HYDRAULIC & ELECTRIC VALVE ACTUATORS

Hydraulic actuators: 

1. —  Construction is similar to Cylinder type actuators.
2. —  Pressurized oil is used for operation.
3. —  Used for valves when force required is high.

ELECTRICAL ACTUATORS:  

They are Electro-mechanical devices used for operating valves. They consist of an assembly of a motor, a gear box and its controls.

They can be classified into two types:

1. Rotary

2. Linear

Rotary actuators: 

1. —  They are actuators having a rotating output shaft.
2. —  They are commonly used as they do not have any limitation with respect to valve travel.
3. —  Their use is widespread.

Linear actuators:

•      They are actuators having a reciprocating output shaft.

•      They have a limitation with respect to stroke length (valve travel).

•      Their use is limited.