High-viscosity pump bearing structure

The bearings of high-viscosity pumps usually adopt sliding bearings, and spiral flow passages are specially designed on the non-load bearing surface of the bearing inner wall. The rotation of the spiral grooves is the same as that of the gear shaft. The outer end of the bearing communicates with the inlet of the pump, and the spiral groove on the inner end of the bearing communicates with the root (vacuum) of the gear tooth. When the shaft rotates, the cryogenic liquid outside the bearing is sucked into the bearing through the screw action and the pressure difference between the two ends of the bearing. After the bearing is lubricated and cooled, it flows into the tooth just disengaged from the meshing, forming a screw with sufficient lubrication and rapid heat dissipation. Self-priming low pressure lubrication system. The advantage of this lubrication method is that the lubricating fluid entering the bearing is all low-temperature medium, and the viscous lubricating fluid is easy to form a dynamic pressure oil film with strong bearing capacity. A large number of lubricating fluid cycles constantly take away the heat of the bearings, which plays a good role in the lubrication and cooling of the bearings. Because there is enough liquid to fill the roots of the gears just disengaged from the meshing, the self-priming performance of the gear pump is greatly improved and the phenomenon of air suction is avoided. This not only improves the volumetric efficiency, but also helps to reduce cavitation and reduce noise. Sichuan Machinery Research & Design Institute adopted the immersion of plain bearings in the medium and forced lubrication through special channels. This technology has been successfully applied to gear pumps in the fields of vinylon, polyester, rubber, resin, and fertilizer.
The material of the high-viscosity pump bearing is commonly used as a tool steel and is surface-hardened to improve its anti-gluing ability. If the conveying medium contains abrasive particles, a very hard bearing material such as ceramics should be used. In recent years, GS-1 PTFE composite material has been considered as an ideal sliding bearing material. It consists of cold-rolled steel sheet (base), sintered spherical porous bronze powder or copper mesh (intermediate layer), polytetrafluoroethylene (surface layer) three-layer composite material, both the advantages of metal and PTFE plastic. On the basis of this material, the Shanghai Institute of Materials Research has also developed a SF-type three-layer composite self-lubricating material with better performance. It replaces the bronze powder layer with a bronze mesh, and the surface plastic formula has been carefully selected. This bearing material is resistant to fatigue, high bearing capacity, low friction coefficient and long service life, and is a novel bearing material for improving the technical performance of gear pumps.