Torque level

Rake drive controls protec t the drive mechanism from damage and usually incorporate an alarm to indicate high torque with an interlock to shut down the drive at a higher torque level. They can have an automated rake raising and lowering feature with a device to indicate the elevation of the rakes. 

From Table 1 in Appendix I, the probability of failure P = 0.135666. This suggests that when the holding torque level is reaehed in serviee, due to a malfunetion stopping the hub from rotating, there is about a 1 in 7 ehanee that the shaft will yield before the hub slips. Clearly this is not adequate if we want to proteet the shaft and its transmission from damage. 

Cure characteristics are shown in Figure 14.15 the antireversion agent has no effect on scorch resistance and time to optimum cure. The beneficial effect becomes apparent when reversion occurs, as observed in the control compound. The compound containing the antireversion agent on the other hand maintains a torque level close to the maximum. 

Some important conditions concerning the estimation of error should be pointed out. First, modulus measurements of rectangular bars are made in torsion and the calculations contain assumptions that may depend on geometry. How this influences error, particularly at low torque levels is not known. Second, the strains were kept constant at 0.1% other strains might not yield the same results. On the other hand one would expect an inverse proportionality to exist between the magnitudes of error and strain. Thirdly, these errors were estimated for a frequency of 1Hz. 

The melt is stirred with an agitator running at 30 rpm to keep the catalyst in suspension. The torque on the agitator is monitored to determine the level of inorganic impurities and carbon residues that have accumulated. At a preset torque level the polymer melt is completely pyrolyzed and the carbon residues and impurities are then evacuated from the chamber using an auger positioned in the base of the vessel. Char removal is only activated when the vessel is cooled. 

Notice that Polymer 4 was still growing at the end of its measurements, as was Polymer 5 at the same reaction time. This indicates that the potential for continued polymerization via the NCO-OH reactidn still remained. The torque level achieved in polymerizations 4 and 5 was less than that of 1 and 2, reflecting the higher polymerization temperature of 4 and 5. 

At six minutes the polymer flux had essentially regained the selected mastication temperature, 200°C, but notice that during this interval mastication reduced torque precipitously to the low level of 320 meter-grams. After a total mastication time of 10 minutes the polymer melt torque level fell a bit further to 250 meter-grams and declined little more during the full 20 minute term of the experiment. 

One endurance-related measure uses either the number of repetitions that can be performed at 20, 25, or 50% of maximum peak torque or force. The units used to reflect endurance in this case are number of repetitions at a specified torque or force level. One difficulty with this definition has been described previously, that is, the issue of relative vs. absolute muscle endurance. Rothstein and Rose [1982] demonstrated that elderly subjects with selected muscle fiber type atrophy were able to maintain 50% of their peak torque longer than young subjects. However, if a high force level is required to perform the task, then the younger subject would have more endurance in that particular activity [Rothstein, 1982]. Another difficulty is that the repetition method can be used only for dynamic activities. If isometric activities are involved, then the time an activity can be sustained at a specified force or torque level is measured. Why have different units of endurance Time could be used in both cases. Furthermore, the issue of absolute vs. relative muscle endurance becomes irrelevant if the demands of the task are measured. 

The high degree of fill combined with the low rotational screw speed of the machine lead to high torque levels. Thus, these processes are usually performed on a ZSK MEGAcompounder (Me). In comparison, when producing granulated catalyst carriers a ZSK MEGAvolume (Mv) is suitable more often. A typical machine set up is shown in Fig. 19. 

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