There are two reasons for damage to the seals of multi-stage pumps: human damage and natural damage. The sealing components of multi-stage pumps may be damaged by scratches, bumps, and squeezing during opening and closing. Mechanical damage between the two sealing surfaces. Under the action of high temperature and pressure, atoms undergo mutual infiltration and leakage, resulting in adhesion. When the two sealing surfaces move towards each other, the adhesive area is easily pulled apart. The higher the roughness of the sealing surface of a multi-stage pump, the easier this phenomenon is to occur.
Wear, flushing, and cavitation of the sealing surface of the multi-stage pump during media activity. The floating fine particles in the medium collide with and offend the sealing surface, causing local damage. The high-speed moving medium directly washes the sealing surface, causing local damage. When the medium mixes and vaporizes locally, gas bubbles burst and impact the surface of the sealing surface, causing local damage. The erosion of the medium, combined with the alternating action of chemical erosion, will strongly corrode the sealing surface.
Due to factors such as mutual contact between sealing surfaces, contact between sealing surfaces and the sealing body and valve body, as well as differences in medium concentration and oxygen concentration, potential differences can occur, resulting in electrochemical corrosion and erosion of the sealing surface on the anode side. However, without generating current, the medium near the sealing surface directly reacts with the sealing surface, forming chemical erosion and eroding the sealing surface.
The poor processing quality of the sealing surface mainly indicates defects such as cracks, pores, and inclusions on the sealing surface. Due to improper selection of welding and heat treatment specifications, as well as poor control during the welding and heat treatment process, the sealing surface hardness is too high or too low. The uneven hardness and corrosion resistance of the sealing surface caused by incorrect material selection or improper heat treatment are mainly caused by blowing the underlying metal onto it during the welding process, which dilutes the alloy composition of the sealing surface.