In the operation and maintenance of industrial fluid equipment,most personnel focus on core components such as rotors and seals,yet easily neglect transmission components like couplings.Couplings can compensate for installation deviations within a certain range and buffer impact from working conditions,and their failure usually indicates deeper hidden operational hazards in the system.

-Bonve Pumps Cam-type Double Rotary Pump-

The vast majority of couplings are designed for a service life based on rated torque and allowable deviation.However,factors including insufficient on-site installation accuracy,equipment foundation settlement,residual pipeline stress,medium thermal displacement and operation&maintenance oversights will continuously exert additional stress on the shaft system.Coupled with process fluctuations and impacts from variable frequency drives,couplings are prone to exceeding the design allowable range and eventually fail.Such failures are rarely caused by quality issues of a single part,but mostly arise from system-level operation deviations.

Angular misalignment is a highly concealed cause of failure.When an included angle exists between the drive shaft axis and the pump shaft axis,the bending stress of a diaphragm coupling will concentrate on the outer diaphragm and bolt holes,gradually initiating fatigue cracks.Typical manifestation during operation is that axial vibration intensifies at multiple frequencies,with a vibration phase difference of nearly 180°between the two sides.For prevention and control of such faults,high-precision alignment technology is the core prerequisite.During operation,radial deviation and face runout shall be measured simultaneously,the impact of thermal expansion shall be taken into account,and each alignment shall be accompanied by soft foot inspection of base feet and pipeline stress assessment,so as to control the actual angular deviation within 10%of the maximum allowable value.

Axial misalignment stems from installation spacing deviation.When the flange spacing of the coupling exceeds the design range,the components will remain in a stretched or compressed state for a long time,further increasing the operating load of the bearings at both ends.Typical symptoms include motor current fluctuation,abnormal temperature rise of thrust bearings and axial pulsed vibration.Prevention requires strict verification of installation spacing against drawings,completion of motor magnetic center check and thermal expansion calculation,and implementation of pre-tension installation in accordance with design requirements,with axial deviation controlled within 10%of the maximum allowable value.

Torque overload features sudden occurrence.Scenarios such as process parameter fluctuation,pipeline slug flow,electrical faults and emergency shutdown may generate torque peaks exceeding the bearing limit,instantly causing diaphragm buckling and flange deformation.Countermeasures shall focus on proactive prevention and control.After suspected overload,immediately inspect for cracks,calculate the safety factor under actual working conditions,install shear-type safety elements in high-risk scenarios,and continuously analyze operation logs and current curves to locate the root cause of the fault.Torsional vibration is mostly excited by variable frequency harmonics and frequent motor start-stop.It is necessary to adjust the stiffness and inertia of the coupling to keep the critical speed away from the daily operation range.

At the application site of pipeline-conveying rotary pumps,the stringent alignment requirements of rigid couplings were hard to meet on site,leading to excessive shaft system stress and even pump shaft fracture.After replacement with flexible elastomer spacer couplings,their multi-directional deviation compensation capability reduces alignment difficulty,and the alignment-free replacement design also greatly cuts down downtime for operation and maintenance.

To achieve effective coupling fault prevention,the core is to establish a system-level operation and maintenance philosophy.Alignment operations shall cover the whole process of soft foot inspection,base level verification and pipeline stress assessment,standardize bolt tightening procedures,and match the safety factor according to working conditions.Through multi-parameter condition monitoring covering vibration,temperature and current to realize early warning,passive rush repair is transformed into proactive maintenance,which can effectively prolong equipment service life and reduce the risk of unplanned shutdown.

Bonve pump always adheres to the philosophy of "Wholeheartedly Making Good Rotor Pumps," committed to providing global customers with customized conveying and mixing solutions. If you have technical inquiries, selection needs, case references, or other cooperation intentions related to Bonve rotor pumps, please feel free to contact us.  

Service Hotline: 0574-87588986 13586591794  

Official Website: www.bvpumps.com  

Business Email: market@bonvepumps.com  

We look forward to working with you to drive efficiency and innovation in industrial fluid transmission with precision technology.