| 1 | Swing Check Valve | A hinged disc opens with forward flow and closes when reverse flow develops. | Water supply, wastewater, oil and gas, petrochemical processing, and general industry. | Carbon steel, stainless steel, ductile iron, cast iron, and alloy steel. | Flanged, wafer, threaded, and butt-weld ends. | Low pressure loss, simple construction, and suitability for large pipe sizes. | May be unsuitable for severe pulsation or applications requiring very fast closure; installation orientation is important. | API 6D, API 598, ASME B16.34, EN 12334, and GB/T 12236 where applicable. | Widely used in large municipal, energy, water-treatment, and process-equipment projects. |
| 2 | Wafer Check Valve | A compact disc or plate assembly is installed between pipe flanges and closes against reverse flow. | HVAC, water treatment, fire-protection systems, chemical plants, and utility piping. | Ductile iron, carbon steel, stainless steel, and aluminum bronze. | Wafer, lug, or double-flanged designs. | Short face-to-face dimension, low weight, and reduced installation space. | Requires correct flange alignment and adequate flow velocity; valve suitability depends on pipe orientation. | API 594, API 598, ASME B16.34, and applicable GB/T requirements. | Supports compact skid packages and cost-sensitive infrastructure projects with limited installation space. |
| 3 | Dual-Plate Check Valve | Two spring-loaded plates open independently and close rapidly when flow reverses. | Power generation, pump discharge lines, cooling-water systems, petrochemical plants, and pipelines. | Carbon steel, stainless steel, duplex stainless steel, and nickel alloys. | Wafer, lug, and flanged connections. | Compact design, low weight, and reduced water-hammer risk compared with some conventional swing designs. | Spring performance, disc wear, minimum flow velocity, and installation direction must be evaluated. | API 594, API 598, ASME B16.34, and MSS SP-125 where specified. | Frequently selected for high-throughput industrial systems where space, weight, and dynamic response are important. |
| 4 | Lift Check Valve | A piston or poppet lifts from its seat under forward flow and returns to the seat under reverse flow. | Steam, high-pressure process lines, boiler systems, and refinery piping. | Carbon steel, forged steel, stainless steel, and alloy steel. | Flanged, threaded, and socket-weld connections. | Good sealing capability and suitability for high-pressure service. | Needs a suitable flow direction and generally performs best in horizontal piping or approved vertical arrangements. | API 602, API 598, ASME B16.34, and EN 12334 where applicable. | Relevant to compact high-pressure equipment packages and thermal-power applications manufactured in China. |
| 5 | Piston Check Valve | A guided piston moves axially to control forward flow and block reverse flow. | Steam, condensate, refinery services, high-pressure water, and process systems. | Forged carbon steel, stainless steel, chrome-moly alloy steel, and nickel alloys. | Flanged, butt-weld, socket-weld, and threaded ends. | Stable guided movement and reliable shutoff under appropriate operating conditions. | Pressure drop can be higher than that of some swing designs; lubrication, trim, and orientation may affect service life. | API 602, API 598, ASME B16.34, and applicable pressure-equipment specifications. | Matches the requirements of high-pressure process equipment and domestic energy-sector supply chains. |
| 6 | Ball Check Valve | A ball moves away from the seat during forward flow and returns to the seat to prevent reverse flow. | Slurry handling, wastewater, sewage, pumps, low-pressure water systems, and abrasive services. | Cast iron, ductile iron, carbon steel, stainless steel, and rubber-lined materials. | Flanged, threaded, socket, and grooved connections. | Simple operation, resistance to clogging in selected designs, and suitability for dirty fluids. | Ball and seat materials must match the fluid, solids content, temperature, and pressure requirements. | EN 12334, API 598, and applicable Chinese valve and pressure-testing standards. | Important for municipal wastewater, mining, environmental-protection, and pump-system projects. |
| 7 | Diaphragm Check Valve | A flexible diaphragm deforms to permit forward flow and returns to a sealing position against reverse flow. | Corrosive chemicals, ultrapure water, pharmaceutical production, food processing, and dosing systems. | PTFE-lined steel, polypropylene, PVC, PVDF, stainless steel, and elastomer-lined bodies. | Flanged, threaded, solvent-weld, and sanitary clamp connections. | Good isolation from moving metal components and compatibility with selected corrosive or hygienic services. | Diaphragm chemical compatibility, temperature limits, fatigue life, and cleaning requirements are critical. | EN 12334 where applicable, sanitary piping standards, and manufacturer-specific material specifications. | Supports China’s growing chemical, pharmaceutical, semiconductor, and water-purification industries. |
| 8 | Nozzle Check Valve | An axial nozzle and spring-assisted disc provide controlled opening and rapid closure. | Power plants, compressor discharge lines, LNG facilities, gas pipelines, and high-velocity systems. | Carbon steel, stainless steel, duplex stainless steel, and alloy steel. | Flanged, wafer, and butt-weld connections. | Fast response, reduced reverse-flow travel, and good suitability for pulsating or high-velocity service. | Flow coefficient, spring selection, pressure drop, noise, vibration, and dynamic stability require engineering review. | API 6D, API 594, API 598, ASME B16.34, and project-specific pipeline specifications. | Increasingly relevant to gas, LNG, hydrogen-ready infrastructure, and modern power-generation projects. |
| 9 | Tilting-Disc Check Valve | A disc pivots around an offset hinge and tilts out of the flow path during forward operation. | Large-diameter water pipelines, cooling-water systems, hydropower, and industrial circulation systems. | Ductile iron, carbon steel, stainless steel, and bronze alloys. | Flanged and double-flanged connections. | Suitable for large diameters and designed to reduce disc travel and closing impact. | Hinge design, closing characteristics, flow velocity, and water-hammer analysis should be reviewed. | EN 12334, API 594 where applicable, API 598, and relevant Chinese standards. | Fits large-scale water-transfer, hydropower, desalination, and municipal infrastructure programs. |
| 10 | Sanitary Check Valve | A hygienic poppet, spring, ball, or diaphragm mechanism prevents reverse flow while minimizing contamination risk. | Food and beverage, dairy, biotechnology, pharmaceutical, and clean-process systems. | 316L stainless steel, 304 stainless steel, PTFE, EPDM, FKM, and other approved elastomers. | Tri-clamp, weld, threaded, and hygienic flange connections. | Cleanable surfaces, hygienic construction, and compatibility with validated process systems. | Surface finish, dead-leg control, elastomer certification, CIP/SIP requirements, and drainability are essential. | ASME BPE, 3-A Sanitary Standards where required, EHEDG guidance, and applicable food or pharmaceutical regulations. | Supports China’s expanding pharmaceutical, biotechnology, dairy, beverage, and high-purity manufacturing sectors. |