Valve Actuators: All you need to know!!!
A Valve actuator is a mechanism or device which operates the valve and its functions. Automated actuators are used on valves where remote operation is preferred like in awkward, inconvenient, hard to reach and dangerous places or for simple sake of convenience in remote operations. Sometimes the valve is in hazardous environment or is contained for no contamination in products and limits the human intervention to manually operate the valves.
Actuated valves also require minimum human effort and can increase the productivity of the facility due to ease and simultaneous operation of numerous valves at once or as per desire. Automation in valves helps by reducing human error by their sophisticated features such as indication of valve position, temperature, pressure, maintenance data and such. They mostly come with a pre-set preferred function (Stay-put, ON or OFF) in case of failure or power outage, some even have alternative power source or options available along with a mandatory manual override.
Let’s talk about types of actuator and their applications.
It is the simplest type of actuator which increases the leverage to operate the valves manually with the help of gears, levers and wheels to move the valve stem. They are self-contained, easy to operate and inexpensive however they can’t operate large size valves or take too much time and effort for the same. The time to operate them is high and is not good in case of emergency scenario.
They are used in Quarter-turn valves, Multi-turn valves and linear valves.
These types of actuators use incompressible fluid (hydraulic oil) to drive the mechanism controlling valves. The hydraulic pressure generated by hydraulic pump is used to push the piston linearly to actuate linear valves or convert linear motion into angular motion for quarter turn valves.
The EHA (Electro Hydraulic Actuator) uses stepper motor to achieve precision in actuation. The electric motor pump directly pressurizes the working fluid to move the piston. The entire system of the pump, cylinder body and the fluid reservoir is designed in a self-contained unit. This power-by-wire system utilizes the pulse-code modulation to control the motion.
The Pneumatic actuator uses compressed air to move a diaphragm or piston to get the motion. This motion operates the linear valves or quarter-turn valves only just like hydraulic actuators. They don’t require too much air pressure to operate the valve like Plug valve, butterfly valve, etc.
This type of pneumatic actuator uses electrical current as signal to control the direction and pressure of valve. The electrical signal maintains the pressure inside the chamber to control the degree of opening or closing. They are used to modulate the flow.
The electric actuator employs an electric motor which provides rotational motion to operate the valves. The torque can be converted into linear motion to operate linear valves along with quarter turn valves and multi turn valves. They are energy efficient, modular, quiet, maintenance-free and non-toxic. They can also be operated on batteries and have a self-contained backup battery for power failure scenarios and emergencies.
These types of actuators use electromagnetic effect to operate the valve. The electric current is the control signal and the actuator moves linearly. This motion is then converted into angular motion if needed. Solenoid actuators are quick, safe, reliable and have long service life. They are only used for open and shut-off operation and on linear or quarter turn valves.
These actuators are contingency measures against emergencies or power failure. The spring is realised if detected anomaly and shuts the valve. They are single time use only and they require less to no power at all to operate during emergencies.
This is it for now folks, as we have covered almost all the types of valve actuators on this part. Cair has a wide range of innovative products for all the industrial applications. We provide other types of actuators upon request with our range of industrial valves too along with gearboxes and limit-switch boxes. See you next time!