中高压外啮合齿轮泵毕业设计外文文献.doc

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： 200934011 指导教师： 中高压外啮合齿轮泵-外文文献外文文献一 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 (pressure 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 using technology, 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 with a 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 effective in 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 productivity and product quality.外文文献一翻译齿轮泵的概念是很简单的，即它的最基本形式就是两个尺寸相同的齿轮在一个紧密配合的壳体内相互啮合旋转，这个壳体的内部类似“8”字形，两个齿轮装在里面，齿轮的外径及两侧与壳体紧密配合。来自于挤出机的物料在吸入口进入两个齿轮中间，并充满这一空间，随着齿的旋转沿壳体运动，最后在两齿啮合时排出。 在术语上讲，齿轮泵也叫正排量装置，即像一个缸筒内的活塞，当一个齿进入另一个齿的流体空间时，液体就被机械性地挤排出来。因为液体是不可压缩的，所以液体和齿就不能在同一时间占据同一空间，这样，液体就被排除了。由于齿的不断啮合，这一现象就连续在发生，因而也就在泵的出口提供了一个连续排除量，泵每转一转，排出的量是一样的。随着驱动轴的不间断地旋转，泵也就不间断地排出流体。泵的流量直接与泵的转速有关。 实际上，在泵内有很少量的流体损失，这使泵的运行效率不能达到100，因为这些流体被用来润滑轴承及齿轮两侧，而泵体也绝不可能无间隙配合，故不能使流体100地从出口排出，所以少量的流体损失是必然的。然而泵还是可以良好地运行，对大多数挤出物料来说，仍可以达到9398的效率。 对于粘度或密度在工艺中有变化的流体，这种泵不会受到太多影响。如果有一个阻尼器，比如在排出口侧放一个滤网或一个限制器，泵则会推动流体通过它们。如果这个阻尼器在工作中变化，亦即如果滤网变脏、堵塞了，或限制器的背压升高了，则泵仍将保持恒定的流量，直至达到装置中最弱的部件的机械极限(通常装有一个扭矩限制器)。 对于一台泵的转速，实际上是有限制的，这主要取决于工艺流体，如果传送的是油类，泵则能以很高的速度转动，但当流体是一种高粘度的聚合物熔体时，这种限制就会大幅度降低。 推动高粘流体进入吸入口一侧的两齿空间是非常重要的，如果这一空间没有填充满，则泵就不能排出准确的流量，所以PV值(压力流速)也是另外一个限制因素，而且是一个工艺变量。由于这些限制，齿轮泵制造商将提供一系列产品，即不同的规格及排量(每转一周所排出的量)。这些泵将与具体的应用工艺相配合，以使系统能力及价格达到最优。 PEPII泵的齿轮与轴共为一体，采用通体淬硬工艺，可获得更长的工作寿命。“D”型轴承结合了强制润滑机理，使聚合物经轴承表面，并返回到泵的进口侧，以确保旋转轴的有效润滑。这一特性减少了聚合物滞留并降解的可能性。精密加工的泵体可使“D”型轴承与齿轮轴精确配合，确保齿轮轴不偏心，以防齿轮磨损。Parkool密封结构与聚四氟唇型密封共同构成水冷密封。这种密封实际上并不接触轴的表面，它的密封原理是将聚合物冷却到半熔融状态而形成自密封。也可以采用Rheoseal密封，它在轴封内表上加工有反向螺旋槽，可使聚合物被反压回到进口。为便于安装，制造商设计了一个环形螺栓安装面，以使与其它设备的法兰安装相配合，这使得筒形法兰的制造更容易。 PEPII齿轮泵带有与泵的规格相匹配的加热元件，可供用户选配，这可保证快速加温和热量控制。与泵体内加热方式不同，这些元件的损坏只限于一个板子上，与整个泵无关。 齿轮泵由一个独立的电机驱动，可有效地阻断上游的压力脉动及流量波动。在齿轮泵出口处的压力脉动可以控制在1以内。在挤出生产线上采用一台齿轮泵，可以提高流量输出速度，减少物料在挤出机内的剪切及驻留时间，降低挤塑温度及压力脉动以提高生产率及产品质量。外文文献二Pumps outlineThe pump is the application very widespread general machinery, may say that is place of the fluid flow, nearly has the pump in the work. Moreover, along with sciences and technologys development, pumps application domain is expanding rapidly, according to the over-all state statistics, pumps power consumption approximately composes the national total output of electrical energy 1/5, obviously the pump is natural consumes energy the wealthy and powerful family. Therefore, raises the pump technical level to save the energy consumption to have the important meaning.First. Centrifugal pumps principle of workThe drive leads impeller revolving through the pump spindle to have the centrifugal force, under the centrifugal action of force, the liquid is flung along the leaf blade flow channel to the impeller export, the liquid sends in after the volute collection the eduction tube. The liquid obtains the energy from the impeller, causes the pressure energy and the speed can increase, and depends upon this energy the hydraulic transport to the operating location. while the liquid is flung which exports to the impeller, the impeller eye center has formed the low pressure, has had the differential pressure in the imbibition pot and between the impeller center liquid, in the imbibition pots liquid under this differential pressure function, after inhales the pipeline and pumps suction chamber unceasingly enters in the impeller.Second, centrifugal pumps structure and main spare part A centrifugal pump mainly by the pump body, the impeller, the packing ring, the rotation axis, the axis seals parts and so on box to be composed, some centrifugal pumps are also loaded with the guide pulley, the inducer, the balance disc and so on. 1. Pump body: Namely pumps shell, including suction chamber and delivery chamber. Suction chamber: Its function is enables the liquid to flow in evenly the impeller.Delivery chamber: Its function collects the liquid, and sends in it the subordinate impeller or guides the eduction tube, at the same time reduces the liquid the speed, causes the kinetic energy to further turn the pressure energy. The delivery chamber has the volute and the guide vane two forms. 2. Impeller: It is in the centrifugal pump transmits the energy for the liquid only part, the impeller with the bond fixation on the axis, leads revolving along with the axis by the prime mover, passes to through the leaf blade prime movers energy the liquid.Impeller classification: According to liquid inflow classification: Single suction impeller (in impellers one side has an entrance) and double attracts the impeller (liquid from impellers lateral symmetry liudao impeller passage). Is opposite according to the liquid in centerlines flow direction classification: Runoff type impeller, axial-flow propeller and interflow type impeller. According to impellers structural style classification: Shrouded impeller, open type impeller and semi-opened impeller.3. Axis: Is transmits the mechanical energy the important components, the prime movers torque passes to the impeller through it. The pump spindle is the pump rotors major parts, on the axis is loaded with components and so on impeller, axle sleeve, balance disc. The pump spindle depending on the both sides bearing supporting, makes the high speed rotation in the pump, thus the pump spindle in a big way wants the bearing capacity, to be wear-resisting, to be anti-corrosive. Pump spindles material selects the carbon steel or the alloy steel and after the quenching and retempering treatment generally.4. Packing ring: Is installs in the rotation impeller and the static pump housing (center-section and guide vanes assembly) between packing assembly. It is function is through controls between the two gap method, increases in the pump between the high and low pressure cavity the fluid flow resistance, reduces divulging. 5. Axle sleeve: The axle sleeve is uses for to protect the pump spindle, causes it not to corrode and the attrition. When necessity, the axle sleeve may replace. 6. Axis seals: The pump spindle and around packing box between end covers installs short for axis to seal, mainly prevents in pumps liquid divulging and the air enters in the pump, achieves seals and prevents the air admission to cause the pump cavitation goal. the axis seals form: Namely has skeletons rubber seal, the packing seal and the mechanical seal.7. axial force balancing unit.Third. Centrifugal pumps prime task parameter 1. Current capacity: Namely the pump in unit of time discharges the liquid quantity, usually indicated with the Unit of volume that mark Q, the unit has m3/h, m3/s, l/s and so on, 2. Lifting: The transportation unit weights liquid (pump suction flange) (pump discharge flange) from the pump inlet place to the pump exit, its energys increment, indicated with H, the unit is m. 3. Rotational speed: Pumps rotational speed is the pump each minute revolving number of times, expressed with N. Electrical machinery rotational speed N generally about 2900 n/min. 4. Net positive suction head: Centrifugal pumps net positive suction head is expressed that pumps performances main parameter,uses the symbolic representation. 5. Power and efficiency: Pumps power input is shaft power P, is also electric motors output. Pumps output is the active power.Fourth, pump proper energy loss Pump mechanical energy which obtains from the prime mover, has a part to transform into the liquid energy, but another part because in the pump consumes loses. In the pump all losses may divide into the following several items: 1. Hydraulic loss by the liquid in pump impact, the turbulent flow and the surface friction creates. The impact and the eddy current loss are because the liquid flow change direction produces. The liquid flows through the flow channel general meeting which contacts to present the surface friction, from this produces the energy loss is mainly decided by flow channels length, the size, the shape, the surface roughness, as well as liquid speed of flow and characteristic.2. Volumetric loss: volumetric loss was already obtained the energy liquid to have a part to flee the result which in the pump the class and leaked outward. Pumps volumetric efficiency is 0.930.98 generally. Improves the packing ring and the seal structure, may reduce the leakage, raises the volumetric efficiency. 3. Mechanical loss mechanical loss refers to the impeller lap side and the pump housing friction loss between the liquid, namely the disc loses, as well as pump spindle when packing, bearing and balancing unit and so on mechanical part movement friction loss, generally before primarily.Fifth, pumps speed change-Proportionality law 1. Centrifugal pumps speed change: A centrifugal pump, when its rotational speed change, its rated flow, lifting and the shaft power will have the change according to the certain proportion relations. At present, uses the frequency conversion velocity modulation electrical machinery to realize centrifugal pumps speed change, is a new important energy conservation way. 2. proportionality law expression In the formula, Q, H, N- pumps rated flow, lifting and shaft power The subscript 1,2 express the different rotational speed separately n- rotational speedSixth, centrifugal pumps ratio rotation Compared to the rotation is the comprehensive parameter which derives by the law of similarity, it is the operating mode function, to a pump, the different operating mode has differently compared to the rotation, for ease of carries on the comparison to the different type pumps performance and the structure, the application optimum condition (the peak efficiency spot) the ratio rotation represents this pump. When chooses the pump, may according to job requirement Q, H and unifies electrical machinerys rotational speed, calculates the ns number, determines pumps type approximately. At that time, used the positive displacement pump generally, at that time, used the centrifugal pump, the interflow pump, the axial flow pump and so on.Seventh,centrifugal pumps cavitation andinspirationcharacteristic 1.Cavitation phenomenons The pumping station transportation mediums liquid condition and the gas are can transform mutually, the transformed condition is the pressure and the temperature. Under certain temperature, the liquid starts the critical pressure which vaporizes for the vaporization pressure. The temperature is higher, the liquid vaporization pressure is higher. Pump when revolution, if its overflow part local region (for example impeller blade import later somewhere), the liquid absolute pressure drops when pulled out delivers the liquid at that time under the temperature vaporization pressure, the liquid then in this place starts to vaporize, the bubble formation (air bubble internal pressure approximately was equal to vaporization pressure). When these air bubbles along with liquid flow forward motion to high pressure region, down to around the air bubble high-pressured liquid causes the air bubble to reduce suddenly congeals. While air bubble vanishing, the liquid particle by the high speed packing hole, occurs hits mutually forms the intense pressure surge, causes the overflow part to receive the corrosion and the destruction. The above process is called the cavitation. 2. Cavitation will cause serious results: (1). has the vibration and the noise. (2). is influential to pumps operating performance: When the cavitation develops the certain extent, the steam bubble produces massively, will stop up the flow channel, will cause pumps current capacity, lifting, the efficiency and so on obviously to drop. (3). will have the destruction to flow channels material quality: Is mainly nearby the leaf blade entrance the metal weary disintegration.3. centrifugal pumps inspiration characteristic: (1). Pump has the cavitation basic condition is: Under leaf blade entrance lowest liquid flow pressure = this temperature liquid vaporization pressure .(2). effective net positive suction head: The pump entry (potential head is the entire flood peak which zero) the liquid has subtracts the value which the vaporization delivery head remains only, with expression. (3). pump essential net positive suction head: Liquid flow from pump inlet to impeller in minimal pressure point of force K place complete energy loss, with expression. (4). With and difference and relation: Pump not cavitation The pump starts the cavitation Pump serious cavitation (5). regarding a pump, to guarantee that its safe operation does not have the cavitation, must the net positive suction head also be supposed to add a security allowance regarding the pump, therefore, pumps permission net positive suction head is: 4. Enhances the centrifugal pump anti-cavitation performance the method to include: (1). I mprovement machine pump structure, reduces, is machine the pump design question. (2). Enhancement installment effective net positive suction head. Most mainly the most commonly used method uses the irrigation inspiration installment.