Direction of rotation

The optical activity of malic acid changes with dilution (8). The naturally occurring, levorotatory acid shows a most peculiar behavior in this respect a 34% solution at 20°C is optically inactive. Dilution results in increasing levo rotation, whereas more concentrated solutions show dextro rotation. The effects of dilution are explained by the postulation that an additional form, the epoxide (3), occurs in solution and that the direction of rotation of the normal (open-chain) and epoxide forms is reversed (8). Synthetic (racemic) R,.9-ma1ic acid can be resolved into the two enantiomers by crystallisation of its cinchonine salts. 

Offset halve.s. In principle, this bearing acts very similar to a pressure dam bearing. Its load-carrying capacity is good. It is restricted to one direction of rotation. 

Bearing type Load capacity Suitable direction of rotation Tolerance of changing load/speed Tolerance of misalignment Space requirement... 

Close-Clearance Stirrers For some pseiidoplastic fluid systems stagnant fluid may be found next to the -essel walls in parts remote from propeller or turbine impellers. In such cases, an anchor impeller maybe used (Fig, 18-6), The fluid flow is principally circular or helical (see Fig, 18-7) in the direction of rotation of the anchor. Whether substantial axial or radial fluid motion also occurs depends on the fluid iscosity and the design of the upper blade-supporting spokes. Anchor agitators are used particularly to obtain irnpro ed heat transfer in high-consistency fluids,... 

Direction of Rotation In circle-throw screens somewhat greater efficiency can be obtained by counterflow rotation, that is, having the material move down the screen against the rotation. Screens rotating with the flow of material will hanme greater tonnage and operate at a lower angle. 

In the second type of mill (Fig. 20-28), a cyhndrical grating is provided beneath the rotor for product discharge. Some hammer crushers are symmetrically designed so that the direction of rotation can be reversed to distribute wear evenly on the hammer and breaker plates. When such a Pennsylvania nonreversible hammermill is used for reduction, material is broken first by impacl against hammers and then by rubbing action (attrition) against screen bars. Performance data of Pennsylvania reversible hammer mills are shown in Table 20-14. 

FIG. 21-29 Table feeder. The sldrt is raised in a spiral pattern for increased capacity in the direction of rotation. Couitesy of Chemical Engineering.)... 

Since there is only one winding and the poles are already shaded at one particular end, the direction of the rotating flux is fixed and so is the direction of rotation of the rotor. The direction of rotation cannot be altered as in the earlier cases. Since there is only one winding and no need of a speed-operated centrifugal switch, these motors require almost no operational maintenance. 

The direction of rotation be established prior to this test. 

This can be checked with the help of a phase sequence indicator. This is a simple instrument that houses a small 30 motor, which rotates a pointer connected to the motor through a gearbox. The direction of rotation of the pointer will determine the phase. sequence of the system. 

An inspection for shipping damage should be made of the lube console and reservoir. Shipping blocks should be removed and, where permanent supports are used, they should be installed. The drivers should be uncoupled and connected to their respective power sources. As they are operated, uncoupled direction of rotation should be noted. When all checks out, the pumps should be aligned and connected to their drivers. 

These are made up of a large number of wide, shallow blades with a very large inlet area relative to the wheel diameter. For equal duty the speeds are lower than other centrifugal fans. They are sometimes called multivane the operating efficiencies are in the 65-75% range. They consist of a large number of relatively small blades mounted on the impeller. The blade tips are inclined toward the direction of rotation. The actual flow rate can be 2.5 times as high as the same size backward-curved fan. 

The directions of rotation at C and C have been arrived at from the following considerations. The deoxy-bases (II p. 443 Q = quinoline residue) obtained from cinchonine and cinchonidine are structurally identical, i but optically different, and since they must be optically identical at C and C, and C is no longer asymmetric, the difference between them (see table, p. 446) must be due to difference in direction of rotation at C , which must therefore be dextrorotatory in cinchonine and laevorotatory in cinchonidine, and this must also be true of quinidine and quinine respectively and of the corresponding dihydro-bases. The keto-bases, cinchoninone and quininone, might be expected to exist each in two pairs, since carbon atom 8 is, according to the formula (p. 442), asymmetric, but it is better represented by the tautomeric grouping —... 

Using the (— )-Aowocincholoipon produced as described, Rabe and Schultze, by the same sequence of reactions, have produced (—)-dihydro-quininone (m.p. 98-9[a]f, ° — 70-0° (final value EtOH)), which on hydrogenation in presence of palladium gave a mixture of bases, of which (—)-dihydroquinidine and (-j-)-dihydroquinine were isolated. The characters of these mirror-image isomerides of dihydroquinidine and dihydroquinine respectively have been given already with the directions of rotation at the centres of asymmetry C , C , C , C (see table, p. 446). 

The effect of change in the spatial relations at C and C is not clear since, as explained above, there is doubt as to the relative activities of the components of the two pairs, quinine and quinidine, and cinchonidine and cinchonine, but epf-C -quinine and epi-C -quinidine are only slightly active or, according to Dirscherl and Thron, inactive. This result supports Neeman s view that for anti-malarial activity the direction of rotation must be the same at C and C but that does not explain the... 

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