Plate construction

The mechanical design features of sieve plates are described in this section. The same general construction is also used for bubble-cap and valve plates. Details of the various 

Two basically different types of plate construction are used. Large-diameter plates are normally constructed in sections, supported on beams. Small plates are installed in the column as a stack of pre-assembled plates. 

Diagrams and photographs, of sectional plates, are given in Volume 2, Chapter 11. 

The stacked type of construction is used where the column diameter is too small for a man to enter to assemble the plates, say less than 1.2 m (4 ft). Each plate is fabricated 

The plates are not fixed to the vessel wall, as they are with sectional plates, so there is no positive liquid seal at the edge of the plate, and a small amount of leakage will occur. In some designs the plate edges are turned up round the circumference to make better contact at the wall. This can make it difficult to remove the plates for cleaning and maintenance, without damage. 

---

A beam from an actual sample will require a more elaborate slit S3rstem for collimation if the sample is broad. The Soller slit (Figure 4-7), a stack of thin parallel plates, is such a system. The reasoning that supports this construction is as follows. Were the sample a point or a line source, a slit between sample and crystal or a slit between crystal and detector would be enough for satisfactory collimation. With a two-dimensional sample, both slits would be needed to get this done. But this arrangement is wasteful of emitted intensity because the detector sees the sample as a line source. To use all the sample area effectively, a system of parallel slits is needed. To eliminate the divergent rays in such a system, the slits must be extended in the direction of the beam, and this leads to the parallel-plate construction in the Seller slit system. 

A combination of gasketed and welded plate construction is also used. An aggressive process fluid flowing between welded plates and a benign process stream, or service stream, between gasketed plates. 

The infinite parallel plates construct may sound theoretical and impractical, but it is not. The flow in screw extruder channels, between the rotor and the wall of an internal mixer or between the rolls of calenders and roll-mills, to mention a few, can be considered to first approximation as taking place locally between parallel plates in relative motion. 

Carbon-zinc cells are distinguished by the composition of the electrolyte. The Leclanche cell has an aqueous ammonium chloride-zinc chloride electrolyte. The higher performance zinc chloride cell mainly has zinc chloride electrolyte and may contain a small amount of ammonium chloride. Cells are available in cylindrical and flat plate constructions, as well as combinations of cells for higher voltage applications. Approximately 30 billion carbon-zinc cells are manufactured annually. 

The baffle-plates may be arranged in 90 two groups, whereof a front group comprises baflle-plates constructed as set forth above, and the second grouxi is arranged between the barrel-muzzle and the front group, and comprises a plurality of baffle- 96 plates which are each of fiat construction, one or more of wdiich have each a shallow arcuate peripheral recess wliich. when in its position of use, lies in the lower part of the silencer, 100... 

A 56-year-old chronic intranasal cocaine abuser with a visible nasal defect presented with a hole in the roof of his mouth. He had been reportedly drug free for 2 weeks. He had an oronasal fistula with adjacent black necrotic areas and erosive destruction of the nasal septum, turbinates, and antrum, with mucoperiosteal thickening of the sphenoid and maxillary sinuses. Treatment included antibiotics and a prosthesis plate construction... 

The cryostat consists of a stainless steel, vacuum-jacketed, flanged vessel with an inside diameter of lOj in. and a maximum depth of 22 in. The outside diameter of the cryostat is 12h in. with an overall height of 24 in. The flange is 1 in. thick, 17 in. in diameter and contains two grooves for 12 and 13 in. 0-rings. The cryostat is bolted to a stationary top plate constructed of 1-in. stainless steel, from which all equipment contained within the cryostat is suspended. 

Design considerations include the proximity to other metallic structures and existing CP systems, the type of grounding, the estimated remaining service life of the tank, the type and temperature of the stored product, the amount of product stored, the cycling rates, the method of tank bottom plate construction, the type of tank foundation, the type of secondary containment, if any, and the backfill soil characteristics. 

The value of y depends on the plate construction. This can be demonstrated by the cross section of two plates of different designs (Fig. 4.52). 

Schematic representation of three tubular plate designs (a) cylindrical tube cross section (b) elliptical tube cross section (c) strap grid tubular plate construction.

Bottom openings (1) baffle plate construction (see EN 60950), or (2) metal wire mesh not greater than 2x2 mm and a wire diameter of not less than 0.45 mm, or (3) size and spacing of holes in metal bottoms (i.e., 2-mm-diameter hole max. x 2 mm spacing min. for a 1-mm min. thick metal bottom). 

Hardening is not necessary, and chrome plating is not customary. For large-volume parts with a content of 4 cu yd (3 cu m) and up, welded machined steel plate construction can be considered. Cast metal is of no value for the mold bases. Given the right care, the life of steel molds is the longest, at over 10 parts per mold. Inserts subject to wear and tear have to be either refurbished or exchanged at intervals of 10 or 10 cycles (Table 4-10). 

Although many older presses were of cast-iron or cast-steel construction, most modem presses are fabricated using welded-steel-plate construction. Welded-plate constmction provides readily available raw material for an efficient, economical, and rigid structure. Thermal stress relieving is recommended after welding to provide dimensional stability to the weldments. 

Lithium ion cells serve the smaU-sealed rechargeable battery market and compete mainly with the Ni-Cd and Ni-MH cells for the various applications. The Li-Ion cells are available in cylindrical and prismatic format as well as flat plate constructions. The cylindrical and prismatic constructions use a spiral-wrap cell core where the ceU case maintains pressure to hold and maintain compression on the anode, separator, and cathode. The lighter-weight polymer constructions utilize the adhesive nature of a polymer/laminate-based electrolyte to bond the anode to the cathode. 

---