Application of multitrain electric actuators
Multi-turn electric actuators are primarily used in fluid transmission lines (water, oil, etc.) and on all types of valves, including ball valves, butterfly valves, gate valves, and needle (Globe Valve).
These electric actuators are typically installed on large valves (generally 6 inches and above), so an auxiliary gearbox is required to increase torque and increase the number of turns.
Butterfly valves, for example, require the input of the gearbox to rotate several times for the valve to completely open and close (by turning the tab 90 degrees). As a result of this method, multi-turn electric actuators can be used as electric valves.
Some valves, such as sliding and needle valves, require not only the rotation of the shaft to open and close, but also the up and down motion of the shaft. This type of valve requires a special gearbox to neutralize the up and down movement of the valve shaft.
The auxiliary gearboxes are chosen based on the size and type of valves, and the actuators are also chosen based on the gearboxes. Electric actuators are determined by the input torque, input revolutions, and input flange type of a gearbox.
A gearbox’s torque is determined by its type, size, and ratio of valves; A butterfly valve, for example, requires 1200 Nm of torque to open and close (turning the blade 90 degrees), but a 1 to 40 gearbox can reduce this to 30 Nm. Therefore, when the input shaft rotates 40 revolutions, the output shaft rotates 1 revolution, and since the output shaft of the gearbox rotates 90 degrees when the input shaft is rotated 10 revolutions, the valve opens and closes when the output shaft rotates 90 degrees.
Electric actuators for gearboxes are typically selected with a torque higher than the gearbox’s input torque (about 50%). The example above indicates that an actuator with about 50 newtons meters of torque should be considered.
The number of input revolutions of gearboxes is usually listed in catalogs. Gearbox catalogs specify the flange type according to ISO5211.
Multi-turn Electric Actuator Manufacturers
There are many countries and brands that produce multi-turn electric actuators. Here are some of the most popular electric actuators, each used in a different industry:
- Company AUMA The German company is a leading manufacturer of electric actuators and its products are used in almost every industry. Iran, however, uses electric actuators primarily for water and sewage industries, as well as oil and petrochemicals.
- ROTORK, an English company that manufactures electric actuators, is also one of the most important manufacturers of electric actuators.These actuators are usaully multi-turn electric actuators that are used widely in different industries. In Iran, this brand is more familiar to companies in the oil and petrochemical industries, and most of the electric actuators used in these industries come from this manufacturer.
- The BIFFI company in Italy is also one of the world’s largest producers of GAS OVER OIL actuators, which are familiar to oil and gas companies worldwide, including Iran.
- Siemens is also one of the oldest manufacturers of electric actuators in the world.