What problems will occur when the sealing ring is intolerant to water vapor?

If the sealing ring is intolerant to water vapor, it will experience accelerated aging, deterioration of physical properties, and sealing failure in a high-temperature and water-vapor environment. In severe cases, it may even cause equipment failures and safety hazards. The specific manifestations are as follows:

1. Accelerated material aging

Thermal oxidative aging: High-temperature water vapor accelerates the thermal oxidative aging process of the sealing ring material, causing molecular chain breakage and cross-linking, and transforming the soft and elastic sealing ring into a hardened and brittle one. For example, EPDM (terpolymer ethylene propylene diene monomer) sealing rings in 80°C chlorine-containing water have an aging rate 2-3 times faster than in clean water, and leakage may occur within 3-5 years.

Hydrolysis reaction: Active water molecules in water vapor react with chemical bonds such as ester bonds and ether bonds in the rubber, especially at 300°C, significantly accelerating the reaction rate, resulting in a decrease in material strength and loss of elasticity. For example, rubber containing ester bonds will have its molecular chains cut off in high-temperature water vapor, causing a sharp deterioration in material performance.

2. Physical performance degradation

Swelling and dissolution: The sealing ring material may swell, become sticky, or dissolve due to water vapor penetration. For example, nitrile rubber (NBR) expands by 300% in contact with kerosene, eventually cracking and leaking; in high-temperature water vapor, ordinary rubber may also fail in sealing due to swelling.

Cracking and fracture: In low-temperature environments, sealing rings that are not tolerant to water vapor may crack due to cracking. For example, EPDM sealing rings may crack at -40°C, causing leakage in the automotive radiator; at extremely low temperatures (below -60°C), silicone rubber sealing rings may also crack, requiring the use of specialized low-temperature elastic materials (such as perfluoroether rubber).

3. Sealing failure and leakage

Sealing pressure attenuation: After aging, the sealing ring undergoes increased permanent deformation upon compression, unable to return to its original state upon pressure application, resulting in continuous attenuation of sealing pressure. When the attenuation reaches a point where it cannot resist the internal pressure of the pipeline, dripping and leakage will occur. For example, EPDM sealing rings in 80°C hot water pipes are prone to this problem after 3-5 years.

Sealing structure damage: High-temperature water vapor may cause the sealing ring to come out of the compression groove or repeatedly shift due to temperature fluctuations, damaging the original sealing contact position and forming new leakage channels. For example, in the medium- and high-temperature range, the sealing ring undergoes repeated displacement due to thermal expansion and contraction, potentially leading to the complete failure of the sealing system.

4. Equipment failure and safety hazards

Leakage in high-pressure steam pipelines: In high-pressure steam pipelines, water vapor penetrates into the molecular chain gaps of the rubber sealing components, causing degradation phenomena such as swelling, chemical bond breakage, etc., resulting in sealing failure and even jet-like leakage, endangering equipment safety.

Failure of sterilization equipment: In high-pressure sterilizers, aging or damage to the sealing ring may lead to steam leakage, insufficient pressure, and even sterilization failure, affecting experimental results or product quality. For example, a failure of the sealing ring may cause the sterilization process to run normally but result in substandard test results.

5. Shortened lifespan and increased maintenance costs

Temperature fluctuation impact: Frequent temperature fluctuations (such as daily start-stop of hot water equipment or seasonal temperature differences in outdoor pipelines) accelerate the fatigue damage of the sealing ring, reducing its lifespan by 20%-30% compared to a constant medium-temperature environment. For example, an EPDM sealing ring with a lifespan of 25 years in a constant environment may only last 17-20 years in fluctuating conditions.

Medium synergy aging: If the pipeline contains chloride ions (such as residual from water disinfection) or weak acids and bases, medium-temperature conditions accelerate the erosion of the sealing ring by the medium, further shortening the sealing lifespan. For example, EPDM ages 2-3 times faster in 80°C chlorine-containing water than in clean water.

Recommendations for countermeasures

Material matching: Select sealing ring materials that are resistant to water vapor based on the working conditions, such as EPDM (terpolymer ethylene propylene diene monomer) suitable for weakly acidic media, FPM (fluorine rubber) suitable for strongly acidic media, and FFKM (perfluoroether rubber) suitable for 300°C high-temperature water vapor environments.

Working condition control: Install temperature control valves, add insulation layers to the pipelines (to reduce the influence of environmental temperature differences), and use buffer tanks (to avoid sudden temperature increases and decreases in the medium), reducing the fatigue damage of the sealing ring. Regular inspection and replacement: For pipelines operating in high-temperature and fluctuating temperature environments, inspect the interfaces for any leakage signs every 1-2 years. Replace the aging sealing rings promptly to prevent the complete failure of the sealing system.

FOREVER SEALS! Seals manufacturer, accept custom seals, from design to research and development, from production to testing, a full range of services. For more information, please contact FOREVER SEALS directly. FOREVER SEALS product experts are here to help you! Whatsapp: +86-18098184099；WeChat: +86-13049188460；  E-mail: sales@foreverseals.com.