OLGAS-H
– High pressure spring return hydraulic actuator
Use and maintenance manual
© Copyright by BIFFI Italia. All right reserved.
Pag. 5
Contents may change without notice
1.2 IDENTIFICATION PLATE
It is forbidden to modify the information and the marks without
previous written authorization by BIFFI Italia S.r.l.
The plate fastened on the actuator contains the following information
(Figure1).
Figure 1
– Data plate
1.3 INTRODUCING THE ACTUATOR
The hydraulic actuator OLGAS-H was engineered and is
manufactured to provide fail safe operation 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 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 simplifies assembly. The spring action can
be easily changed in the field 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 flange 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 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
