Technical Manual for Correct Installation of Flange Gaskets: Practical Key Points from Selection to Leak Detection
The correct installation of flange gaskets is crucial for ensuring tight sealing and reliable operation of pipeline systems. Improper installation may lead to equipment failure, safety hazards, and costly downtime losses. This guide provides a detailed step-by-step installation process for flange gaskets and offers recommendations for selecting gasket types based on different application needs.
Step 1: Select the appropriate gasket types
Common types of flange gaskets include rubber gaskets, PTFE (polytetrafluoroethylene) gaskets, PTFE F4 rubber composite gaskets, metal spiral wound gaskets, oval gaskets, octagonal gaskets, pure fiber gaskets, and metal channel gaskets. Among them, metal spiral wound gaskets are the most widely used and will therefore be the focus of this introduction.
Metal spiral wound gaskets are semi-metallic sealing components specifically designed for flange connections under medium to high pressure and temperature conditions. Their manufacturing process involves alternately spirally winding V-shaped or W-shaped metal strips with flexible filler materials such as graphite or polytetrafluoroethylene (PTFE). This structure endows them with excellent elasticity and sealing performance. Depending on specific application requirements, inner and/or outer rings can be added to further enhance the stability and sealing effectiveness of the gasket.
Step 2: Clean the flange surface
Contaminants such as rust, old gasket residue, or oil stains can damage the sealing effect and cause leaks. Please follow the steps below to properly clean:
Use a wire brush or plastic scraper to remove impurities (avoid using metal tools to prevent scratching the flange surface).
Degrease the surface using acetone or a suitable industrial solvent.
Check the flange for any damage: If the flange is warped or scratched, it must be repaired before installation.
Expert tip: According to data from the Fluid Sealing Association (FSA), 70% of flange leakage issues stem from improper surface pretreatment.
Step 3: Precisely position flange gaskets
Align the center of the gasket with the flange hole, and then gently place the gasket between the two flanges.
Unless specifically required by the gasket manufacturer, glue or adhesive should not be used.
For gaskets with locating rings, it is necessary to ensure that the locating rings are accurately embedded into the flange groove.
Importance note: As pointed out by the journal "Pump & System", gasket positioning deviation can lead to uneven compression, which in turn directly causes leakage.
Step 4: Bolt installation and tightening
Insert the bolts into the flange holes in diagonal order (this method ensures even pressure distribution).
Tighten the nut gently to secure the gasket, but do not apply the final torque at this time.
Using a torque wrench, gradually tighten the bolts in a crosswise sequence in stages: first apply 30% of the recommended torque, then 60%, and finally reach 100%.
Best practices supported by data: Research published in the International Journal of Pressure Vessels and Piping indicates that proper bolt tightening can reduce the risk of leakage by 90%.
Step 5: Conduct leakage detection
Leakage can be detected using either air pressure testing (by observing bubbles) or water pressure testing (by checking for drips), both of which allow for the direct identification of leakage points.
For leaks that are highly concealed and difficult to detect directly, ultrasonic detection equipment can be used.
Conclusion
The correct installation of flange gaskets is crucial for ensuring system safety, operational efficiency and cost-effectiveness. If you require high-quality gaskets (including rubber gaskets, PTFE gaskets, PTFE F4 rubber composite gaskets, metal spiral wound gaskets, oval gaskets, octagonal gaskets, pure fiber gaskets, and metal groove gaskets), please contact us.
