29 Apr 2003
Victrex® PEEK™ polymer seal ring contributes to success of on-site-reparable compressor valve
Cook Manley of Stafford, USA, has developed the on-site-reparable MOPPET® compressor valve, featuring a Victrex® PEEK™ polymer seal ring. With its inherent long-term dimensional stability, flexural properties, fatigue and wear resistance over a wide range of temperatures and pressures, the polymer contributes to the valve’s proven success in petrochemical and natural gas installations.
Compressors used in these demanding industries have to operate in a variety of environments, ranging from vacuum refrigeration to very high temperature, high pressure refinery processes. Unlike nylon, which can only withstand temperatures up to 140° C-145° C depending upon the type of pressure being applied, Victrex® PEEK™ polymer delivers high temperature performance up to 250° C over a wide pressure range.
It is essential that the valves maintain dimensional stability while in the end-use customer’s inventory. When compared to materials such as nylon, which is inherently hygroscopic, PEEK™ polymer has extremely low moisture absorption and is therefore very dimensionally stable.
Victrex® PEEK™ polymer’s excellent fatigue and flexural properties are also important to this application. “When a compressor is running, it can become contaminated with dirt and liquids,” explains Mr. Parks, plant manger at Cook Manley, “Unless the seal ring is flexible, it can snap under these conditions. Whilst there are many materials that are flexible in nature, very few have the fatigue strength of Victrex® PEEK™ polymer. This is an essential property, as a seal ring has to bend and flex during millions of cycles per year, running at typically 300-330 rpm. Some compressors can operate up to 2,000 rpm."
Cook Manley has successfully used Victrex® PEEK™ polymer for many years for its radius-disc valves. The MOPPET® is in fact a series of individual radius-disc valves encapsulated in modular cartridges. The cartridges are interchangeable from valve to valve and from compressor to compressor, thereby minimizing end-user inventories.
The MOPPET® valves significantly reduce both maintenance costs and compressor downtime. Unlike traditional valves, which are typically sent back to shore for repair, these patented valves can be easily repaired on-site, with no specialist tools or training required.
However, with its combination of high mechanical strength and long-term fatigue resistance, Victrex® PEEK™ polymer contributes to the valve’s extended service lifetime. According to Bill Peterson, area supervisor for the Hanover Company, a large compressor rental company: “At one station, we were replacing OEM plate valves every week. We installed a set of Moppet® valves over a year ago and they are still going strong.”
Reader enquiries
Helen SwarbrickVictrex plc
Victrex Technology Centre
Hillhouse International
Thornton Cleveleys
Lancashire FY5 4QD
United Kingdom
Tel +44 1253 897700
Fax +44 1253 897701
United Kingdom
Notes for editors
Victrex plc, which has its sales, technical and production headquarters at Thornton Cleveleys in Lancashire, UK, had a turnover of more than £59m in the last financial year. The company exports 97 percent of its Victrex® PEEK™ polymer output to OEMs in the automotive, industrial, medical, food and electronics market sectors in Europe, North America and Asia Pacific.
Information on products, technical support services and sales and distribution contacts worldwide, can be accessed through the company’s web site: www.victrex.com
The PEEK™ Trademark
For many years Victrex plc has been using the PEEK™ trademark to refer to its brand of Polyetheretherketone. Victrex plc is the sole manufacturer and supplier of the Victrex® PEEK™ brand polymer world-wide. PEEK™ is a trademark of Victrex plc.
Related images
Victrex® PEEK™ polymer seal ring contributes to success of
on-site-reparable compressor valve
