From O-Rings to PIP Seals: Mastering Seal Selection for Any Application
MASTERING SEAL
SELECTION
Seal rings are an essential component in a wide variety of applications, providing critical solutions for maintaining system integrity and preventing fluid leaks. However, choosing the right seal for an application can be a complex task. While the question “What is the right seal for my application?” may seem simple, the answer often requires careful consideration of various factors. In this blog, we’ll explore the different types of Parker seal rings, from the classic O-ring to advanced Press-In-Place (PIP) seals, and how to optimize your selection for any given application.
Understanding Seal Selection
Before diving into specific seal types, it’s important to understand the critical factors that influence seal selection. The process begins by asking key questions:
– Is the seal for a static or dynamic application?
– Is it a face seal or a radial seal?
– How will the seal be installed during assembly?
– What options exist for seal retention?
– Is there enough room for a gland in the mating hardware?
– Will the component require regular servicing, or is it sealed for life?
– Is redundant sealing necessary, and does the seal need to be replaceable?
– What is the production volume, and can multiple components be integrated into a single item to reduce complexity?
These questions form the foundation for choosing the correct seal, narrowing down the decision to meet the specific needs of your application. In the end, the right seal is often the simplest one that fulfills all the requirements, aligning with the principle of Occam’s razor.
The Classic O-Ring
One of the most widely used and versatile seals is the O-ring. Its round cross-section and round footprint make it an elegant solution that has been trusted to prevent fluid loss for over a century. O-rings are manufactured in vast quantities across a wide range of materials, making them a go-to choice for both static and dynamic applications.
Standard O-rings are capable of withstanding high pressures and can provide years of leak-free operation if properly designed. They are also available in standard sizes, eliminating tooling costs and reducing lead times. From a cost perspective, O-rings are often the lowest-cost solution for many applications.
However, O-rings have some limitations. One of the most significant challenges with O-rings is the need for dovetail grooves to retain the seal during assembly, which can be difficult to manufacture. Additionally, O-rings require smooth surface finishes (16 RMS for gases and 32 RMS for liquids) to ensure a proper seal, and they demand high closure forces to compress the material. Moreover, once the joint is assembled, verifying that the O-ring is correctly installed can be challenging.
Press-In-Place (PIP) Seal Selection
The Press-In-Place (PIP) seal is a more advanced solution that addresses some of the shortcomings of the O-ring. PIP seals are small cross-section, homogeneous rubber shapes that can be molded to match complex gland geometries, including branched seals. This makes installation easier, allowing the seal to “drop in” without the need for multiple O-rings.
PIP seals often include retention features that eliminate the need for dovetail grooves, allowing for secure retention in a straight-wall groove. This simplifies the manufacturing of the mating hardware, as the groove required for a PIP seal is narrower than the wide, rectangular groove needed for an O-ring. The smaller footprint of PIP seals also reduces closure force, making them an excellent alternative in applications where O-rings may not be ideal.
Parker’s precision-cut PIP seals offer enhanced seal retention and installation efficiency compared to traditional static face seals. These seals are custom-designed to fit into complex groove patterns without requiring stretching or additional retention methods. They are engineered to withstand a wide range of environmental conditions, including exposure to various fluids, pressures, and temperatures, making them a reliable solution for many industries.
Elastomeric Seals with Retainers
In some applications, it may not be feasible or desirable to have a groove in the mating hardware. For these scenarios, a seal that creates its own gland is needed. This type of seal construction features an elastomeric seal bonded to a rigid substrate or “retainer.” These seals come in two primary configurations:
- Edge-bonded seals (Integral Seals): These seals use a retainer to limit compression and prevent the seal from being overstressed. The mating hardware is bolted together around the seal, creating a stable interface perfect for high-demand applications. The retainer also simplifies installation by making the edge visible after assembly, providing visual confirmation that the seal is in place.
- Volume/void seals (Gask-O-Seals): These seals are similar to edge-bonded seals but are designed for higher compression applications. Like the Integral Seal, Gask-O-Seals can incorporate multiple port sealing into a single retainer, reducing bill of materials complexity and preventing assembly errors.
These types of seals can also handle rougher surfaces, sealing surfaces with up to 125 RMS, and they can withstand higher pressures than traditional O-rings. Their ability to incorporate multiple sealing points into one retainer makes them an excellent choice for complex assemblies that require precise, robust sealing solutions.
Turnkey Seal selection
For applications that require a truly comprehensive solution, Parker offers the option to incorporate the seal directly into the mating hardware. A special configuration of the Gask-O-Seal, this method involves vulcanizing an elastomeric seal directly onto a structural component, such as a housing or cover. By bonding the seal into the groove, a tangential leak path is eliminated, improving system integrity.
This type of turnkey solution can include additional features such as inserts, captive fasteners, or even surface finishes like anodizing or painting. The result is a reduced part count and simplified installation, which is especially beneficial for high-volume manufacturing environments. In short, this solution streamlines the production process while providing robust, long-lasting sealing.
Specialized Seal Solutions
While O-rings and PIP seals are common solutions, Parker offers additional options for more specialized applications. One example is the Jigsaw Extruded Seal, designed for large joints or multiple grooves. The Jigsaw design features precise interlocking technology that simplifies installation and reduces the need for RTV (room-temperature vulcanizing) silicone, splicing, and inventory management. Jigsaw seals are self-retaining and require only one part number for multiple joints, making them a cost-effective and time-saving solution.
Low-Closure Force Static Seals are another specialized option. These seals deliver reliable performance with less compression, making them perfect for lightweight parts or large surfaces. Durable and customizable, LCF seals are ideal for industries like aerospace and automotive, where efficiency and easy installation are crucial.
Another innovative solution is the Hollow Keyhole Extrusion Seal, designed to provide high compressive forces while accommodating the industry’s demand for easier installation and reduced component weight. This design reduces bolt loading and maintains seal reliability while generating lower compressive forces, making it ideal for low-pressure applications.
Finally, Extruded Hexapod Seals are another solution for applications requiring high retention at lower pressures. These seals are easy to install, eliminate the need for standard size tooling, and are a perfect choice for large enclosures, such as electric vehicle batteries or heavy-duty engines.
A&C Engineering: Your Parker Seal Distributor
At A&C Engineering, we are proud to be a Premier Distributor of Parker, offering a comprehensive range of sealing solutions. Whether you’re in need of O-rings, PIP seals, or custom-designed sealing solutions, we have the expertise to help you find the ideal seal for your application. Our team is ready to assist with any questions or concerns you may have about seal selection, installation, and performance.
If you’re interested in purchasing Parker seals or learning more about which sealing solution is best for your needs, don’t hesitate to reach out. Contact us at A&C Engineering for personalized assistance and advice.
Conclusion
Choosing the right seal is essential for ensuring the performance, reliability, and longevity of your system. From the simplicity of O-rings to the advanced capabilities of Press-In-Place seals, there is a wide range of options to meet the needs of various applications. Working with a knowledgeable manufacturer like Parker ensures you get the optimal seal type for your specific requirements.
For more information on Parker’s sealing solutions or to make a purchase, contact A&C Engineering, your trusted Parker distributor, at sales.parker@ace-engineering or 0031-(0)187 49 70 80.
Links
OES 7005 Hollow Keyhole Extrusion for Battery Cover Seals PDF
