Development and Application of Mechanical Seals in Industry

1. The technology development of mechanical seals

Rubber is the most commonly used sealing material. In addition to rubber, graphite, polytetrafluoroethylene and various sealants are also suitable for sealing materials.

At present, the new technologies of various mechanical seals adopting new materials and processes have made rapid progress. In recent years, the slotted seal technology of seal face has opened a variety of flow grooves on the single cartridge of mechanical seals to produce hydrostatic and dynamic pressure effects, which are still being updated.

In the past, zero leakage seal technology always believed that contact and non-contact mechanical seals could not achieve zero leakage (or no leakage). Israel uses slotted seal technology to put forward a new concept of zero leakage non-contact mechanical face seal, which has been used in lubricating oil pump of nuclear power plant. Dry running gas seal technology uses slotted seal technology for gas seal. The upstream pumping sealing technology is to pump a small amount of leakage fluid from the downstream back to the upstream by using a flow groove on the sealing surface.

2. The structural characteristics of the above-mentioned mechanical seals:

Shallow groove is adopted, the film thickness and the depth of the launder are both micron level, lubrication groove, radial sealing dam and circumferential sealing weir are used to form the sealing and bearing part. It can also be said that slotted seal is the combination of plane seal and slotted bearing.

Its advantages are small leakage (even no leakage), large film thickness, elimination of contact friction, low power consumption and heat generation. The technology of thermal fluid dynamic pressure seal is to make use of all kinds of deep groove of sealing surface to cause local thermal deformation and produce hydrodynamic wedge effect. This kind of seal with hydrodynamic bearing capacity is called thermo hydrodynamic wedge seal.

The technology of metal bellows mechanical seal can be divided into the forming metal bellows and the welding metal bellows mechanical sealing technology.

Multi face seal technology is divided into double seal, intermediate ring seal and multi seal technology. In addition, there are parallel sealing technology, monitoring sealing technology, combined sealing technology and so on.