Installation, Operation and Maintenance Manual
MAN 608 Rev. 5 December 2020
General Warnings 3
Section 1: General Warnings
1.3 Introducing the Actuator
The hydraulic actuator OLGAS was engineered and is manufactured to provide fail safe
operation for any quarter turn application such as ball, plug, buttery valves or dampers, in
both On-Off and Modulating heavy duty service.
The actuator (see Figure 2) is made up of a weatherproof scotch yoke mechanism
transforming the linear movement of the hydraulic cylinder (on closing or opening) into
the rotary movement, which is necessary for operation. The spring module incorporates
up to four springs, fully encapsulated in a factory-welded cartridge: this ensure safety to
personnel and simplies assembly. The spring action can be easily changed in the eld
from “to close” in “to open” or vice- versa. The angular stroke of the yoke is adjustable
between 82° and 98° by means of the external mechanical stops screwed into the spring
cartridge and into the end ange of the hydraulic cylinder. The cover of the scotch yoke
mechanism is arranged for the assembly of the required accessories (positioner, signalling
limit switches, position transducer, etc.) by means of proper matching units. The above
mentioned accessories are operated by the actuator drive sleeve. The housing of the scotch
yoke mechanism has a ange with threaded holes to x the actuator to the valve either
directly or, if required, with the interposition of an adaptor ange or a mounting bracket.
The actuator yoke has a hole with keyways suitable for the assembly of an insert bush
the internal hole of which is machined (by Bif or at Customer's care), according to the
shape and dimensions of the valve stem. Bif can supply different types of control system
following Customer's requirements.
The expected lifetime of actuator is approximately 25 years .
1.4 Data Sheet
Supply uid Hydraulic oil, special versions for re-resistant uids
Operating temperature Standard: from –30 °C to +100 °C
Optional: from –60 °C to +140 °C
Design pressure 12 bar maximum
Supply pressure Please refer to technical document: “actuator data-sheet”
Figure 2 Identication of actuator parts
Spring cartridge
Valve position indicator
Hydraulic Cylinder
Valve Coupling
Scotch yoke
mechanism
