Category Archives: Parker Hannifin Seals

Learn more about Parker Hannifin seals, o-rings, polymer springs and much more in this collection of articles. Parker sealing products are used in a number of industries for a variety of applications, including hydraulic sealing systems.

Sealing Solutions for Drinking Water and Service Water Systems

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Dr. Stefan Reichle, Market Unit Manager, Engineered Materials Group Europe.


picture of drinking waterWherever drinking water is obtained from any of its sources, pumped and processed, materials with low extraction levels and without any harmful ingredients are required. Sealing compounds for use in drinking water and heating applications are subject to diverse approval regulations. These regulations serve to assure the safety of water from the time of intake, via treatment, processing and transportation through to the consumer. Practically every country in the world has its own drinking water regulations specifying particular tests and including lists of approved ingredients. These regulations are complemented by physical and microbiological examinations.

The Parker Engineered Materials Group has developed a number of compounds, each of which meets a wide range of the required approvals, thus permitting the global utilization of sealing systems.

New universal compound combines excellent compression set and improved resistance against autoxidation

The peroxide-crosslinked plasticizer-free EPDM compound EJ820 was specifically developed for use in drinking water applications. The material conforms to all standard national and international drinking water approvals such as KTW, W270, W534, EN681-1 including the supplementary requirement, W534, NSF61, KIWA, WRAS, ACS. The material’s low compression set guarantees long life and thus permanent and reliable sealing of all fittings, valves and pipe systems. In addition, EJ820 exhibits enhanced resistance against autoxidation.

Parker materials cover a broad range of drinking and service water applications

  • Seals for solar thermal energy systems
  • Bathroom taps and shower heads
  • Press fittings
  • Heater valves and valve blocks
  • Drinking water applications
  • Heater pumps

Below are Parker material compounds and associated specifications:

picture of parker compounds

picture of regulations for drinking water


For more information about Parker products that are applicable for drinking water and service water systems, contact Gallagher’s engineering department.

Form-In-Place Gaskets: What They Are and What They Are Not

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Ben Nudelman, Market Development Engineer, Chomerics Division.


Form-in-place EMI gaskets, also known as FIP EMI gaskets, is a robotically dispensed electromagnetic interference (EMI) shielding solution that is ideal for modern densely populated electronics packaging.

picture of CHOFORMThe most important distinction of form-in-place EMI gaskets is that they were developed for applications where inter-compartmental isolation is required to separate signal processing and/or signal generating functions.

Simply put, form-in-place gaskets are meant to reduce “noise” between cavities on a printed circuit board (PCB) or in an electronics enclosure.

In addition, form-in-place gaskets provide excellent electrical contact to mating conductive surfaces, including printed circuit board traces for cavity-to-cavity isolation. Parker Chomerics form-in-place gasket materials are known as CHOFORM.

7 reasons why form-in-place EMI gaskets can be an ideal choice

  1. Small form factor – form-in-place gaskets can be dispensed in smaller bead sizes than most traditional EMI shielding gasket solutions, 0.018” tall by 0.022” wide.
  2. Excellent adhesion – 4-12 N/cm adhesion on prepared surfaces such as machined metals, cast housings, and electrically conductive plastics.
  3. High shielding effectiveness – Parker Chomerics CHOFORM materials can provide more than 100 dB shielding effectiveness in the 200 MHz to 12 GHz frequency range.
  4. Quick programming – Because form-in-place EMI gaskets are robotically dispensed, a standard CAD file can be used to program the dispensing system and quickly map out the dispensing pattern.
  5. Complex geometries – The positional tolerance of the gasket can be held to within 0.001” and is able to follow very complex geometries including sharp turns, corners, and serpentine patterns. Other gaskets such as die cut sheets or o-rings manufacture and/or fabricate into such shapes and patterns.
  6. “T” joints – Traditional extruded gaskets are difficult to mate at intersections or “T” joints. The robot dispensing systems produce reliable junctions between bead paths to provide continuous EMI/EMC shielding and environmental sealing.
  7. Integrated solutions – CHOFORM technology combined with a Parker Chomerics supplied metal or conductive plastic housing provides an integrated solution ready for the customers’ highest level of assembly. This approach requires no additional assembly or process steps for the installation of gaskets and/or board-level auxiliary components.

Picture of Form-In-Place EMI Shielding Gaskets

Form-in-place EMI gasket limitations

  1. Large form factor enclosure sealing that can accommodate a groove. For larger areas such as machined covers that can accommodate a gasket groove, other EMI shielding solutions are better suited. In most applications, conductive elastomers such as the CHO-SEAL product line by Parker Chomerics will provide better shielding and sealing. Form in place gaskets can be dispensed in bead sizes only as large as about 0.062” tall x 0.075” wide.
  2. Enclosures requiring submersion or durable weather sealing. Because of the small form factor, FIP gaskets will not meet stringent environmental sealing requirements such as IP 67 or higher. While silicone-based, the material is better at preventing dust and environmental moisture from entering an enclosure. FIP gaskets can be paired with additional sealing gaskets for enhanced weatherproofing.

Gallagher Fluid Seals is an authorized distributor for Parker. For more information about their products, including o-rings or their various compounds, contact Gallagher Fluid Seals today.

Is an ASTM Callout the Best Way to Specify Your Elastomer Needs?

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Fred Fisher, Technical Sales Manager for Parker O-Ring & Engineered Seals Division.


ASTM Elastomer Compounds

elastomer materials pictureWhen looking at drawings to define a specific application or elastomer requirement: Is there value in using an ASTM elastomer compound description versus listing an approved Parker compound number?

Specifying a compound using the ASTM callout is a good start – it clearly defines what is wanted and it sets a minimum benchmark, which makes it easy for competitive vendors to understand what the need is. The ASTM standards also set specific test parameters which makes it much more simple to do an “apples to apples” comparison between two compounds. However, over time, here is what customers have learned:

Know Your Operating Requirements

1. The ASTM standards are very general; so when a customer defines a specific FKM they need using an ASTM callout, they might receive a compliant material that just barely meets the ASTM specifications, but did not meet the actual operating requirements. Because of that, a supplier may provide a customer with the lowest cost material. Let’s say the quality of the material is on the lower-end, but it meets the ASTM criteria requested. Because of that, the customer could see a 15% increase in assemblies requiring rework, plus a rising number of warranty claims due to seal failures. The twenty cents per seal that the customer saved for their $50 application would be offset by the cost of the increased product failures. And ultimately, this would result in an unhappy customer.

Know the Fluids Your Seals Will be Exposed to

fluid exposure2.  The ASTM standard does not specifically list what actual chemicals the seal has to be compatible with as well as the operating conditions. ASTM tests compatibility based on Standardized Testing Fluids, which are: Oils, Fuels, and Service Liquids. ASTM uses standard oils, which are defined by IRM 901 and 903. Again, the ASTM standards are excellent for comparing compounds, but most people do not have their seals operating in the ASTM reference oils and many sealing applications are exposed to multiple fluids.

Know What Your ASTM is Calling Out

3.  Most engineers or folks in purchasing who review or utilize older drawings have no idea why the original engineer chose the specific compound or why they used an ASTM callout.

So what is the best way to define and specify an elastomer? Most companies go through a technical process to specify, test. and confirm that an elastomer is the correct choice for their application. All elastomers tested and approved for the application should be clearly listed on the drawing. In addition, the drawing should clearly state that  the approved materials listed were tested to confirm their suitability for the application. All substitutes or new elastomers must be tested and approved by engineering prior to use.


Gallagher Fluid Seals is an authorized distributor for Parker. For more information about their products, including o-rings or their various compounds, contact Gallagher Fluid Seals today.

Semiconductor Fabs Lower Cost of Ownership with HiFluor Materials

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Nathaniel Reis, Applications Engineer for Parker O-Ring & Engineered Seals Division.


parker hifluor processIn our semiconductor entry from last month, we noted that lowering the cost of ownership is a multi-faceted goal. We discussed how one of the areas for potential improvement is mechanical design and how the Parker EZ-Lok seal is a major solution to mechanical seal failure. In this entry, we’ll investigate a notably different type of cost-reduction opportunity – material selection – and see how Parker’s innovative HiFluor compounds can reduce seal costs to as little as half.

Critical Environments

When it comes to the seal industry, the semiconductor market is well known as one where the most premium, chemical-resistant compounds are a necessity. Microelectronic manufacturing processes involve chemistries that push the limits of what elastomeric compounds can withstand in terms of both chemical aggressiveness and variety. The perfluorinated materials (FFKM) capable of withstanding these environments require intricate manufacturing processes regulated by closely-guarded trade secrets and the significant investment of resources.

These factors drive the price of FFKM compounds to the point of being as much as 50 times the cost of any other variety. Cutting just a slice out of this cost can result in significant savings – a chance to take out a quarter or even half the pie would be advantageous to the overall bottom line. Fabricators should be continually on the lookout for more cost-effective compounds that show equal performance in their pertinent operations.

hifluor compound pictureThis is why Parker’s HiFluor compounds offer an opportunity for cost savings that shouldn’t go unnoticed. A unique hybrid of performance between FFKM and the simpler technology of fluorocarbon (FKM) elastomers, HiFluor offers the most superb chemical compatibility in the many semiconductor environments where the high temperature ratings of FFKM aren’t necessary – and at a fraction of the cost.

Not only can HiFluor be used where even FKM is lacking, but its performance in applications with aggressive plasma exposure is spectacular as well. This can be observed by its overall resistance to plasma-induced material degradation. However, Parker has also developed multiple formulations that display extremely low particle generation when most materials would be expected to suffer severe physical and chemical etch.

Solutions and Cost Savings

As an example: One major semiconductor fab had several factors (other than their seals) dictating the frequency of their preventative maintenance (PM) intervals. The fab wanted to replace their seals at these intervals as a precautionary measure to limit the chance of them becoming another PM-increasing factor. However, this caused these premium FFKM seals to be a source of inflated cost. Parker assisted with a process evaluation that resulted in over half the seals being replaced with cost-effective HiFluor O-rings, while the tool regions with more intense plasma exposure were reserved for the elite performance of Parker’s FF302.

Another major fab in the microelectronics industry switched from FKM to FFKM seals in their oxide etch process. The tool owner achieved the desired performance improvement, but soon began searching for less expensive options. The owner recognized the plasma resistance and low particulate generation of Parker’s HiFluor compound, HF355. After implementing this change, he retained the performance improvement, but at a fraction of the cost.

Semiconductor tool owners understand that their aggressive processes require the most robust, expensive FFKM seal materials. The price tag on these seals is greater than those from any other compound family. Fortunately, HiFluor is a proven sealing solution that can bridge the gap and provide the same kind of high performance at a much lower cost.


For more information about Parker O-Rings, including HiFluor, or to find a custom solutions for your application, contact Gallagher Fluid Seals today.

What does a good seal engineering drawing look like?

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Fred Fisher, technical sales engineer of the Engineered Materials Group.


seal drawingYou just spent 6 months testing, stretching, aging and exposing your new seal design to 12 different chemicals. Finally, you are done. So what does a good technical drawing for a seal include? For most companies, the drawing is simple. For an O-ring, we draw a generic circle and show an ID and width with some sort of material call out.

But now fast forward 20 years. Someone consults the drawing – how do they know the criteria you used to select the seal specified?

Just last week I asked my customer, who was having seal failure, about the issues on their engine sensor: “Was the original seal specified to be compatible with biodiesel?” The engineer consulted their drawing, but besides the generic circle, it lacked any background on what material compatibility was considered when the seal material was selected. The ASTM description on the drawing did not include a reference to or indicate compatibility with biodiesel.

Be specific with materials

Over time, the operating parameters of a system or product can change, so it is important to know what parameters were used for the original seal selection. The goal of the drawing is to assure that the engineers and procurement team understand what performance is required from the seal and why the specific elastomer was chosen.

So how do you make your drawing more valuable to your company?

  1. Define and list on your drawing all the operating conditions you anticipate the seal will see, such as temperature, pressure, and any other application specific operating conditions.
  2. Prepare a list of fluids as well as the concentrations of each fluid that your seal will be exposed to. Add these on your drawing. In addition, make sure you consider fluids that could come into contact with the seal indirectly through failure of other systems that are part of the product or even by cleaning the product.
  3. List the selected compound and manufacturer on the drawing. Clearly define what testing the compound was put through or what testing is required for approval.
  4. If you select a compound that was resistant to compression set, high temperatures or low temperatures, as well as explosive decompression, this should be clearly stated on the drawing.
  5. List clearly the industry standards the seal is required to meet, such as UL, FDA or NSF.

List fluid compatibility requirements

fluid compatabilityTime and time again, I see seal quality and performance failures when a new supplier is selected and the real requirements for the seal were either forgotten or not clearly defined. Clearly defining these parameters and making them transparent will allow your purchasing and technical team to understand, select, and evaluate the correct compound that meets your products sealing requirements.

Once you select a compound for your specific application, it is important to test and validate that the compound chosen is compatible with the fluids you are using. Parker can typically supply small compound samples for soak testing in the fluids your seal is exposed to. If you choose to list an alternate compound on your drawing, that compound must also be tested and validated for compatibility.

Remember when developing drawings standards, assure yourself that if someone consults a drawing that is 2 years old, 5 years old or even 20 years old, they will know the intent of the original seal design.


For more information about custom sealing solutions or information about Parker seals, please contact Gallagher’s engineering department.

Semiconductor Fab Processes Benefit From Retention Ribbed EZ-Lok Seals

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Nathaniel Reis, applications engineer, Parker O-Ring & Engineered Seals Division.


When it comes to semiconductor fabrication processes, reducing the cost of ownership is a multi-faceted goal approached from a variety of angles. Tool engineers and equipment technicians take pride in their ability to identify factors that limit tool uptime. One constant headache they face is the mechanical failure of seals in dynamic environments. This can lead to premature downtime or reduced preventative maintenance (PM) intervals, both of which lead to a higher cost of ownership. Fortunately, tool owners have begun to implement seal designs better suited for these dynamic environments: Parker EZ-Lok is a proven solution.

Spiral Failure

picture of spiral o-ring failure

One of the more extreme forms of mechanical failure to be prevented is twisting and spiraling of an O-ring during operation. This occurs with O-rings in dovetail glands where one of the sealing surfaces is a door that opens and closes against the seal. The combination of stiction to the door and stretch in the gland causes the O-ring to roll and twist repeatedly with each cycle, resulting in permanent cyclic deformation. This means that a seal profile with a flat contact surface is vital for this type of dynamic function.

Other designs

The basic D-profile is the fundamental simple shape that serves as the basis of the EZ-Lok solution. The flat portion of the “D” holds the seal in place and prevents rolling, while the opposite, round contact surface focuses the sealing force and helps keep volume requirements at a minimum. These geometric features make for sound sealing function while preventing the drastic spiral damage seen so often in the industry.

picture of d-profile

A standard D-ring is still more limited by volume requirements than traditional seals like O-rings. In addition, a D-ring’s sharp corners can become difficult to install past the top groove radii if the seal is made much wider than the groove opening. On the other hand, a seal made any narrower would be easily removed without intention, such as that induced by stiction to the door. These reasons are why the basic D-profile alone is not the answer to these failure modes.

The Solution

picture of Parker EZ-Lok seal

The solution to these dilemmas is a unique D-shaped profile with a geometry that lends itself to the spacial constrictions of dovetail glands, prevents rolling, and locks into place: the Parker EZ-Lok seal. These seals are designed with special retention ribs placed with precise frequency around the seal circumference that allows for smooth installation and keeps the seal retained in the gland. This design also removes any tendency to stretch the seal during installation, which is often seen with more conventional seals.

The combination of retention ribs with a fundamental D-ring profile makes EZ-Lok the ideal geometry for effective use of the high-performance compounds typically required for aggressive semiconductor chemistries. EZ-Lok seals allow for lower cost of ownership through PM-minimization and reduced seal overhead costs, made possible by effective mechanical design. This is an example of how Parker’s effective design engineering can reduce the cost of ownership and bring premier solutions to the table.


For more information about Parker’s full suite of solutions and sealing products, contact Gallagher Fluid Seals’ engineering department.

Why is Outgassing Critical in Optics and Electronics Applications?

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Dorothy Kern, applications engineering manager, Parker O-Ring & Engineered Seals Division.


electronic boardFor some applications, a critical component of selecting a seal material is a phenomenon known as “outgassing”. However, even within the elastomer community, outgassing is not something that is commonly considered. Which begs the questions: what is outgassing and why is it important?

Outgassing is usually most relevant in vacuum applications, where the vacuum causes the elastomer to release constituent material. The constituent material could include water vapor, plasticizers, oils, byproducts of the cure reaction, or other additives used in the seal material. Outgassing becomes a problem if a thin film of those chemicals condenses and is deposited on nearby surfaces. Such a film poses major challenges in highly sensitive applications, such as optics or electronics, where cleanliness is of utmost importance. A seal material with low outgassing  is essential because it shows the seal material does not emit volatile constituents under vacuum conditions.

Weight loss of compounds in vacuum

Outgassing is most often characterized by weight loss of the seal material. The ASTM test method E595 is one way to quantify outgassing by measuring Total Mass Loss (TML %), Collected Volatile Condensable Materials (CVCM %) and a reported value for Water Vapor Regain (WVR %).  Measurements are taken following a 24 hour exposure to vacuum of 5×10-5 torr at a temperature of 257°F.

Taken together, these three parameters tell a complete story. The TML is reported as the percent of the specimen’s initial weight that is lost during the test; under standard criteria, the result must be less than 1.00% mass loss. Obviously, minimizing TML is a good thing, but it is not the only important factor. Collected volatile condensable material (CVCM) is the amount of outgassed matter from a specimen that condenses onto a collector during the maintained time and temperature. CVCM is of particular concern because any material that readily condenses in the test is likely to condense on and contaminate nearby surfaces during use. To pass the standard CVCM requirement, the amount collected relative to the initial mass of the specimen must be less than 0.10%. The final measurement, WVR, is the mass of the water vapor absorbed by the specimen after a 24-hour stabilization at 23°C in a 50% relative humidity atmosphere. There is seldom a pass/fail limit for WVR; instead this result is merely reported. In many applications, the small amount of water vapor lost by a seal may not be of concern, particularly if the application already includes a means of controlling moisture. Further, any WVR is presumed to be equal to the portion of original TML that was water vapor. The difference between TML and WVR is therefore presumed to be volatile organic material that has evaporated out of the material (only some of which condenses in the CVCM test), so minimizing the difference between TML and WVR is also of considerable importance.

To illustrate, we can look at the most recent outgassing data completed on a few popular low temperature fluorocarbon materials. Table 1 contains the results from a 3rd party laboratory to measure the outgassing properties of VM125-75 and VX065-75. Both had undetectable amounts of CVCM and very small differences between TML and WVR.  VX065-75 in particular displayed remarkably little outgassing as well as a low WVR.

There are a few additional resources detailing seal materials that are known for having low weight loss. The O-Ring Handbook ORD 5700, Table 3-19 (page 65 of the pdf), has a few legacy materials with weight loss percent after a two-week exposure to 1 x 10-6 torr vacuum level, at room temperature. Additionally, non-Parker resources such as the NASA website contain an interesting summary of a much broader range of materials.


For more information about outgassing or electronics applications, contact the Gallagher Fluid Seals engineering department.

Degradable Materials Simplify Well Completions in Oil & Gas Extraction

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by members of the O-Ring & Engineered Seals Division. Jacob Ballard – research and development engineer, Jason Fairbanks – market manager, and Nathaniel Sowder – business development engineer.


degradable materials for offshore drillingThe emergence of degradable and dissolvable materials is providing oilfield service companies an opportunity to increase efficiencies and cut costs in the oilfield by simplifying well completions. These materials replace their conventional metallic and polymeric counterparts in completion tools, but eventually break down and disperse when exposed to common completion fluids. This eliminates the need for well interventions to mill out or retrieve used tools. This can result in a reduction of drill time, a safer work environment, and monetary savings for the operator. Parker Hannifin produces dissolvable and degradable metal alloys, thermoplastics, and elastomeric materials that can enhance your well completions.

Degradable Elastomers

Parker O-Ring and Engineered Seals (OES) Division produces degradable elastomer formulations that can be used in frac plugs, liner wipers, and other sealing applications common in the completions segment. These elastomer formulas have tough physical properties and low compression set and are designed to replace materials such as Nitrile or HNBR in conventional tool designs. With proper design, tools using Parker degradable elastomer can withstand the high pressures (>8,000 psi) generated during hydraulic fracturing while still eventually deteriorating away, allowing well production without having to be drilled out. These degradable elastomers can be produced in a variety of desired forms such as O-rings, custom molded shapes, and packing elements. They can also be bonded to dissolvable metal alloys to produce completely degradable solutions. If needed, Parker offers a product engineering team to assist with the design of components and rapid prototyping services to help cut down on development timelines.

Degradable Thermoplastics

Parker Engineered Polymer Systems (EPS) Division manufactures engineered degradable Thermoplastic materials which can be used in many types of completion tools that traditionally use non-degradable elastomers. Parker EPS’s high-grade thermoplastic materials have increased physical properties over conventional elastomers making it ideal for both high pressure/high temperature and wear resistant applications. The increased physical properties of EPS thermoplastics provide enhanced resistance to extrusion, temperature and wear over most degradable non-metallics in the market. These unique thermoplastic materials may be manufactured in both homogenous as well as bonded components such as Packers, Parker back-up rings, Frac Plugs and liner wipers and are ideal for hot trouble well applications.

With a wide range of wellbore temperatures and completion fluids seen across the industry, selecting the right degradable compound can be complicated. Gallagher Fluid Seals, in coordination with Parker, can help assist in recommending the proper paramaters for using degradable elastomers.


Gallagher Fluid Seals is an authorized distributor of Parker. To learn more about how Gallagher Fluid Seals can help you, contact our engineering department at 1-800-822-4063

Parker’s EM163-80 Meets Both NAS1613 Revision 2 and 6, Is There a Difference?

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Dorothy Kern, applications engineering manager for the Parker O-Ring & Engineered Seals Division.


Perhaps you know Parker’s newest EPDM material is EM163-80. Featuring breakthrough low temperature functionality, resistance to all commercially available phosphate ester fluids, and the ability to be made into custom shapes, extrusions, and spliced geometries, EM163-80 represents the best-in-class material for applications needing to seal phosphate-ester-based fluids. The latest news is that EM163-80 meets the full qualification requirements of both NAS1613 Revision 6 (code A) and the legacy Revision 2 (no code). Parker has been inundated with questions about the specification differences between Revision 6 and 2, enough that it makes sense to devote a blog topic explaining the fluids, conditions, and dynamic cycling requirements which are required to qualify EM163-80 to each specification.

The easiest part of this comparison is evaluating the areas of Revision 6 which are very much a copy and paste from Revision 2. Compression set conditions, aged and un-aged, plus temperature retraction requirements, aged and un-aged, are identical. Lastly, both specifications require a test to verify the elastomers will not corrode or adhere to five different metal substrate materials. That is pretty much where the similarities end.  Now for the contrasts.

Specimen size

The first subtle difference is the specimen size. Both specs require testing to measure the change in physical properties and volume following a heated immersion in phosphate ester fluids. For the most part, No Code qualification requires testing to be completed on test slabs or O-rings, while the newer revision, Code A, requires testing on test slabs AND O-rings. Not a big difference, but still, a difference.

The fluid conditions are very similar in both specs, but not identical. There are only two temperatures for the short term 70 hour exposure: 160°F and 250°F. Another similarity is that the longer soaks are at 225°F for 334 and 670 hours. The more difficult A Code also requires 1000 and 1440 hours at 225°F. We begin to see the requirements for the later revision are more reflective of the industry conditions, right?

Fluids

Next, we look at the fluids, which truly are a key difference between the two documents. Revision 2 fluid is exclusively for AS1241 Type IV, CL 2 while revision 6 states the elastomers must meet “all commercially available AS1241 Type IV, Class 1 and 2, and Type V”. Table 1 outlines the AS1241 fluids in context of both NAS 1613 revisions.

Revision 2 Revision 6
Low Density Hyject IV A Plus AS 1241 Type IV class 1 X
Low Density Skydrol LD4 AS 1241 Type IV class 1 X
High Density Skydrol 500B-4 AS 1241 Type IV class 2 X X
Low Density Skydrol V AS 1241 Type V X
Low Density Hyjet V AS 1241 Type V X
Low Density Skydrol PE-5 AS 1241 Type V X

Basically, to pass Revision 6, the material must demonstrate compatibility for all six commercially available fluids, while Revision 2 only has one fluid which is must be verified for compatibility. Again, we see Revision 6 is much more comprehensive than Revision 2.

Endurance Testing

picture of o-ringsLast, we look at the functional testing of the materials, referred to as dynamic or endurance testing. Both specifications require endurance testing on a pair of seals, which have been aged for a week at 225°F. The appropriate fluids are outlined in the table above.

Revision 2 has a gland design per Mil-G-5514. There is a 4” stroke length and the rod must travel 30 full cycles each minute. The rod is chromium plated with a surface finish between 16-32 microinches. PTFE anti-extrusion back up rings are necessary for the 3000 psi high pressure cycling. A temperature of 160°F is maintained for 70,000 strokes and then increased to 225°F for an additional 90,000 strokes.

Revision 6 has a much more demanding endurance test with fives phases and slightly different hardware. The rod must be a smooth 8 to 16 microinches Ra with a cross-hatched finish by lapping, and the cycle is 30 complete strokes per minute but only 3” rather than 4”, which means the speed can be more conservative. A pair of conditioned seals are placed in AS4716 grooves, adjacent to a PTFE back up ring. Similarities to Rev 2 are that there is a pressure of 3000 psi for the dynamic cycling at both 160°F and 225°F, however before and after each high temperature cycle there is a low temperature, -65°F soak. The first soak is static for 24 hours, followed by the 160°F high pressure cycling. The second low temperature soak requires 10 dynamic cycles at ambient pressure followed by 10 cycles at 3000 psi. The final low temperature soak requires one hour static sealing at 3000 psi followed by an 18 hour warm down period.

If you read carefully through the tests, you begin to see the Revision 6 seals must go through a more rigorous test with harsh low temperature, low pressure conditions. However, Revision 2 is not without its own challenges. The required hardware configuration; ie, low squeeze and more rough surface finish, is far from optimum and not what we recommend in actual service conditions. Added to the difficulty is the longer stroke length and faster speed. The fact that EM163-80 has passed both specifications proves it is the next generation EPDM seal material ready for flight.


Gallagher Fluid Seals is an authorized distributor of Parker. To learn more about how Gallagher Fluid Seals can help you, contact our engineering department at 1-800-822-4063

Reduce Maintenance Costs When Sealing Dry Running Equipment

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Nathan Wells, Application Engineer, Parker Engineered Polymer Systems Division.


My grandpa used to have a rusty, old air compressor in his shop. As a child, when my siblings and I would visit him, he’d use it to power air wrenches, grinders, and inflate flat soccer balls for us. I noticed it had a port labeled “ADD OIL DAILY” that was covered in the same thick layer of greasy dust as all the other unused junk in his shop. Knowing my grandpa, if asked about adding oil he probably would have said, “Oil is expensive. That’s how the companies get ya!” The compressor’s seals leaked so badly, you could hear the hissing even over the loud motor. I was certain one day it would explode.

picture of dry running equipmentPneumatic tools are common in factories, tool shops, and DIY garages around the world. Using compressed air for power is convenient, simple, and — when maintained properly — safe and efficient. However, air treatment costs can add up fast. Traditional rubber seals used in air tools require clean, low moisture, compressed air with the proper amount of lubrication added. Good Filter/Regulator/Lubricator systems (FRLs) cost as much as the tools themselves! So, what would happen if we didn’t have to provide pristine air?

Today we have the technology to create seals for tools which don’t require daily or even yearly upkeep. You’ll find these tools labeled “maintenance-free,” which sounds great to the guy responsible for maintenance. It sounds even better to the guy paying for maintenance … and to engineers designing tools who want to keep warranty costs down.

Seal materials for dry running

Early pressure seals were made out of leather. My grandpa’s compressor probably wasn’t that old, but even since his time, we’ve come a long way.

When I’m asked for seal recommendations in totally dry-running applications, my mind clicks to a material called PTFE (chemical name polytretrafluoroethylene). Most people know PTFE by the brand name Teflon® and are familiar with its use when applied to cookware as a high temperature, slippery, non-stick coating.

PTFE is a semi-hard plastic which feels slick to the touch thanks to its low friction properties. It’s considered self-lubricating because it leaves micro deposits on the sealing surface and reduces friction after just a few strokes. Because of this, it’s good for high-speed sealing and can operate completely dry.

By adding fillers to PTFE, seal manufacturers can tailor materials for greater suitability in meeting performance requirements for a wide range of conditions. String-like additives including fiberglass and carbon fiber increase pressure rating, wear resistance and seal life. Dry lubricant-type additives such as graphite or molybdenum disulfide (MoS2) further increase a seal’s ability to run without lubrication, and at higher speeds and pressures. In pneumatic medical, pharmaceutical, and food processing systems, clean grade mineral-based strengtheners may be used as additives.

PTFE seals for dry running equipment are available in several profile configurations:

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