Standard coupling housings (including housings for fittings, mechanical tees and crosses, and valve bodies) are cast from ductile iron to ASTM A536, and Grade 65-45-12 (equal to QT450-12) standards. Ductile iron is chosen due to its special combination of better physical characteristics over other materials, and the relative ease of manufacturing to various demanding standards. The Grade 65-45-12 refers to the 65,000 psi/450MPa minimum tensile strength, 45,000 psi/312 MPa minimum yield, and 12% elongation.
Housings are normally two identical castings for couplings through 24"/600mm sizes. From 26"/650mm on up, coupling housings are cast in multiple identical segments to guarantee the concentricity and ease of handling.
All products are supplied with a high performance paint, unless other requirements are specific upon ordering. The standard paint material is an epoxy resin, with a thickness average of 8-25um, die painted, and heat dried to provide an excellent adhesion and outstanding anti-corrosion performance.
The unique, C-shaped pressure responsive gasket design has been the grooved system since its original launch onto the market. Relying on a compound resiliency and initially flared design, the gasket seals on the A dimension of the pipe O.D. The design accommodates the pipe movement, while sealing under both pressure and vacuum characteristics. Gaskets are carefully molded in patterns conforming as closely as possible to the inside containment area of the housing. This allows separate components to be put together to form an integral coupling unit with a combination of efficient sealing. One size gasket is suitable for all styles of couplings in the same size, and will not affect pressure rate changes.
Bolts and Nuts
The standard bolt head is an oval-neck configuration that conforms to the openings in the housing's bolt pads. The track head nuts and bolts conform to ASTM A183 (GB3098, GB150) minimum tensile, and 120,000psi/800mpa. Plated (to ASTM B633/GB5267) nuts and bolts are standard on most couplings.
LEDE company design and manufacture grooved piping system jointing fittings, is a leading China grooved pipe couplings manufacturer and supplier, provide pipe jointing and flow control products of fire protection system and water work system. There are different sizes of pipe couplings for grooved piping system, made in accordance with UL, CE, ISO certificates, etc. Engineered with complete automation equipment and manufacturing expertise, LEDE company provides quality ductile iron grooved couplings as well as custom firefighting and water supply solutions based on the client needs.