WO1999008801A1

WO1999008801A1 - Fiber optic coupling for control of electrostatic field sprayers

Info

Publication number: WO1999008801A1
Application number: PCT/US1998/017036
Authority: WO
Inventors: Dennis L. Trusty
Original assignee: AGCO Corp
Current assignee: AGCO Corp
Priority date: 1997-08-18
Filing date: 1998-08-17
Publication date: 1999-02-25
Anticipated expiration: 2000-02-18

Abstract

A large field sprayer (10) uses electrostatically charged liquid spray in an agricultural field operation, where a high-voltage section (34) is to be kept isolated from the lower voltage section (17) that is essentially at ground potential. The high-voltage components include electrically-operated valves (50A, 50B, 50C), as well as other components (62, 63). A hydraulic motor (42) is used for driving a liquid pressurizing pump (44) on the high-voltage side (34) of the sprayer (10). A battery (54) for operating electric controls (58), valves (50A, 50B, 50C), other components (62, 63) is mounted on the high-voltage side (34) of the system, and an alternator (57) is coupled to the hydraulic motor (42) and is used for charging the battery (54). Power for operating the valves (50A, 50B, 50C) does not have to be carried on electrically conductive lines between the high and low-voltages sides (17, 34). The control signals for operating high voltage components are transmitted along fiber optic cables (53, 55).

Description

FIBER OPTIC COUPLING FOR CONTROL OF

ELECTROSTATIC FIELD SPRAYERS

BACKGROUND OF THE INVENTION The present invention relates to a system for reducing the paths for current leakage in an electrostatic spraying system for agricultural sprayers between the high-voltage components and the low-voltage, or grounded, components.

High-voltage spray guns for electrostatic paint spraying systems that have a self-contained high voltage supply right at the spray gun are known. For example, in an electrostatic paint spraying system such as that shown in U.S. Patent No. 5,218,305, electrical signals generated at a spray applicator and are fed back to a remote source by fiber optic cables utilizing light signals. However, a large agricultural electrostatic field sprayer travels over the earth, which is at a very low potential, raising more complex problems than in a paint-spraying system. It is desirable to have a high voltage power supply for controlled components, such as turn-on and turn-off valves for a field sprayer, carried on the high-voltage side without having electrical wires extending between the high and low-voltage sides.

SUMMARY OF THE INVENTION The present invention relates to a system for providing a battery on a high-voltage side of an electrostatic paint sprayer for controlling electrical components without having electrical wires connected between the high and low-voltage components. Light signals correlated to the control signals are carried by fiber optic cables. In the present invention, the power supply (battery) for energizing controls on the high- voltage side, such as flow control valves and the like, is carried on the high-voltage side, and a charging system driven from the motor used to drive the pressurizing spray pump recharges the battery.

The control signals are carried through fiber optic cables, which can well be insulated to reduce current leakage. The ability to recharge the battery on the high-voltage side permits operating components located on the high-voltage side without having a direct electrical connection from a battery on the low-voltage side to the high-voltage side. It also ensures that the battery that charges the components will remain fully charged for reliable and safe operation.

BRIEF DESCRIPTION OF THE DRAWINGS'

Reference is made to the drawings, wherein: Figure 1 is a schematic view of a typical agricultural field sprayer used with the present invention;

Figure 2 is a schematic view of a typical arrangement of a high-voltage platform used on a field sprayer;

Figure 3 is a schematic representation of a control system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figures 1 and 2, a self-propelled agricultural field sprayer is indicated generally at 10 and is mounted on a prime mover 11 that has suitable support wheels 12 for travel over the ground. The prime mover and the components directly mounted thereon compose a low-voltage side 17 of the electrostatic field sprayer. A frame assembly 14 is provided at the rear of the self-propelled vehicle to support a pair of spray booms that extend laterally from a center supply in opposite directions. One such boom, shown at 16, has a lower boom support 16 suspended on insulating rods 16B to support a laterally-extending spray pipe 13 that has nozzle 13A for discharging an electrostatically charged liquid. Additional insulating supports 15 can be used to cut down current leakage back to ground potential. A frame 20 has arms 22 that support portions of a high-voltage side or section 34, including a spray generator assembly 26, which is at a high voltage potential, through insulator rods 30. The sprayer system can include a center boom section 35 that is supported on insulating blocks 29 and 33 to the rear of high-voltage section 34. The high-voltage section ^'34 can be supported as shown and includes a tank 48 which carries liquid to be charged. A liquid supply system 47 provides the liquid spray material to the tank 48. At the lower end of tank 48, there is support 41 holding a pump 44 that is driven by a hydraulic motor 42 from a hydraulic pressure source 37 on the prime mover 11, which is on the low-voltage side 17. The liquid supply system for the spray material includes a suitable spray head 46, as is explained in U.S. Patent No. 5,363,799. A high-voltage power supply 45 is used for providing a potential to the pump 44 so that charged liquid is provided through a line 49 to a valve block 50 that has lines 50A, 50B, and 50C leading to individual sections of the spray pipes, for example, the spray pipes 35 and 13.

The valves in block 50 are solenoid valves powered from a battery 54 that is mounted on the support 41 and provides power on the high-voltage side 34 to the solenoids in the valve block 50. Battery 54 also provides electrical power to excite a float valve control 59 that is used for determining the level of liquid shown at 59A in supply tank 48. The battery 54 is recharged with an alternator 57, which is driven by the hydraulic motor 42. The motor 42, valves 50, alternator 56, and battery 54 are on the high-voltage side 34 of the field sprayer.

Referring to Figure 3, the control signals from the low-voltage side 17 are provided in a control module 56 that is shown in Figure 1 in the operator's compartment of the prime mover 11, and these signals are carried by a fiber optic cable 53 which connects to a control module 58, shown schematically in Figure 2 and also in Figure 3. A second fiber optic cable 55 is shown schematically and is used for transmitting light signals from control module 58 to control module 56. A simple fiber optic cable will carry all of the signals in actual use. The control modules 56 and 58 transmit and receive light signals to and from the fiber optic cables and convert the light signals from and into electrical signals on the respective high and low- voltage sides . Individual solenoid operated control valves 50A, 50B, and 50C form left, center, and right sprayer boom shut-off valves and are operated with power from battery 54. Control signals are also provided to a pressure adjustment valve that is electrically operated, and a flow meter signal is provided from a flow meter 63. The low-voltage side is represented at 17 in Figure 3, and the high-voltage side is represented at 34.

The fiber optic cables 53 and 55 receive and transmit control signals between the control modules 56 and 58 while the power for operating solenoid valves 50A, 50B, and 50C, as well as for energizing pressure adjustment valve 62 and the flow meter valve 63, are all powered by the battery 54 on the high-voltage side 34. There is no need for running electrical lines between the high- and low-voltage sides for these functions . The flow valve control 55 is energized by the battery 54 through the control module 58. Again, the control modules 56 and 58 can be standard modules that convert fiber optic signals to electrical signals and vise versa as desired. On the low-voltage side, the control module 56 includes a series of push-button or lever controls, such as those for operating the left- hand spray valves indicated at 70, the center spray valves indicated at 72, or the right-hand spray valves indicated at 74. A flow and pressure adjustment control 76 is also controlled by the operator and provides signals to the control module 56, carried by the fiber optic cable 53 to the control module 58 and then to the various components that are used. The alternator 57 is driven directly from the motor using a direct drive shaft or similar coupling, and will provide a sufficient output to maintain the battery 54 fully charged in a normal service sequence, without needing to stop the unit and have it charged from a separate source. The alternator output is controlled by a conventional voltage regulator. Any type of motor that is used for driving the pump 44 can be used for driving an alternator so that the battery can be mounted on the high-voltage side 34 without any electrical connecting wires or the like between the high and low-voltage sides for the electrical component.

The battery is selected to provide adequate power for operating the various valves, providing excitation for the flowmeter, and also providing excitation for the level control in the supply tank 48, which will be fed back through the control modules 58 and 56 to a supply valve 60, which will then provide flow from a source of liquid into the supply tank. This is normally done through a sprinkler head 61 shown in Figure 2.

The self-contained power unit on the high- voltage side, thus, is operated by fiber optic cable signals which are relatively easily insulated and provides for excellent isolation between the high and low-voltage sides.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. An agricultural sprayer having a prime mover for moving along the ground and supporting a spraying system comprising a plurality of spray nozzles attached to spray pipes extending laterally from the prime mover, the prime mover also supporting an electrostatic charging and spraying assembly comprising a pump and a motor for electrostatically charging liquid to be sprayed through the nozzles, the nozzles, the pump, and the motor being at a high voltage potential to form a high voltage side, and supported on a platform insulated from the prime mover and control input devices on the prime mover forming a low voltage side for controlling electrically operated components on the high voltage side, the improvement comprising a battery mounted on the high-voltage side for providing power for the electrical components on the high-voltage side, an alternator driven by the motor for providing a charging current to the battery on the high voltage side, and a fiber optic cable coupled between control modules on the high and low-voltage sides for carrying signals for controlling the electrical components on the high voltage side from control inputs on the low voltage side.

2. The apparatus of claim 1, wherein said electrical components include a plurality of solenoid valves on the high voltage side, and valve control inputs on the low voltage side connected by the fiber optic signals.

3. The apparatus of claim 1, wherein the electrical components include a float valve on the high- voltage for establishing a level of liquid in a tank and providing an electrical signal relative thereto, said float valve being excited by said battery, and the signals from said float valve being carried by fiber optic cable to the low-voltage side.

4. The apparatus of claim 1, including a control module on the low-voltage side for converting electrical signals to and from light signals carried by the fiber optic cable, and a controller on the high voltage side for converting electrical signals to and from light signals carried by the fiber optic cables between the high and low voltage sides .

5. In an agricultural field sprayer having a low- voltage side comprising a prime mover that moves over the ground and forms a power source, and a high-voltage side comprising a laterally extending sprayer boom for spraying liquid materials on the ground and including a charging system for providing an electrostatic charge to the liquid as it is pumped from a pump on the high- voltage side, wherein control signals are passed from a control module on the low-voltage side to a control module on the high-voltage side, the improvement comprising passing said signals as light signals along a fiber optic cable between the high and low-voltage sides of the agricultural sprayer.

6. The apparatus of claim 5 wherein said high voltage side has solenoid operated valves forming first components, and the control module on the low-voltage side providing signals to control said solenoid operated valves, along said fiber optic cable.

7. The apparatus of claim 6 including a battery mounted on said high-voltage side for providing power to said solenoid operated valves, a motor for driving the pump that pumps liquid to the spray booms on the high- voltage side, and an alternator driven by said motor for providing charging currents to said battery during operation of said motor and pump.