line flow meter provides a second indication of flow.

The mixing vessel 13 has an outlet 52 that leads to a pump 18. A second outlet 54 from the vessel 13 leads to a non-return bypass valve 16. The by pass line 54 flows into an outlet line 54 from the pump 18. The bypass valve 16 ensures that any excess flow through the system is returned to the tank 12. Thus, if for example, flow to one CDA head is abruptly stopped the bypass valve 16 ensures that a flow of 12 I/hr to each of the two CDA heads does not suddenly become a flow to a single CDA head of 24 I/hr. The bypass valve 16 also serves to agitate the contents of the storage tank 12 which is generally desirable.

Closure of the bypass valve 16 enables the system to be primed initially for first use.

The pump 18 connects to the CDA heads 20. Attached to an outflow side of the pump 18 is a connector 22. The connector 22 allows connection of the outflow of the pump to either the CDA head array 20 or to a hand wand 24 for spot spraying or pressure nozzle spraying.

The flow from pump 18 through the CDA heads is monitored and regulated by speed controller 26. It can be seen that the speed controller 26 makes only an electrical connection with the pump 18 rather than being in line. Thus, the speed controller 26 allows the flow rate from the pump 18 to be regulated externally and from a remote 10 location. In addition the pump has an independent flow meter 19.

The speed controller 26 connects to a series of inline meters 28. Each meter 28 is associated with a respective spray head 20. Furthermore, each in line meter 28 and °oo° CDA head 20 has a respective solenoid 30 connected thereto. In alternative arrangements of the invention a single meter can be used to monitor flow to all of the 15 heads Each CDA head 20 includes a disc (not shown) inside a conical housing 32. The disc is spun via a motor generally indicated at 34. The speed of the motor 34 controls the speed of the CDA disc which, in turn, regulates the droplet size and extent of travel.

The speed controller 26, ensures that the flow to the CDA heads has a primary source of control. Further, adjustment of the speed controller 26 allows the flow to be switched between the CDA heads and the hand pump 24, thereby allowing spot spraying.

The inline meters 28 each indicate the flow rate for the respective head, conveniently via a visually readily discernible needle display.

The needle can display very low flow conditions, which might indicate malfunctions such as the CDA disc, becoming detached, a block flow nozzle or simply low flow that needs adjustment. Similarly, where the needle indicates high flow there may be other malfunctions such as a jammed CDA disc or a failing motor.

It is interesting to note that the speed controller of the present invention is that the controller 26 effectively reduces the flow rate to the CDA head thereby allowing the motor to run at approximately half its maximum speed. By contrast, prior art systems use a light in line as described. Flow is adjusted by increasing the power supply required by the light by increasing the bulb wattage. The CDA motor therefore is required to run at near maximum speed during its entire operation which has a deleterious effect on the life of the motor.

As will be appreciated, the speed controller 26 and Amp meters 28 are not part of the fluid flow of the CDA system. As such these devices can be located in the vehicle cabin with no requirement for any of the chemical to be dispersed to also be in the cabin.

The solenoid 30 ensures that flow to the CDA head 20 can be remotely interrupted when the hand wand 24 is needed. The solenoid also assists in preventing flow siphoning to the tank when the spray unit is unattended. The inline meters 28 regulate the solenoids 30 to ensure that over voltage, eg from the vehicle charging system cannot burn out the solenoid. For example, the vehicle can charge from 13 to 14 volts, 15 this is too high for the 12v solenoid. The speed controller 26 therefore acts to allow S. variability of the spray pattern, to ensure that the spray pattern from each head is not affected when flow to remaining heads is adjusted, and that the flow to one CDA head, 0. or to one side of the vehicle is unaffected when the remaining side is stopped.

33 represents conventional low volume spray nozzles. Controller 26 can control 20 optimum spray volume as well.

Claims (12)

1. A control system for a controlled droplet application spray system including a first speed controller adapted to reduce pump pressure and supply flow of liquid to a CDA spray head and a second speed controller associated with each spray head, the second speed controller further including flow meter indicator means wherein the indicator means are located separate from the flow meter.

2. A control system according to claim 1, wherein the first speed controller has an associated bypass system that enables flow from a pump to bypass the speed controller to thereby allow maximum flow where required.

3. A control system according to claim 2, wherein the bypass system is adapted for connection to a hand wand to facilitate full pressure spot spraying and nozzle pressure spraying of different chemicals not suited to CDA spraying, through conventional spray nozzles.

4. A control system according to claim 1, wherein the control system includes an 15 inline amp meter used to monitor a CDA head to indicate flow rate and/or malfunctions of the head.

5. A control system according to claim 4, in which the inline amp meter includes a having a visually distinguishable reading.

6. A control system according to claim 1, wherein the flow indicator means and/or the speed controller are adapted to be located within the cabin of a vehicle carrying the CDA system.

7. A control system according to claim 6, in which the pump speed controller also allows the flow rate to be adjusted for best operation, from within the cabin of a vehicle carrying the CDA system.

8. A control system according to claim 1, wherein the control system further includes an inline solenoid associated with each CDA head to prevent flow to the CDA head when the CDA motor is disconnected.

9. A control system according to claim 8, wherein each solenoid has an associated built in regulator to prevent over voltage from vehicle charging systems having an adverse effect on the solenoid for CDA speed controller.

A control system according to claim 1,in which the apparatus is further provided with a flow meter attached to a supply tank to monitor actual consumption flowing into the control system.

11. A control system according to claim 10, wherein the flow meter attached to the tank can also serve as a means of double checking results from the inline speed controller and regulator of the system. 10

12. A control system for a controlled droplet application spray system as defined in claim 1, substantially as hereinbefore described and as illustrated in the accompanying drawings. 15 Dated this 9th day of April 2001 Allan Ranford By his Patent Attorneys o-O 20 Lesicar Perrin "20