Boom Flow Characteristics With Direct Chemical Injection

Tompkins, F. D.; Howard, K. D.; Mote, C. R.; Freeland, R. S.

doi:10.13031/2013.31394

Cited by 24 publications

(9 citation statements)

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“…Anglund and Ayers (2003) evaluated a direct injection system and found the lag time for the active ingredient (chemical concentrate) was between 15 and 55 s based on the carrier flow rate. Tompkins et al (1990) conducted a study regarding the effects of injection location (immediately upstream and downstream of the pump and at each nozzle) on response time and chemical concentration variation of the nozzle discharge. Results indicated a decrease in the transient time required to produce a uniform chemical concentration at the nozzle as the injection point moved closer to the nozzle.…”

Section: Direct In-line Injection Systemsmentioning

confidence: 99%

Recalibration Methodology to Compensate for Changing Fluid Properties in an Individual Nozzle Direct Injection System

Luck¹,

Shearer

Luck

et al. 2016

Trans. ASABE

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Right click to open a feedback form in a new tab to let us know how this document benefits you.ABSTRACT. Limited advancement of direct injection pesticide application systems has been made in recent years, which has hindered further commercialization of this technology. One approach to solving the lag and mixing issues typically associated with injection-based systems is high-pressure individual nozzle injection. However, accurate monitoring of the chemical concentrate flow rate can pose a challenge due to the high pressure, low flow, and changing viscosities of the fluid. A methodology was developed for recalibrating high-pressure chemical concentrate injectors to compensate for fluid property variations and evaluate the performance of this technique for operating injectors in an open-loop configuration. Specific objectives were to (1) develop a method for continuous recalibration of the chemical concentrate injectors to ensure accurate metering of chemicals of varying viscosities and (2) evaluate the recalibration method for estimating individual injector flow rates from a system of multiple injectors to assess potential errors. Test results indicated that the recalibration method was able to compensate for changes in fluid kinematic viscosity (e.g., from temperature changes and/or product variation). Errors were less than 3.4% for the minimum injector duty cycle (DC i ) (at 10%) and dropped 0.2% for the maximum DC i (at 90%) for temperature changes of up to 20°C. While larger temperature changes may be expected, these test results showed that the proposed method could be successfully implemented to meet desired injection rates. Because multiple injectors would be used in commercial deployment of this technology, a method was developed to calculate the desired injector flow rate using initial injector calibration factors. Using this multi-injector recalibration method, errors ranged from 0.23% to 0.66% between predicted and actual flow rates for all three injectors.

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Section: Direct In-line Injection Systemsmentioning

confidence: 99%

Recalibration Methodology to Compensate for Changing Fluid Properties in an Individual Nozzle Direct Injection System

Luck¹,

Shearer

Luck

et al. 2016

Trans. ASABE

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“…The chemical application system model developed in this work uses DIS technology with the injection point located upstream from the sprayer pump as in Tompkins et al (1990), Antuniassi et al (2002), Sui and Thomasson et al (2003), and Gillis et al (2003). The application system is composed of the chemical injection and carrierchemical mix sub-systems ( fig.…”

Section: Chemical Injection Sprayer System Descriptionmentioning

confidence: 99%

Modeling and Model Validation of a Chemical Injection Sprayer System

2016

Appl. Eng. Agric

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Efficient control strategies can be used to avoid off-target application in the operation of variable rate application sprayers. The main processes involved in the operation of a variable rate application sprayer are the injection of chemical and its mixing with the carrier. Therefore, the objective of this research was to develop mathematical models for a chemical direct injection system (DIS) including the carrier-chemical mix to assist the design and prediction of the variable rate application errors. The modeling of the DIS involves different engineering fields and is based on the physical parameters of the hydraulic and electrical-mechanical components, fluid equations and experimental procedures.The developed models for the chemical DIS were validated via a normalized root mean square error (RMSE) index using a laboratory-scale sprayer test bench built to design sprayers and analyze their performance. These models captured the realistic operation of the chemical injection system including the effect of the transport delay which is dependent on the carrier-chemical mix flow rate. Experimental results of the DIS flow rates and pressure yielded normalized RMSE values lower than 0.4 indicating that the sprayer performance can be efficiently predicted with the developed models. Additionally, experimental curve fitting results for the carrierchemical mix time constant and transport delay parameters from step changes of the chemical and carrierchemical flow rates yielded a statistic coefficient of determination R 2 close to 1 indicating that these DIS parameters can be efficiently predicted from experimental step responses.

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“…In reality, wrong field applications and spray drift account for 41% of all misapplications (29). This suggests that PF technologies coupled with educational thrusts/farmer mentoring, etc, can improve the efficiency of the current cpa delivery process.…”

Section: Site-specific Needsmentioning

confidence: 99%

“…The principle limitation here is the transport delivery between injection point and nozzle discharge. Alternatively, placement of chemical injection points close to the boom and nozzles significantly reduce transport delays and volume changes (29), but which requires special non-traditional pipe networks and connections. Control systems can be developed to anticipate rate changes/delays and/or make changes early but requires spatial/temporal/logistic solutions.…”

Section: Advances In Variable Rate Sprayersmentioning

confidence: 99%