|Actuators are used for the automation of industrial valves and can be used in all kinds of technical process plants such as wastewater treatment plants, power plants and even refineries. The valves to be automated vary both in design and dimension. The diameters of the valves range from a few inches to a few meters.
Multi-turn actuators are required for the automation of multi-turn valves. One of the major representatives of this type is the gate valve. "A multi-turn actuator is an actuator which transmits to the valve a torque for at least one full revolution. It is capable of withstanding thrust."
Part-turn actuators are required for the automation of part-turn valves. Major representatives of this type are butterfly valves and ball valves. "A part-turn actuator is an actuator which transmits a torque to the valve for less than one full revolution. It need not be capable of withstanding thrust."
Currently there is no international standard describing linear actuators or linear thrust units. A typical representative of the valves to be automated is the control valve. Just like the plug in the bathtub is pressed into the drain, the plug is pressed into the plug seat by a stroke movement. The pressure of the medium acts upon the plug while the thrust unit has to provide the same amount of thrust to be able to hold and move the plug against this pressure. Most of the linear actuators used are pneumatic diaphragm actuators. They are characterized by a simple design principle and are therefore cost-effective. A compressed air supply is a prerequisite for their use. In case this is not possible, the use of thrust units is recommended which can easily be supplied with power.
Small electric actuators can be used in a wide variety of assembly, packaging and testing applications. Such actuators can be linear, rotary, or a combination of the two, and can be combined to perform work in three dimensions. Such actuators are often used to replace pneumatic cylinders.