What is the difference between pneumatic and electric valves?

Pneumatic valves and electric valves are two common types of industrial valves, which have many differences in their working principles, performance characteristics, and application scenarios

Working principle

Pneumatic valve: Using compressed air as the power source, the pressure energy of compressed air is converted into mechanical energy through driving devices such as cylinders or membranes, thereby pushing the valve core to make reciprocating motion inside the valve body, achieving the opening and closing of the valve. When compressed air enters the cylinder or diaphragm chamber, pressure is generated on the valve core, causing it to move to the open or closed position; When compressed air is discharged, the valve core returns to its initial position under the action of reset devices such as springs.

Electric valve: Using an electric motor as a power source, the rotational motion of the motor is converted into linear or rotational motion of the valve core through transmission devices such as a reduction mechanism, thereby controlling the opening and closing of the valve. The forward and reverse rotation of the motor usually corresponds to the opening and closing operation of the valve, and its movement process can be precisely controlled by the control circuit.

Performance characteristics

Pneumatic Valve

advantage:

High safety: Pneumatic valves are relatively safe in hazardous environments such as flammable and explosive environments because their power source is compressed air, which does not generate electrical sparks and reduces the risk of fire or explosion.

High output force: capable of generating a large output force in a short period of time, suitable for controlling large-diameter or high-pressure pipeline media, can quickly and effectively overcome the pressure of pipeline media, and achieve valve opening and closing operations.

Simple structure: Its structure is relatively simple, mainly composed of components such as cylinder, valve core, valve seat, etc. It is relatively easy to maintain, easy to replace parts, and reduces maintenance costs and repair time.

Fast response speed: It responds quickly to control signals and can complete valve opening and closing actions in a short period of time. It is suitable for situations where rapid adjustment of medium flow or pressure is required.

Disadvantages:

Need for air source: A stable compressed air source must be equipped, which increases the complexity and cost of the system. If the gas supply is interrupted, the valve will not function properly.

Loud noise: During operation, the exhaust and other actions of the cylinder may produce loud noise, causing certain noise pollution to the working environment.

Relatively low control accuracy: Compared with electric valves, its control accuracy is relatively low, making it difficult to achieve very accurate flow or pressure control.

electric valve

advantage:

High control accuracy: Accurate control of valve opening can be achieved through precise motor control and feedback system, which can meet the high requirements for flow or pressure control accuracy.

No need for gas source: No additional gas source equipment is required, reducing the complexity and cost of the system. As long as there is a power supply, it can work normally and is more convenient to use.

Low noise: The noise generated during operation is relatively low, with minimal impact on the working environment, making it suitable for use in places with high noise requirements.

Remote control: Easy to integrate with automation control systems, valve opening and adjustment can be achieved through remote control signals, facilitating automation control and remote monitoring.

Disadvantages:

Slightly lower safety: There are certain safety hazards in flammable and explosive environments, as the motor may generate electric sparks and corresponding explosion-proof measures need to be taken.

Limited output force: Its output force is relatively small compared to pneumatic valves, and for large-diameter or high-pressure pipeline media, it may be necessary to use high-power motors, which increases costs and energy consumption.

Complex structure: The structure is relatively complex, including components such as motors, reduction mechanisms, and transmission devices, making maintenance relatively difficult. Once a malfunction occurs, the repair cost is high.

Application scenarios

Pneumatic valve: widely used in industries such as petrochemicals, natural gas, pharmaceuticals, food and beverage, especially suitable for situations that require fast switching, control of large flow or high-pressure media, such as emergency shutdown of natural gas pipelines, material transportation control in chemical production, etc. In some hazardous environments with extremely high safety requirements, such as oil depots and chemical plants in flammable and explosive areas, pneumatic valves are the preferred valve type.

Electric valve: commonly used in industries such as building water supply and drainage, HVAC, sewage treatment, and papermaking. It is suitable for situations that require high control accuracy, remote control, and automated operation, such as air conditioning water system control in building automation systems, and chemical dosing control in sewage treatment plants. Electric valves have also been widely used in some noise sensitive places, such as hospitals, schools, etc.

cost

Pneumatic valve: The equipment cost is relatively low, mainly the cost of components such as cylinders and valve bodies, but additional air source equipment such as air compressors is required, which increases the overall cost of the system. In terms of later maintenance, due to its simple structure, the maintenance cost is relatively low.

Electric valve: The equipment cost is relatively high, especially for components such as high-power motors and complex transmission mechanisms. However, it does not require additional gas source equipment, reducing the cost in this regard. In terms of maintenance costs, due to the complex structure, maintenance costs are relatively high, but with the development of technology and the intensification of market competition, their costs are gradually decreasing.