Air Duster Throttle Geometry for Proportional Airflow Control
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Solution Overview
Problem
The existing air duster structures for driving tools, which rely on externally supplied compressed air, face operability issues due to a decrease in air flow pressure difference as the operation button is pressed further, leading to a diminished change in air jetted out, affecting the tool's usability.
Innovation Solution
The air duster structure incorporates a flow amount adjustment mechanism with a throttle portion designed in a tapered shape, allowing the flow channel area to increase more rapidly than proportionally with operation, compensating for the pressure difference decrease by expanding the clearance, maintaining a proportional relationship between operation amount and air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the release valve or pipe line is formed in a tapered shape to increase the flow channel area according to the pushing amount, then the operability is improved when the flow amount gradually increases proportionally, but the pressure difference becomes small when the flow amount increases, causing the change in flow amount to diminish
Solution Approach 1:
The patent changes the geometric parameters of the throttle portion from a simple tapered shape to a composite shape with multiple sections having different taper ratios. The first section has a larger taper ratio while the second section has a smaller taper ratio, allowing different rates of flow channel area expansion at different operation stages to maintain proportional relationship between operation amount and air flow amount throughout the full range of motion.
Solution Approach 2:
The throttle portion is segmented into multiple sections (first and second sections) with different geometric characteristics. Each section handles a different range of operation amounts, with the first section managing the initial range and the second section managing the subsequent range, allowing optimized control over the entire operation range.
2Ease of operation
If the flow channel area is increased to maintain proportional relationship between operation amount and air flow amount, then the operability is improved, but the pressure difference decreases making further adjustment ineffective
Solution Approach 1:
The patent applies parameter changes by varying the taper ratio along the length of the throttle portion. The first section uses a larger taper ratio to generate sufficient pressure difference at lower operation amounts, while the second section uses a smaller taper ratio to maintain proportional flow increase at higher operation amounts when pressure difference naturally decreases.
Solution Approach 2:
The throttle portion is designed with dynamic characteristics where the rate of area expansion changes along its length. This dynamic geometry allows the system to adapt to the changing pressure conditions as the operation button is pressed, maintaining effective control throughout the full range of motion.
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
This design ensures a consistent and proportional increase in air flow from the nozzle, enhancing operability by maintaining a significant air output even when the operation button is pressed fully, thus improving the tool's performance.
Implementation Method 1
as the flow amount of the air being jetted out increases, the pressure in the accumulator provided on the upstream side of the release valve decreases and the difference in the pressure between in front of and behind the throttle of the release valve becomes small
Implementation Method 2
it is considered to form the release valve or a pipe line in a tapered shape to increase the area of the flow channel of the air according to the pushing amount of the operation button
Data Source
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AI summary
An air duster structure that is configured to jet compressed air out of a nozzle, includes a flow amount adjustment mechanism which is configured to adjust an amount of air jetted out of the nozzle. The flow amount adjustment mechanism includes: a pipe line for circulating air; a valve member disposed inside the pipe line and being movable; and a throttle portion configured to gradually change an area of a flow channel in which air circulates, with a movement of the valve member, to control a flow amount of the air in the pipe line. The throttle portion is structured so as to increase the area of the flow channel at an accelerated rate when the valve member moves in a direction that opens the pipe line.