Rake Height

The use of slowly rotating rakes is beneficial in large thickeners to direct the underflow to the central outlet at the bottom of the tank. At the same time the slow motion of the rakes tends to give a gentle agitation to the sediment which facilitates its consolidation and water removal. The height requirement of the rakes must be added to that needed for the thickening zone to achieve the desired underflow concentration. 

Fig. 3.47. Mechanically wipped-ofF rakes. 1 — rakes, 2 — wipping equipment, 3 — separator of scraped material, 4 — gears, 5 — control room, 6 — sensors for measuring the level height, 7 — reservoir for scraped material... 

Hashimura M, Hassamontr J, Domfeld DA (1999) Effect of IN-plane exit angle and rake angles on burr height and thickness in face milling operation. J Manuf Sci Eng 121(1) 13-19... 

The weir is designed to minimize turbulence. A mechanical rake or rotating Archimedean screw removes the coarse sohds. Water drains away as the sohds are removed. The speed of the rake or rotating shaft is critical to the efficiency of separation. The height of the weir must be adjustable to change the depth of the pool, the rising velocity, and the cut point between coarse and fine. 

Temperature instrumentation is outlined in Figure 7.3, where each number corresponds to the location of a specific diode. SDl-3 were the same from LOX tests. The sixth design modification involved adding the maximum number of diodes allowable with two electrical feedthroughs on the RD lid. SD4-17 were located along a vertical rake spaced 1.27 cm (0.5 in.) apart, and these diodes measured both temperature and height of the... 

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