Conical Bottoms

The simplest type of centrifugal device is the cyclone separator (Fig. 3.4), which consists of a vertical cylinder with a conical bottom. The centrifugal force is generated by the fluid motion. The mixture enters in a tangential inlet near the top, and the rotating motion so created develops centrifugal force which throws the particles radially toward the wall. 

Steep-Angle Conical Bottoms. Tanks often have a conical bottom where the slope exceeds 15—20° from the horizontal. This provides for complete drainage or even soflds removal. Because these types of tanks are more cosdy, they are limited to smaller sizes. Such tanks are often found in the chemical industry or in processing plants. 

Fig. 11. Modem fermenting tank with conical bottom CIP (cleaning-in-place) = automatic cleaning system.

Spray Drying and Agglomeration. Most instant coffee products are spray-dried. Stainless steel towers with a concurrent flow of hot ak and atomized extract droplets are utilized for this purpose. Atomization, through pressure nozzles, is controUed based on selection of the nozzles, properties of the extract, pressures used, bulk density, and capacity requkements. Low inlet ak temperatures (200—280°C) are preferred for best flavor quaHty. The spray towers must be provided with adequate dust coUection systems such as cyclones or bag filters. The dried particles are coUected from the conical bottom of the spray drier through a rotary valve and conveyed to bulk storage bins or packaging lines. Processors may screen the dry product to... 

Tanks with conical bottoms discharge cakes by gravity and those with dished bottoms have a spade that rakes and conveys the cake towards the outlet. Hence, the conical types require more headroom as compared to the dished type having the same filtration area. Conical tanks also have often an additional scavenging plate at the lower part of the cone to filter the residual slurry heel that remains below the main plates. The slurry heel that remains at the very bottom of the tank is removed through a special dip pipe to avoid discharging a wet cake. To facilitate better cake... 

Preparation. On a coml scale the nitration of naphthalene is carried out in two steps using a cylindrical jacketed reactor 1.6 x lm with a conical bottom. It is fitted with a discharge pipe 8cm in diameter and a stirrer which can be rotated at 85—90rpm. The jacket can be heated with steam or cooled with cold w. The cover is provided with an opening for the addn of naphthalene and a vent for the removal of gaseous prods... 

HTS 96-well conical plates Translucent 96-well plates with conical bottoms (Costar 3897). 

The typical back-pulse filter is a vertical tank pressure vessel with a conical bottom,... 

The batch thickener usually consists of a cylindrical tank with a slightly conical bottom. After sedimentation has proceeded for an adequate time, the thickened liquor is withdrawn from the bottom and the clear liquid is taken off through an adjustable offtake pipe from the upper part of the tank. The conditions prevailing in the batch thickener are similar to those in the ordinary laboratory sedimentation tube, and during the initial stages there will generally be a zone in which the concentration of the suspension is the same as that in the feed. 

An example of an agitated vessel in which compressed air is used is the Pachuca tank, shown in Figure 10.8. This is a cylindrical tank with a conical bottom, fitted with a central pipe connected to an air supply. Continuous circulation is obtained with the central pipe acting as an air lift. Additional air jets are provided in the conical portion of the base and are used for dislodging any material which settles out. 

The total amount of material to be digested in each tube should not cover more than half of the volume retained in the conic bottom of the tube. If the material is in excess, subdivide it in multiple 15 mL tubes. 

Houcine et al. (64) used a non-intrusive laser-induced fluorescence method to study the mechanisms of mixing in a 20 dm CSTR with removable baffles, a conical bottom, a mechanical stirrer, and two incoming liquid jet streams. Under certain conditions, they observed an interaction between the flow induced by the stirrer and the incoming jets, which led to oscillations of the jet stream with a period of several seconds and corresponding switching of the recirculation flow between several metastable macroscopic patterns. These jet feedstream oscillations or intermittencies could strongly influence the kinetics of fast reactions, such as precipitation. The authors used dimensional analysis to demonstrate that the intermittence phenomenon would be less problematic in larger CSTRs. 

J.4.1 Use of Mechanical Devices Such As Rubber Wipers. In order to reduce the amount of paint left clinging to the walls of a mix tank, rubber wipers are used to scrape the side of the tank. This operation requires manual labor and hence the percentage of waste reduction is a function of the operator. Since the benefits will be offset by increased labor, mechanization/automation should be considered. Many new mixers are available that are designed with automatic wall scrapers (Weismantel 1985). These mixers can be used with either flat or conical bottom cylindrical mix tanks. 

The nitrator sketched in Fig. 143 is a cylindrical stoneware vessel of internal diameter 1.1m and depth 0.4 m, strengthened with an iron belt. Its conical bottom is fitted with an outlet pipe. A three-way valve is provided for evacuating and filling the vessel with acid. Inside the vessel there is a perforated stoneware plate to support the cotton charge. Twenty five to twenty nine centimeters above this plate supports carry a perforated aluminium plate 15 mm thick, which acts as a false... 

Figure 6.7 Dished ends, conical bottoms and flat bottoms.

Dished ends, conical bottoms and flat bottoms of the tanks should be provided as shown in figure 6.7 above. 

To calculate the critical gas velocity needed to suspend the solid catalyst in the reactor, we recommend the correlation published by Koide et al. [28], which refers either to flat-bottom or conical-bottom columns for a bubble column without liquid motion ... 

Aliquot 1-2 x 106 cells into a 10-mL polystyrene conical bottom tube... 

E. 50 ml graduated centrifuge tubes with short conical bottoms. 

To reduce the dead volume at the electrospray tip, it was inserted (then glued) into a specially drilled flat-bottom hole, as opposed to a conical-bottom hole [132]. A similar method was used for analysis of various peptide standards and tryptic digests of lectins from Dolichlos biflorus and Pisum sativum [812]. 

In the process, chlorine is fed in below the surface of the aluminum, and the product sublimes and is collected by condensing. These air-cooled condensers are thin-walled, vertical steel cylinders with conical bottoms. Aluminum chloride crystals form on the condenser walls and are periodically removed, crushed, screened, and packaged in steel containers. 

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