武汉科技大学本科毕业设计外文文献）题 目 中高压外啮合齿轮泵设计姓 名：专 业：交通运输学 号：指导教师：外文文献一The concept of gear pump is very simple, that it is two of the most basic form of the same size gear in a close co-operation of mutual engagement with the rotating shell, the shells internal similar 8 shape, the two gears mounted inside , the diameter of gear and work closely with both sides and shell. From the extruder the material inhaled into the mouth of two intermediate gears, and full of the space, with the teeth along the shell of the rotary movement, the final two hours from the meshing teeth. Speaking in terms of gear, also known as positive displacement pump device, that is, inside the cylinder like a piston, when a tooth to another tooth space of the fluid, the liquid was squeezed mechanically to row out. Because the liquid is incompressible, so the liquid and the tooth at the same time will not be able to occupy the same space, so that the liquid has been ruled out. Because of the constant mesh gear, this phenomenon occurs on a row and, therefore, the pump provides a continuous export to exclude the amount of a turn each pump, the volume of discharge is the same. With the continuous rotation of the driveshaft, pump fluid is continuously discharged. Pump flow directly to the speed of the pump.In fact, there is little pump of the fluid loss,which makes the operation of pumps can not achieve 100% efficiency, as these fluids are used to on both sides of bearing and gear lubrication, and the pump body is also not possible with no gap, it can not be so that 100% of fluid discharged from the export, so a small amount of fluid loss is inevitable. However, a good pump can be run out of material for the majority, will still be able to achieve 93% 98% efficiency. For the viscosity or density change in the process fluid, the pump will not be affected too much. If there is a damper, for example, in the export side, one row or a limiter filter, pumps will push fluid through them. If the damper changes in their work, that is, if the filters become dirty, blocked, or limiter on the back of the hypertension, the pump will maintain a constant flow, until the device in the weakest parts of the mechanical limit (usually equipped with a torque limiter). For a pump speed, in fact, there are restrictions, which mainly depends on the process fluid, if the transmission is oil, pump can rotate at high speed, but when the fluid is a high viscosity of the polymer melt, such restrictions will be significantly reduced.Promote blood flow into the intake side of the two tooth space is very important, if not fill in this space is full, the pump will not be able to discharge the flow of accurate, so the value of PV (pressureX velocity) is also a limiting factor, and is a process variable. As a result of these restrictions, gear pump manufacturers will provide a range of products, that is, different specifications and emission (per week to the emission of volume). These pumps will fit the specific application of technology to enable the system to achieve optimal capacity and price. PEP-II pump shaft gear and a total of one species hardened usingtechnology, will be a longer working life. D-type bearing a combination of forced lubrication mechanism, so that the polymer surface by the bearing, and return to the import side of pump to ensure effective lubrication of the rotation axis. This feature reduces the degradation of polymers and the possibility of being stranded. Precision machining of the pump body can D-type gear shaft with precision bearings to ensure non-eccentric gear shaft to prevent gear wear. Structure and Parkool PTFE sealing lip sealed water-cooled sealed together. This shaft seal does not actually contact the surface, it is the principle of the sealing polymer to a semi-molten state cooling and the formation of self-sealing. Can also be used Rheoseal sealing, seal it inside the table are reverse spiral groove processing, the polymer can be imported back to the anti-pressure. In order to facilitate the installation, the manufacturer has designed the installation of a ring bolt, so that the flange and install other equipment line, which makes the manufacture of tube flange easier.PEP-II witha gear pump with the pump to match the specifications of the heating elements for the user matching, which ensures rapid heating and heat control. Heating the body and pump in different ways, the damage to these components is limited to a board, the pump has nothing to do with the whole.Gear pump by an independent motor drive, to be effectivein blocking the upper reaches of the pressure pulsation and flow fluctuations. Gear pump in the outlet of the pressure fluctuation can be controlled within 1%. In the extrusion production line using a gear pump, can increase the output flow rate of material in the extruder to reduce the shear and residence time to reduce the extrusion temperature and pressure fluctuation in order to enhance p