When selecting, first consider the flow rate requirement. Ball valves offer low resistance and high flow rate when fully open, making them suitable for scenarios requiring rapid on/off switching, such as water supply and drainage, and HVAC systems. Should you prioritize floating or fixed ball valves? For diameters <= DN200, floating ball valves are sufficient for cost-effectiveness; for larger diameters or high-pressure conditions (>=1.6MPa), choose fixed ball valves for more stable sealing. Also, pay attention to the sealing material: nitrile rubber is suitable for normal temperature clean water, while PTFE is suitable for corrosive media. Additionally, manual or electric operation depends on the frequency of use; electric operation is suitable for frequent switching, while manual operation is sufficient for occasional use. Ductile iron itself is pressure-resistant and wear-resistant; the key is to verify that the operating pressure matches the requirements.
Gate valves are suitable for high-flow-rate applications requiring minimal flow resistance, such as main water supply pipes and industrial cooling water systems, because when fully open, the flow path is straight and has minimal impact on water flow velocity. When selecting a gate valve, focus on the sealing method. Rising stem gate valves are suitable for sewage and media containing impurities, as the valve stem does not contact the medium and is less prone to clogging. Non-rising stem gate valves are suitable for confined spaces, as they do not require space for the valve stem to rise. Note that gate valves are not suitable for frequent opening and closing, as this can easily wear down the sealing surface and lead to leakage; therefore, avoid choosing them for applications requiring frequent start-stop cycles. Regarding pressure, ductile iron gate valves are generally compatible with 1.0-2.5 MPa; simply check the pipeline's working pressure.
The biggest advantages of butterfly valves are their small size, light weight, and easy installation, making them suitable for large-diameter pipelines (DN300 and above), such as sewage treatment plants and ventilation ducts. When selecting, consider the valve plate structure. Center-line butterfly valves are suitable for low-pressure, normal-temperature (<=1.0 MPa), such as residential air conditioning systems; eccentric butterfly valves offer better sealing and are suitable for medium-high pressure (1.6-2.5 MPa) or media containing small amounts of impurities, such as industrial wastewater. The sealing material is also crucial. Soft seals (rubber) are suitable for clean water and air, while hard seals (metal) are suitable for high-temperature (>=200℃) or particulate media. Additionally, butterfly valves offer good regulating performance, making them more suitable for scenarios requiring flow regulation (such as constant pressure water supply). They can withstand frequent switching and have low maintenance costs.
Plug valves open and close very quickly, requiring only a 90-degree turn, making them suitable for scenarios requiring rapid shut-off or reversal, such as oil transportation and chemical solvent pipelines. When selecting, focus on the sealing type. Soft-seal plug valves (PTFE-lined) are suitable for corrosive media, such as acid and alkali solutions; hard seals are suitable for high-temperature, high-pressure, or particulate conditions. Note that plug valves have lower flow capacity than ball valves, so they are not a priority for high-flow scenarios. Furthermore, ductile iron plug valves are suitable for medium to low pressure (<=1.6MPa). For high-pressure applications, ensure the valve body is thickened. For small diameters, manual operation is sufficient; for large diameters or remote control, choose pneumatic/electric operation.
The main function of check valves is to prevent backflow of media. When selecting one, first consider the installation location and the direction of media flow. For horizontal pipelines (such as horizontal water supply and drainage pipes), choose a lift check valve, which has good sealing performance and is suitable for clean media such as clean water and oil. For vertical pipelines (such as the vertical outlet pipe of a water pump), choose a swing check valve, which has strong flow capacity and is not affected by the presence of small amounts of impurities in the media. Also pay attention to the nominal pressure and temperature. Ductile iron check valves generally have a temperature resistance of <=200℃ and a pressure of 1.0-2.5MPa; simply match the pipeline parameters. Additionally, when selecting a check valve for the water pump outlet, ensure the diameter matches the pump to avoid water hammer; if necessary, choose one with a buffer device.
Pressure reducing valves regulate and stabilize outlet pressure. Selection guidelines: clarify outlet pressure requirements (e.g., domestic gas for high-to-low pressure reduction, industrial steam for pressure stabilization); choose direct-acting valves for low flow/small pressure fluctuations (e.g., before household water heaters) or pilot-operated valves for high flow/large fluctuations (e.g., industrial lines) for precise control; match valves to medium and temperature (high-temperature >=300℃ for steam, room-temperature for water/oil); opt for ductile iron valves with corrosion-resistant internal components; ensure straight pipe sections are installed before and after the valve.
Safety valves protect equipment and pipelines from overpressure explosions. The key to selection is determining the set pressure, which must match the equipment's maximum allowable working pressure; it cannot be too high or too low. Then consider the opening method: spring-loaded safety valves are suitable for normal temperature and low to medium pressure (<=10MPa), such as boilers and pressure vessels; lever-type valves are suitable for high pressure and high flow rates, such as large storage tanks. Regarding the medium, steam valves with heat sinks are preferred to prevent spring failure; corrosive media require lined valves. Note that safety valves must be certified and cannot be selected arbitrarily. Ductile iron valve bodies are suitable for medium and low pressure conditions, while high pressure scenarios may require alloy materials. In addition, the discharge capacity should be considered to ensure rapid pressure relief in case of overpressure.
Shanxi Jintai Hongye Casting & Forging Machinery Co., Ltd., located in Shanxi Province, China, is a leading manufacturer of ductile iron pipe fittings, pipes, various valves, and caps, making full use of the region's abundant industrial raw materials.
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