Common damage modes of inlet bearings for the vertical long shaft semi submersible turbine pumps

Common damage modes of inlet bearings for the vertical long shaft semi submersible turbine pumps

　　
Let's take a look at the common ways of damage to the inlet bearings of vertical long shaft semi submersible turbine pumps. We hope this can draw everyone's attention and encourage regular maintenance and upkeep to extend the service life of the bearings.
Mechanical damage of vertical long axis semi submersible turbine pump
In severe cases, metal peeling and large areas of messy scratches may occur when in contact with the surface; In general, mechanical damage to imported bearings refers to the appearance of grooves at different levels on the alloy surface of the bearing shell. The main reason for the mechanical damage of bearings caused by the coexistence of contact surface damage and erosion is that it is difficult to form an oil film on the surface of imported bearings or the oil film is severely damaged.
Bearing cavitation of vertical long axis semi submersible turbine pump
The outer layer undergoes plastic deformation and cold work hardening. Under the repeated action of cylinder pressure impact load, the sliding inlet bearing of the vertical long axis semi submersible turbine pump loses its deformation ability locally, gradually forming wrinkles and continuously expanding. Then, as the wear debris falls off, the loaded outer layer forms cavities. When the general bearing shell undergoes pitting corrosion, pits first appear, and then these pits gradually expand and cause cracking at the interface of the alloy layer. The cracks propagate parallel to the interface until they peel off. The main cause of pitting corrosion in sliding bearings is the sudden change in the cross-section of structural elements such as oil grooves and oil holes, which leads to strong turbulence in oil flow. Bubbles are formed in the vacuum zone where oil flow is turbulent, and then due to the increase in pressure, bubbles collapse, resulting in pitting corrosion. Cavitation generally occurs in the high load area of imported bearings, such as the lower bearing shell of the crankshaft main inlet bearing.
Fatigue pitting corrosion of vertical long axis semi submersible turbine pump
Due to the overload operation of the engine, fatigue pitting corrosion of the inlet bearing of the vertical long shaft semi submersible turbine pump refers to the overheating of the bearing and excessive clearance between the inlet bearings, resulting in fatigue damage, fatigue pitting corrosion or fatigue detachment in the middle of the bearing. This type of damage is mostly caused by overloading, excessive clearance between F bearings, or unclean lubricating oil mixed with foreign objects inside. Therefore, when using, attention should be paid to preventing imported bearings from overloading and not operating at too low or too high a speed; When idling, adjust the engine to a stable state; Ensure normal clearance between imported bearings to prevent excessive or insufficient engine speed; Check and adjust the working condition of the cooling system to ensure that the engine's operating temperature is suitable.
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Corrosion of alloy on inlet bearings of vertical long shaft semi submersible turbine pump
The chemical impurities (such as acidic oxides) in the lubricating oil oxidize the bearing alloy and generate acidic substances. Corrosion of imported bearing alloys is generally caused by impure lubricating oil. Causing local detachment of the bearing alloy, resulting in irregular small cracks or pits. The main reasons for corrosion of imported bearing alloys are improper selection of lubricating oil, poor corrosion resistance of imported bearing materials, or rough engine operation and high temperature.
Vertical long shaft semi submersible turbine pump inlet bearing melting
Forming local high temperature, there are tiny protruding metal surfaces in direct contact between the journal and the friction pair of the mouth bearing. In the absence of lubrication and poor cooling, the imported bearing alloy may turn black or partially melt. This fault is often caused by the tight fit between the journal and the bearing; Lack of lubricating oil pressure can also easily cause imported bearings to burn out.