Solenoid valve reliability in lower energy operations

If a valve doesn’t function, your process doesn’t run, and that’s cash down the drain. Or worse, a spurious trip shuts the method down. Or worst of all, a valve malfunction leads to a dangerous failure. Solenoid valves in oil and gas applications control the actuators that move massive course of valves, together with in emergency shutdown (ESD) systems. The solenoid needs to exhaust air to allow the ESD valve to return to fail-safe mode each time sensors detect a harmful course of scenario. These valves have to be quick-acting, sturdy and, above all, reliable to stop downtime and the related losses that happen when a process isn’t working.
And that is much more essential for oil and fuel operations the place there could be limited energy out there, corresponding to distant wellheads or satellite offshore platforms. Here, solenoids face a double reliability problem. First, a failure to function appropriately can not solely trigger expensive downtime, however a maintenance name to a distant location also takes longer and prices more than an area restore. Second, to reduce the demand for energy, many valve producers resort to compromises that actually scale back reliability. This is bad enough for process valves, however for emergency shutoff valves and other security instrumented systems (SIS), it is unacceptable.
Poppet valves are generally higher suited than spool valves for remote locations because they’re much less complicated. For low-power functions, search for a solenoid valve with an FFR of 10 and a design that isolates the media from the coil. (Courtesy of Norgren Inc.)
Choosing a dependable low-power solenoid
Many factors can hinder the reliability and efficiency of a solenoid valve. Friction, media flow, sticking of the spool, magnetic forces, remanence of electrical present and material traits are all forces solenoid valve producers have to beat to construct the most reliable valve.
High spring pressure is essential to offsetting these forces and the friction they trigger. However, in pressure gauge 4 นิ้ว -power functions, most producers should compromise spring drive to permit the valve to shift with minimal power. The discount in spring drive results in a force-to-friction ratio (FFR) as low as 6, although the commonly accepted safety degree is an FFR of 10.
Several parts of valve design play into the amount of friction generated. Optimizing each of those allows a valve to have greater spring force while nonetheless maintaining a excessive FFR.
For instance, the valve operates by electromagnetism — a current stimulates the valve to open, permitting the media to flow to the actuator and transfer the method valve. This media could additionally be air, but it may even be pure fuel, instrument fuel and even liquid. This is particularly true in remote operations that should use whatever media is on the market. This means there is a trade-off between magnetism and corrosion. Valves by which the media comes in contact with the coil should be made of anticorrosive materials, which have poor magnetic properties. A valve design that isolates the media from the coil — a dry armature — allows the utilization of highly magnetized materials. As a result, there isn’t any residual magnetism after the coil is de-energized, which in turn allows faster response occasions. This design also protects reliability by preventing contaminants within the media from reaching the inner workings of the valve.
Another factor is the valve housing design. Usually a heavy (high-force) spring requires a high-power coil to beat the spring power. Integrating the valve and coil right into a single housing improves effectivity by preventing power loss, allowing for the usage of a low-power coil, resulting in much less energy consumption with out diminishing FFR. This integrated coil and housing design also reduces warmth, preventing spurious journeys or coil burnouts. A dense, thermally efficient (low-heat generating) coil in a housing that acts as a heat sink, designed with no air gap to entice heat around the coil, just about eliminates coil burnout concerns and protects process availability and safety.
Poppet valves are usually higher suited than spool valves for distant operations. The reduced complexity of poppet valves increases reliability by reducing sticking or friction points, and decreases the variety of elements that may fail. Spool valves often have large dynamic seals and lots of require lubricating grease. Over time, especially if the valves aren’t cycled, the seals stick and the grease hardens, leading to greater friction that have to be overcome. There have been reviews of valve failure due to moisture within the instrument media, which thickens the grease.
A direct-acting valve is the finest choice wherever possible in low-power environments. Not solely is the design much less complex than an indirect-acting piloted valve, but in addition pilot mechanisms usually have vent ports that may admit moisture and contamination, resulting in corrosion and allowing the valve to stay in the open position even when de-energized. Also, direct-acting solenoids are particularly designed to shift the valves with zero minimal pressure requirements.
Note that some larger actuators require high flow rates and so a pilot operation is necessary. In this case, it is essential to ascertain that all elements are rated to the identical reliability score because the solenoid.
Finally, since most remote areas are by definition harsh environments, a solenoid installed there will have to have robust building and have the flexibility to withstand and function at excessive temperatures whereas nonetheless maintaining the identical reliability and safety capabilities required in less harsh environments.
When deciding on a solenoid control valve for a remote operation, it’s possible to find a valve that does not compromise efficiency and reliability to reduce power calls for. Look for a high FFR, easy dry armature design, great magnetic and heat conductivity properties and strong building.
Andrew Barko is the sales engineer for the Energy Sector of IMI Precision Engineering, makers of IMI Norgren, IMI Maxseal and IMI Herion model components for vitality operations. He offers cross-functional expertise in software engineering and business improvement to the oil, gasoline, petrochemical and power industries and is licensed as a pneumatic Specialist by the International Fluid Power Society (IFPS).
Collin Skufca is the vital thing account manager for the Energy Sector for IMI Precision Engineering. He provides experience in new enterprise improvement and customer relationship management to the oil, gasoline, petrochemical and power industries and is certified as a pneumatic specialist by the International Fluid Power Society (IFPS).
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