Trays plates

Example 8-12 Minimum Theoretical Trays/Plates/Stages at Total Reflux... 

In Table 8-2 Proctor [178] compares efficiencies of sieve and bubble cap trays (plates). He concludes that the sieve design provides a 15% improvement in plate efficiencies. To fully evaluate the actual efficiencies in any particular system, the physical properties, mechanical details of the trays, and flow rates must be considered. See Reference 2 also. 

The sampler unit holds a tray (plate) which can be loaded with up to 40 cups containing the individual samples. The samples are aspirated in turn with water between each one. The length of time for which the sample is aspirated determines the volume of sample that is analysed. 

APtotai Total pressure drop across sieve-tray plate, s Fraction of open area on sieve plate. 

Trays (plates) Perforated metal sheets, spaced at regular intervals within a column, on which intimate contact of vapor and liquid occurs. 

Gravity flow (usually vertical), e.g., turbo-tray, plate and moving-bed dryers, and rotary dryers (due to the slope)... 

This type of tray is designed to allow for wide variations in liquid and vapor flow. One typical design of a valve vapor opening consists of a one- to two-inch diameter orifice in the tray plate, an orifice cover, and a travel stop. At low vapor rates, the orifice cover is settled in its lower position. In this position, slots in the orifice cover allow small amounts of vapor to be distributed evenly. At higher vapor rates, the orifice cover is elevated to its upper position set by the travel stop. In this position, large amounts of vapor can flow through the valves. 

Vapor and liquid contact in openings between the angles. The angles sides rectify rising vapors so that vapors do not strike the tray plate at right angles—as is the case with sieve trays. Lower pressure drop reportedly occurs. 

Trays may be clamped (Fig. 7.2a) or bolted (Fig. 7.26) to their supports. The overlap of the tray plate on the support is usually V4 to 1 in (86). Similarly, downcomer panels are usually clamped (Fig. 7.2c) or bolted (Fig. 7.2c ) to the vertical downcomer support bars. The downcomer support bars are welded to the shell. The fastening of downcomer panels to their supports should permit some on-site adjustment for ensuring correct setting of clearances under the downcomer. 

Vertical towers for absorption, distillation, and stripping utilize trays (plates) and/or packing. Mulct et al. (1981b) present a method for estimating the purchase cost of trays installed in a vertical tower. This cost is added to Eq. (16.52) to obtain the total purchase cost. The cost for the installed trays, Cj, all with downcomers, is given by... 

Beam seats and clips allow the top flange, or top of beam, to be level with the top of the support ring. This is a very convenient feature for this type of support. In effect, it creates a level surface to support the grating or tray plates. Conversely, if the beams are supported by the support ring, then the bottom flange of the beam will sit on top of the support ring. For most applications this would be unacceptable. In order to make the... 

The compression chord can be made without a T-section, with a bolted on T-section or as a built-up T-beam. This is entirely dependent on rigidity of the vertical member. A bolted on T-section is utilized where the assembly of tray plates or grating is difficult with the T-section in place. 

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