Rings of mechanical seals
An important role in the design of mechanical seals is played by elements directly involved in the process of friction, it is O-rings of mechanical seals. The sealing mechanism, regardless to the mechanical seal design, assumes contact on the flat end of these rings forming a friction pair. From the point of view of assemble reliability, it is extremely important to ensure the operation of a friction pair with the lowest friction and wear coefficients in each particular case. Ring designs and materials are determined by a large set of operational, design and process parameters. Among the main indicators that determine reliability of a friction pair are:
- chemical resistance of the material in the medium to be sealed;
- wear resistance of material combination of friction pair;
- thermal conductivity of the material (heat removal from the friction zone, reduction of the temperature gradient and, accordingly, temperature stresses and deformations);
- high modulus of elasticity (the resistance to force deformations);
- low temperature coefficient of linear expansion;
- manufacturability (the possibility to provide a high quality surface treatment).
Ceramic materials and cemented carbide meet the above requirements, which makes them widely used for the production of mechanical seal rings. The most widely used reactive silicon carbide, sintered silicon carbide, aluminum oxide and cemented carbide. In a number of cases, as a material of the friction pair, various versions of carbon materials (impregnated graphites, etc.) are used together with ceramics.
All types of ring sizes for mechanical seals are produced in series.
Non-standard rings are made according to customer’s drawings. It is possible to apply grooves on rings for dry gas-dynamic seals.