2008-08-26 23:48:03 -

- A production beta version of a compressor plate valve developed at Southwest Research Institute is demonstrating long operating life in real-time field conditions. The SwRI Semi-Active Compressor Valve, developed in 2006, is currently installed in a high-speed compressor at a natural gas production site for a long-term field performance test.

The single largest maintenance cost for a reciprocating

compressor is compressor valves. These machines typically use passive compressor valves, which experience high plate impact velocities that often result in fatigue failures and a short operating life, leading to frequent replacement.

The SwRI Semi-Active Compressor Valve increases plate life by drastically reducing plate impact velocities. Rather than springs, the design uses electromagnets to actively control impact velocities. The valve plate starting motion is sensed using an electric inductive motion sensor controlled by the electromagnets, thus eliminating the need for pressure transducers or shaft encoders to control plate motion.

"Four production version valves were installed in a high-speed compressor in early April 2008 and have been performing with no valve failure to date, far exceeding the performance of conventional valves in place at the same location," said Dr. Klaus Brun, manager of the Rotating Machinery Section in SwRI's Mechanical and Materials Engineering Division and principal developer of the valve.

"This compressor, which is performing a gas gathering application, is operating at 1,350 rpm with a compression ratio of 3:1 under harsh conditions," Brun added. "During this time several of the conventional valves have been changed out. Each of the SwRI valves has now accumulated more than 3,000 operating hours at full load and full speed. To have our valves run in this compressor under these conditions without failure is quite an achievement. We also added a capacity control feature to our design, which means the valve can now be used to control flow, making it an even more efficient choice."

Plans call for additional valves to be installed at the compressor facility.

The valve, which earned a 2007 R&D 100 Award from R&D Magazine, was one of several technologies developed during the Advanced Reciprocating Compression Technology program, conducted at SwRI and jointly funded by the Gas Machinery Research Council, BP, and the U.S. Department of Energy National Energy Technology Laboratory. The latest version of the valve is being manufactured by SwRI and Cook Compression.

For more information about the Semi-Active Compressor Valve, contact Brun at 210-522-2249 or via email klaus.brun@swri.org.

SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 3,300 employees and an annual research volume of more than $501 million. Southwest Research Institute and SwRI are registered marks in the U.S. Patent and Trademark Office. For more information about Southwest Research Institute, please visit www.newsroom.swri.org or www.swri.org.

Southwest Research Institute, San Antonio
Deborah S. Deffenbaugh, 210-522-2046
dsdeffenbaugh@swri.org