WHAT IS A PNEUMATIC ACTUATED VALVE?

Pneumatic actuated valves used compressed air flowing into and exhausting from an actuator to open and close the valve. The type of pneumatic actuator required depends on the actuator valve. Valves requiring linear motion (gate, globe or diaphragm valves) typically require a pneumatic diaphragm actuator. Quarter turn valves (ball and butterfly valves) typically require either a rack-and-pinion actuator or a scotch yoke actuator. We'll discuss the two types on quarter-turn air actuators in greater detail.Get more news about pneumatic actuated valve,you can vist our website!

Scotch yoke actuators are composed of a piston directly connected to a slotted yoke. A pin on the rotating shaft rides in the yoke slot, converting the linear motion to rotational motion in much the same way a crankshaft converts the linear motion of a piston connecting rod. Scotch yoke actuators have a nonlinear torque profile, with the highest torque at the beginning and end of the stroke. Scotch yoke construction is readily scale-able, making this type of actuator suitable for large pneumatic actuator valves requiring high torque.

Rack-and-pinion actuators use a piston to drive a toothed shaft (the rack) which is geared to the actuator output drive (the pinion). They are typically used in lower torque applications, offer a more precise control and an even torque throughout the stroke.

For purposes of this discussion, we'll focus on quarter turn actuators. Pneumatic quarter turn actuators operate in two different modes: double acting and spring return.

Double Acting

Double acting actuators use compressed gas driving a piston to both open and close the valve. These actuators have two ports to pass and exhaust the gas. Compressed gas is fed through the first port, causing the actuator to close the valve, and then exhausted out the second port. To return to the original position the supply and exhaust functions are reversed.

Spring Return

Spring return actuators typically have a single port to both pass and exhaust the compressed gas. Unlike double acting actuators, spring return actuators are driven in a single direction and, when the gas is exhausted, use springs to return to the original position. The valve can be installed to return to either the closed or open position; the more common mode is normally closed.

Controlling Pneumatic Actuators

As we've seen, actuators with pneumatic action require compressed air to be supplied and exhausted at certain ports at certain times. In the case of double acting actuators, both ports serve as supply and exhaust ports depending on actuator position, and for spring return actuators a single port serves as both the supply and exhaust port. This necessitates some sort of external switching.

This is often accomplished via an external bank of pilot valves. An electronic controller (like a PLC) opens and closes pilot valves which in turn actuate the main air pneumatic valves. However, in large plants or outdoor applications the valve bank may be far from the actuator. In this case long runs of small-diameter pneumatic lines are impractical due to the line pressure loss and the potential for leaks at connections. Instead, it is preferable to run electrical wires directly to the valve and control the valve locally. Compressed pilot air may be supplied by a short run from the piping of the main plant.

Direct mount pilot valves accomplish this by using an electrically actuated solenoid valve to control the compressed gas. The solenoid valve mounts directly to the pneumatic actuator. When energized, the solenoid moves a plunger which directs compressed gas into or out of the valve depending upon configuration.

Double-acting air actuator valves are controlled by solenoid valves utilizing a five port, two position (or 5/2) configuration. The five ports are two output, two exhaust and one input. For spring return control solenoid valves use a 3/2 configuration (one output, one exhaust, one input).

Tagi: electric gate valve 

Why are Industrial Ceiling Lights so Popular?
Be it in office spaces or homes, industrial-style lights are all the rage today.Get more news about Industrial Ceiling Lights,you can vist our website!

These lighting fixtures embrace the simple and strong aesthetic of old factories and industrial spaces. They prioritize functionality, whilst setting the mood of any space they're installed in.

Contrary to popular belief, industrial ceiling lights don't just match the office vibe. You can introduce them into your foyer, your kitchen, as well as your bathroom.

The best part?

Most industrial-inspired style lights come in colors such as matte black, brown, white, and other neutral shades. They're created using unfinished, long-lasting materials such as metal and steel, making for lights that never go out of trend, or style.

We've got a variety of industrial ceiling lights that would be the perfect addition to your space. They come in plenty of styles such as modern, rustic, vintage, farmhouse, and others.

How to Choose the Right Industrial Ceiling Light
Your choice of industrial ceiling lights will vary depending on the kind of setting you want to achieve. If you want to keep things minimalistic, you can buy a simple flush mount light.

For introducing an element of drama to your space, consider opting for a sputnik ceiling light.

In the end, no matter what style you go for, remember to look into the following three factors:

Tagi: electric gate valve 

Why Use Pneumatic Valve Actuators?

Valve actuators, used for operating valves for opening, closing or modulating service, come in a variety of configurations and power sources. Two of the most recognizable types based on these criteria are pneumatic and hydraulic. Each has positives and negatives depending in part on the specific application, space requirements, operating pressures and speeds needed for safe valve operation.Get more news about pneumatic actuated valve,you can vist our website!

Even on a single application, there can be a combination of both pneumatic and hydraulic valve actuators. In remote locations, where neither compressed air nor electricity is available, hydraulic is often the choice.

In refineries, chemical plants and pipeline compressor stations, where compressed air sources are available, the features and capabilities of a pneumatic actuator are usually more favorable.

Pneumatic actuators valve
Pneumatic actuators are designed to operate a piston within a closed cylinder. Pressure from an external air or gas source powers the actuator, moving the cylinder to fully open or close the valve, or partially modulate its open/close movement.

Depending on the valve type, the pneumatic actuator valve can either operate in a 90-degree horizontal direction or in a linear up and down motion.

Hydraulic actuators
Hydraulic actuators operate similarly to pneumatics except the power medium is a non-compressible fluid which, if leaked, can have potentially dangerous effects. Both pneumatic and hydraulic actuators can be configured either with a compressible spring that extends or retracts the piston, or a design with an air or liquid inlet on either side of the piston that allows double-acting operation.

Some of the uses of pneumatic valve actuators
Pneumatic valve actuators are typically used in oil refineries, chemical plants, power plants, water treatment, marine terminals and mining. They are usually made from materials like stainless steel, carbon steel and aluminum.

For industries that have complex pipe and product delivery conduits, stainless steel pneumatic valve actuators are used to manage corrosive liquids.

Precise flow and direction of corrosive liquids, dangerous fluids, and chemicals require robust hardware capable of working under high and heavy payloads. The hardware must also be able to maintain precision movement and flow direction with intricate pipe networks. These systems require the power of pneumatic valve actuators to function properly. Pneumatic actuators offer a range of commercial advantages above and beyond hydraulic actuators.

Tagi: electric gate valve 

SUMMARIZATION OF PLUG VALVE

 

Plug valve is a circumrotating valve with its closure part as a plug, which turns 90 with its through bore connecting to or apart from the same of the body to realize opening or closing. The figure of the valve plug can be made as column or taper.Get more news about pressure balance plug valve,you can vist our website!
Of the column plug valve, the flow bore gets rectangle in general, and that of the taper type plug valve, the flow bore is of trapezium.The figures mentioned have made the structure of plug valves legerity, however, certain loss is at the same time generated.
The plug valve is mostly suitable for cutting off, turning on and distributing the flow medium. Sometime it can also be used for throttling based upon suitable medium and the erosion resistance property of the sealing surfaces. Due to the friction action between the sealing surfaces of the plug valve,whereas contact with flow medium can be completely avoided as the valve is fully opened.In this respect, the plug valve can also be used for the medium with suspend grains.
One of the important characteristics of the plug valve is that it is prone to fitting multi-center structure, so that one single plug valve can be designed with two, three, and even four different flow bores. In this way, the design of the pipeline system can be simplified, and both valve quantity and piping fittings can be reduced. The plug valves are widely used in the applications of oil field exploitation, transportation, and refinery facility, while being extensively used for such general industries as petrochemical, chemistry,gas, nature gas, liquefied oil gas, and warming & traffics.
Lined plug valves without lubricant are used for applications of petrochemical and chemistry industries, especially being used for the medium that is not allowed to be with lubricants.
The face-to-face dimensions of these valves are designed according to Britain and American standards to ensure inter-replacing of valves among different standards. The plug bore of these valves are of reduced bore area, however, the center line position of the plug valves does not change, which generates in the valve body a Venturi action to increase the loss of flow velocity with big percent. The result generated by this action is a corresponding low pressure drop. In this respect,the plug valves can be used in general pipelines, especially used for big sized pipelines to reduce application cost

Tagi: through conduit gate valve