Electrostatic Conveyor-Wheel Powder Feeder for Low-Flow Accuracy
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Solution Overview
Problem
Existing powder metering devices for metal additive manufacturing, welding, and cladding face issues such as high gas flow requirements, complexity, cost, incompatibility with vacuum processes, and pulsations in powder flow, especially at low flow rates, which are not adequately addressed by current conveyor-disc, auger-type, or electrostatic feeders.
Innovation Solution
A conveyor powder feeder utilizing electrostatic oscillation to evacuate powder from a rotating wheel rim, allowing for consistent powder flow at low or zero gas flow rates, combined with an optional gas jet mechanism for enhanced performance across a range of flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conveyor-disc powder metering devices are used, then smooth and accurate powder flow is achieved, but significant gas flow is required which increases complexity and cost
Solution Approach 1:
The patent replaces the pneumatic suction system with an electrostatic field system. Instead of using gas flow to evacuate powder from the conveyor disc groove, an electrostatic field is applied to remove residual powder, eliminating the need for complex gas flow control systems while maintaining accurate powder metering.
Solution Approach 2:
The patent eliminates the pneumatic system entirely by using electrostatic forces to clear the groove. The high-voltage electrode creates an electrostatic field that attracts and removes residual powder from the groove, replacing what would traditionally require a pneumatic suction system.
2Manufacturing precision
If conventional conveyor-disc feeders are used, then powder metering is achieved, but they are not compatible with vacuum processes
Solution Approach 1:
The patent replaces the gas-based evacuation mechanism with an electrostatic field system that operates independently of atmospheric conditions. The electrostatic field can function effectively in vacuum environments, enabling compatibility with vacuum powder feeders while maintaining accurate metering.
3Device complexity
If auger-type powder feeders are used, then gas-free operation is achieved, but periodic pulsations occur in powder flow
Solution Approach 1:
The patent uses electrostatic forces to create oscillating motion of powder particles as they are cleared from the groove. This electrostatic oscillation provides continuous, smooth powder flow without the periodic pulsations characteristic of auger-type feeders, while operating without gas flow.
4Loss of energy
If perforated-disc type powder feeders are used, then gas consumption is reduced, but pulsations occur at low flow rates
Solution Approach 1:
The patent replaces the gas-based evacuation system with electrostatic field-based powder removal. This eliminates gas consumption entirely while providing smooth, consistent powder flow at all flow rates through the electrostatic oscillation mechanism, avoiding the pulsations that occur with perforated disc feeders at low flow rates.
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
The electrostatic conveyor powder feeder provides smooth and consistent powder flow at low flow rates, reducing gas consumption and complexity while maintaining the precision of conveyor-disc feeders, and accommodating both high and low flow rates with improved stability and accuracy.
Implementation Method 1
The electric field created within the space causes the powder particles falling onto the powder landing surface and rotating under the electrode to develop an electrical surface charge and be subject to an electrostatic force that causes the powder particles to oscillate between the pile and the insulator
Implementation Method 2
gravity acting upon the powder particles within the hopper causes the powder particles to fall upon the powder landing surface and create a pile of powder particles on the powder landing surface
Data Source
AI summary
A powder feeder includes a hopper holding powder particles and a rotating conductive wheel having a rim. The rim has a powder landing surface in a groove in the rim. As the wheel rotates, the powder landing surface is disposed below the hopper. A voltage supply electrically communicates with an electrode and the wheel. The electrode and powder landing surface have a space between them. An insulator is disposed between the electrode and the wheel. The voltage supply produces an AC electric potential between the electrode and the rim that creates an alternating electric field within the space. An outlet chamber is positioned below the wheel. The electric field created within the space causes powder particles falling onto the powder landing surface and rotating under the electrode to develop an electrical surface charge. An electrostatic force causes powder particles to oscillate between the pile and the insulator. After a period of oscillation the particles drop over the edges of the rim and into the chamber.