Hermetic Seals - magnetic coupling

Because hermetic drives are usually used for applications with stringent safety requirements, EKATO's ESM agitators are built with buffer-fluid-lubricated bearings.

This version necessitates sealing against the product space. A single-acting mechanical seal with ceramic seal rings performs this duty. The bearing cavity created by the seal, referred to as the buffer chamber, can be filled with a fluid suitable for bearing lubrication.

A pressure booster VDH controls the buffer liquid pressure in such a way that the isolating seal is always operated with an optimal pressure difference.

The arrangement depicted in Fig. 13, with isolating mechanical seal and can, offers substantial safety advantages. First, the isolating seal prevents the harmful substances from escaping to the surroundings in the event of damage to the hermetic seal. Second, the pressure gradient towards the product space ensures that, in the event of leakage at the isolating seal, the buffer fluid will flow toward the vessel side rather than contaminating the buffer chamber. This protects crucial functional components, namely the can, inner magnet, and bearing.

Another advantage of this design is the ability to check for leakage at a glance at the buffer fluid gauge on the pressure booster. By comparison, leakage checking with a gas-lubricated bearing necessitates the use of a costly double-walled can.

To meet specific needs, the following monitoring devices are available:

• rotary speed monitor
• leakage monitor using switch contacts on the pressure compensator
• temperature monitor on the can
• cooling water controller for keeping the optimal flow rate constant
• soft start module for reducing the motor's starting and/or breakdown torque.