As recently as the late 19th century sewerage systems in some parts of the rapidly industrializing United Kingdom were so inadequate that water-borne diseases such as cholera and typhoid remained a risk. From as early as 1535 there were efforts to stop polluting the River Thames in London.
Leading up to the Industrial Revolution the River Thames was identified as being thick and black due to sewage, and it was even said that the river ?smells like death.?24 As Britain was the first country to industrialize, it was also the first to experience the disastrous consequences of major urbanisation and was the first to construct a modern sewerage system to mitigate the resultant unsanitary conditions.citation needed During the early 19th century, the River Thames was effectively an open sewer, leading to frequent outbreaks of cholera epidemics.
To define and secure boilers safely, some professional specialized organizations such as the American Society of Mechanical Engineers (ASME) develop standards and regulation codes.
For instance, the ASME Boiler and Pressure Vessel Code is a standard providing a wide range of rules and directives to ensure compliance of the boilers and other pressure vessels with safety, security and design standards.5 Historically, boilers were a source of many serious injuries and property destruction due to poorly understood engineering principles.Thin and brittle metal shells can rupture, while poorly welded or riveted seams could open up, leading to a violent eruption of the pressurized steam.
Collapsed or dislodged boiler tubes can also spray scalding-hot steam and smoke out of the air intake and firing chute, injuring the firemen who load the coal into the fire chamber.Extremely large boilers providing hundreds of horsepower to operate factories can potentially demolish entire buildings.
Gaskets are mechanical seals, usually formed like a ring and used for sealing of flange joints.
The following are the type of gaskets commonly used: Non-Metallic Gaskets (ASME B 16.21) Spiral-Wound Gaskets (ASME B 16.20) Ring Joint Gaskets (ASME B 16.20) Non-Metallic Gaskets are used with flat face or raised face flanges.
Spiral-Wound Gaskets are used with raised face flanges.
They are available with an inner ring and outer ring, which is also known as the cantering ring.Ring Joint Gaskets are used with Ring Type Joint (RTJ) flanges. They are available in octagonal or oval cross sections. A very high surface stress is developed between an RTJ gasket and the flange groove when RTJ is bolted up in a flange. This leads to plastic deformation of the gasket.