X-Rings Quad Rings
X-rings (also known as quad rings or four-lobed seals) offer an alternative seal solution to O-rings for use in reciprocating dynamic or rotary applications.
X-rings are often used in applications where the seal is required to operate under lower pressure and temperature conditions. High sealing efficiency can still be achieved under low pressure with an X-ring as the mold parting line is not coincident with the primary sealing faces.
These seals can typically be retrofitted into existing O-ring grooves with the size often based around the original O-ring size. The square envelope of the X-ring stops the seal from twisting and rolling, preventing spiral failure often seen when O-rings are used in reciprocating applications. An X-ring can be manufactured to standard O-ring sizes, as well as custom sizes for specific applications.
X-rings can also offer a reduction in friction as trapped media between the lobes can provide lubrication to the sliding sealing face. For low pressure applications, the combination of a low modulus material and small cross section can help to reduce friction. In high pressure applications, the friction can be reduced by selecting a higher modulus material with a reduced coefficient of friction.
X-rings / quad rings for life-science applications
For X-rings used in food, dairy and pharmaceutical applications PPE offers a variety of elastomer material grades compliant with many international requirements such as FDA, USP Class VI, WRAS and 3-A in addition to metal detectable X-rings, all of which are free from Animal Derived Ingredients.
High performance materials
With an unrivalled range of elastomer materials available, PPE has an elastomer for every application, with performance characteristics that meet a range of temperature and pressure requirements, plus resistance to aggressive chemical media.

Perlast® perfluoroelastomers
expand_moreThe ultimate perfluoroelastomers for sealing applications where chemical resistance and high temperature performance are critical.

EnDura®
expand_moreThe ultimate range of elastomers for sealing applications in the world’s most aggressive high pressure environments.

Detectaseal®
expand_moreA range of X-ray and metal detectable elastomers for the ultimate contamination detection and containment.
Resources and Tools
Take a look at some of our PPE resources to help you identify the most effective combination of material and profile for your sealing requirements.
PPE material grades selection tool
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