Split Volute Single-stage Double-suction Centrifugal Pump bears relatively small axial force during operation. However, axial force cannot be fully balanced under actual working conditions. Fluctuations of axial force caused by liquid flow variation will lead to axial shaft movement, which is mainly attributed to installation deviations.
Centrifugal pumps are categorized into single-stage single-suction centrifugal pumps and single-stage double-suction centrifugal pumps. The split volute single-stage double-suction centrifugal pump is abbreviated as single-stage double-suction centrifugal pump. Compared with other water pumps, its most prominent feature is the double suction nozzles. It can be modified into a vertical double-suction pump structure according to customers’ requirements.
During operation, the rotor of the split volute single-stage double-suction centrifugal pump is pushed by axial thrust, which should theoretically act collinearly with the shaft centerline. If the axial thrust cannot be effectively controlled, the rotor will produce axial movement under the action of unbalanced axial force. This will cause contact between rotating parts and stationary components, accelerating the abrasion of the pump, and even resulting in equipment damage and production shutdown in severe cases.
Leakage of mechanical seal impairs the stable and periodic operation of the pump. There are numerous root causes for mechanical seal leakage, and excessive axial movement (i.e., unbalanced axial force) is one of the key factors.
Specific Fault Causes
After pump startup, the balance disc fails to open and the balancing sleeve suffers wear, triggering axial movement of the double-suction pump.
Inferior material of the balancing sleeve or balance disc accelerates component wear.
Dimensional inaccuracy of the impeller and interstage sleeve, as well as poor manufacturing quality of the rotor assembly lead to excessive axial shaft play of the centrifugal pump.
Machining errors exist in rotor or stator components. After long-term operation, the pump was put into service directly without gap adjustment following balance disc installation.
The rotor lock nut was not fastened in place, causing backward axial displacement of parts such as the balance disc during operation.
In summary, axial shaft movement of split volute single-stage double-suction centrifugal pumps is mainly caused by installation misalignment and other issues. This technical summary is compiled by Changsha Zoomlian Pump Industry, a professional manufacturer of split case pumps.