Differential Pressure Sensor for Agricultural Sprayer Nozzle Blockage Detection
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Solution Overview
Problem
Existing methods for detecting blockages in agricultural sprayer nozzles are affected by the electrical resistivity of the dispersed fluid, leading to false positives and negatives, and do not provide information on individual nozzle conditions.
Innovation Solution
A device and method that compare the pressure within the nozzle to the pressure within the fluid conduit connected to it, using a differential pressure sensor and an electrical processing circuit to report a blockage when the pressure difference is below a predetermined threshold, independent of the fluid's electrical resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical current drop measurement is used to detect nozzle blockages, then blockage detection capability is provided, but false positives and negatives occur due to variations in fluid electrical resistivity
Solution Approach 1:
The patent replaces the electrical measurement system (current drop sensors) with a mechanical measurement system (pressure sensors). By measuring pressure differential across the nozzle instead of electrical current, the system eliminates the influence of fluid electrical resistivity variations, thereby resolving the contradiction between providing blockage detection capability and avoiding false positives/negatives.
2Reliability
If pressure difference across sprayer filter is measured to detect blockages, then blockage detection is provided, but no information on individual nozzle condition is obtained
Solution Approach 1:
The patent divides the measurement system into multiple independent pressure sensing points, each associated with a specific nozzle. By measuring pressure differential across each individual nozzle separately rather than measuring only the aggregate pressure difference across the entire filter, the system provides detailed information about the condition of each individual nozzle while maintaining reliable blockage detection capability.
3Measurement precision
If electrical resistivity compensation is implemented in current drop measurement system, then detection accuracy may be improved, but device complexity increases
Solution Approach 1:
The patent avoids increasing device complexity by completely replacing the electrical measurement approach with a mechanical pressure-based approach. This substitution eliminates the need for complex electrical resistivity compensation algorithms and additional electrical sensors, achieving high detection accuracy through a simpler mechanical measurement system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate detection of nozzle blockages without considering the fluid's electrical resistivity, suitable for applications with high pressure flow rates, reducing false alarms and improving precision in agricultural spraying.
Implementation Method 1
A first pressure is taken on the side of the filter closer to the liquid tank and a second pressure is taken on the side of the filter closer to the nozzles to determine a pressure difference
Data Source
AI summary
An agricultural sprayer arrangement includes a chassis, at least one ground engaging traction member carried by the chassis, a liquid tank carried by the chassis, a boom carried by the chassis, a fluid conduit associated with the boom that is fluidly connected to the liquid tank, a spray nozzle that is fluidly connected to the fluid conduit and includes a nozzle body, a differential pressure sensor with a first pressure sensor in the fluid conduit associated with the spray nozzle and a second pressure sensor in the nozzle body, and an electrical processing circuit coupled to the differential pressure sensor. The differential pressure sensor is configured to output a pressure difference signal and the electrical processing circuit is configured to report a blocked nozzle when the pressure difference signal is less than a predetermined threshold value.