Despite advances in technology, the importance of steam in NHS hospitals cannot be undervalued. Nevertheless, according to steam system specialist, Gary Sowerby CEng FEI, ‘it is becoming a feature which, like the tiger, is facing extinction’. However, as he puts it, ‘it is still of vital importance when we discuss the central role of steam in the hospital steriliser’. In this article, he aims to provide what he dubs ‘a vital understanding of the provision of efficient and good quality steam to the steriliser plant’.
Steam should be provided from a source which is capable of supplying suitable steam at the correct steam pressure. Boilers should all be operated at their design pressure, and pressure control equipment used to provide the correct pressure required for the steam-using plant. It is essential that ‘Good boiler house practice’ is followed to prevent high water levels and the Total Dissolved Solids (TDS) which can lead to priming and carryover.
A boiler must not be loaded to the extent that excessive pressure drop occurs during peak load periods. This will result in carryover, and possibly priming, giving wet steam. Ideally, the boiler feedwater temperature should be maintained at as high a level as possible, and not allowed to drop below 80˚C. If necessary, the boiler feedwater should be heated by means of either a correctly sized steam coil, or direct steam injection system. A minimum dryness fraction of approximately 0.90 is required.
Distribution systems
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