What factors need to be considered when choosing an electric valve actuator?

What factors need to be considered when choosing an electric valve actuator?

Electric valve actuator refers to the mechanical equipment used to drive the valve with electrical energy as the main energy source. The selection of electric actuators is very important, if the selection is not correct, the valve will not operate normally. The selection of electric actuators should consider the following five aspects.

First, determine the control mode of the electric actuator according to the production process control requirements.

The control mode of electric actuators is generally divided into two categories: switching type (open-loop control) and regulation type (closed-loop control).

1. Switch type (open loop control): The switch type electric actuator generally realizes the opening or closing control of the valve, and the valve is either in the fully open position or in the fully closed position, and such valves do not need to accurately control the medium flow.

2. Regulating type (closed-loop control): The regulating electric actuator not only has a switch-type integrated structure to accurately adjust the medium flow, it can also accurately control the valve, which is not detailed here. The following is a brief description of the parameters that need to be indicated when selecting adjustable electric actuators.

a) Control signal type (current, voltage)

b) Working form (electric open type, electric shutdown type)

Second, determine the output torque of the electric actuator according to the torque required by the valve.

The torque required for the valve switch determines how much output torque the electric actuator chooses, generally proposed by the user or the valve manufacturer chooses itself, as the actuator manufacturer is only responsible for the output torque of the actuator, the torque required for the normal opening and closing of the valve is determined by the valve caliber size, working pressure and other factors, but because the valve manufacturer processing accuracy, assembly process is different, so the torque required for the same specification of the valve produced by different manufacturers is also different, even the same valve manufacturer produced by the same specification of the valve torque is also different, The torque selection of the actuator is too small when selected: it will cause the valve to be unable to open and close normally, so the electric actuator must choose a reasonable torque trap.

Third, select the electric actuator according to the valve type.

There are quite a lot of types of valves, the working principle is not the same, generally to rotate the valve plate angle, lifting valve plate and other ways to achieve switch control, when matched with electric actuators should first choose electric actuators according to the type of valve.

Fourth, according to the use of the occasion to choose the shell protection level, coal protection level.

1. Shell IP protection level;

2. Coal proof grade.

Fifth, determine the electrical parameters according to the selected electric actuator.

Due to the differences in the electrical parameters of different actuator manufacturers, so the design and selection generally need to determine its electrical parameters, mainly motor power, rated current, secondary control loop voltage, etc., often negligence in this regard, the result of the control system and the electric actuator parameter mismatch resulting in working time and space tripping, fuse blowing and other failures.