PTFE Envelope Gaskets

PTFE Envelope Gaskets

PTFE Envelope Gaskets are composite sealing elements designed to combine the chemical resistance of PTFE with the mechanical resilience of a soft inner core. These gaskets are engineered for glassware systems, metal flanges, and chemical process pipelines, where aggressive media, temperature variation, and reliable sealing are critical.

The PTFE envelope completely encapsulates the filler material, ensuring that only PTFE contacts the process fluid, while the core provides compressibility and recovery, overcoming the limitations of solid PTFE gaskets.

Construction & Design Principle

• A PTFE Envelope Gasket consists of:
• Outer Envelope: Seamless PTFE jacket forming the chemical barrier
• Inner Core (Filler): Soft, compressible material such as EPDM, Viton®, Neoprene, or Non-Asbestos Fiber

This construction delivers excellent sealing performance at low bolt loads, making it especially suitable for glass and fragile flange systems.

Material Properties & Chemical Resistance

• Process Contact Material: 100% PTFE
• Chemical Resistance:
• Strong acids & alkalis
• Chlorinated & fluorinated compounds
• Organic solvents
• Corrosive and high-purity chemicals

The inner core is fully isolated from the process, ensuring zero chemical attack on the filler.

Key Technical Features

• PTFE Encapsulation
  Guarantees chemical inertness and prevents media permeation
• Soft Inner Core
  Provides elastic recovery, improved compression, and reduced cold flow
• Low Bolt Load Requirement
  Ideal for glass flanges, enamelled equipment, and fragile connections
• Vacuum & Pressure Capability
  Suitable for full vacuum and moderate pressure applications
• Wide Temperature Range
  Performance governed by PTFE envelope and selected core material
• Leak-Tight Sealing
  Excellent surface conformity compensates for minor flange imperfections

Installation Advantages

• Easy alignment on flange face
• Reduced risk of flange damage
• Uniform compression across sealing surface
• Improved service life compared to solid PTFE gaskets
• Minimal maintenance requirement

Typical Applications

• Glass Pipeline & Glass Reactor Flanges
• PTFE Bellow Connections
• Glass-to-Metal Interfaces
• Chemical Process Piping
• Pharmaceutical & Fine Chemical Plants
• Vacuum Systems & Distillation Units
• Corrosion-Prone Process Lines

Industries Served

• Chemical & Specialty Chemical Processing
• Pharmaceutical Manufacturing
• Research Laboratories & Pilot Plants
• Glass Process Equipment Manufacturers
• Industrial Process Plants

Technical Specifications (Typical)

• Envelope Material: PTFE
• Core Options: EPDM / Viton® / Neoprene / NA Fiber
• Size Range: DN standards as per flange requirement
• Pressure Range: Vacuum to moderate pressure (system dependent)
• Temperature Range: Based on PTFE & core material combination
• Flange Standards: Table E, Table F, ASA 150 (on request)

Customization Options

• Custom DN sizes & thickness
• Selection of core material based on application
• Special flange patterns or profiles
• Suitable for glass, metal, and lined flanges

Why Choose PTFE Envelope Gaskets?

• Superior chemical resistance
• Better sealing than solid PTFE
• Lower bolt stress on glass flanges
• Longer operational life
• Reduced leakage risk
• Cost-effective for corrosive environments

Comparison Advantage

Feature	Solid PTFE Gasket	PTFE Envelope Gasket
Chemical Resistance	Excellent	Excellent
Compressibility	Low	High
Bolt Load Requirement	High	Low
Suitability for Glass	Limited	Excellent
Sealing Reliability	Moderate	High