Slot tank

The structures for separation of substances by sedimentation — gravel and sand traps, sedimentation and slot tanks — are simple to construct and undemanding in their operation. 

Cross-draft velocity was normalized by dividing the measured cross-draft ve-locit by the capture velocity calculated at the tatik centerline. Capture velocity at the tank centerline was calculated using Silverman s - centerline velocity (Eq. (JO.l)) for unflanged slot hoods. There was considerable scatter in the data, show ing chat cross-draft velocity alone is not responsible for low capture efficiency. 

Rim exhausts are a specific application of slot hoods, which in turn are a type of exterior or capture hood. Rim exhausts are slot hoods placed along the rim or edge of an area source such as an open surface tank or vessel opening. Open surface tanks are widely used in indu.strial settings for cleaning, stripping. 

Rim exhausts are suitable for area sources of contaminant. They are limited in the area over which they can draw with adequate velocity. In practice, the slot hood should be within 0.6 m of the far edge of the source. For an open surface tank this means that a slot hood on one long side is necessary for tanks up to 0.6 m in width hoods on both long sides are necessary for tanks up to 1.2 m in width and rim exhaust is not practical for tanks wider than 1.2 m. For those situations, push-pull ventilation or enclosure type hoods are recommended.- ... 

Rim exhausts are slot hoods located on or around the edge of a source such as an open surface tank. Flanges may be added to decrease the airflow from behind the slot (uncontaminated air) and therefore increase the airflow from in front of the slot (contaminated air). The plenum downstream of the slot, if located above the slot, may act as a flange. Flanges may also be added to the sides of the source (tank) away from the slot hood. These flanges also act to increase the flow of contaminated air into the tank. Tank flanges, however, may interfere with process activities by limiting access to the tank. 

The outlet piping downstream of the exit slots should be connected to a water leg located outside the tank. Since the height of the water leg is adjustable, it can he used in regulate the liquid level. This will maintain a relatively constant level in the vessel and help to keep the oil/watcr interface above the upper spreader. This interface must be kept above the upper spreader for efficient separation. An oil skimmer should he tied in to the lank... 

While gas liquid separation should occur primarily in the gas boot, smaller gas bubbles will be liberated as the flowstream velocity slows farther downstream The gas released by this secondary separation should be routed into the vapor space of the tank This is accomplished bv providing vent holes at the top of the central nser and by placing a vent in each spreader. The vent for the upper spreader should end just below the top of the tank. The vent for the lower spreader should end above the top of the upper slots, just below the upper spreader. The cross-sectional area of each vent should he large enough to keep vapor velocities low This will prevent the vapor from lifting water as it moves up the vent. 

Sagger. NATO code-name for a Russ anti-tank missile, also known by the US alphanumeric designation AT-3, which is currently extensively deployed in Europe and elsewhere. In its man-portable version, the missile is carried into action in a Fiberglas case in which the warhead is separated from the motor. The lid of the case forms a base for launching the missile which has a launch rail on the underside of the motor section. The two parts are taken out of the case and the front legs of the rail on the motor section are slotted into the lid so that there is a small angle of elevation. This is done to ensure that the missile enters the operator s field of view when launched. The warhead (HEAT, piezo-electric fuze) is then clipped to the body. 

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

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