Autoclave technology

Microbial lethality from steam sterilizatiem is a function of two parameters, temperature and time. The choice of a cycle is ultimately dependent upon the heat-stability of the product, the type of primary container, the knowledge of heat penetration into the product, the autoclave technology available, and the knowledge of the microbiological contamination prior to sterilization. However, the pharmacopoeias (particularly the USP) offer some sound general advice to the selection of criteria. 

The use of autoclave technology to produce composite members allows for the manufacturing of sheets with very high mechanical properties compared to the more traditional and cost-effective technologies described herein (Fig. 2.5). 

An independent development of a high pressure polymerization technology has led to the use of molten polymer as a medium for catalytic ethylene polymerization. Some reactors previously used for free-radical ethylene polymerization at a high pressure (see Olefin polymers, low density polyethylene) have been converted to accommodate catalytic polymerization, both stirred-tank and tubular autoclaves operating at 30—200 MPa (4,500—30,000 psig) and 170—350°C (57,83,84). CdF Chimie uses a three-zone high pressure autoclave at zone temperatures of 215, 250, and 260°C (85). Residence times in all these reactors are short, typically less than one minute. 

The oldest technology involved in the elastomer blending and vulcanization process is essentially a temperature controlled two roll mill as well as internal mixers followed by an optimum degree of crosslinking in autoclave molds (compression, injection, etc.) in a batch process or in a continuous process such as continuously heated tube or radiated tubes. A few examples of laboratory scale preparation of special purpose elastomeric blends is cited here. 

The reduction in the numbers of incinerators and the limitations of autoclaves have created the need for alternative medical waste treatment systems. Currently, there are over 40 such technologies available from greater than 70 manufacturers within the United States, Europe, the Middle East, and Australia. While these systems vary in their treatment capacity, the extent of automation, and overall volume reduction, all alternative technologies utilize one or more of the following methods (1) heating the waste to a minimum of 90 to 95°C by means of microwaves, radio waves, hot oil, hot water, steam, or superheated gases (2) exposing the waste to chemicals such as sodium hypochlorite (household bleach) or... 

Figure 11.31 Photograph of a sixfold autoclave bench developed by Parr Instrument Company (www.par-rinst.com). The apparatus was built in 1988, similar technologies that Parr commercialized in the early 1990s were already fully computer controlled.

There are several variations of HIER. Many laboratories have attempted to improve the original method by altering the buffer solutions as well as the source and mode of heating. Currently, the most popular HIER technologies use stainless steel or plastic pressure cookers, microwave ovens, or autoclaves as the heat source and low-molarity buffers with acidic or alkaline pR (6,7,9-12). 

Zotefoams has introduced a new 100% PP foam called Propozote, produced using unique crosslinking technology using an autoclave at a higher temperature... 

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