B. Gundaboina and A. KMITTA, Emerson, Houston, Texas
Driven by stringent greenhouse gas (GHG) emissions
regulations and technical improvements, electric valve actuators are becoming
increasingly common in applications throughout the process industry. Significantly
reduced power requirements, spring-return and fail-safe features, and a host of
embedded diagnostics have driven the installation of these actuators in an ever-expanding
range of processes.
Unfortunately, diagnostic and equipment
monitoring software has historically been unavailable for this market segment. Despite
adding many actuator diagnostic features, data
monitoring and analytic products have been largely unavailable for electric and
electro-hydraulic actuators until now.
This article focuses on recent software developments
that empower users to monitor these devices, enabling them to detect and
proactively respond to developing issues before failures occur, and to integrate
valves equipped with these actuators into traditional maintenance asset monitoring
Electric actuating options. Until recently, electric actuators saw limited
use in process industries. Typically, actuators were only utilized in remote
areas, had limited torque and were prone to failure. They also had rudimentary
diagnostics that provided little information beyond indicating if the valve was
working. Remote monitoring and connectivity options were largely non-existent.
A global focus on reducing methane and GHG
emissions spurred many users to transition from natural gas–actuated pneumatics
to electrical and electro-hydraulic actuators (FIG. 1). Actuator designs and technology have improved
significantly, allowing some actuator models to achieve zero-emissions
performance, and now include integrated spring-return, fail-safe technology. These
new designs are suitable for safety integrity level shutdown applications and
operate with a fraction of the power required by previous models, while generating
far more torque.
These technical improvements have also made
electric and electro-hydraulic actuators increasingly attractive for applications
where pressurized air is expensive or unavailable. As a result, these actuators
are becoming common in many new capital projects, and they can be retrofitted
to existing valves when needed.
Electric actuators incorporate significant
processing power and advanced diagnostics to operate efficiently and reliably. These
features can be helpful to a technician addressing a problem at the valve.
However, unlike most pneumatic actuators and positioners, few data access
options have existed to connect electric and electro-hydraulic actuators to
existing asset monitoring software networks.
Electric actuator connectivity solutions. Fortunately, the information gap is being
closed with the introduction of software applications specifically focused on
the electric and electro-hydraulic actuating market. These software applications
offer various useful features, including the ability to access device
with current status and alarms—and execute basic
functionality and test commands (FIG. 2).
More advanced applications provide extensive
features, including the ability to perform local partial stroke tests, upload
and download valve configurations (remotely or locally), and capture and store
stroke curves for analysis, troubleshooting and side-by-side comparison (FIG. 3).
While all these features are invaluable to
technicians, the transformational improvements come via advanced data analysis,
analytics and predictive maintenance. Only recently have these data
applications started to utilize the information in the valve’s historical
performance, stroke curves and alarm logs to identify current and developing
problems, and to offer specific suggestions for troubleshooting and repair (FIG. 4).
Data analytics can identify potential issues as
they develop, allowing maintenance personnel to plan outages and avoid
unexpected downtime, which typically translates into significant operating
potential options. Each software application has different
capabilities, so users are advised to evaluate available options and determine
the best alternative for their specific application. Here are some key features
case studies. A chemical plant's maintenance
personnel installed electric actuator monitoring softwarea in their
existing asset maintenance system. They began capturing and comparing torque
curves using the existing Foundation Fieldbus network. Over time, they noticed
some valves were developing a spike in the closing torque, ultimately
attributed to product buildup within the valve. By monitoring the valves for
this spike, they could readily identify problem valves and then pull them for
cleaning before the valve was damaged or production was affected.
application, the remote valve monitoring software detected consistent under-voltage
alarms on a valve. The valve was working, but the analytics suggested a developing
power supply problem. A field check confirmed the power supply was not
operating properly, and it was repaired before an outright valve failure
company used a local Bluetooth connection to perform partial stroke tests on
their valve monitoring software. This allowed the plant to extend its safety
instrumented system interlock testing frequency. The plant also utilized the
captured partial stroke test torque curves to identify valves beginning to coat
Electronic valve actuators have come a long way from the simple,
motorized valves that once dominated the landscape. Fail-safe features, low power
requirements and electro-hydraulic hybrid designs have rapidly broadened the
range of applications, and these devices are becoming increasingly common
throughout the process industries.
While initially slower to market, capable data
monitoring and configuration software is now available for these devices. With several
connectivity options, these new applications offer features that enable technicians
to configure, operate and troubleshoot valves and the associated actuators. These
capabilities are useful and important, but the gathering and utilization of
performance and historical data yields the greatest savings. Advanced data
analytics and actionable repair suggestions enable maintenance departments to
identify and address issues before production is impacted, improving uptime,
reliability and profitability. HP
a Emerson’s DCMlink
is a Senior Product Marketing Manager for Emerson. She earned her BS degree in
mechanical engineering from Osmania University and has spent 12 yr working in
the oil, gas and petrochemical industries, supporting product design and
is a Software Engineering Manager for Emerson. He has spent 16 yr working in
the steel, process automation and software development industries, supporting
operations, controls and manufacturing engineering. Kmitta earned his BS and MS
degrees in electrical engineering from Purdue University.