Powder Feed Unit Using Carrier Gas for Smooth Low-Flow Dosing
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Solution Overview
Problem
Existing powder feed units for laser welding and thermal spraying processes have complex constructions that lead to congestion, interruptions, and pulsations, particularly at low carrier gas flow rates, and are difficult to manage and clean.
Innovation Solution
A simplified powder feed unit design with a housing, container, and actuator that uses a carrier gas overpressure to facilitate smooth powder collection and dosing, reducing contact with internal surfaces and eliminating the need for blade wheels and rotating brushes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of parts (discs with drop holes, blade wheels, rotating brushes) are used to collect and dose powder particles, then the powder collection and dosing function is achieved, but the risk of congestion and interruptions increases, and the system becomes difficult to manage and clean
Solution Approach 1:
The patent extracts and removes the complex mechanical dosing components (blade wheels, rotating brushes, discs with drop holes) from the powder feed system. Instead, it uses a simplified design where pressurized carrier gas directly fluidizes and transports powder particles through a smooth bore conduit, eliminating the parts that cause congestion and are difficult to clean.
Solution Approach 2:
The patent applies pneumatic principles by using pressurized carrier gas to fluidize the powder stock and transport it through the feed unit. The gas pressure creates a fluidized bed that allows smooth, continuous powder flow without mechanical moving parts, resolving the contradiction between reliability and device complexity.
2Productivity
If high overpressure control (0.5MPa to 0.8MPa) is used to collect and dose powder particles, then the powder dosing function is achieved, but pulsations occur and the system does not work well at low flow rates
Solution Approach 1:
The patent changes the pressure parameter control approach by using a pressure regulator to maintain a relatively low and stable overpressure (0.02MPa to 0.2MPa) instead of high overpressure. This parameter change eliminates pulsations and enables stable operation at low flow rates while maintaining consistent powder dosing.
3Object-affected harmful factors
If a low flow rate of carrier gas is used, then turbulence in gas flows is limited or prevented, but many existing systems cannot maintain smooth powder flow
Solution Approach 1:
The patent uses pneumatic fluidization principles where the carrier gas flow rate is carefully controlled to maintain the powder in a fluidized state without causing turbulence. The smooth bore conduit design配合with controlled gas flow ensures laminar flow conditions while maintaining reliable powder transport.
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 design achieves consistent powder flow, reduces pulsations, and simplifies maintenance and cleaning, enhancing the performance and user experience of laser welding and thermal spraying processes.
Implementation Method 1
a powder collect-and-load cavity that is arranged in fluid communication with the first passageway for allowing the carrier gas to enter the powder collect-and-load cavity
Implementation Method 2
a wall portion that is configured and arranged to allow at least a portion of the powder particles of the powder stock upon passing through the second passageway to freely fall into the powder collect-and-load cavity and to be loaded onto the carrier gas
Implementation Method 3
the housing being configured to contain the carrier gas in use of the powder feed unit at a pressure that is higher than a pressure of an environment in which the housing is positioned
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The invention relates to a powder feed unit (1) comprising a powder collection unit (10) that comprises a surface covering part (10a) and a powder collect-and-load part (10b) that allow a carrier gas (6) to enter a powder collect-and-load cavity (13) of the powder collect-and-load part via a first passageway (12), and powder particles to freely fall into said cavity via a second passageway (14). Upon entering said cavity, the powder particles are loaded onto the carrier gas thereby reducing and ideally avoiding contact between the powder particles and interior surfaces of said cavity. The carrier gas that is loaded with the powder particles can exit said cavity via a third passageway (17) that is fluidly connected with a tubular conveyor element (18). The invention also relates to an apparatus (3) for performing laser welding processes or thermal spraying processes that comprises the powder feed unit according to the invention.