Product Knowledge | Basic Information on JW-LOK Double‑Card Ferrule Fittings

Release date:

2026-04-27

With regard to ferrule fittings, JW-LOK has its own standards and manufacturing processes. We do not recommend mixing or interchanging JW-LOK ferrule fittings with components from other manufacturers to avoid potential issues related to performance, leakage, cost, and safety. For more information on our products and services, please contact us.

A double‑ferrule fitting is a fastener used for pipe connections, primarily in applications such as hydraulic and pneumatic systems that require high‑pressure sealing. By means of the clamping action of two ferrules, it securely holds the pipe within the fitting, ensuring both leak‑tightness and pressure resistance at the joint. Due to their simple structure, ease of installation, and excellent sealing performance, double‑card sleeve fittings are widely used in the petroleum, chemical, and machinery manufacturing industries.

Structure and Operating Principle

The core design of JW-LOK’s twin‑ferrule fittings lies in separating the sealing function from the clamping function, with four key components working in concert:

Component composition:

• Mainly composed of It consists of four components: the body, the front ferrule, the rear ferrule, and the nut.

Sealing mechanism :

• When tightening the nut, the nut pushes the rear ferrule forward, which in turn drives the front ferrule.

• Before the internal conical surface of the fitting is pressed against the ferrule, it eliminates pipe tolerances and forms… First seal.

Urgent mechanism :

• As the resistance increases, the rear ferrule moves inward, forming on the tube. The second support is tightly secured to provide vibration resistance and pull-out strength.

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Action process :

• During the nut’s rotational advancement, the front ferrule eliminates the tolerance between the inner diameter and the tube’s outer diameter, while the rear end lifts to form a seal with the body’s inclined surface.

• The rear ferrule, in turn, exerts radial compression, securely clamping the tube. 。

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JW-LOK Product Specifications

JW-LOK Jingwei Valve Industry offers a comprehensive range of ferrule fittings, covering materials, dimensions, shapes, and end‑connection types, to meet the diverse and complex requirements of customers across various industries and application scenarios.

01. Product Features of Ferrule Fittings

• Available in a variety of materials and formats;

• The components are machined to high precision, ensuring accurate deformation of the ferrule and tubing.

• Hardened and polished threads extend the joint’s service life and prevent galling between male and female threads.

• The nut’s threads are silver-plated, which effectively reduces the coefficient of friction with the body’s threads.

• The elbow channel features an arcuate connection to ensure smooth fluid flow.

• Each joint is marked with its dimensions, material, and furnace number.

• Easy to disconnect and re-tighten the connector. 。

02. Fitting Product Specifications

Material Type	Typical example
Stainless steel	Standard 316, 316L, 304, 321, etc.
Alloy	20, 400, 600, 625, 718, 825, C-276, Duplex Steel 2205, Super Duplex 2507, etc.
Other metals	Carbon steel, brass, Aluminum, Titanium, etc.
···	···

• Size: Imperial system 1/16" – 2", metric 2–50 mm.

• Shape: Straight-through, elbow (45°/90°), tees, crosses, pipe caps, plugs, and so on.

• Termination: Thread (NPT, ISO, SAE/MS, etc.), flanges, welding, and more.

Regarding ferrule fittings, JW-LOK has its own standards and manufacturing processes. It is not recommended to mix or interchange JW-LOK ferrule fittings with components from other manufacturers, as this may lead to performance issues, leaks, increased costs, and safety concerns. For more information on our products and services, please contact us.