Compression tube fittings, essential components in various industrial and mechanical systems, are available in a wide range of brands, each with distinct designs, sizes, and performance characteristics. It’s crucial to understand the benefits and limitations of different fitting designs when selecting the appropriate tube fitting for a specific application.
There are primarily two types of tube fittings: single ferrule and double ferrule. The purpose of ferrules in tube fittings is multifaceted, primarily focusing on creating a secure seal and effectively gripping the tubing. Single ferrule fittings rely on one ferrule to both seal and grip the tubing. In contrast, double ferrule fittings distribute these functions across two separate ferrules. The front ferrule in a double ferrule fitting is designed to form a tight seal between the ferrule, tubing, and the body of the fitting, while the rear ferrule is responsible for gripping the tubing and maintaining the front ferrule’s position. This design is particularly effective in preventing the tubing from being ejected or ‘blown out’ under high-pressure conditions.
What’s Single Ferrule Tube Fittings?
A single-ferrule compression fitting consists of a single ferrule, a nut and a body fitting that simultaneously grips the tubing and forms a leak-proof seal between the compression nut and the body of the fitting. This single ferrule serves the dual purpose of sealing and securing the fitting in place.
Typically, single-ferrules are designed asymmetrically. In such fittings, as the nut is tightened, it transfers torque to the ferrule, potentially leading to uneven compression of the ferrule over time. This asymmetrical compression can result in issues such as leakage or difficulty in disassembling the components.
Single-ferrule fittings are often preferred in scenarios where reducing the number of components is beneficial without sacrificing the integrity of the seal. Consequently, single-ferrule designs are most effective when crafted from softer materials like plastic and brass. The ferrule’s angled front end is engineered to compress into the fitting body, ensuring a firm grip on the tubing.
In general, single-ferrule designs are particularly advantageous for use in compression fitting applications that are subject to significant vibration or pulsation.
Applications of SS Single Ferrule Tube Fittings
- Water Plumbing Systems: Used in residential and commercial buildings for water supply lines due to their robustness and leak-proof qualities.
- Pneumatic Applications: Ideal for air compression systems, pneumatic control systems, and other applications requiring tight seals in dynamic systems.
- Instrumentation Systems: Used in measurement and control instrumentation where precision and reliability are crucial.
- Hydraulic Systems: Applied in systems where hydraulic fluids are transported under high pressure.
- Chemical Processing: Used in chemical plants for handling various chemicals, especially where corrosion resistance is essential.
- Food and Beverage Industry: Employed in processing lines for food and beverages due to their non-toxic and corrosion-resistant nature.
What’s Double Ferrule Tube Fittings?
A dual-ferrule compression fitting is made up of four components, a front ferrule, a back ferrule, a nut and a body fitting.
In compression fitting designs that use a dual-ferrule, the two functions provided by the single-ferrule are distributed among the front and back ferrules. One ferrule seals the fitting while the other one holds it in place.
Double-ferrule designs are typically used in compression fittings that are manufactured using rigid materials such as stainless steel. The symmetrical nature of the dual-ferrule ensures that tightening the nut does not cause asymmetrical compression of the ferrule itself.
Double ferrules come with a front ferrule that compresses into the fitting body and a smaller, freely rotating back ferrule that can easily decouple the nut from the front ferrule. The chemically hardened front edge of the back ferrule can bite down and grip the softer metal of the tubing. This prevents an uneven transfer of torque and protects the system from leakages.
Generally speaking, dual-ferrule designs are better suited for compression fittings that are made for high-pressure applications.
Applications of SS Double Ferrule Tube Fittings
- High-Pressure Applications: Preferred in systems where extra security against leaks is needed under high pressure, such as in oil and gas industries.
- Gas Applications: Used in gas transmission lines, especially for flammable and hazardous gases, providing extra safety.
- Semiconductor Manufacturing: In cleanrooms and semiconductor manufacturing, where leak integrity and purity of materials are critical.
- Laboratory Equipment: Utilized in analytical instrumentation and laboratory equipment for precise and leak-free connections.
- Aerospace and Defense: In aerospace and defense industries for applications that demand high reliability and strength under extreme conditions.
- Power Generation: Employed in power plants, especially in systems dealing with steam, high temperatures, and pressures.
Conclusion
When working with instrumentation tube fittings for any piping-based application, an appropriate and reliable seal between the various components is necessary to avoid leakages and subsequent damage.
Depending on the nature and purpose of the compression tube fitting application, either single-ferrule or dual-ferrule can be used. Making the correct choice will ensure that your piping system does not become subject to leakages or damage.
Hydraxio is a leading manufacturer and supplier of stainless steel single and twin-ferrule compression fittings. If you are wholesalers, distributors, and brand manufacturers of hydraulic hose fittings and adapters. please Contact Us!
