Mechanical Seal Carbon Coating Against Silicate Deposition
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Solution Overview
Problem
Mechanical seals used in water-cooling engines and devices handling chemicals and oils face issues with deposition of silicate compounds on sealing faces, leading to loss of smoothness and leakage due to the high affinity of silicon carbide with silicate in the sealed fluid, which existing DLC coatings do not adequately address.
Innovation Solution
An amorphous carbon film with a silicon content of 1.5% or less is formed on the sealing faces of the seal rings using a hydrocarbon gas without silicon compounds, reducing the affinity with silicate and preventing deposition, while also incorporating a dynamic pressure generation mechanism to maintain low friction and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon carbide is used as the sliding material of the mechanical seal, then corrosion resistance and wear resistance are improved, but silicate compound deposition occurs on the sealing faces due to high affinity with silicate in the sealed fluid
Solution Approach 1:
The invention uses a composite structure consisting of a silicon carbide substrate material combined with an amorphous carbon film coating. The silicon carbide provides the base mechanical properties including corrosion and wear resistance, while the amorphous carbon film layer prevents silicate compound deposition by reducing affinity with silicate. This composite material approach allows both the beneficial properties of silicon carbide and the anti-deposition properties of amorphous carbon to work together.
Solution Approach 2:
The invention applies a localized amorphous carbon film coating specifically on the sealing faces where silicate deposition occurs, while the bulk silicon carbide material maintains its inherent corrosion and wear resistance properties. This local quality change addresses the deposition problem at the critical sealing surface without compromising the overall material performance.
2Ease of manufacture
If DLC coating is applied on sealing faces to improve wear resistance and machining property, then initial fitting between sealing faces is improved, but silicate compound deposition still occurs because existing DLC contains silicon
Solution Approach 1:
The invention changes the critical parameter of silicon content in the carbon film from the conventional DLC level (typically containing significant silicon) to an ultra-low silicon content of 1.5 at % or less. This parameter change fundamentally alters the chemical affinity properties of the coating, reducing its attraction to silicate compounds while maintaining the low friction and wear resistance characteristics of the carbon-based coating.
3Object-generated harmful factors
If amorphous carbon film with ultra-low silicon content is formed on sealing faces, then silicate compound deposition is prevented, but friction and leakage control must be maintained through dynamic pressure generation
Solution Approach 1:
The invention incorporates a dynamic pressure generation mechanism that utilizes the sealed fluid itself to generate hydrodynamic pressure between the sealing faces during relative rotation. This fluid pressure mechanism maintains the fluid film between sealing faces, ensuring low friction operation and preventing leakage, while the amorphous carbon film provides the low-friction surface necessary for effective fluid film formation.
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 amorphous carbon film effectively prevents silicate compound deposition on the sealing faces, maintaining smoothness and preventing leakage of the sealed fluid, even when using silicon carbide as the substrate material, and ensures the dynamic pressure generation mechanism functions without loss of performance.
Implementation Method 1
an amorphous carbon film formed by using a hydrocarbon gas containing no silicon compound is provided on at least any one of the sealing faces, and content of silicon of the amorphous carbon film is 1.5 at % or less
Implementation Method 2
a dynamic pressure generation mechanism between sealing faces by rotation, and sliding in a state where a liquid film is interposed, a so-called fluid lubrication state
Data Source
AI summary
In an exemplary embodiment, a sliding component includes an annular stationary side seal ring 5 fixed to the stationary side and an annular rotating side seal ring 3 to be rotated together with a rotating shaft, in which by relatively rotating opposing sealing faces S of the stationary side seal ring 5 and the rotating side seal ring 3, a silicate-containing sealed fluid present on one side in the radial direction of the relatively rotating sealing faces S is sealed, wherein an amorphous carbon film 8 formed by using a hydrocarbon gas containing no silicon compound is provided on at least any one of the sealing faces S of the stationary side seal ring 5 and the rotating side seal ring 3, and content of silicon of the amorphous carbon film 8 is 1.5 at % or less.