A flow control device used in pipelines and process plants is an industrial valve. The valve’s function is similar to that of a tap, in that it controls the flow of a pipeline by opening or closing. An actuator and control system is added to a valve as part of valve automation. Electric, pneumatic, hydraulic, or human power can be used to power actuators. We are the leading valve industrial automation.
Valve Automation Types
Handwheels, levers, and gears are used when manual energy is used to operate a valve. It isn’t always possible or ideal to use this method, even though they aren’t as costly as other options. Due to high thrust requirements, larger valves can be impossible to operate manually, and other valves can be located in hazardous or remote areas. In addition, if the valve needs to be closed faster than it can be done manually, it can pose a safety concern.
Air pressure or another gas use as the source of power for pneumatic valve actuators. As a result of their simple design, they require minimal maintenance and can use in extreme temperature applications.
Failure action in pneumatic systems
Failures in valve control systems are often describ as Fail Open, Fail Close, and Fail in the last position. A failure will cause the valve to take one of these positions, so to understand what is going to happen after a failure, let’s first define what types of failure exist.
Two types of failure can occur in a pneumatic valve automation system; A signal failure, which is usually an electrical signal of low voltage, e.g., an electrical signal to the solenoids, is known as a signal loss. The loss of energy or power occurs when the source of energy used to move the valve actuator fails, which in pneumatic systems is the pressurized gas.
Single-acting pneumatic actuators
The last position failure can achiev if energy is lost during actuator movement; however, if opening or closing requir after the failure, there is no energy to move the actuator.
An external source of energy requir in these cases. In valve automation, pre-compress springs, also called single-acting actuators, are the most common store energy system.
A pneumatic actuator with an air spring that fails safely
Spring systems are no longer a practical option for systems that require a high amount of energy, such as thrust valves or torque valves. For pneumatic systems, we often use air-spring fail-safe systems, which store pressurized fluids. As a result of a power outage or loss of plant air supply pressure, these systems use pressurized gas to move actuators between open and closed positions.
Depending on the volume of air displac the actuator, the maximum pressure at which the actuator operates, and the minimum pressure need operate the actuator, the size of the tanks will depe on the amount of air to store. It is also possible for tanks to reach large sizes when storing large volumes of air. To solve this problem, pneumatic pressure boosters can use.
Aira Euro Automation is the leading valve industrial automation in India. We offer various types of industrial valves like ball valves, butterfly valves, control valves, globe valves, and many more.
The hydraulic actuator converts fluid pressure into motion, similar to pneumatic actuators. Their high-force capabilities make them ideal for high-force applications. Actuators can operat by hydraulic pressure suppli the process fluid itself in some applications.
To operate the valve, electrical energy convert into torque by the electric actuator. Their precision-control positioning is also extremely quiet, non-toxic, and energy-efficient. In contrast, they are expensive and unsuitable for critical applications requiring high speeds or failure modes.
Pneumatic pressure boosters
Pneumatic pressure boosters are 100% mechanical devices that boost pneumatic pressure as their name implies. As air at X pressure introduc to the booster, the pressure activates the mechanical components of the booster and increases the inlet pressure with an internal piston.
In the compression volume, the thrust volume contains the piston that moves the piston and compresses the air. Depending on the ratio at which the pressure is to amplifi, the compression volume calculat. An amplifier with a 2:1 ratio will have a larger area than one with a 3:1 or 4:1 ratio, for example. Upon reaching the end of the stroke, the piston begins to move in the opposite direction, and the booster continues moving in this cyclic motion until the ratio of 2:1, 3:1, or 4:1 is reach.
How do boosters work when used as part of valve automation failure systems?
When pressure enters the booster, it increases it according to its design ratio according to its inlet connection to the main airline and outlet connection to the storage tank. In this case, we will have 240 PSIG output to the tank if the booster is 4:1 and the inlet pressure is 60 psi-g. 240 psi-g of pressure is then appli to the tank to store the air.
When the plant’s air pressure is working normally, the valve can operat by the regular air pressure supply, or if this is not available, the valve can operat by pressuriz air in the tank. In this case, 240 psi-g, since the booster operates mechanically when the air pressure falls below the set point, the booster will activate once regular plant pressure is available to restore 240 psi-g to the air pressure.
By storing air at a higher pressure in the tank, a pressure booster allows the tank and actuator to be significantly smaller.
The valve actuator plays a significant role in automating process control. Depending on their design, they can fail-open, fail-close, or fail last. Water treatment plants, power plants, mining, and nuclear processes, food factories, refineries, and pipelines all use actuators. A wide range of valve actuators designed for severe service is available from Cowan for applications such as oil & gas, petrochemical, power generation, mining, and aerospace.