For air-operated control valves, the pneumatic power at a constant supply pressure is proportional to the mass flow rate of instrument air. The pneumatic/eletro-pneumatic/microprocessor-based digital valve controller is used on most control valves operated in closed-loop control, where the input signal is continuously changing.
In a Hydrocarbon Engineering article, Improving safety shutdown valve reliability, Emerson’s Stanley Amirthasamy and Lura Parrent share ways to improve the reliability of final elements when they are safety valves. They open noting how safety valves are used to bring a process to a safe state.
In a post, Valve Travel Control-Pressure Fallback, Emerson’s Riyaz Ali shared the process of how a control valve with a digital valve controller could fall back to standard pressure control upon an issue with the travel sensing mechanism.
A Digital Valve Controller, the DVC6200 (HART or Foundation Fieldbus) can detect position feedback problems and automatically revert to I/P [current to pressure] transducer mode to keep the valve operational. This avoids costly unplanned spurious trips, which are critical for plant operational performance.
Many of these IIoT applications, whether powered by the Internet or internal intranets, have become more relevant as employees increasingly work from remote locations, requiring enhanced collaboration among widely dispersed personnel. An example is the remote monitoring of valves, along with collaborating for maintenance and repair, to improve reliability.
New technologies that are truly different often depend on a “killer app” to convince users to take the leap. For the Internet early on, it was email. Suddenly being able to communicate near instantaneously in writing provided visible value people could latch on to, and the rest is history. For industrial users, digital transformation has been similar. How and why it has been adopted in many locations is the topic of Emerson’s Marcelo Carugo’s article in the October issue of Control.
In a LinkedIn essay, Transform to Valve 4.0: Digital Control + Analytics, Emerson’s Jonas Berge describes how the performance of control valves can be more effectively managed and maintained for better operational performance.
In a Pumps&Systems article, Digitalization to Predict Reliability of Mechanical Valves, Emerson’s Riyaz Ali shares ways continuous monitoring technology can help.
Because they directly touch the process flow, control valves play a significant role in the stability, robustness and variability in the process. One bad-acting control valve can create large problems for safe and reliable operations. At last week's AIChE Spring...
A safety instrumented function (SIF) within a safety instrumented system (SIS) consists of a sensor, logic solver, and final element. As part of the IEC 61511 global safety standard, these elements within the SIF must be tested during the operational phase of the...
Partial stroke test is one of the viable means to check mechanical integrity of Final Element of Safety Instrumented Function (SIF) loop. Generally, end users struggle on question of credit of PST for improvement in SIL (Safety Integrity Level). IEC 61508 and IEC...
Happy New Year everyone! I hope your holidays helped to recharge your batteries and get you off to a great start for 2018. I saw this exchange in my email over the holidays about the effects of using low-bleed relays with Fisher DVC6200 digital valve controllers for...
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