Vacuum Pump Sliding Layer with Anodized Oxide and Fluoropolymer Seal
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Solution Overview
Problem
Vacuum pumps face challenges with sealing effectiveness due to media reaction with fluid seals, leading to contamination and reduced end pressures, and existing dry solutions suffer from high wear and limited service life of sliding seals.
Innovation Solution
A vacuum pump design featuring a sliding layer with an oxide layer covered or impregnated by a fluorine-containing polyurethane seal, which enhances tribological performance, protects against wear, and improves gas tightness by sealing pores in the oxide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sliding or rubbing seals made of chemically resistant materials are used in dry solutions, then media contamination is prevented, but wear resistance is poor and service life is limited
Solution Approach 1:
The patent applies a composite structure consisting of a base material (metal or plastic) combined with a ceramic coating layer (such as aluminum oxide, titanium oxide, or silicon oxide). This composite structure provides both the chemical resistance of the base material and the exceptional wear resistance of the ceramic coating, thereby extending seal service life while maintaining compatibility with pumped media.
Solution Approach 2:
The patent modifies the surface properties of the seal by applying ceramic coatings with specific hardness values (typically 15-20 GPa), fracture toughness, and surface roughness parameters. These parameter changes enable the seal to withstand high contact pressures and abrasive wear while maintaining dimensional stability and sealing performance throughout extended service life.
2Reliability
If oxide layers are applied to reduce wear, then wear resistance is improved, but gas tightness is insufficient due to porous structure
Solution Approach 1:
The patent utilizes the controlled porous structure of anodized oxide layers as a functional feature rather than a defect. The porous structure is subsequently filled or sealed with appropriate materials (such as resins, metals, or additional coating layers) to eliminate gas permeability while preserving the wear-resistant surface structure. This approach maintains the benefits of the porous oxide layer for wear protection while eliminating gas leakage pathways.
Solution Approach 2:
The patent introduces intermediary sealing elements or coating layers between the porous oxide layer and the pumped medium. These intermediaries (such as PTFE coatings, resin impregnation, or metal infiltration layers) fill the pores and provide a gas-tight barrier while allowing the underlying oxide layer to maintain its wear-resistant function.
3Productivity
If heating is applied to improve running-in times and final pressures, then performance is improved, but energy consumption increases and process complexity increases
Solution Approach 1:
The patent applies ceramic coatings and surface treatments during the manufacturing process before the pump enters service. This preliminary action establishes optimal surface properties (hardness, smoothness, porosity control) that enable immediate efficient operation without requiring extended running-in periods. The surface is pre-conditioned to minimize initial wear and maximize sealing performance from startup.
Solution Approach 2:
The patent replaces thermal processing (heating) with mechanical and chemical surface engineering approaches. By using ceramic coatings, anodization, and surface texturing during manufacturing, the patent achieves optimal running-in characteristics through mechanical means rather than thermal treatment, thereby eliminating energy consumption and process complexity associated with heating.
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 solution achieves lower ultimate pressures and shorter running-in times while maintaining high wear resistance and preventing gas flow through the oxide layer's defects, resulting in improved sealing and extended service life.
Implementation Method 1
Such sliding layers can comprise an oxide layer formed by anodic oxidation in an acidic electrolyte, in particular one containing oxalic acid, sulfuric acid or mixtures thereof
Implementation Method 2
the oxide layer being at least partially covered by the seal and/or impregnated with the seal
Data Source
AI summary
A pump, in particular a vacuum pump, comprising a sliding layer (152), wherein the sliding layer comprises an oxide layer, in particular formed by anodic oxidation in an acidic electrolyte, and a polymer-based sealant, in particular based on a fluorine-containing polymer, and wherein the oxide layer is at least partially covered by the sealant and/or impregnated with the sealant. A method for producing a sliding layer (152) comprising the following steps: a) producing an oxide layer, in particular by anodic oxidation, in an electrolyte, preferably containing oxalic acid; and b) coating the oxide layer with a sealant.