Circular Plates

An obvious method of increasing the filtration area in the vessel is to stack several plates on top of each other the plates are operated in parallel. One design, known as the plate filter, uses circular plates and a stack that can be removed as one assembly. This allows the stack to be replaced after the filtration period with a clean stack, and the filter can be put back into operation quickly. The filter consists of dimpled plates supporting perforated plates on which filter cloth or paper is placed. The space between the dimpled plates and the cloth is coimected to the filtrate outlet, which is either into the hoUow shaft or into the vessel, the other being used for the feed. When the feed is into the vessel, a scavenger plate may have to be fitted because the vessel will be full of unfiltered slurry at the end of the filtration period. This type of filter is available with filtration areas up to 25 m and cakes up to 50 mm thick. 

Another available design aUows discharge of the cake by vibration of the circular plates, which are slightly conical, sloping downward toward the outside of the plates. This design aUows higher pressures to be used as there are no rotating seals necessary. 

Impingement baffles are generally made of rectangular plate, although circular plates are more desirable. Rods and other devices are sometimes used to protect the tubes from impingement. In order to maintain a maximum tube count the impingement plate is often placed in a conical nozzle opening or in a dome cap above the shell. 

For a = b - d this gives the grounding resistance of the spherical anode according to Eq. (24-8) and for a = d and b 0 it gives the formula for the grounding resistance of a circular plate ground in full space ... 

The formula for the grounding resistance of a circular plate in half space [2] which can be used as an approximation for a defect in the pipe coating gives double the resistance... 

Normally the filter strueture consists of a stack of plates attached to a hollow shaft which are mounted inside a pressure vessel with eaeh plate eovered with a suitable filter medium. The slurry is fed under pressure into the vessel and the eake, which is retained by the filter medium, forms on the top of eaeh plate whilst the filtrate passes through the hollow shaft further to the proeess. Filter sizes may vary but generally the maximum is 60 m area and designed for a 6 bar operating pressure. Each circular plate in the staek is eonstructed with radial ribs that are welded to the bottom and support a horizontal eoarse mesh screen whieh is eovered with a fmer woven metal screen or filter cloth to retain the cake. The bottom of the plate slopes towards the hollow eentral shaft whieh lets the filtrate flow freely through circumferential holes and further down the shaft to the filtrate outlet. The elearanee between the plates is maintained by speeial spacers... 

Example 4.10 A circular plate with a diameter of 0.3 m is to be compression moulded from phenol formaldehyde. If the preform is cylindrical with a diameter of 50 mm and a depth of 36 mm estimate the platen force needed to produce the plate in 10 seconds. The viscosity of the phenol may be taken as 10 Ns/m. ... 

A circular plate of diameter 0.5 m is to be moulded using a sprue gate in its centre. If the melt pressure is 50 MN/m and the pressure loss coefficient is 0.6 estimate the clamping force required. 

Phj sically the redistributions may be a simple and relatively inefficient side wiper as in Figure 9-12 or 9-13 a conventional support grid or plate plus regular distribution plate as used at the top a combination unit similar to Prym support and distributor or a support plate as shown in Figures 9-14 and 9-7D and 7E, a circular plate with holes. 

A horizontal circular plate, J. 0 m in diameter, is to be maintained at 500 K by placing it 0.20 m directly beneath a horizontal electrically heated plate, also 1.0 m in diameter, maintained at 1000 K. The assembly is exposed to black surroundings at 300 K, and convection heat transfer is negligible. Estimate the electrical input to the heater and the net rate of heat transfer to the plate if the emissivity of the heater is 0.75 and the emissivity ol the plate 0.5. 

Because there is a large literature, we restrict ourselves to an interesting example, useful for understanding the axial support of thin mirrors. Consider a thin circular plate of radius a and thickness h, with elastic constant E and Poissons ratio v. Let this plate be axially loaded by gravity and assume we will support this plate against this load by N supports. This is shown in Fig. 2. 

For a uniformly loaded circular plate supported at its edges, the slope at any radius x is given by ... 

Figure 13.8. Flat circular plates (a) Clamped edges (b) Simply supported...

The colors of the cylinders represent the modern sources of energy oil (black), natural gas (yellow), wind and water (blue) and solar energy (white). Each cylinder consists of 22 movable circular plates around a central stainless steel column. At daylight, the cylinders begin to move up and down and produce energy by means of photovoltaic cells and a hydraulic system at night they rest. 

Proton conductive electrolyte properties of step 2 membranes were determined at 150°C by the impedance measurement using a 13-mm circular-plate-shaped platinum electrode. Testing results are provided in Table 1. 

A very efficient thin layer form of circular paper chromatography makes use of a circular glass disc coated with an adsorbent (silica, alumina or cellulose). The apparatus is called a Chromatotron (available from Harrison Research, USA). The disc is rotated by a motor, and the sample followed by the eluting solvent are allowed to drip onto a central position on the plate. As the plate rotates the solvent elutes the mixture, centrifugally, while separating the components in the form of circles radiating from the central point. When elution is complete the revolving circular plate is stopped and the circular bands are scraped off and extracted with a suitable solvent. 

Kirkwood s criterion may therefore be expressed for a circular plate by the proposition that if... 

Although the simple criterion of comparing the diffraction and free plate cavitation times is admittedly rough, its usefulness and approximate validity has been well established experimentally for small circular plates. And It has also been found that positions of the cavitation boundary calculated by similar methods are in good agreement with observed values, and the simple cavitation criteria thus furnish a quite reliable guide for analysis. The cavitation time is smaller for thin plates and short durations of... 

The following accurate description is given by Tomlinson —In the centre of the dial-field—Fig. 114 —is fixed a circular plate connected with a train of wheel-work, set in motion by an enclosed drum, through which the gas passes, Indicating tons of thousands, hundreds of thousands, millions, and tens of millions of cubic feet of gas. Upon this round plate is fixed a diso of paper, divided into twenty-four parts, with subdivisions, Suppose the meter to register three hundred thousand cubio feet in twenty-four... 

The jigs illustrated in an earlier ASTM standard utilised ball bushings for the load application to slide in and the electrical contact was made through a circular plate. In principle, this arrangement gives good lateral stability but... 

Rectangular or circular plates should present an area of at least 2 ft2 to the soil. Electrodes of iron and steel shall be at least 1/4 inch in thickness electrodes of nonferrous metal should have a minimum thickness of 0.06 inch. Plate electrodes are to be installed at a minimum distance of 2.5 ft below the surface of the earth. Table 5.8 gives the earth resistance values for circular plates buried 3 ft below the surface in soil with a resistivity of 10,000 Q-cm. 

Resistance of Circular Plates Buried 3 Feet Below Surface... 

Shish-kebab. In addition to spherulitic crystals, which are formed by plate- and ribbonlike structures, there are also shish-kebab crystals which are formed by circular plates and whiskers. Shish-kebab structures are generated when the melt undergoes a shear deformation during solidification. A typical example of a shish-kebab crystal is shown in Fig. 1.17. 

Calculate the diameter of circular plates that a 150-lb. man would have to wear on his feet in order to walk on water. You can assume that the plates are perfectly nonwettahle. 

A formula for the stress has been developed assuming the substrate to be a circular plate.3 It is... 

B) Tubesheets hold the tubes in place and provide the barrier between the tube-side fluid in the tube-side channels or head and the shell-side fluid. The tubesheet is a circular plate, thick enough to withstand any pressure difference between the two fluids and suitably drilled to accept the tubes. The tubesheets may be welded to the shell... 

The collecting screen inside a TSP is 14 cm in diameter and 18 cm in length. In addition, at the base, there is a circular plate of the same diameter as the screen and cooled by heat conduction. 

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