Dry Gas Seals Use two planes to rub against each other
The basic elements of dry gas seal
Mechanical dry gas seal is the use of two plane friction with each other to run the principle of dry gas to achieve the purpose of sealing. The rotary dry gas seal is mounted on the main shaft of the pump and the fixed dry gas seal is mounted in the dry gas seal gland. Since a dry gas seal is moving and the other dry gas seal is stationary, this dry gas seal is referred to as a dynamic dry gas seal.
The latter two leaks are generally static dry gas seals because there is no relative movement between the two parts. This part of the dry gas seal is usually referred to as a three dry gas seal, the dry gas sealing material for the gasket or the process of liquid to adapt to the O-type dry gas seal.
In the older dry gas seal design, the secondary dry gas seal located under the rotating surface leaves a certain gap that can move back and forth on the spindle, making it easy to cause wear and premature failure. However, in the newer dry gas seal design, the secondary dry gas seal is at rest, thus avoiding wear and tear on the spindle.
In the normal operation of the liquid pump, the rotation surface and the stationary surface are kept in the dry gas sealed state by the pressure generated by the liquid in the packing box. At the time of starting and stopping, the pressure of the packing box is caused by the pressure To maintain (even by the pressure of the spring instead).
Most mechanical dry gas seals are designed with a softer material to produce a rotating surface that rotates friction on a harder stationary surface. Over the years, the most common combination is the use of carbon material as a rotating surface, so that it works on the ceramic stationary surface. Such materials are still widely used, but the static surface is made of stainless steel or harder materials, such as tungsten carbide or silicon carbide.
No matter what material, in short, between the contact surface must maintain a layer of liquid film to play a role in lubrication. However, in the box, the use of spring load and liquid pressure combined with the way, can make dry gas seal between the surface to play a good dry gas seal. But dry gas seal pressure is too high, it will affect the formation of liquid film between the contact surface, resulting in increased heat and premature wear. If the dry gas seal pressure is too low, the gap between the contact surface increases, likely to cause liquid leakage.
Dry gas sealing factories are constantly working to improve the flatness of the contact surface, they use a special polishing plate for grinding. Then, the monochromatic light source of the grating plate to its detection. From this point of view, it is important that these dry gas contact surfaces be handled with care and that the dry seal is properly protected and properly seated in accordance with the installation instructions.