Pressurised steam

Of the methods discussed for decontaminating a freeze-drier, in the absolute sense only pressurised steam can be regarded as a sterilant. Since 1970, the use of pressurised steam for sterilising pharmaceutical freeze-driers has become standard and freeze-drying manufacturers are conversant with the problems associated with the fabrication of steam-sterilisable machines. Exhaustive literature exists detailing the temper-ature/pressure relationship required to destroy individual micro-organism species and these conditions can be readily achieved within the freeze-drier. 

In addition to its sterilising action, steam has a number of other properties which make it virtually an ideal cleaning agent/biocide and these may be summarised as  

1 Disadvantages of using pressurised steam include the following 

2 The use of pressurised steam for decontaminating a freeze-drier The advantages of using pressurised steam as outlined above strictly apply only when sterilising freeze-driers prior to processing parenteral products. When it is intended to use pressurised steam to decontaminate a freeze-drier which has been used to dry hazardous materials, a potentially serious disadvantage should be considered related to the need to raise the 

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Most of the considerable volume of published work on the behaviour of zirconium relates to its use in nuclear reactors in contact with water or steam, e.g. in pressurised steam the control of oxidation by use of boric acid has been reported . The reader is advised to consult the reviews on this important aspect of the subject cited under References 76 and 77. 

No there will not be vacuum, but lower pressure than at TDC. Still pretty high. I think Aubug already showed that the water mist that came through the carburettor would flash to steam before TDC due to compression alone. So you most probably have pressurised steam in the cylinder when it s firing. 

The direct sterilisation of particulafe solid foods in a gas-solid fluidized bed was proposed as long ago as 1968 by Lawrence et al. (1968) who sterilised wheat flour in steam-air mixtures at the pilot scale. However, Jowitt (1977) described an atmospheric pressure process for fhe sferilisation of canned foods in which the cans are immersed in a fluidized bed of inert particles. This has a number of advantages compared to the conventional retorting process using pressurised steam or hot water ... 

A number of phosphate and thiophosphate esters are of limited thermal stability and undergo highly exothemiic self-accelerating decomposition reactions which may be further catalysed by impurities. The potential hazards can be reduced by appropriate thermal control measures. An example is the substitution of hot water at 60 C for pressurised steam to melt a solid phosphate ester, which on adiabatic calorimetric examination was found to have a time to maximum decomposition rate of 6 h at 110° but 11 h at lOO C [2]. The combined use of vapour phase pyrolysis to decompose various phosphoms esters, and of GLC and mass spectrometry to analyse the pyrolysis products, allowed a thermal degradation scheme to be developed for phosphorus esters [3]. Individually indexed compounds are ... 

The temperature of pressurised steam is above 100 °C. A pressure cooker ailows the safe production of pressurized steam, which then cooks food faster than the conventionai method in which food is simply immersed in boiling water at 100 °C in an open pot. 

The remaining faults are analysed using a modified version of LOFTRAN, which describes the reactor thermal kinetics, reactor coolant system (including natural circulation), pressuriser, steam generators, and feedwater system responses and computes pertinent variables, including the pressuriser pressure, pressuriser water level, and reactor coolant average temperature. 

Dense Si diffusion coatings seem difficult to obtain by both of the processes investigated. The possible formation of iron dichlorides, which competes with the formation of silicon chloride [8], may be an explanation for the porous coatings obtained. Furthermore, the potential application of silicaforming alloys in power plants needs to be verified in detail, since silica might dissolve in pressurised steam at high temperature. 

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