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1、蠕动泵选型指导 - 提出问题，提问的含义以及 最新Verderflex 蠕动泵选型参照表,关键问题的提出,我在泵送什么液体？ 根据化学性能对照选择合适的软管和管口内塞 我如何操作这台泵？间断式运行还是持续运行？ 帮助我们了解软管的寿命或有机会选择较小的泵型 液体的温度是多少？ 了解软管的温度限制，软管寿命和泵的尺寸,关键问题的提出 II,压力和流量分别是多少？ 选择泵型，确定功率和泵旋转的速度 进口管长度和出口管长度？决定推动力和摩擦损失 液体的粘度是多少？ 确定摩擦损失 是否需要辅助真空装置? 需要什么样材质的管口联接件？通常使用卫生级的316不锈钢,但是镀钢价格更低,如何确定泵的大小?,泵
2、的流量取决于 : a) 软管内腔容量b) 泵的旋转速度c) 操作环境对泵的自吸能力有很大限制 当然同样流量下我们可选择的泵型有好几个因此我们还要考虑用户的某些因素：初期投入和长期运行成本之间的关系,一次蠕动所产生的流量,最大流量,蠕动泵选型计算表（选型软件）,计算内容 推动力和摩擦损失 脉动缓冲 Reynolds Number 进口压力 &是否需要真空 出口压力 轴功率Absorbed Power 起动扭矩Starting Torque流量：升/小时， m3h-1 or 美国加仑/分 压力 - kPa, Bar or PSI 选择3个泵型，以及每个泵型的最大转速比例和相关的软管寿命,蠕动泵选型
3、计算,- 干嘛不让电脑做工作？,静态扬程,静态扬程是液体表面到泵轴的高度 正向扬程就是“+” 自吸提升就是 “-” Ps = H * s.g. * 9.81 Ps = 静态扬程kPa H = 高度 m s.g.= 液体密度 -,液体密度对自吸扬程的影响,密度越大，静态扬程就越高，泵的最大自吸高度就越低（以上数据未考虑系统损失）,液体密度对自吸提升的影响,密度越大，静态扬程就越高，泵的最大自吸高度就越低（以上数据未考虑系统损失）,最大提升高度一览,最大提升高度一览,推动损失和脉动,推动损失是由实际管长度、流量、转速、液体比重和管内径相关La * F * n * s.g.* 0.16Pi = -
4、D2 Pi = 推动损失Impulse loss kPa La = 实际管长Actual line length m F = 流量Flow l/hr n = 转速Pump speed rpm s.g.= 比重Specific gravity D = 管内径Diameter of suction or discharge line mm,脉动是如何产生的 ?,泵推动液体向上直到出口。但是当突块脱离软管在出口点由于软管弹性复原为圆形而产生一个真空这样液体会回流到泵里面,火车可以帮助我们想象 !,减小脉动,减轻脉动的方法有 : 改变管路内径（加大直径） 通常可以解决吸入口的问题增加一段可移动的弹性软
5、管 hose should not be steel re-enforced and removes approximately 1 bar of pulsation per metre Fitting a Pulsation Damper - normal for long discharge lines where the line ID is less than the pump size typically when pumping slurries The net impulse loss is the calculated impulse loss multiplied the d
6、amper efficiency Net Impulse Loss = 90% x Calculated Impulse Loss,Pulsation Dampers,典型的脉动缓冲器 Eliminate 90% of pulsation Pressurized at 90% of discharge pressure Fit close to outlet of pump,Air Dome Sizing,Volume Air Dome = V1 x Pd,V1 l/bar VF/10 0.05 VF/15 0.2 VF/25 0.8 VF/32 1.4 VF/40 2.5 VF/50 5 V
7、F/65 9.3 VF/80 16 VF/100 33 VF125 66,V1 volume l/bar Pd Discharge pressure bar,Imperial Air Dome Sizing Guidelines,Volume Air Dome (CI) = 4.2085 X V1 x Pd,V1 l/bar VF/10 0.05 VF/15 0.2 VF/25 0.8 VF/32 1.4 VF/40 2.5 VF/50 5 VF/65 9.3 VF/80 16 VF/100 33 VF125 66,Air Dome Volume in CI V1 volume l/bar P
8、d Discharge pressure PSIAir Domes are often a low cost alternative to full spec Pulsation Dampers and suitably sized, can give good damping at moderate levels of pulsation,Reducing Pulsation,Pulsation can be reduced by : Changing the bore of line (increasing the diameter) usually best for suction li
9、ne problemsFitting a freely moving flexible hose hose should not be steel re-enforced and removes approximately 1 bar of pulsation per metre Fitting a Pulsation Damper - normal for long discharge lines where the line ID is less than the pump size typically when pumping slurries The net impulse loss
10、is the calculated impulse loss multiplied the damper efficiency Net Impulse Loss = 90% x Calculated Impulse Loss,Suction Side Impulse Loss Impact of Line ID,Example used Line Length 4m Product Viscosity 3000 CPS Product SG 0.9 Flow 3500 l/hour Pump VF50 Speed 21.8 rpm,The Effect of Undersizing the D
11、ischarge Line on Impulse Loss,Friction Loss,Friction loss for laminar flow Reynolds less then 5000 13* Le * F * C Pf = - D 4 Pf = Friction loss kPa Le = Equivalent line length m F = Flow l/hr C = Effective viscosity mPa.s or cPs D = Diameter of suction or discharge line mm again, increasing the line
12、 ID is factor that can be changed to reduce losses,Friction Loss Impact of Line ID on Suction Side,Example used Line Length 4m Product Viscosity 3000 CPS Product SG 0.9 Flow 3500 l/hour Pump VF50 Speed 21.8 rpm,Inlet Pressure,The inlet pressure is the absolute pressure at the inlet side of the pump
13、kPa.a Pinlet = Patm Pe + Ps - (Pf2 + Pi2) Pinlet = Inlet pressure kPa.a Patm= Atmospheric pressure kPa.a 85kPa at 3500m, 100 kPa at sea levelPe = Equipment pressure drops due to filters etc. kPa Ps = Static pressure kPa (could be “+” or “-”) Pf = Friction loss kPa Pi = Net impulse loss kPa i.e after
14、 allowing for the effect of any dampers,Inlet Pressure Limitations,The inlet pressure is a measure of the ability of a hose to recover to round and so refill itself with the pumped product The minimum inlet pressure is 20 kPa.a This means that the suction line should be well-engineered to minimise l
15、osses If Pinlet 50 kPa.a & the product viscosity is greater than 50% of the pumps maximum viscosity then vacuum assist is advised to help the hose recover,Maximum Pump Viscosities,VF10 4500 CPS VF15 5000 CPS VF25 6000 CPS VF32 7500 CPS VF40 9500 CPS VF50 13000 CPS VF65 17000 CPS VF80 27000 CPS VF100
16、 35000 CPS VF125 47000 CPSWhen pumping products above these viscocities then the pumps capacity will reduce,Discharge Pressure,Discharge pressure is the pressure at the outlet of pump in kPa gauge pressure (above atmospheric) Pd = Pe + Ps + (Pf2 + Pi2) Pd = Discharge pressure kPa.gauge Pe = Equipment pressure drop like filters etc. kPa Ps = Static pressure kPa (could be “+” or “-”) Pf = Friction loss kPa Pi = Net impulse loss kPa I.e after the affect of any dampers,
