Slotted pipes

Fig. 1.35 (a) Osborne s rotating slot slurry sampler, (b) Osborne s sampling tank, (c) Cross s slotted pipe slurry sampler... 

Osborne [25] described a sampler that consists of a narrow slot continuously rotated on an axis parallel to the slun7 flow (Figure 1.35a). Cross [26] used a slotted pipe mounted vertically in the overflow compartment next to the vortex finder of a hydrocyclone (Figure 1.35c). 

DRY PIPE - A perforated or slotted pipe or box inside the drum and connected to the steam outlet. 

Curtain coating. Curtain coating (95 to 100% TE), which is similar to flow coating, is used to coat flat products on conveyorized lines. The coating falls from a slotted pipe or flows over a weir in a steady stream or curtain while the product is conveyed through it. Excess material is collected and recycled through the system. Film thickness is controlled by coating composition, flow rates, and line speed. 

Uniform distribution of gas entering the bed is very important to prevent gas channeling and desiccant damage. Neither the wet feed gas nor the regeneration gas should impinge directly on the bed. A perforated basket or screen-wrapped slotted pipe, with the feed gas exiting radially at a low velocity, provides better feed gas distribution than a perforated plate above the bed (Ballard, 1978). 

Well screens are sleeve-like units fitted over the ends of intake pipes in water or oil wells. They well illustrate the nomenclature problem outlined at the start of this chapter in that they are relatively small and clearly act entirely by straining, yet they have always been called screens, and so are described here. In construction they may vary from simple slotted pipes, with or without a surrounding screen, to quite specialized designs of sleeves, as shown in Figure 3.11. They consist essentially of a cylindrical tube, sealed at one end, with porous material of some kind in that part of the walls that sit over perforations in the sides of the end of the suction pipe, over which the screen is fastened. They serve to prevent entry of particles of rock from the drill site into the water or oil being extracted. 

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