Tapered rotor

The rotors may be one of several zero-clearance designs, a rigid fixed clearance type, or in the case of tapered rotors, an adjustable clearance construction type (Fig. 16). One vertical design includes an optional residence time control ring at the end of the thermal surface to hold back product and thus build up the film thickness. The majority of thin-film evaporators in operation are the vertical design with a cylindrical fixed-clearance rotor shown in Fig. 14. 

These studies were continued by Min [46] who compared rotors with R/L and R/R screws with Banbury double-flighted rotors and tapered rotors. She found that R/L screw rotors combinations both pumped rubber in the same direction. No inter-rotor material transfer was observed. R/R rotors, Banbury double-flighted rotors, and tapered rotors circulated the rubber around the mixing chamber. 

A variety of conical refiners were developed that involved modifications of the Jordan refiner. The Hydrafiner, for example, has a short, low taper, high speed rotor, and wide bars (10). The stock is driven through the refiner by an impeller which is fitted to the smaU inlet end of the rotor shaft. The Claflin refiner has a very short, high taper plug. Vanes that fit on the wide end of the plug draw the stock through the unit (11). 

The rotor is squirrel cage with short-circuited copper rings at the ends. Here also, to vary the starting characteristics of the motor, the skin effect is used by providing deep bars, flat bars, tapered bars or other types of slots (discussed in Section 2.3). 

Veloeity triangles at the mean seetion of the blading are to be submitted by the Seller. The blading shall be designed to minimize blade erosion eaused by tlie partieulate entrained in the flue gas witli tapered and twisted rotor and stator airfoils. The blade design used shall have at least tliree years of sueeess-ful operating time in FCC serviee for tlie frame proposed. 

The rotor blades shall be of the tapered/twisted, free vortex, reaetion design (Figure 5-21). The blades shall be speeifieally designed for the dirty FCC flue gas applieation. Seller shall provide a Goodman Diagram for the highest stressed loeation... 

Figure 5-19. Rotor assembly showing tapered shaft end.

Particulate material is forced to the outside of the tapered segment and collected in a drop-leg located at the dust outlet. Most cyclones have a rotor-lock valve affixed to the bottom of the drop-leg. This is a motor-driven valve that collects the particulate material and discharges it into a disposal container. 

All compression mixes have an optimum compressing speed. This is why tablet press manufacturers install variable speed controls for the rotor or turret and the powder feeding mechanism. Many compression mixes are speed sensitive and will not produce satisfactory tablets at inappropriate speeds. The dwell time, where maximum pressure is applied to the mix, is relative to the peripheral speed of the turret and the diameter of the punch head flat. Any air in the compression mix must be expelled to avoid laminating or splitting of the tablet. If air is compressed within the tablet, when the pressure applied by the punch is released, the compressed air expands and breaks the tablet. Precompression or dies with a taper in the bore will... 

Shaft Dla. Rotor Dla Coupling n Shaflt Tapered/Cyllndrlcal ... 

For proper operation of a centrifuge, only those tubes recommended by their manufacturer should be used. The material used for the tube must withstand the RCF to which the tube is likely to be subjected. Polypropylene tubes are generally capable of withstanding RCFs of up to 5000 Xg. The tubes should have a tapered bottom, particularly if a supernatant is to be removed, and should be of a size to fit securely into the rack to be centrifuged. The top of the tube should not protrude so far above the bucket that the swing into a horizontal position is impeded by the rotor. 

To evaluate the effects of blade geometry and configuration, Kim [1] performed a number of microrotorcraft spin tests on a single-rotor device using a load cell to measure thrust and a laser to measure rotor speed. The motor was driven using an external power supply. Kim tested blades with varying aspect ratios, cambers (the asymmetry of an airfoil s top and bottom shape), and thicknesses, tapers, pitches, and configurations. 

A variety of basic or standard thin-film evaporator designs is commercially available today. They are either vertical or horizontal, and can have cylindrical or tapered thermal bodies and rotors (Figures 11-24,11-25). 

Figure 2.2 Decanter centrifuge (from Alfa-Laval, 1978). 1, Hollow drive shaft with stationary inlet tube 2, erosion protected solids discharge ports 3, tapered beach section of rotor for discharge of solids 4, solids deposited on rotor wall 5, screw conveyor 6, pond of clarified liquid 7, exchangeable overflow weirs 8, conveyer drive shaft from gearbox.

Reactions heated in a microwave oven do not necessarily require special apparatus. For example, they can be conducted in vessels that range from simple laboratory glassware such as an Erlenmeyer flask covered with a watchglass to flasks of various shapes that are fitted with standard-taper glass joints (Fig. 2.32a). Specially designed pressure vessels can also be used. A number of tubes can also be mounted on a rotor so that multiple reactions can be conducted simultaneously (Fig. 2.32b). 

---