Showing posts with label Rotary vane actuator. Show all posts
Showing posts with label Rotary vane actuator. Show all posts

Thursday, June 28, 2018

The Most Reliable 1/4 Turn Pneumatic Actuator on the Market Today. Period.

With millions of actuators performing reliably around the world, the Kinetrol vane actuator's outstanding cycle life, smooth and precise movement, and environmentally rugged design makes it the best choice for all of your valve actuation needs.



Saturday, April 28, 2018

Pneumatic Valve and Damper Actuators: A Design Comparison

Industrial valve applicationIndustrial valves, dampers and louvers are operated either electrically or pneumatically. This post compares the three major categories of  pneumatic valve actuators, namely:
  1. Rotary vane
  2. Scotch-yoke
  3. Rack & pinion
All three categories provide the same basic function - converting air pressure to rotational movement intended to open, close, or position a quarter-turn valve (ball, plug, butterfly), louver or damper.

All three can be configured in either direct acting or spring return versions. Direct acting actuators use the air supply to move the actuator in both directions (open and close). Spring return actuators, as the name implies, uses springs to move the actuator back to its "resting" state. Converting from direct acting to spring return is done through simple modifications, typically just adding an external spring module, or removing the end caps from rack and pinion actuators and installing several coil springs.

Vane Actuator
Rotary Vane Actuator

Rotary Vane Actuators

Vane actuators generally provide the most space savings when comparing size-to-torque with rack and pinion and scotch yoke. They have an outstanding reputation for long life because then contain only one moving part, as opposed to rack and pinion and scotch yoke actuators that have many. They tend to withstand dirty and corrosive atmospheres better than rack and pinion and scotch yoke actuators. Vane actuators also use externally mounted, helically wound "clock springs" for their spring return mechanism.

Scotch YokeScotch Yoke

Scotch-yoke actuators use a pneumatic piston mechanism to transfer movement to a linear push rod, that in turn engages a pivoting lever arm to provide rotation. They come in a wide variety of sizes, but are very often used on larger valves because they are capable of producing very high torque output. Spring return units have a large return spring module mounted on the opposite end of the piston mechanism working directly against the pressurized cylinder.

Rack and Pinion

A rack & pinion pneumatic actuator uses opposing pistons with integral gears to engage a pinion gear shaft to produce rotation. Rack & pinion actuators (sometimes referred to as a lunch box because of their shape) tend to be more compact than scotch yoke, have standardized mounting patterns, and produce output torques suitable for small to medium sized valves. They almost always include standard bolting and coupling patterns to directly attach a valve, solenoid, limit switch or positioner. Rack and pinion actuators use several smaller coil springs mounted internally and provide the torque to return the valve to its starting position.

The practical difference between these three types of pneumatic actuators comes down to size, power, torque curve and ease of adding peripherals. For the best selection of valve actuator for any quarter turn valve application, you should seek the advice of a qualified valve automation specialist. By doing so your valve actuation package will be optimized for safety, longevity, and performance.

Scotch yoke mechanism image courtesy of Wikipedia.
Rack and pinion mechanism image courtesy of Wikipedia.

Wednesday, December 13, 2017

Kinetrol Actuator Feature Video

Here's a new Kinetrol vane actuator feature video. Please take a minute to watch. Hope you enjoy.

Thursday, November 30, 2017

Vane, Shaft and Seal Design: The Critical Difference in Pneumatic Rotary Valve Actuators

lower quality vane
Kinetrol
Click images for larger view.
The vane actuator produces rotary motion through the application of air pressure to a "vane' attached directly to an output shaft.

There are several manufacturers of pneumatic, rotary vane valve actuators on the market. Outwardly they appear similar. Internally, there's a world of difference in their design and their performance.

2 piece vanelower quality vaneIn higher quality vane actuators, the vane and shaft are machined from a single piece of steel. Casting and machining adds cost, but also adds performance. Lower quality actuators save cost by using a 2-piece vane/shaft combination. These are more likely to be affected by backlash or lost motion.  In other words, a one-piece shaft and vane assembly transfers 100 percent of the vane movement directly to the shaft. Two-piece designs may lose movement over time, reducing control and accuracy.

Kinetrol vaneHigher quality pneumatic vane actuators incorporate a pair of “lip seals” around the vane. The durable and resilient polyurethane seals provide two key benefits; eliminating the need for o-rings; and eliminating shaft seals. Dual, opposing lip seals are located each side of the vane. They isolate the vane and shaft from the air supply and create an area from the shaft through the center of the vane that remains unpressurized, eliminating the need for pressure seals around the top and bottom of the shaft.

Some lower quality vane actuator designs use an o-ring around the entire vane, exposing the o-rings to mechanical stress and rolling. Higher quality actuators back their polyurethane lip seals with stainless steel expanders that maintain the integrity of the seal to the actuator housing.

Kinetrol vaneThe heart of the pneumatic vane actuator is simple design. Manufacturers often promote the concept of "a single moving part", referring to the vane/shaft/seal assembly. But despite this claim, all pneumatic vane actuators are not the same. You owe it to yourself and your organization to "look under the hood".  See what level of engineering and quality you're really getting.

Monday, November 27, 2017

How Kinetrol Pneumatic Rotary Vane Actuators Work

Kinetrol pneumatic rotary vane actuators use a one piece vane and shaft produce rotary torque on the shaft output drive. The vane is assembled inside a 2-piece clam-shell enclosure. The presence of the vane creates two air chambers. By pressurizing and venting opposing chambers, the resulting pressure differential across the vane provides torque to the shaft. Torque output of the rotary vane actuator remains constant throughout the full rotation of the shaft.

http://www.kinetrolusa.com | 972-447-9443

Tuesday, October 10, 2017

9 Kinetrol Features Providing Unmatched Actuator Performance

  1. Long life epoxy or PTFE internal finish
  2. Easy stop adjustment at each end of stroke for accurate seating
  3. Corrosion resistant zinc (non-incendive) or aluminium alloy case
  4. Integral vane/shaft casting - only one moving part
  5. Manual override square and position indicator
  6. Stainless steel expanders ensure long term lipseal / case contact
  7. Double opposed, Polyurethane, lip seals for effective sealing and long maintenance free life
  8. Space filling/energy absorbent sideplates (polymer or metal)
  9. Durable epoxy stove external enamel finish


Kinetrol USA - http://www.kinetrolusa.com | 972-447-9443

Monday, August 28, 2017

Dampers and Louvers Used in Power Plants, Refineries, Boilers, and Furnaces

parallel damper
Parallel damper with electric actuator.
A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large flows of air at low pressure. Dampers find common application in furnace and boiler draft control, and in HVAC (Heating, Ventilation, and Air Conditioning) systems.

Radial damper
Radial damper.
Common damper designs include parallel and radial. Parallel-vane dampers resemble a Venetian blind, with multiple rectangular vanes synchronously rotated to throttle flow through a rectangular opening. A photograph of a parallel-vane damper is shown above, part of an induced-draft (suction) air fan system on a separator at a cement plant. The vanes are not visible in this photograph because they reside inside the metal air duct, but the electric actuator mechanism and linkages connecting seven vane shafts together are visible.
pneumatic vane actuator damper drive
Pneumatic vane actuator damper drive.

Radial-vane dampers use multiple vanes arranged like petals of a flower to throttle flow through a circular opening. A photograph of a radial-vane damper is shown here (note the levers and linkages on the periphery of the tube, synchronizing the motions of the eight vanes so they rotate at the same angle).

Dampers are opened and closed by electric or pneumatic drives. In recent years, the pneumatic vane actuator  has earned an reputation for modulating dampers. Used in critical applications commonly found in power plants, refineries, boilers, and furnaces, these unique damper drives provide precise combustion gas management, are proven to increase boiler efficiency, lower fuel consumption, reduce emissions, and reduce maintenance cost.


Parts of this post are reprinted from Lessons In Industrial Instrumentation by Tony R. Kuphaldt – under the terms and conditions of the Creative Commons Attribution 4.0 International Public License.

Saturday, July 22, 2017

Shark-Tested Rotary Vane Actuators

For those of you who live under a rock, Shark Week  is a week long TV programming block put on by the Discovery Channel. Usually occurring in mid-late July or early August, it features entirely shark-related programming. Everything from great educational documentaries to completely ridiculous events such as Micheal Phelps racing a Great White.

So what does a blog about rotary vane actuators have to do with Shark Week? The answer lies with the good people at MythBusters.

Out to prove (or disprove) the long-standing theory that punching a shark in the nose will scare it away, host Jamie Hyneman had to design a robotic shark punching machine that would deliver a powerful punch, similar to one that a real human being would deliver.

As they have in a past MythBuster episode, the MythBusters team turned to Kinetrol for the crucial piece of equipment - the Kinetrol pneumatic rotary vane actuator.

The result was an underwater "Rock 'em Sock 'em Robot" machine with two arms, each powered by a Kinetrol Model 07 Actuator.






Saturday, July 15, 2017

How Kinetrol Pneumatic Rotary Vane Actuators Work

Kinetrol pneumatic rotary vane actuators use a one piece vane and shaft produce rotary torque on the shaft output drive. The vane is assembled inside a 2-piece clam-shell enclosure. The presence of the vane creates two air chambers. By pressurizing and venting opposing chambers, the resulting pressure differential across the vane provides torque to the shaft. Torque output of the rotary vane actuator remains constant throughout the full rotation of the shaft.

Sunday, July 9, 2017

Industrial Dampers and Drives

Round dampers with pneumatic vane type drives
Round dampers with
pneumatic vane type drives.

By definition, a damper is a device used to control pressure, flow, or flow direction in an air or gas system. Different types of dampers can be used, depending on specific functional requirements. Table 5.7 below lists the types of dampers and their functions, and Table 5.8 lists the damper configurations. Selection of the proper damper type and blade configuration is important to achieve the required damper performance. The type and configuration of damper can significantly impact pressure drop, leakage rates, and controllability.
dampers by function
Click table for larger view.

dampers by type
Click table for larger view.

pneumatic vane damper drive
Pneumatic vane damper drive.
A very important part of damper design is determination of damper torque and sizing and selection of damper actuator for the maximum torque. Actuator torque should be selected for a minimum of 1.5 times the damper maximum torque to provide margin and allow for degradation over the life of the damper. Actuators should be evaluated for damper blade movement in both directions, at the beginning of blade movement, and while stroking blades through the full cycle of movement.

Damper operators can be one of three types: pneumatic, electric, or electro-hydraulic, as described below.
  1. Pneumatic. These damper operators are used whenever controls rely primarily on compressed air (pneumatic) for moving operators or transmitting control signals.
  2. Electric. These damper operators are used whenever controls rely primarily on low voltage electric circuits to transmit control signals.
  3. Electrohydraulic. These damper operators are the same as the electric type described above, except they have the ability to modulate. They use an electric control signal to position a hydraulic system that, in turn, positions the damper.
Electrically operated damper drives have historically been favored, but the shift to retro-fit electric drives with pneumatic damper drives has been significant in the last two decades. When pneumatic vane actuators were first introduced for damper drive service, their virtues were quickly discovered. Their inherent design and operating advantages apply perfectly for precise damper control. These design and operating advantages are:
  • Damper drives on round dampers.
  • Precise, smooth signal to movement response.
  • 100 percent duty cycle.
  • Continuous modulating service.
  • No overheating.
  • High speed/high-torque.
  • Fast full stroke open/close.
  • Very easily serviced.
  • Excels in harsh, high-temperature operating environments.
  • Effectively zero air consumption in resting state.
For more information on any damper drive application, contact Kinetrol USA at 972-447-9443 or visit http://www.kinetrolusa.com.

Wednesday, May 24, 2017

Why Vane Actuators Are Better - We'll Make This Easy

With millions of actuators performing reliably around the world, the Kinetrol vane actuators' outstanding cycle life, smooth and precise movement, and environmentally rugged design makes it the best choice for all of your valve actuation needs.

The rotary vane actuator design is based upon a single moving part which eliminates additional parts required to convert linear motion to rotary motion. This simple and innovative design provides a highly accurate and extremely reliable actuator for operating valves, drives and dampers, and is perfectly suited for the most demanding process control control applications.

Wednesday, April 19, 2017

Lower Total-Cost-of-Ownership in Poor Process Environments with Pneumatic Vane Actuators

Kinetrol
Design advantages for use in poor process conditions (click for larger view).
Clean, dry instrument air is critical for pneumatic instruments and actuators to work properly. In remote, dirty process control environments, like refineries, chemical plants, power plants, water treatment facilities, pulp & paper mills, or mining facilities, providing clean instrument air is challenging,  costly and problematic.  Along with poor instrument air, the ambient air in these areas is generally filled with dust and contaminants. Process equipment must be engineered to withstand these conditions, and devices with low tolerance to dust, dirt, condensate, and poor ambient air quality (such as rack and pinion actuators) are to be avoided. Devices in these areas are costly to maintain as shut-downs and repairs are very expensive.

For the operation of pneumatically controlled valves, and as a better alternative to rack and pinion actuators, Kinetrol rotary vane actuators are an excellent choice. Their simple design, with one moving part, and an elegantly engineered vane, inherently protects the actuator from bad instrument air. Kinetrol's use of double opposed polyurethane lip seals, backed by stainless steel expanders, ensure long-term lip seal contact and effective sealing for years of maintenance free life. The vane, lip seals, and expanders actually provide a self-cleaning, or wiping, mechanism for any moisture, dirt or dust entering the interior of the actuator. In effect, the vane actuator's design "sweeps away" the debris that will cause other actuators to fail.

A considerable cost savings can be calculated given the trouble-free performance Kinetrol vane actuators provide. Assuming both a Kinetrol and standard rack and pinion actuator cost approximately the same, and that the life of a typical rack and pinion actuator in these environments is approximately 1 year, you can easily see the savings. By factoring in the replacement cost for an new actuator, and the cost of labor to install, you’ll find a standard rack and pinion is at least 2.5x the cost of Kinetrol over a 2 year period.

Kinetrol actuators have a well-earned reputation for operating trouble-free for years in the most difficult environments. Considering their years of maintenance-free service, it’s easy to understand the significantly lower total-cost-of-ownership they deliver.

For more information, visit Kinetrol USA at http://www.kinetrolusa.com or call 972-447-9443.

Sunday, February 26, 2017

Avoid Fretting and Backlash with Rotary Vane Actuators

fretting and backlash shorten actuator life
Fretting and backlash
shorten actuator life and
negatively affects controllability
over time.
The American Society for Metals Handbook on Fatigue and Fracture defines fretting as: "A special wear process that occurs at the contact area between two materials under load and subject to minute relative motion by vibration or some other force."

In pneumatic valve actuators, fretting wear is caused by the repeated cyclical rubbing between gears in scotch yoke or rack and pinion actuators. Over a period of time, fretting will remove material from one or both surfaces. This extra material, or debris, is usually harder than its source material due to work hardening and oxidation. The resulting debris becomes an even more effective abrasive, increasing the rate of mechanical wear and continued fretting.

Backlash happens when gears change direction. It is caused by the gap between the trailing face of the driving tooth and the leading face of the tooth behind it. The gap must be closed before force can be transferred in the new direction, hence the phenomena of backlash. This is also sometimes referred to as "slop".

Both fretting and backlash significantly effect the service life of an pneumatic valve or damper actuator. Both are also detrimental to controllability when actuators are used to accurately manage the percent open status of a valve or damper.

rotary vane actuators
Internal view of a rotary vane actuators.
Notice the vane is constructed from
a single piece of stock and
contains no gears.
An alternative actuator design is the rotary vane design that uses a single piece of machined steel for both the vane body and drive shafts. With this design, the shaft and vane are not affected by backlash, friction or wear. Vane actuator's incorporate a design with only a single moving part that provides very repeatable, smooth movement that will not decay over time.

For more information, visit http://www.KinetrolUSA.com or call 972-447-9443.

Monday, January 30, 2017

Rotary Vane Valve Actuators

Rotary vane actuator
Rotary vane actuator
A rotary vane actuator is simply a part of an automated valve assembly: its role is to change the position of the valve, converting the motive force of fluid pressure into torque and applying it to a valve stem.

Quarter turn valves are widely used in industrial process automation. Their application is primarily for operations requiring fully open or fully closed valve trim positions, although some do provide modulating service. A rotation of the valve stem through a 90 degree arc will reposition quarter turn valve trim between open and closed positions. A rotary vane actuator is well suited for driving this type of valve, with its own 90 degree arc of movement.

A rotary vane actuator operates quarter turn valves, dampers and louvers. A pressure tight housing contains a movable vane which is sealed to the sides of the pressure chamber by means of a low friction gasket. Inlets into the chamber on opposing sides of the vane allow a controller to produce a pressure differential across the vane. The vane will move, in response to the pressure differential, in either direction. A shaft is connected to the vane and the vane acts like a lever to rotate the shaft as the vane is moved by fluid pressure. The torque produced by the actuator assembly is primarily dependent upon the applied fluid pressure.

Hydraulic rotary vane actuators have the ability to handle large amounts of fluid and dynamic motions, exhibiting also qualities of durability and compactness. Pneumatic vane actuators use plant air pressure as the motive force. Both types generally have few moving parts and require little regular maintenance. A variety of typical automation accessories and options are available to customize a unit for a particular application.