Valves Blog (no longer active)

Fail-Safe Electric Actuators for Quarter-Turn Valves

Jim Cahill — Fri, 31 Jan 2020 22:35:19 GMT

For many applications, such as emergency shutdowns (ESD), on-off quarter valves with electric actuators are the best fit. In the event of loss of power, some type of fail-safe mechanism may be required to bring the valve into an open or closed position as required by the process. These applications are typically found in the oil & gas, power, chemical, HVAC, and water & wastewater industries.

The Bettis RTS FQ Fail-Safe Quarter-turn Electric Actuator use energy stored in mechanical springs to position the valve in fail-safe close or open direction. The fail-safe actuators provide a reliable and repeatable mechanism for fail-safe actions without dependency on battery backup or the repeated re-charge cycles of a super capacitor. The mechanical fail-safe spring action enables safe operating mechanism for emergency shutdowns.

In this 16:19 YouTube video, Bettis RTS Fail-Safe Quarter Turn Electric Actuator Basic Technical Overview, Emerson’s Aaron Roepke provides a product overview and demonstration of certain configuration and setup steps including user interface rotation, user interface navigation, variable speed adjustment, and mechanical fail-safe speed adjustment.

Aaron opens pointing to and explaining the components in the electric actuator. He demonstrates how to rotate the user interface based on how the actuator is mounted to the valve. He then provides an overview of the control unit. Finally, Aaron shows how to adjust the speed of the fail-safe action in the actuator as required by the application. Note: these hyperlinks go to separate videos showing just these portions from the embedded video above.

For more on these fail-safe electric actuators, visit the Bettis RTS FQ Fail-Safe Quarter-turn Electric Actuator page on Emerson.com. You can also connect and interact with other valve actuator experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

The post Fail-Safe Electric Actuators for Quarter-Turn Valves appeared first on the Emerson Automation Experts blog.

Self-Contained Hydraulic Emergency Shutdown System

Jim Cahill — Tue, 21 Jan 2020 20:49:21 GMT

Sergio Vaz Lopes

A safety instrumented function (SIF) in a safety instrumented system (SIS) contains a sensor, logic solver and final element. All must function properly in the event of a safety demand to take the process into a safe state in coordination with other SIFs.

The final element consists of several parts including the isolation valve, actuator, pressure pilots, test valves and other components as required by the application. In this quick, 2:17 video, Introduction to Bettis PressureGuard Hydraulic Emergency Shutdown System, Emerson’s Sergio Vaz Lopes describes the elements of this self-contained, hydraulic Emergency Shutdown (ESD) system.

This ESD system provides reliable valve shutdown capability when an external power source is either not available or not dependable. These can be used with rotary hydraulic operators to provide a fail-safe system for use with ball, plug and other quarter-turn valves, as well as non-API 6A linear operated valves.

These PressureGuard ESD systems typically include a self-contained hydraulic module, a hydraulic actuator and application-specific shutdown triggers such as high- and/or low-pressure pilots, solenoid valves, and a temperature sensing fusible plug.

Examples of applications where these ESD systems are a good fit include oil & gas production wellheads, custody transfer points, and other SIFs where automatic valve emergency shutdown is required and external power such as compressed air, natural gas, or electricity is not readily available.

Under normal conditions, the PressureGuard system maintains the valve in its operational position by resisting the spring force with hydraulic fluid pressure. In a safety demand event requiring automatic ESD valve operation, the PressureGuard uses a control component to shift hydraulic fluid from the valve operator to an internal reservoir. Without fluid pressure, the compressed spring in the operator moves the valve to its shutdown position.

Visit the Bettis PressureGuard Hydraulic Emergency Shutdown System page as well as the Actuators section on Emerson.com for more on this and other valve actuator technologies to meet your requirements. You can also connect and interact with other final element experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

The post Self-Contained Hydraulic Emergency Shutdown System appeared first on the Emerson Automation Experts blog.

Adding Experts in Valve Condition Monitoring

Jim Cahill — Tue, 14 Jan 2020 21:18:21 GMT

Fabrice Hoenig

Data available in manufacturing and production facilities is growing faster than people can process. In a Process Industry Informer article, How Valve Condition Monitoring Reduces Plant Downtime, Emerson’s Fabrice Hoenig highlights this challenge:

The vast amount of data that is generated about equipment condition and performance offers a great opportunity to engineers, but it can be overwhelming to collect and analyse, especially in a time of decreasing workforces and expertise.

Fabrice notes the improvement opportunity:

…ARC Advisory Group estimates that around $20bn, or 5% of annual production, is lost as a result of this downtime every year… around 80% of those losses are preventable.

Given this opportunity, effectively distilling and analyzing this wealth of data can drive business performance improvements. He explains that valves:

…are a critical final control component for any flow-based process and play a key role in overall availability and variability. This makes valves an essential asset requiring inclusion in any predictive maintenance-enabling condition monitoring solution.

While collecting the condition-based data is important, having experts analyze and provide actionable recommendations is what drives improvements. This expertise is often lacking on site or within the company’s organization.

Expertise and technology, delivered by an expert service provider can help close the consumption gap between the functionality that is available, and the functionality that is actually utilised.

Fabrice shares benefits in implementing valve condition monitoring. One example includes the

…insights generated from monitoring supports more efficient shutdowns, turnarounds or outages (STOs), which can amplify savings. For example, it costs about $5,000 on average to pull a valve, yet in an STO where valves are maintained to a schedule rather than using data-driven decisions, around 30% of the pulled valves are found to not need repairs.

Read the article for more on the value in identifying issues earlier, how valve condition monitoring works, and how to implement an effective valve condition monitoring solution.

Learn more about the real-time, non-intrusive Valve Condition Monitoring technology and expertise solution on Emerson.com. You can also connect and interact with other valve experts in the Valves, Regulators & Actuators group in the Emerson Exchange 365 community.

The post Adding Experts in Valve Condition Monitoring appeared first on the Emerson Automation Experts blog.

Digital Valve Services for Improved Operational Performance

Jim Cahill — Fri, 10 Jan 2020 20:26:48 GMT

For process manufacturers & producers, the performance of final control elements including valves, actuators and regulators has a major impact on their efficiency, reliability and variability. Knowing how these final control elements are performing and when they need attention can improve overall operational performance.

This short 3-minute video, Digital Valve Services, highlights a portfolio of tools that provide operational data that is supplemented by OEM expert support to help keep valves operating as expected.

The video opens showing conditions that can affect valve performance such as sticking, leaking, flashing, cavitation and high friction conditions. Traditionally these problems were identified through periodic manual inspection. However, a shrinking workforce and retiring in-house technical expertise make these inspections tedious and costly.

Emerson’s Digital Valve Services provides site data collection tools & safety procedures with the support of OEM valve experts to analyze and provide actionable information to maintain performance of the valves with efficiency and effectiveness. The tools streamline service engagements, provide equipment performance data, highlight safety practices and enable data collection to feed decision making.

One example of these digital tools include RFID-based Asset Management Tags, to accurately and safely collect & process construction and service data about the valve assembly.

For maintaining optimal valve performance, the Valve Condition Monitoring Service, a Connected Service offering within the Plantweb digital ecosystem, enables early identification of issues through non-intrusive diagnostics. These diagnostics are analyzed by Emerson valve experts who recommend solutions to restore optimal performance. For complex problem-solving situations, Remote Assistance via augmented reality technology enables OEM support directly to the technicians on site.

We’ll explore Asset Management Tags and Valve Condition Monitoring in more detail in future posts.

For more on ways to improve operational performance through optimal valve operation, visit the Digital Valve Services page on Emerson.com. You can also connect and interact with other final control experts in the Valves, Actuators & Regulators group on Emerson Exchange 365.

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Understanding Functional Safety Concepts and Final Element Suitability

Jim Cahill — Wed, 08 Jan 2020 20:05:41 GMT

Riyaz Ali

The world of functional safety has its own tribal language and acronyms, e.g. safety instrumented systems (SISs), safety instrumented functions (SIFs), logic solvers, final elements (FEs), safety integrity level (SIL), probability of failure on demand (PFD), etc.

In a Hydrocarbon Engineering article, Keep in the Safety Loop, Emerson’s Riyaz Ali does an excellent job of defining and demystifying these phrases and concepts.

He opens describing the differences between basic process control systems (BPCSs) and safety instrumented systems:

A BCPS, consisting of a transmitter, controller and control valve, operates under dynamic conditions, with outputs constantly being adjusted for process control. In terms of FCE [final control element] use, it is a high-demand system.

In contrast, a SIS is typically passive, with low demand, and takes action only when a dangerous condition is detected. It consists of a sensor, logic solver and FE…

Riyaz described the challenge with a valve being the low-demand, final element in the safety instrumented function, a.k.a. safety loop:

Without any mechanical movement, unreliability inherently increases, and SIS valves are prone to sticking due to long static dormant status.

This sticking or other issues affecting the valve’s ability to change states from open-to-close or close-to-open is a failure on demand. The safety integrity level:

…specifies the safety integrity requirements of the SIF and is a quantifiable measurement of risk, used as a way to establish safety performance targets of SIS systems.

SIL:

…can be expressed in terms of probability of failure on demand (PFD), a value that indicates the probability of a system failing to respond to a demand.

Riyaz highlights two types of failures—physical and functional. Physical failures can be predicted based on operating histories and experiences. Functional failures such as programming bugs cannot be accurately predicted.

The IEC 61511 functional safety lifecycle standard [hyperlink added for additional information]:

…insists upon validation and verification, so these valves are proof-tested at regular intervals. A partial stroke test (PST) is performed, decreasing the pressure to move the valve from 1 to 30%.

These tests improve:

…the PFD_AVG of the valve by helping diagnose possible valve failures before they occur, moving the SIS valve into the realm of predictive maintenance.

Read the article for a greater understanding of these concepts and additional ones such as mean time to fail (MTTF) and how it’s used in the determination of suitability for the risk mitigation required by the safety instrumented function.

Visit the Valves, Actuators & Regulators section and Safety Consulting Services section on Emerson.com for more on the final elements and solutions to apply to meet the risk mitigation requirements of your safety applications.

You can also connect and interact with other valve and functional safety experts in the Valves, Actuators & Regulators and Control & Safety Systems groups in the Emerson Exchange 365 community.

The post Understanding Functional Safety Concepts and Final Element Suitability appeared first on the Emerson Automation Experts blog.

Exercising Solenoid Valves in Safety Applications

Jim Cahill — Mon, 06 Jan 2020 20:11:47 GMT

Joe McHugh

Valves used in safety applications tend to stay in opened or closed positions for very long, time intervals. As Emerson’s Joe McHugh explained in a Plant Engineering article, Double up on solenoid safety:

…all valves experience stiction if they remain inactive for too long. (Note: Stiction is the friction that tends to prevent stationary surfaces from being set in motion.)

These valves must be moved periodically, especially a solenoid valve, since:

…if this valve experiences stiction-related failure, the emergency shutdown valve won’t be able to stop the flow of a flammable or even explosive fluid — leading to possible catastrophe.

In a safety instrumented function, solenoid valves are part of the final element which are designed to move the process to a safe state.

In addition to the ESD [emergency shutdown] valve, they can include a pneumatic, electric or hydraulic actuator and solenoid valve.

To address the stiction concerns, the solenoid valve must be regularly tested.

Periodically testing solenoid valves serves two mechanical purposes: It prevents stiction, and it proves it isn’t there to begin with. Bringing the valve through a single cycle is all that’s necessary. De-energize the solenoid coil so the valve fully closes, and then reenergize the coil to return the valve to the open position.

The problem with testing by this process is that it shuts down the process. But, by:

…adding a second solenoid valve to the design of the ESD valve, each solenoid can be tested individually.

Emerson’s ASCO Redundant Control System (RCS):

…is a proven pilot valve arrangement that has no single point of failure and provides built-in redundancy and diagnostics to optimize plant safety and reliability while maximizing uptime…

Joe describes some key advantages of this redundancy which enables automated online testing and online maintenance, avoids nuisance trips, made with 316L stainless steel for corrosive environments, and provides high safety reliability for applications up to SIL 3.

Read the article for more on these advantages as well as safety instrumented system architectural considerations. Visit the Redundant Control Systems page on Emerson’s ASCO website for more and connect & interact with other solenoid valve experts in the Fluid Control & Pneumatics group in the Emerson Exchange 365 community.

The post Exercising Solenoid Valves in Safety Applications appeared first on the Emerson Automation Experts blog.

A Strategic Partnership Driving Valve Operational Performance Improvement

Jim Cahill — Fri, 13 Dec 2019 21:16:59 GMT

Jaime Miller

Manufacturer and producer reliability teams focus much of their efforts around the large plant assets including pumps, compressors, and control systems to maintain efficient and reliable operations. Valves, actuators and regulators often don’t get this same attention. Yet, these final control elements can have a major impact on the performance of the process.

I caught up with Emerson’s Jaime Miller about ways that that this issue can be addressed to drive reliability, reduce variability and maximize uptime.

To support these ongoing operations performance improvements around these valves, actuators, regulators and other final control elements, Jaime described the Main Valve Partner strategic relationship to help address these opportunities.

This strategic relationship offers extensive support and expertise in planning and executing plant projects and maintaining and optimizing plant operations. Emerson’s breadth of valve, actuator, and regulator product offering, OEM engineering expertise, global reach, digital efficiency tools, and scalable, proven solutions enable our customers to work towards Top Quartile performance.

She noted, when we look across the full lifecycle of a plant, we can see various critical stages where there are significant improvement opportunities related to valve assemblies. Valves matter because they have significant impact on both unplanned shutdowns and slowdowns and they’re one of the assets that require the most operational and maintenance spend. As our customers’ strategic partner, we can help them uncover areas that impact their ability to achieve operational excellence and help them find the right solution.

As a strategic partner, our Emerson Lifecycle Services teams can work with customers during installation and commissioning, ongoing operations, shutdowns, turnarounds & outages, and ongoing asset optimization.

During installation and commissioning, compliance management, asset planning & tracking, OEM certified technicians, and application & safety expertise enable a successful handover from plant construction or a shutdown, right into startup. Emerson experts help to minimize the risks and costs often involved with this stage.

During ongoing operations, maintenance strategy programs, installed base analytics, diagnostics & risk-based inspection, and inventory management enable optimization of maintenance spend. Emerson support and expertise help customers reduce valve operating expenses.

During shutdowns, turnarounds and outages (STOs), a digitally-enabled proven process, asset health assessment, parts distribution & QuickShip, and mobile service centers enable accuracy and efficiency in scoping, planning, and executing STOs. Onsite support teams and digital tools help to keep STOs on time and within budget.

Proactively monitoring final control assets enables asset performance optimization. Combining resident asset engineers with the data-gathering and analytics enables actionable decisions to drive reliability, availability and safety improvements. Our support here allows our customers to move toward asset management with predictive diagnostics to enable proactive maintenance planning, minimize unplanned failures, and increase uptime.

This Main Valve Partner strategic relationship with plant operations helps to minimize risk and cost during the installation and commissioning stage, reduce valve operating expenses while running the plant, execute turnarounds on time and within budget, and increase asset uptime through the life of the plant.

Visit the Lifecycle Services – Valves, Actuators & Regulators section on Emerson.com for more on the end-to-end services to drive these performance improvements. You can also connect and interact with other final control element experts in the Valves, Regulators & Actuators group in the Emerson Exchange 365 community.

The post A Strategic Partnership Driving Valve Operational Performance Improvement appeared first on the Emerson Automation Experts blog.

Control and Isolation Valve Qualification Testing

Jim Cahill — Fri, 06 Dec 2019 20:58:52 GMT

Jason Jablonski

Just as people require certain qualifications to perform specific tasks, so does instrumentation, final control elements, control systems and other components in an automation architecture.

In a very informative Chemical Engineering Progress (CEP) article, Purchase a Qualified Valve for Your Operation, Emerson’s Jason Jablonski highlights numerous qualification standards and criteria for control and isolation valves.

Jason opens highlighting the importance of using the right valve for the intended application.

Proper valve operation is necessary to prevent hazardous fluid releases, equipment damage, and unstable plant control, all of which can be dangerous and costly.

The qualification process is dictated by the standard to which it is trying to adhere. Most standards testing specifications:

…require that a third-party witness attend, observe and document the tests.

Equipment for this testing can include:

…bunker and hydrostatic pumps, heat tape and insulation, thermocouples, torque and force meters, fluid leak meters, and mass spectrometers for evaluating fugitive emissions.

Typical documentation:

…includes general assembly drawings, calculations, material certificates, parts lists, references, and other miscellaneous information related to internal equipment and processes.

These test reports given to suppliers and shared with their customers are used by the customers to add the manufacturers’ control and isolation valves:

…to the approved manufacturer’s list (AML) for that product category. Depending on the specification, recertification may be required on a regular basis, such as every five years.

Jason lists numerous valve standards with a description of their coverage. These standards include: API [American Petroleum Institute] RP 591, API 598, API 599, API 600, API 602, API 603, API 608, API 609, API 623, API 624, API 641, ASME (American Society of Mechanical Engineers) B16.5, ASME B16.10, ASME B16.34, ANSI/FCI (American National Standards Institute/Flow Control Institute) 91-1, ISO (International Organization for Standardization) 15848, Shell MESC (Material and Equipment Standards and Code) 77/300, Shell MESC 77/312.

These standards address many areas of valve qualification testing including limited sample sizes, limited material options, limited testing conditions, testing subjectivity, variation and consistency, and changing standards.

Jason highlights some of the production performance testing performed on valves from Emerson. These can include seat leakage detection, valve stroke times, hydrostatic pressure testing, and valve signature (calibration curve) plots.

Read the article for much more on tests around production, seat leakage, stem packing, fugitive emissions, pressures, and cavitation/flashing/noise control, and more. You’ll come away much wiser about the qualification testing performed to assure the control or isolation valve meets the requirements for your application.

Visit the Valves, Actuators & Regulators section on Emerson.com for more on the best valve for your application. You can also connect and interact with other valve experts in Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

The post Control and Isolation Valve Qualification Testing appeared first on the Emerson Automation Experts blog.

Improving Control Valve Reliability through Valve Condition Monitoring

Jim Cahill — Mon, 18 Nov 2019 14:00:00 GMT

Sumitaka Ichiki

An Asian refiner sought to improve reliable operations around their control valves a decade ago. I caught up with Emerson’s Sumitaka Ichiki who shared the story of their journey to more reliable operations.

Using the Fisher FlowScanner valve diagnostic software, they analyzed the dynamic response of many of their critical valves. Based on their findings, they decided to see if they could improve performance of a critical control valve using a Fisher FIELDVUE DVC6000 digital valve controller as a proof of concept in one of their refinery units.

The diagnostics provided by the digital valve controller coupled with the operational analytics in the AMS Valvelink application convinced them to install the DVCs on a broad range of critical control valves.

Later that year during a scheduled turnaround, the refinery staff installed around 70 DVC6000s and a digital network. Over the last several years, this number has grown to around 180 installed DVCs. This wealth of diagnostics had some drawbacks from too many alerts and too few in plant experts to assess the data and form recommendations on actions to take.

To better take advantage of the diagnostic information to improve overall reliability, this refiner contracted the Emerson team to provide valve condition monitoring services. This service enables Emerson valve experts familiar with the ValveLink diagnostics to remotely monitor the performance and provide recommendations on what valves require attention and which should be reworked during the next turnaround.

This connected service works by having the ValveLink application send valve condition and alert information to the cloud, based on Microsoft Azure technology, where further analytical processing can be performed and Emerson experts can review the information and offer actionable recommendations to the operations staff.

This data connection is made through a firewall where the Emerson experts have read-only access to the flow of data coming into the Azure environment. A data diode is being added for further levels of cybersecurity.

With the success in improving critical control valve reliability, this refiner is expanding the focus on reliability and safety to other areas outside of control valves using wireless sensors to monitor equipment, such as on-off valves using Fisher 4320 wireless position monitors.

This refiner has documented savings from loss avoidance to deliver a positive return on investment for the project and ongoing connected services.

Visit the Valve Condition Monitoring Service and Connected Services sections on Emerson.com for more on how to turn this wealth of diagnostic data into actionable information to improve safety, reliability, energy & emissions, and production performance. You can also connect and interact with other connected services experts in the IIoT & Digital Transformation group in the Emerson Exchange 365 community.

The post Improving Control Valve Reliability through Valve Condition Monitoring appeared first on the Emerson Automation Experts blog.

Valve Condition Monitoring Connected Services

Jim Cahill — Mon, 28 Oct 2019 15:16:07 GMT

One path in digital transformation programs is to drive reliability improvements of plant assets by moving from reactive maintenance to condition based maintenance of the equipment.

Saurabh Pathak

I caught up with Emerson’s Saurabh Pathak who shared a case study with me of a large, Middle Eastern natural gas transportation & distribution company. This company had a continuous improvement program to improve asset performance and optimize the process. One big area of focus is this shift from planned maintenance to predictive maintenance using online condition monitoring technology.

The scope of this online condition monitoring effort includes wireless vibration sensors for motors, ultrasound sensors, and digital valve controllers monitoring control valve performance. There are also plans to do condition monitoring on gas chromatographs and ultrasonic flow meter measurements on custody transfer systems.

The asset condition data comes from field staff, process data from the control system, and these online condition monitoring sources. It is fed into a closed-loop asset performance management (APM) process which provides for failure reporting, analysis and corrective action management that is connected with their computerized maintenance management system (CMMS).

One objective of this program was to enhance the reliability and availability of the control valves in the process and extend the time between plant turnarounds. To address this objective, they wanted to shift from reactive alert monitoring to condition monitoring. Their vision was to perform remote monitoring of all critical assets, beginning with the control valves, from a central office.

A key technology to enable this remote monitoring were the Performance Diagnostics (PD) in the Fisher FIELDVUE DVC6200 digital valve controllers. These diagnostics include the In-Service Online and Out-of-Service diagnostics tests. Some of the early valve problems that can be detected In-Service/Online thru the diagnostics include improper stroking speed, excess or reduced friction leading to stiction or process leak, insufficient air supply, poor throttling performance, seat integrity, oscillation due to loop tuning or instrument or accessories degradation, erratic performance, pneumatic leaks, regulator degradation, actuator degradation, worn valve components, online trending and alerts. These diagnostics allow early identification of most hidden valve failure modes supporting a predictive maintenance vs. reactive approach.

In addition, the associated online alerts include travel cutoffs and limits, minimum opening and closing times, input characterization behavior (linear, equal percentage, quick opening, and custom), trending and the following alerts: travel deviation; supply pressure, travel alerts; drive signal; cycle counter. Travel accumulation can be monitored continuously for early identification and notification.

Coupled with the ValveLink software, the online diagnostics are complemented by the Out-of-Service/Offline diagnostic tests (dynamic error band, drive signal, step response, and valve signature), providing comprehensive electronics and mechanical integrity checks, and overall valve asset performance health condition.

Issues with the prior time-based plant maintenance practices were that some valves pulled for service did not require repairs, those that were not planned for repair required it, spare parts management was uncertain, and not addressing these issues could delay start-ups.

Once the objectives and vision were established, the company staff met with members of the Emerson Valve Connected Services team to define a scope and key performance indicators (KPIs) accompanied by a site walkdown and shutdown/turnaround/outage (STO) plan review to establish a plan to execute the valve condition monitoring project. The plan included identification of the critical valves across the site and information shared with Emerson valve experts to data analysis in order to provide actionable recommendations to the staff.

Once the digital valve controllers were installed and the Emerson Connected Services team engaged, Saurabh shared some examples of valves that were identified with abnormal closing profiles, leaks beyond the class shutoff ratings, and ones with excessive friction. Through early notification of these issues, the repairs could be scheduled when possible. Other issues identified included stuck valves, gland leaks, and feedback linkage misalignments.

The company estimated the ROI from this Valve Condition Monitoring program at 40% of overhauling cost and expansions of the program to other sites and valves within this site are on the project roadmap.

Visit the Valve Condition Monitoring and Connected Services sections on Emerson.com for more on the technologies and solutions to improve the asset reliability at your organization. You can also connect and interact with other valve experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

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Approaches to Partial Stroke Testing Safety Valves

Jim Cahill — Wed, 23 Oct 2019 12:30:22 GMT

The safety valve within a safety instrumented function (SIF) must be tested regularly to help assure proper operation in the event of a safety demand. Operators usually perform an offline full stroke test during a scheduled shutdown because of the impact of this test on the process. But when a SIF (a.k.a. safety loop) requires more frequent testing, users can perform a partial stroke test (PST), per the global IEC 61511 safety standard, while the valve is online.

During a PST, the valve is stroked a portion of its total travel to verify it is not stuck and to uncover other dangerous failures. The solenoid valve (SOV) can also be tested by briefly removing power to the solenoid valve and examining the resulting pressure drop across the solenoid valve. These tests help to extend the interval between full-stroke tests.

Digital valve controllers, such as the Fisher FIELDVUE DVC6200 SIS, perform these tests on demand or scheduled through applications such as AMS Device Manager & ValveLink software or control systems such as the DeltaV distributed control system.

Riyaz Ali

I caught up with Emerson’s Riyaz Ali. He noted that the digital valve control with PST capabilities for safety applications has been proven in use for years and years. Digital valve controller technology itself has been available for a quarter of a century. Some newer solutions have begun to emerge where the integration of PST control electronics into a single unit with the termination housing of a solenoid valve.

Riyaz highlighted some differences in these approaches. A digital valve controller-based PST device has a built-in travel sensor, pressure sensor and velocity sensor to provide comprehensive diagnostics around the performance of the valve. The integrated PST electronics with SOV-based technology (Smart SOV) requires at least an external travel sensor and pressure sensor along with its associated electrical wiring and pneumatic tubing to get similar diagnostics.

The external travel sensor requires power supply from the control system to operate and needs to be properly and accurately mounted and aligned. Similarly, the external pressure sensor requires an additional mechanical tapping in the pneumatic output line to actuator. This is built-in for a digital valve controller-based solution. These integral travel and pressure sensors also cut down the response lag, avoiding a delayed action.

The Smart SOV approach requires different models, depending upon the process line connection size. The digital valve controller approach requires only a simple and economic external SOV to stock. The temperature range of operation for a digital valve controller is -40 to 85 degC. This range is much greater than for the Smart SOV approach.

Digital valve controllers continuously monitor the health of internal components helping to assure its availability when needed. This continuous monitoring is available through the ValveLink software with Network Scan for Critical Alerts. For the Smart SOV approach, component tests are done by interruption of power (24VDC – DO) to the SOV.

Fisher FIELDVUE DVC6200 SIS

The digital valve controller is a smart positioner plus an external SOV pneumatically in series. The SOV is considered as a Type A simple device improving its reliability numbers. Smart SOVs are classified as Type B devices as per IEC 61508 part 2 table 3. Type A and Type B are defined in IEC61508 part 2.

Another consideration is common cause failure. Smart positioners for SIS with external SOVs pneumatically in series provides redundancy in case of a safety demand. These allow each component to take valve to safe state, which provides higher levels of safety and reliability. This approach is in line with IEC 61511 part 3, clause 3.4.

Checking the health of an SOV is simplified with a digital valve controller mounted pneumatically in series. SOV health monitoring via a pressure blip can be seen on ValveLink. With a Smart SOV approach, there are no visual results of an SOV’s health.

A digital valve controller with the external SOV pneumatically in series will have higher spurious trip rate. To improve MTTFs (Mean Time to Fail Spurious) presently these smart positioners can use a reverse type relay, which will NOT contribute to MTTFs. In case of any electrical signal failure or input current signal to the smart positioner, these will NOT cause a spurious trip. Hence, two devices pneumatically in series will have MTTFs for a single device (SOV Type A device only). A digital valve controller and external SOV, pneumatically in series, will be an ideal solution from a safety, reliability and plant availability standpoint.

Digital valve controllers have rich diagnostics including valve signature capabilities, which enables a virtual X-ray of valve internals. These diagnostics help to avoid the need to pull the valve out of line for inspection. Valve signatures provide a foot print of the valve body, actuator and accessories mounted, saving time and money during a plant turnaround—to establish a base line, if the valve needs to be taken out of line for maintenance.

Some of the digital valve controller diagnostics include valve signature, dynamic error, drive signal, data analyzed and displayed on actuator spring rate, bench set, potential packing problems, seat load and torque requirements, compare and overlay capabilities allows to check previous valve curve.

From an integration standpoint, a digital valve controller allows easy integration to any control system with broad HART capabilities for easy display on the operators’ HMIs. A Smart SOV has very limited integration capabilities.

Riyaz highlighted a few other capabilities in digital valve controllers not available in Smart SOVs including built-in protection of inadvertently moving valve to more than 30% travel, ramping with different speed to suit process, pause times to eliminate overshoot at end of travel, scheduling partial stroke test for specific date and time, having valve stuck alerts, updating electronics while connected, and checking shaft integrity.

Finally, a digital valve controller has a built-in position transmitter that is completely independent from the positioner function. In case of an electrical signal failure, the position transmitter signal is still available. A Smart SOV requires an external position transmitter, which adds to the hardware and installation & mounting costs.

Visit the Digital Valve Controllers section on Emerson.com for more on the capabilities inherent in these devices. You can also connect and interact with other digital valve controller/smart positioner experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

The post Approaches to Partial Stroke Testing Safety Valves appeared first on the Emerson Automation Experts blog.

Assuring Control Valve Quality

Jim Cahill — Fri, 04 Oct 2019 13:54:52 GMT

Brant Pfantz

Control valves are the workhorses of most processes. They touch the process fluids and often contend with many challenges—abrasive and corrosive fluids, high pressures and temperatures, and vibrations caused by piping and surrounding process equipment, to name a few.

In a Processing magazine article, Valve Sourcing Goes Global, Emerson’s Brant Pfantz highlights the many qualifications and practices suppliers must undertake for the control valves to meet the demanding requirements of their intended applications.

Brant opens by noting that users may have concerns about where the control valves are made. He shares Emerson’s approach in assuring control valve quality.

For Emerson, it:

…enforces a comprehensive quality specification for its Fisher control valves [hyperlink added by me] that must be met by suppliers of pressure-containing and structural metal castings. The quality specification includes more than a dozen requirements that apply to the following areas:

Supplier qualification

Welding procedures

Marking inspection and testing

Tryout and sample castings

Production castings

Certification of compliance

The foundry suppliers must pass a quality review with the Emerson team and:

…must demonstrate a record of qualification by a third-party inspection agency and conform to various standards, such as ISO 9001:2000, ASME, A2LA, PED and others.

From a welding procedures standpoint:

…procedures and welder qualifications must meet ASME Section IX (or EN ISO 15614-1 and ISO 9606-1) qualification standards.

The control valve bodies:

…have markings…that identify the foundry that poured the casting and that indicate the heat code. Material identification is also typically shown on the body casting, such as CC, CF8M, CN7M and others.

The Emerson team conducts visual inspections and mechanical tests, such as hydrostatic pressure testing on these castings, looking for:

…visually detectable weeping or leaking through the pressure boundary walls that are part of the valve assembly…

Materials used in casting are highly dependent on the application. For example, to avoid hydrogen sulfide stress cracks in oil & gas production applications:

Carbon steel castings for valves intended for use in oil and gas applications must meet NACE SP0472 recommendations that chemical composition be controlled to less than 0.43% carbon equivalency.

Read the article for more on the applicable standards, foundry qualifications, and quality practices to assure that you have right control valve to meet your application’s requirements. You can also connect and interact with other valve experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

The post Assuring Control Valve Quality appeared first on the Emerson Automation Experts blog.

Case Study on Valve Monitoring Connected Services

Jim Cahill — Thu, 26 Sep 2019 15:37:00 GMT

An Emerson local business partner's Evelyn Rosales presented with a petrochemical producer, Maximize your Turnaround Efficiency using Connected Services at the 2019 Emerson Exchange conference.

This petrochemical producer began valve condition monitoring a year ago on over 100 valves. Diagnostic data is automatically connected weekend with a monthly valve health summary report delivered to the plant. The objective to move away from a reactive and scheduled maintenance approach to a proactive, condition-based approach. This will help avoid unnecessary disassembly of the valves during the turnaround project.

The diagnostics also help prioritize the work that needed to be performed on the valves during the turnaround. Parts could be pre-ordered and be onsite and ready to use.

The valve condition monitoring report divides the valves into 3 different priorities with priority 1 being major impact valves in the process. A priority 4 was added to address valves with a “data impact” which are valves that require a review of the existing configuration.

A challenge of the facility is that it could be shutdown frequently based on the cost of the raw materials feeding the plant. When the costs were high, it was not economic to produce the petrochemicals and the plant was shut down. The presenter joked that as a result they were extremely good at startups.

It took 18 months to get the condition-based valve monitoring service sold to the management staff. Diagnostics found a valve with a broken stem that has caused a plantwide shutdown which finally sold the need for this valve monitoring connected service. The next turnaround is coming soon and the priorities of the work to be done with the valves is now set and the parts required secured.

Some examples of what needs to be done include a valve with an abnormal throttling range that will require resizing. Another example is a positioner that has a problem with the I/P converter which is affecting the actual position of the valve from what the control system wants it to be. The third example is a valve not closing properly and providing a tight shutoff that is required for the process.

Knowing these conditions in advance greatly improves the productivity of the maintenance staff to focus their efforts during the turnaround and not be on the critical path of the turnaround schedule.

Going into the turnaround, over 40% of the valves do not need to be touched and less that 60% of the 100+ valves will need some form of maintenance from very minor to major overhaul. The time required to perform these activities can be estimated much more accurately than was possible in prior turnarounds. Spare part purchases were reduced by a factor of 4. Another key benefit was reinforcing the condition-based approach practice for valve maintenance.

Looking forward, there will be more focus on valve optimization and valve performance to improve the reliability, production and energy management in their petrochemical production process.

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Innovative Slurry Isolation Valve Remote Control

Jim Cahill — Tue, 24 Sep 2019 21:34:26 GMT

Emerson’s Peter Woodhead presented Remote Control Panels: Innovative & Effective Solution for Isolation Valves at the 2019 Emerson Exchange conference. Peter is from Brisbane, Australia where they design and manufacturer Lunkenheimer slurry valves.

The mining customer challenged the Emerson team to remotely control some slurry isolation valves. The isolation valves were applied on a backpressure vessel with the digestion stage in an alumina factory. The backpressure vessel is located on a steel platform with 3 of 5 isolation valves positioned 3 meters above the platform. They wanted to remotely control the valves to improve personnel safety and eliminate fixed access walkways.

This type of remote control had never been done before. Factory testing could not simulate the temperature conditions found in the actual process. The approach to solve this challenge was to control the hydraulic system using PLCs, digital I/O, relays and pressure & position sensors. Push-button operation was adopted for most operations to improve simplicity and reliability.

Peter described how typical manual operations work on these valves. A pinion shaft is rotated to open & close the valve. A staple in is for open & close and out to grind the seat. In this process, scaling is a problem and the lines and isolation valves must be flushed periodically with a caustic chemical with and valve grinding operation to remove the scale.

For remote control, an innovative disc brake replaced the staple. For this application the disc brake required 6 kN.m brake torque. It’s activated remotely via hydraulic pressure. There is no need for a hammer which reduces risks for operators.

The second innovation was a clutch to replace the jam nut in the manually-operated approach. The third innovation was the remote-control panel. It included push-button control, manual/maintenance/emergency manual modes, selectable switch for seat back-off to suit available grinding torque, open/close sensors displayed on control panel, and PLC control.

The panel had 5 modes—open, close, grind, manual & maintenance. Visual LED indicators indicate feedback such as achieved mode change result, warning, mode, and seat backoff range.

This project developed first-of-their-kind mechanisms, and control system to remotely operate a globe valve with innovations—disc brake, hydraulic clutch, and remote-control panel.

The post Innovative Slurry Isolation Valve Remote Control appeared first on the Emerson Automation Experts blog.

Wirelessly Monitoring Tank Thief Hatches to Avoid Regulatory Fines

Jim Cahill — Thu, 05 Sep 2019 20:44:34 GMT

I shared a great case study from the oil patch yesterday with time savings with wireless pressure monitoring at the well head. Today, let’s continue with another great case study from the oil patch with a Control magazine article, Use wireless to monitor thief hatches.

The article’s author opens describing what a thief hatch is. These devices are:

…installed on the top of low-pressure and atmospheric tanks in the oil & gas, chemical, pharmaceutical, biogas, water treatment and other industries to allow access to the tank. They can be used to take samples of the tank’s contents and determine the level of the tank, and they protect the tank from overpressure and excessive vacuum.

When an overpressure or excessive vacuum event occurs:

…the hinged hatch cover will break its seal, lift and allow the pressure to escape to the atmosphere. When the pressure or vacuum is reduced to the setpoint, the seal is reseated by either spring, sealing the tank.

The challenge which may lead to regulatory fines?

When a thief hatch closes—either from gravity or from a worker closing it—the hatch may not seal unless it is firmly latched. This allows vapors in the tank to leak into the atmosphere, which can violate regulations.

For the oil & gas producer operating in the U.S. State of Colorado, the regulations require:

…monitoring of thief hatches on oil and water tanks to prevent release of methane and volatile organic compounds (VOCs) to the atmosphere.

State inspectors:

…document any open thief hatches, and compare their records to the producer’s by time and location. If the producer can confirm the thief hatch was open—perhaps for maintenance or sampling—at the same time as the inspector found it open, then there’s no problem and no penalty. If the producer cannot confirm from its records as to why the hatch was open, penalties and fines are assessed.

Here was the solution this oil & gas producer used to monitor their thief hatches [hyperlink added by me]:

Rosemount 702 discrete WirelessHART transmitters…can be installed on existing thief hatches and tank batteries to effectively ensure the hatches are closed and latched. The concept is fairly simple: A switch at the latch…detects when the latch is closed.

Read the article for more on the inner workings of the thief hatch and switch monitoring for proper closing as well as the wireless architecture applied, and the business results achieved by fine avoidance. It’s yet another example of using Industrial Internet of Things sensing technologies to improve business performance.

Visit the Industrial Wireless Technology and Tank Vents and Hatches sections on Emerson.com for more on the application of these technologies. You can also connect and interact with wireless sensor and tank vent/hatches experts in the IIoT & Digital Transformation and Valves, Actuators & Regulators groups in the Emerson Exchange 365 community and/or at the September 23-27 Emerson Exchange conference in Nashville.

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