摘要:

AbstractDigital process control systems. We are currently witnessing a technical revolution instigated by the microprocessor, which is considerably changing our methods of process control and the design of control rooms. The modern control room presents an entirely different man‐machine interface. CRT's with keyboards and/or light pens for plant control and operation are now to be found instead of instrumental boards. This paper describes the architecture and mode of operation of this new generation of process control system

ISSN:0009-286X    

DOI:10.1002/cite.330550402

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractDevelopments in single worm extruders. Starting from the multifarious chemical engineering tasks to be mastered in production and processing of plastics, the single worm extruders nowadays used for this task (plastifying extruders, melt‐exit extruders, degassing extruders, and cascade systems) are presented and the associated foci of development are mentioned. It becomes clear that further reductions in the price/performance relation of such plant will most likely be accomplished by a systematic analytical description of the mechanical/thermal unit process of conveying of solids in the individual functional zones, of plastifying, mixing, and homogenization, and pressure build‐up. The knowledge accruing from such model considerations leads to extruder sections which are optimized energetically and engineeringwise (grooved entry, intensive heat‐up, exit zones) which in turn satisfy requirements for higher mass throughputs and improved product quality. Similar analyses of the extruder/tool combined system can serve as a basis for process models for fully automated operation of extruders by means of microcomputer systems so far used to control individual operating parameters and acquisition of operating

ISSN:0009-286X    

DOI:10.1002/cite.330550403

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractDevelopment trends in electrochemical process engineering. Important electrochemical production processes have recently been crucially modified or newly developed and this opened new horizons for the future of industrial electrochemistry. The thrust of this development is discussed in three selected areas: alkali chloride electrolysis, water electrolysis, and organic electrosynthesis. Important past steps are the invention of the dimensionally stable anodes, the development of the cation exchange membrane and membrane electrolysis, the successful testing of zero gap cells, SPE electrolysis and the economic use of two phase electrolytes. These successes have arisen mainly from an improved knowledge and understanding of the fundamental principles of electrochemical engineering.

ISSN:0009-286X    

DOI:10.1002/cite.330550404

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractScale‐up of agitated vessels in the case of suspensions. In the scale‐up of agitated vessels a decrease of specific power input ε is recommended in the case of suspensions. Up to now it has been assumed that turbulence is the reason for this decrease. This paper shows that there may also be a contribution due to decreasing wall areas causing less wall shear stresses and moreover a reduction of circulation due to lower cross‐sectional areas per unit volume of the threads of flow. In the case of so‐called „complete suspension”︁ according to the „1‐s criterion”︁, two mechanisms can be distinguished: On the one hand we have a lifting of solid particles without, and on the other hand such a lifting with formation of bulk accumulations of solids on the bottom of the vessel. In the first case, scale‐up can be done as for a homogeneous distribution of the solid material. The specific power input ε is ∼ μ0up to ε ∼ μ−1with the scale‐up factor μ. In the second case (formation of dense solids clouds) a

ISSN:0009-286X    

DOI:10.1002/cite.330550405

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550406

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractMembranes in medical process engineering. Synthetic membranes not only represent the essential components of an artificial kidney or an artificial lung but are also used as wound dressing and in systems for controlled release of drugs in certain long‐term therapeutic measures or as part of an artificial pancreas. By far the greatest present economic significance of membranes is their use in the so‐called artificial kidney. Considerable cost saving would result if patients could undertake „home dialysis”︁. This requires the development of new, simpler artificial kidneys and thus higher‐performance membranes. The latest trend in „artificial kidneys”︁, the so‐called method of „hemodiafiltration”︁ warants special mention. The separation process is no longer effected only by diffusion but also by convection, i.e. the driving force is the pressure difference between the two sides of the membrane. This paper addresses problems encountered in the development and use of membranes in medicine, recent applications such as the controlled release of active components, or plasma separation, and demonstrates the potential

ISSN:0009-286X    

DOI:10.1002/cite.330550407

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550408

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCleaning and disinfection in dairy plant – State of the art. Cleaning and disinfection in dairy plant constitute an integral part of processing. Plant and pipework must therefore be constructed with a view to cleaning and disinfection. Cleaning and disinfection as unit processes in food processing are affected by the following factors: nature of contaminants or microorganisms, design of plant, chemical factors, mechanical factors, temperature, and time. The removal of contaminations occurring in practice can be located between two extremes. In the most favourable case we are concerned with molecular solubility with diffusion under the action of a concentration gradient through the interface, and the process can be described in terms of mass transfer. The least favourable case is encountered when there is no solubility and contamination is by macroparticles which are joined to each other and to the wall by strong forces which can only be overcome by flow forces. Removal of the particles is then subject to a statistical distribution; the particles bound most firmly require the longest time for their removal. The process can be described by a logarithmic time la

ISSN:0009-286X    

DOI:10.1002/cite.330550409

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550410

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330550411

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY