Analysis failure of mechanical seals

1, Mechanical Seal gear slipping. Some driving seat with the top wire fixed to the sleeve, and this transmission mode can still be used at room temperature, the temperature of the heat pump and centrifugal force, the top wire skid, transmission failure.
2, the stationary ring and the ring did not touch, installation of mechanical seal failure. Moving in the use of mosaic ring, tungsten carbide ring loose.
3, the friction face signs of wear soft ring width is greater than the friction of the two component sealing surface width are not equal. In general, the Muti Spring Mechanical Seals is wide, soft surface is narrow. Mechanical seal running for some time, the seal surface of a clear traces of friction, according to the width of this trace to determine the mechanical seal failure.
4, pump vibration, the mechanical seal ring operation produces radial and axial runout, the larger film thickness, and sometimes mechanical seals sealing surface is open, resulting in leakage increases. Movement rings a different mind. In general, the rotation type of seal, the stationary ring installed in the gland, the gland and seal when the coaxial cavity with the mouth by the only guarantee. In fact only the mouth is often the gap is too large, the stationary ring to sink, resulting in static rings of different hearts.
In the stationary bellows Johncrane Seal , due to the static weight of ring components contributed to sinking the static ring, ring movement also caused different heart. In addition, the bearing box of the gap is too large, so make the traces of friction shaft bending too broad. Ways to overcome these shortcomings, first remove the pump vibration, balancing the rotor to do; use are unlikely to cause vibration coupling; correct pump and motor concentricity; check the pump of the Mouth gap is too large; in the static bellows in the bottom ring to increase support in the static method to prevent sinking.
5, stationary ring seal faces the first phenomenon is the uneven sealing surface along the inner edge of the continuous exposure to traces of the so-called convergent gap: This seal, often can not find the dismantling of other signs of wear. Up and running
Leakage is large. Some people think that the friction traces of narrow, enclosed area is reduced, the pressure ratio increases, does not seem to be leaking. The opposite, when the inner edge of the contact, sealing the gap is to present the convergence of shape, damage to the sealing surface of the parallel film pressure increased significantly, pushing the sealing surface, leakage increases.
Ring face is not parallel to the static friction traces of the second sealing surface contacts the outer edge, which traces the internal diameter greater than the static friction ring seal surface diameter, sealing surface was horn-shaped, film pressure due to the shape of this gap decreases, resulting in than the pressure increases, the wear and tear, prone grooves, increasing the amount of leakage, can not function properly.
6, the Metal Bellow Seals ring side surface of the friction trace is not continuous or partial contact, sometimes circle or dot contacts, it is clearly caused by the uneven surface of the rotating ring. Solve the mechanical seals of these defects is: Check the dynamic and static ring of flatness, do not meet the requirements to carry out grinding until qualified. To reduce the deformation of the sealing surface, stationary ring seal interference value not too much, to avoid static ring deformation, high temperature
Secondary seal to take effective measures, such as washing, cooling, sealing itself to minimize the temperature difference.

Post time: Jun-25-2021