Restructured PTFE filled with hollow glass microspheres is a unique material that combines good chemical resistance and high compressibility. Unlike traditional skived or molded PTFE, the restructured form minimizes creep while allowing the gasket to conform more easily to flange surfaces, especially under lower bolt loads. These properties are what make TEADIT Tealon® TF1570 a highly effective choice for demanding chemical sealing applications.

To ensure optimal sealing performance in complex applications, this guide outlines the steps for evaluating, selecting, and implementing the correct gasket material.

Step 1: Assess the Demands of the Sealing Environment

Before selecting any gasket material, operators and maintenance personnel should characterize the operational conditions of the application:

• Chemical media: Identify all process chemicals, especially strong acids, alkalis, and oxidizers. Determine the exposure to aggressive chemical media.
• Temperature and pressure ranges: Record both normal and peak conditions. Determine if the application requires high compressibility or low bolt loads.
• Flange construction: Determine if the flanges are composed of materials like glass-lined steel or plastic that are sensitive to high bolt loads or torque.
• Surface conditions: Check for unevenness, warping, or coating inconsistencies that may compromise the performance of traditional gaskets.

Step 2: Understand the Material’s Functional Advantages

Analyze the flange and operational parameters to identify whether traditional skived or molded PTFE gaskets struggle to conform or seal effectively. If sealing issues are observed, particularly with flange irregularities or a low available bolt load, consider how the material’s structure and fillers may impact gasket performance.

• Restructured PTFE matrix: Offers excellent chemical resistance without the creep or cold flow associated with virgin PTFE. It can be further enhanced with fillers.
• Glass microsphere filler: This is designed for high compressibility, allowing the gasket to conform to imperfect surfaces while maintaining seal integrity under lower bolt loads.
• Mechanical flexibility: This is especially beneficial in equipment that cannot withstand high seating stress.

Restructured PTFE is engineered for sealing in environments that challenge conventional materials. Its characteristics make it suitable for flanges that require sealing with minimal deformation or force, especially where mechanical loading must be carefully managed.

Step 3: Select the Optimal Gasket Material

Once the chemical application has been assessed, select a gasket material that is most suitable for the demands and requirements of the process media.

In applications with fragile or glass-lined flanges or where over-torquing is a risk, Tealon® TF1570 has proven to be most effective. Its restructured PTFE base with superior chemical resistance, glass microspheres that enhance compressibility and adaptability to flange surfaces, and mechanical integrity, which supports sealing performance with low bolt loads, make it an ideal choice for chemical processes.

Step 4: Calculate Bolt Load and Torque Precisely

Gaskets with PTFE and hollow glass microspheres should always be installed with controlled bolt loading:

• Perform torque calculations based on the material’s compressibility behavior
• Avoid applying too much load, especially with thin or coated flanges.
• Use a recommended torquing procedure (e.g. ASME PCC-1) to ensure even load distribution

Consult with Engineering for specific torque values and detailed assembly procedures. In applications with load limitations, TF1570’s ability to achieve a reliable seal at lower stress levels makes it a practical and efficient solution.

Step 5: Follow Best Practices for Installation and Monitor Performance

Successful gasket performance depends on proper installation:

1. Clean all flange surfaces thoroughly
2. Inspect for surface damage or irregularities
3. Align the gasket without applying stress or distortion
4. Tighten bolts following ASME PCC-1 recommendations to ensure uniform load distribution
5. In services where elevated temperatures are present, if possible, consider retorquing after a full thermal cycle Re-torque after initial thermal cycles, if required
6. Monitor for early signs of leakage during commissioning and record performance data over time

Avoid misalignment or uneven bolt load to maximize gasket life.

Final Thoughts

By selecting a gasket material engineered to adapt to flange irregularities, chemical attack, and variable loads, engineers can more effectively address persistent sealing issues. By following these steps, one can ensure the correct material selection, installation, and long-term performance in challenging chemical
applications.