Installation, Operation and Maintenance Manual
MAN 601 Rev. 7 December 2020
General Warnings 3
Section 1: General Warnings
1.3 Introducing the Actuator
The direct gas actuator GIG 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 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 ange 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 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 .
Supply uid Sweet, dry natural gas; sour high pressure gas; nitrogen or
instrument air
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”
Figure 2 Identication of actuator parts
Manual handpump
MHP (optional)
Pneumatic cylinder
Valve position indicator
Valve Coupling
Scotch yoke
mechanism
1.4 Data Sheet
Hydraulic Cylinder
for GIG-MHP models or
second pneumatic cylinder
for “twin gas cylinder”
models (optional)
