56
December
2014
HYDROCARBON
ENGINEERING
stroke test device. This section effectively supersedes most of
the display menus of the positioner or partial valve stroke
device and, importantly, allows interactive adjustment of the
tuning parameters.
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A means of downloading and inspecting instrument fault,
condition monitoring event and partial valve stroke test logs
from the system.
Now that data could be collected from the positioner a
method of storing had to be determined. Due to limited storage
memory and screen sizes, tablets and smartphones are not ideal for
file storage and for the display of large amounts of data; however,
they are all equipped withWi-Fi communications. Paladon Systems
created a dedicated website to allow for the uploading of
parameters, log and stroke signature data. The website also allowed
the following additional functions to be added:
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Store, display and edit the positioner or partial valve stroke
device and download back to the tablet and then back on to
the positioner. Note that, if Wi-Fi is locally available, then the
tablet or smartphone can be used for both the communication
with the positioner and with the internet.
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Store and display instrument fault and condition monitoring
logs.
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Store and display stroke signals in both digital and graphical
forms.
Case study
Scope
Amajor American oil company in the Permian Basin wanted to
actuate their existing manual valves to obtain the following benefits:
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Enhanced process control via remote and quicker valve
operation.
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Improved process availability as the site location is prone to
flooding and becomes unreachable during periods of high
rainfall.
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Improved process reliability through the implementation of
condition monitoring and a preventive maintenance program.
The main barrier to achieving the above process improvements
was the lack of an electrical power supply to the site and the
prohibitive costs that would be incurred by installing one.
Parameters
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Midstream oil pipeline.
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Four existing manually operated 4 in. thru conduit
expanding gate and segment Class 600 pipeline gate valves.
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No existing power.
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Class 1, Division 1, Group C&D hazardous locations.
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Low power wireless communication requirement using
existing small solar panel.
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The end user required the following communication
capabilities:
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Command to open.
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Command to close.
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Return signal open/close.
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Partial stroke test.
Solution
The end user already had low wireless power communications
for each location, but no means of actuating the expanding gate
valves remotely. Paladon Americas designed and built four self
contained electro hydraulic systems comprising of the
following:
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Double acting linear hydraulic actuators for direct
mounting to the existing thru conduit gate valves.
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Integral solar panels and rechargeable batteries to power
each system.
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Smart partial valve stroke test device for condition
monitoring.
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Micro programmable logic controller (PLC) with dedicated
LCD display to control valve operation, monitor the
systems’ overall status, provide and display alarm functions.
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Local valve open and close push button station.
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Local/remote selector switch.
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Radio receiver to provide remote wireless control using
existing site communications infrastructure.
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Hydraulic handpump for local valve control in the event of
electrical power loss.
Operation
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Remote electric on/off valve control.
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Local electric on/off valve control.
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Ability to disable remote electric on/off valve control.
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Local manual on/off valve control.
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Automatic partial valve stroke testing every 30 days.
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Due to limited customer inputs, a general alarm would be
created and transmitted wirelessly in the event of any of
the following conditions:
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Valve failure to open on command.
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Valve failure to close on command.
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Low battery charge level.
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Low hydraulic fluid level.
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Failure during valve partial stroke test to move the valve
at all or fail to move the valve to the set partial valve
stroke position (25% of total valve stroke).
Result
Since installation of the systems, the end user has realised all of
the expected benefits as detailed in the project’s scope.
Conclusion
Solar powered electro hydraulic valve automation systems
provide end users with an ideal solution when process control
and reliability are critical design requirements.
Figure 2.
Spring return hydraulic scotch yoke
actuator mounted to a 24 in. Class 600 ball valve.
