Wikipedia about Gaskets
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
The scope of work performed by hydraulic emergency hydraulic
Emergency hydraulic deals with the repair of sudden and serious failure of hydraulic. Employees pogotowania hydraulic also provide victims advice on how they can protect your house or apartment before more flooding. Notification of such a failure of the hydraulic, which may require emergency hydraulic arrival is done by phone, and the arrival of such an emergency can occur within several minutes. In the phone book you can find phone numbers for such branches emergency hydraulic, which are open around the clock and seven days a week, including holiday periods. But keep in mind that employees emergency hydraulic refuse to come to such repairs, which need not be performed immediately.
hydraulic nature of the work performed in the city
City of hydraulic engaged in the execution of various works. Some of them are contracted by the city authorities and owners of various public buildings, and others by owners of private flats and houses. Therefore, the scope of hydraulic works performed in cities is very wide. It includes both Pip drains and supervising the work performed after the flooding of the city by heavy rains and repair of hydraulic failure in flats and houses and installation of new sanitary facilities. Such an installation can be performed by plumbers working alone or working in the company hydraulic system. While the work is carried out after heavy rains need to rent a large company hydraulic system.