Views: 226 Author: Site Editor Publish Time: 2021-04-21 Origin: Site
An electric motor actuator is a driving device that can provide linear or rotational motion. It uses a certain driving energy and works under certain control signals. The actuator uses liquid, gas, electricity or other energy and converts it into a driving function through a motor, electric pneumatic cylinder or other devices.
The commonly used electric valve actuators are divided into 3 categories, small type, Q type and Z type.
It is characterized by small size, minimum space occupation, low cost, and no need to add a hand wheel for its own manual operation.
Fine small electric actuators are used to control 0° ~ 270° rotating valves and other similar products, such as motorized butterfly valves, motorized ball valves, dampers, flapper valves, plug valves, louver valves, etc. It can be waterproof, adjusted and integrated on-site operation. It can also be controlled by remote 485 protocol and PLC computer.
There are two kinds of explosion-proof and non-explosion-proof products on the market. It can usually be equipped with ball valves below DN200mm (currently the ball float valve on the market can be equipped with DN250mm at most). Soft-seal butterfly valves below DN600 and hard-seal butterfly valves above DN400 (because the soft-seal packing is less and the valve body is lighter, so the torque is small. The hard-seal butterfly plate is a heavy plate of triple eccentric butterfly valve, so a larger torque is required.
It is characterized by high efficiency, no noise, small size, light weight and long service life.
Q type explosion-proof electric actuator is mainly used in flammable and explosive environment. The explosion-proof grade is dIIBT6 and the protection grade is IP68.
The section type can input and output 4-20mA or 0-10V current signals, and can meet the requirements of field integration.
Type Q is currently available in the market, explosion-proof and non-explosion-proof. It can be equipped with ball valves below DN200mm, butterfly valves below DN600 with soft seals and butterfly valves above DN400 with hard seals.
The characteristic is the maximum torque. This type of actuator is suitable for applications with relatively large diameters.
Type Z is also divided into explosion-proof and non-explosion-proof. It can be equipped with ball valves above DN200, butterfly valves above DN600 with soft seal and butterfly valves above DN400 with hard seal. The butterfly valve and ball valve of the Z-type electric actuator must be equipped with a turbine, because the butterfly valve and ball valve usually rotate around 90° (all the left and right rotations are called angular travel). The Z-type electric equipment is operated up and down, and a turbine needs to be added to turn the angular stroke into a straight stroke. For some straight-stroke valve bodies, such as gate valve globe valves, they can be used directly without turbines.
The anti-deviation ability of the electric actuator is very good. The output thrust or torque is basically constant, which can well overcome the unbalanced force of the medium and achieve accurate control of the process parameters, so the control accuracy is higher than that of the pneumatic actuator. If equipped with a servo amplifier, the positive and negative effects can be exchanged easily, and the signal-off valve position state (hold/full open/full close) can be easily set. When it fails, it must stay in place, which is something that a pneumatic actuator cannot do. Air powered actuators must rely on a combined protection system to achieve their position retention.
