Difference between pneumatic and electric butterfly valves
Pneumatic butterfly valve
Butterfly valve with pneumatic actuator to drive the valve switch, powered by compressed air, has the characteristics of simple structure, more convenient maintenance, etc., but large volume, need air source and air purification device; pneumatic actuator actuator and adjustment mechanism is a unified whole, its actuator has film type, piston type, toggle type and rack and pinion type.
Advantages of pneumatic butterfly valve: good effect on small and medium diameter liquid of gas, low cost, easy maintenance.
Disadvantages: affected by fluctuations in air pressure, in the northern winter is susceptible to the influence of air pressure containing water, resulting in the transmission part of the freezing and can not operate.
Electric butterfly valve
Butterfly valves with electric actuators to drive the valve on and off, are powered by electricity, using single-phase or three-phase motors to drive gears or worm gears to output linear or rotary motion. The electric actuator can output a relatively constant driving force, with strong resistance to deviation and higher control accuracy than the pneumatic actuator, and can automatically hold the position without the help of other auxiliary systems.
Electric actuators are easy to operate, easy to achieve remote control and other characteristics, but their structure is complex and prone to failure, often low positioning accuracy, over-opening and closing, motor burnout, gear box wear, etc., maintenance costs are large. Too frequent adjustment will cause the motor to heat up and the reduction gear to wear out. In addition, the electric actuator runs slowly, making it difficult to achieve large driving forces, and there are problems such as difficulties in achieving over-protection and poor position.
Advantages of electric butterfly valves: good effect on liquid media and large diameter gases, not affected by climate and air pressure.
Disadvantages: high cost, bad for humid environments.
- In terms of cost, pneumatic actuators are relatively inexpensive, while electric actuators are relatively expensive
- Some larger diameter pipelines or places that do not need explosion-proof use electric butterfly valves, because pneumatic movement is difficult to achieve, but the stability of electric valves is not as good as pneumatic, switching speed is slow, and the actuator will be stuck for a long time. Pneumatic butterfly valves are generally used for small diameter pipelines, which are not only light in weight but also small in size and easy to maintain at a later stage. However, the requirements for the air source are particularly high.
|Pneumatic actuator||Electric actuator|
|Medium of pipes||Liquid in small diameter pipe & gas||Gas in large diameter pipes & liquid|
|Control system||More complex with multiple accessories||Integral|
|Environment factor||If air source contains the water, the driving system will fail||Not suitable in damp environment|
|Safety & reliability||Higher, and also need stable air supply||Less higher, sometimes there occurs jam|
In summary, electric butterfly valves and pneumatic butterfly valves each have unique characteristics, different situations have different control needs, can not simply judge the end which is good to use, the key to combine the actual application conditions, production requirements to decide which one to choose. If you have any questions regarding the selection of butterfly valves, you can contact VALTECCN’s customer service staff.