plumbing London Gaskets - what are they?
Gaskets are mechanical seals, usually formed like a ring and used for sealing of flange joints. In general, gaskets should not be reused. Various types of gaskets are available depending upon their construction, materials, and features. 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. Thus, the hardness of the gasket is kept less than the hardness of the groove to achieve coining i.e. bringing two metal surfaces of different hardness so tightly together that the softer surface deforms to match harder surface exactly in shape and finish.
Źródło: https://en.wikipedia.org/wiki/Piping_and_plumbing_fitting
Scope of work undertaken by small hydraulic
Small plants hydraulic predominantly take orders for minor plumbing work. They can be associated with connecting new sanitary facilities or carrying out small repairs. All such work can be carried out also by plumbers self-employed. You just have to reckon with the fact that the services contract with an independent plumber probably will prolong the work carried out. However, this should not affect their quality, and sometimes it turns out that the plumber running his own business applies doubly to perform the outsourced tasks themselves. They may rely on both the exchange of a faulty seal and at the connection of the new tap.
Worth to know
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. Beginning with an Act passed that year that was to prohibit the dumping of excrement into the river. 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. Proposals to modernise the sewerage system had been made during 1856, but were neglected due to lack of funds. However, after the Great Stink of 1858, Parliament realised the urgency of the problem and resolved to create a modern sewerage system.
Źródło: https://en.wikipedia.org/wiki/History_of_water_supply_and_sanitation