A ferrule-type tube fitting (also called compression fitting or ferrule coupling) is a detachable rigid-pipe connector composed of a fitting body, ferrule(s) (single or double), and nut, suitable for sealing connections of non-corrosive or corrosive media such as oil, water, and gas. Its core structure uses a 24° cone-seal design—tightening the nut drives the ferrule's cutting edge to bite into the pipe outer wall, forming a mechanical bite seal without welding. It is reusable, reliable, high-pressure capable (working pressure range 10–63 MPa), and vibration-resistant. By ferrule count it is divided into single-ferrule and double-ferrule types; by shape it includes straight, elbow, tee, cross, stud, and weld variants.
Sealing mechanism (double-ferrule example): tighten the nut → ferrule is pushed into the body's internal cone → the front ferrule's sharp edge radially contracts and cuts into the pipe wall, forming the first annular seal → the ferrule outer cone seats tightly against the body's 24° cone, forming the second seal → the back ferrule grips the pipe tail, providing anti-pullout and anti-vibration capacity. After correct installation, a raised ring forms on the pipe—the telltale sign of proper ferrule bite.
Standards: China's current GB/T 3733-2008 through GB/T 3747-2008 series covers straight stud, taper-threaded straight, tee, cross, and weld-type ferrules, technically aligned with ISO 8434-1; the series applies to piping systems with pipe outer diameters of 4–42 mm and maximum working pressures of 10–63 MPa. Common pressure classes are divided into LL (extra-light), L (light), and S (heavy) series.
Supply-chain clues show that the number 13021772 is labeled "Weichai-Deutz ferrule straight tube fitting" across multiple auto-parts/heavy-truck channels, with the applicable model/brand field reading "Weichai-Deutz" and at least one supplier listing it as a "226B Class-B spare". The Weichai-Deutz 226B is a diesel platform produced by Weichai using licensed German Deutz technology, widely used in wheel loaders, road rollers, and motor graders—meaning 13021772 may circulate in the supply system as a generic connector for the Weichai-Deutz 226B platform. However, the correspondence between 860131603 and this number, and between this part and specific XCMG hosts, cannot be confirmed from public sources and require verification through XCMG's parts system or catalog numbering.
