Dust-free design

Turboexpanders and Process Applications Dust-Free Design... 

An alternate design has fixed jacketed trays for indirect heating. Scrapers attached to the central shaft drop the material from tray to tray. Like the rotating tray equipment, this equipment is limited to free flowing materials, but has the advantage of being essentially dust free. 

Airborne particles are one important source of sample contamination. Therefore, the laboratory must enable samples to be treated and measurements to be carried out in a satisfactorily dust-free environment. Improvements in existing laboratories can be obtained by installing a laminar flow hood, but optimal improvement involves the design of clean rooms in which air is pumped through a dust-stop prefilter and then forced by a blower through an absolute filter inside the working... 

All operations (cleaning, filtration, acidification and sample handling) were carried out in a specially designed Class 100 room, either fitted in a standard 20 ft transport container which was fully equipped as a chemical laboratory or in a room transformed as such on board of the research ship. All operations with the sample were performed in a closed system, except for the sample acidification and the filling of the bottles, which were performed in a laminar flow clean bench inside the clean room. All personnel working in the clean area used polythene gloves, dust-free garments and shoe-covers. 

With insufficient data to design the reactor, we snggest this design be nsed only for the sulfidation step in the overall operating scheme shown in Fignre CS6.6. It is necessary that a dust collector (not shown in the figure) be used to ensure dust-free feed to the regeneration system. 

Automatic systems for precipitation sampling are usually designed so that it is possible to take dust-free samples. The automatic mechanism of commercially produced systems is focused on opening of the sample containers during rain and closing in the periods without rain. The lid of the system is controlled by a switch sensitive to the very first rain drops or snow flakes. Usually, the conductivity of rain water is utilized which connects two insulated points with opposite electric charges on an inclined and slightly heated plate. 

For the manufacture of sterile drugs, separate enclosed areas specifically designated for the purpose shall be provided. These areas shall be provided with air locks for entry and shall be essentially dust free and ventilated with and air supply. For all areas where aseptic manufacture has to be carried out air supply shall be filtered through bacteria retaining filters (HEPA filters) and shall be a pressure higher that the adjacent areas. The filters shall be checked for performance on installation and periodically thereafter, and records thereon shall be maintained. 

The mode of operation of an industrial dust collector may in very simplistic terms be compared with that of a traditional domestic vacuum cleaner i.e. dust-laden air is drawn by vacuum on to the surface of the dust bag , the filter medium retains the dust whilst the dust-free air is expelled into the atmosphere. In an industrial unit, the filter media comprise either woven or non-woven materials, and are normally sewn in the form of tubes (usually referred to as filter sleeves), flat enveloped shaped bags, or cartridges of various design e.g. flat panel or pleated. 

The use of properly designed relief panels or free floating vessel covers are usually effective for dust explosions in silos tanks, filter housings, and the like. The design basis has been pre dousIy discussed. 

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