Mechanical seals needs drive mechanism because the torque is generated between the mechanical seal faces. The static drive is a task to hold an axial position and transmit torque. The dynamic drive is engaged in transmitting torque and allow for the axial flexibility of the primary seal ring. Dedicated devices made of strong materials are described to be positive drives and are generally preferred in the heavy duty mechanical seals.
Key drive is to keep the balance of the sturdy features incorporated in mechanical seals for high pressure applications.
Set screws are probably the most common type of static drive mechanism.They are not recommended for dynamic drive because the roughness of the threads can restrict axial flexibility of the primary seal rings
Pins include slotted pins, dowels or split roll pins.In the mating seal ring,they are probably one of the simplest methods of insurance to eliminate the possibility of spinning.
Snap ring drives are sometimes utilized when axial space limitations prevent the use of other types of drive.These are generally limited to light duty services without corrosion.
Slot is one of the best methods to ensure positive engagement between two parts that have relative axial motion between them.Its basic design also allows for the high degree of flexibility generally incorporated in the primary seal ring.
Elastomer Drive is not a positive drive method and is generally limited to light duty mechanical seals,it is extremely simple,economical and effective for some services.
Spring drive is another effective drive mechanism for light duty mechanical seals to incorporate the drive into the springs.Cautions must be taken in this design as to the direction of rotation,corrosion rate and spring rate.