Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question from 2020-07-13
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Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question from 2020-07-13: Discussion question: 177. What are the characteristics of pneumatic long-stroke actuators?
It features a long stroke and high torque.
1. It accepts continuous pneumatic signals and outputs linear displacement (with an electric/pneumatic conversion device, it can also accept continuous electrical signals); when equipped with a rocker arm, it can output angular displacement. 2. It has positive and negative action functions. 3. It has a high moving speed, but the speed slows down when the load increases. 4. The output force is related to the operating pressure. 5. High reliability, but the valve cannot maintain its position in the event of a gas supply interruption (it can maintain its position if a position-retaining valve is used). 6. Segmented control and program control are difficult to implement. 7. It is simple to maintain and repair, and has good adaptability to the environment. 8. High output power. 9. It has explosion-proof functionality.
The characteristics of pneumatic actuators are as follows: 1. They receive continuous pneumatic signals and output linear displacement (with an electro-pneumatic conversion device, they can also receive continuous electrical signals); some models, when equipped with a rocker arm, can output angular displacement. 2. It has positive and negative action functions. 3. It has a high moving speed, but the speed slows down when the load increases. 4. The output force is related to the operating pressure. 5. High reliability, but the valve cannot maintain its position in the event of a gas supply interruption (it can maintain its position if a position-retaining valve is used). 6. Segmented control and program control are difficult to implement. 7. It is simple to maintain and repair, and has good adaptability to the environment. 8. High output power. 9. It has explosion-proof functionality.
Pneumatic long-stroke actuators are characterized by a long stroke and high torque; they convert air signals of 20–100 Kpa into corresponding angles (0–90°) or displacements (200–400 mm). They are suitable for use in angle-control valves, as well as in butterfly valves, gate valves (damper valves), etc., which require high torque.