An actuator is a type of motor, typically operated by electric

current, hydraulic fluid or air pressure that's widely used in the

Process Industry for moving or controlling a mechanism or system.

How do actuators work?
Actuators take fluid, electric or some other source of power and

convert it through a motor, piston or other devices to perform work.

Basic versions are used to move

Actuated Valves

to either fully opened or fully closed positions. While

actuators for control or position regulating valves are given a

positioning signal to move to any intermediate position with a high

degree of accuracy.

Actuator types
There are four main types of actuators that are a combination of the

type of power applied and the type of movement required at the valve.

Pneumatic Actuators are one of the most common and

dependable configurations of actuators and are capable of quickly

operating very large valves. The main advantage of this type of

actuator is that all of the accessories are incorporated in the

package and are physically and environmentally protected. It has all

the basic and advanced functions incorporated in a compact housing

which can be watertight, explosion-proof and in some circumstances,


Electric Actuators are very similar except that the

final drive element is usually in one quadrant that puts out a 90°

motion. The newer generation of quarter-turn actuators incorporates

many of the features found in the most sophisticated multi-turn

actuators. They are compact, so can be used on smaller valves, and

because of their lower power requirements, they can be fitted with an

emergency power source such as a battery to provide failsafe


Fluid power quarter-turn actuators are extremely versatile and can

be used where there is no readily available electric power or where

simplicity and reliability are essential. They can also withstand

considerable mechanical abuse. The smallest can deliver a few inch

pounds of torque where the largest are capable of producing in excess

of a million inch-pounds of torque. Almost all fluid power actuators

utilize a cylinder and a mechanism to covert the linear motion

generated in the cylinder to a quarter-turn motion.

Fluid Power multi-turn actuators are frequently used when multi-

turn output is required to operate a linear type

Pneumatic Valves
(such as a gate or globe valve). Electric

actuators are often used for this type of valve but, if there is no

electric power supply readily available, pneumatic or hydraulic motors

can be used to operate multi-turn actuators.

Selecting a valve actuator
The correct type and size of

Valve Actuators

can be determined by checking:

The Power source
The type of valve
The torque required by the valve
Remote control

One of the great advantages of an automated valve is that it can be

remotely controlled without having to physically go to the

Electric Valves
and give it an open or close command. A common

method of positioning an actuator is to feed it a proportional signal

(such as 4-20 mA), so that the actuator can then position itself in

direct portion to the received signal.

If you have worked with any kind of fluid processing system, then you

are familiar with ball valves and the crucial job they do. Ball

Valves are quarter-

turn valves that are often made with full-bore designs. This means

they can completely stop flow when closed and will not hinder flow

when opened. This is valuable with flow rate and pressure are

important to the application. Stainless steel is one of the strongest

and most resilient materials out there, with top-notch pressure and

temperature resistances. There are too many applications for stainless

steel ball valves, but in this article we will look at some of the

most common. But first, what makes stainless steel so special?

What is Stainless Steel?
The reason there are so many uses for stainless steel

Ball Valves

is that it is a fantastic material. It is tougher than cast

iron, ductile iron, brass, and copper when it comes to pressure rating

and temperature tolerance. Stainless steel competes with carbon steel

on many fronts, but beats it by a mile in corrosion resistance. For

this reason, applications for stainless steel ball valves are

typically demanding in one or more area (corrosion, temperature,


Stainless steel is a fantastic material that is difficult to beat, but

it does have one major drawback: price. There is a major price jump

from iron valves to steel


, but it is warranted! The price jump is reflected by a

jump in quality from one material to another. Stainless steel is the

best of the best, with high pressure tolerance, temperature limits,

and corrosion resistance.