The Wärtsilä Enviroguard MB and M4 (formerly Iceguard) are specifically fitted to military and commercial vessels, including container vessels and ice breakers. The unique omega shaped spring design absorbs all axial and radial movements from the shaft, ensuring the face carrier remains in contact with the seat assembly.
Wärtsilä Enviroguard MB is an inboard, closed water lubricated “omega” bellows, face type seal assembly. The Wärtsilä Enviroguard M4 is an outboard, closed water lubricated stern tube seal.
The seals features a rotating seat assembly and a stationary face carrier. Interface contact is maintained by spring pressure from the flexible bellows assembly. Through this seal design, the seal is able to accommodate large axial and radial movements, as well as high frequency vibration. The seal assembly is partially split, allowing wearing components to be replaced without removing the shaft. Emergency sealing features, such as a packing gland is also available.