Shaft torque

Using Monte Carlo simulation applied to equation 4.88, the shaft torque eapaeity is found to be ... 

Both of the torque eapaeities ealeulated, the holding torque of the hub and the shaft torque at yield, are represented by the Normal distribution, therefore we ean use the eoupling equation to determine the probability of interferenee, where ... 

Figure 4.57 Distributions and relative interference of the holding torque and shaft torque capacities for two different shaft steels...

Therefore, the Normal distribution parameters for the pump shaft torque capacity are ... 

Finally, the interference between the applied torque and the pump shaft torque capacity can be analysed to determine if separation between them is too great leading... 

Load—during the back flow the shaft torque is reduced, then restored with feed forward giving a torsional pulse with each cycle. 

Screw conveyors are suited to transport of even sticky and abrasive soiids up inciines of 20° or so. They are iimited to distances of 150 ft or so because of shaft torque strength. A 12 in. dia conveyor can handie 1000-3000 cuft/hr, at speeds ranging from 40 to 60 rpm. 

Problem understanding In many cases, experiments can provide only reliable integral values. In the case of twin screw extruders, for example, these are the shaft torque and the pressure and the temperature at the extrusion nozzle. Computational fluid dynamics, however, provide local information about pressure, velocity, and temperature within the overall computational domain. The calculation of gradients provides additional information about the shear rate or the heat transfer coefficients. 

Power density has increased significantly since the early days of extruder construction. A typical factor, and an important one for scaling up laboratory machines to production machines, is the ratio of screw shaft torque to centerline distance to the power of three. In the 1960s, a value of T/a3=5 Nm/cm3 was typical today values in excess of 13 Nm/cm3 are achieved. 

T+ dimensionless temperature in turbulent boundary layer theory (—) Tshaft shaft torque W) tb breakage time (s)... 

Load (kN) Shaft Torque (Nm) Leakage (1/min) Attitude Angle (degrees) Comment... 

The table shows cleeirly that both lo bd capacity and shaft torque reaction are affected narkedly. The reduction in both of these arises from the reduction in lubricant viscosity associated with the higher film temperatures. 

Another consideration is the shaft torque. Since impellers of the same diameter require the same power input to achieve the same blend time, an impeller with a lower power number will have to operate at a higher speed and hence will have a lower shaft torque (P = 2ttNA). Since the size of the shaft and gearbox are related to the torque, reducing the torque may reduce the agitator size and reduce the cost... 

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