Variable Rate Application Equipment and Mechanisms Introduction Mapping
Variable Rate Application Equipment and Mechanisms
Introduction Mapping or on-board sensors n Requirement for rapid changes in rate n Requirement for accurate and precise rate acquisition n Requirement for accurate and precise distribution and deposition n
Principles of Chemical Application Perfect uniformity not possible n Physical laws dictate rate and distribution n Metering and distribution device designs control performance n
Liquid Metering ‘Controlling the rate of flow’
Orifice Flow
Ag. Chem Variable Rate Applicator
Case-Tyler-Capstan Air command System
How do we change rates and treat small areas? n Variable Rate Spray Nozzles Sensor Assy. n Sensed Area Valves must operate at high speeds Valves must enable stepping of rates – e. g. 1 x, 2 x, 4 x combinations for 1 x, 2 x, 3 x, 4 x, 5 x, 6 x, 7 x, and off rates
Patchen Cartridge Valve n n Designed as part of the Weedseeker sense/spotspray system Poppet-type cartridge valve
Patchen Schematic n n Discharge Coefficient: 0. 07 gpm/(psi^0. 5) Steady State Current Requirement: 0. 32 Amps
Why Minimum Treatment Distance? Variable Rate Spray Nozzles n n Sensor Assy. Sensed Area Need application resolution to match sensed resolution Treatment Distance i a function of a minimum treatment time and ground speed.
Tri-valve Set for Varying Rate n n Stepped rates 1 x, 2 x, 3 x, 4 x, 5 x, 6 x, 7 x and off Can treat 0. 6 by 0. 6 m area applying the target rate on 85% of that area
Stepped Application Using a 3 Valve Set
OSU/Green. Seeker Unit 1 N-Fertilizer Applicator
Green. Seeker RT 200 Green. Seeker RT 500
Green. Seeker RT 200 Green. Seeker RT 500
RT 200 and RT 500 Specifications RT 500 RT 200 n n n Estimated Price $15, 000 for 60 ft applicator Senses and treats boom width by 20 to 30 feet Utilizes existing variable rate sprayer controllers and valves Combination Sense and Treat, and Sense, Predict, and Treat strategies Reaction time limited by existing controller and valves n Estimated Price $60, 000 for 60 ft applicator No Longer Manufactured Senses and treats each 2 ft by 2 ft area Uses NTech high speed and high resolution controller and valves Sense and Treat strategy n Reaction time < 0. 1 s n n n
RT 200 and RT 500 Specifications n RT 200 Reaction time limited by existing controller and valves – Capstan Pulse Width Modulation 3 to 10 Hz, 0 to 8 x – Raven type flow control valve 1 to 5 s, 1 to 2. 5 x RT 500 Reaction time < 0. 1 s
30 ft by 60 ft Sensing and Treatment Scale and Strategy RT 200 Treated Area Sense, Predict, and Treat Strategy RT 500 High Resolution Sense and Treat Strategy 2 ft by 2 ft
Sensing and Treatment Scale
Sensing and Treatment Scale Green. Seeker RT 200 Equipped with Capstan PWM Sharpshooter
RT 200 and RT 500 Specifications RT 500 RT 200 n n 6 sensors on 60+ ft boom Can readily be mated with existing dry fertilizer and anhydrous ammonia applicators Fast installation with minimal modifications System intended for fertilizer and possibly products such as growth regulators and defoliants n n n 30 sensor on 60 ft boom Existing dry fertilizer applicators cannot be used with this system System custom installed on each manufacturer’s sprayer /boom Can detect and spray weeds in fallow/no-till as well as apply fertilizer System can be used for other crops and materials
Ag Chem Variable Rate Granular Materials Applicator
- Slides: 26