Installation, Operation and Maintenance Manual
MAN 689 Rev. 6
June 2021
Figure 25
Scotch Yoke Mechanism Standard Version
Table 16.
Parts list
Item
Qty
Description
Material
1
4
O-ring
* NBR rubber
2
2
Yoke bushing
Bronze
3
2
Retainer ring
Stainless steel
4
1
Housing
Carbon steel
5
1
Guide bar
Alloy steel
6
1
Yoke
Carbon steel
7
1
Cover gasket
* SBR + Cel Fillers
8
1
Guide block
Carbon steel
9
1
Bushing
Steel + Teflon
10
2
Sliding block
Bronze
11
1
Vent valve
* Stainless steel
12
12
Screw
Carbon steel
13
1
Cover
Carbon steel
14
1
Guide block pin
Alloy steel
NOTE:
* Recommended spare parts
* Cycles perfromed by actuator in a 25 years expected lifetime - The minimum performed cycles
are guaranteed by Biffi based on service conditions listed:
- All the valve required torques have to be lower than actuator max operating torque (MOT)
- The ration between valve required running torque and actuator max operating torque (MOT) has
to be >1,5.
- The actuator mechanism has to be lubricated in accordance with indication given on this IOM.
45
Layouts and Sectional Drawings
Section 8: Layouts and Sectional Drawings
Section 8: Layouts and Sectional Drawings
7.1
Parts List for Maintenance and
Replacing Procedure