Electrostatic Spray Device with Intermediate Electrode
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Solution Overview
Problem
Existing electrostatic spraying technologies face challenges with conductive coating products, particularly hydrosoluble ones, as they require complex isolation methods to prevent short-circuiting, and are sensitive to environmental conditions and dirtying issues, especially when using 'internal' or 'Corona' charge modes.
Innovation Solution
An electrostatic sprayer with a rotating bowl and multiple electrodes, including a first ionizing charge electrode, a second transport electrode, and a third stabilizing electrode at an intermediate potential, positioned to effectively charge and steer droplets towards a target while avoiding field line closure and minimizing dirtying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal charge mode is used, then deposition performance is improved and dirtying is reduced, but device complexity increases due to isolation requirements
Solution Approach 1:
The patent introduces a third electrode at intermediate potential between the high-voltage ionizing electrode and the earth-potential transport electrode. This intermediate electrode acts as a mediator that prevents direct field line closure, eliminates the need for complex isolation systems, and maintains the benefits of internal charging mode for conductive coating products.
2Ease of operation
If external Corona charge mode is used, then coating product can be kept at earth potential, but sensitivity to environmental conditions and dirtying increases
Solution Approach 1:
The patent merges the advantages of both internal and external charge modes by combining an ionizing electrode (for effective charging) with a transport electrode at earth potential (for environmental stability). The third intermediate electrode ensures that field lines do not close on the ionizing electrode, thereby reducing dirtying while maintaining ease of operation.
3Reliability
If field lines close on charge electrode, then charging is achieved, but effectiveness of charge and transport decreases
Solution Approach 1:
The patent segments the electrostatic field into distinct zones by introducing a third electrode at intermediate potential. This creates separate charging and transport fields, preventing field line closure and ensuring that charging and transport functions are performed independently and efficiently without interfering with each other.
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 configuration allows for efficient electrostatic charging and transport of droplets towards a coated object, maintaining the coating product at earth potential and reducing the complexity and sensitivity issues associated with previous charge modes.
Implementation Method 1
at least one first ionizing charge electrode for charging droplets of coating product
Implementation Method 2
at least one second electrode for creating an electrostatic field to transport droplets toward an object to be coated
Data Source
AI summary
An electrostatic spray device for spraying a liquid coating product, including a rotating bowl and a device for driving the bowl around a rotational axis, the bowl defining a concave surface for distributing the coating product and an edge which limits an area for the spraying the coating product. The spray device includes an electrode that charges by ionization of drops of the coating product. The electrode is arranged, in relation to the edge and along the rotational axis, opposite the spray area, between the edge and the device for driving the bowl. A second electrode mounted on a stationary body allows the creation of an electrostatic field for transporting drops. A third electrode, which is also mounted on a stationary body, is brought to an intermediate potential between those of the first and second electrodes during the operation of the spray device.