What is the self-lubrication of melt gear pump?

The gear melt pump has a pressure building function, and there is a stable pressure difference between the feed port and the discharge port of the extruder melt pump. The self-lubricating system uses the pressure difference between the high and low pressure areas of the melt gear pump, and relies on the meshing of the gears to press the melt from the discharge port into the bearing from the inside of the bearing. Layer lubricating film, the working state of the sliding bearing should be that the lubricating film completely separates the two metal surfaces, and the lubricating film plays the role of supporting the shaft load. Then it leaks at the other end of the bearing. Using the diversion groove on the side plate, the high-pressure melt leaking from the bearing can be gathered, and then enter the feed port, so that the polymer melt participating in the lubrication is continuously renewed, thereby effectively shortening The residence time of the melt in the bearing to prevent melt decomposition due to shear thinning. The specific working principle is shown in the following figure.

When the melt gear pump is stationary, the journal is at the lowest part of the bearing, the two metal surfaces are in direct contact, and there is no melt in the gap between the shaft and the bearing. The direction is opposite to the circumferential velocity of the journal surface, causing the journal to roll to the right and offset. When the delivered melt increases and the outlet pressure gradually increases, under the action of the pressure difference between the outlet and the inlet, a part of the melt enters the bearing wedge-shaped gap from the outlet side along the bearing lubrication guide groove. The melt entering the wedge also increases gradually, the bearing area of ​​the lubricating film increases, so the frictional resistance gradually decreases, so the shaft diameter moves to the lower left. When it increases to a certain value, enough melt is brought into the journal to separate the two friction surfaces to form a bearing lubricating film. At this time, the pressure in the lubricating film can support the external load, and the balanced journal is close to the liquid lubrication state, that is, it enters a stable operation state. Therefore, when the journal enters a stable working state, the viscosity of the melt, the size of the wedge-shaped gap formed by the eccentricity of the shaft, and the rotational speed of the shaft determine the size of the generated dynamic pressure, that is, the bearing capacity of the lubricating film.

Zhengzhou Batte is an enterprise specializing in the design and production of precision chemical fiber spinning metering pumps, melt transfer pumps, melt booster pumps, and polymerization gear pumps. Products are widely used in spinning polyester, polypropylene, spandex, nylon, aramid, non-woven fabrics, acetate fibers, and the measurement of plastics, pharmaceuticals, and hot melt adhesives. info@battemachinery.com