Product Description; General Product Description - Flowserve ROTADISK RD User Instructions

3

Product Description

General Product Description

3.1
The ROTADISK Pneumatic Actuators serve for valve automation. They are available in two
types:
▪
RD (double-action)
▪
RDF (single-action or spring-loaded return)
ROTADISK Pneumatic Actuators are based on a pneumatic twin piston drive according to
the Scotch-Yoke principle which are designed primarily for switching check valves and ball
valves. The twin piston drive is available in double-action and single-action versions.
With the smallest possible outer dimensions, the Scotch-Yoke principle enables a high torque
in the end positions.
The basic position in the standard design is CLOSED (NC: normally closed for single-action or
spring-loaded return RDF pneumatic actuators) and the standard direction of rotation,
looking onto the ROTADISK Pneumatic Actuator from above is clockwise (right-hand
rotation) for closing and anti-clockwise (left-hand rotation) for opening.
There is also an optional alternative design with standard OPEN position (NO: normally open
for single-action or spring-loaded return RDF pneumatic actuators). In this case, the
direction of rotation is anti-clockwise (left-hand rotation) for closing and clockwise (right-
hand rotation) for opening.
The tables below show the relation between design, type and piston position/transmission
shaft position:
Design
Basic position
Type
Piston
position/transmission shaft
position after
applied pressure/
venting
ROTADISK Pneumatic Actuator RD & RDF
standard
right-hand rotation (CW) or spring closing,
Normally Closed (NC) or Fail Close (FC)
CLOSED
RD double-action
transmission shaft position:
CLOSED
interior vented
exterior pressurised
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Operating Manual – BA3002 EN
3 Product Description
RDF single-action (spring
closing)
transmission shaft position:
CLOSED
interior vented