Flexible Selection of Mechanical Seal Pump

Mechanical seal pump spindle axial and radial movement needs to maintain a certain degree of flexibility between the spring, in order to ensure the sealing between the contact surface. However, only a certain degree of flexibility can be provided. The mechanical condition of the mechanical seal pump and its length-diameter ratio (a measure of the diameter of the spindle and its extension length ratio, the lower the better ratio) play an important role in the reliability of the seal. The flexibility of the seal is generally guaranteed by a large main spring and a series of small spring or corrugated seals.

For traditional seal design, the sealing pressure is applied on the rotating surface, which is called rotary seal.  Because the spring or corrugated seal device rotates with the spindle. It is a relatively new design, because the spring or corrugated sealing device installed on the static surface. In the present mechanical seal pump seal, the above two sealing methods are very common applications, so for the installation of a certain degree of flexibility.

Early designs of many mechanical seal pumps used a single large spring arranged around the spindle. In the process of starting the liquid pump, it can provide strong sealing force for the sealing surface. The sealing action relies on the rotation of the spindle to tighten the spring coil.  Later design of mechanical seal pump uses a series of smaller springs, arranged around the spindle, which can produce a more uniform pressure load on the sealing surface. Since smaller springs can be installed beforehand, most of these seals are completely isolated from the liquid being pumped.

For many highly corrosive applications, the most common design is a metal bellows seal.  The bellows are a series of metal discs welded together to form a corrugated seal against leakage. This device can make the sealing pressure between the sealing surface more even, and there is no need to add a second seal on the sealing surface, so that no corrosion and wear will occur naturally.

In general, although the main sealing pressure depends on the pressure of the packing box itself, but the spring and bellows can compensate for the mechanical seal pump in the process of starting and stopping due to insufficient pressure of the spindle movement, so that the sealing surface always maintain a certain sealing pressure.