A procedure is described for calculating the sizes of interdependent pieces of equipment which minimize the capital Investment of a batch processing plant. Power-law-type cost expressions are presented for both true batch and semicontinuous units and combined to form an over-all objective function. Ordinary calculus is used to establish necessary conditions for optimum equipment sizes. These conditions lead to a set of one-dimensional algebraic equations, solvable by simple iterative techniques. A sample calculation illustrates the procedure and demonstrates the savings realizeable in equipment costs.

argument, the descending solids from A to B add gas to the leaving stream, Y. Since roughly the same amount of gas is gained at B as lost at C, a material balance will show that flow X agrees with flow Y. But this is not the flow through the experimental section.Since Professor Happel used a large volumetric flow rate of gas compared to that of solid, only a small error is made in assuming that flow X or Y is the flow through the bed (maximum error of about 3% for his run No. 104). However, if we would have used this procedure with our system of fine particles, our error would have been ridiculously large. This is why we used a tracer technique (tagging the flowing molecules in the experimental section) to measure flow rates.4. Dr Happel's final question asks what provision was made to counter gas leakage with the solids (the equivalent of gas entrainment from A to B, or from C to D). We did not make any such provision, and we do expect that significant amounts of gas were so entrained. Note that equalizing pressures up and dowpstream does not guard against gas leakage. It actually guarantees such leakage.We measured the actual gas flow within the experimental section by tracer methods.

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In the manufacture of small precise-to-form forgings for the aero-space industry, components, many of identical shape, in a wide range of alloys are processed at the same time. Methods of alloy classification employed have developed from chemical spot checks up to automatic read-out spectrographs, which produce a high spectrum dispersion. This technique necessitates highly skilled operators and introduces a mental fatigue factor. This paper describes the development of a direct reading automatic read-out unit capable of operation by personnel having a minimum of training. A special counter-electrode and feed system was required. Due to the variation in surface finish and geometric shape of the forgings, the simple setting procedure envisaged was not practical and use of a trimming standard was required as an integral part of the procedure. The unit has been in production for over two years and has completed over 900 000 alloy classifications.