Rotating Disk Spray Head for Agricultural Sprayer Flow Control
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Solution Overview
Problem
Traditional fixed orifice nozzles in agricultural sprayers require significant pressure changes to adjust flow rates for varying vehicle speeds, leading to compromised spray quality and high electrical current demands, with pulsing solenoid valves offering limited improvements due to slow response times and high coefficient of variation.
Innovation Solution
A spray head arrangement featuring a rotating disk with equi-angularly spaced openings controlled by a stepper motor to intermittently pulse fluid flow, maintaining constant pressure and adjusting flow rates based on vehicle speed, allowing for faster pulsing and reduced electrical current draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional fixed orifice nozzles change pressure to adjust flow rate for varying vehicle speeds, then flow rate adjustment is achieved, but spray quality deteriorates due to changes in atomization dynamics
Solution Approach 1:
The patent applies periodic action by using a rotating disk with multiple openings to intermittently allow fluid flow to the nozzle. The disk rotates to periodically align openings with the nozzle, creating pulsed flow at constant pressure. This resolves the contradiction by maintaining constant pressure (preserving spray quality) while adjusting the duty cycle of pulsing to control average flow rate.
2Manufacturing precision
If PWM technology uses solenoid valves to control nozzle flow rate while maintaining constant pressure, then spray quality is maintained, but electrical current draw becomes excessively high
Solution Approach 1:
The patent replaces the electrical solenoid valve system with a mechanically driven rotating disk system. The disk is rotated by a mechanical drive (such as a belt-driven motor or direct mechanical coupling to the vehicle's powertrain) to periodically align openings with the nozzle. This substitution eliminates the need for high-current electrical solenoid valves while maintaining constant pressure and controlling flow rate through the mechanical pulsing action.
3Manufacturing precision
If solenoid valves pulse flow to the nozzle at 10 Hz to improve coefficient of variation, then spray uniformity improves, but response time limitations prevent faster pulsing
Solution Approach 1:
The patent employs dynamics by using a rotating disk with multiple openings that can be driven at higher rotational speeds compared to solenoid valve actuation frequencies. The mechanical rotation allows for faster pulsing frequencies because there are no electromagnetic response time limitations. The multiple openings on the disk further enable higher effective pulse frequencies by allowing multiple flow passages per rotation cycle, thereby improving spray uniformity through faster pulsing.
4Device complexity
If traditional nozzles use fixed orifice geometry to control flow rate, then device complexity is reduced, but adaptability to varying vehicle speeds is compromised
Solution Approach 1:
The patent applies segmentation by dividing the flow control function into two separate components: a fixed orifice nozzle that maintains simple geometry, and a rotating disk with multiple openings that provides the adaptive flow modulation. The nozzle itself remains simple and fixed, while the rotating disk segment handles the speed compensation by periodically allowing flow through its openings. This segmentation preserves nozzle simplicity while adding adaptability through the separate rotating control mechanism.
Data Source
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AI summary
A spray head (12) is disclosed. The spray head (12) is adapted for being mounted along an agricultural sprayer spray boom with a plurality of like spray heads (12). The spray head (12) comprises: a spray head body (14) defining a cavity (90); a flow control member (32) being mounted in said cavity (90) for rotation about a fixed axis and containing a fluid passage arrangement; said body (14) being provided with a fluid inlet (16) and a fluid outlet (110), and said fluid passage arrangement being so located relative to said inlet (16) and outlet (110) that it intermittently establishes a flow path between said inlet (16) and outlet (110) during movement of said flow control member (32); a nozzle (26) coupled for receiving flow from said outlet; and a stepper motor (34) being coupled to said flow control member (32) for effecting movement of said flow control member (32) about said axis for intermittently establishing said flow path between said inlet (16) and outlet (110). Further, a sprayer with such spray head is disclosed.