Custom Engineered Sealing Solutions by Beldam Crossley
Made in Britain
Precision-made PTFE envelope gaskets from Beldam Crossley offer outstanding chemical resistance and superior sealing reliability in aggressive industrial environments. Manufactured in the UK using decades of engineering expertise, our envelope gaskets are designed for performance in pipeline systems, distillation columns, reactor vessels, and more.
Also known as jacketed gaskets, PTFE-sheathed gaskets, or encapsulated gaskets, envelope gaskets are composite sealing components that combine a chemically inert PTFE outer layer with a compressible internal insert. This hybrid design delivers both the chemical compatibility of PTFE and the resilience needed to compensate for flange irregularities—especially useful in large diameter or corroded pipework.
Sizes: Up to DN600 (ASA 24″).
Sizes: Up to DN600 (ASA 24″).
Sizes: Any size over 450mm (18”) ID.
Custom envelope configurations, including reversed envelopes and full-face gaskets, are available on request.
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Each gasket insert can be tailored to meet your performance requirements with a variety of core materials, including:
Operating temperature range: from -240°C to +250°C, depending on insert material.
Envelope gaskets are ideally suited for use in:
These gaskets provide long-term sealing integrity even under fluctuating temperature and pressure conditions, making them a trusted solution for demanding industrial processes.
With a heritage spanning over 149 years, Beldam Crossley has earned a global reputation for manufacturing precision-engineered sealing components with unmatched reliability.
Certified Quality & Compliance
We hold the following internationally recognised accreditations:
These standards reflect our commitment to delivering sealing solutions that meet the strictest quality and environmental requirements.
We don’t believe in one-size-fits-all. Beldam Crossley offers complete customisation, blending PTFE with performance-enhancing fillers such as glass, graphite, or stainless steel, tailored for your pressure, temperature, and chemical exposure needs.
All envelope gaskets are engineered and manufactured at our UK facility, enabling responsive support, fast lead times, and consistent product quality.
Beyond Envelope Gaskets: Complete Sealing Solutions
Beldam Crossley offers a full range of high-performance PTFE-based sealing components, including:
We also specialise in developing bespoke polymer blends for enhanced mechanical, thermal, or chemical resistance.
Whether you need a standard flange gasket or a fully custom sealing solution, our engineers are here to help.
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Envelope gaskets use less PTFE while delivering the same chemical protection. The insert improves resilience and lowers cost.
Yes. Beldam Crossley specialises in custom sealing solutions. We can design and produce gaskets to suit non-standard flanges or complex geometries.
Yes, PTFE is non-reactive and FDA-compliant, making our gaskets ideal for sanitary applications.
We have been innovators in our industry for over a century. Since 1876 we have a solid track record of providing industrial sealing & bearing technology that protects lives, investments and environments.
