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

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.

In 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.

Higher 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.

The 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.

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

Kinetrol Pneumatic Actuators for Portland Cement Production

Cement valve using Kinetrol Actuator

Portland cement is a fine powder, gray or white in color, that consists of a mixture of hydraulic cement materials comprising primarily calcium silicates. More than 30 raw materials are known to be used in the manufacture of portland cement. These materials are chemically combined and subjected to subsequent mechanical processing operations to form gray and white portland cement. Gray portland cement is used for structural applications and is the more common type of cement produced. White portland cement has lower iron and manganese contents than gray portland cement and is used primarily for decorative purposes.

Typically, these raw materials are obtained from open-face quarries, underground mines, or dredging operations.  When mining, pockets of pyrite, which significantly increase emissions of sulfur dioxide (SO2), can be found in deposits of limestone, clays, and shales used as raw materials for portland cement.

Transport of the raw materials is accomplished by a variety of mechanisms, including screw
conveyors, belt conveyors, drag conveyors, bucket elevators, air slide conveyors, and pneumatic conveying systems. A variety of valves, gates, and dampers are required to accurately control the flow of raw materials as they are being discharged from pipes, silos, bins and hoppers. These flow control devices all have one thing in common - the actuators that control their opening and closing are exposed to extremely dusty and dirty atmospheres, with significant amounts of vibration - and they are almost always located in an area where repairs are very costly.

Kinetrol vane actuators are used to automate these gate, butterfly and mixer valves because of their ruggedness and their reliability. Additionally, Kinetrol pneumatic actuators have a smaller footprint and consume less air compared to other pneumatic actuators or conventional linear pneumatic cylinders, resulting in significant savings in energy costs.

Kinetrol USA Wishes the Food and Beverage Industry a "Blue Christmas"

Kinetrol's Neil Meredith standing
next to Kinetrol's "Blue Christmas Tree"
(all the various size Blueline actuators
stacked on top one another.)

Kinetrol USA thinks this Christmas should be "blue" for the foodservice and beverage processing industry. Not blue in the sense of Elvis' sad song, but rather blue in the sense of the new "Blueline" series actuator.

Finally, food and beverage producers have access to the excellent performance of the Kinetrol rotary vane actuators specially coated for use in the harsh wash-down environments common in the food industry.  These actuators comply with the Federal Food, Drug and Cosmetic Act (FDA) and all applicable regulations, including 21 CR 175.300 (Code of Federal Regulations).

The actuators are intended to be installed in areas where harsh chemical wash-down is required. These areas are very tough on most types of pneumatic actuators because the caustic or acidic chemicals used in cleaning adversely effect the actuator.

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