Flowserve ROTADISK RDF - Page 32

ROTADISK Pneumatic Actuator RD & RDF
Operating Manual – BA3002 EN
3 Product Description
Page 30 of 79
transmission shaft position:
OPEN
interior pressurised
exterior vented
transmission shaft position:
OPEN
interior pressurised
Design
alternative
left-hand rotation (CCW) or spring opening,
Normally Open (NO) or Fail Open (FO)
Basic position
OPEN
Type
RD double-action
RDF single-action (spring
opening)
Piston
position/transmission shaft
position after
pressure applied/
venting
transmission shaft position:
OPEN
interior vented
exterior pressurised
transmission shaft position:
OPEN
interior vented
exterior vented
transmission shaft position:
CLOSED
interior pressurised
exterior vented
transmission shaft position:
CLOSED
interior pressurised
exterior vented
ROTADISK Pneumatic Actuators have a fail-safe function. This function ensures that the
position is LOAD in the event of a compressed air drop in double-action ROTADISK
Pneumatic Actuators of the RD type. This means that the ROTADISK Pneumatic Actuator
stays in its last position in the event of a compressed air drop.
In single-action ROTADISK Pneumatic Actuators of the RDF type, the fail-safe function causes
the ROTADISK Pneumatic Actuator to move into the CLOSED position by means of the
springs (spring closing or Fail Close) in the event of a compressed air drop. Alternatively, it is