Solenoid valve reliability in lower power operations

If a valve doesn’t operate, your process doesn’t run, and that is 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 large process valves, including in emergency shutdown (ESD) techniques. The solenoid needs to exhaust air to enable the ESD valve to return to fail-safe mode each time sensors detect a dangerous process state of affairs. These valves must be quick-acting, durable and, above all, reliable to prevent downtime and the associated losses that happen when a course of isn’t running.
And this is much more important for oil and fuel operations where there’s restricted energy available, such as distant wellheads or satellite offshore platforms. Here, solenoids face a double reliability challenge. First, a failure to function accurately cannot only trigger pricey downtime, but a maintenance name to a distant location additionally takes longer and costs greater than a neighborhood repair. Second, to reduce back the demand for power, many valve manufacturers resort to compromises that truly scale back reliability. This is bad sufficient for course of valves, but for emergency shutoff valves and other security instrumented systems (SIS), it is unacceptable.
Poppet valves are generally better suited than spool valves for remote areas as a end result of they are less advanced. For low-power applications, 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 reliable low-power solenoid
Many factors can hinder the reliability and performance 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 beat to construct probably the most reliable valve.
High spring drive is essential to offsetting these forces and the friction they trigger. However, in low-power purposes, most manufacturers have to compromise spring drive to allow the valve to shift with minimal power. The discount in spring force results in a force-to-friction ratio (FFR) as little as 6, although the widely accepted security level is an FFR of 10.
Several components of valve design play into the amount of friction generated. Optimizing every of these allows a valve to have higher spring drive whereas nonetheless sustaining a high FFR.
For instance, the valve operates by electromagnetism — a current stimulates the valve to open, allowing the media to move to the actuator and transfer the method valve. This media could additionally be air, however it could even be natural gas, instrument fuel or even liquid. This is especially true in remote operations that should use no matter media is available. This means there’s a trade-off between magnetism and corrosion. เกจวัดแรงดันไนโตรเจนราคา by which the media comes in contact with the coil have to be made from anticorrosive supplies, which have poor magnetic properties. A valve design that isolates the media from the coil — a dry armature — allows using extremely magnetized material. As a end result, there is no residual magnetism after the coil is de-energized, which in flip allows faster response times. This design additionally protects reliability by preventing contaminants in 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 strength. Integrating the valve and coil right into a single housing improves efficiency by preventing power loss, permitting for the use of a low-power coil, resulting in much less power consumption without diminishing FFR. This built-in coil and housing design also reduces warmth, preventing spurious journeys or coil burnouts. A dense, thermally environment friendly (low-heat generating) coil in a housing that acts as a warmth sink, designed with no air gap to entice warmth around the coil, nearly eliminates coil burnout issues and protects course of availability and security.
Poppet valves are usually better suited than spool valves for remote operations. The lowered complexity of poppet valves increases reliability by lowering sticking or friction points, and reduces the variety of elements that can fail. Spool valves typically have large dynamic seals and plenty of require lubricating grease. Over time, especially if the valves are not cycled, the seals stick and the grease hardens, resulting in greater friction that should be overcome. There have been stories of valve failure as a result of moisture within the instrument media, which thickens the grease.
A direct-acting valve is the only option wherever possible in low-power environments. Not solely is the design less complicated than an indirect-acting piloted valve, but in addition pilot mechanisms often have vent ports that may admit moisture and contamination, leading to corrosion and allowing the valve to stay within the open position even when de-energized. Also, direct-acting solenoids are particularly designed to shift the valves with zero minimal stress necessities.
Note that some bigger actuators require excessive circulate rates and so a pilot operation is necessary. In this case, you will need to ascertain that all components are rated to the identical reliability ranking as the solenoid.
Finally, since most remote places are by definition harsh environments, a solenoid installed there should have sturdy building and be capable of withstand and operate at extreme temperatures whereas nonetheless maintaining the identical reliability and security capabilities required in less harsh environments.
When choosing a solenoid control valve for a distant operation, it is possible to discover a valve that does not compromise performance and reliability to scale back energy demands. Look for a high FFR, simple dry armature design, nice magnetic and warmth conductivity properties and robust construction.
Andrew Barko is the sales engineer for the Energy Sector of IMI Precision Engineering, makers of IMI Norgren, IMI Maxseal and IMI Herion brand parts for energy operations. He presents cross-functional experience in software engineering and enterprise growth to the oil, gas, petrochemical and energy industries and is licensed as a pneumatic Specialist by the International Fluid Power Society (IFPS).
Collin Skufca is the key account supervisor for the Energy Sector for IMI Precision Engineering. He provides experience in new enterprise development and customer relationship management to the oil, gasoline, petrochemical and energy industries and is certified as a pneumatic specialist by the International Fluid Power Society (IFPS).
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