case studies
The VICTREX® PEEK™ polymer family of thermoplastic products has helped make important advances in the exploration and production of energy, particularly oil and gas.
A range of applications incorporating VICTREX PEEK polymer have provided longer equipment service life in more severe conditions, including higher temperatures and pressures. It has been instrumental in helping companies achieve higher production rates, reduce downtime, and lower maintenance requirements.
Clifford Spring: Energy-Absorbing Springs
The Challenge
The Clifford Spring Company based in Redditch in the UK, with over 40 years experience in manufacturing energizing springs for the oil and gas sector, was faced with the task of creating an energy absorbing spring that was non corrosive and chemical resistant with high and low temperature performance. A high occurrence of wear and damage was also a consideration.
Seals and backup rings, a necessary addition to the metallic energy absorbing springs, typically face the challenge of weakening over time, which in extreme circumstances, if the seal wears, can come in contact with and irreparably damage the shaft. Seal lipping, due to parts being manufactured separately, often leads to shorter seal, backup ring and spring life.
The Solution
Clifford Springs has developed a solution to these challenging problems, producing energy-absorbing springs using VICTREX® PEEK™ polymer.
“The major benefits of using an energy absorber made with VICTREX PEEK are that corrosion is eliminated in ferrous-based energy absorbers and the absorber made with VICTREX PEEK polymer resists virtually all aggressive chemicals, solvents and lubricants used within the oil and gas industry,” said John Clifford, managing director at Clifford Springs. “Further, if the seal should become worn and the energy absorber component is made from the same material as the seal itself, then there will be no damage to the shaft.”
An additional benefit of using VICTREX PEEK polymer is that the overall weight of the seals is reduced due to the elimination of metallic components, eliminating issues with differing rates of thermal expansion as both the seal and the energy absorber have the same coefficient of thermal expansion.
The energy absorber spring made with VICTREX PEEK polymer can be manufactured as a totally encapsulated item, or as a Garter type spring where the spring can be added to the seal as a secondary operation, following molding or machining of the seal.
The energy absorbers are produced from VICTREX PEEK monofilament extruded by Zyex Ltd of Stonehouse in the UK, a facility that is capable of spinning VICTREX PEEK filaments from over 2mm down to 10 microns in diameter.
Zyex has more than 20 years experience in producing such monofilaments, multi-filaments and staple fibres. Their exacting standards mean that VICTREX PEEK can also be woven into extremely fine meshes and used as filters in chemically aggressive hot environments and braided into cable harnesses to give protection from abrasion in demanding oil and gas and aerospace applications.
The total encapsulation method carried out by the seal manufacturer prevents the seal lipping out and therefore prolongs the life of the seal. A further advantage of having a thermoplastic spring in the Garter type of seal is that the monofilaments can be produced in virtually any color in the spectrum, allowing instant identification ensuring the correct energy absorber has been fitted to the seal.
The energy absorbers made with VICTREX PEEK polymer are available with an outside body diameter of 1.40mm up to 10.00mm. The maximum single length that can be produced is 2.4M, this equates to a spring diameter of approximately 750 mm. multiple springs can be joined end to end to give a larger spring diameter.
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