3
Installation, Operation and Maintenance Manual
MAN 564_EAC Rev. 2
June 2020
General Warnings
Section 1: General Warnings
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
Manual handpump
MHP (optional)
Control system
(optional)
Valve
coupling
Pneumatic
cylinder
Valve position
indicator
Scotch yoke
mechanism
Hydraulic cylinder for ALGA-MHP
models or second pneumatic
cylinder for ALGA*2 double
cylinder models (optional)
1.4
Data Sheet
Supply fluid
Air, nitrogen or sweet gas, special version available for sour gas
Operating temperature Standard: from –30 °C to +100 °C
Optional: from –60 °C to +200 °C
Supply pressure
Please refer to technical document: “actuator data-sheet”
Output torque
Up to 750000 Nm (higher value with special version)
