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.
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.
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
Plumbing equipment includes devices often hidden behind walls or in utility spaces which are not seen by the general public.It includes water meters, pumps, expansion tanks, backflow preventers, water filters, UV sterilization lights, water softeners, water heaters, heat exchangers, gauges, and control systems. Specialized plumbing tools include pipe wrenches, flaring pliers, pipe vise, pipe bending machine, pipe cutter, dies and joining tools such as soldering torches and crimp tools. New tools have been developed to help plumbers fix problems more efficiently.
For example, plumbers use video cameras for inspections of hidden leaks or problems, they use hydro jets, and high pressure hydraulic pumps connected to steel cables for trench-less sewer line replacement.Źródło: https://en.wikipedia.org/wiki/Plumbing#Equipment_and_tools