The rotating part of the seal is fixed on the pump shaft and rotates in the liquid during pump operation.
The rotating part of the seal is fixed on the pump shaft and rotates in the liquid during pump operation. The compression of the rubber bellows (8) between the shaft (9) and one of the two torque transmission rings (10) fixes the rotating part to the shaft. The spring (6) transfers the torque between the torque transmission rings (5, 10). The rotating seal ring (4) is mounted together with the rubber bellows (8). The torque transmission ring (5) compresses the rubber bellows (8) to the rotating seal ring (4). The rubber bellows prevents leakage between the shaft (9) and rotating seal ring (4) and ensures axial flexibility despite contamination and deposits. In a rubber bellows seal, axial flexibility is obtained by elastic deformation of the bellows. In an O-ring seal, however, the O-ring slides along the shaft. The compression force from the spring keeps the two seal faces together during pump standstill and operation thanks to the flexibility of the bellows or O-ring. This flexibility also keeps the seal faces together, despite axial movements of the shaft, surface wear, and shaft run out.