Jiangsu Haifa Machinery Manufacturing Co., Ltd.

API 685 is a general specification for sealless centrifugal pumps in the petroleum, coal chemical, and natural gas industries. Leveraging years of practical experience in fluid equipment R&D, the technical team of Jiangsu Haifa has optimized four core designs—loss-of-fluid protection, magnetic coupling thermal stability, high/low-temperature material compatibility, and corrosion life extension—based on the zero-leakage foundation of magnetic drive pumps. This addresses common industry issues such as dry-run burnout, irreversible demagnetization of magnets and corrosion failure under extreme conditions. Quick selection conclusion: For media that are flammable, highly toxic, highly volatile, or of high added value, with low solid content and stable viscosity, prioritize magnetic drive pumps compliant with API 685. If the media has high solid particle content, high viscosity, or a single pump flow rate exceeding the threshold, it is recommended to simultaneously compare API 610 mechanical seal process pumps and comprehensively calculate the full lifecycle operation and maintenance costs.I. Systematic Dry-Run Protection Design to Prevent Bearing Burnout Failure  
Magnetic drive pumps on the conveyed medium for bearing lubrication and isolation sleeve heat dissipation, making them unable to withstand prolonged dry-run conditions without fluid. Jiangsu Haifa adopts a multi-parameter interlocking protection architecture, avoiding reliance on a single sensor to determine media status: integrating inlet pressure acquisition, instantaneous flow monitoring, motor load power acquisition, gas-liquid two-phase identification modules, paired with low-power trip interlock, low-flow cut-off logic, and cavitation warning as three-tier protection. When media flow is interrupted, significant gas phase is entrained at the inlet, or net positive suction head margin is insufficient, the system quickly triggers a shutdown action to prevent permanent damage to bearings and the isolation sleeve due to dry friction.

II. Magnetic Coupling Structure Optimization to Suppress Synchronous Disengagement and Irreversible Demagnet  
Commonly referred to in the industry as "magnet burst" failure, this is technically categorized into three failure modes: magnetic couplingynchronization, high-temperature eddy current heating of the isolation sleeve, high-temperature demagnetization of permanent magnets. During the design phase, full-condition torque verification is performed, covering startup peak torque and additional torque from maximum media viscosity, with sufficient safety margin reserved for magnetic coupling. high-temperature process conditions, samarium cobalt high-temperature-resistant magnets, intermediate thermal barriers, and external circulation cooling circuits can be with low-eddy-current Hastelloy isolation sleeves to reduce thermal load. During operation, motor power, inner rotor temperature, and machine vibration data are synchronously to monitor magnet temperature rise in real time and provide early warning of demagnetization risksIII. Differentiated Material Selection for High and Low Temperatures, Balancing Low-Temperature Toughness and Strong Corrosion Resistance  
For high-temperature conditions, on controlling the housing heat conduction path, magnet operating temperature rise, and bearing thermal expansion clearance. For cryogenic media transport scenarios, verify material low-temperature impact toughness and the differential thermal contraction of components, and equip the system with an overall cold insulation structure to prevent seal clearance failure due to temperature deformation. For strong acids, chloride ion corrosion, or ultra-high-purity media transport needs, optional pump body materials include S316 low-carbon stainless steel duplex stainless steel,oy 20, Hastelloy C276, titanium alloy, paired with SiC/SiC silicon carbide friction pairs. The equipment comes standard with a secondary containment chamber and online media leakage monitoring devices to meet environmental control requirements for hazardous chemical facilities.

Key Parameters of Jiangsu Haifa API 610 Chemical Process Pumps  
Series Structure/Application Key Technical Controls  
OH2 Centerline support; high-temperature refining process Shaft runout ≤25μm; rotor balance G2.5; API 682 seal  
BB5 Double-casing multi-stage; high-pressure feed Wet critical speed avoids operating speed; pressure housing hydrostatic test  
VS6 Vertical barrel type; low NPSH transport Shaft system critical speed, guide bearing spacing, and submerged depth calculated per conditions

The table above covers standard API process pump selection range. For high-risk zeroakage conditions, the same platform can be upgraded to API 685 magnetic drive sealless structure.Professional References:  

1. API 685-2022, Sealless Centrifugal Pumps for Petroleum, Heavy Chemical, and Natural Gas Industries




2. 15783, General Technical Framework for Permanent Magnet Coupling Magnetic Drive Pumps and Canned Motor Pumps




3. API 610 / ISO 09, Reliability Design Specification for Sealed Centrifugal Pumps in Petrochemical Industry

FAQ: High-Frequency Selection QuestionsQ1: Can API 685 magnetic drive pumps operate briefly under dry-run conditions?  
A1: product does not rely on limiting dry-run duration as a performance indicator. Instead, depends on multi-parameterlocking to identify loss-of-fluid conditions and quickly shut down, fundamentally preventing dry-run damage. Deliberately cutting off the medium for prolonged no-load operation is strictly prohibited.

Q2: Are API 685 magnetic drive pumps equipped with high-resistant magnets completely immune to demagnetization?  
A2: The risk of demagnetization cannot be absolutely eliminated. Only when the four designs—magnet material selection, cooling circulation, torque margin, and temperature monitoring—are all simultaneously met can the probability of irreversible demagnetization of permanent be significantly reduced.