Isolator positive-pressure

While with-in the mobile x-ray system, the waste in the sampler, is contained within a replaceable (and disposable) polyvinyl chloride (PVC) sleeve with a wall thickness of approximately 0.2-inches and a sealed bottom. It was anticipated that the PVC tube or sleeve would, with use, become highly contaminated with waste residues which drip of fall-off the sampler. The sleeve is coated with a conductive coating to prevent static electricity buildup . There are no sources of ignition in this sealed spare. The sampler (and waste) is coupling which includes a positive pressure gasket. This barrier is further isolated by a second barrier consisting of an epoxy coated aluminum sleeve also sealed-off from the main x-ray cabinet and PVC sleeve. There are also no potential sources of ignition in this isolated secondary space as well. 

Particularly reasonably priced explosion isolation of systems involves the use of a relief pipe with which the flow direction can be diverted by 180°. It prevents flame jet ignition with precompression in constructionally protected equipment. If suction is present, explosion propagation can occur. To prevent this, the use of an additional extin-gui ing barrier or a rapid-action gate valve is necessary. If a diverter is installed where positive pressure feed is given, then the diverter is, in general, safe against an explosion propagation. 

Under an inert atmosphere, a solution of the substrate in benzene was added to a slurry of freshly purified CuCl (5 mol%), Me2PPh (6 equiv./Cu), and t-butanol (10 equiv./Cu) in benzene (final concentration 0.4-0.8 M in substrate). After degassing with one freeze-pump-thaw cycle, the suspension was placed under a slight positive pressure of hydrogen and allowed to stir until completion, as monitored by TLC. The product was isolated and purified as described above. 

This chapter covers examples of system modifications made to prepare for maintenance. Each unwise modification created equipment damage. These incidents were simple changes intended to isolate, protect, clean, or clear equipment, and the methods chosen created problems. In some cases equipment was subjected to partial vacuum or positive pressure beyond the tolerable design limits. 

Sterility testing requires a strict control of microbial contamination challenge from outside the controlled environment, but not of the particulate contamination liberated by the process itself. Hence, a positive-pressure isolator in a controlled environment, using... 

Isolators for aseptic operations work at positive pressures relative to the general environment. Up-to-date isolator technologies are most often based on containment within Aexible transparent PVC tents. Sterilization of internal surfaces is by peracetic acid or hydrogen peroxide fumigation. Positive pres-... 

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