The History of a High Efficiency Valve from Concept Through Field Acceptance

As a result of research done in the early '70's on the loss mechanisms and causes of failure in compressor valves, a new line of valves was designed and developed, The new line of valves has losses less than one-third the losses in earlier valves and is also more reliable. This paper outlines the basis for the improvements in efficiency and reliability, and describes the development process leading to the efficient, reliable valve now in production. This development process took over 10 years including laboratory development and e~tensive field testing. INTRODUCTION In 1974, Dresser-Rand engineers decided to take a new look at losses in compressor valves and discovered that large decreases in the losses were possible with relatively small changes in valve design; specifically using seats with narrower slots to incr~as~ th@ flow area through the guard. About the same time, the use of non-metallic plates in gas field compressors was starting. These have several advanta~es including the ability to run with higher impact velocities and hence avoid the necessity of using the very low lifts required with steel plates at gas field compressor speeds (about 1000 rpm). A new valve design was started to utilize these two advances. 5-1/4" prototype valves built in 1975, were used to test the efficiency of the new valve under field conditions and a very significant improvement was seen. The prototype valves were then left in service to determine the reliability of glass filled nylon plates at • 140" lift. Preproduction valves in 5-1/4" and 7-1/2" sizes were then manufactured and an e~tended field test with 162 valves was started. Severe reliability problems were encountered with the plastic plates used at that time. These were eventually solved through changes to the plate thickness, the spring button material, the spring pattern and improvements to the composition and manufacture of the plates. The HPS valve (U.S. Patent #4,184,508 and 4,307,751) was first used in a low speed gas compressor in 1982 and was released for production in 1985. It is now widely used in gas gathering, gas lifting, enhanced oil recovery and refinerv compressors. Improvements to the valve have continued to be made since the . initial preproduction valves were made. In particular, the plate material has been changed to a specially formulated, carefully manufactured, Peek based material and to allow operation of high pressure valves at high speeds, the springs have been redesigned to prevent their going solid. Quality control has also been improved to prevent reoc~urrence of som~ of the starr up problems encountered.