Commissioning the ROTORK CK Range Valve Actuators

The Rotork CK actuator range has been designed to meet the needs of diverse actuation applications required by the valve industry and its customers. The modular design concept enables quick product configuration from stock to customer specification with a very short lead time. 

The CK range provides the customer with a range of options to suit all of their actuation requirements. Rotork CK actuators are designed for minimum user interaction. Their primary goal is to provide safe and reliable actuation in harsh environments. 

The modular CK product range offers simple, robust actuators (CK/CKr) suited to harsh environments with the option for two different control packages (Atronik and Centronik) to meet exact site requirements. Atronik offers modest control and feedback for a simple integrated starter solution. Centronik offers advanced control and feedback for more complex site system integration and increased flexibility through remote mounting. 

For questions about all ROTORK products in Northern California and Nevada, contact CTi Controltech.

https://cti-ct.com
925-208-4250

The Flowserve Logix 3800 Digital Valve Positioner

The Logix 3800 positioner features powerful diagnostics that identify field problems and expedite corrective actions to ensure reduced return-to-operation times.

Compatible with linear and rotary valves and actuators, the robust design of the Logix 3800 delivers high reliability in tough environments, reduces inventory costs and contributes to a lower total cost of ownership, and installs with an innovative, one-button quick calibration feature.

Partial List of Features:

• Rugged, certified SIL 3 capable modular design delivers maximum reliability in the toughest environments. 
• Installation and operation ease from innovative quick calibration feature to simplify commissioning. 
• Broad application versatility with industry-leading communication technologies, including analog, HART, Foundation Fieldbus, 4-20 or discrete I/O signals.
• Intrinsically safe, non-incendive and explosion-proof design from -52°C to 185°C (-62°F to 365°F) ensures safe, reliable operation in hazardous conditions for increased plant and personnel safety.
• Compatible with a variety of valve and actuation configurations including: rotary or linear valves; double- or single-acting; air- to-open or air-to-close.

https://cti-ct.com
925-208-4250

Pneumatic Control Valve Positioners

Smart valve positioner
Courtesy Rotork

Valve positioners can provide process operators with a precise degree of valve position control across the valve movement range, as well as information about valve position. A relationship exists between applied pneumatic signal pressure and the position of the valve trim. The relationship between the two elements is dependent upon the valve actuator and the force of the return spring reacting to the signal pressure. In a perfect world, the spring and pneumatic forces would reach equilibrium and the valve would return to the same position in response to an applied signal pressure. There are other forces, however, which can act upon the mechanism, meaning the expected relationship between the original two elements of pressure and position may be offset. For example, the packing of the valve stem may result in friction, or the reactive force from a valve plug resulting from differential pressure across the area of the plug may be another.
While these elements may seem minor, and in some cases they are, process control is about reducing error and delivering a desired or planned output. Inclusion of a positioner in the valve assembly can ensure that the valve will be set in accordance with the controller commands.

Each positioner functions as a self-contained small scale control system. The first variable in the positioning process is the current valve position, read by a pickup device incorporated in the positioner. A signal which is sent to the positioner from the control system, indicating the desired degree of opening, is used as the setpoint. The controller section of the positioner compares the current valve position to the setpoint and generates a signal to the valve actuator as the output of the positioning process. The process controller delivers a signal to the valve, and then the positioner takes that signal and supplies air pressure required to accomplish the needed adjustment of the stem position. The job of the valve positioner is to provide compensatory force and to act as a counterbalance against any other variables which may impact valve stem position.

Magnetic sensors can be employed to determine the position of the valve stem. The magnetic sensor works by reading the position of a magnet attached to the stem of the valve. Other technologies can be employed, and all have differing ways of overcoming degrees of inaccuracy which may arise with wear, interference, and backlash. In addition to functioning as a positioner, control valve positioning devices can also function as volume boosters, meaning they can source and subsequently ventilate high air flow rates from sources other than their pneumatic input signal (setpoint). These devices can positively affect and correct positioning and velocity of the valve stem, resulting in faster performance than a valve actuator solely reliant on a transducer.

The inclusion of a positioner in a control valve assembly can provide extended performance and functionality that deliver predictable accurate valve and process operation. Share your valve automation requirements with a knowledgeable valve automation specialist and combine your process knowledge and experience with their product application expertise to develop an effective solution.

CTi Controltech In-House Capabilities and Solutions for Combustion, Automation, and Instrumentation

CTi Controltech has operated in northern California and Nevada for many years, satisfying customers and building their capabilities into today's top flight provider of equipment and services to industrial and commercial markets. The short piece included below is a synopsis of the company's range of products and services.

Share your combustion, emission, steam, process control, and automation challenges with experts in the field. The combination of your own process knowledge with the expertise at CTi Controltech will produce effective solutions.

CTi Controltech In-House Engineering Capabilities For Combustion and Process Control from CTi Controltech

Application of Limit Switches on Automated Industrial Valves

Employed in a wide range of industrial applications,

limit switches are known for ease of installation,

simple design, ruggedness, and reliability.

Courtesy Flowserve Automax

Limit switches are devices which respond to the occurrence of a process condition by changing their contact state. In the industrial control field, their applications and product variations are almost countless. Essentially, the purpose of a limit switch is to serve as a trigger, indicating that some design condition has been achieved. The device provides only an indication of the transition from one condition to another, with no additional information. For example, a limit switch triggered by the opening of a window can only deliver an indication that the window is open, not the degree to which it is open. Most often, the device will have an actuator that is positively activated only by the design condition and mechanically linked to a set of electrical contacts. It is uncommon, but not unknown, for limit switches to be electronic. Some are magnetically actuated, though most are electromechanical. This article will focus on limit switch designs and variants used in the control and actuation of industrial process valves.

Valves, devices used for controlling flow, are motion based. The movable portions of valve trim create some degree of obstruction to media flow, providing regulation of the passage of the media through the valve. It is the movement of critical valve trim elements that limit switches are used to indicate or control. The movable valve trim elements commonly connect to a shaft or other linkage extending to the exterior of the valve body. Mounting electric, hydraulic, or pneumatic actuators to the shaft or linkage provides the operator a means to drive the mechanical connection, changing the orientation or position of the valve trim and regulating the media flow. Because of its positive connection to the valve trim, the position of the shaft or linkage is analogous to the trim position and can be used to indicate what is commonly referred to as “valve position”. Limit switches are easily applied to the valve shaft or linkage in a manner that can provide information or direct functional response to certain changes in valve position.

In industrial valve terms, a limit switch is a device containing one or more magnetic or electrical switches, operated by the rotational or linear movement of the valve.

What are basic informational elements that can be relayed to the control system by limit switches? Operators of an industrial process, for reasons of efficiency, safety, or coordination with other process steps, may need answers to the following basic questions about a process control valve:

• Is the valve open? 
• Is the valve closed? 
• Is the valve opening position greater than “X”? 
• Has the valve actuator properly positioned the valve at or beyond a certain position? 
• Has the valve actuator driven the valve mechanism beyond its normal travel limits? 
• Is the actuator functioning or failing? 

Partial or complete answers to these and other questions, in the form of electrical signals relayed by the limit switch, can serve as confirmation that a control system command has been executed. Such a confirmation signal can be used to trigger the start of the next action in a sequence of process steps or any of countless other useful monitoring and control operations.

Applying limit switches to industrial valve applications should include consideration of:

• Information Points – Determine what indications are necessary or useful for the effective control and monitoring of valve operation. What, as an actual or virtual operator, do you want to know about the real time operational status of a valve that is remotely located. Schedule the information points in operational terms, not electrical switch terms. 
• Contacts – Plan and layout a schedule of logical switches that will provide the information the operator needs. You may not need a separate switch for each information point. In some cases, it may be possible to derive needed information by using logical combinations of switches utilized for other discrete functions. 
• Environment – Accommodate the local conditions and hazards where the switch is installed with a properly rated enclosure. 
• Signal – The switch rating for current and voltage must meet or exceed those of the signal being transmitted. 
• Duty Cycle – The cycling frequency must be considered when specifying the type of switch employed. Every switch design has a limited cycle life. Make sure your selection matches the intended operating frequency for the process. 
• Auxiliary Outputs – These are additional contact sets that share the actuation of the primary switch. They are used to transmit additional signals with specifications differing from the primary signal. 
• Other Actuator Accessories – Limit switches are often integrated into an accessory unit with other actuator accessories, most of which are related to valve position. A visual local indication of valve position is a common example. 

Switches and indicators of valve position can usually be provided as part of a complete valve actuation package, provided by the valve manufacturer or a third party. It is recommended that spare contacts be put in place for future use, as incorporating additional contacts as part of the original actuation package incurs comparatively little additional cost.

Employing a properly configured valve automation package, with limit switches delivering valve status or position information to your control system, can yield operational and safety benefits for the life of the unit. Good advice is to consult with a valve automation specialist for effective recommendations on configuring your valve automation accessories to maximize the level of information and control.

General Purpose Valve for Targeted Applications

Industrial Butterfly Valve
Courtesy Adams Valves, Inc.

This is the Adams Valve WEK series industrial butterfly valve. It is a general purpose valve for many applications involving fresh water, seawater, sewage, hydrocarbon and wet gas.

The WEK valves feature low operating torque, compact design, low weight, and good control characteristics. The sealing system is completely integrated within the body of the valve, utilizing a laminated metal and graphite material. Available sizes range from 3" to 24".

Streamlining promotes smooth movement of the disc through its full travel range, without flutter induced by the flow moving around the disc. Sealing is accomplished when the disc rotates to the closed position and seals tightly against the seat which is incorporated into the body. Tight shut off results from the disc pushing into the seal. Valve operation can be manual, via a handwheel, or automated with a range of electric, hydraulic, or pneumatic actuators.

Share your fluid control, valve, and automation challenges with the engineers at CTI Controltech, combining your process and facility knowledge with their product and application expertise to develop the most effective solutions.

Type K Vane Actuator Provides Long Term Solution for Tough Power Plant Application

Rotork K-TORK vane type valve actuators on

bottom ash spray valve control.

Rotork K-TORK vane type valve actuator has solved a difficult flow control application found in many coal-fired power plants – high-pressure bottom ash spray valve control.

High-pressure spray water is used to sluice bottom ash and pyrites from the boiler hopper bottoms and to carry the ash out of the plant. The valves used are typically ANSI Class 300 double-offset high-performance butterfly designs ranging in size from 3” to 12”, automated with double-acting actuators. They cycle from four to ten times per day and discharge to atmospheric pressure, creating a very high pressure drop. The flow media is re-circulated ash water that is abrasive and flows at pressures between 400 and 500 psi.

In many power plants around the world, K-TORK actuators have provided over 10 years of maintenance-free service whilst preserving the life of the valves and valve seats in this arduous duty.

Among the challenges, it is imperative that the valves close fully and with zero leakage in a high pressure drop state. If the valve disc moves even slightly from the seat, the abrasive, high-pressure water will “wire-draw” or cut the butterfly valve seat. Traditionally, rack-and-pinion or scotch-yoke actuators have been used in this application, but “slop” or hysteresis in the rotary-to-linear conversion allows for the pressure in the pipe to move the disc from the seat, often causing premature failure of the valve after a period of only three to twelve months.

The problem becomes more acute when multiple valves are leaking, lowering the available back-pressure at the header, which makes it difficult or impossible to move the ash from the boiler.

When assembled to the valve with a ‘No-Play’ coupling, the K-TORK actuator has zero lost motion, “slop” or hysteresis. The one-piece vane and drive shaft cannot be back-driven and will hold the disc of the valve firmly in place.

Additional challenges include the location of the valves on a manifold at the bottom of the boiler where space is critical and plant air can be poor quality. K-TORK provides a high torque-to-size ratio and the double-opposed lip seal design is forgiving to dirty or contaminated air.

Also, the low-friction performance of K-TORK provides a speed-controlled, smooth valve operation, eliminating the risk of water hammer created by the high pressure drop.

Finally, longer run time between shutdowns demands increased reliability from the equipment in these critical applications. In particular, as the number of plant maintenance personnel has decreased, actuators that reduce maintenance (seal replacement) time and work orders have a direct payback to the owner, especially when valve life can be significantly increased through improved actuator performance.

Share your fluid control and valve actuation challenges with a specialist, combining your process knowledge and experience with their product application expertise to develop effective solutions.

Improved Local Display On Rotork Valve Actuators

IQM Modulating Valve Actuator
Courtesy Rotork

Rotork IQ3 Electric Valve Actuators, a product line handled by CTI Controltech, offer some innovative improvements that provide industrial process operators higher levels of reliability, accessibility, and security than previously available. Among the strong features of this product:

• Advanced Display (detailed in the video below)
• Asset Management
• Bluetooth Communications Interface
• Compact Double-Sealed Enclosure
• Absolute Encoder (on some variants)
• Intelligent Battery Management
• Local Interface
• Secure Local Controls
• Watertight, Dust Tight, Explosion Proof

There is plenty of detail available about all the features of the solidly built IQ3 line of actuators for industrial process valve control. Watch the video and contact a product specialist to get more detail or assess your specific application needs.

Valve Actuator IQ Suffering? This Information Library Can Help.

IQ Series Electric Valve Actuator
Courtesy Rotork

For any component of your industrial process, there is a manufacturer that knows all about how to properly and safely apply, service, maintain, and repair it. The devices we employ to measure and control industrial processes and machines grow increasingly numerous and complex. While this provides operators with greater amounts of useful information, leading to safer and more efficient process operation, the burden on engineers and technicians tasked with coaxing maximum uptime and efficiency from the process grows. Never before has continuing education, even relearning of basic knowledge, been so important. One manufacturer has invested in helping customers and other industrial process control stakeholders keep their operation and maintenance knowledge current.

Rotork, a global manufacturer of industrial valve actuators, maintains extensive online information sources that are accessible to registered users. The instructional and educational assets include online course applications, videos, and other materials to familiarize the user with various aspects of Rotork actuators, their proper application, operation, and maintenance. The large library of "How to" videos provides clear instruction on the safe operation and application of the Rotork actuators, along with step-by-step instruction on how to perform the range of operations involved with obtaining the greatest benefit of ownership. Process engineers, operators, and technicians will all benefit from the assets, enabling them to interface with the products with the confidence that comes from knowledge.

Contact your Rotork distributor for instructions and assistance in gaining free access to the educational tools.

ROTORK IQ Electric Actuator Overview

Here is a quick overview of one of the most popular, and universally specified, electric actuators - the ROTORK IQ Series.

The IQ electric actuator features include ROTORK's unique double-sealed enclosure, ‘non-intrusive' infra-red commissioning, data-logging, predictive maintenance, Bluetooth® communications interface and absolute encoder.

The IQ functionality and reliability is available for valves of virtually every size and description, including multi-turn (rotary), quarter-turn, isolating and modulating, with watertight and hazardous area approvals to all internationally recognized standards.

Electrically Actuated Ball Valve Operation with Limit Switches

This video demonstrates the operation a small (Worcester) motor operated ball valve also known as an “MOV”. Also known as an “electric actuator”, motor operators come in a wide variety of sizes and styles. Some electric actuators are intended for quarter-turn valves (such as ball and butterfly valves), while others are designed to operate linear valves (such as gate and globe valves).

The MOV / electric actuator consists of an electric motor with the gearbox assembly which rotates the shaft of the valve. Most MOVs operate at 120, 240 or 480 volt, single or three phase. Basic features include adjustable limit switches to limit valve travel and to notify valve status, directional settings, analog inputs to allow for precise control, analog outputs to provide a feedback signal and digital communications. MOV enclosures can be either NEMA 4, NEMA 4X and NEMA 7 and are available in a wide range of torque outputs to match the valve it is operating.

Heavy Duty Scotch Yoke Pneumatic Valve Actuator

Scotch yoke refers to a sliding linear mechanism that provides a reciprocating motion. One of the most common uses for scotch yokes are pneumatic valve actuators.

Scotch yoke mechanism
(courtesy of Wikipedia)

Scotch yoke valve actuators are designed to provide higher torque output for larger industrial valves. They typically have large pistons and air cylinders that provide the linear force required to open and close large quarter turn valves (ball, butterfly, plug).

Scotch yoke pneumatic actuators installed
in sea terminal
(courtesy of Rotork)

Scotch yoke actuators can be energized by either compressed gases, or hydraulic fluids. Here are some images of scotch yoke actuators in use:

Large spring return scotch yoke actuator
(courtesy of Rotork)

An Industrial Electric Actuator Designed to Keep the Water and Dust Out

The Rotork IQ3 electric actuator includes a double o-ring seal to keep the internal parts sealed away from water and dust should the electrical conduit seals fail.

The Rotork IQ3 also includes these advanced features:

• New intuitive user interface
• Advanced dual stacked display with configurable datalogger functionality
• Toughened glass screen plus optional environmental shield
• Setting tool with secured Bluetooth® connection
• High reliability, solid-state controls
• Reduced internal wiring and connections
• Simplified torque sensor
• Simple and robust absolute position sensor with high reliability and accuracy
• New thrust base design
• Separable gearbox/thrust base across the range
• Advanced real-time status reporting

Watch this video to see the how the IQ3 double o-ring seal keeps out water and dust.

Rack and Pinion Pneumatic Actuator Basics

A rack and pinion gear.
(Courtesy of  Wikipedia)

Rack & Pinion actuators are designed for operating quarter-turn valves such as butterfly, plug, and ball valves or for actuating industrial or commercial dampers.

The rotational movement of a rack and pinion actuator is accomplished via linear motion and two gears. A circular gear, referred to a “pinion” engages the teeth of a linear gear “bar” referred to as the “rack”.

In a pneumatic actuator, pistons are attached to the rack. As air or spring power is applied the to piston, the rack is “pushed” inward or “pulled” outward. This dual direction linear movement is transferred to the rotary pinion gear providing bi-directional rotation.