The zenith of rubber material technology is in perfluoroelastomer compounds, also known as FFKM. Sometimes considered the rubber version of PTFE, a perfluoroelastomer contains a fully fluorinated polymer back-bone and a proprietary cure system. These traits allow FFKM to achieve outstanding chemical resistance and excellent heat stability, perfect for Oil & Gas, Aerospace, Chemical Processing, and Heavy Duty Truck applications.

The nature of FFKM material also allows for extremely clean manufacturing, making many compounds highly suitable for use in the cleanest environments of semiconductor and pharmaceutical processing. Parker ULTRA compounds are perfluoroelastomer materials tailored for specific applications to make the best use of FFKM’s excellent traits. Some of the most unique and exceptional Parker ULTRA materials are discussed below.

Choosing the right seal for aggressive chemical media like steam and amines can be a difficult process. These chemistries can cause degradation in most elastomers, causing seal failure. Luckily, Parker ULTRA compounds FF580 and FF582 compounds offer best in class chemical resistance allowing for continuous operation in the toughest media. These are 75 and 90 durometer formulations which have excellent compatibility with a variety of media including best in class base and steam resistance along with many other aggressive media types. Both compounds have outstanding compression set resistance and a maximum operating temperature of 275°C. 

When the toughest system condition is high operating temperature and long life is desired, Parker ULTRA FF200 is recommended. Outstanding heat resistance and impressive compression set resistance allows the FF200 to seal continuously at temperatures of 320°C. As a standard FFKM, FF200 also offers good chemical resistance to organic and inorganic acids, ketones, and a variety of other media. The FF200 material is also on the qualified products list for AMS 7257 making it the ideal choice for many Aerospace engine applications. 

Traditional FFKM materials have always offered great chemical and heat resistance but have typically lacked low temperature capabilities. The standard FFKM lower operating limit is -15°C. One of the most impressive Parker ULTRA compounds is the FF400, which offers unparalleled low temperature service compared to standard perfluoroelastomer materials. With the FF400 compound, temperatures as low as -40°C can be achieved, making this the ULTRA compound of choice when chemical resistance and high temperature service is needed in combination with low operating temperatures. 

Semiconductor applications can be challenging systems for elastomers due to the high degree of cleanliness required in addition to the very aggressive chemistries necessary to process silicon wafers. These traits have historically been at odds; extremely clean materials tend to erode rapidly in aggressive plasma chemistries while plasma resistant elastomers tend to run the risk of higher process contamination due to metallic content. Parker has pushed the limits on compounding technology to develop ULTRA FF302, offering excellent etch resistance in oxygen and fluorine plasmas while maintaining extremely low metals content. The FF302 provides robust sealing against CF4, NF3, O2, and O3 plasmas and has a continuous operating temperature of 315°C. The low metallic ion content and best in class extractables ensure that the FF302 will not contaminate sensitive processes. For more information on the FF302 compound, please click here for the bulletin. 

Extreme environments require the most advanced sealing technology available. Whether it is high or low temperature, aggressive media, or a high degree of cleanliness, Parker ULTRA compounds offer a solution for each. Parker’s rubber chemists are continually working on new developments to help push the boundaries of what is capable in elastomeric technology. Another benefit to Parker ULTRA materials is their availability. Parts can be produced quickly to help meet production needs. Due to the unique nature of perfluoroelastomer materials, standard gland design is typically not well suited for extreme conditions. Parker Application Engineers can help with seal design to ensure good design practices are put in place. For particularly challenging applications and for more direction on choosing a sealing material, please contact a Parker Applications Engineer via online chat or email, or by calling 859-335-5101.

This article was contributed by Eric Uehlein, Applications Engineer, Parker Hannifin O-Ring Division.

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Operators of fluid power systems increasingly demand friction-optimised piston and rod seals for hydraulic cylinders. High friction not only means high use of energy, but can also lead to premature seal failure due to wear.  Both of these aspects are costly as well as harmful to the environment.

The HL rod seal by Parker Prädifa is a friction-optimised sealing solution featuring an effective functional principle: the single-acting seal has pressure-activated, cascading dynamic sealing edges. This design clearly reduces static and dynamic friction in hydraulic cylinders and increases the efficiency of hydraulic systems. The P6030 polyurethane material superbly supports the profile geometry
and its action principle. P6030’s main advantages are excellent temperature,
extrusion and wear resistance. 

Various parameters influence friction of hydraulic seals. The size of the contact area between the seal and the respective sliding partner is one of the key factors: the larger the contact area of the seal, the higher the amount of static and dynamic friction. The system pressure inside a hydraulic system determines the friction properties required of the seal. For example, friction at lower system pressures or in differential cylinders with low pressure differences is significantly more critical than in cylinders subjected to higher pressure loads. 

When conventional U-rings are used, a larger portion of the dynamic sealing area will typically contact the piston rod surface even at lower system pressures. By contrast, in the case of the HL rod seal, the sealing edges of the dynamic sealing lips will successively contact the mating surface as system pressure rises. This significantly reduces friction in the pressure-less state and in low-pressure conditions. The small contact area reduces the generation of heat and friction as well, thus enabling higher travel speeds.

Depending on the system pressure applied, the individual sealing lips are activated by the deformation of the seal’s cross-section. This in turn reduces the amount of drag oil on the rod surface that occurs during the cylinder stroke, and thus increases the sealing effect. Additionally, in case of slow travel speeds, the risk of stick-slip is nearly excluded.

Hence the sealing performance increases with the number of sealing edges and their effects. At the same time, dynamic friction slightly increases as the contact area enlarges. Overall, however, it remains at a very low level.
Since only the primary sealing edge is engaged in pressure-less conditions the new functional principle minimises the high break-away friction typically occurring after prolonged downtime. This phenomenon is also known as the “Monday morning effect”.

The new HL rod seal can be used as both a single seal with a wiper and as a secondary seal in a sealing system behind a primary or buffer seal.

•          Extremely low friction
•          No stick-slip, even in case of low travel speeds
•          Optimum sealing function
•          High wear resistance
•          High extrusion resistance
•          High temperature resistance
•          Easy fitting
•          Short fitting space
•          Also ideally suited for use as a secondary seal in a sealing system

Brochure HL Rod Seal Low friction - pressure controlled

HL Rod Seal Product Detail Page

More details on our Prädifa Technology Division

Article contributed by

Christine Stehmans
Marketing Communications Manager,
Engineered Materials Group Europe
 

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O-rings are the simplest, most readily available type of seal used across every industry and market. They are arguably the best seal for many applications, but perhaps daunting to an engineer with no experience in seal design. The O-Ring Basics chapter of Parker's eHandbook provides an overview of what an O-ring is, how it works, and finally, the benefits over other seals.

One very important consideration is the hardness of a rubber material. A customer may need to seal a high pressure fluid, which would call for a harder material. On the other hand, he might want to minimize insertion force, or the O-ring may be sealing some delicate hardware, such as thin plastic or a sapphire plate. This may call for a softer material. For testing the hardness of the material, Parker recommends Shore A hardness. It is an industry standard test for rubber, and it is an acceptance criteria for every batch of O-ring material mixed by Parker.

Shore A hardness testing is performed using a durometer, which was developed by Albert Ferdinand Shore in the 1920’s. The Shore A hardness measurement is often colloquially called “durometer” or “duro”. This test is performed on cured rubber sheets per ASTM D2240, and on finished O-rings per ASTM D1414. 

The device consists of a hardened steel rod with a truncated cone at the tip. The steel rod is spring-loaded and actuates a dial with a scale of 0 to 100. The test specimen is placed directly underneath the truncated cone, and the device is pressed down onto the part until the flat metal plate on the bottom is flush with the rubber specimen.

The more the cone deforms the rubber material, the lower the hardness measurement. The less the cone deforms the rubber material, the higher the hardness measurement.

Parker compounds utilize a distinct numbering system, which consists of one or two letters to designate material, a three or four digit identification number, and a two digit number for the Shore A hardness. Two examples of this are N0674-70 and NM304-75. Of particular interest are the last two digits, which indicate the nominal hardness of the material. Compound N0674-70 has a Shore A hardness of 70, while NM304-75 has a Shore A hardness of 75. The tolerance on the Shore A hardness is +/-5 for all Parker compounds.

For further information, check out the Material Selection Guide which provides a compound family overview including a description of compound advantages, typical temperature maximum/minimum, compatible fluids, and material durometers. A list of incompatible fluids are also detailed, allowing the user to receive a concise summary of the most common, and even the more obscure elastomer types. And check out the Parker O-Ring eHandbook or visit the Parker O-Ring Division for further information and useful tips on how to select an O-Ring. If you have any questions, please feel free to contact Parker applications engineering at 859-335-5125. 

This article was contributed by

David Mahlbacher, Parker O-Ring Division, Applications Engineer

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With the price of oil at rock bottom, it seems that no one is interested in biodiesel these days. But don’t think that cheap oil is a long-term solution. At some point, the price of oil will rise and biodiesel will once again be making the news.

Diesel engine fuel systems use fluorocarbon elastomers almost exclusively. Most systems use the traditional Type 1, or copolymer, grade of fluorocarbon like Parker compound VM100-75. It’s the most cost effective of all the fluorocarbons, has excellent compression set resistance, and does a wonderful job with diesel fuel. It’s not as good for low temperature as the low temperature (Type 3) fluorocarbon materials, but diesel fuel and biodiesel both gel at low temperatures, so this limitation doesn’t pose a real-world leakage risk.

Through extensive testing, we’ve found that the “old standby” fluorocarbon compounds do a decent job in the common 20% biodiesel blends (B20) as long as the application temperature stays below 100°C.

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Of course, these are not the only possible options for use in biodiesel. Other materials may be considered, but they were not evaluated in this particular study.

O-rings can typically seal to about 8°C below their TR-10 value in static applications and down to their TR-10 value in dynamic applications. The goal in the diesel engine industry is to seal at -40°C without leakage. To date, that has not been an issue for Type 1 FKMs in diesel and biodiesel applications.

In this case, the best materials for biodiesel in this testing, Parker compounds VG286-80 and V1289-75, also offer improved low temperature performance.

Type 1 fluorocarbon compounds like VM100-75 will continue to be the low cost solution for sealing diesel and biodiesel. In fact, these materials have been used successfully in ongoing multi-year customer field trials without fuel leakage. However, Parker’s low temperature (Type 3) fluorocarbon compounds VG286-80 and V1289-75 offer significant improvements in compatibility with wet and contaminated biodiesel, as well as an additional safety factor for low temperature function.

For more information visit the Parker O-Ring Division and speak online with our experienced applications engineers.

This article contributed by Dan Ewing, Senior Chemical Engineer, Parker Hannifin O-Ring Division.

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Most pharmaceutical manufacturers produce drugs in large vats of living cell cultures. For the production of these drugs, it is extremely important to ensure that these cell cultures are not exposed to any cytotoxic contaminants that may leach out of the seals. It is also imperative that cytotoxic contaminants not be present in the finished drug, especially for infants, and for patients who are pregnant or nursing.

Before an O-ring is approved for the pharmaceutical industry, it needs to be tested for cytotoxicity (cell toxicity). This is usually tested in the United States per USP <87>, and internationally per ISO 10993-5. These two tests are very similar in methodology and criteria. Both cytotoxicity tests use L-929 mouse fibroblast cells, which are an industry-standard cell used for cytotoxicity testing. Cultures of these cells are produced in glass flasks prior to testing. Extracts are prepared using 3 test articles: the O-ring material, a negative control article (HDPE), and a positive control article (PVC for USP <87>, and powder-free latex gloves for ISO 10993-5). These extracts are then added to the cell cultures. Cells are incubated with the extracts and then examined after 48 hours. The grading scale is from 0 to 4, with 0 meaning cells are completely unaffected, and 4 meaning all cells are destroyed. For the test to be valid, the HDPE extract must have a grade of 0, and the PVC extract must have a grade of 3 or 4. The O-ring material meets the requirements if the biological response is less than or equal to grade 2. Materials that pass the requirements of USP <87> or ISO 10993-5 are generally considered non-toxic to cells.

Parker offers several O-ring compounds that have been tested for cytotoxicity. 

If you have any questions or would like to learn more about O-ring Cytotoxicity testing, please feel free to contact Parker applications engineering or check out our interactive O-Ring eHandbook.

This article was contributed by David Mahlbacher, applications engineer, Parker O-Ring Division

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Environmental Seal Enclosure 101

Efficiency gains in the automotive industry are not limited to engine designs. Transmissions are also undergoing significant changes to increase fuel mileage. To reduce friction and cope with more gears (or even an infinite numbers of gears with a Continuously Variable Transmission (CVT), new Ultra Low Viscosity (ULV) transmission fluids and CVT fluids have been developed. Fortunately, Parker has already performed a significant amount of testing in these new fluids.

Automotive transmission seal material usage varies widely by manufacturer and, in some cases, by seal type within a transmission. To keep the length of this blog to a readable size, I will focus on materials most commonly used in O-ring applications within automatic transmissions. Ethylene acrylic elastomer (AEM) is the most common elastomer in North America, but various fluorocarbon (FKM) elastomers are also used.

Each of these material types has its pros and cons. AEM is the most cost-effective, but this material degrades more quickly in transmission fluids. Type 1 FKM is a cost effective FKM and has good fluid resistance, but its low temperature flexibility is relatively poor. Type 3 FKMs offer the best low temperature performance and fluid resistance, but they come at a price.

In terms of compatibility, ULV fluid interactions with elastomers are similar to those of Dexron VI and Ford F-type fluids. AEM tends to swell more than the different grades of FKM. There is almost no swell of Type 1 FKM in the different fluids, but it does experience moderate-to-significant losses in tensile properties over time at 150°C. Type 3 FKM does not suffer this degradation.

*Results for V1475 listed in the table above are based on 1008 hrs. @150°C.

Parker’s Type 3 FKM compound VG286-80 has also been tested in a number of advanced CVT fluids, all with outstanding results.

O-rings can typically seal to about 8°C below their TR-10 value in static applications and down to their TR-10 value in dynamic applications. The goal in the automotive industry is to seal at -40°C without leakage. For the AEM and -30°C Type 3 FKM GLT-type compounds, that’s realistic for static applications, but if there is significant movement in the joint, some leakage may occur. Short of redesigning the application, the only solution is to use a seal material with better low temperature performance.

Based on this, ACM and Type 1 FKM O-rings should leak at -40°C. However, the fluid itself helps prevent low temperature leakage. Transmission fluids increase in viscosity at low temperatures, and at -40°C, they exhibit very little natural flow. This increase in viscosity prevents the fluid from seeping past the seals when the seals and fluid are at -40°C. In addition, transmission fluids heat up very quickly upon vehicle startup, and the fluid in turns warms the seals. In practice, these two factors are sufficient to prevent leakage.

However, this phenomenon may not occur with the newer fluids. ULV and CVT fluids tend to have much lower viscosity; this means they don’t thicken as quickly at low temperature and they don’t generate heat as quickly upon vehicle start up. For these fluids, use of improved low temperature seal materials is strongly recommended. This is where Parker compounds VG286-80 and V1289-75 come into play. These Type 3 FKMs beat all of the incumbent materials in low temperature performance by a significant margin.

AEM materials will likely continue to be the low cost solution for sealing transmission fluid. However, low temperature (Type 3) fluorocarbon materials such as VG286-80 offer significant improvements in low temperature and fluid compatibility. While they are more expensive, they offer a near-bulletproof sealing solution for containing transmission fluids.

For more information on the materials mentioned above, or to speak with an applications engineer, please visit the Parker O-Ring Division or contact us at 859-339-5650.

This article contributed by Dan Ewing, senior chemical engineer, Parker Hannifin O-Ring Division.

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Shielding for electromagnetic interference (EMI) is critical to military electronics systems operating in demanding environments requiring low emitted electronic signatures and protection from electromagnetic radiation. In mobile military applications, EMI shielding must be maintained during storage, transport and operation in a wide variety of demanding and corrosive environments.

An integral part of the EMI shielding system is an EMI shielding caulk that seals the seams on external structures from panel to panel to ensure conductivity around the entire system. The caulking maintains a faraday cage that protects the internal electronic components against external electromagnetic interference and/or electromagnetic pulses (EMP). This prevents a possible failure mode of the EMI shielding enclosure when two metal panels are joined together without protecting the seam with a reliable caulking. If there is no caulking or if an inferior caulking fails, there is a significant opportunity for EMI emissions/susceptibility. 

Parker Chomerics has developed the next generation EMI shielding caulk for use on military radar shelters. The new CHO-BOND® 1019 provides a substantial increase in performance over existing legacy materials by improving EMI shielding performance, corrosion resistance and by reducing application time. In addition, the new CHO-BOND® 1019 is paintable, eliminating the need for expensive intermediate layers. Along with better shielding performance, these features translate to significant savings by reducing manufacturing and material cost, increasing throughput, increasing the working life of the shelter and reducing maintenance costs.

To learn more about the science applied, trial formulations subjected, rigorous testing standards and results obtained, download our whitepaper: EMI Shielding Caulk Delivers Superior Performance in Military Radar Systems.

Military systems require rugged performance

EMI shielding plays a major role in military applications. The U.S. military has utilized EMI shielding caulks for decades on electronics’ housings such as radar shelters, radar test facilities, etc. A popular example, the AN/MSQ-104 Engagement Control Station (ECS), the command and control unit of the Patriot Missile firing battery, is housed in an EMI shielded radar shelter mounted onto the bed of a cargo truck or similar vehicle. Whether the ECS is being transported or operated under battle conditions, it experiences jolts and vibrations that can fatigue the rivets holding the aluminum shelter panels together; any loosening of the rivets will compromise the integrity of the EMI Shielding system around the command and control electronics inside the unit.

This would result in the system being vulnerable to EMI, thereby risking the proper operation or exposure to enemy anti-missile systems. This risk must be minimized since the U.S. Army and allied nations rely on the Patriot as their primary anti-ballistic missile system in the mission to protect strategic areas. Systems such as the AN/MSQ-104 have advanced technologically and increased in usage over the years. Furthermore, newer electronic components require even more EMI shielding levels that legacy caulks cannot attain.

Legacy EMI shielding caulks failure modes

Legacy EMI shielding caulks are single-component, non-hardening compounds made of traditional materials such as silicone filled with silver-plated copper. A key vulnerability of these materials traditionally has been corrosion issues. These legacy formulations have shielded against EMI but now fall short in applications where modernized high speed and high energy electronics are concerned. These advanced electronics are more sensitive to EMI and operate in a wider range of frequencies and, therefore, require improved shielding across the frequency range to receive proper protection. In order to provide improved shielding and corrosion resistance, it is necessary to use conductive fillers that deliver higher levels of shielding typically provided by silver-plated particles while improving upon the relatively poor corrosion resistance typically experienced with copper-based particles. Additionally, there are application issues that need to be addressed:

• compound cure time
• application temperature ranges
• ease of paintability with camouflage patterns

Often, epoxy-based paints applied to radar shelters will not adhere to silicone compounds. In this case, it is necessary to apply a polysulfide environmental sealant over the caulk to provide a paintable surface. The caulk and the polysulfide each require seven days (fourteen days total) to cure and must be applied in a temperature-regulated environment to ensure proper final-cured properties. In manufacturing, the fourteen days of waiting are logistically time-consuming and costly.  Maintaining acceptable warehouse temperatures for application is also challenging. CHO-BOND® 1019 cures quickly and requires less time in narrow temperature ranges after application. Legacy caulks regularly experience cracking and corrosion over time, which leads to costly field repairs. CHO-BOND® 1019 resists cracking and corrosion significantly over those legacy products.

Optimize your process with CHO-BOND® 1019 Caulk

The next-generation CHO-BOND® 1019 is a fast-curing, paintable caulk that provides improved shielding and corrosion properties over the traditional caulks. It also has an improved application temperature range. In this product, we combine our metallic filler technology with cutting-edge base polymers to provide a unique formulation. This new technology transcends the legacy EMI shielding caulks as well as those compounds recently developed for similar modern military applications.

Our resulting CHO-BOND® 1019 EMI shielding caulk achieves superior results including:

Substantial cost savings

• Paintability
  • No intermediate polysulfide layer = reduced labor and materials
• Faster cure
  • Increased throughput = reduced inventory costs
• Increased application temperature range
  • Decreased heating/cooling cost within manufacturing plants

Increased performance

• Improved EMI shielding performance
  • Better EMP protection
  • Ability to use a great number of more sensitive equipment
• Superior corrosion resistance
  • Increased working life of shelter
• Increased flexibility
  • Reduced vulnerability to transportation and vibration

Our R&D engineers are experts at filler-resin combinations that will deliver the performance improvements necessary for the latest technologies.

Article contributed by Nick Pascucci, product development engineer, Parker Chomerics Division. 

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The Art of Spraying Electrically Conductive Paints 

The Benefits of Thermally Conductive, Fully Cured Dispensable Gel

How to Enhance Safety and Avoid Mix-up of Seals in Automotive Applications

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Sealing and Shielding Technologies and Key Markets

In the medical industry, oftentimes it is necessary to test a single blood sample a number of times. Other times, a patient may need to be injected with multiple doses of a medicine or nutrient throughout a single day. Thinking these examples through, it would be costly and wasteful to continuously take new samples of blood or open new vials of medicine each and every time it is needed, when you could use the same one numerous times. That is where using an elastomeric self-sealing septa (also known as a resealable septa) can make medical practices run more smoothly and efficiently.

Consider the below example to better illustrate the cost effectiveness of resealable septa.

A malnourished patient at a hospital requires enteral feeding in order to obtain his/her daily nutrition. The feeding tube is connected to a bag containing liquid nutrition, which must be given to the patient every six hours. An appropriate dose of nutrition is drawn from the bag by a syringe and then delivered into the patient’s system via the feeding tube. In this example, this must be done every six hours for approximately 15 days.

Without resealable septa, the bags would not be sealed again after every puncture, thus the patient would require four separate single-dose bags per day.  This adds up quickly, totaling 60 bags of nutrient in a 15 day period that the hospital would purchase for just a single patient.

Not only does the hospital pay for the nutrient bags, it also has to pay for the nurse practitioner responsible for changing those bags. It takes the nurse approximately 30 minutes to replace the nutrient bag and clean the feeding tube, costing the nurse two hours per day and the hospital more money to pay for his/her wages.

If the bag can be resealed after each puncture, the number of nutrient bags needed per patient will be reduced. A hospital, for example, could use one bag per day instead of the four used in scenario one. Resealable septa can help the hospital cut cost of bag material by 75 percent.

In addition, the nurse’s time spent on this patient will also decrease, saving the hospital money in wages. The nurse would only have to change the feeding bag once per day instead of the original four, allowing the nurse more time to take care of other patients.

*Note that the hospital will still be purchasing the same amount of nutrient in both scenarios regardless of packaging size.

The variable cost of managing a patient with an enteral feeding tube is four times higher in scenario one than in scenario two. Using bags with resealable septa helps the hospital not only decrease the number of bags used but also consequently will save on supply cost and average time spent on each patient. In addition, fewer bags may reduce the cost of transportation, bag storage, and waste management, freeing up additional resources for other healthcare-related activities. Similar cost and waste saving benefits can also be applied to non-hospital settings, especially in a long-term care facility.

For more information about Parker’s self-sealing septa, please check out part 1 of this series “What Qualify as Self-Sealing Septa” and please direct any inquiry about this self-sealing technology to O-Ring Division.

If you would like to speak with our team directly, visit us at the MD&M West Conference and Exposition, Booth# 2413, February 7-9, 2017 at the Anaheim Convention Center, Anaheim, California.

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More often than not, an O-ring makes for a great sealing element. They seal over a wide range of pressure, temperature and tolerance. Normally they require very little room, are readily available, and easily sourced. However, there are specific applications that may be better suited for an alternate type of seal, such as a double chamfer radial seal. 

Single-use systems (SUS) for up- and downstream processing in the pharmaceutical industry have become widely accepted in recent years due to their advantages in many operations, such as vaccine production. Parker Prädifa has extended its in-house overmolding technology and offers process engineering solutions specifically focused on these systems. 

Essentially, the single-use approach aims to deliver sterile, ready-to-use systems based on plastic and rubber components directly to the user’s production environment. The systems then only have to be connected and can be disposed of after they have been utilized. This eliminates the need for complex logistics, cleaning procedures and assembly of the single components. Furthermore, this approach provides higher flexibility in production processes and reduces capital expenditures.   

In addition to the targeted selection of the components, absence of leakage plays a major role, especially during downstream operations. In this context the basic rule applies that the closer the relevant process is located to the stage of final filling, the higher the potential damage caused by system leakage, as the substances have already passed through a production process of several months before reaching the final filling stage. Therefore, when assembling the aforementioned components into a SUS, cable ties or comparable alternatives should not be used in the final filling stage or preceding processes, as these interfaces are a frequent cause of leakage.

With its overmolding technology Parker Prädifa offers a reliable alternative for connecting tubes by means of T, Y or X modules for silicone and TPE materials and has the additional capability of overmolding various plastic components such as connectors or filters. So-called reduction overmolding for reliable and leakage-free connection of tubes having different outer diameters, as well as customer-specific solutions such as the connection of bags to tube systems or overmolding of plastic containers in the area of the closure cap to prevent the cap from opening, are possible as well. 

Download Brochure

Components and Systems for the Pharma Industry and Medical Technology

Article contributed by
Berthold Röhrich
Market Unit Manager Life Sciences
Engineered Materials Group Europe
Prädifa Technology Division

Innovative Clean Room Production Meets Demands of Medical and Pharmaceutical Industries

Overcoming Barriers to Single-Use Implementation

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Parker Prädifa offers a large number of combined pneumatic seals and wipers for the open groove of the EU system. By installing the right type of seal a wide range of applications can be covered with just one cylinder. Another advantage: Thanks to the open groove the seals are very easy to install and remove.

The available materials range from NBR, HNBR to FKM and TPU through to PA-based materials. If extreme resistances, dry-running properties or stick-slip-free operation are required, PTFE compounds or UHMW PE will be used. Further materials can be provided at the customer’s request. The wide range of available solutions can cover temperatures from -200°C to 260°C at a maximum speed of 1m/s.
Modified wiper geometries are available to provide protection against ambi-ent influences. Without additional expense to the customer they prevent in-gress of liquids or fluids, viscous media or slight deposits into the cylinder.
For anti-torsion piston rods with two flat sides special seals are available.
In case of harsh conditions the use of split versions is recommended. This means that the material can be optimally adapted to the function of the seal and the wiper lip.

For hygienically sensitive applications in the food processing industry or life sciences wiper lips without undercuts or indentations are available. If, in addi-tion, a bactericidal or fungicidal effect is required the seals can be made from a special TPU material with a formulation that counteracts the formation of cultures on the sealing surfaces over a long period of time. This also effec-tively stops the decomposition of the seal material.

Where elastomers and plastics no longer achieve a sufficient wiping effect metallic wipers are used. Thermal caking, ice, resins, slag, textile or paper dust as well as metal spray are reliably wiped off to keep the piston rod clean. This system can be snapped into the normal groove without any addi-tional effort as well.

The seals can be very easily installed and removed through the open groove. If the system seal has to be replaced this can – depending on the seal type –  typically be done without disassembling the cylinder and while the piston rod remains installed.

The housing, which is identical for all sealing elements of the EU system, allows easy refitting of the pneumatic cylinders for different requirements. The seals are installed into the open housings by means of a handling tool.

• Standard: Profile EU
• Dry running, aggressive chemicals, extreme temperatures: E7
• Harsh application conditions: Profile E8
• High temperatures: Profile E9
• High temperatures and risk of contamination by dirt: Profile EW
• Hygienically sensitive applications: Profile EN
  
   

Article contributed by
Roland Schüßler
Senior Application Engineer
Prädifa Technology Division
 

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For designers of electronics enclosures, conductive plastics offer the benefit of lighter weight coupled with cost effective injection molding. But for years, using traditional blended plastic pellet materials, the EMI shielding results were often inconsistent at best, leaving many engineers grasping for something better. There is a new single pellet alternative on the market, promising improved EMI shielding consistency, created using tightly controlled conductive material that delivers unparalleled EMI shielding performance and superior processing.

Parker Chomerics has solved the problem of inconsistent EMI shielding effectiveness in single pellet plastic systems with the processing found in PREMIERTM PBT-225, a conductive plastic pellet system with consistent EMI shielding. This novel material was developed by leveraging our materials science expertise in both EMI shielding and injection molding.

More shielding effectiveness, less weight

Metal to plastic conversions not only eliminate 35% of the housing weight (as compared to aluminum), but also provide up to a 65% cost reduction by eliminating secondary operations such as assembly and machining. PBT-225 is a single pellet, polybutylene terephthalate (PBT) based, electrically conductive plastic, making metal to plastic housing conversions not only possible, but usually the best solution for demanding electronics applications.

Why excellent hydrolysis resistance is important

Traditional multi-pellet cube blends consist of two or more material pellets, mixed at pre-determined ratios. The very nature of mixing separates materials, resulting in variations which can never really be eliminated.

O-rings are a universal seal throughout the world. However, some axial applications may benefit from a different sealing solution called a Press-in-Place seal, or PIP seal.

First, let’s define axial seal. “Axial” implies the seal is being compressed from top to bottom. In other words, the seal is pressed between two flat surfaces. One flat surface has a groove cut into it to retain the O-ring and limit compression. This may also be called a face seal.

Some face seal applications may not lend themselves ideally to an O-ring. One example is a face seal groove that is oriented vertically or upside-down. The O-ring may fall out of the groove, adding to assembly time, or even resulting in a pinched or damaged O-ring.

Another problem may be when an O-ring is used in a non-circular groove, or racetrack groove. The hoop stress of the O-ring causes it to rebound to its circular shape, not staying in the groove.

One solution is to undercut the groove with a dovetail angle; however the dovetail groove has its own challenges. They are more expensive to machine and polish. The angled corners can wear down after many seal replacements. Lastly, the naturally high ratio of O-ring volume to Gland volume can result in an overfilled groove.

The Press-in-Place seal is customized with self-retaining features built into the seal. Three different categories of PIP seals can allow for several options in axial applications:

• Diamond Seal
• H-Seal
• Extruded PIP

Each can have additional advantages, such as low compression force, high line of sealing contact, reduced material usage, dual sealing beads, and work in a wide range of existing groove conditions.

The Diamond Seal is arguably the most beneficial PIP seal for its many advantages. Its shape is a tall, thin profile, which has good contact pressure and requires less compressive force than an O-ring. The shape uses up to 60% narrower groove width for comparable seal heights. Additionally, the profile minimizes the amount of material used to make the seal, resulting in less weight. Intermittent retention and stabilizer ribs around the seal provide the necessary self-retaining and support needed in the groove. For the problem of an O-ring popping out of a racetrack groove, a custom Diamond Seal is molded to match the groove layout. The Diamond Seal is able to bend around a much tighter corner radii than a standard O-ring. The final benefit of the Diamond Seal is the ability to consolidate seals into a single element, resulting in few part numbers, reduced assembly errors and improved assembly speed.

The second type of Press-In-Place is the H-Seal. The main benefit over a diamond seal is its ability to retrofit an existing O-ring groove geometry. The H profile features two sealing beads, which adds stability if rolling is a concern. The second point of contact can add additional confidence for those requiring redundant sealing. Finally, like the Diamond Seal, a major benefit to the H-seal is the ability to consolidate several seals into a single solution. 

The final type of PIP seal is the Extruded Press-In-Place. The extrusion process results in a precision-cut seal having a flat face, with retention ribs on either the inner or outer diameters. Retention ribs are engineered to grab the groove wall, and can be designed for an existing O-ring groove or even a very narrow or wide groove. The extrusion process for PIP seals offers a significant tooling savings compared to molded PIP seal options. Another unique characteristic of the extrusion process is the lack of molding parting line, which is inherent in O-rings and other molded shapes.

Press-In-Place seals are available in nearly every material family and engineered for optimum size and configuration for each unique application. Extruded PIP seals can be as small as .500” inner diameter, or have an outer diameter as large as 19”. Molded PIP seals can be as large as 60 inches in diameter. Parker Application Engineers are happy to assist you with the right PIP seal design. Please contact us today via online chat or by email by visiting the Parker O-Ring Division website. 

This article was contributed by:

A common question fielded by Parker O-ring Application Engineers is “will a (insert polymer family) O-ring work with (insert chemical mixture).” Not a day goes by where I do not field this question in some way, shape, or form. Which, honestly, makes perfect sense, because chemical compatibility is one of the two most important factors in designing a seal, the other being size. Choosing the right compound can literally make or break your seal and to the general designer, this can be a massive undertaking. There are so many rubber compound families out there and hundreds and hundreds of chemicals, so how can you know whether your seal is going to hold up? Well, today, I hope to give you a simple, and quantitative way to figure that out.

Let’s start by showing you what Parker has to offer in the way of chemical compatibility information. The Parker O-Ring Handbook (ORD 5700) has an entire section dedicated to this and within it you will find hundreds and hundreds of chemicals. Section VII, Compatibility Tables for Gases, Fluids, and Solids, lists the specific chemical, the recommended Parker compound to use for that chemical, and then gives a general rating out of 4 for chemical compatibility for all polymer families. As explained on the first page of that section, a rating of 1 indicates “Satisfactory” compatibility, 2 indicates “Fair”, 3 indicates “Doubtful”, and a 4 indicates “Unsatisfactory”. In general, a 1 means the compound can be used in just about any scenario with the given chemical. A rating of 2 indicates that an interaction between the compound and chemical in a static seal is generally ok, but dynamic seals should be avoided. A 3 indicates that even a static seal is doubtful to work during an interaction between a given compound and chemical. Finally, a rating of 4 means you should avoid contact between an elastomer and that particular chemical if at all possible. An “X” indicates that there is not enough data for the interaction between a given chemical and polymer to make a clear rating. This makes finding a recommended compound for a single chemical very easy, but as you all might expect, that is not always the case. It is extremely common for a seal to see a variety of fluids at different times, in combination with one another, and even at different temperatures. Fortunately, there is a way to determine whether a polymer family will work in these more complex environments as well.

Let us take an example where we assume a seal is going to see a mixture of 50% water, 20% ethylene glycol and 30% anhydrous ammonia. How would you determine what compound family would be best for this seal? A good rule of thumb is to use this method with EPDM, Nitrile and FKM. These three represent the general spectrum of chemical compatibility. EPDM is more compatible with water-based chemicals, FKM is more compatible with oil/hydrocarbon based chemicals, and nitriles are somewhere in the middle. 

Let’s take this approach for this example. First, we want to determine the rating for FKM in each of the listed chemicals. There are many different “types” of water in Section VII of the O-ring handbook (DI Water, boiler feed water, seawater, etc.) but for this example, let’s take regular water. If we find where the “water” row and “FKM” column intersect, you will find that it is given a 2 rating. Record this number; we will use it later. Next, find “ethylene glycol” and determine where that row and FKM meet and you will see this is also given a 1 rating. Finally, let’s look up FKM’s compatibility with anhydrous ammonia. Using the same method, you will find that it is given a rating of 4. As a general rule, if any chemical in the mixture has a rating of 4 or X (for no data) with a given polymer family, you should not use that polymer as a seal for the application, no matter how little of the mixture it makes up. Regardless, let’s proceed with the calculation to determine FKM’s compatibility with the mixture.

The general principle is to multiply the respective decimal values of the chemicals’ % composition in the mixture with the rating given between those chemicals the polymer family. So for FKM the calculation would look as follows:

0.5 * 2 + 0.2 * 1 + 0.3 * 4 = 2.4

All the decimal values should add up to 1 (or 100% of the mixture) and the rating scale is the same as the scale for individual compounds. If every chemical had a 1 rating with a given polymer, the final value would also be 1. If every chemical had a 4, the final value would be a 4. The closer the final value is to 1, the better. In this case, even though 2.4 isn’t a relatively high value and might be acceptable in some cases, we would not recommend FKM because it has a 4 rating with anhydrous ammonia.

Let’s repeat this calculation for Nitrile and EPDM. For nitrile, you can use the same method to find that it has a 1 rating with water, 1 for ethylene glycol, and 2 for anhydrous ammonia. The calculation for nitriles compatibility would be

0.5 * 1 + 0.2 * 1 + 0.3 * 2 = 1.3

A rating of 1.3 is a very good rating and we would expect Nitrile compounds to work well with this mixture. Let us do the same calculation with EPDM to see if it may be even better than nitrile. When you look at the compatibility ratings for EPDM with water, ethylene glycol, and anhydrous ammonia you will find that it is given a rating of 1 in each of those chemicals. This makes the calculation extremely simple

0.5 * 1 + 0.2 * 1 + 0.3 * 1 = 1

We would expect any general purpose EPDM compound to be the best polymer family to use in application with this specific mixture.

There are some cases where other polymer families, such as Butyl, Hydrogenated Nitriles, Neoprene, Polyacrylate, etc may be the “best” for a given application, but these are usually in cases where the seal may come in contact with very specific chemicals or other application considerations. As a general rule, starting with performing the described calculation on the three polymer families above will give you one of them that is “most compatible” and a good starting point.

For any specific questions, or if your calculation shows that none of these polymers are very compatible with the given mixture, please contact our Parker O-Ring Applications Engineers via our live chat service on Parker O-Ring Division's website.

Article contributed by Tyler Karnes, Applications Engineer, Parker O-Ring Division.

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Cam and groove style couplings, commonly referred to as camlock fittings, are used across many industries due to their ability to quickly connect and disconnect from holding tanks, pumps, filters, or other equipment. Although the nature of the camlock design makes it economical and rather simple to use, Parker’s engineers have found a way to improve the design even further with the DB CamLockseal. 

The standard sealing element commonly used in a camlock fitting is a rectangular cross section flat gasket. Since these flat gaskets are a solid chunk of rubber, they can be extremely difficult to compress when using the cam and groove locking mechanism of the fitting. An abnormally high closure force can sometimes result in an incomplete connection which, many times, results in leakage. Also, when compressed, the flat gasket geometry provides a broad but very low seal pressure across the mating substrates.

Parker DB CamLock Seal design features:

• Dual seal bead
• Increased maximum seal pressure
• Reduction of damaging seal stresses
• Reduced compressive load
• Excellent retention fit
• Color-coded materials

Compared to the standard flat gasket, the innovative Parker DB CamLock seal offers several improved features starting with the dual bead design. The dual bead feature provides redundant seal points which can be useful if damage were to occur to the primary sealing bead during operation. Having that second sealing bead can keep the fitting leak free and operational until a replacement can be sourced. 

The DB CamLock design also increases maximum seal pressure on the fitting hardware by approximately 55%. This increase in seal pressure provides a much better barrier to potential fluid passing by the seal. Having a higher seal pressure acting on the substrates, while reducing areas of significant harmful stress, reduces the chances of seal damage, increasing your seal life. 

Upon use, one of the most evident features of Parker’s DB CamLock seal design is the reduction of clamping load required during connection of the fitting. Using state of the art Finite Element Analysis (FEA), you can expect a reduction of closure force around 40% over traditional flat gaskets. A lower clamping load helps to ensure a complete connection which is essential to preventing leaks with cam and groove couplings.  

Another necessity for eliminating leakage in camlock couplings is making sure the sealing element is present. The DB CamLock seal design provides an excellent retention fit and is available in all standard size camlock assemblies. Therefore, you don’t have to worry about the seal falling out during transport. 

Lastly, the DB CamLock seals are available in material families that are commonly used in many fluid handling applications with a color-coded format. This allows an operator to be able to easily identify the seal material being used in a coupling by simply identifying the color.  

Common seal compound offerings for the DB CamLock seals are:

We've all done it at least once: looked at a report, read the numbers on it, and come up with exactly the wrong conclusion. Pass / fail limits and results are printed right there, but for some reason, our brain just misinterprets the two. It's a passing value, but for some reason we think it shows a failure instead. Imagine a police officer writing a speeding ticket for driving 53 MPH on a road with a 55 MPH speed limit.

It's not a problem with the test itself, it's a problem of interpretation. That means the old carpenter's adage, "measure once, cut twice; measure twice, cut once" doesn't address the issue. The same issue of misunderstanding the values on a test report occurs in the rubber seal industry about once a month. Passing results are misinterpreted to be failing results, and good values are thought to be bad ones. Here are four of the most common test report misunderstandings I've run into. 

Most low temperature testing involves negative numbers and that creates some confusion when coupled with “greater than / less than” test limits. For example, it is common to see pass / fail limits for TR-10, glass transition (Tg), and sometimes impact brittleness expressed in the form of “-30°C max.” I’ve talked to people who claim that a result of -32°C failed against a limit of “-30°C max” because everyone knows that 32 is a bigger number than 30. Just to be clear, -32°C passes, -28°C fails. This is a 2nd grade math problem, but sometimes we adults forget how to do the simple things if we don’t do them often enough. If this gets confusing, the easy way to interpret temperature limits is to mentally replace “max” with “no warmer than” and “min” with “no colder than.”

Compression set is always expressed with a maximum limit, for example, 20% max. Therefore, all values up to and including 20% are passing values. I’ve heard people claim that a result of 20% fails against a limit of 20% maximum because it’s not below the maximum. I won’t disagree that “barely passes” isn’t a good situation to be in, but “barely passes” is still a passing value. Compression set is a measure of what percent of the original squeeze has been permanently lost. A value of 100% means the material has gone completely flat. A value of 0% means the material returned all the way to its original dimension. With compression set, small numbers are good, big numbers are bad.

Commonly used in the passenger car and commercial truck industries, Compressive Stress Relaxation (CSR) is a measure of how much spring force the rubber has left after aging or being exposed to a fluid. The limits are always expressed as “10% min retained load force”, as one example of a common limit. CSR moves in the opposite direction as compression set, and perhaps this is why a result of 15% is frequently and incorrectly thought of as failing a “10% min” limit. For CSR, the more retained seal force, the better.

Most limits for tensile strength and elongation change after heat aging and fluid immersion are one-sided limits, meaning they only have one limit, not two. For example, a heat aging requirement may have limits of “-30%” or “-30% max” for the tensile strength change. What happens if the result is +2%? In other words, what if the result has the opposite sign from the limit? This is a passing result. There is no implied “to 0” limit attached to these one-sided limits. There is also no implied “mirror image” limit with the opposite sign. By this I mean that a “-30% max” limit does not automatically include a matching “+30% max” limit. A result of +100% is still a passing value compared to a one-sided limit of -30% max. If a specification does not explicitly call out a two-sided requirement with both a high limit and a low limit, then it only has one limit.

This is something that happens frequently, but it doesn't make it any less embarrassing. In an ideal world, someone is there to patiently explain the data and the limits and show how the report actually shows passing data, not failing data, and does so in a way that doesn't make you feel worse about it. If I have been that person for you in the past, a thank you cake would be appreciated. You and I know who you are, but we can keep that to ourselves. Cookies are good too.

For more information on the proper way to read a test report, please contact the engineers at the Parker O-Ring & Engineered Seals Division. 

This article contributed by Dan Ewing, senior chemical engineer, Parker Hannifin O-Ring & Engineered Seals Division.

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What are the premium requirements of gaskets for flange-to-flange aerospace assemblies such as antennas, access panels, radars and lighting? Electrical conductivity? EMI (electromagnetic interference) shielding? Fluid and pressure sealing? Galvanic corrosion mitigation? In short, the answer is all of these things and more.

For this reason, designers choosing fully-cured, urethane-filled expanded aluminium gaskets will not only find a solution that meets all of these criteria, but one that offers numerous performance improvements when compared with alternative sealing solutions. In fact, users can expect a 33% lower total cost of ownership (TCO) resulting from the avoidance of assembly rework and material replacement.

The gasket material! Impressive levels of electrical through-resistance, shielding effectiveness, corrosion resistance and fluid resistance, as well as an extensive temperature operating range are all attributes of the latest urethane-filled expanded aluminum gaskets. 

For any design engineer, the foremost consideration of a gasket is sealing performance. Here, the high conformability of low-modulus urethane binder systems adapts to surface irregularities to ensure leak-path elimination and efficient sealing characteristics.

Gasket materials must also perform well in terms of both atmospheric pressure and fluid sealing, and again urethane-filled expanded aluminium gaskets perform well. The high surface affinity and conformance associated with urethane binder systems creates an efficient sealing solution in variable applications such as those found between externally mounted aircraft devices and the fuselage. When subjected to specified torque values for such devices, pressure sealing of circa 2.8 bar should result, while also providing sealing capabilities and chemical resistance against common aviation fluids.

Among other major gasket functions is electrical conductivity, as lightning strike survivability and EMI shielding (to avoid antenna signal interruption) are paramount. Expanded aluminium improves upon electrical performance compared to particle-filled or woven mesh alternatives by eliminating the electrical contact resistance associated with point-to-point conductance requirements. The homogenous nature of expanded metal results in a highly efficient electrical system which optimizes attenuation and electrical grounding performance.

So what of airframe pitting? Clearly, it is vital to avoid the surface pitting of airframes and any associated stress fatigue and cracking. Here, 3000 series aluminium alloys offer a notable advantage. When these materials act as the gasket’s conductive medium, they become the sacrificial entity of the assembly when interfaced with harder aluminium components. Expanded aluminium also promotes an even distribution of interfacing surface load, resulting in the elimination of concentrated stress points that can increase pitting occurrence. Microscopic inspection of substrates after gasket deflection shows no negative interaction with expanded metal-based gaskets. Conversely, woven-wire based solutions can create stress points at wire-overlap locations that cause surface pitting.

With regard to minimizing aircraft TCO, the mitigation of corrosion is a significant contributor. Using urethane-filled expanded aluminium gaskets, moisture ingress, and the resulting electrolytic environment, can be minimized through increased sealing performance. Additionally, as aluminium is the typical base material for substrate design, deploying 3003 expanded aluminium as the gasket’s conductive medium galvanically matches the sealing solution with the mating assembly. In these two ways, aircraft owners can expect significant reductions in rework and component replacement requirements commonly associated with corrosion.

Finally, installation is straightforward thanks to a symmetrical gasket cross section. This allows for gasket installation without consideration of Z-axis orientation, thus allowing process yields to improve.

For more information pertaining to urethane-filled expanded aluminum gaskets, please contact the Chomerics Division.

This article was contributed by Jarrod Cohen, marketing communications manager, Parker Chomerics Division. 

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We’re thrilled to announce that Parker Hannifin Chomerics Division was presented with Boeing’s Advocacy Award at the 2016 Boeing Supplier of the Year Awards. Accepting the award were Scott Gunderson, global aerospace/defense market manager and Brian Mahoney, global business unit manager both of Chomerics Division.

Chomerics Division received the award due to its superior performance in supporting the renewal of the US Export-Import (EXIM) Bank. A former Navy P-3C and T-45C pilot, Gunderson spoke to key congressional representatives about the need for the EXIM Bank, addressing a large audience of Boeing and supplier representatives, including Boeing Chairman, CEO, and President Dennis Muilenburg. The bank, formed to help third-world countries obtain low-cost loans to purchase American goods like airplanes, was later approved by congressional vote. Chomerics supplies Boeing with EMI shielding gaskets and other technologies.

Tim Keating, senior vice president of government operations for Boeing, publicly recognized and praised Parker Chomerics and Gunderson at the event.

“We at Chomerics are honored to receive this recognition by Boeing. It’s an acknowledgement of the outstanding quality of work by the Parker Chomerics team and reflects our ongoing commitment to excellence in serving our customers.” David P. Hill, global general manager, Parker Chomerics.

The influence of suppliers like Chomerics Division engaging with policy makers can foster awareness that provides multiple benefits.

“Our supplier network is one of Boeing’s greatest competitive advantages when it comes to advocating for our shared interests,” said Kent Fisher, Boeing’s leader for enterprise supplier management. “Suppliers like Parker Chomerics represent a critical business voice to help decision makers understand the incredible impact that the aerospace industry has on their economies, employment and communities.”

The Boeing Supplier of the Year is the company's official program to recognize suppliers who achieve the high performance standards necessary to meet customer expectations and remain competitive in the global economy.

Learn more about Parker Chomerics’ products:

• EMI Shielding
• Thermal Interface Materials
• Integrated Display Solutions

This article was contributed by Jarrod Cohen, marketing communications manager, Parker Chomerics Division.

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Careful management of thermal interfaces is crucial to maintaining the reliability and extending the life of electronic devices and equipment. As each new electronic product generation requires higher power in smaller packages, the challenges associated with thermal management become more and more intense.

THERM-A-GAP GEL45 is Parker Chomerics' latest high performance, fully cured, dispensable thermal gel, designed for dispensing over heat generating electronic modules to transfer the heat from the component.

The gel is purpose-designed to eliminate time consuming hand assembly, decrease installation costs and reduce the complexity of customer manufacturing and purchasing functions. It is especially suited to automotive ECUs (electronic control units), consumer electronics, flat panel displays, power supplies, semiconductors, memory modules, power modules and microprocessors/graphics processors.

Chomerics GEL45 is a silicone-based cross linked compound loaded with thermally conductive fillers which form a low-modulus gel. The material is supplied fully cured, eliminating the need for mixing and post-application heating and curing operations. The highly conformable gel provides low thermal impedance at thin and thick gaps, allowing use of common heat spreaders. Another benefit of GEL45 is that it deflects easily under very low compressive forces, which minimizes the stress on the component, and therefore reduces failures. 

THERM-A-GAP GEL45 is easy to dispense for compatibility with high speed automated processes and offers a high tack surface. Furthermore, it can accommodate a variety of bond line thicknesses (0.089mm minimum) for successful application to multiple devices.  

Here are the 6 main advantages of using Chomerics GEL45.

• Offers excellent price-to-performance ratio
• Proven long term reliability, especially in harsh operating environments
• Low thermal impedance
• Easy to dispense
• High thermal conductivity of 4.5 W/m-K
• Supplied fully cured

Chomerics has a successful history of providing thermal materials expertise and commitment to developing new, high performance materials to meet the challenges of today’s design engineers.

Gel45 is supplied in a variety of convenient ready-to-dispense containers. Please contact Parker Chomerics for more information.

Learn more about Chomerics thermal interface materials.

This blog was contributed by Melanie French, marketing communications manager, Parker Chomerics Division Europe. 

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Customer demand and government regulations continue to push the automotive industry to improve efficiency, and many of these improvements affect seal materials and seal material selection. But how and why would this impact the seals in a vehicle? It may surprise you how far reaching many of these changes extend.

In general, efficiency improvements can be lumped into one of several categories: engine improvements, transmission advances, electrification / hybridization, aerodynamics, weight reduction, and accessories. I’ll focus primarily on advances in engine technology that are causing the industry to reassess seal material selection, in some cases dramatically.

Engine modifications can be boiled down to a single phrase: “Do more with less". Go further on a gallon of fuel. Or to put it another way, create the same amount of usable horsepower and torque with a smaller engine that burns less fuel. They’re two sides of the same coin. There are many ways to squeeze out efficiency, and most of them place increasing demands on elastomer seals.

One “trick” auto manufacturers have been using for several years is to use lower viscosity engine oil. This reduces the amount of power needed to pump oil throughout the engine, which means less of the engine’s power gets used up running itself. Synthetic 0W16 oils are now entering the market, with further reductions on the horizon. These ultra low viscosity oils are increasingly aggressive to the polyacrylate (ACM), ethylene acrylic (AEM), hydrogenated nitrile (HNBR), and Type 1 (“standard”) fluorocarbon (FKM) elastomers that have traditionally been used in engine oil applications. They have minimal impact on Type 3 (low temperature) FKM materials such as Parker’s VG292-75 and V1289-75 compounds, but these materials are more expensive than the incumbent materials. Will lower viscosity oils push car manufacturers to upgrade the seals used in engine oil applications?

Another engine improvement is the increasingly widespread use of Gasoline Direct Injection (GDI) and Turbodiesel Direct Injection (TDI). In these engine designs, fuel is precisely measured and injected directly into the combustion chamber rather than into the intake air. Pressures in the injection system must be higher than the pressure inside the combustion chamber, which currently means fuel system pressures up to 50 MPa (7,000 psi). The GLT and GFLT-type fluorocarbon compounds that have been used for the last several decades are simply not capable of meeting the high pressure and low temperature demands coupled with the need for improved resistance to methanol and biodiesel. Enter Parker compounds VG286-80 and VG109-90. Both materials offer improved low temperature performance over GLT-type FKMs and resistance to methanol and biodiesel that’s almost as good as the GFLT-type materials, plus pressure resistance that reaches to 70 MPa (10,000 psi) or higher.

A third engine improvement is the expansion of turbocharging. Popular among high performance sports cars and race cars, turbocharging offers the higher horsepower and torque of a larger engine in a smaller, lighter, more efficient engine block. Power is available when needed, but not wasted during light duty cruising.

However, turbochargers get hot. Hotter than elastomers can typically withstand for any length of time. So, standard designs run engine coolant to the turbocharger, but that presents another challenge: the elastomers that work best in high temperature applications aren’t very resistant to hot water and glycol coolants. There are, however, notable exceptions. Parker’s VG292-75 and VG310-75 fluorocarbon compounds offer outstanding coolant resistance and thermal stability up to 200 °C. For even more aggressive applications, Parker’s FF400-80 perfluoroelastomer can cover the range of -40 to +250 °C with good coolant resistance, but that level of high performance comes with a high performance price tag, as well.

Vehicle designs are pushing the limits on fuel economy, and these advances are placing increasing demands on rubber seals. Fortunately, Parker already has solutions for many of these challenging applications available and in production today. For additional information on the best material to solve your sealing challenges, please contact our engineers via online chat at Parker O-Ring & Engineered Seals Division. 

This article contributed by Dan Ewing, senior chemical engineer, Parker Hannifin O-Ring & Engineered Seals Division.

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