How Can We Delay The Aging Of The Sealing Ring?

Delaying the aging of sealing rings requires comprehensive measures from multiple dimensions, including material selection, optimization of operating environment, daily maintenance, and technological upgrades. The following are specific strategies and operational recommendations:
1, Material selection and adaptation
Select materials based on the characteristics of the medium
Oil resistant scenario: Prioritize the use of oil resistant materials such as nitrile rubber (NBR) and fluororubber (FKM/Viton).
High temperature resistance requirements: Fluororubber (FKM) and silicone rubber (VMQ) are used, among which FFKM can withstand high temperatures above 300 ℃.
Corrosion resistant environment: Use fluororubber and modified ethylene propylene rubber (EPDM) to avoid direct contact with strong acids and alkalis.
Low temperature environment: Choose silicone rubber (VMQ) or hydrogenated nitrile rubber (HNBR), whose low temperature brittleness temperature can reach below -60 ℃.
Improve aging resistance of materials
Additive optimization: Adding anti-aging agents (such as phenols and amines), UV absorbers (such as UV-9), and anti ozone agents (such as paraffin) to rubber formulations can extend material life by 20% to 50%.
Application of modified materials: using blending modification (such as EPDM/PP thermoplastic elastomers) or nanocomposite technology (such as adding nano-SiO?)? )Enhance heat resistance, chemical resistance, and mechanical strength.
2, Operating environment control
Temperature Management
Avoid overheating: During equipment operation, ensure that the medium temperature does not exceed the temperature resistance limit of the sealing ring material (such as NBR ≤ 120 ℃, FKM ≤ 200 ℃), and control the ambient temperature through a cooling system or insulation layer.
Reduce thermal shock: Avoid frequent and drastic temperature changes in the sealing ring (such as sudden increases from -20 ℃ to 150 ℃), and it is recommended that the temperature change rate be ≤ 5 ℃/min.
Pressure and medium optimization
Pressure adaptation: Ensure that the system pressure does not exceed 80% of the design pressure of the sealing ring. For example, when the design pressure of FKM sealing ring is 20MPa, the actual working pressure should be ≤ 16MPa.
Media filtration: Install a filter with a filtration accuracy of ≥ 50 μ m at the inlet of the media to prevent particle wear on the sealing surface.
Reduce chemical erosion
PH control: For rubber sealing rings, the pH value of the medium should be maintained within the range of 5-9; If contact with strong acid and alkali is required, PTFE or ceramic sealing rings should be used instead.
Isolation of corrosive media: Adopting a double sealed structure or adding isolation liquid (such as glycerin) to isolate the sealing ring from the corrosive media.
3, Installation and maintenance specifications
Installation process control
Cleaning operation: Before installation, clean the sealing groove and shaft surface with isopropanol or specialized cleaning agent to avoid oil stains and metal shavings residue.
Avoid mechanical damage: Use specialized tools (such as conical guides) for installation, and prohibit the use of sharp tools such as screwdrivers to pry and press. The installation torque should meet the material compression ratio requirements (usually 15%~30%).
Regular inspection and replacement
Rubber sealing ring hardness change ≥ 10 Shore A;
Continuous cracks or scratches with a depth of ≥ 0.5mm appear on the surface;
Compression permanent deformation rate ≥ 30% (NBR material).
Inspection cycle: Check every 3 months under high temperature and high pressure conditions, and every 6 months under normal conditions, with a focus on observing the wear, hardening, and cracking of the sealing surface.
Replacement standard: When the sealing ring encounters the following situations, it needs to be replaced immediately:
4, Dynamic monitoring and preventive maintenance
Intelligent monitoring technology
Leakage detection: Install a helium mass spectrometer leak detector (with a sensitivity of up to 10 µ Pa · m ³/s) or an ultrasonic leak detector to monitor the leakage rate at the sealing point in real time.
Vibration analysis: Monitor shaft vibration through vibration sensors. When the vibration amplitude exceeds 20% of the baseline value, check the alignment of the sealing ring.
Preventive maintenance strategy
Establish a lifespan record: record the sealing ring material, operating parameters, replacement time, and predict the remaining lifespan based on the material aging curve.
Redundant design: Key parts adopt a double O-ring series connection or O-ring+retaining ring combination structure to enhance fault tolerance.
5, Special working condition response plan
High speed rotation condition: Select low friction coefficient materials (such as PTFE coated rubber) or hydraulic balanced sealing structures, and control the linear velocity of the sealing surface to ≤ 15m/s.
Vacuum environment: Sealed with perfluoroether rubber (FFKM) or metal bellows to avoid a decrease in vacuum degree caused by gas leakage from the rubber sealing ring.
Radiation environment: High radiation scenarios such as nuclear power plants require the use of radiation resistant rubber (such as EPDM modified ethylene propylene rubber), or the use of mechanical seals and shielding layer structures.
Summary of Implementation Points
Priority material selection: Determine the material based on the three core parameters of medium, temperature, and pressure, choose FKM/FFKM for high temperature resistance, and PTFE for corrosion resistance.
Strict control conditions: temperature fluctuation ≤ 5 ℃/min, pressure ≤ 80% of design value, pH value 5-9.
Standard installation: Cleanliness ISO 14/11 level, compression rate 15%~30%, violent installation is prohibited.
Intelligent maintenance: Combining leak detection and vibration analysis, with dual safety design for critical areas.