Plate baffles

In the case of a packed column, the terms on the right-hand side should each be divided by the voidage, ie, the volume fraction not occupied by the soHd packing (71). In unpacked columns at low values of the sHp velocity approximates the terminal velocity of an isolated drop, but the sHp velocity decreases with holdup and may also be affected by column internals such as agitators, baffle plates, etc. The sHp velocity can generally be represented by (73) ... 

Fypass Flow Effects. There are several bypass flows, particularly on the sheUside of a heat exchanger, and these include a bypass flow between the tube bundle and the shell, bypass flow between the baffle plate and the shell, and bypass flow between the shell and the bundle outer shroud. Some high temperature nuclear heat exchangers have shrouds inside the shell to protect the shell from thermal transient effects. The effect of bypass flow is the degradation of the exchanger thermal performance. Therefore additional heat-transfer surface area must be provided to compensate for this performance degradation. 

AM(from equation 46) + AM(bypass flow) + AM(entrance/exit effects) + AM (baffle plates)... 

A counterflow plate often used for contacting gases with liquids containing sohds is the baffle plate, or shower deck (Fig. 14-21). 

The baffle plate operates with liquid dispersed and gas as the continuous phase and is used primarily in heat-transfer apphcations. 

FIG. 15-50 ((s) Typical perforated plate, (fc) Typical baffle plate. 

For the scaled-up column, suitable baffle plates are required to control axial mixing. For the final column layout the equipment vendor (Ghtsch Process Systems Inc.) should be consulted. 

The deflector device (baffle plate) must be carefully designed as described by Woods (Proc. Inst. Mech. Engrs. 180, part 3J 245-259, 1965-1966). 

Specimen Location Steel baffle plate from a test water box containing flowing cooling water... 

A test water box was installed during a 2-week trial to monitor corrosion and fouling in a utility cooling water system. A baffle plate from the test box was removed after the test. Small, hollow incipient tubercles dotted surfaces (Fig. 3.28). Small amounts of carbonate were present atop and around each tubercle. Each tubercle capped a small depression no deeper than 0.005 in. (0.013 cm) (Fig. 3.29). This indicated local average corrosion rates were as high as 130 mihy (3.3 mm/y). 

A booth should be of suffieient size to eontain any naturally oeeuii ing emissions and so minimize eseape via the open faee. An air veloeity of 0.56 m/s is required over the whole open faee a higher veloeity is needed if there is signifieant air movement within the booth or to eope with eonveetion eurrents. Booths should be deep enough to eontain eddies at the rear eorners baffle plates or multiple offtakes may be neeessary with shallow booths. 

StaufFerfett, n. Stauffer grease, cup grease. stauneA, t.i. be astonished, be surprised. Staunen, n. astonishment, surprise, wonder, staunenswert, <2. wonderful, astonishing. Staiificheibe, /. baffle plate. 

Stau-wand, /. baffle plate, -wirkung, /. damming effect, baffle effect. 

The arrangement of baffle plates and nozzles. Figure 10-96C, are important to prevent (a) tube vibration, (b) maldistribution of the process boiling fluid, and (c) poor heat transfer coefficients due to uneven and stratified flow resulting in uneven and dry spot heat transfer from nonuniform tube wetting, and others. ... 

A principle of application relative to internals is to obtain as many 180° or (second preference) 90° turns of the gas flow after it enters the drum as reasonably possible. Plat plate pieces, baffles, etc., welded to the side or nozzles are not recommended, because the vibration forces tend to fatigue and crack the welds. Baffle plates have been known to break loose on one face and ratde around in the drum. This can be potentially dangerous. The vessel itself should be designed for rugged service. 

A typical downdraft diverter used with natural-draft flues is shown in Figure 19.5. This consists of a baffle plate mounted at the top of the primary flue. There are three modes of operation ... 

Adverse conditions with up draft - the additional draft in the secondary flue causes excess air to be pulled through the diverter from the room. The baffle plate prevents the draft in the primary flue from being affected. 

The basic purpose of an oil separator is to clean the pressurized air of any oil contamination, which is highly detrimental to pneumatically controlled instrumentation. A separator consists of an inlet, a series of internal baffle plates, a wire mesh screen, a sump, and an outlet. The pressurized air enters the separator and immediately passes through the baffle plates. As the air impinges on the baffle plates it is forced into making sharp directional changes as it passes through each baffle section. As a result, the oil droplets separate from the air and collect on the baffles before dropping into the separator s sump. 

In modem boilers, both FT steam spaces and WT steam drums incorporate various devices to promote the effective separation of steam from water and the production of dry steam. These devices include horizontal separators and baffle plates in the steam/water space, and chevron driers, cyclone separators, and secondary steam scrubbers in the steam space. Older or simpler boiler designs with steam release velocities of below 3 ft/s (0.9 m/s) may rely solely on the natural separation of steam from water. 

Later HRT versions employed a fusion-welded shell rather than a riveted shell, plus baffle plates or dry pipes to improve steam dryness. They were manufactured and shipped from the factory as complete preengineered units (packaged boilers). 

The mist mixture strikes a baffle plate that separates water, steam, and other gases. Hot, gas-free water then falls to a lower storage compartment while the steam and noncondensable gases rise and are vented. 

Components include an energy source (gas, electrical), a site of energy input to solution (capillary tubes, piezoelectric plate), a means of removing large droplets (baffle plate), and tubing and a face mask to deliver aerosol. 

Internals. Commercial fluidized beds are often equipped with internals, eg., baffle plates and heat exchanger tubes. Due to their interaction with the rising bubbles they will certainly cause particle attrition. Unfortunately, no systematic investigations are available in the open literature which could serve as practical guidelines. 

To accommodate efficient heating of coarse solids, it would be desirable to break the fall of these particles during their descent by means of baffles in order to prolong their residence time, as shown schematically in Fig. 13 (Kwauk, 1979b). In this respect, a good baffle needs to cover up to 100% of the cross-sectional area traversed by vertical flow, and yet permit oblique passage as near to 100% as possible. Also, baffles should distribute solids laterally in order to give uniform solids population in the heat transfer apparatus. Thus, conceptually, an ideal baffle plate should consist of a cellular array, structurally robust, of deflectors made of infinitesimally thin sheet materials. 

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