Spring Energized Seals for Aerospace and Defense
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Spring-Energized Seals for Aerospace and Defense

In aerospace and defense applications, seals can be found in gearboxes, flap actuators, aircraft braking systems, actuators, turbopumps, cryogenic refueling systems, and hydraulic systems. They are necessary for land and ground defense systems, seaborne systems, ships, UAVs, airborne systems, and aircraft. But finding a sealing solution that provides the right mix of reliability and performance in the harsh environments associated with such applications can be challenging. However, there is a solution: spring-energized seals.

Spring-Energized Seals

Spring-energized seals are designed with a stainless steel spring designed to keep the seal lip in contact with the sealing surface despite wear, eccentricity, pressure changes, dimensional changes, and out-of-roundness. Spring-energized seals are often implemented when other sealing solutions have failed.

When the right jacket material is chosen, spring-energized seals can also handle some of the harshest operating conditions, including exposure to corrosive or reactive chemicals, extreme temperatures, wide temperature and pressure ranges, and environments where lubricants cannot be used.

The Challenges of Aerospace and Defense Sealing Solutions

Because both aerospace and defense applications are mission-critical, seal failure is simply not an option. Seal performance is key, even in extremely harsh environments that can destroy traditional polymer and elastomer seal solutions.

Many times, aerospace and defense engineers must achieve a balance between the friction of a seal and its sealing effectiveness. This can be difficult because friction increases power consumption which in turn can increase the fuel or power needed. A low coefficient of friction is a must for the seal jacket material used, especially if it is a dynamic seal of one that involves oscillating movements.

Applications that involve oscillation, such as pan/tilt, pod, and gimbal seals, must have both low friction but prevent stiction. Repetitive, precise, accurate movement has to be taken into account for some of these applications.

Aerospace and defense sealing environments often involve corrosive or reactive media that is not only dangerous if it leaks but can destroy the materials used for seals. Chemical compatibility and resistance to media such as fuels, oils, acids, bases, and other reactive chemicals is a must.

There is, however, another factor to be accounted for: abrasive media. Many seals are exposed to environmental contamination such as dirt, dust, sand, and other abrasive particles. An effective seal must not only be able to keep such contaminants outside, but not be destroyed in the process.

Extreme temperatures (and temperature ranges) can also pose a serious challenge. Applications can involve cryogenically cold temperatures down to -460°F to extreme heat at 600°F. And some operating environments may involve temperatures that vary widely, making dimensional stability a key element in seal design for aerospace and defense equipment. Temperatures are not the only environmental factor that can be extreme, however. Operating pressures can be extreme, ranging from 20 KSI to vacuum pressures.

Spring-Energized Seals for Aerospace and Defense

Spring-energized seals are highly reliable, even when things go wrong. They provide dependable performance in extremely harsh conditions, especially when the right seal jacket material is chosen.

Materials such as PTFE or PEEK have extremely low coefficients of friction and are self-lubricating. When combined with spring-energized seal design, the result is a low-friction seal that does not compromise the effectiveness of the seal and prevents potential issues with stiction and stick-slip behavior. These materials are also self-lubricating, making them ideal for situations where temperature or media rules out the use of traditional lubricants.

In addition, PTFE and PEEK are both highly resistant to chemical attack, with PTFE being the most chemically compatible polymer on the market. Combining the reliability of a spring-energized seal with the compatibility of materials such as PTFE or PEEK means a high performance seal that can survive in the presence of harsh media.

Spring-energized seals can account for seal wear and changes in the surface condition of the sealing surface without compromising the integrity of the seal. When combined with an abrasion resistant jacket material, they become an ideal sealing solution for applicants that involve abrasive media and contamination.

Both PEEK and PTFE can handle the extreme temperatures involved in aerospace and defense sealing applications. Not only do they possess a wide range for operating temperatures, they are also dimensionally stable. Dimensional stability combined with the ability of a spring-energized seal to account for dimensional changes make for an excellent sealing solution when there are extreme temperatures and wide temperature differentials involved.

Extreme pressures are another area where spring-energized seals outperform traditional seals. Whether its negative vacuum pressures or high 20,000 psi pressures, spring-energized seals can provide reliable performance — even when the environmental pressure varies significantly. Keep in mind that the spring-energizer keeps the seal lip in contact with the sealing surface.

Where Spring-Energized Seals Are Used

Spring-energized seals are already being used in landing gears, where they have proven invaluable for cylinders and hydraulic pumps. They offer the precision and performance needed for metering valves and fuel pumps, not to mention their use with actuators as they prevent environmental contamination. Spring-energized seals can also be found applications involving gimbals and pods, where their low coefficient of friction and self-lubrication prevents issues with sticking.

Conclusion

Spring-energized seals with PTFE or PEEK as the jacket material provide a high-performing solution to many sealing applications in the demanding environments of the aerospace and defense industries. Keep in mind that custom jacket profiles and spring-energizers can also be engineered to meet specific project needs and extensive testing can be performed to ensure that they are in compliance with related military standards.

Oil and Gas Industry During COVID-19
by Jackie Johnson Jackie Johnson No Comments

The Oil and Gas Industry During Covid-19

During the early months of 2020, when the COVID-19 pandemic raged across the globe, the oil and gas industry face a historic collapse.

2020 was a year of astounding disruption.

With restrictions in travel, decline in economic activity, a price war between various countries, and declines in stock, the industry was shaken to its very core and, like many other industries, forced to reinvent itself in the wake of 2020.

In this week’s blog post we will discuss the state of the oil and gas industry during the COVID-19 pandemic, how it has fared, and innovations that have been made.

An Industry Wide Crisis

2020 was a volatile year for many industries, oil and gas in particular. In the early months of 2020, oil prices had declined by about 33%. After that various oil producing countries engaged in a price war, triggered by a breakdown in dialogue. COVID-19 caused a historic drop in travel, causing the demand for oil to plummet to unprecedented lows.

WTI spot prices declined to as low as $8.91 a barrel in April of 2020, a level not seen since the economic recession of 1986. The drop in oil prices has also added problems to several energy producing states and local governments in the US, such as Texas, that are dependent on oil and gas revenue.

Many companies had to reorganize their entire business model, and many others were forced to file for bankruptcies or to liquidate their assets.

Things looked fairly bleak for the industry as 2020 progressed and the pandemic continued to rage across the globe. Despite that there were several silver linings.

Oil in the Medical Market

One good thing is that despite the disruption in oil production, causing a drop of more than a million barrels per day over the year, there has been little to no shortage in actual supply of oil. This means that people have still been able to fill their car or use natural gas to heat their home. The industry has also been open during large parts of the pandemic, having been deemed essential by the government. This makes sense, as petroleum is used in everything from anesthetics to wheelchairs to the gas the powers ambulances.

Likewise, while there has been a shortage of medical supplies such as masks and ventilators, it was mainly a planning issue. These supplies and others like gowns, surgical equipment, syringes and more are made with petroleum-based products. As such the oil and gas industry was able assist to manufacture all of those products in mere weeks to meet the demands created by COVID-19.

Similarly, with the COVID-19 vaccines include syringes made from plastics derived from petroleum, and the Pfizer and Moderna vaccine require storage in industrial refrigeration made possible thanks to petroleum-based products.

Digitalization

While there is no doubt that COVID-19 has disrupted the oil and gas industry, some are stating that it may be a blessing in some ways. According to a report by the International Bar Association, the “reduction in oil and gas prices has increased the pressure on the industry to seek greater efficiency and reduce production costs.”

One promising alternative is digitalization, either through virtual modeling for project optimization, digital planning, cloud-based process design or machine learning.

With the social distancing requirements in place in many countries, this has forced companies to streamline remote work platforms.

Bob Benstead, VP of business cloud software firm Infor had this to say on the subject:

“I believe the biggest development that the oil and gas industry will see in 2021 will be the dramatic ramp-up of digital initiatives. This will truly push the industry toward new thinking, especially around how to maximize AI and machine learning, aligned to sensors and other Internet of Things devices, to drive down costs and optimize the workforce. Additionally, the increased trend toward cloud computing will help to significantly lower the total cost of service (TCS) to build, run and maintain efficient ERP (enterprise resource planning) and EAM (enterprise asset management) systems that oil and gas companies rely on.” (Rigzone.com “What Looms for Oil and Gas in 2021”)

Digitalization is expected to play a key role in the oil and gas industry as 2021 goes on. With enabling remote operations and allowing more human-machine collaboration, digitalizing is driving the industry forward.

Hope on the Horizon

The EIA (the US Energy Information Administration) predicts that the cost of crude oil will decline by the second half of 2021, making a more balanced global oil market. This will hopefully lower gas prices, which have been at record highs, as well as lowering the cost of production of petroleum-based products.

The oil and gas industry is also looking towards the future, with key players looking into clean energy transition, exploring public-private partnerships.

In early October, 323 rigs were working in domestic oil plays, which rose to 413 for the week ended Dec. 23, up about 28% year to date. This is still down substantially from the 838 rigs active in early March, but up nearly 50% from the early-July low of 279.

And finally, while the oil and gas industry as a whole has seen a downturn in profit, one sector, the gas pump market, as seen a CAGR growth of 6.85% in 2020, and is expected to reach a market size of US$8.685 billion by the year 2026.

In Conclusion

The impact of COVID-19 on the oil and gas industry has forced many to discuss the future of one of the world’s most volatile industries. Despite the hardships, however, there is no doubt that oil and gas will remain an important part in the global economy, and our every day lives, for some time to come.

For more information of polymer sealing solutions for oil and gas, contact Advanced EMC Technologies today!