A Comparative Analysis of the Advantages and Disadvantages of Pneumatic and Electric Valves
The operating principle of pneumatic valves relies on compressed air to drive multiple sets of combined pneumatic pistons within the actuator. This motion is transmitted via a crossbeam and an internal curved track to rotate the hollow main shaft. Compressed air is distributed to individual cylinders through an air distribution manifold, with the rotational direction of the main shaft controlled by altering the inlet and exhaust ports. Depending on the required torque for the valve load, the number of cylinder assemblies can be adjusted accordingly to drive the valve into operation. A two-position five-way solenoid valve is typically used in conjunction with a double-acting pneumatic actuator. This valve has two controllable positions—open and closed—and five air channels: one connected to the air supply source, two linked to the external chamber’s air inlet and outlet ports of the double-acting cylinder, and two connected to the internal chamber’s corresponding ports. For detailed operational mechanisms, reference can be made to the working principles of double-acting pneumatic actuators. With the advancement of control technologies and methodologies, pneumatic actuators are now employed through various control strategies in industrial production and automation systems.
1. Reliability: It is commonly believed that pneumatic valves exhibit higher reliability compared to electric valves, which have historically been considered less reliable. However, electric valve actuators incorporate advanced integrated circuit technology, overcoming previous design limitations. These modern actuators now achieve an average service life of 5 to 10 years, meeting or even exceeding that of pneumatic valves. Therefore, in terms of reliability, both types demonstrate comparable performance, each with distinct strengths under specific conditions.
2. Application in High-Explosion-Risk Environments: In industrial settings where intrinsic safety and explosion protection are critical, pneumatic actuators are predominantly preferred. A key advantage of pneumatic valves lies in their inherent safety and natural explosion-proof characteristics. However, this benefit comes with a significant drawback—the necessity of establishing a complete pneumatic infrastructure (e.g., air compressors, piping networks), which increases initial setup costs. In contrast, electric valve actuators can utilize locally available power sources. When explosion risks are moderate and compressed air supply is impractical, electric valves become the more viable and convenient option.
3. Cost Comparison: The technical specifications of electric valve actuators are generally equivalent to those of pneumatic actuators paired with positioners, regardless of whether the products are domestically manufactured or imported. However, due to the additional requirement for auxiliary equipment such as air compressor stations and distribution systems, pneumatic valve installations incur higher overall system costs. Consequently, electric valves offer a cost advantage in many applications.
4. Actuator Selection Based on Output Requirements: The choice of actuator with sufficient output capacity depends on the valve type and the permissible pressure differential across the valve. Therefore, the selection and matching process must be tailored to specific application requirements and should be approached with flexibility and engineering judgment.
5. Fire and Explosion Safety: In hazardous environments involving flammable or explosive materials, pneumatic actuators—especially when combined with positioners—demonstrate superior safety performance compared to electric actuators. First, only a limited number of electric actuators are available in certified explosion-proof configurations. Second, electric actuators are generally prohibited in highly sensitive areas due to the risk of spark generation and thermal effects. Thus, from a fire and explosion prevention standpoint, pneumatic solutions remain the preferred choice in such high-risk applications.