摘要:

AbstractInterfacial problems in solid/liquid separation. Mechanical solid/liquid separation is one of the unit operations of chemical engineering, which is far from having been mastered theoretically. This is because interfacial forces play such a pronounced role in this process step, and these forces have so far largely withstood scientific investigation. The present article enumerates the problems involved, and necessarily presents more open questions than ready answers.

ISSN:0009-286X    

DOI:10.1002/cite.330580302

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractSafeguarding of chemical production plant by means of control engineering. Control equipment is becoming increasingly important for safeguarding of plant. According to VDI/VDE 2180, sheet 3, control equipment is classified as operational equipment, as monitoring equipment, or as protective equipment. Operational and monitoring control equipment serves the proper operation of plant in its correct state or in a faulty but still acceptable state. Protective control equipment is intended to prevent occurrence of an unacceptable faulty state of the plant. It is helpful if the control equipment is classified at an early stage of planning. Preferably the protective control equipment should be considered separately from the other control equipment. It is then possible to design it in such a way that its behaviour in the event of faults can be clearly defined. A distinction is made between active faults (or functiontriggering faults) and passive faults (or function‐inhibiting or blocking faults). An active fault reduces the availability of chemical plant for production by inadvertent shut‐down. Passive faults of protective equipment prevent triggering of the protective function, even though the conditions for triggering are fulfilled. They adversely affect the safety of the plant. Passive faults of control equipment must therefore by prevented or kept under control. A selection of appropriate measures for achieving this is presen

ISSN:0009-286X    

DOI:10.1002/cite.330580303

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractPumps and compressors for high pressures – strength, seals, wear. In high pressure processes pumps and compressors are used for the pressure range of 100 to 4 000 bar. Very careful design is necessary because of the extreme mechanical demands. The special features of high pressure technology are explained. The methods used for generating high pressures – displacement or fluid flow machine – impose design limitations, partly by the final temperature, Mach number, material fatigue, or vibrations. A survey of typical high pressure pumps and compressors shows the range and limitations of application. There is a definite trend to leak‐free systems. The best design of thick‐walled components with pulsating pressureload avoids grooves, requires smooth surfaces, and uses tough, clean, and high‐strength steels. The various designs of dynamic seals are explained and the state of the art is depicted. Detailed reference is also made to the exceptionally difficult wear problem of oscillating pump valves with abrasive

ISSN:0009-286X    

DOI:10.1002/cite.330580304

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractState of the art in continuous feeding of solids and liquids. After defining the characteristics of continuous gravimetric feeding systems, the author lists the aims and reasons for the application of these methods in one‐ and multiple component systems. We can distinguish between gravimetric feeders with positive gross weighing and negative net weighing. The latter principle has advantages in operation, and is embodied in the weight‐loss weigh feeders. A synoptic chart of the various gravimetric feeder designs shows the nature and the method of acquisition of the controlled value and also classifies the fields of application as to feed range and material characteristics. When designing a feeder, the weight and volume of material flow, the characteristics of the weight resolver and of the metering device have to be considered. Latest developments of the principal components of weigh feeders are illustrated by examples, such as metering devices for solids with poor flow properties, combination of feeding and pneumatic conveying systems, headload compensation with weight‐loss weigh feeders, feeding with high instantaneous accuracy, gravimetric feeding of liquids at small feed rates, set point and ramp programming, and monitoring of the bulk density of the mat

ISSN:0009-286X    

DOI:10.1002/cite.330580305

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractClean room technologyis essentially concerned with the control of particulate contamination. Sources of contamination are: air, work benches, personnel, machines, services. The control of airborne particles has already reached a high level. The cleanliness of process equipment can be further improved by the integration of laminar flow units. Cleanliness requirements and particle analysis meanwhile even cover liquidborne submicron particles. Classification systems for the cleanliness of liquids are in preparation. The contamination of powders results from different particle sources over the whole production process. The quality factor „particle control”︁ is in tended to prevent trouble and improve the economic efficiency and reliability of an increasing number of proc

ISSN:0009-286X    

DOI:10.1002/cite.330580306

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330580307

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330580308

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330580309

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330580310

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330580311

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY