As a specialist in engineered materials, engineering design and process technology Parker Prädifa offers an extensive portfolio of large-size seals and moldings made of polymers such as NBR, EPDM, FKM, PTFE and PEEK, as well as metal.Download Whitepaper
Elastomers, particularly rubber compounds with their diverse advantages – good long-term and chemical resistance in a wide temperature range, high wear and pressure resistance, rubber-elastic behavior, good availability – are among the most commonly used sealing materials in the chemical process industry. Parker Prädifa offers an extensive portfolio of high-performance polymers from the EPDM, NBR, FKM and FFKM family of materials for the most exacting demands also in large dimensions.
Innovative, Economical Production Method
The conventional production method of vulcanization for precision rubber seals such as O-rings is not economically feasible due to high tooling costs and other reasons. That is why XXL-size rubber seals are typically produced more economically by joining round cord stock using joint vulcanization or splicing to achieve the desired length. However, due to physical disadvantages, their utilization in safety-relevant components is not permitted. Parker Prädifa has developed continuous vulcanization, an innovative technology that makes it possible to produce precision rubber seals of any desired dimension without sacrificing quality and functional performance.
In addition to precision-quality XXL-size O-rings, Parker Prädifa offers the development and production of customer-specific geometries in large diameters. A wide range of materials is available according to the application requirements.
Using a new type of manufacturing technology, Parker Prädifa is able to produce machinable polymer seals from materials like PTFE, PEEK and TPU up to a diameter of 4.5 meters.
Fluoropolymers – PTFE
Seals made of the fluoropolymer PTFE are used where many other sealing materials (such as rubber elastomers, polyurethanes, fabric-reinforced elastomer seals, etc.) reach their limits in terms of requirements such as temperature range, chemical, friction and wear resistance. That is why PTFE is the most frequently used fluoropolymer in challenging sealing applications. Parker Prädifa produces PTFE seals – from pure PTFE and numerous modified compounds – in XXL dimensions with diameters of up to 4.5 meters using economical machining techniques.
PEEK and Other High-Performance Polymers
Under certain conditions, even fluoropolymers – especially at increasingly higher temperatures – reach their limits in terms of strength and mechanical resistance. For application conditions like these, Parker offers other materials such as the high-end material PEEK in the XXL range as well. Where the utilization of PEEK is not absolutely necessary, less costly materials such as POM, PE and diverse polyurethanes and elastomers are available. Parker Prädifa manufactures XXL-size seals with diameters of up to 4.5 meters from polymers and other materials using economical machining techniques.
Economical Machining of Polymer Seals
Polymeric materials such as PTFE, PEEK and others are suitable for machining techniques such as turning or milling. This makes it possible to manufacture both larger and smaller volumes because no additional tooling costs for molds are incurred. Parker Prädifa has continually developed the manufacturing technology of machining further and is now able to offer diameters of up to 4.5 meters at the highest level of quality.
Typical types of seals are so-called FlexiSeals® with a polymer jacket supported by a metal spring, lip seals in TPU or elastomer materials and chevron stacks combining several sealing elements in a sealing system for maximum performance. Bearings, guiding elements and bellows are possible as well.
When classic sealing materials – for instance in temperature ranges above 300 °C and below -50 °C – reach their limits alternative materials are required such as metal with appropriate coating/plating. Parker offers metal seals made of stainless steel or nickel alloys in C, E and other designs characterized by high pre-loading force and significant resilience. Drawing on many years of experience in the gas turbine market, Parker has continually expanded its expertise in large diameters and developed special problem solutions that substantially increase the efficiency of the machines.
C-seals: ≤ 3000mm
Spring-energized C-seals: ≤ 7600mm
O-rings: ≤ 1200mm
Heat-treated ≤ 2700mm
Segmented ≤ 7600 mm