Vertical surface collectors

Vertical surface collectors can readily provide information on relative drift (e.g., the amount of drift from one field trial compared to another). However, it is difficult to obtain absolute data unless the precise collection characteristics are known for the droplet size spectrum at the point of spray collection, wind speed and air turbulence intensity. " The SDTF conducted studies in wind tunnels to compare the collection efficiency of different types of drift collector used in its field studies. These studies showed that collection efficiency on strings was several orders of magnitude higher for 0.8-mm diameter cotton string than for 2-mm diameter polyethylene line and vertical o -cellulose strips or squares. The higher collection efficiency for the cotton... 

Vertical surfaces collect spray primarily by impaction. Plants and other entities with a vertical component will collect some material by impaction, and typically also by deposition, as discussed in the previous section. While horizontal collectors will tend to collect all or most material that falls out on to them, vertical collectors will have collection efficiencies that are more closely related to their physical characteristics, especially collector diameter. The SDTF used a-cellulose cards oriented perpendicular to the ground and strings made of cotton or Teflon in its field studies to assess spray volumes at locations above the ground. Many other researchers have used strings for assessing airborne spray volumes in drift studies. ... 

Other paper collectors that have been used to assess droplet size and distribution patterns include cards such as Kromekote. This was one of several types of collector that provided information on spray deposition in the held, a-Cellulose samplers are fibrous in nature, and include a vertical component to their aspect. This type of collector, along with Mylar cards and other types of card samplers, are often used to provide information on spray coverage as amount of material per unit surface area. 

Ideated to 300-400 °C, ferrosilicon is periodically loaded into furnace 6, which is a steel vertical two-coned shaft apparatus with a water jacket. The cooling surface of the furnace is 7 m2. The diameter of the wider section of the furnace is 900 mm, the diameter of the narrower section of the furnace is 480 mm. The total height of the furnace is 3300 mm. The lower cone has a smaller height (650 mm) and is lined with diabase tile in one layer. Chlorination is conducted with evaporated chlorine, which is fed into the lower section of the furnace through the distribution collector at a speed of 70-100 m3/h. 

The distilled toluene vapours enter water cooler 17, a steel enameled vertical heat exchanger of the vessel in a vessel type with the heat exchange surface of 4 m2. There toluene condenses and is collected in collector 18, from where it self-flows into settling box 19. The settled toluene is sent to regeneration and re-used in manufacture. 

In vertical skimmers the oil droplets must rise upward countercurrent to the downward flow of the water. Some vertical skimmers have inlet spreaders and outlet collectors to help even the distribution of the flow, as shown in Figure 3.7. The oil, water, and any flash gases are introduced below the oil-water interface. Small amounts of gas liberated from the water help to "float" the oil droplets. In the quiet zone between the spreader and the water collector, some coalescence can occur, and the buoyancy of the oil droplets causes them to rise counter to the water flow. Oil will be collected and skimmed off the surface. 

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