Actuators are critical components in the automation and control of industrial valves. They are responsible for converting a signal, typically electrical or pneumatic, into mechanical motion, which moves the valve to the desired position. Multi-turn and quarter-turn actuators are two common actuators used in industrial applications. This article explains the differences between these two types of actuators and their use cases in valve automation.
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Multi-Turn Actuators
Multi-turn actuators are used to operate valves that require multiple rotations to operate fully. The number of rotations required depends on the valve’s design and the required flow rate. Multi-turn actuators can be classified into two categories: electric and pneumatic.
Electric multi-turn actuators use a motor to convert the input signal into rotary motion. The motor is connected to a gearbox, which converts the rotary motion into linear motion. The linear motion is then used to operate the valve. Electric multi-turn actuators are typically used in applications where a high degree of accuracy and repeatability is required.
Pneumatic multi-turn actuators use compressed air to convert the input signal into rotary motion. Compressed air is used to actuate a piston or a diaphragm connected to a gearbox. The gearbox converts the linear motion into rotary motion, which is then used to operate the valve. Pneumatic multi-turn actuators are typically used in applications requiring a high degree of force.
Multi-turn actuators are commonly used in gate, globe, and butterfly valves. They are also used in high-precision applications, such as water treatment plants, oil refineries, and chemical processing plants.
Quarter-Turn Actuators (Part Turn)
Quarter-turn (part-turn) actuators are used to operate valves that require a rotational motion of 90 degrees or less to operate fully. Depending on the valve’s design, the motion can be either clockwise or counterclockwise. Quarter-turn actuators can be classified into two categories: rotary and linear.
Rotary quarter-turn actuators convert the input signal into rotary motion to operate the valve. The rotary motion can be either direct or indirect, depending on the actuator’s design. Direct rotary quarter-turn actuators have a shaft directly connected to the valve stem. As the actuator rotates, it directly rotates the valve stem, opening or closing it. Indirect rotary quarter-turn actuators use a mechanism, such as a gearbox or a scotch yoke mechanism, to convert the input signal into rotary motion. The rotary motion is then transmitted to the valve stem, which opens or closes the valve.
Linear quarter-turn actuators convert the input signal into linear motion, which is then converted into rotary motion to operate the valve. The linear motion can be achieved using a piston or a diaphragm, which is actuated by the input signal. The linear motion is then converted into rotary motion by using a mechanism, such as a rack and a pinion, to operate the valve.
Quarter-turn actuators are typically used in applications requiring a fast response time and high repeatability. They are commonly used in ball, butterfly, and plug valves. They are also used in applications with limited space or the valve is located in hard-to-reach areas.
What is the difference between quarter-turn and multi-turn actuators?
Multi-turn actuators are used to operate valves that require multiple rotations to operate fully. The number of rotations required depends on the valve’s design and the required flow rate. Multi-turn actuators can be classified into two categories: electric and pneumatic.
Electric multi-turn actuators use a motor to convert the input signal into rotary motion. The motor is connected to a gearbox, which converts the rotary motion into linear motion. The linear motion is then used to operate the valve. Electric multi-turn actuators are typically used in applications where a high degree of accuracy and repeatability is required.
Pneumatic multi-turn actuators use compressed air to convert the input signal into rotary motion. Compressed air is used to actuate a piston or a diaphragm connected to a gearbox. The gearbox converts the linear motion into rotary motion, which is then used to operate the valve. Pneumatic multi-turn actuators are typically used in applications requiring a high degree of force.
Multi-turn actuators are commonly used in gate, globe, and butterfly valves. They are also used in high-precision applications, such as water treatment plants, oil refineries, and chemical processing plants.
Required Linear Motion
The primary difference between quarter-turn and multi-turn actuators is the amount of rotary or linear motion required to operate the valve. Quarter-turn actuators require a rotational motion of 90 degrees or less to operate fully. In contrast, multi-turn actuators require multiple rotations to operate fully. This means that multi-turn actuators are typically slower than quarter-turn actuators. Still, they can provide a higher degree of accuracy and repeatability.
Valve Types
Another difference between quarter-turn and multi-turn actuators is the type of valve they are used to operate. Quarter-turn actuators are typically used in ball, butterfly, and plug valves. In contrast, multi-turn actuators are commonly used in gate, globe, and sluice valves. This is because the design of these valves requires multiple rotations to operate fully, and they are typically used in applications where a high degree of precision and accuracy is required.
Dimensions
Quarter-turn actuators are also typically smaller and more compact than multi-turn actuators. This makes them ideal for applications where space is limited, or the valve is located in hard-to-reach areas. On the other hand, multi-turn actuators are typically larger and more powerful, making them ideal for applications requiring a high degree of force.
Conclusion On Multi-Turn vs Quarter-Turn Actuators
In conclusion, the type of actuator used in a particular application depends on various factors, including the type of valve, the required flow rate, the operating environment, and the available power source. Both quarter-turn and multi-turn actuators have advantages and disadvantages. The choice will depend on the application’s specific requirements.
Quarter-turn and multi-turn actuators are two common types of actuators used in industrial applications. Quarter-turn actuators operate valves that require a rotational motion of 90 degrees or less. In contrast, multi-turn actuators operate valves that require multiple rotations to operate fully. Both types of actuators have their advantages and disadvantages, and the choice between them will depend on the application’s specific requirements. When selecting an actuator for a particular application, it is important to carefully consider the type of valve, the required flow rate, the operating environment, and the available power source.