Spray Gun Piston Position Sensor Valve Control
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Solution Overview
Problem
Existing spray guns face challenges in maintaining a coherent spray jet and preventing fluid dripping during the ejection of crop protection agents, particularly when the piston pressure drops at the end of the ejection process, causing the fluid jet to break off and miss the target area.
Innovation Solution
A spray gun design featuring a fluid valve and sensor system that detects the piston's position using a magnetic field, ensuring the fluid valve closes when maximum pressure is still being exerted, maintaining consistent ejection velocity and preventing fluid from escaping after the ejection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston pressure is maintained throughout the ejection process, then the fluid jet remains coherent and reaches the target area, but the device complexity increases due to the need for sensor and valve control systems
Solution Approach 1:
The fluid valve is closed preliminarily when the piston reaches a defined position before the pressure drops, preventing the harmful effect of pressure drop on spray coherence. This advance action ensures the spray jet remains coherent without requiring continuous pressure maintenance throughout the entire piston stroke.
Solution Approach 2:
A sensor detects the piston position and provides feedback to control the fluid valve timing. This feedback mechanism allows the system to automatically close the valve at the optimal moment when the piston reaches a defined position, maintaining spray coherence without manual intervention or complex continuous pressure control.
2Productivity
If the ejection process continues until the piston reaches the end position, then the fluid chamber is completely emptied, but the fluid jet breaks off and misses the target area due to pressure drop
Solution Approach 1:
The fluid valve is closed in advance when the piston reaches a defined position, preventing the pressure drop that would cause the spray jet to break off. This preliminary anti-action stops the ejection process before the harmful pressure drop occurs, maintaining spray jet accuracy while still achieving effective fluid delivery to the target area.
3Device complexity
If the fluid valve remains open throughout the piston movement, then the device structure is simpler, but fluid drips after ejection due to pressure drop
Solution Approach 1:
The fluid valve is closed preliminarily when the piston reaches a defined position, preventing fluid dripping before it can occur. This advance closure eliminates the harmful dripping effect while maintaining a relatively simple valve control system that only needs to respond to a single piston position threshold.
4Speed
If the piston moves quickly to maintain high ejection velocity, then the spray reaches the target area effectively, but the pressure drops before the piston reaches the end position, causing spray interruption
Solution Approach 1:
The fluid valve is closed in advance when the piston reaches a defined position, preventing the pressure drop that would interrupt the spray jet. This allows the piston to move quickly and maintain high ejection velocity throughout the productive phase of the stroke, while the preliminary valve closure ensures continuous spray jet reliability by stopping ejection before pressure collapse occurs.
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
Ensures a coherent fluid jet reaches the target area without dripping, maintaining consistent ejection speed and preventing unwanted fluid contact, even with viscous crop protection agents.
Implementation Method 1
The sensor (29) is designed in such a way that a defined position of the piston (2), at which there is still fluid in the fluid chamber (3) during the ejection process, can be detected by means of a magnetic field generated or changed by the piston (2)
Implementation Method 2
A fluid received by the fluid chamber (3), which is pushed out of the fluid chamber (3) through the first cylinder port (5) by the pressure exerted by the piston (2)
Data Source
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AI summary
The invention relates to a spray gun for expelling a fluid, comprising at least one cylinder (1) in which a piston (2) is movably mounted. A fluid chamber (3) is formed in the cylinder (1), the volume of said chamber being changeable by a movement of the piston (2) and at least one first cylinder opening (5) being formed in said chamber. The spray gun also comprises a spray opening which is connected to the first cylinder opening (5) of the cylinder (1) via a connecting line (20) so that a fluid which is held in the fluid chamber (3) and which is pushed through the first cylinder opening (5) by the pressure exerted by the piston (2) reaches the spray opening via the connecting line (20) and is expelled at said spray opening. The spray gun according to the invention is characterized in that a fluid valve (21) lies in the connecting line (20), and the cylinder (1) is equipped with a sensor (29) with which a defined position of the piston (2) can be detected, fluid still being located in the fluid chamber (3) during the expelling process in said position, and with which the fluid valve (21) can be actuated. The fluid valve (21) is closed by means of the sensor (29) if the defined position of the piston (2) has been detected. The invention further relates to the use of such a spray gun for expelling pesticides.