December 2020
Installation, Operation and Maintenance Manual
MAN 606 Rev. 5
General Warnings
3
Section 1: General Warnings
1.3
Introducing the Actuator
The hydraulic actuator series OLGA was engineered and is manufactured to provide
maximum torque output with minimum supply pressure. The OLGA actuators is suitable
for any quarter turn application such as ball, plug, butterfly 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 pneumatic cylinder (on closing or opening) into
the rotary movement, which is necessary for operation. The angular stroke of the yoke is
adjustable between 82° and 98° by means of the external mechanical stops screwed into
the left wall of the mechanism housing and into the end flange of the pneumatic 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 flange with threaded holes
to fix the actuator to the valve either directly or, if required, with the interposition of an
adaptor flange 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 Biffi or at
Customer's care), according to the shape and dimensions of the valve stem. Biffi can supply
different types of control system following Customer's requirements.
The expected lifetime of actuator is approximately 25 years.
Figure 2
Identification of Actuator Parts
1.4
Data Sheet
Supply fluid
Hydraulic oil, special version for fire-resistant fluids
Operating temperature
Standard: from –30 °C to +100 °C
Optional: from –60 °C to +140 °C
Supply pressure
Please refer to technical document:
“actuator
data-sheet”
Hydraulic cylinder
Valve coupling
Scotch yoke mechanism
Optional: for OLGA MHP models or
second pneumatic cylinder for
“double cylinders” models
Manual handpump - MHP
(optional)
Valve position indicator
