Translation:

Cast Steel Swing Type Check Valves are non-return valves that rely on the pressure of the flowing medium itself to drive the disc to swing open and closed automatically. With a cast steel body as the main structural component, they are designed for one-way flow control in industrial piping systems. These valves are widely used in industries such as petrochemical processing, power generation, and municipal services, offering the core advantages of simple structure, smooth flow, and reliable sealing.

The structural design emphasizes practicality and adaptability. The valve body is made from high-quality cast steels such as WCB and WCC, while high-pressure applications use chromium–molybdenum alloy steels such as WC6 and WC9. Manufactured through precision casting, the body wall thickness complies with ASME B16.34, providing excellent impact resistance and pressure-bearing capability. The disc features a single-plate swing design and is made from austenitic stainless steel or cast steel. The sealing surface is overlay welded with Stellite or hardfacing alloys (hardness ≥ HRC 55), delivering outstanding wear and corrosion resistance. The seat adopts either metal hard sealing or soft sealing with reinforced PTFE, forming a tight sealing interface with the disc, with leakage performance meeting ANSI B16.104 Class V requirements. The disc is connected to the body via a hinge pin, with built-in lightweight counterweights or spring-assisted return mechanisms to ensure rapid closure during reverse flow, preventing water hammer. The hinge shaft is quenched, tempered, and nitrided, and together with graphite packing, ensures leak-free operation.

Key technical parameters include nominal sizes from DN25 to DN600 (1"–24"), pressure ratings from PN10 to PN420 (Class 150 to 2500 LB), and an operating temperature range of –29 °C to 425 °C, which can be extended to –196 °C to 550 °C with special materials. Connection types include flanged ends (in accordance with ASME B16.5 and GB/T 9113) and butt-welded ends, accommodating various piping installation requirements. Manufacturing and testing strictly follow standards such as API 598, GB/T 12224, and BS 1868, including shell pressure tests, seat leakage tests, and non-destructive examinations.

In terms of performance, the valve offers three major advantages. First, it provides sensitive opening and closing response: the swinging disc experiences minimal resistance and reacts quickly to changes in line pressure, with a short operating stroke. Second, it delivers extremely low flow resistance: the straight-through flow path and large disc design result in a flow resistance coefficient of ≤ 0.5, with pressure loss far lower than that of conventional lift check valves. Third, it offers strong impact resistance: the counterweight and spring-assisted mechanisms cushion the closing action, reducing water hammer and minimizing damage to both the valve and the piping system. These valves are suitable for a wide range of media, including water, oil products, steam, and natural gas. Typical applications include pump discharge pipelines, boiler feedwater systems, oil and gas transmission lines, and municipal water supply and drainage networks, effectively preventing reverse flow that could lead to equipment damage and system failures.