If a valve doesn’t operate, your course of 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 leads to a harmful failure. Solenoid valves in oil and fuel applications control the actuators that move massive course of valves, including in emergency shutdown (ESD) methods. The solenoid must exhaust air to enable the ESD valve to return to fail-safe mode every time sensors detect a dangerous course of situation. These valves must be quick-acting, durable and, above all, reliable to stop downtime and the associated losses that occur when a process isn’t working.
And this is much more important for oil and gas operations where there could be restricted energy obtainable, such as distant wellheads or satellite tv for pc offshore platforms. Here, solenoids face a double reliability problem. First, a failure to function correctly cannot solely cause costly downtime, however a maintenance call to a remote location additionally takes longer and prices more than an area repair. Second, to diaphragm seal for energy, many valve producers resort to compromises that truly cut back reliability. This is bad sufficient for course of valves, however for emergency shutoff valves and other security instrumented methods (SIS), it’s unacceptable.
Poppet valves are usually better suited than spool valves for remote places as a outcome of they are less complex. For low-power applications, 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 reliable 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 present and material characteristics are all forces solenoid valve producers have to overcome to build the most dependable valve.
High spring drive is key to offsetting these forces and the friction they cause. However, in low-power applications, most manufacturers need to compromise spring force to permit the valve to shift with minimal power. The reduction in spring drive results in a force-to-friction ratio (FFR) as low as 6, though the commonly accepted safety stage 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 pressure while nonetheless maintaining a high FFR.
For example, the valve operates by electromagnetism — a current stimulates the valve to open, permitting the media to circulate to the actuator and transfer the method valve. This media could additionally be air, however it might even be natural gasoline, instrument gas and even liquid. This is very true in distant operations that should use no matter media is available. This means there is a trade-off between magnetism and corrosion. Valves by which the media is out there in contact with the coil must be made of anticorrosive materials, which have poor magnetic properties. A valve design that isolates the media from the coil — a dry armature — allows using highly magnetized material. As a end result, there isn’t any residual magnetism after the coil is de-energized, which in turn allows faster response occasions. This design additionally protects reliability by preventing contaminants in the media from reaching the inside workings of the valve.
Another factor is the valve housing design. Usually a heavy (high-force) spring requires a high-power coil to overcome the spring strength. Integrating the valve and coil right into a single housing improves effectivity by stopping vitality loss, allowing for the usage of a low-power coil, resulting in less energy consumption without diminishing FFR. This integrated coil and housing design also reduces heat, stopping spurious trips or coil burnouts. A dense, thermally efficient (low-heat generating) coil in a housing that acts as a warmth sink, designed with no air hole to trap heat across the coil, nearly eliminates coil burnout concerns and protects course of availability and safety.
Poppet valves are generally better suited than spool valves for distant operations. The decreased complexity of poppet valves increases reliability by reducing sticking or friction points, and reduces the number of parts that may fail. Spool valves typically have large dynamic seals and tons of require lubricating grease. Over time, particularly if the valves usually are not cycled, the seals stick and the grease hardens, resulting in greater friction that must be overcome. There have been reviews of valve failure as a result of moisture in the instrument media, which thickens the grease.
A direct-acting valve is your finest option wherever attainable in low-power environments. Not solely is the design much less complicated than an indirect-acting piloted valve, but in addition pilot mechanisms typically have vent ports that can admit moisture and contamination, resulting in corrosion and allowing the valve to stick within the open place even when de-energized. Also, direct-acting solenoids are particularly designed to shift the valves with zero minimal pressure requirements.
Note that some bigger actuators require excessive move charges and so a pilot operation is critical. In this case, you will want to verify that all components are rated to the same reliability rating as the solenoid.
Finally, since most remote places are by definition harsh environments, a solenoid put in there should have robust development and be succesful of face up to and operate at excessive temperatures while nonetheless sustaining the same reliability and security capabilities required in much less harsh environments.
When selecting a solenoid management valve for a remote operation, it is attainable to discover a valve that does not compromise performance and reliability to cut back power calls for. Look for a high FFR, easy dry armature design, nice magnetic and warmth conductivity properties and strong development.
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 utility engineering and business development to the oil, gasoline, petrochemical and energy 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 expertise in new enterprise development and customer relationship administration to the oil, gas, petrochemical and power industries and is certified as a pneumatic specialist by the International Fluid Power Society (IFPS).
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