Shut-down seal (cf. safety seal). The one common feature of all shut-down seals is that their sealing faces are not in contact during normal operation. They do not take over the sealing function until activated manually or automatically after the shaft is brought to a standstill. Shut-down seals are incorporated mainly as vessel locks in agitator seals. In terms of design, shut-down seals for compressors can be compared with a mechanical seal. Their modes of operation differ inasmuch as the sliding faces are separate during operation and are not closed by pressure of a buffer fluid system until the machine is shut down. When the buffer fluid pressure sinks, the seal is re-opened by spring forces.
Shut-down seals for compressors are usually made in combination with floating ring seals, including as safety seals.














Shut-down seal for a bottom drive, activated by lowering the shaft

Safety and shut-down seal for compressors. Pressure
build-up in cavity 1 moves the seal housing (2), the
mechanical seal closes and prevents product escaping
into the atmosphere


Pneumatic or hydraulic shut-down seal for lateral and
top drive