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Electrically driven valves are valves that use electric power as their driving mechanism. This type of driving device is commonly referred to as a valve actuator. The characteristics of valve actuators are as follows: 1) They can open and close quickly, thereby **reducing the time required to operate the valve； 2) It can **reduce the workload on operators, and is particularly suitable for high-pressure, large-diameter valves** ； 3) Suitable for installation in locations where manual operation is not possible or where access is difficult; it enables easy remote control, and there are no restrictions on the installation height ； 4) Conducive to the automation of the entire system ； 5) Power sources are easier to obtain than gas and liquid sources, and the installation and maintenance of their wires are also much simpler than those of compressed air and hydraulic pipelines. The disadvantage of valve actuators is their complex structure; they are more difficult to use in humid environments, and explosion-proof measures are required when used with explosive media. Valve actuators can be divided into two main categories, Z-type and Q-type, depending on the type of valve they drive. The output shaft of the Z-type valve actuator can rotate many times, making it suitable for driving gate valves, globe valves, diaphragm valves, etc ； The output shaft of the electric actuator for Q-type valves can only rotate 90 degrees. It is suitable for driving plug valves, ball valves, butterfly valves, etc. Based on their protection type, they include standard type, flameproof type (denoted by B), heat-resistant type (denoted by R), and three-in-one type (i.e., outdoor, corrosion-resistant, and flameproof, denoted by S). A valve actuator generally consists of a transmission mechanism (reducer), a motor, a travel control mechanism, a torque limitation mechanism, a manual-electric switching mechanism, an opening indicator, and so on. Pneumatic and hydraulic valves: Pneumatic and hydraulic valves use air, water, or oil under certain pressure as a power source, with the movement of cylinders (or hydraulic cylinders) and pistons being used to operate the valves. Generally, the air pressure in pneumatic systems is less than 0.8 MPa, while the water or oil pressure in hydraulic systems ranges from 2.5 MPa to 25 MPa. or diaphragm valve ； Rotary gas and liquid actuation devices are used to drive ball valves, butterfly valves, or plug valves. Hydraulic actuators have high driving force and are suitable for driving large-diameter valves. When used to drive plug valves, ball valves, and butterfly valves, the reciprocating motion of the piston must be converted into rotational motion. In addition to being driven by pistons in cylinders or hydraulic cylinders, there are also those driven by pneumatic diaphragms; due to their limited stroke and driving force, they are mainly used in control valves. Manual valve: A manual valve is a valve that uses the most basic type of actuation. It includes two types: direct drive using a handwheel, handle, or wrench, and drive through a transmission mechanism. When the starting torque of the valve is high, it can be driven via gear or worm gear transmission in order to eliminate this requirement. Gear drives are divided into straight cylindrical gear drives and bevel gear drives. Gear drives offer a low reduction ratio and are suitable for gate valves and globe valves, while worm gear drives provide a higher reduction ratio and are suitable for plug valves, ball valves, and butterfly valves.