1. Basic types of valve drivers
Depending on the driving method, valve drivers can be divided into the following types:
1. Electric Actuators
Electric actuators use motors to drive the opening and closing or adjustment of valves. Electric actuators are suitable for applications that require precise control of valve position, such as regulating valves, control valves, etc. The advantages of electric actuators are high control accuracy, fast response, and remote operation through control systems such as PLC.
- Advantages: High control accuracy, capable of precise switching and adjustment. Suitable for occasions requiring remote control and automation.
- Disadvantages: Suitable for small to medium-sized valves. For valves with large loads and high torques, a more powerful electric drive may be required.
2. Pneumatic Actuators
Pneumatic actuators use compressed air to drive the movement of valves and are usually used to switch valves. Pneumatic actuators have the advantages of fast response, high power, and reliable operation, and are widely used in factories and industrial environments with a high degree of automation.
- Advantages: Fast response speed, strong driving force, suitable for occasions that require frequent switching. Able to adapt to harsh environments and stable operation.
- Disadvantages: Requires air supply, relatively complex installation, and air system requires maintenance.
3. Hydraulic Actuators
Hydraulic actuators use the pressure of hydraulic oil to drive the opening and closing of valves. Hydraulic actuators are usually used in applications that require high torque and high force, such as large valves or high-pressure environments. Hydraulic actuators are commonly found in industries such as oil, natural gas, and electricity.
- Advantages: Can generate large driving force, suitable for applications with large torque and large loads.
- Disadvantages: It requires the support of hydraulic system, and the system is relatively complex and requires high maintenance.
4. Manual Actuators
Manual actuators are controlled by operators directly through mechanical means to open and close the valve. Common manual actuators include gear handwheels, worm gears, etc., which are usually used for smaller valves or occasions where automatic control is not required.
- Advantages: Simple structure, low price, suitable for occasions where automatic control is not required.
- Disadvantages: Manual operation is required, not suitable for large-scale automatic control systems, and the efficiency is low.
5. Smart Actuators
Smart actuators are drive devices that combine electric or pneumatic actuators with intelligent control technology, with functions such as self-diagnosis, remote monitoring and intelligent adjustment. It can be monitored and adjusted in real time through sensors and control systems, and is suitable for industrial environments that require high precision and high automation.
- Advantages: Highly automated, able to monitor and adjust valve position in real time, and adapt to complex working conditions.
- Disadvantages: High price and high technical requirements.
2. Key factors in choosing valve actuators
When choosing valve actuators, you need to choose the most suitable drive mode and model based on the following key factors:
1. Valve type and size
The choice of actuator is closely related to the type, size and working pressure of the valve. For example, large valves or high-pressure valves may require more powerful actuators, and pneumatic or hydraulic actuators are usually selected.
- Small valves: Electric actuators can usually meet the needs, respond accurately and save energy.
- Large valves or high torque requirements: Hydraulic or pneumatic actuators can provide greater torque.
2. Control accuracy requirements
If the system requires precise valve position adjustment or flow control, electric actuators are the most suitable choice. Electric actuators can cooperate with control systems (such as PLC, DCS) to provide precise feedback adjustment, and are suitable for fine control occasions such as regulating valves and control valves.
3. Working environment
The working environment of the actuator (such as temperature, humidity, whether there are corrosive gases, etc.) will affect the choice of actuator. For applications in high temperature, high pressure and corrosive environments, hydraulic actuators and pneumatic actuators are usually more advantageous.
- High temperature or harsh environment: Choose a pneumatic or hydraulic drive that is resistant to high temperature and corrosion.
- Clean and clean environment: Electric drives are suitable, especially in precision factories and laboratory environments.
4. Response speed
For some occasions that require fast response, pneumatic drives are usually the best choice. Pneumatic drives are suitable for frequent starts and stops or fast control due to their fast response speed of air compression.
- Fast response: Pneumatic drives.
- Slow adjustment: Electric drives are more suitable for applications that require precise adjustment and progressive control.
5. Power requirement
Choose a drive with appropriate power according to the size, weight and operating requirements of the valve. The power requirement of electric drives is usually determined by voltage, power and valve type, while the power requirement of pneumatic and hydraulic drives is usually related to the pressure and flow of the air source or hydraulic system.
- Low power requirement: Suitable for electric drives.
- High power requirement: Hydraulic drives or pneumatic drives.
6. Operation and maintenance requirements
When selecting a drive, in addition to considering its performance, you also need to consider the subsequent operation and maintenance requirements. Some types of actuators (such as electric actuators) can be integrated with intelligent control systems to achieve remote control and monitoring, reducing manual operation and maintenance costs.
- Easy to operate: Manual actuators are suitable for smaller valves and do not require electrical support.
- Automated control: Electric or pneumatic actuators are suitable for large-scale automated systems and support remote operation and intelligent control.
7. Safety
The actuator needs to have sufficient safety, especially under special working conditions such as high pressure, flammable and explosive. Pneumatic and hydraulic actuators are generally more suitable for high-pressure applications, but their safety and protection level also need to be ensured.
3. Common application areas
1. Chemical and oil and gas industries
In the chemical and oil and gas industries, actuators are used to control various valves, such as ball valves, butterfly valves, and regulating valves. Pneumatic and hydraulic actuators are often used in high-pressure, high-temperature, and corrosive gas environments.
2. Power industry
In the power industry, actuators are used for valve control of equipment such as boilers and cooling systems. Electric actuators and pneumatic actuators are often used in these applications, and electric actuators help to accurately control flow and pressure.
3. Water treatment and sewage treatment
In water treatment and sewage treatment systems, the driver is used to control the opening and closing of the water inlet and outlet valves to ensure the regulation of water flow and pressure. Both electric and pneumatic drivers can meet this demand.
4. Food and pharmaceutical industry
In the food and pharmaceutical industry, the driver is used to control precision valves to ensure the stability of flow and pressure. Especially in environments with high hygiene and cleanliness requirements, electric drivers have significant advantages.
5. HVAC system
In the heating, ventilation and air conditioning (HVAC) system, the driver is used to control air flow and temperature regulation. Electric drivers are usually used in such occasions with high precision regulation requirements.
4. Selection case
Suppose a manufacturer needs to purchase a driver for the pipeline control system in its chemical production line. Considering the working environment and operating requirements of the system, the selection can be based on the following criteria:
- Valve type and size: The valves used in this chemical production line are large and require high pressure, good sealing, and frequent opening and closing. Therefore, pneumatic or hydraulic drivers can be selected. Both drivers can provide strong torque and are suitable for large flow and high pressure systems.
- Control accuracy: For the precise adjustment of some control valves, electric drives may be more suitable. Electric drives adjust the opening and closing degree of valves through precise control signals, thereby adjusting fluid flow and temperature. Therefore, in precise adjustment occasions, electric drives can provide higher control accuracy.
- Working environment: Chemical plants usually involve harsh working environments such as high temperature and corrosive gases, so the materials and designs of the selected drives need to be resistant to high temperature and corrosion. Hydraulic drives and pneumatic drives are usually better adapted to this environment, while electric drives need to be selected with high temperature resistance and explosion-proof design models.
- Operation and maintenance requirements: Considering the automation control requirements of the chemical plant, the selection of pneumatic drives or electric drives can meet the needs of automation control. In addition, the convenience of equipment maintenance should be considered when selecting. It is recommended to select intelligent drives with self-diagnosis and remote monitoring functions, which can reduce manual intervention and improve operation and maintenance efficiency.
- Power and energy efficiency: Since the plant involves a large number of automated operations, pneumatic drives may be the best choice. Pneumatic actuators can provide strong driving force through compressed air, which is suitable for frequent switching and high torque requirements, and will not consume too much electricity like electric actuators.
- Safety: Considering the special environment of chemical plants, the safety of the actuator is a very important selection factor. Pneumatic and hydraulic actuators have natural advantages in explosion-proof and safety performance, especially in the environment of flammable and explosive gases, which can be ensured by explosion-proof design.
Based on these considerations, the combination of pneumatic actuator and electric actuator was finally selected. Pneumatic actuators are used for the control of conventional switch valves and large flow control valves, while electric actuators are used for regulating valves that require precise adjustment and remote control.
5. Summary
When purchasing a suitable valve actuator, it is necessary to consider a variety of factors such as valve type, working environment, control accuracy requirements, power requirements, operation and maintenance, and safety. Different types of actuators have their own advantages. Pneumatic actuators are suitable for high response speed and high torque applications, hydraulic actuators are suitable for high load applications, electric actuators are suitable for occasions requiring precise control, and intelligent actuators provide convenience for automation and remote monitoring.
Through reasonable selection, the efficiency, safety and reliability of the valve control system can be improved, the production process can be optimized, maintenance costs can be reduced, and the long-term stable operation of the equipment can be ensured. Therefore, choosing the right driver is crucial to ensure the efficient operation of the production line.