Conductive Vane Negative Pressure Pump
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Solution Overview
Problem
The existing negative pressure pump designs, such as Japanese Patent No. 4,600,654, face issues with electrical charging due to frictional electrification between the housing and vane end portions made of different materials, leading to potential electrostatic discharges and operational inefficiencies.
Innovation Solution
A negative pressure pump with an electrically insulative casing and a conductive vane, where the vane is supported by a conductive rotary shaft that is earthed, allowing static electricity to dissipate, and the vane is formed entirely of conductive resin with adjustable conductivity using fillers for improved abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the housing and vane end portions are formed of different materials, then the structural design flexibility is improved, but frictional electrification occurs during operation
Solution Approach 1:
The vane is formed entirely of resin material, making it homogeneous with the housing. This eliminates the material interface between housing and vane end portions, thereby preventing frictional electrification while maintaining structural design flexibility through resin formulation and additive technologies.
Solution Approach 2:
The invention uses composite resin materials with conductive fillers (such as carbon black, metal powders, or conductive polymers) to create a vane that is both electrically conductive and mechanically robust. This composite approach allows the vane to dissipate static electricity while maintaining the benefits of resin-based construction.
2Reliability
If the vane is formed of metal material to improve conductivity, then electrical charging is suppressed, but fabrication complexity and cost increase
Solution Approach 1:
The vane is formed of resin containing conductive fillers such as carbon black, metal powders, or conductive polymers. This composite material approach provides sufficient electrical conductivity to suppress charging by frictional electrification while maintaining the manufacturing advantages of resin molding, including ease of forming complex geometries and integration with the housing.
Solution Approach 2:
The electrical conductivity of the vane is controlled by adjusting the type, amount, and distribution of conductive fillers in the resin matrix. This parameter adjustment allows optimization of conductivity to suppress frictional electrification while maintaining manufacturability and cost-effectiveness.
3Strength
If the casing is formed of metal material to improve durability, then strength is improved, but fabrication cost increases
Solution Approach 1:
Both the housing and vane are formed of resin material, creating a homogeneous material system throughout the pump assembly. This eliminates the need for expensive metal components while maintaining sufficient strength and durability through proper resin formulation, reinforcement, and molding techniques.
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 effectively suppresses frictional electrification, reduces electrostatic discharges, and lowers fabrication costs while maintaining operational efficiency, including reduced driving resistance and energy loss in low-temperature conditions.
Implementation Method 1
because the housing (a casing) and the vane end portions are formed of different materials, the housing and the vane end portions are electrically charged by frictional electrification during operation of the negative pressure pump
Implementation Method 2
the vane being electrically connected to the power source via the rotary shaft, the vane rotating integrally with the rotary shaft and end portions of the vane sliding over an inner wall face of the casing
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A negative pressure pump (10) includes an electrically insulative casing (20), an electrically conductive rotary shaft (40) and an electrically conductive vane (50). The casing (20) is formed in a tubular shape, an axial direction one end of which is closed off by a cap body (34). The rotary shaft (40) is disposed in the casing (20), is mechanically and electrically connected to an earthed power source, and is rotated by power being transmitted from the power source. A rotation center of the rotary shaft (40) is disposed to be offset relative to a center of the casing (20). The vane (50) is disposed in the casing (20), is supported at the rotary shaft (40) to freely reciprocate in a direction orthogonal to the rotary shaft (40), and is electrically connected to the power source via the rotary shaft (40). The vane (50) rotates integrally with the rotary shaft (40), and end portions (50B) of the vane slide over an inner wall face (inner periphery face (22A)) of the casing. The vane (50) divides the interior of the casing (20) into a plurality of spaces and generates negative pressure.