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Swagelok medium-pressure tube fittings (FK series)

Swagelok FK series medium-pressure fittings have improved fluid connections in tough applications like oil and gas exploration, R&D systems, and the hydrogen market. They offer reliable, leak-tight connections for advanced systems in fluid handling and gas sealing applications.

FK Fitting Brochure

Download Swagelok FK fitting documentation

Learn more and get the Digital Catalog, an Installation Instruction, the Installer's Pocket Guide and other information

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The reliability of a Swagelok FK fitting

Swagelok FK series medium-pressure fittings install up to five times faster than cone and thread fittings, reducing installation time, assembly, and maintenance costs. The fittings are vibration-resistant and offer a leak-tight gas seal for applications up to 20 000 psig (1378 bar). Ideal for use in challenging environments where secure, high-pressure connections are critical.

These medium pressure fittings are reliable and efficient, offering robust performance in severe applications while protecting workers and the environment. They meet EC-79 standards for hydrogen applications up to 700 bar (10 150 psig) and feature a preassembled cartridge for easy, accurate installation. The simple two-piece design, with color-coded ferrules, ensures proper orientation and installation using standard tools. The strain-hardened 316 stainless steel body provides a lightweight, space-saving solution. FK series fittings are also available in NACE MR0175/ISO 15156 compliant versions.

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Anatomy of a hydrogen fitting
Gas seal
Reliable gas seal
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Gas seal

The unique feature of the double ferrules, also known as twin ferrules, in a Swagelok tube fitting ensures that a larger portion of the rear ferrule is in contact with the tube. This results in improved grip on the material, which is important for direct axial support and sealing.

Vibration resistance
vibration-resistance
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Vibration resistance

The double ferrule design creates a double mechanical grip on the tubing, significantly reducing the likelihood of fittings loosening during vibration. In fact, it is estimated that in a typical topside installation, approximately 20% of the cone and thread connections require rework during initial assembly and pressure testing. FK Series fittings require almost no rework due to the simplicity of installation.

5x faster assembly
5x-faster-installation
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5x faster assembly

FK series fittings are installed by screwing a pre-assembled cartridge (which consists of a nut, two ferrules and a plastic arbor) onto the fitting body. The tubing is then inserted and marked to determine alignment, and with one 360-degree turn, the connection is complete. After checking with an inspection gauge that the fitting is correctly assembled, you are assured of an optimal connection.

Certificates

Many certifications demonstrate that our tubular fittings meet or exceed industry specifications.
Certificates

Expertise

Inquire about application options specific to your system. Swagelok tubular fittings are used worldwide and experts are available everywhere.

Expertise

Warranty

All products and assemblies are supplied according to the Swagelok warranty.
Warranty

Installation

Installation of Swagelok tube fittings is easy. In three steps, using standard tools, you will have proper installation. This leads to uniformity in assembly and application of the fittings.
Installation

Material

Swagelok stainless steel contains at least 17% chromium and 12% nickel, which is above ASTM specifications.
Material

Reliability

Using Swagelok tube fittings gives you reliability and security through three aspects: tubegrip, sealing and vibration resistance.
Reliability

Reuse

Correctly installed Swagelok tube fittings provide a leak-tight connection even after multiple disassemblies and reassemblies.
Reuse

Safety

Swagelok tube fittings offer optimum safety and reliability in industrial applications.
Safety

Training

Become an expert yourself! Swagelok offers several training courses on tubular fittings installation and inspection.
Training

Medium pressure fittings

FK 316 stainless steel fittings are available in straight, elbow and T shapes to meet configuration needs in a lightweight, space-saving design.

UNION

Unions

Combine tubing easily with an elbow, tee, or straight union, available in 316 stainless steel for medium-pressure tube fittings.

maleconnectornpt

Male connectors

Construct a leak-free connection in process instrumentation and industrial applications with a male connector for medium-pressure tube fittings.

femaleconnectornpt

Female connectors

Create a secure connection with female connectors for tube fittings, designed to receive and hold male connectors.

bulkheadunion

Bulkheads

Make reliable fluid transfers with a bulkhead designed specifically for passing a tubing connection through a panel or steel partition.

CAP

Caps and plugs

Pressurize the fluid system by capping medium-pressure connections or plugging ports.

SS-4FK-NFSET

Parts and accessories

Nut and ferrule sets and medium-pressure gap inspection gauges for tube fittings.

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Material Selection Brochure

Material selection guide

Learn about the different types of corrosion, materials most commonly affected and what materials are used in various solutions. Visit the page or receive the guide by email.

Material Selection Guide Send by Email

Videos

FK fitting installation training

1-day training on the operation, assembly and use of Swagelok FK fittings.

Photography-MPHP FK Series-12
Hidden Costs of Leakage

Download "hidden costs of leaks."

Learn more in a chapter from the Tube fitter's manual. It provides insight into using the leak formula with practical examples. Aimed at preventing leaks and unnecessary costs.

Advice on gas and liquid systems

Requesting a survey, also called evaluation and consulting, by a Swagelok Netherlands engineer is always an option. We listen to your challenges, ask about your priorities and systems.

If necessary, we perform on-site inspections at your site and provide comprehensive recommendations. This will improve the reliability of your system, while also lowering your operational costs and reducing risks.

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