Method and apparatus for pumping a fluid additive into an irrigation system for field application

An irrigation system 10 for distributing a primary fluid or water supply over a ground surface 2 of a field 1, the irrigation system 10 including:

• an irrigation apparatus 12 movable over the ground surface 2 to distribute a primary fluid over the ground surface 2 within a field sector 3 of a field 1, the irrigation apparatus 10 comprising:
• a center structure configured to support a first-end of a first span and provide an apparatus for of centering the rotation of the distal-ends of a plurality of interconnected spans extending outward from said center structure;
• at least two spans 14, 16 and preferably three or more spans 14, 16, 17 generally having a first-end of span closest to the center structure and a distal-end of span extending along a longitudinal axis 18 of the irrigation apparatus 12;
• at least one support tower 20, 22, 23 for each span 14, 16,17 configured to support the corresponding spans 14, 16, 17 at a location above the ground surface 2;
• a fluid application assembly 30 with a fluid supply conduit 34 configured to apply a primary fluid to the ground surface 2 of a sector 3 of the field 1;
• a fluid additive pumping apparatus 50 configured to pump a fluid additive 8 into the primary fluid or water supply distributed by the fluid application assembly 30 of the irrigation apparatus 12 as the irrigation apparatus 12 moves over a sector 3 of the field 1, the fluid additive pumping apparatus 50 comprising:
• a fluid additive pump assembly 58 in fluid communication with a fluid additive reservoir 54 and a fluid additive injector element 56 by means of a fluid additive path 52, said path originating at said reservoir 54 and terminating at said injector element 56. Said fluid additive pump assembly 58 may be configured to pump a predetermined volume of fluid additive 8 into the fluid application assembly 30 in a predetermined period of time for distribution of fluid additive 8 to a sector 3 of the field 1. Said predetermined period of time to pump the predetermined volume of fluid additive 8 may be used to determine a rate of pumping, said rate of pumping for said predetermined period of time also corresponding to a period of time for spans 14, 16, 17 to transition over a sector 3 of the field 1 at an intended speed of movement over the ground surface 2, following a corresponding wheel track 29 for the distal-end of the outermost span 17, from a start position 42 to a stop position 43 of a sector 3;
• a pump apparatus controller 90 with a memory 91 and a processor 92, wherein said pump apparatus controller 90 has stored in memory 91 a start position 42, a stop position 43, a predetermined start time and predetermined stop time for application of additive 8 to a sector 3 of a field 1;
• a position sensor assembly 46 in communication with the pump apparatus controller 90, said position sensor assembly 46 configured to periodically sense at a current time a current position within a corresponding wheel track 29 of the distal-end of the outermost span 17 of the irrigation apparatus 12 within a sector 3 of a field 1;
• and
• a fluid additive flow sensor 66 in communication with the pump apparatus controller 90, said flow sensor 66 configured to monitor the rate of flow of the fluid additive 8 being pumped through the fluid additive path 52 by fluid additive pump assembly 58;
• and
• wherein said pump apparatus controller 90 may be in communication with said position sensor assembly 46, said fluid additive pump assembly 58 and said fluid additive flow sensor 66 and may receive a current position signal and a current time from said position sensor assembly 46 and may store said current position and current time in said memory 91. The pump apparatus controller 90, using memory 91 and processor 92, may calculate an actual speed of movement of the distal-end of the outermost span 17 as said span transitions through a sector 3 of the field 1 following a corresponding wheel track 29. Based on the calculated actual speed of movement, as compared to an intended speed of movement, the processor 92 further calculates an adjusted fluid additive 8 pumping rate. Said adjusted fluid additive 8 pumping rate may be proportionally decreased when the actual speed of movement of the distal-end of the outermost span 17 may be slower than the intended speed of movement. Said adjusted fluid additive 8 pumping rate may be proportionally increased when the actual speed of movement of the distal-end of the outermost span 17 may be faster than the intended speed of movement. The adjustments to the rate of pumping by the fluid additive pump assembly 58 may be configured to be performed periodically;
• and further wherein said pump apparatus controller 90 calculates the adjusted pumping rate based on an actual speed of movement of the distal-end of the outermost span 17 calculated from a current position, a current time and a user defined stop position 43 and calculates a remaining time period for the outermost span 17 to reach said stop position 43 and wherein said pump apparatus controller 90 monitors the output of the fluid additive flow sensor 66 and controls the fluid additive pump assembly 58 to pump fluid additive 8 at an adjusted rate so as to distribute the remaining supply of fluid additive 8 being pumped to a sector 3 of a field 1, as irritation apparatus 12 continues moving to reach a user-defined stop position 43 in a remaining time period, based on said calculated actual speed of movement for said distal-end of the outermost span 17.