Weir feed systems

Many different techniques have been used to either minimize or eliminate this effect. One technique involves the use of a mixing mechanism in the slip reservoir. Another feeds the slip streams through a screen mesh. (This usually only breaks the flow into much smaller streams and produces streaks that are much closer together and harder to see.) The best technique is to use a feed system that does not introduce the problem in the first place. The slip is fed to the reservoir under the surface, not on the top surface. This has been accomplished by the use of a reservoir system like that shown in Figure 4.3. This reservoir also uses a "weir feed system, in which the slip must flow from the first chamber over a retaining wall into the main feed chamber of the doctor blade assembly. The flow down the retaining wall is similar to a waterfall and provides a uniform and... 

Sedimentation Tanks These tanks are an integral part of any activated-sludge system. It is essential to separate the suspended solids from the treated liquid if a high-quality effluent is to be produced. Circular sedimentation tanks with various types of hydraulic sludge collectors have become the standard secondary sedimentation system. Square tanks have been used with common-wall construc tion for compact design with multiple tanks. Most secondary sedimentation tanks use center-feed inlets and peripheral-weir outlets. Recently, efforts have been made to employ peripheral inlets with submerged-orifice flow controllers and either center-weir outlets or peripheral-weir outlets adjacent to the peripheral-inlet channel. 

Fig. 6.6. Belt cooling system typical feeding and discharge arrangements, (a) pipe feed (b) weir-type feed (c) drop-forming feed (d) doctor blade discharge (e) breaker discharge for size control (f) discharge from return strand. (Courtesy Sandvik Conveyor, Inc.)...

The aTctual nitration reactions in a continuous process are carried out in the same type of vessels as those used for batch nitrations, with the exceptions that an overflow pipe or weir arrangement is provided for the continuous withdrawal of products and that continuous feed of all reactants is provided. Schematic diagrams of two typical nitrators for continuous operation are shown in Figs. 4-9 and 4-10. Figure 4-9 shows the kind of nitrator designed for the German Schmid-Meissner system. In this apparatus the material to be nitrated is fed into the top of the nitrator and is... 

Sedimentation vessels are typically either rectangular or circular in shape, and provide for feed of the wastewater, removal of a solids concentrate, and removal of a clarified effluent. It is also common to recycle a proportion of the solids concentrate back into the feed side of the vessel in order to help seed precipitation reactions and aid in the settling. A rectangular vessel allows for efficient use of space and facilitates an efficient inlet design that provides for even spreading of the influent. A circular vessel makes for less efficient use of space and a more complicated inlet design, but is typically designed with a conical bottom and scraper that facilitates removal of the solids concentrate from the bottom. The wastewater in a circular sedimentation basin is introduced into a center well and removed via a weir system at the periphery, such that the particle trajectory is radially outward. 

Separation system—designed to separate two liquids from each other by density differences t3npically, a solvent is introduced that will dissolve one of the components in the mixture, enhancing the separation process. A separator has a shell, weir, vapor cavity, feed inlet, extract port and pump, and raffinate port and pump. 

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