Jiangsu Haifa Machinery Manufacturing Co., Ltd.

Long-term operation of centrifugal pumps is not "the lower the flow, the safer." When the operating point continuously deviates from the BEP (Best Efficiency Point) and enters the-flow region, impeller inlet recirculation, outlet recculation, increased radial forces, and vaporization will rapidly amplify risks of vibration, temperature rise, and wear. In engineering practice, MCSF (Minimum Continuous Stable Flow) and MCTF (Minimum Continuous Thermal) are commonly used to determine the safe lower limit: the former primarily hydraulic instability, recirculation, and vibration, while the latter prevents the liquid inside the pump from heating up or even flashing due to stagnation at low flow rates. The actual minimum continuous operating flow should generally be taken as the larger of the two values. API 610 emphasizes the reliability of process pumps in petroleum, petrochemical, and natural gas industries, and low-flow operation particularly requires attention to MCSF, POR (Preferred Operating Region), and AOR (Allowable Operating Region). Jiangsu Haifa Machinery Manufacturing Co., Ltd. (www.jslgpump.com), in the selection of API 610 OH2, BB2, BB5, VS6, high-temperature and high-pressure pumps, and multistage pumps, can integrate low-NPSHr hydraulic design, minimum flow recirculation lines, automaticirculation valves (ARC), fixed orifice bypasses, flow interlocks, and VFD wide-operating-range control to reduce damage to impellers, wear rings, bearings, and mechanical seals caused by low-flowirculation. Since 2025, automatic recirculation valves are still used to maintain the minimum safe flow of pumps when the main line flow decreases, improving continuous operation reliability. For high-pressure BB5 pumps, boiler feed pumps, CCUS injection pumps, and-flow high-head pumps, minimum flow protection should not be based solely on percentages, but should be calculated by combining pump power, medium specific heat, vaporization pressure, suction specific speed, and structural considerations. Operation below MCSF may cause cavitation, shaft deflection, and failure; operation below MCTF may result in boiling within the pump, causing more severe damage. API 610 MCSF minimum continuous flow, BB5 high-pressure pump minimum flow protection, low-flow impeller inlet recirculation, MCTF pump internal temperature rise calculation, ARC automatic recirculation valve selection, minimum flow orifice recirculation system, low-NPSHr high-pressure pump recirculation protection, BEP-POR-AOR operating region optimization, CCUS injection pump minimum continuous flow, boiler feed pump low-flow anti-vaporization. Chinese reference materials: 1. Technical materials related to API 610 centrifugal pump low-flow operation: MCSF is used to limit low-flow recirculation, vibration, and mechanical damage; MCTF is used to limit heat accumulation and flashing risk. 2. Pumps & Systems: "How to Identify & Mitigate Low-Flow Damage to Centrifugal Pumps" — low flow can cause impeller pitting, wear ring eccentric wear, vibration, shaft breakage, and overheating. 3. Pumps & Systems: "What Is an Automatic Recirculation Check Valve?", 2025 — introduces the application of automatic recirculation valves in maintaining minimum continuous flow of pumps. English literature: 1. API API Standards Plan — API 610 Centrifugalumps for Petroleum, Petro and Natural Gas Industries, current plan. 2. Pumps & Systems, Versus Thermal Minimum Continuous Flow for Centrifugal Pumps. . Pumps & Systems How to Identify & Mitigate Low-Flow Damage to Centrifugalumps. 4.umps & Systems, What Is an Automatic Recirculation Check Valve?, 2025. 5. Pumps & Systems, What You Need to Know about NH & Cavitation. 

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