Fluid sprayer system using modulated control valve and a positive displacement pump

• US 6,883,726 B2
• Filed: 10/04/2002
• Issued: 04/26/2005
• Est. Priority Date: 01/16/2002
• Status: Active Grant

• Current Assignee: Toro Company (Toro)
• Original Assignee: Toro Company (Toro)
• Inventors: Story, John, Polk, Brannon, Hahn, Kent Stephen
• Primary Examiner(s): TRIEU, THAI BA
• Application Number:
  US10/264,671
• Publication Number:
  US 20030132310A1
• Time in Patent Office: 935 Days
• Field of Search: 239/159, 239/172, 239/1, 239/71, 239155-156, 239/163
• US Class Current: 239/159
• CPC Class Codes: B05B 9/0409 the pumps being driven by a hydraulic or a pneumatic fluid
• CPC Class Codes: B05B 9/06 the delivery being related to the movement of a vehicle, e.g. the pump being driven by a vehicle wheel

Abstract

A fluid sprayer system using a modulated hydraulic control valve and a positive displacement pump to control the amount of fluid sprayed by the system. The modulated hydraulic control valve may be controlled using pulse width modulation and may be provided with a substantially constant source of hydraulic fluid. The pulse width modulated hydraulic control valve provides the hydraulic fluid to a hydraulic motor as a controlled flow. The controlled flow serves to control the hydraulic motor that controls a positive displacement pump. The position displacement pump is used to control the amount of fluid sprayed by the system. The control system changes the signal to the control valve so as to mitigate pressure changes otherwise caused by said positive displacement pump.

Claims

1. A spray system, comprising:

a plurality of booms mounted on a base structure;

a plurality of nozzles disposed on said booms;

a control system;

a hydraulic control module comprising an electronically operated valve, wherein the valve is in electronic communication with the control system;

a hydraulic motor in communication with the hydraulic control module, wherein operation of the hydraulic motor is controlled by the hydraulic control module;

a positive displacement pump linked to said the hydraulic motor, wherein operation of the positive displacement pump is controlled by the hydraulic motor and wherein the positive displacement pump provides pressurized flow of the liquid solution to said booms;

a square wave signal being communicated from said control system to said electronically operated valve; and

said square wave signal being adjustable by an open loop routine of said control system, said routine being immediately executable upon a change in the state of flow through said nozzles in at least one of said booms, said square wave signal being adjustable so as to mitigate pressure changes in said spray system.

2. The spray system of claim 1, wherein the positive displacement pump is a diaphragm pump.

3. The spray system of claim 1, wherein said square wave signal is a pulse width modulated signal.

4. The spray system of claim 1, wherein said spray system is fixed on a vehicle.

5. The spray system of claim 1, wherein said change in state of flow through said nozzles is a change in the flow rate of said liquid solution flowing through said spray system.

6. The spray system of claim 1, wherein said change in state of flow through said nozzles is caused by an opening of a previously closed nozzle.

7. The spray system of claim 1, wherein said change in state of flow through said nozzles is caused by a closing of a previously open nozzle.

8. A system for mitigating pressure changes in a spray system comprising:

a control system having a plurality inputs and at least one square wave signal output;

a speed sensor connected to one of said inputs;

a flow meter connected to one of said inputs;

a plurality of flow nozzles associated with at least one of said inputs;

a positive displacement pump associated with said spray system and having an outlet in selective fluid communication with said flow nozzles; and

a control valve linked to said positive displacement pump, said control valve connected to said square wave output of said control system;

said control system having a routine wherein a speed of said positive displacement pump is changed by said control valve via an adjustment of a square wave signal delivered from said control system to said valve, said change being proportional to a sensed change in at least one of said inputs of said control system, and wherein said routine comprises an open loop subroutine which executes immediately upon the occurrence of said sensed change.

9. The system of claim 8, wherein said sensed change is a change detected by said flow meter.

10. The system of claim 8, wherein said square wave signal is a pulse width modulated signal.

11. The system of claim 8, wherein said sensed change is a change in state of at least one of said flow nozzles.

12. A method for mitigating pressure changes in a chemical sprayer system comprising:

monitoring a plurality of spray parameters in said sprayer system;

controlling a positive displacement pump using a valve controlled by a square wave signal; and

adjusting the square wave signal to said valve with an open loop subroutine immediately upon detection of a change in the state of at least one of said spray parameters, said adjustment being directly proportional to a target speed of said displacement pump, said target speed being selected based on said detected change in state.

13. The method of claim 12, wherein said detection of a change in state is the detection of a change in the state of a boom control valve of said sprayer system.

14. The method of claim 13, wherein adjusting of the square wave signal takes place prior to finalization of said change in state of said boom control valve of said sprayer system.

15. The method of claim 14, wherein said adjustment to said square wave is proportional to a ratio of nozzles continuing to accept flow after said change in state of said control valve to nozzles no longer accepting flow after said change in sate of said control valve.

16. A method for mitigating pressure changes in a chemical sprayer system comprising:

monitoring a plurality of spray parameters in said sprayer system;

controlling a positive displacement pump using a valve controlled by a square wave signal;

adjusting the square wave signal to said valve upon detection of a change in the state of at least one of said spray parameters, said adjustment being directly proportional to a target speed of said displacement pump, said target speed being selected based on said detected change in state,

wherein said detection of a change in state is the detection of a change in the state of a boom control valve of said sprayer system;

wherein adjusting of the square wave signal takes place prior to finalization of said change in state of said boom control valve of said sprayer system; and

wherein said adjustment to said square wave is proportional to a ratio of nozzles continuing to accept flow after said change in state of said control valve to nozzles no longer accepting flow after said change in sate of said control valve.