END SEAL

The invention relates to end rotor seals installed in pump assemblies for the separation of media or pressure difference. The invention can be utilized in the design of pumps used in nuclear power stations, particularly main circulation pumps. The invention is aimed at increasing the reliability of the unit, as well as improving the manufacturability of components and the installation of the seal.In order to achieve the corresponding technical results, a multistage end seal design is proposed, comprising consecutively arranged working stages and an end stage, each of which comprises a rotor element arranged on a shaft, and a spring-loaded axially displaceable stator element connected to said rotor element and sealed with respect to the housing by means of sealing rings, wherein low-and high-pressure chambers of the working stages are consecutively connected by throttle openings in the stator element, which is configured so as to carry out the functions of an axially displaceable stepped piston which is sealed