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If I had to estimate the number of times someone asked for a seal meeting AMS7287, the answer is very few. On the other hand, the number of times someone has asked for a seal material meeting Mil-R-83485, AMS-R-83485, MS83485 or AS83485 it would be too many to count. The lack of inquiries surrounding AMS7287 is surprising, given the document has been active since 2012. Therefore, if you are reading this blog and are familiar with the AMS-R-83485 specification, but do not know much about the AMS7287 specification you are not alone! This blog is intended to explain the differences and help you understand one specification with respect to the other.
But first, let me provide the title and status of each document as of April 2021:
table { font-family: arial, sans-serif; border-collapse: collapse; width: 100%; } td, th { border: 1px solid #6f6754; text-align: left; padding: 8px; } tr:nth-child(even) { background-color: #fdd880; } Number Title Status & Rationale Part Drawing & Numbering System Mil-R-83485 Rubber, Fluorocarbon Elastomer, Improved Performance at Low Temperature/td> Cancelled, S/S by AMS-R-83485 Mil-R-83485/1 M83485/1-xxx AMS-R-83485 Rubber, Fluorocarbon Elastomer, Improved Performance at Low Temperature Cancelled May 2014, S/S by AMS7287 (Ty I O-rings) AMS3384 (Ty 2 Molded parts) Mil-R-83485/1 M83485/1-xxx AMS7287 Fluorocarbon Elastomer (FKM) High Temperature / HTS Oil Resistant / Fuel Resistant Low Compression Set / 70 to 80 Hardness, Low Temperature Tg -22F (-30C) For Seals in Oil / Fuel / Specific Hydraulic Systems Active; Issued 2012-08 AS83485A M83485/1-xxx
Mil-R-83485 & AMS-R-83485 revisions
Looking at both Mil-R-83485 and AMS-R-83485, the document was largely unchanged in both requirements and intent. Qualification requirements included limits for:
Basic physical properties
TR-10 (Temperature Retraction) of -20°F
Compression set for 70 hours @ 75°F
Compression set for 22 hours @ 392°F
Dry Heat age of 70 hours in 528F air for a change in physical properties and weight.
Fluid Immersion in Fuel, 70 hours at 73°F for a change in physical properties and volume
*Long term Compression set for 166 hours @347°F (with the second set to cool for 18 hours in test fixture)
*Fluid Immersion in Di-ester polyol, 70 hours at 347°F for compression set plus a change in physical properties and volume
(*not carried over to AMS7287)
Over the years of “83485” revisions, there were some changes in the exact fluid called out, but the intent did not change. For example, TT-S-735 Type III was later updated to Fuel B which might appear to be a change, but both are a 70/30 blend of isooctane and toluene. Similarly, the Stauffer Blend 7700, a di-ester polyol synthetic-based oil, was updated to AMS 3021 (also known as Hatco 7700 and Service Fluid 101) which is basically the Mil-L-7808 oil, also a polyol synthetic-based oil.
An interesting detail about the specifications has to do with ownership and the subsequent naming convention. The documents with the ‘Mil’ prefix were owned by Wright Patterson Air Force Base, and when they turned ownership over to SAE, the document number prefix transitioned to “AMS”. This naming convention also explains why some of the fluids within the specification switched from a brand of di-ester polyol to a reference oil with an AMS prefix.
AMS7287 changes
The change to AMS7287 brought about more than a few changes to nomenclature and standardization of fluids. The testing criteria which stayed the same are the first six listed above for Mil-R and AMS-R-83485. The polyol oil immersion from the requirements was carried over, however, there is a difference to the fluid, the testing limits, and the addition of a compression set. The synthetic oil was updated to AMS3085, which is a reference lubricant for High Thermal Stability (HTS) oils such as Mil-PRF-36699(HTS), Mil-PRF-7808 Grade 4 and AS5780 Class HPC. This change makes sense given the widespread use of AMS-R-83485 seals in HTS oil applications such as gear turbine oils and engine oils. In addition, the AMS3085 type oil is standard among other SAE-owned specifications, such as AMS7257 and AMS7379.
Further technical changes from AMS-R-83485 to AMS7287 are the addition of the following requirements:
Glass transition temperature (Tg) of -20°F
Long Term Compression set for 336 hours @ 392°F
You may notice that the original list of requirements at the beginning includes a 166-hour compression set but at a more modest temperature of 347°F, with a maximum result of 25% on O-rings. The addition of a 366-hour test at a temperature 45°F higher is significant. Qualified materials must not exceed a compression set of 50%. This more aggressive condition could easily cause a material that meets the requirements of AMS-R-83485 not to meet the requirements of AMS7287.
Another area of change is with respect to conformance testing. The “83485” specifications require O-rings to undergo acceptance testing on size -214 O-rings molded at the same time as the production batch of O-rings. The move to AMS7287 requires testing on the actual O-rings unless they are an unsuitable test size. In the case of unsuitably sized O-rings, only then would the -214 O-rings be tested for physical properties and compression set.
The final area of significant change in AMS7287 is the requirement of each manufacturer to have their material approved and listed on the Qualified Producers List (QPL). This means each manufacturer must also be approved and listed on the Qualified Manufacturer’s List (QML). QML and QPL status require a robust quality system and rigorous audits by the governing body, which ensure both the material and the necessary manufacturing practices comply with the AMS7287 standard.
Parker’s VM125-75 fluorocarbon meets all the requirements of AMS7287. For more information on VM125 or the AMS7287 specification, please reach out to one of our Application Engineers, or click here to view test data and our product bulletin.
Article contributed by Dorothy Kern, applications engineering lead, Parker O-Ring & Engineered Seals Division
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Parker Chomerics has recently released THERM-A-GAP™ GEL 75, a 7.5 W/m-K thermal conductivity, single-component, dispensable thermal interface material. THERM-A-GAP GEL 75 is the latest from the THERM-A-GAP family of dispensable thermal materials from Parker Chomerics to be released to the market.
When applied to a heat generating component, THERM-A-GAP GEL 75 provides minimal stress and pressure due to its low compression force. It is form stable in horizontal or vertical applications and allows for lower assembly costs when compared to multiple thermal gap pads in higher volume applications.
3x faster flow rate, highest thermal conductivityTHERM-A-GAP GEL 75 represents the highest thermal conductivity dispensable available from Parker Chomerics. With a flow rate of 30 grams per second, it is nearly 3x faster than the next closest performing material in the THERM-A-GAP family.
The gel-like consistency enables superior performance and long-term thermal stability and is designed to be dispensed in applications requiring low compressive forces and minimal thermal resistance for maximal thermal performance.
Superior, reliable performance in the fieldParker Chomerics has conducted a detailed examination of the thermal reliability of this high-performance gap filler after being subjected to long-term environmental aging under dry heat, heat and humidity conditions, and temperature cycling from -40°C to 125°C.
The thermal performance of THERM-A-GAP GEL 75 was examined, and the findings were reported in the THERM-A-GAP GEL 75 Reliability Report TR1104. After being subjected to multiple environmental stress tests, the thermal impedance of the aged samples did not experience a significant increase after any of the treatments studied.
After a 1,000-hour dwell at 125°C, 1,000 hours at 85°C/85% relative humidity, and 1,000 temperature cycles from -40°C to 125°C, there was no statistically significant increase in impedance according to one-way ANOVA with the Tukey method for multiple comparisons.
NASA outgassing resultsThe National Aeronautics and Space Administration (NASA) criteria for low-volatility materials limits the total mass loss (TML) to 1.0% and collected volatile condensable material (CVCM) to 0.10%. Outgassing results for GEL 75 are 0.18% TML and 0.05% CVCM. Independent laboratory results indicate THERM-A-GAP GEL 75 passes the NASA outgassing criteria for low-volatility material.
Based on these results, THERM-A-GAP GEL 75 demonstrates the ability to withstand long-term aging without a reduction in thermal performance. THERM-A-GAP GEL 75 is best suited for high volume, automated production, specifically found in telecommunication applications, base stations, power supplies, and memory and power modules.
Learn more about THERM-A-GAP GEL 75 and receive a free product sample.
This blog post was contributed by Jarrod Cohen, marketing communications for Parker Chomerics.
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In the Oil & Gas industry, the need for elastomers to seal higher pressures for sustained periods of time with minimal damage is abounding. Applications such as drilling tools, completions equipment, blow out preventers, and subsea pressure control systems now routinely require or exceed 15,000 psi with both liquid and gas media for functional testing and qualification. Parker meets this challenge, providing a best-in-class extrusion and rapid gas decompression resistant hydrogenated nitrile (HNBR) compound called KB292.
One of the most common failure modes for seals utilized in high pressure applications is known as extrusion or nibbling. This failure method emerges when the seal material is forced into a clearance gap that is present between the mating substrates and gradually can be cut, nicked, or chewed away. Typical applications which can see this transpire include dynamic reciprocating cylinders and/or vessels where pressure fluctuations cause clearance gap to open and close trapping the seal between mating surfaces. The higher the pressure or the larger the clearance gap that is present, the more likely extrusion or nibbling is to occur. Once a mass of the material is removed from the seal geometry it is inevitable that a leak will eventually form which normally results in failure of the system. Section 10 of the Parker O-Ring Handbook highlights extrusion and nibbling as well as includes several suggestions for prevention.
Another failure mode which can be seen for high pressure gaseous applications is known as Rapid Gas Decompression (RGD), also referred to as Explosive Decompression (ED). This damage arises after a period of service under high pressure gas, when pressure is reduced too rapidly, the gas trapped within the internal structure of the seal expands rapidly, causing small ruptures or fissures to develop. There are many Oil and Gas industry standard tests which have been developed to determine whether compounds are RGD resistant. Parker routinely tests and acquires certificates for these standards which can be supplied upon request for end user documentation. Our Oil & Gas Reference Guide outlines our numerous materials, temperature ranges, recommended uses, and a list of approved certifications by material. 
To combat seal damage and the typical failures in high pressure applications, Parker has developed material KB292. This hydrogenated nitrile (HNBR) based material has been formulated with physical properties which allow it to withstand exposure to the highest-pressure environments with extreme extrusion resistance. With hardness of 95 +/- 5 Shore A points, KB292 is one of the hardest elastomers in the Parker OES material offering. The extreme extrusion resistance is also identified with a modulus value of 2500psi at 50% elongation as well as excellent abrasion and tear resistance. The material offers good compression set and chemical resistance that is expected from all Parker HNBR’s used in the O&G industry. Additionally, Parker's KB292 has been tested to and passes the requirements of ISO 23936-2 RGD which shows excellent resistance to explosive decompression for high pressure gas applications.
For more information about the KB292 compound, reference Parker’s OES 7003 technical bulletin or chat live with an applications engineer by visiting our website.
Nathaniel Sowder, business development engineer, Parker Hannifin O-Ring & Engineered Seals Division
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Robotic surgery systems or robot-assisted surgery, offer immense patient benefits -- from shorter recovery time, to better surgeon visualization, which leads to a more precise, effective and successful surgery. Robot systems are used for various surgical procedures, including urologic, gynecologic, cardiothoracic, general, and head and neck surgeries. Manufacturers and designers of these surgical systems are now focusing on robot specialization instead of all-encompassing surgical systems.
This means there will be more specialized systems developed to perform specific surgeries, and the breadth of those procedures is expanding too. General surgery uses are increasing the fastest, followed by gynecology and urology uses. In 2017, there were 877,000 robotic surgeries performed in the US alone. That number is expected to rise exponentially in the years to come.
Any medical device that employs onboard electronics can be impacted by EMIRobotic surgery system manufacturers and engineers consider EMI shielding when designing their systems. EMI shielding prevents equipment failure and keeps manufacturers compliant with federal regulations. Understanding EMI and taking steps to prevent it is paramount, as the resultant issues could cause robots to behave unexpectedly, such as requiring frequent restarts, showing a limited radio frequency range, moving unintentionally or affecting other nearby robots.
Remember, EMI is when electromagnetic emissions from a device or natural source interfere with another device or system. EMI might occur if the following three factors are present — the source of EMI, a coupling path and a receptor.
The coupling path from the source to the receptor can be either an electric current, magnetic field or an electromagnetic field. The EMI source can be a natural source, such as lightning. It can also come from devices such as radios, computers, wireless networks, cell phones or any electric device designed to transmit signals.
Robotic surgery systems are computer controlled, and therefore sensitive electronic components must be shielded from electromagnetic interference (EMI) and generated heat must be effectively dissipated from various integrated circuits (ICs). On top of these stringent requirements, components must be able to withstand high heat sterilization, and resist damage caused by harsh chemical cleaning agents in the hospital environment.
Discover the top four EMI shielding and thermal interface material applications for robotic surgery systems
With proven solutions in EMI shielding and critical thermal management, Parker Chomerics gives you a wealth of integrated, multi technology systems and components that meet or exceed your specifications and expectations.
This blog post was contributed by Jarrod Cohen, marketing communications for Parker Chomerics.
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Have you been frustrated with going through multiple design iterations when rubber components are failing due to high stresses or your device has been leaking due to insufficient compression? Have you lost months and months of precious time having to recut tools and make design changes?
FEA takes out the guesswork
Finite element analysis (FEA) is an effective tool used in design iterations. It allows for different design ideas, options, and alterations to be quickly, effectively, and precisely compared.
Using FEA can improve both the speed and quality of product design as well as reduce the overall cost. Rubber parts, such as silicone diaphragms, septums, seals, valves, tubing, and balloons are critical components in today’s medical devices that can benefit from the use of FEA. It can be an excellent design tool to improve the functional performance of these devices. FEA for rubber products is actually far more complex than for metal or plastic products. It requires sophisticated nonlinear FEA software - such as MSC Marc - as well as a good understanding of the material behavior, material modeling, and testing requirements.
Rubber is highly stretchable, flexible, and durable. This blend of elastic properties differentiates rubber from other materials and makes it one of the best choices for many components in medical devices. However, it’s important to note that rubber materials are not 100 percent elastic because they can develop compression sets and force decay, causing eventual performance degradation and shorter useful life.
Nonlinear FEA for rubber products
Normally, there are three types of nonlinearities encountered: kinematic nonlinearity, material nonlinearity, and boundary nonlinearity. Additionally, rubber products are often subject to large deformations. Whenever material experiences large deformations at least two kinds of nonlinearity - kinematic and material - are involved.
Commonly used nonlinear material models in FEA are elastoplastic models for metals and plastics and hyperelastic models for rubber. in addition, the boundary nonlinearity is usually associated with large deformations.
What are the best test modes to use? One basic engineering rule should apply: always design and perform tests that most closely simulate the actual application conditions that the finished component or device will experience.
Rubbers are almost incompressible
In general, rubber materials are considered nearly incompressible, simply because their volume change is negligible for most applications as a result of that their bulk modulus (105 psi) being several orders larger than their shear modulus (102 psi). The rubber material is actually much more compressible than metal in a confined state (the bulk modulus of typical steel is 107 psi). This understanding is very important to the design considerations of elastomeric products, especially when thermal expansion, limited groove space, or compression of high aspect ratio parts are involved.
Simulation accuracy and relativity
Many factors affect the accuracy and reliability of FEA results, such as material modeling, geometry simplification, and numerical methods. FEA is mostly used in design iterations for which relative comparison is sufficient in the majority of instances. When analysis results are interpreted in a relative sense, different design ideas, options, or modifications can be compared effectively and accurately, and most importantly, rapidly. Furthermore, some tested cases may already exist and can be used as references.
FEA improves product design
FEA is a powerful tool for the development of rubber components for medical devices. The proper use of FEA can minimize physical prototyping and provide for concurrent engineering. It greatly improves both the speed and the quality of product design, as well as provides cost savings.
Parker has more than 20 years of testing experience with FEA. For more information on Parker‘s use of FEA watch our detailed video - Accelerating Your Launch: Reducing Design Iterations with FEA.
Check out all of our Sealing solutions for Life Science applications including featured applications for Diabetes Care, Surgical, Respiratory, Drug Delivery Systems, and more!
This post was contributed by Albena Ammann, life science development engineer, Engineered Materials Group, Parker Hannifin.
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In our recent webinar about electrically conductive sealants and adhesives, our experts covered many topics from electrically conductive filler packages to the physical properties of the materials like adhesive strength, flexibility and working life. Did you miss Introduction to Electrically Conductive Sealants and Adhesives? Watch it now.
The viewer learned the difference between an electrically conductive sealant and an electrically conductive adhesive, why you’d choose one over the other, and the design considerations you need to take now.
During the Q&A portion of the webinar, our experts fielded your excellent questions, so we’ve rounded up our eight top favorites for you below.
Did you miss this webinar, or maybe want to watch it again? Watch it for free on-demand now. And so you don’t ever miss another, be sure to sign up for our upcoming webinars.
This blog was contributed by Jarrod Cohen, marketing communications manager, Parker Chomerics.
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Improvements to a drug delivery system (DDS) can control the consistency and increase the quality of drug delivery. Parker’s self-sealing polyisoprene is designed to improve on existing systems available in the market. Parker’s USP <381> self-sealing polyisoprene elastomers demonstrate exceptional self-sealing capabilities, even with needles as large as 16-gauge. Due to the minimal force required for piercing, our material is ideal for seals and septa used in infusion systems and insulin pumps. Using our USP <381> polyisoprene material may improve septum performance and user safety for doctors, nurses, and patients.
The advantages of self-sealing
A needle, as large as 16-gauge, can pierce the polyisoprene septa as many as 20 times with no trace of leaks. Good self-sealing properties ensure that when the needle comes out, the drug stays in. Our self-sealing polyisoprene is non-coring. After piercing, there is no visible fragmentation and therefore no tiny pieces to clog the system or contaminate the fluid. This is important to maintaining the purity of the drug throughout the delivery process and ensuring a safe transfer to the patient.
Parker’s self-sealing polyisoprene meets USP <381> standards for the functional testing of closures intended to be pierced by a needle. It also meets biological testing as defined by USP <88> and USP <87> for in vitro and in vivo testing, respectively. Our self-sealing polyisoprene passed the biological reactivity and systemic injection tests. The material is biocompatible and has shown no harmful reactions or toxic effects.
Using Parker’s self-sealing polyisoprene for seals and septa in insulin pumps and infusion systems provides improved performance, ease of use, and increased safety due to elimination of leaks and reduction of blockages. This pioneering material allows medical staff to have seals and septa that can be pierced multiple times during use with no leaks. The development of this new product is an exciting prospect for the drug delivery market.
Our facilities are located near major cities to enable easy distribution. Contact us for more information on how we can improve reliability with your drug delivery system.
This article was contributed by Saman Nanayakkara, Engineering Manager, Parker Hannifin Composite Sealing Systems Division.
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Mitigating the contamination risk in biopharmaceutical manufacturing is essential for two reasons: Obviously, product safety for patients is of paramount importance, but manufacturers must also be protected against substantial financial losses, resulting, for instance, from a necessary destruction of their highly valuable product due to in-process contamination.
Benefits of single-use solutions in combination with overmolding technology
For effective and cost-efficient mitigation of contamination risks within the process chain, Parker Prädifa offers an extensive portfolio of “intelligent” and customizable solutions for a wide range of applications in upstream and downstream processes using advanced, proprietary overmolding technology.
Thanks to the open architecture the fully scalable technology spectrum enables the integration of previously validated components such as tubing. This considerably helps reduce overall system costs and offers a closed, tamper-proof system for protection of the product.
Every single-use solution is precisely adapted to the previously validated production framework and offers substantial overall system cost reduction potential.
Securing the supply chain
Manufacturing, assembly and packaging processes in certified clean rooms are a basic prerequisite for serving pharmaceutical and biopharmaceutical customers. In Europe, Parker Prädifa operates two clean room production facilities: one in Sadska (Czech Republic) certified according to ISO 14464 Class 7 and one in Pleidelsheim (Germany) certified according to ISO 14464 Class 8.
Additional information:
Posted by Dr. Heinz-Christian Rost, market unit manager life sciences, Engineered Materials Group Europe, Prädifa Technology Division
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When designing a gland in which an O-ring or elastomeric seal is the desired sealing component, there are several aspects that need to be considered. A perfectly designed seal with the right material, ideal compression, gland fill and stretch can have inadequate sealing capability if the surface finish of the hardware is neglected. This blog discusses the ideal surface finish requirements for both the application and testing of seals.
Consider these photos of metal surfaces. At first glance, all three may appear to be identical, but looking closely, the main difference is surface finish. Figure 1 illustrates the appearance of surface finish as it will be discussed.
Figure 1: Left to Right: 500x magnification of 16µin RMS, 32µin RMS, 63µin RMS
Surface finish, as pertinent to seal design, is the measurement of the roughness of the two hardware faces compressing the O-ring or seal. That is why it is sometimes referred to as “surface roughness” as well as surface finish. Maintaining proper surface finish of these two surfaces is essential to obtaining a good seal. Table 1 outlines the basic guidance suggested in the ORD 5700 O-Ring Handbook.
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The requirements for sealing gas and vacuum are more restrictive than a liquid due to gas’s ability to find passage through very minute pathways on a hardware surface. Some estimates are that the viscosity of air is 53x to 55x less than that of water, which equates to about 53x more volume of air passing through the hardware indentation than water would.
For static seals, Parker recommends using a surface roughness value not to exceed 32 µin (32µin RMS) when the seal involves liquid and a maximum of 16µin RMS when the seal involves gas.
If a surface is too rough against a static seal, the O-ring may have difficulty conforming to surface imperfections causing leakage. Durometer of material can play a role in overcoming surface finish. The softer the material, the more it will fill in the peaks and valleys of the sealing surface, however, this may be at the detriment of other sealing properties, such as contact pressure, compression set resistance, extrusion resistance, or durability.
For static sealing, consideration of the method used to produce the surface finish can certainly play a role and potentially offer improved sealing margin. Methods such as lathe or some other machining technique that produces tool marks parallel to the groove can be sealed most effectively and in certain situations may seal at roughness values greater than recommended. Other methods, such as end milling or routing, produce tool marks perpendicular to the groove and may be too deep for the O-ring to make full contact which could result in a leak path. In this situation, the recommended roughness values should not be exceeded.
For dynamic seals, the shaft or bore should have a surface finish between 8µin and 16µin RMS. This range of peaks and valleys on the hardware serves the purpose of holding the lubricant against the O-ring and ultimately minimize friction and wear damage.
Surface finishes above 20µin will cause abrasion on the O-ring surface, and no amount of lube will prevent the O-ring from wearing. Surfaces which are better than 10µin will result in the lubricant being wiped away, which thereby increases friction and accelerates wear over the life of the seal.
Figure 2 Illustration of mismatch on a molded component.
Questions come from customers with respect to hardware mismatch, surface porosity, and air or helium testing. Each of these questions often simplify down to the same guidance which has been outlined above. Figure 2 illustrates the mismatch that can be present on a molded housing. While there is not a hard and fast rule for overcoming mismatch, application experience has found success with limiting the step to a maximum of .003”. Like mismatch, surface porosity is another application specific hardware challenge that can be difficult for a seal to overcome. A general rule of thumb is for the maximum porosity size to be less than half of the contact width of the compressed seal in the least material condition. Lastly, a seal designed to contain fluid which is failing an air leak test often has the root cause of leakage due to surface roughness. This comes back to the reality that air and gas are a much more difficult sealing medium than a liquid and a smoother surface finish can often improve this condition. In some instances, mismatch and surface porosity can be overcome with a custom designed seal, but it will not be possible for a custom designed fluid seal to pass a gaseous leak test when the surface finish is the cause of leakage.
If you have additional questions about surface roughness, please visit our website and chat with our support team or reach out to one of our application engineers at OESmailbox@parker.com.
Dorothy Kern, applications engineering lead, Parker O-Ring & Engineered Seals Division
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If the words “Fire Seal” bring to your imagination a Sea World show gone terribly wrong, then you probably won’t be interested in this blog. But, for anyone associated with the field of aviation, you’ll recognize a crucial element of aircraft safety. Fire Seals are barriers located within an aircraft nacelle that, in the event of an engine fire, work to keep it contained within the immediate area and deny it the oxygen it needs to propagate. This provides the opportunity to safely shut down the engine or APU.
Aircraft engine safety
Few things worry the cautious traveler more than the idea of an aircraft engine fire. After all, it’s not like you can pull over 6 miles above the ground and call Triple-A. But, the reality is that without fire, a flight would be impossible. It is the controlled burn of fuel within the engine that generates the thrust necessary for flight. So, what those burdened with ensuring aircraft safety focus on is the prevention, detection, and suppression of unwanted engine fire. To combat this, aircraft are designed with redundant systems for fire detection which alert the flight crew to engage in appropriate countermeasures. These include cutting off fuel to the compromised engine and activating fire extinguishers. These are examples of active measures for fire control.
Fire seals fall into the category of passive systems. Passive systems are always in place and require no external engagement to function.
Fire seals typically feature a composite structure. A flame-resistant elastomer is layered with a fire-resistant fabric which helps to maintain the structural integrity of the seal for a specific period of time. Typical materials used are silicone, aramid fabrics, ceramic, or other inorganic fabrics. Seals are typically molded for finite lengths (typically < 12 feet long) and can be spliced to meet longer length requirements or irregular geometries. Intricate custom shapes are possible employing salt core molding techniques.
Typical configurations include:
P-seals
Bellows
Diaphragms
Omega seals
Gaskets
Custom shapes
The main specifications governing fire seals are ISO 2685 and AC20-135. These documents define the test methods and acceptance criteria for evaluating seal performance. Seals are evaluated by their ability to survive exposure to a 2000 degree flame for a specified period of time. Components can be classified as either fire-resistant (5 minutes) or fireproof (15 minutes).
Parker's Engineered Materials Group supplies fire seals through our Composite Sealing Systems Division (CSS), headquartered in San Diego, CA. Our seals have been tested by a third-party laboratory and have been proven to meet the requirements of the governing specifications. Testing consists of exposing a production-representative component to a set of application-specific conditions that may include pressurization, airflow, and vibration, all while exposed to a calibrated 2000°F flame. The component must not allow any burn-through during the entire test and should not self-ignite after the burner is removed.
Parker is a major supplier to many major aerospace OEMs. To learn more about how we can help support your production, reliability, and safety goals, contact us.
Learn more by watching our video on all our sealing solutions for aerospace.
Article contributed by Brian Alessio, business development engineer, Engineered Materials Group, Parker Hannifin.
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