Product Size and Shape

Product size is limited to available equipment that can handle the size and pressure as well as other processing requirements. Also involved are factors such as packaging and shipment to the customer. The ability to achieve specific shapes and design details is dependent on the way the process operates. 

Can be easily integrated into the structural member Compact, space-saving form Takes over other functions like bearing, spring cushioning, fixing 

Higher forces can also be transmitted with proper designing 

Small number of individual parts Assembly of a construction system with little expenditure of production facilities and time 

The fixing of the joined parts is weaker than in welding, bonding, and screw joining 

---

Prices for the different material groups (F —F ) are largely influenced by product size and shape and the quantity of production. Apart from product shape, the main price-determining factor is the performance factor K Prices for the powder, a sintered anisotropic ring, and a sintered anisotropic segment are roughly on the order of 1, 2, and 5, respectively. 

We have seen previously shape-selective catalysis by ZSM-5 in the conversion of methanol to gasoline (Chapter 15).-7 Other commercial processes include the formation of ethylbenzene from benzene and ethylene and the synthesis of p-xylene. The efficient performance of ZSM-5 catalyst has been attributed to its high acidity and to the peculiar shape, arrangement, and dimensions of the channels. Most of the active sites are within the channel so a branched chain molecule may not be able to diffuse in, and therefore does not react, while a linear one may do so. Of course, once a reactant is in the channel a cavity large enough to house the activated complex must exist or product cannot form. Finally, the product must be able to diffuse out. and in some instances product size and shape exclude this possibility. For example, in the methylu-uon of toluene to form xylene ... 

In spite of the inherent limitations of all growth agglomeration techniques, which are also valid for discs, the latter piece of equipment has attracted considerable interest during the short time since it was first introduced. Reasons for this are the unusually good and easy control of the performance of the apparatus and the uniform product size and shape that can be obtained. To further improve these conditions a number of modified disc configurations have been proposed and some are being used to achieve special effects. 

The capacities of comminuting machines are best discussed when the individual types of equipment are described. The fundamentals of product size and shape and of energy requirements are, however, common to most machines and can be discussed more generally. 

Yao J, Wang C, Lim EWC, Bridgwater J, 2006, Granular attrition in a rotary valve Attrition product size and shape. Chemical Engineering Science, 61, 3435-3451... 

Pressing and sintering together determine the size and shape of the final product, but these are not well controlled with respect to the critical parts which determine the airgap in the magnetic circuit. For that reason a finishing touch by machining is necessary. 

The general manufacturing scheme for phosphate salts is shown in Figure 11. Condensed phosphates are prepared from the appropriate orthophosphate or mixture of orthophosphates, so the preparation of orthophosphates must be considered first for the manufacture of any phosphate salt. Phosphoric acid is neutralized to form a solution or slurry with a carefully adjusted acid/base ratio according to the desired orthophosphate product. The orthophosphate may be recovered either by crystallization from solution, or the entire solution or slurry may be evaporated to dryness. The dewatering (qv) method is determined by the solubihty properties of the product and by its desired physical properties such as crystal size and shape, bulk density, and surface area. Acid orthophosphate salts may be converted to condensed phosphates by thermal dehydration (calcination). 

The most commonly measured pigment properties ate elemental analysis, impurity content, crystal stmcture, particle size and shape, particle size distribution, density, and surface area. These parameters are measured so that pigments producers can better control production, and set up meaningful physical and chemical pigments specifications. Measurements of these properties ate not specific only to pigments. The techniques appHed are commonly used to characterize powders and soHd materials and the measutiag methods have been standardized ia various iadustries. 

Slate. Used for hundreds of years, slate comes from different geographical areas and varies in color and weight. Slate (36) is easily spHt to size and shape the most common is 4.76-cm (3/ 16-in.) thick and can weigh 31.71 kg/m (650 lb/100 ft ) or more. Imitation products of mineral fiber and cement stimulate its durabiUty and style. 

Generally, Httle is known in advance concerning the degree of homogeneity of most sampled systems. Uniformity, rarely constant throughout bulk systems, is often nonrandom. During the production of thousands of tons of material, size and shape distribution, surface and bulk composition, density, moisture, etc, can vary. Thus, in any bulk container, the product may be stratified into zones of variable properties. In gas and Hquid systems, particulates segregate and concentrate in specific locations in the container as the result of sedimentation (qv) or flotation (qv) processes. 

A catalyst manufactured using a shaped support assumes the same general size and shape of the support, and this is an important consideration in the process design, since these properties determine packing density and the pressure drop across the reactor. Depending on the nature of the main reaction and any side reactions, the contact time of the reactants and products with the catalyst must be optimized for maximum overall efficiency. Since this is frequendy accompHshed by altering dow rates, described in terms of space velocity, the size and shape of the catalyst must be selected carehiUy to allow operation within the capabiUties of the hardware. 

In the production of particleboards, mixtures of particles are often used as raw material. The particles differ in size and shape. A particle size distribution can be done by screening, and two of the three dimensions of the particle must be smaller than the standard measure of the screen to be passed. An exact screening of the particles to their size is only possible for rather similar shapes. Particles, however, can widely differ in shape. For a simplifying description, the shape is assumed as a flat square of length I, width b and thickness d for medium and coarse particles and cubic for the fines. The mechanical screens are graded in... 

Solid particles have a distinct form, which can strongly affect their appearance, product quality and processing behaviour. Thus, in addition to chemical composition, particulate solids have to be additionally characterized by particle size and shape. Furthermore, particles can be generated at any point within the process. For example, nucleation occurs within a crystallization process and large particles are broken down to numerous smaller ones in a comminution process or within a drier. 

Sada, E., Kumazawa, H. and Aoyama, M., 1988. Reaction kinetics and controls of size and shape of geothite fine particles in the production of ferrous hydroxide. Chemical Engineering Fundamentals, 71, 73-82. 

---