1/4 Turn Electrohydraulic Valve Actuators

A hydraulic gear pump immersed in its own reservoir delivers pressurized oil to the vane-type 90° actuator via the control box, which contains non-return valves and solenoid valves to direct the flow into the actuator; with cam operated limit switches to control travel and (optionally) signal position to the user. The unpressurized side of the actuator is connected to the reservoir, so there is no net transfer of oil from reservoir to actuator. The pump and its motor run entirely on precision ball bearings, so that the friction and motor size can be minimized and life maximized; the efficiency resulting from this reduces the heating effect and allows 100% rating. A pressure release valve is built into the pump so that if the actuator load becomes jammed the torque is limited and dangerous over pressures or motor stalls are avoided.

Fail-safe spring return action uses a reliable low-stress-range sealed clock-type spring unit mounted coaxially with the actuator, together with a fail-open solenoid valve, to ensure reliable positioning when power is not supplied to the unit. A high flow external dump valve can be fitted to allow very rapid spring-driven action.

Double-acting models are supplied with solenoids arranged to give position locking when power is disconnected. An optional manual by- pass valve is available to allow manual override movement of a double acting when power is disconnected.

The interface between pump/reservoir unit and the control box allows mounting of the pump in different orientations at 90° to each other, so that the motor can be kept above the reservoir whether the actuator output axis is horizontal or vertical. External electrical connections are all made via a single accessible connector block in the control box, with the simplest possible switching needed to drive the unit. Two conduit entries are available, to allow easy separate connection of power and signal lines (if used). All internal wiring is connected via a central connector and fuse board, and the actuator is protected from supply surges by a metal oxide varistor suppressor.

For more information contact:

Kinetrol USA
www.kinetrolusa.com
972-447-9443

Valve Automation Package for Tough Hog Fuel Boiler Applications

Hog fuel boiler actuator.

Hog fuel boilers are wood-fired boilers used predominantly in paper mills, sawmills, and wood processing plants. The term “hog fuel” refers to the wide variety of wood and wood wastes used to feed the boilers (called hogged fuel). Hog fuel contains wood residue, wood waste products, bark, sawdust, planer shavings, and wood chunks that are processed into coarse chips and clumps.

The ash from burning wood and wood wastes has a very high pH, high enough to make the wood ash exhibit a corrosive characteristic, which must be considered when selecting valves and actuators. All equipment in contact, or in close proximity, to this ash must stand up to the wet, corrosive, and dirty environment.

To facilitate the removal and transport of the ash, water is introduced for handling and management, thus creating corrosive slurries. Control valves with pneumatic actuators are used to control water flow and slurry flow. The environment is extremely dirty, and as mentioned above, corrosive. Any equipment connected to this process must be designed with performance and maintenance in mind.

Kinetrol rotary vane actuators, spring return units, and EL positioners are ideal for this type of service. Standard design features such as epoxy enamel finishes, stainless steel screws, sealed housings, and direct mount configurations provide an automation package that is proven to outlast other types of actuators and assemblies in very challenging environments.

Does Your Valve or Damper Need More Than 90 Degrees Rotation?

180 degree actuator

Kinetrol’s 180° actuator is produced by adding a 2:1 step-up linkage onto the output shaft of well proven 90° vane actuators.

Factory fitted, direct mount linkage units are available to suit model 02, 03, 05, 07, 09, 12, 14 and 16 actuators, giving a neat single unit with no mount kits or brackets. The linkage’s unique geometry gives constant 2:1 step-up so that the output torque remains constant throughout the actuator's travel.

The all-steel mechanism of the linkage employs rolling contacts to minimise frictional losses and wear, and to maximise life. The linkage is lubricated for life, and encased in a robust, fully sealed die cast alloy casing. Exterior surfaces are protected by a corrosion resistant epoxy stove enamel finish. Standard adjustable endstops on the 90 degree actuator can be used to set the angle of travel. The other end of the 90 degree actuator allows the full range of Kinetrol modular accessories to be fitted directly.

• Simple compact unit - No external moving parts
• Unique linkage design - converts to 180° travel 120° option available 
• Constant gear-up ratio through travel range - Hence constant output torque 
• Rolling contact linkage mechanism - Ensures low wear, long life, low friction 
• Linkage sealed for life - Protected from the environment, long maintenance free life 
• Compatible with all Kinetrol modules - Direct mounted spring returns, limit switch boxes, positioners etc.
• Adjustable endstops

180 Degree Rotary Vane Actuator from Kinetrol USA

6 Reasons Why Pneumatic Vane Actuators are Superior to Rack and Pinion Actuators

Rotary vane actuators offer distinct design and performance advantages.

1. Rotary vane actuators do not convert linear motion to rotary motion, unlike rack and pinion actuators. No additional gearing is required and no side loading is transferred to the actuator housing.
2. Vane actuator lip seals are the key to long life. The double opposing lip seal design, with stainless steel expanders, provides unmatched service life by using air pressure to improve the actuators seal-to-enclosure contact, and provide a “self cleaning” effect on the epoxy or PTFE internal finish.
3. The elimination of pressure bearing o-ring shaft seals. Rack and pinion actuators require shaft sealing o-rings that are exposed to the full supply air pressure used to operate the actuator. These o-rings wear, causing leaks, a drop in efficiency, and wasted energy through air consumption. Vane actuators' double opposing lip seals isolate the supply air pressure from the actuator shaft, requiring only a low friction bearing on the shaft.
4. Rotary vane actuators provide superior modulating accuracy. Because of the integral vane and shaft (machine from a single casting), lost motion or hysteresis is reduced dramatically which intern provides much tighter modulation and control. The vane actuators inherent low friction also reduces hunting and sticking.
5. Direct mount, modular design for springs, positioners, switches, and solenoids reduce space requirements and lower inventory costs. Since vane actuator accessories direct mount to various size actuators, there’s no need to inventory and keep track of mounting kits. 
6. Rotary vane actuator spring return units are designed to be virtually indestructible. Using low stress, clock springs reduces spring tension loss and metal fatigue. The housing for vane a actuator springs are sealed from the atmosphere, preventing corrosion of internal parts. Most importantly, these type of spring units provide the lowest torque loss which enables the section of smaller (less expensive) actuators.

Tough Actuator Service on Paper Plant Green Liquor Line

Pulp and Paper Plant

It's said the only thing a pulp and paper plant doesn't reuse is the "shade the building casts". The processes used in the production of pulp and paper are very efficient when you consider the reuse of energy and by-products. The efficiency comes at a cost though - through very hostile atmospheres and demanding operating conditions for process equipment.

For example, the "kraft process" (also known as the sulfate process) is the method to convert wood chips into pulp and then to cellulose fibers. This is done by mixing the wood chips with sodium hydroxide and sodium sulphate, soaking, cooking and processing.

Here's a very basic explanation of the kraft process. Wood chips are soaked and processed in sodium hydroxide and sodium sulphate mixture known as "white liquor".  After the wood chips are impregnated with white liquor, they are then cooked in digesters to break the wood down into cellulose. The solid pulp is then separated and the remaining fluid is referred to as "black liquor". Black liquor is further processed to remove solids and chemicals which are to be re-used in the pulping process. One of the final by-products is "green liquor" which contains sodium carbonate and sodium sulfide and is then reacted with lime to regenerate more white liquor.

All of these steps expose process equipment, piping, and valves to very tough environments. Kinetrol actuators are preferred in these situations because they don't allow corrosive atmospheres to penetrate the actuator or springs, their long cycle life,  and their epoxy stove enamel finish.

Below is a picture of a Kinetrol model 14 double acting actuator on a 8” full-port ball valve on a green liquor line. The valve cycles 2 times per day to direct green liquor flow and weak wash (weak white liquor) alternatively from one pipe to another in order to prevent solids build up in the pipelines.

Kinetrol Model 14 in Green Liquor Line

Don't Get Racked Up ... Use Kinetrol Vane Actuators

Little video "commercial" about the virtue of Kinetrol Vane actuators over pneumatic rack and pinions actuators ...

Kinetrol vane actuators provide:

• Single moving part - Simplest and most reliable mechanism for quarter-turn rotary actuation.
• Close couple control modules - Fail-safe spring returns, limit switches, positioners and solenoid valves all close couple to the actuators.
• No cranks or gearing - No power loss or backlash - allows accurate positioning.
• Durable corrosion resistant finish
• Long maintenance-free life - Up to 4 million operations guaranteed.
• Compact - space saving - efficient: Best torque/size package available, fast operating speeds, best air consumption, proven design.

The Virtues of the Pneumatic Vane Actuator Damper Drive

Pneumatic damper drives

Pneumatic damper drives significantly improve the reliability, precision, and efficiency of industrial boilers and furnaces. Accurate control of combustion air and flue gas provide many cost savings benefits to plant operators. A pneumatic damper drive’s precision and rapid response greatly improve fuel efficiency, reduce emissions, lower fuel consumption, and provide better boiler draft control.

Recent “Boiler MACT” (Boiler Maximum Achievable Control Technology) regulations require regular maintenance to optimize boiler performance. Air-to-fuel mixing and CO emissions are two areas where fine tuning and precise control yields dramatic improvement in burn efficiency. Old electric drives do not provide the precision, speed or torque needed for accurate control, so a retrofitting program that replaces electric drives with pneumatic units is an easy way to improve efficiency and gain better performance.

In the application outlined below, several dual-arm damper drives, using Kinetrol Model 18 actuators, were specified to replace aging Bailey electric damper drives in a power plant in the southwest USA. These specific drives are used to control the desuperheater and reheater temperature at a gas fired plant. Not only was there a need for optimized performance for better fuel consumption and lower emissions, but the customer was also very concerned about reliability. The plant needed to know the new Kinetrol-based damper drives were immediately available, and ready for drop-in replacement as the Bailey drives failed. This was easily managed by designing pedestals and frames that matched the bolting patterns and envelope size of the existing Bailey units. The Kinetrol drives were designed to match the legacy footprint exactly, have the drive shaft and drive lever in the exact position, and provide a drive shaft and lever with the same dimensions as the Bailey drive.

The result is a high duty cycle, highly precise, long-life, fast acting, responsive, easily maintained, and easily automated damper drive.