Field reliability of Ricor microcoolers

Over the recent 25 years Ricor has fielded in excess of 50,000 Stirling cryocoolers, among which approximately 30,000 units are of micro integral rotary driven type. The statistical population of the fielded units is counted in thousands/ hundreds per application category. In contrast to MTTF values as gathered and presented based on standard reliability demonstration tests, where the failure of the weakest component dictates the end of product life, in the case of field reliability, where design and workmanship failures are counted and considered, the values are usually reported in number of failures per million hours of operation. These values are important and relevant to the prediction of service capabilities and plan.