What is a Valve Actuator?
The valve actuator is used to receive the control signal sent by the controller so that the size and amount of the controlled medium will be changed at the same time the controlled variable can be maintained within the required range. Valve actuators play a very important role in automatic control systems. It is mainly a device that uses power to operate the valve. When the actuator gains power, it will produce a specific movement according to the received control signal. The form of its energy can be divided into three categories: pneumatic, hydraulic and electric. Below we will analyze the characteristics and uses of these three types of valve actuators.
The main purposes of valve actuators are as follows:
1. The valve actuator can be used in some closure mechanisms, such as balls or plugs.
2. It can be used to keep and remain the valve closed.
3. By rotating 90 or 180 degrees, the valve can be opened or closed.
Generally, actuators can be divided into two types of valve movement, namely rotary movement and linear movement.
Rotary valve actuator
Rotary valve actuators are mainly used to operate rotary valves that need to be rotated, such as ball valves and butterfly valves. Most rotary valve actuators are electric, while a few use hydraulic and pneumatic forms to provide power. The rotary valve actuator creates a circular motion, which uses rotation to complete the rotary motion of the machine.
Linear valve actuator
A linear valve actuator is an actuator that generates linear motion in a straight path to operate the valve. Mainly used for hydraulic and pneumatic mechanical equipment. Used in linear valves that move linearly, such as gate valves, and stop valves. The linear valve actuator has three parts: a sliding tube, a nut and a cover. Their function is mainly to help the actuator to maintain the linear direction of movement.
Power Source
The power source used for the movement of the rotary valve actuator and the linear valve actuator can be divided into the hydraulic actuator, pneumatic actuator, and electric actuator.
Hydraulic actuator
The hydraulic actuator is mainly used in a cylinder filled with fluid to control the movement of the valve by means of pressurizing the fluid. The fluid is mainly liquid such as water or oil, which is operated by hydraulic pressure to transport the fluid to one side of the piston, thereby generating a movement. Usually, one end of the hydraulic actuator will be connected to the spring to make repeated reciprocating movements, mainly to produce linear movement. Most of these hydraulic actuators are used in the oil refining industry, chemical industry, and some sports equipment. The hydraulic actuator can accurately control the valve and can convert a small input pressure into a large output pressure. However, hydraulic actuators also have some shortcomings. For example, its working efficiency will be affected by the weather, and the price is relatively expensive. It is not suitable for use in places prone to fire hazards, because this type of actuator has the risk of leakage.
Pneumatic actuators
Pneumatic actuators are characterized by the use of compressed air. Pressurized with gas as an energy source to generate power and operate valves. This type of actuator mainly controls the valve by connecting the force of compressed air to the diaphragm of the valve stem or the piston. Pneumatic actuators can move very accurately when starting and suspending machinery and equipment. Its simple structure, high reliability, stability, low price, low fire risk, convenient maintenance, and it can be used in the case of power failure, all of these advantages make it widely used in all industries. Pneumatic actuators are mostly used in production industries such as oil refineries, chemical industry, paper industry, and other industries. However, the performance of pneumatic actuators may not be very good at low speeds. Also, when the air is compressed, it will also cause the shaft to move at different speeds.
Electric actuators
Electric actuators are actuators that rely on electricity to operate. It can convert the signal quickly into linear motion or rotary motion for transmission. Electric actuators include solenoid valves and motors. Solenoid valves mainly use electricity to adsorb the magnetic core on the valve stem for automatic valve applications. The structure of the electric actuator is complex and expensive, which is likely to cause fire and power outage problems. However, it does not require compressed fluid to generate power, so it’s very suitable for use in low-temperature environments and can produce consistent operating speeds. Electric actuators often move on electric vehicles and robotic equipment.
Contact MecHero at 011-7000 7687 or my.mechero@gmail.com right now to get your valve actuator.