Double Sleeve Tube Fittings
Origin
• When it appeared: Mid-20th century, developed by Swagelok in the 1940s–1950s.
• Background:
At that time, piping systems in petrochemical, military, and aerospace industries mostly used welding or threaded connections. These methods were prone to leakage under high pressure, high temperature, and vibration conditions, and were difficult to install and maintain.
• Innovation:
The double ferrule fitting uses a front ferrule for sealing + back ferrule for gripping design, allowing a strong metal-to-metal seal without welding. It can be repeatedly assembled and disassembled without losing sealing performance.
• Core principle:
• Front Ferrule: Bites into the tube surface to create a metal seal.
• Back Ferrule: Grips the tube to prevent pullout.
Applications
Due to its high sealing capability, vibration resistance, and reusability, double ferrule fittings are widely used in:
• Oil and gas: pipelines, offshore platforms
• Petrochemical and chemical industries: corrosive fluid transfer
• Instrumentation: pressure gauges, analyzers, laboratory systems
• Military and aerospace: high-pressure hydraulic and fuel systems
• Shipbuilding and power plants: hydraulic controls, fuel transfer
• New energy: hydrogen and natural gas storage and transport
Standards
There is no single unified ISO standard exclusively for double ferrule fittings. However, commonly referenced standards include:
• ISO 8434-1: Metallic tube fittings for fluid power and general use
• DIN 2353: German standard covering fitting design, dimensions, and pressure ratings
• SAE J514: American standard for hydraulic tube fittings
• Leading brands like Swagelok, Parker, and Hylok follow proprietary technical standards, but these are generally compatible with ISO/DIN standards in size and sealing performance.
Summary sentence:
Double ferrule fittings provide reliable, reusable metal-to-metal sealing in high-pressure and vibration environments, widely used in petrochemical, military, aerospace, and other demanding fields, conforming to international standards like ISO 8434 and DIN 2353.
Hainar can provide you with double card sleeve connectors. Please feel free to inquire if you need them
Post time: Aug-13-2025