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On-Site Machining of Lens Ring Flange Faces at 20° Using FI26
MT Portable Machine – Field Repair Case Study
Last week, the MT Portable Machine technical team successfully completed an on-site machining project involving multiple lens ring flange faces for a client, using our FI26 portable flange facing machine. The job required precision machining of 20° conical sealing surfaces, making it both a challenging and rewarding field machining assignment.
Lens Ring Gasket and Flange Sealing Principle
Lens ring gaskets are widely used in high-pressure pipeline systems due to their excellent sealing reliability and reusability. The sealing effect is achieved primarily through elastic deformation of the gasket surface rather than plastic deformation. This design makes lens gaskets highly resistant to overloading.
In a typical lens ring gasket flange joint, the gasket sealing surface is spherical (arc-shaped), while the flange groove is conical, forming a cone-to-sphere metal-to-metal seal. As the bolt load increases, the contact area between the spherical lens surface and the conical flange groove enlarges, reducing the rate of increase in unit compressive stress and improving joint stability.
The lens ring gasket used in this project complies with:
1. DIN 2696-1972 (Lens Ring Gasket, Type 50-L)
2. Applicable flange standard: DIN 2628
3. Typical application: steel pipe flange connections in high-pressure service
On-Site Flange Face Machining Challenges
The client required in-situ refurbishment of lens ring flange sealing surfaces without dismantling the pipeline. Key machining requirements included:
1. Accurate restoration of the 20° conical sealing angle
2. High surface finish suitable for metal-to-metal lens gasket sealing
3. Strict concentricity and flatness control
4. Minimal downtime at site
Using the FI26 flange facing machine, the MT team performed OD-mounted on-site machining, ensuring stable alignment and consistent cutting accuracy. The FI26’s rigid structure and precise feed control allowed smooth machining of the conical flange grooves, fully restoring the sealing geometry to specification.
Results and Client Feedback
The refurbished lens ring flange faces met all technical requirements for DIN lens gasket sealing, ensuring reliable reassembly and leak-free operation. This first collaboration with the client successfully demonstrated both the machining capability of MT Portable Machine equipment and the field expertise of the MT technical team.
About MT Portable Machine
MT Portable Machine specializes in portable machining solutions, including flange facing, line boring, milling, and in-situ repair for pipeline and pressure equipment maintenance worldwide. Our machines are designed for precision, reliability, and field efficiency.
Technical Support
If you are facing on-site machining challenges, flange sealing issues, or need the latest product specifications and technical solutions, please contact MT Portable Machine’s technical team. We are ready to support your field service requirements.
www.mtportable.com
Jichuang Machinery Manufacturing Wuxi Co.,Ltd
