Electrically actuated variable pressure control system

Patent metadata

Field	Value
Publication number	US-2018043384-A1
Application number	US-201715790887-A
Country	US
Kind code	A1
Filing date	Oct 23, 2017
Priority date	Jun 7, 2005
Publication date	Feb 15, 2018
Grant date	—

Abstract

An electrically-actuated variable pressure control system for use with flow-controlled liquid application systems. Direct acting solenoid valves are pulsed at varying frequencies and duty cycles 0000 change the resistance to flow encountered by the flow-controlled liquid application system. This pulsing solenoid valve technique preserves a high degree of accuracy and uniformity through a wide range of pressure control. This wide range of pressure control indirectly allows the flow-controlled liquid application system to operate over a wider range of flow control, yielding indirect benefits to performance and productivity. When the solenoid valves are attached to pressure-atomization spray nozzles, control over spray pattern and droplet size is further achieved.

First claim

1 - 29 . (canceled)

30 . An agricultural spraying system comprising:
a valve including a nozzle and an actuator assembly, the nozzle having an orifice defined therethrough, the actuator assembly configured to be continuously pulsed according to a duty cycle to control emission of an agrochemical from the orifice; a pipe connected to the valve and configured to deliver the agrochemical to the valve; a pressure sensor connected to the pipe for sensing a pressure in the pipe; and a pressure controller in communication with the pressure sensor, the pressure controller configured to:
compare the sensed pressure to a pressure set point; and
change a flow resistance through the orifice based on the comparison by adjusting the duty cycle of the actuator assembly to maintain the pressure in the pipe at the pressure set point.

31 . The agricultural spraying system of claim 30 , wherein the agricultural spraying system further comprises a control panel configured to receive a user input, wherein the pressure controller is further configured to determine the pressure set point based on the user input.

32 . The agricultural spraying system of claim 31 , wherein the user input is the pressure set point.

33 . The agricultural spraying system of claim 30 , wherein the pressure set point is a single pressure value.

34 . The agricultural spraying system of claim 30 , wherein the actuator assembly is continuously pulsed at a frequency of 10 Hz.

35 . The agricultural spraying system of claim 30 , wherein the nozzle is a pressure-atomization spray nozzle configured to produce a desired droplet size spectra and an agrochemical spray pattern.

36 . The agricultural spraying system of claim 30 , wherein the actuator assembly includes a reciprocating solenoid actuator configured to move relative to the orifice when a voltage is applied to the reciprocating solenoid actuator.

37 . The agricultural spraying system of claim 30 , wherein the actuator assembly includes a coil, a guide, and a plunger, wherein the coil is disposed about the guide, and wherein the plunger is interposed between the guide and the orifice and moves relative to the orifice when a voltage is applied to the coil.

38 . The agricultural spraying system of claim 30 further comprising a plurality of valves, each valve of the plurality of valves including a nozzle and an actuator assembly, wherein the pressure controller adjusts the duty cycle of the actuator assembly of each valve independently of the other valves of the plurality of valves.

39 . The agricultural spraying system of claim 30 , wherein the pressure controller changes the flow resistance by adjusting the duty cycle of the actuator assembly to one of a plurality of duty cycles, the plurality of duty cycles including a maximum duty cycle, a minimum cycle, and at least one duty cycle between the maximum duty cycle and the minimum duty cycle.

40 . The agricultural spraying system of claim 30 , wherein the minimum duty cycle is 30% and the maximum duty cycle is 90%.

41 . The agricultural spraying system of claim 30 , wherein the actuator assembly is movable between an open position, in which the agrochemical is permitted to flow through the orifice, and a closed position, in which the actuator assembly seals the orifice.

42 . The agricultural spraying system of claim 41 , further comprising an actuating signal generator for controlling actuation of the actuator assembly between the open position and the closed position.

43 . The agricultural spraying system of claim 42 , wherein the actuating signal generator is a square wave generator configured to actuate the actuator assembly from the closed position to the open position by applying a voltage to the actuator assembly.

44 . The agricultural spraying system of claim 43 , wherein the square wave generator is configured to modulate a square wave frequency and the duty cycle to change the flow resistance for the emission of the agrochemical from the orifice.

45 . The agricultural spraying system of claim 44 , wherein the pressure controller includes the square wave generator.

46 . The agricultural spraying system of claim 30 , wherein the pressure controller changes the flow resistance through the orifice by increasing the duty cycle at which the actuator assembly is pulsed to decrease the flow resistance when the sensed pressure exceeds the pressure set point.

47 . The agricultural spraying system of claim 30 , wherein the pressure controller changes the flow resistance through the orifice by decreasing the duty cycle at which the actuator assembly is pulsed to increase the flow resistance when the sensed pressure is less than the pressure set point.

48 . The agricultural spraying system of claim 30 further comprising an agrochemical tank for holding the agrochemical, the agrochemical tank connected to the pipe.

49 . The agricultural spraying system of claim 30 further comprising a pump for pumping the agrochemical through the pipe.

50 . The agricultural spraying system of claim 49 , wherein the pump is one of a positive displacement pump and a centrifugal pump.

51 . The agricultural spraying system of claim 49 , wherein the pump is a positive displacement pump, the agricultural spraying system further comprising a wheel and a piston, wherein the piston is connected to the wheel and to the positive displacement pump, and wherein the piston is configured to reciprocate the positive displacement pump as the wheel turns.

52 . A method for regulating pressure for application of an agrochemical from an agricultural spraying system, the method comprising:
directing the agrochemical through a pipe of the agricultural spraying system to an actuating valve including a nozzle and an actuator assembly, the nozzle having an orifice defined therethrough; continuously pulsing the actuator assembly according to a duty cycle to control emission of the agrochemical from the orifice; sensing a pressure in the pipe using a pressure sensor connected to the pipe; comparing, using a pressure controller, the sensed pressure to a pressure set point; and changing a flow resistance through the orifice, using the pressure controller, based on the comparison by adjusting the duty cycle of the actuator assembly to maintain the pressure in the pipe at the pressure set point.

53 . The method of claim 52 further comprising:
receiving a user input at a control panel; and
determining, using the pressure controller, the pressure set point based on the user input.

54 . The method of claim 53 , wherein the user input is the pressure set point.

55 . The method of claim 52 , wherein changing a flow resistance through the orifice includes transmitting control signals from the pressure controller to the actuator assembly, the control signals being associated with the duty cycle.

56 . The method of claim 55 , wherein the control signals are generated by a square wave generator associated with the pressure controller.

57 . The method of claim 52 , wherein changing a flow resistance through the orifice includes increasing the duty cycle at which the actuator assembly is pulsed in order to decrease the flow resistance when the sensed pressure exceeds the pressure set point.

58 . The method of claim 52 , wherein changing a flow resistance through the orifice i

Assignees

• Capstan Ag Systems Inc

Inventors

• Grimm Jeffrey John
• Henderson Graeme W

Classifications

• A01G25/16

  Control of watering · CPC title

• B05B9/0413

  with reciprocating pumps, e.g. membrane pump, piston pump, bellow pump (B05B9/0409 takes precedence) · CPC title

• B05B9/0423

  for supplying liquid or other fluent material to several spraying apparatus · CPC title

• F16K31/0655

  Lift valves · CPC title

• B05B12/085 Primary

  responsive to flow or pressure of liquid or other fluent material to be discharged (B05B1/3006, B05B1/323 take precedence; spray pistols designed to control volume of flow with the controlling means being fluid actuated B05B7/1254) · CPC title