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Advancements in Aerospace Dynamic Seals: Enhancing High-Temperature Capabilities for Aerospace Applications

Aerospace engineering has always been at the forefront of technological innovation, pushing boundaries to achieve unprecedented aviation and space exploration milestones. One area that plays a crucial role in ensuring the safety and efficiency of aerospace systems is dynamic sealing technology.

Dynamic seals are essential to prevent fluid leakage, maintain pressure differentials, and protect sensitive equipment from external contaminants. Traditional sealing solutions often fall short in the challenging environment of aerospace applications, where extreme temperatures and pressures prevail to catch up. However, recent advancements have led to the development of dynamic seals with enhanced high-temperature capabilities that are revolutionizing the aerospace industry.

aerospace dynamic seals

This article delves into these cutting-edge advancements in aerospace dynamic seal technology. We explore how these seals overcome challenges posed by high temperatures, discuss their benefits for various applications within the industry, address frequently asked questions regarding their performance and reliability, and analyze their impact on future developments.

The Need for High-Temperature Capabilities

In aerospace applications such as jet engines or rocket propulsion systems, temperatures can reach staggering levels due to combustion processes or atmospheric re-entry conditions. Traditional sealing materials like elastomers or certain rubbers fail under extreme circumstances due to degradation or melting at elevated temperatures.

There is a dire need for dynamic seals capable of withstanding high temperatures without compromising functionality or integrity to ensure optimal performance and safety even under these harsh conditions. Fortunately, recent advancements have paved the way for innovative sealing solutions that address this critical requirement.

Advancements in Material Science

One key aspect driving advancements in aerospace dynamic seal technology is material science. Researchers have been exploring new materials with improved thermal stability and resistance to degradation at elevated temperatures. These advanced materials exhibit excellent mechanical properties, low friction coefficients, and high wear resistance, making them ideal for aerospace applications.

High-Temperature Resistant Polymers

Polyimides and perfluoro elastomers (FFKM) are high-temperature-resistant polymers that have gained significant attention in the aerospace industry. Polyimides possess exceptional thermal stability and can withstand temperatures up to 500°C (932°F), making them suitable for critical sealing applications in aircraft engines or space propulsion systems.

FFKM, on the other hand, combines the chemical resistance of perfluoroelastomers with high-temperature capabilities. With an impressive upper-temperature limit of around 320°C (608°F), FFKM seals provide reliable performance even in extreme environments where traditional elastomers would fail.

Ceramic Matrix Composites

Another promising material category for aerospace dynamic seals is ceramic matrix composites (CMCs). CMCs offer a unique combination of lightweight design and exceptional thermal properties. These materials consist of ceramic fibers embedded within a ceramic matrix, providing enhanced strength and thermal resistance compared to conventional ceramics.

CMCs can operate at temperatures exceeding 1600°C (2912°F) without significant degradation, making them ideal for sealing applications subjected to extreme heat. Using CMCs in dynamic seals ensures longevity and reliability under demanding conditions while reducing weight and improving overall system efficiency.

Innovative Seal Designs

In addition to advancements in material science, innovative seal designs have played a vital role in enhancing high-temperature capabilities for aerospace applications. Traditional radial lip seals or O-rings often must be improved to withstand extreme temperatures or pressures encountered during flight or space missions.

To overcome these limitations, engineers have developed novel seal designs tailored explicitly for high-temperature environments:

Spring-Energized Seals

Spring-energized seals are engineered with a metal spring core encased within a polymer jacket. This design ensures optimal sealing performance even at high temperatures and pressures. The spring provides the necessary force to maintain a tight seal, while the polymer jacket is a barrier against fluid leakage and external contaminants.

These seals are highly versatile and find applications in various aerospace systems, including fuel pumps, hydraulic systems, or cryogenic equipment. By incorporating advanced materials such as polyimides or FFKM, spring-energized seals offer exceptional resistance to thermal degradation and ensure reliable operation under extreme conditions.

Metal C-Ring Seals

Metal C-ring seals are widely used in aerospace applications due to their superior resilience and ability to withstand high temperatures. These seals feature a metallic ring with an asymmetrical cross-section that allows for efficient sealing when compressed between mating surfaces.

The metal C-ring design offers excellent recovery properties after compression and exhibits minimal leakage even under extreme temperature differentials. It finds extensive use in turbine engines, exhaust systems, or other critical areas where reliable sealing is paramount.

Benefits of Enhanced High-Temperature Capabilities

The advancements in aerospace dynamic seal technology have brought forth numerous benefits for the industry:

  1. Improved Safety: These advanced seals enhance safety standards within aerospace systems by ensuring reliable sealing at high temperatures.
  2. Extended Component Lifespan: Withstandability of extreme temperatures enables longer lifespans for critical components like engines, reducing maintenance costs.
  3. Enhanced Efficiency: Advanced dynamic seals minimize fluid leakage and improve system efficiency by maintaining optimal pressure levels.
  4. Weight Reduction: Using lightweight materials such as CMCs reduces overall component weight without compromising performance or safety.
  5. Versatile Applications: Aerospace dynamic seal technology finds applications across various sectors like commercial aviation, military aircraft, and spacecraft propulsion systems.

Aerospace dynamic seal technology advancements have revolutionized the industry’s approach toward sealing solutions that withstand extreme temperatures encountered during flight or space missions. Through innovative materials like polyimides, FFKM polymers, and ceramic matrix composites (CMCs), engineers have successfully overcome challenges associated with thermal degradation and improved seal performance under harsh conditions.

These enhanced high-temperature capabilities offer a range of benefits, including improved safety standards, extended component lifespans, enhanced system efficiency, weight reduction through lightweight designs like CMCs, and versatile applications across various sectors within the aerospace industry. As research continues toward achieving even more significant advancements in this field, we can anticipate further breakthroughs that will shape the future of aerospace engineering.

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HPLC Spring Energized Seals

HPLC spring energized seals

High-performance liquid chromatography is the ideal method for analyzing various solutions in different fields. This machine, however, requires HPLC spring energized seals that adhere to strict guidelines with slight variation.

Different Liquid Chromatography Types

There are a few different types of liquid chromatography. The primary liquid chromatography types include high-performance liquid chromatography (HPLC), preparative HPLC, and ultra-high-performance liquid chromatography.

High-performance liquid chromatography is used in multiple different industries. HPLC is found in food science, drug development, and forensic analysis. It is used to separate compounds and used for quantitative and qualitative analysis.

Preparative HPLC is used in purification applications as it requires a higher flow rate. This liquid chromatography is also used to separate and collect high-purity compounds. It is also used for large quantities of compounds needed for evaluation and analysis.

Ultra-high-performance liquid chromatography (UHPLC) is similar to HPLC. It is used to separate different constituents of a compound and to identify and quantify the different components of a mixture. 

Operating Conditions

HPLC pumps operate in conditions with variable flow rates and small shaft diameters. They have tight leak criteria and operate under a wide range of pressures. HPLC pumps have a medium-speed reciprocation.

Seals in HPLC pumps must withstand the solvents used to separate compounds dissolved in the liquid sample. Solvents used in HPLC include 

  • MeOH (Methanol)
  • ACN (Acetonitrile)
  • H2O (Water).

The expected lifetime for seals in HPLC pump environments is a minimum of one million cycles. Seals may last longer depending on the flow rate, pressure, and media.

Seal Designs

HPLC seals prevent leaks from occurring. Should the mile phase lack into the back of the pump, it will impact consistency, accuracy, and pump precision. To effectively prevent leaks, seals should have effective leak resistance in pressures up to 20 kpsi.

Seal Geometry

The geometry of the seal is an important factor. For HPLC pumps, a flange design helps reduce the pump’s pulsation. HPLC spring energized seals have a longer seal ID lip and a polymer backup ring to increase the amount of contact stress.

UHPLC seals have a non-flange design and a shorter seal ID lip. Instead of a polymer backup ring, it uses a ceramic or metal backup ring. These seals have a concave back for higher-pressure distribution.

Jacket Materials

HPLC pumps’ seals have a PTFE or UHMW PE jacket. The UHMW PE material is used in systems with pressures greater than ten kpsi. UHMW PE is an FDA-compatible material for both food and pharmaceutical analysis.

PTFE jackets are the most chemical resistant of the common materials. The PTFE jackets are filled with graphite or polyimide. These fillers are heat and wear-resistant and work well in liquids and steam.

Performance Factors

Sealing performance factors are affected by the different surfaces in the HPLC pump. The housing surface has a suggested static sealing surface between 9.1 to 14.5 μin Ra.

On the plunger surface, a smoother surface is best. For virgin PTFE or UHMW PE, a minimum shaft hardness is 40Rc. The suggested dynamic surface is 7.3 – 14.5 Ra μin.

 

Medium Dynamic Surface Static Surface
Reciprocating Rotary
RMS  Ra μin  RMS Ra μin  RMS Ra μin 
Liquids 8 to 16 7.2 to 14.4 8 to 12 7.2 to 10.8 16 to 32

14.4 to 28.8

Plunger alignment needs to have a minimal shaft-to-bore misalignment with tight concentric guidance between the wash body and pump head. For best sealing performance, the shaft-to-bore misalignment should be kept to a minimum. 

Shaft To Bore Misalignment at the Seal Area
Shaft Diameter (in inches) Shaft to Bore Misalignment (in inches)
0.000 – 0.750 0.0020
0.751 – 1.500 0.0025
1.501 – 3.000 0.0030
3.001 – 6.000 0.0035
6.001 – 10.000 0.0045

 

HPLC Spring Energized Seal Recommendations

The HPLC spring energized seal requirements should be considered during the pump design process. Designers should collaborate with seal engineers early in development. Contact us today to get a quote on your next custom seal needs. 

 

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Teflon PTFE Seals for Static and Dynamic Sealing

Advanced EMC Technologies’ Teflon PTFE seals are one of their frontline products, in continuous demand across many industries. The seal offers perfect static and dynamic sealing for the most demanding applications. Other key features include low friction, chemically resistant, dry/lubricated running used in many industries such as fluid handling, semiconductor, aerospace and instrumentation..

Talking about it, a senior executive with the company said, “The component is an integral part of the equipment across industry sectors. It can withstand extreme temperature, chemicals and pressure. Sealing jacket is made of resilient PTFE and can be energized by an internal spring when needed which applies a load to the sealing element at low pressures. It has unlimited shelf life and controlled friction/load.”

Spring energized seals have a resilient seal jacket and compensates for jacket wear, hardware misalignment or eccentricity. Polymer seal jackets materials include Virgin PTFE, Carbon/Graphite PTFE, Moly/Filled PTFE, Glass/Moly PTFE, Polyimide/Filled PTFE, UH/Polymer PE, 60% Bronze / filled PTFE and PCTFE / KEL F. FDA approved low friction Virgin PTFE is excellent for light duty service, cryogenic applications and low molecular weight gas service.

Carbon/Graphite PTFE offers superb resistance to heat and wear. Good in liquids and steam, it is recommended for dry or semi-dry applications. The executive added for Glass/Moly PTFE, “It works well for high pressure applications and is impressive in hydraulic, steam and water. The material is abrasive in rotary service against soft metals.”


Teflon Spring Energized PTFE Seals by Advanced EMC by PTFEseals

Polyimide/Filled PTFE seals are outstanding in dry service with low wear rate in vacuum and inert gases. It has very low abrasion to dynamic mating surfaces. UH/Polymer PE has higher friction than PTFE compounds. Static and slow dynamic PCTFE / KEL F is best grade for cryogenic applications. 60% Bronze / filled PTFE excels at very high rotary speeds with low pressure.

About Advanced EMC Technologies

Advanced EMC Technologies is an acclaimed company offering industrial grade polymer seals and bearings. The company deals in PEEK polymer seals, spring energized Teflon seals, PTFE rotary shaft seals, polymer bearings and bushings, precision components, nylon bushings and several other such products. The company provides quality products to meet budget and service expectations to clients.

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Sealing Solutions for Aerospace Industry

The aerospace industry needs robust sealing solutions, ever reliable and highly engineered. They need technologically advanced sealing devices that can withstand aggressive chemicals, variegated pressures and high temperatures. Top standard sealing products combine experience, engineering and innovation. These are cost effectively, yet efficiently built, to fit virtually any aerospace application. Read more

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Advanced EMC – Offering High PV Grades, FDA Compliant PTFE Seals

Businesses in Texas needing chemically resistant, low friction static and dynamic sealing solutions can procure these from Advanced EMC Technologies. They produce high grade FDA compliant PTFE seals that can withstand extreme temperature and pressure.

An executive with the company threw more light on the feature saying, “As the system pressure raises enough to take over from the spring and engage the shaft an ultra-efficient seal is created. The spring of the spring energized seal provides permanent resilience to the seal jacket compensating for jacket eccentricity, wear and hardware misalignment.”

Other salient features of the seals are fluid handling, high PV grades, unlimited shelf life, controlled friction/load and FDA/USDA compliance. The seals are efficient in dry running or lubricated, cryogenic and HPLC applications. They can effectively be used across sectors like medical and defense, medical, biomedical, food service, oil & seismic transportation and pharmaceutical. Polymer seal jacket are made of varied materials like virgin PTFE, carbon/graphite PTFE, moly/filled PTFE, glass/moly PTFE, polyimide/filled, UH/polymer PE, 60% bronze/filled PTFE and PCTFE/ KEL F.

FDA approved Virgin PTFE are known for low friction and light duty service. The executive elaborated, “1000 Fluorolon Virgin PTFE seals are excellent for cryogenic and low molecular weight gas service. It can withstand temperature range of -320 to 450F. Extrusion resistance and friction rating is lowest. Carbon/Graphite PTFE 1034 Fluorolon jacket seats, on the other hand offer excellent resistance to heat and wear. It is recommended for dry or semi-dry apps. It can stand temperature ranges of -320 to 500F. Extrusion resistance is moderate and friction rating is low.”

1017 Fluorolon Moly/Filled PTFE seals are excellent in dry gas with better wear resistance. Temperature range is -320 to 525. Extrusion resistance is very high and Friction rating is low. 1050 Fluorolon Glass/Moly PTFE seals offer superlative wear and heat resistance. These are abrasive in rotary service against soft metals and effective in high pressure applications. It is meant for temperature ranges of -250 to 550F, have very high extrusion resistance and moderate friction rating.