Characteristics of Rubber Bellows Mechanical Seal

Bellows mechanical seal has a wide range of applications, from low temperature to high temperature, from neutral medium to corrosive medium, from low speed to high speed, from ordinary to harsh working conditions. Bellows includes rubber bellows, serpentine sleeve, plastic bellows and metal bellows. Rubber bellows and serpentine sleeve are used for low load mechanical seal as auxiliary seal; plastic bellows is used for strong corrosive medium mechanical seal as auxiliary seal.

The rubber bellows mechanical seal is the most commonly used bellows seal. Due to its compact design, it can be easily installed. It has a unique rubber bellows auxiliary seal, which can provide a high degree of axial flexibility to compensate for the concentricity of shaft misalignment wear caused by the thrust movement of the shaft. Since the drive torque is not transmitted by the coil spring, the seal can be used regardless of the direction of rotation. The required drive torque is increased by a unique rubber bellows mounted on the shaft. There are no bonded joints, all face materials are interchangeable, and there is no need to modify any dimensions.

Bellows is a kind of sealing element which integrates elastic element, auxiliary seal and torque transmission mechanism (ordinary seal does not have this kinetic energy), and its torque mode is unique to bellows mechanical seal. The specific pressure of the end face is uniform, which has the characteristics of high temperature resistance and good tracking performance. There is no auxiliary seal ring in the moving ring, so a leakage point is reduced, the friction resistance of the moving ring is reduced, and the following property of the moving ring is improved. There are two kinds of bellows commonly used: pressed and welded. The pressed bellows are made on the press or by hydraulic compression moulding by thin-walled tube elongation and forming. The welded bellows are made by welding the inner and outer circles of film sheets (commonly used).

Compared with the pressed bellows, the welded bellows has the following advantages: (1) due to its large radial stiffness and many kinds of materials, the range of pressure and temperature used in welded bellows is wide;

(2) the welded bellows can be used as spring with accurate working characteristics;

(3) the torsion stiffness is huge;

(4) The fatigue endurance limit is longer;

(5) The size is compact.