If a valve doesn’t operate, your process doesn’t run, and that is money down the drain. Or worse, a spurious trip shuts the method down. Or worst of all, a valve malfunction results in a harmful failure. Solenoid valves in oil and fuel applications control the actuators that move giant process valves, including in emergency shutdown (ESD) systems. The solenoid must exhaust air to allow the ESD valve to return to fail-safe mode every time sensors detect a harmful course of scenario. These valves must be quick-acting, durable and, above all, dependable to stop downtime and the related losses that happen when a course of isn’t operating.
And this is much more important for oil and fuel operations the place there is limited power available, such as distant wellheads or satellite tv for pc offshore platforms. Here, solenoids face a double reliability problem. First, a failure to operate accurately can’t solely trigger pricey downtime, however a maintenance name to a remote location also takes longer and prices greater than a neighborhood restore. Second, to reduce the demand for power, many valve manufacturers resort to compromises that really scale back reliability. This is dangerous sufficient for course of valves, but for emergency shutoff valves and different security instrumented systems (SIS), it is unacceptable.
Poppet valves are typically better suited than spool valves for distant locations as a end result of they are much less advanced. For low-power functions, look 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 components can hinder the reliability and efficiency of a solenoid valve. Friction, media circulate, sticking of the spool, magnetic forces, remanence of electrical current and material characteristics are all forces solenoid valve manufacturers have to overcome to construct essentially the most reliable valve.
High spring force is essential to offsetting these forces and the friction they cause. However, in low-power applications, most producers need to compromise spring pressure to permit the valve to shift with minimal power. The reduction in spring drive ends in a force-to-friction ratio (FFR) as low as 6, though the commonly accepted safety degree is an FFR of 10.
Several components of valve design play into the quantity of friction generated. Optimizing each of those permits a valve to have higher spring force whereas still sustaining a high FFR.
For example, the valve operates by electromagnetism — a present stimulates the valve to open, permitting the media to move to the actuator and move the process valve. This media may be air, but it may also be pure fuel, instrument gasoline or even liquid. This is particularly true in distant operations that should use no matter media is available. This means there is a trade-off between magnetism and corrosion. Valves in which the media comes in contact with the coil must be made of anticorrosive supplies, which have poor magnetic properties. A valve design that isolates the media from the coil — a dry armature — permits the use of highly magnetized materials. As a outcome, there is no residual magnetism after the coil is de-energized, which in turn allows faster response instances. This design additionally protects reliability by preventing contaminants within the media from reaching the inner workings of the valve.
Another issue is the valve housing design. Usually a heavy (high-force) spring requires a high-power coil to beat the spring energy. Integrating the valve and coil into a single housing improves efficiency by preventing vitality loss, allowing for the use of a low-power coil, leading to much less power consumption without diminishing FFR. This integrated coil and housing design also reduces warmth, preventing spurious trips 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 warmth around the coil, nearly eliminates coil burnout issues and protects course of availability and safety.
Poppet valves are generally higher suited than spool valves for distant operations. เกจวัดแรงดัน250bar lowered complexity of poppet valves increases reliability by reducing sticking or friction points, and reduces the variety of parts that can fail. Spool valves usually have massive dynamic seals and heaps of require lubricating grease. Over time, particularly if the valves are not cycled, the seals stick and the grease hardens, leading to higher friction that have to be overcome. There have been reviews of valve failure due to moisture in the instrument media, which thickens the grease.
A direct-acting valve is the best choice wherever potential in low-power environments. Not only is the design much less complicated than an indirect-acting piloted valve, but in addition pilot mechanisms usually have vent ports that may admit moisture and contamination, leading to corrosion and permitting the valve to stick in the open place even when de-energized. Also, direct-acting solenoids are specifically designed to shift the valves with zero minimal strain necessities.
Note that some bigger actuators require high circulate charges and so a pilot operation is important. In this case, it is necessary to ascertain that every one elements are rated to the same reliability ranking as the solenoid.
Finally, since most remote locations are by definition harsh environments, a solenoid put in there should have strong construction and be ready to withstand and function at extreme temperatures while still maintaining the identical reliability and safety capabilities required in less harsh environments.
When choosing a solenoid control valve for a remote operation, it is potential to discover a valve that does not compromise performance and reliability to reduce energy demands. Look for a high FFR, simple dry armature design, great magnetic and warmth conductivity properties and sturdy building.
Andrew Barko is the gross sales engineer for the Energy Sector of IMI Precision Engineering, makers of IMI Norgren, IMI Maxseal and IMI Herion model elements for power operations. He provides cross-functional experience in application engineering and business growth to the oil, gas, petrochemical and power industries and is certified as a pneumatic Specialist by the International Fluid Power Society (IFPS).
Collin Skufca is the important thing account manager for the Energy Sector for IMI Precision Engineering. He provides expertise in new business improvement and buyer relationship management to the oil, fuel, petrochemical and power industries and is certified as a pneumatic specialist by the International Fluid Power Society (IFPS).
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