(Bonve Pump Industry Cam Rotary Lobe Pump)

The pump body and drive motor are like the"main characters,"but if the two"key supporting roles"—the shaft seal and coupling—are improperly selected,the entire unit will still suffer frequent failures,and may even cause safety incidents.

The shaft seal is used to prevent the internal medium from leaking outward along the shaft.Packing seals have a simple structure and low cost,but they allow a certain amount of drip leakage and have high friction power loss.They are generally used for water and non-hazardous media,not recommended for chemical media,and strictly prohibited for toxic,flammable,or explosive media.Mechanical seals achieve sealing through a pair of precisely fitted rotating and stationary ring faces,with extremely minimal leakage and long service life.They are the absolute mainstream in the petroleum and chemical industries.They can adapt to high pressure,high temperature,high corrosion,and media containing particles(requiring hard-on-hard materials like silicon carbide).For slurries containing a large amount of solid particles,such as mining tailings or phosphate slurry,dynamic seals(back vanes or auxiliary impeller seals)are an economical and reliable choice.Their principle is to use centrifugal force generated by rotation to reduce the pressure at the shaft seal,resulting in almost no leakage during operation.However,it is important to note that they require the pump's inlet pressure(Ps)to be less than 10%of the outlet pressure(Pd),and during shutdown,they rely on an auxiliary shutdown sealing device(often a packing seal)to function,which typically has a short service life.

The coupling connects the pump shaft and the motor shaft.Its core functions are to transmit torque,compensate for misalignment between the two shafts,and absorb vibration and shock.Pumps commonly use flexible couplings.Elastic pin couplings(e.g.,GB/T 5014)have a simple structure,require no lubrication,have low alignment requirements,and are widely used for centrifugal pump units with smaller power(e.g.,<50 kW).Metal disc pack couplings(diaphragm couplings)have greater load capacity,higher reliability,require no lubrication,and are resistant to high temperatures.They have become the preferred choice for medium and high-power pump units(especially when complying with API standards).Their manufacturing often follows API 671 or ISO 14691 standards.

When selecting a coupling,the required calculated torque(Tc)must be determined:Tc=9550 Pa K 1/n(Nm).In the formula,(Pa)is the pump shaft power(kW),(n)is the rotational speed(r/min),and K is the service factor.This factor is crucial as it accounts for starting impact,load fluctuations,etc.According to recommendations from standards like API:generally,take 1.2-1.5 for centrifugal pumps;it can reach 2.5 for metering pumps;for rotary pumps,take 1.75-2.5 depending on the number of cylinders.The coupling's nominal torque[Tn]must be greater than Tc,and its allowable speed[n]must be higher than the pump's operating speed and the motor trip speed.Furthermore,the coupling's bore size must match the shaft diameters of the pump and motor.

In explosive hazard areas,the protective cover outside the coupling must be made of spark-resistant materials,such as aluminum or copper alloys.Neglecting these details means even the best pump could lead to a complete shutdown due to a small seal failure or coupling fracture.

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  

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