The Future of Industrial Valve Automation

Rapid technological innovations will push industrial valve automation to new heights over the next five years. Here are some of the key trends that will drive progress in industrial valve automation and process control:

Increased Integration of IIoT and AI

The Industrial Internet of Things (IIoT) has enabled wireless networking to connect industrial valves and actuators to centralized control systems. IIoT connectivity will become ubiquitous in the future, allowing industrial facilities to collect vast troves of operational data from automated valves. Facilities can then analyze this data using artificial intelligence (AI) and machine learning algorithms to optimize valve performance, predict maintenance needs, and fine-tune process control logic.  

AI integration will lead to self-optimizing and self-healing valve systems that can automatically adjust parameters, detect anomalies, and take corrective actions with minimal human intervention. Smart valve positioners enabled by edge AI computing will make real-time adjustments to ensure precise valve positioning. AI-powered industrial valve automation will enhance process reliability, reduce unplanned downtime, and boost operational efficiency.

Advanced Valve Condition Monitoring  

Many industrial facilities rely on manual inspections and scheduled maintenance to service valves, actuators, and related equipment. However, over the next five years, comprehensive online condition monitoring systems leveraging IIoT connectivity and smart sensors will become the norm. These valve monitoring systems will continuously track performance metrics like valve position, pneumatic pressure, temperatures, vibration signatures, and more.

Sophisticated analytics will allow maintenance teams to accurately predict valve failures based on degrading conditions before they occur. Rather than reacting to unexpected breakdowns, industrial plants will transition to a predictive maintenance model for valve assets. This approach will minimize unplanned shutdowns, reduce maintenance costs through optimized work schedules, and extend the operating life of valve equipment.

Adoption of Wireless Systems

Installing miles of wired communications infrastructure has traditionally been a significant cost and complexity for industrial valve automation projects. In the coming years, reliable and secure wireless technologies like WirelessHART, ISA100, and 5G will see increased adoption for connecting automated valve assemblies to control systems. Wireless valve automation will slash installation costs and enable flexible retrofitting of existing facilities.

Moreover, battery-powered industrial wireless valve controllers could provide autonomous operations without a grid power source in remote locations. For control valve assemblies in hazardous areas, wireless connectivity eliminates safety risks associated with running wired conduits, enhancing worker safety.  

Continued Push Towards All-Electric Actuators

Pneumatic valve actuators powered by compressed air have long been the industry standard. However, their inherent limitations, such as air leaks, freeze-ups, and maintenance requirements, will drive more industrial plants to adopt all-electric actuators over the next five years. Modern electric actuators offer high reliability, precision, efficiency, and easier integration with digital valve controllers.

Conclusion

As industrial valve automation continues its accelerated evolution through emerging technologies, process manufacturing across numerous sectors will benefit from tighter control, improved safety, increased uptime, and optimized efficiency. The coming years will reshape how valve-automated processes get designed, operated, and maintained using the latest digital innovations.

Mead O'Brien
https://meadobrien.com
(800) 874-9655

White Paper :Ten Reasons to Consider Brushless DCV Motors in Electric Valve Actuators

This paper, courtesy of Flowserve Limitorque, aims to investigate the most recent advancements in these motors, consider alternatives, and discuss how to make an informed decision about when and where to use BLDC motor technologies.

Brushless DC motors are synchronous motors powered by a direct current source via an electric controller rather than the brush/commutator mechanism used in brushed DC motors. The electric controller, an integrated inverter/switching power supply, generates an alternating current signal that drives the rotor. Electronically commutated motors, ECMs, or EC motors are other names for them.

Brushless DC electric (BLDC) motors have been around for nearly 50 years, but their use for intelligent actuation is relatively new. Their adaptation is critical to the improvement of process control and plant safety systems.

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DOWNLOAD THE WHITE PAPER HERE

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Leading Edge Electric Actuators - The Limitorque MXb

The Limitorque MXb electric actuator performs across a broad range of challenging applications where reliability is critical, including oil and gas; commercial power; chemical; fresh and wastewater; and general industries.

Improved reliability

The actuator's design isolates critical components, protecting them from electrical shock and interference, typical in extreme environments. High-quality materials extend actuator service life, operating ranges, and mean time between failure.

Enhanced user experience

An updated user interface coupled with a simplified, intuitive menu structure and larger, high-resolution LCD screen makes navigation easy and enables 50% faster commissioning, set-up, and operation. Users of any skill level can configure the actuator through various pre-configured or customization options for quick and error-free set-up and operation. A larger, higher-resolution LCD with a built-in ambient light sensor offers eight times the previous display's resolution to extend viewing distances up to 30 feet. Real-time torque graphs, alarm and event logs, and other data are accessible in higher-quality resolution.

Advanced diagnostics and analytics

The MXb electric actuator's next-generation diagnostics and analytics capabilities help operators monitor and track its performance and quickly respond to upset conditions. The MXb actuator has 500 times the previous MX model's memory capacity, allowing increased data capture and storage for higher degrees of process monitoring, data logging, and information feedback. Additionally, a real-time clock enables data log time stamping to support asset management functions and lifecycle analysis.

Simplified maintenance

A new electric connector design removes the need for brackets and hold-downs, making maintenance more straightforward and faster. And the enhanced connector design ensures robust connectivity throughout the rated seismic and vibration envelope.

For more information about the Limitorque MXb contact Mead O'Brien by calling (800) 892-2769 or visiting their website at https://meadobrien.com. 

Pneumatic Valve Actuators

Actuated valve with pneumatic
scotch yoke actuator (Metso Neles)

Pneumatic valve actuators are used in extreme conditions in many industries such as oil and gas, chemical, water and wastewater, bulk storage, pulp & paper, and power generation. These devices are used in a multitude of valve control processes for regulation (or cessation) of flow, and / or controlling pressure and level.  Due to their reliability and simplicity, pneumatic actuators are one of the most popular types of actuators used in industry today.

Pneumatic valve actuators work by conversion of air pressure into motion. The device applies a force of air to a diaphragm, rotary vane, or piston that is attached to the actuator shaft, which is then mechanically connected to the stem of the valve or damper. Depending on the type, pneumatic actuators produce either linear or rotary motion. 

ACTUATOR ACTION - SPRING RETURN OR DOUBLE ACTING

Spring Return — Pneumatic actuators with spring return design have air supplied from one side. The spring on the opposite side is responsible for the motion. With this design, air compression moves the opens or shuts the valves while the spring is responsible for the opposite motion. 

Diaphragm actuator
(Metso Neles)

Double Acting  — Double acting actuators have air fed on both sides of a piston. The pressure on one side is higher as compared to the other that results in the required in movement. Air is used to open and close the valves.  

PNEUMATIC ACTUATOR DESIGNS

Diaphragm Actuators — Diaphragm actuators work by applying pressure to a thin membrane or diaphragm.  

Piston Actuators — Piston actuators apply compress air to a piston that is within a cylinder. Air is fed into a chamber that moves the piston in one direction. The piston moves in the opposite direction when air pressure is removed (spring assisted) or directed to the other side (double acting). 

Rack and Pinion — Rack and pinion actuators produce rotation by applying pressure to pistons with gears that turn a pinion gear. Rack and pinion actuators can be spring return or double acting. They are valued because of their compact size and versatility.

Rack and pinion actuator
(Metso Jamesbury)

Scotch Yoke — A scotch-yoke actuator contains a piston, yoke, connecting shaft, and rotary pin. They can be direct acting or spring return. They are capable of providing very high torque outputs and are generally used on larger valves. Scotch yoke actuators can be powered by air or process gas.

Rotary Vane —Vane actuators use a mechanical vane, connected to a shaft, that separates a circular shaped body in two "clamshell" halves. The vane moves in response to the differential pressure inside the actuator body, turning the shaft clockwise or counter-clockwise in response to the pressure differential. External springs units are available for spring return models.

Scotch yoke actuator (Metso Neles)

BENEFITS OF PNEUMATIC ACTUATORS

The use of compressed air (typically found in all industrial facilities) as the power source is the prime advantage for the use of pneumatic actuators. Additionally, pneumatic actuators have an advantage in suitability for different environments and can be used in extremes temperatures. They are preferred over electrical actuators in explosive, flammable and other hazardous areas because they do not require electricity (a possible ignition source) to operate. They do not create electrical fields or electrical noise since there is no electrical motor. Pneumatic valve actuators are faster opening and closing compared to their electric counterparts. Finally, they are low cost, lightweight, durable, require little maintenance (depending on quality) and there are a myriad of positioning controls, speed controls, and communications devices available for tailoring the actuator to the application.

DRAWBACKS OF PNEUMATIC ACTUATORS

While compressed air is the main reason for using pneumatic actuators, it can also be considered a drawback. For instance, pneumatic actuators can perform poorly when the air supply source is located at a distance, resulting in lag and slow response. Another drawback of pneumatic actuators is the additional cost for the compressed air system due to the requirement of dust filters and moisture removing dryers. These are required to ensure clean air is fed into the system.

APPLYING PNEUMATIC ACTUATORS

There are many aspects to the proper, safe, and efficient application of pneumatic actuators to valves and dampers. The sizing the power (torque) output being paramount. All valves and dampers have unique torque requirements. You must consider a threshold force for opening (breakaway), as the valve continues to move to its open or closed position, and then for seating. Matching the actuators to the valve type, and operating conditions is critical. Published torque curves must be reviewed and understood. Too little torque and the valve will not respond. Too much torque increases cost and can damage the valve. Spring return adds to this complexity. Considering all this, it is strongly suggested you always discuss any valve actuation requirement with an experience applications expert. They will ensure the proper, safe, and cost effective mating of pneumatic actuator to valve or damper.

Mead O'Brien: Problem Solver, Innovator, and Best Total Cost Provider

Mead O’Brien specializes in valves & valve automation, steam & hot water products and systems, instrumentation products, skid designs, field services, surveys, assessments, and consulting. The extensive product and application knowledge possessed by the Mead O'Brien sales force projects to all or part of ten states in the Midwest which includes Missouri, Kansas, Nebraska, Iowa, Oklahoma, Arkansas, Texas Panhandle, Southern Illinois, Western Kentucky, and Southwest Indiana.

Expert Valve Automation and Valve Communications Services

With expertise in pneumatic rack and pinion and scotch-yoke, as well as electric quarter-turn and linear, Mead O'Brien has the experience and facilities to deliver a well engineered automated valve package.

Call (800) 892-2769 or visit https://meadobrien.com for more information on any valve automation requirement.

Mead O'Brien: Experts in Valves, Valve Automation, Steam & Hot Water Systems, Process Instruments

Mead O’Brien specializes in valves & valve automation, steam & hot water products and systems, instrumentation products, skid designs, field services, surveys, assessments, and consulting.

Product Focus:

• Valves, valve automation and control
• Steam and hot water products and systems
• Instrumentation and controls

For more information, visit http://www.meadobrien.com or call  (800) 892-2769.

Please pardon our little shameless self-promotion. Thanks for watching this short video highlighting Mead O'Brien products.

Industrial Valve Actuator Basics

Electric actuator (Limitorque)

Actuators are devices which supply the force and motion to open and close valves. They can be manually, pneumatically, hydraulically, or electrically operated. In common industrial usage, the term actuator generally refers to a device which employs a non-human power source and can respond to a controlling signal. Handles and wheels, technically manual actuators, are not usually referred to as actuators. They do not provide the automation component characteristic of powered units.

The primary function of a valve actuator is to set and hold the valve position in response to a process control signal. Actuator operation is related to the valve on which it is installed, not the process regulated by the valve. Thus a general purpose actuator may be used across a broad range of applications.

Pneumatic actuator (Metso Neles)

In a control loop, the controller has an input signal parameter, registered from the process, and compares it to a desired setpoint parameter. The controller adjusts its output to eliminate the difference between the process setpoint and process measured condition. The output signal then drives some control element, in this case the actuator, so that the error between setpoint and actual conditions is reduced. The output signal from the controller serves as the input signal to the actuator, resulting in a repositioning of the valve trim to increase or decrease the fluid flow through the valve.

An actuator must provide sufficient force to open and close its companion valve. The size or power of the actuator must match the operating and torque requirements of the companion valve. After an evaluation is done for the specific application, it may be found that other things must be accommodated by the actuator, such as dynamic fluid properties of the process or the seating and unseating properties of the valve. It is important that each specific application be evaluated to develop a carefully matched valve and actuator for the process.

Hydraulic and electric actuators are readily available in multi-turn and quarter-turn configurations. Pneumatic actuators are generally one of two types applied to quarter-turn valves: scotch-yoke and rack and pinion. A third type of pneumatic actuator, the vane actuator, is also available.

For converting input power into torque, electric actuators use motors and gear boxes while pneumatic actuators use air cylinders. Depending on torque and force required by the valve, the motor horsepower, gearing, and size of pneumatic cylinder may change.

Linear pneumatic actuator (Neles)

There are almost countless valve actuator variants available in the industrial marketplace. Many are tailored for very narrow application ranges, while others are more generally applied. Special designs can offer more complex operating characteristics. Ultimately, when applying actuators to any type of device, consultation with an application specialist is recommended to help establish and attain proper performance, safety and cost goals, as well as evaluation and matching of the proper actuator to the valve operation requirements. Share your fluid process control requirements with a specialist in valve automation, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Industrial Valve Automation, Service and Repair

From quarter-turn ball, butterfly, or plug valves, to linear gate and globe valves, Mead O'Brien can handle the most challenging actuation design. Options and accessories such as valve communications, limit switches, fail-safe devices, and solenoid valves are no problem.

With decades of expertise in rack and pinion and scotch-yoke actuators, as well as electric quarter-turn and linear actuators, Mead O'Brien has the experience and facilities to deliver a well engineered automated valve package. Visit www.meadobrien.com.

Understanding Industrial Valve Actuators

Automated Pneumatic
Ball Valve (Jamesbury)

Valves are essential to industries which constitute the backbone of the modern world. The prevalence of valves in engineering, mechanics, and science demands that each individual valve performs to a certain standard. Just as the valve itself is a key component of a larger system, the valve actuator is as important to the valve as the valve is to the industry in which it functions. Actuators are powered mechanisms that position valves between open and closed states; the actuators are controllable either by manual control or as part of an automated control loop, where the actuator responds to a remote control signal. Depending on the valve and actuator combination, valves of different types can be closed, fully open, or somewhere in-between. Current actuation technology allows for remote indication of valve position, as well as other diagnostic and operational information. Regardless of its source of power, be it electric, hydraulic, pneumatic, or another, all actuators produce either linear or rotary motion under the command of a control source.

Thanks to actuators, multiple valves can be controlled in a process system in a coordinated fashion; imagine if, in a large industrial environment, engineers had to physically adjust every valve via a hand wheel or lever! While that manual arrangement may create jobs, it is, unfortunately, completely impractical from a logistical and economic perspective. Actuators enable automation to be applied to valve operation.

Pneumatic actuator
(Jamesbury Quadra-Powr) 

Pneumatic actuators utilize air pressure as the motive force which changes the position of a valve. Pressurized-liquid reliant devices are known as hydraulic actuators. Electric actuators, either motor driven or solenoid operated, rely on electric power to drive the valve trim into position. With controllers constantly monitoring a process, evaluating inputs, changes in valve position can be remotely controlled to provide the needed response to maintain the desired process condition.

Manual operation and regulation of valves is becoming less prevalent as automation continues to gain traction throughout every industry. Valve actuators serve as the interface between the control intelligence and the physical movement of the valve. The timeliness and automation advantages of the valve actuators also serve as an immense help in risk mitigation, where, as long as the system is functioning correctly, critical calamities in either environmental conditions or to a facility can be pre-empted and quickly prevented. Generally speaking, manual actuators rely on hand operation of levers, gears, or wheels, but valves which are frequently changed (or which exist in remote areas) benefit from an automatic actuator with an external power source for a myriad of practical reasons, most pressingly being located in an area mostly impractical for manual operation or complicated by hazardous conditions.

Electric Actuator
(Limitorque)

Thanks to their versatility and stratified uses, actuators serve as industrial keystones to, arguably, one of the most important control elements of industries around the world. Just as industries are the backbones of societies, valves are key building blocks to industrial processes, with actuators as an invaluable device ensuring both safe and precise operation.

Selecting the Right Valve Automation Partner for the Power Industry

Electrically automated gate valve
in generating facility.

Having knowledgeable, experienced and skilled vendor-partners is crucial in mitigating safety, environmental, and health risks, as well as meeting power generation facility construction and production goals. Partnering with the right valve automation company means that you will have industry experts there to ensure the success of your project, meeting your budgetary and performance goals, and passing critical know-how along to your staff.

But what should you look for in a valve automation partner?

Understanding and Meeting Expectations
Your valve automation partner needs to understand your industry, the application, and the upstream and downstream processes affected by the automated system being installed. Your partner must have a full understanding of all types of valve automation, including pneumatic, hydraulic, electro-hydraulic, and electric actuation. A full understanding of the morass of technical and administrative requirements is critical. These include a knowledge of applicable codes, industry standards, environmental concerns, maintenance requirements, back-up systems, and emergency processes. A strong candidate will consider all of these factors for every power plant valve automation job.

Engineering, Experience, and Precision
Qualified engineering staff and experience are critically important factors in selecting your valve automation partner. A qualified partner should have engineering staff with decades, not just years, of experience in applying, specifying, designing, and fabricating automated valve systems for the power industry. Additional experience in other industry segments is a plus, but a working history and a proven, successful track record in power plant automation is mandatory. All production technicians should be factory trained with valid certification. Whether a 1/2” ball valve with simple electric actuator, or 48” valve gate with extensive controls, your valve automation partner needs to reliably and consistently ensure conformance to specifications.

Involvement
Your valve automation partner needs to remain involved in every step of the process - from specifying, quoting, fabrication, delivery, installation, and training. The best valve automators stand by the customer after the automated valve systems are shipped. They see the project through to completion, paying great attention to detail. They generally obsess over the smallest details. For instance, a critical area is actuator-to-valve adaption design and configuration and a good candidate will pay very close attention to that piece. Good valve automation partners create and provision high quality drawings and wiring diagrams. They carefully ensure all requested settings and configuration meets specification and is completed. Finally, they maniacally Q.C. the completed automated valve though in-depth cycle testing before shipping. A good valve automation partner truly understands that this investment in detail upfront, eliminates costly downstream errors and mistakes.

Documentation and Tagging
Your partner should provide very detailed documentation for each automated package. Documentation packages should be very detailed and include valve Cv, actuator sizing calculations, material selection criterion, ISA data-sheets, dimensional drawings, operational testing data, seat leak test data, packing leakage data, and switch setting verification. Your valve automation partner should standardly provide valve packages tagged with stainless steel stamped serial numbers that provide traceability back to original components, fabrication, and testing.

Facilities
Your valve automation partner should have in-house capabilities for lifting, moving, testing, and storing large valve assemblies. The facility needs adequate pneumatic and electrical service to power any system they build. The space and ability to move large valves with lifts, hoists, and jacks is important. Storage space for sub-assemblies and finished goods, high pressure leak testing stations, seat leak testing stations. In-house CAD systems and on-premise machine shops provide an environment for better quality control and communication. Close proximity between engineers, designers, and technicians supports efficient communication and full understanding of customer needs. An on-site training room, with all required electrical and pneumatic testing rigs should be available. Finally, large docking facilities and easy access to major highways minimizes transportation issues and lowers cost.

Training

Valve automation training facility
(courtesy of Mead O'Brien)

Your plant maintenance crews must have 100% familiarity with the operation, maintenance, and troubleshooting of your new valve systems. Your valve automation partner must have the capability to provide practical, and hands-on, training on all facets of valve automation. Programs must be customizable to customer needs and special situations.

By doing your due diligence, and thoroughly evaluating a prospective valve automation partner, you are establishing a framework of confidence and trust that minimizes risk and provides peace of mind that your critically important power plant valve systems will provide safe, efficient, and reliable performance for years to come.

Don’t Overlook the Value of Valve Automation Professionals on Your Next Valve Project

Sales and Engineering Professionals are there to assist
and save you time and money.

Local distributors and representatives who sell industrial valves, actuators and controls also provide services and equipment that will save you time, money, and help you achieve a better outcome for the entire project.

Projects requiring engineered valve systems are best completed and accomplished through the proper selection and application of the valves, actuators, positioners, limit switches and other associated components. A great resource exists, ready to provide a high level of technical knowledge and assistance, that can be easily tapped to help you with your project - the valve automation sales professional.


Consider a few elements the valve automation professional brings to your project:

Product Knowledge: Valve automation professionals are current on product offerings, proper application technique, and product capabilities. They also posses  information on future product obsolescence and upcoming new designs. This type of information is not generally accessible to the public via the Internet.

Experience: As a project engineer, you may be treading on new ground regarding some aspects of your current valve system design assignment. There can be real benefit in connecting to an experienced and highly knowledgable source, with past exposure to your current challenges.

Access: Through a valve automation professional, you may be able to establish a connection to “behind the scenes” manufacturer contacts with essential information not publicly available. The rep knows people at the factories, a well as at other valve related companies, who can provide quick and accurate answers to your valve automation related questions.

Of course, any valve actuation or automation solution proposed are likely to be based upon the products sold by the representative. That is where considering and evaluating the benefits of any solution becomes part of achieving the best project outcome.

Develop a professional, mutually beneficial relationship with a local valve automation professional to make your design job go after, more efficiently, and more cost effective. Their success is tied to your success, and they are eager to help you.

For assistance with any industrial valve automation requirement, contact Mead O'Brien at (800) 892-2769 or visit http://www.meadobrien.com.

A Look Inside the Neles NDX Intelligent Valve Controller

Neles intelligent valve controller 

Metso’s Neles NDX is the next generation intelligent valve controller working on all single acting control valves and in all industry areas. It guarantees end product quality in all operating conditions with incomparable performance, unique diagnostics, and years of reliable service.

Operating Principle:

The NDX is a 4–20 mA powered micro-controller based intelligent valve controller. The device contains a local user interface enabling configuration and operation without opening the device cover. Configuration and operation can also be made remotely by PC with asset management software connected to the control loop.

After connections of electric signal and pneumatic supply, the micro-controller (μC) continuously reads measurements:

Click for larger view

• Input signal 
• Valve position with contactless sensor (α), 
• Actuator pressure (I) 
• Supply pressure (S) 
• Device temperature

Advanced self­-diagnostics guarantee that all measurements operate correctly.

Powerful micro-controller calculates a control signal for I/P converter (prestage). I/P converter controls the operating pressure to the pneumatic relay (output stage). Pneumatic relay moves and actuator pressure changes accordingly. The changing actuator pressure moves the control valve. The position sensor measures the valve movement. The control algorithm modulates the I/P converter control signal until the control valve position matches the input signal.

The video below demonstrates the NDX's operation. Below the video is the complete installation, maintenance and operation manual for your convenience.

Neles NDX Intelligent Valve Positioner from Mead O'Brien, Inc.

The Application of Limit Switches on Automated Industrial Valves

Limit switch with position indicator.

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.

Employed in a wide range of industrial applications and operating conditions, limit switches

are known for their ease of installation, simple design, ruggedness, and reliability. 

Automated valve assembly
including actuator and
limit switch.

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.

Product Update - New Valve Actuator Series From Limitorque

New Limitorque CEA Series Valve Actuator
Courtesy Flowserve Corp.

Industrial process control encompasses a broad range of fluid handling operations. A significant part of fluid control is accomplished by valves, many of which are operated automatically through the use of actuators. Actuators are mounted on valves in place of, or in addition to, a handwheel, lever, or other manual means of opening and closing the valve. With an actuator installed, a control signal can be transmitted from a remote source to the actuator, commanding a change in valve position, and the actuator will respond by converting some form of connected energy into mechanical motion that positions the valve accordingly.

Modern actuators are increasingly endowed with functions that provide information to the process operator, closing the loop with feedback that confirms the valve position, suitability of the energy supply to the actuator, and a range of other specialized data points.

An eternal desire of all process operators is a reduction in whatever level of maintenance that is currently required to keep everything operating. Maintenance is costly and time consuming, a set of many specialized tasks, each with a probability of not being completed properly.

Flowserve Corporation, under their well known Limitorque brand, has designed and launched a new series of electric actuators, the CEA Series, that provide real benefits for operation and maintenance in light-to-medium duty applications. Some of the highlights....

• Auto calibration and a user-friendly HMI provide optimized commissioning. Standard diagnostics include torque monitoring and actuator temperature, with early warning detection of undesirable conditions and an alarm output.
• Application specific brushless DC motors and worm gear drives reduce downtime. Tests have demonstrated reliability of up to 250,000 cycles. Modulating service can provide 1800 starts per hour with 0.1% position accuracy.
• Suitable for applications with rotary duty requirements of 90 and 180 degrees, as well as multi-turn duty to 20 turns.
• Available through a network of professional industrial process control distributors, with application assistance and product expertise.
• CEA is fully qualified to NEMA Type 4, 4X and6, IP66/68 Class 1, Div 1 and 2, Gps B,C,D (CSA,FM) and ATEX II 2G Ex d IIB +H2 T4: IECEx II 2G Ex d IIB +H2 T4.

The CEA actuator is available in seven sizes and five variants, serving torque requirements up to 15,000 in-lbs (1695 Nm). Contact a product specialist to find out more about this new product and discuss your potential applications.

Limitorque CEA Actuator Data Sheet from Mead O'Brien, Inc.

StoneL Axiom Limit Switch as Your Valve Automation Plant Standard

This video presents the StoneL Axiom limit switch as a strong plant standardization contender for all your valve automation needs.

The Axiom not only has all components incorporated integrally, it is a space efficient design utilizing the most flexible components for most applications: 20-125 VAC or DC monitoring feedback and solenoid control; 5-way, 2-position solenoid control with selection for either direct acting or spring return actuators in two Cv flow capacities for a wide range of actuators; bus communication modules and low power solenoid valves, re-breather solenoid functions, and manual override, all in a very rugged package.

For more information, contact:
Mead O'Brien
(800) 892-2769
www.meadobrien.com