Thales Cryogenics has an extensive background in delivering linear and rotary coolers for military, civil and space programs. During the last years several technical improvements have increased the lifetime of all Thales coolers resulting in significantly higher Mean Time To Failure (MTTF) figures. In this paper not only updated MTTF values for most of the products in our portfolio will be presented but also the methodology used to come to these reliability figures will be explained. The differences between rotary and linear coolers will be highlighted including the different failure modes influencing the lifetime under operational conditions. These updated reliability figures are based on extensive test results for both rotary and linear coolers as well as Weibull analysis, failure mode identifications, various types of lifetime testing and field results of operational coolers. The impact of the cooler selection for typical applications will be outlined. This updated reliability approach will enable an improved tradeoff for cooler selection in applications where MTTF and a correct reliability assessment is key. Improbing on cooler selection and an increased insight in cooler reliability will result in a higher uptime and operability of equipment, less risk on unexpected failures and lower costs of ownership.
Thales Cryogenics (TCBV) has an extensive background in delivering long-life cryogenic coolers for military, civil and
space programs. During the last years many technical improvements have increased the lifetime of coolers resulting in
significantly higher MTTF's. Lifetime endurance tests are used to validate these performance increases. An update will
be given on lifetime test of a selection of TCBV's coolers.
MTTF figures indicate the statistical average lifetimes for a large population of coolers. However, for the user of IR
camera's and spectrometers a detailed view on the performance of an individual cooler and the possible impact of its
performance degradation during its lifetime is very important. Thales Cryogenics is developing Cooler Diagnostic
Software (CDS), which can be implemented in the firmware of its DSP based cooler drive electronics. With this
implemented software the monitoring of the main cooler parameters during the lifetime in the equipment will be
possible, including the prediction of the expected cooler performance availability. Based on this software it will be
possible to analyze the status of the cooler inside the equipment and, supported by the lifetime knowledge at Thales
Cryogenics, make essential choices on the maintenance of equipment and the replacement of coolers.
In the paper, we will give an overview of potential situations in which such a predictive algorithm can be used. We will
present the required interaction with future users to make an optimal interaction and interpretation of the generated data
Thales Cryogenics (TCBV) has an extensive background in developing and delivering long-life cryogenic
coolers for military, civil and space programs. This cooler range is based on three main compressor concepts: rotary
compressors (RM), linear close tolerance contact seals (UP), and linear flexure bearing (LSF/LPT) compressors.
The main differences - next to the different conceptual designs - between these products are their masses and Mean
Time To Failure (MTTF) and the availability prediction of a single unit.
New developments at Thales Cryogenics enabling compact long lifetime coolers - with an MTTF up to 50.000
hrs - will be outlined. In addition new developments for miniature cooler drive electronics with high temperature
stability and power density will be described. These new cooler developments could be of particular interest for
space missions where lower costs and mass are identified as important selection criteria. The developed compressors
are originally connected to Stirling cold fingers that can directly be interfaced to different sizes of available dewars.
Next to linear coolers, Thales Cryogenics has compact rotary coolers in its product portfolio. Though having a
higher exported vibration level and a more limited MTTF of around 8.000 to 10.000 hours, their compactness and
high efficiency could provide a good alternative for compact cooling of sensors in specific space missions.
In this paper an overview of lifetime parameters will be listed versus the impact in the different cooler types.
Tests results from both the installed base and the Thales Cryogenics test lab will be presented as well. Next to this
differences in operational use for the different types of coolers as well as the outlook for further developments will
Thales Cryogenics (TCBV) has an extensive background in delivering long life cryogenic coolers for military, civil and
space programs. This cooler range is based on two main compressor concepts: close tolerance contact seals (UP) and
flexure bearing (LSF/LPT) coolers. Main difference between these products is the Mean Time To Failure (MTTF). In
this paper an overview of lifetime parameters will be listed versus the impact in the different cooler types. Also test
results from both the installed base and the Thales Cryogenics test lab will be presented.
New developments at Thales Cryogenics regarding compact long lifetime coolers will be outlined.
In addition new developments for miniature linear cooler drive electronics with high temperature stability and power
density will be described.
Thales Cryogenics has a long background in delivering cryogenic coolers with an MTTF far above 20.000 hrs for
military, civil and space programs. Developments in these markets required continuous update of the flexure bearing
cooler portfolio for new and emerging applications. The cooling requirements of new application have not only their
influence on the size of the compressor, cold finger and cooling technology used but also on the integration and control
of the cooler in the application.
Thales Cryogenics developed a compact Cooler Drive Electronics based on DSP technology that could be used for
driving linear flexure bearing coolers with extreme temperature stability and with additional diagnostics inside the CDE.
This CDE has a wide application and can be modified to specific customer requirements.
During the presentation the latest developments in flexure bearing cooler technology will be presented both for Stirling
and Pulse Tube coolers. Also the relation between the most important recent detector requirements and possible
available solutions on cryocooler level will be presented.
Thales Cryogenics is working with large effort on the extension and improvement of its full cryocooler product range for the military as well as the civil market. Due to improvements made in the last few years by most cooler manufacturers, cryocoolers are - in the defense world - more and more seen as a commodity. However, the requirements under which cryocoolers are used and the demands which users are requesting from a cryocooler such as increased reliability, shorter cooldown times, higher efficiency, lower induced vibrations and decrease in size and mass are still very challenging.
With as basis his wide product portfolio Thales Cryogenics has worked extensively on the extensions and improvement of its RM cooler range and to improve the CDT and robustness of its LSF cooler range for even more stringent environmental conditions. Next to the coolers also the latest control electronics of Thales for its linear drive coolers will be presented.
Apart from Stirling coolers Thales Cryogenics is also manufacturing pulse tube coolers. At present these coolers are mainly used in civil applications. Although the CDT and efficiency of pulse tube coolers are still lower compared to Stirling coolers the reduced vibration level and increased robustness of the cold finger could be beneficial for future developments with respect to sensor cooling.
This paper presents the latest results of the work performed at Thales and explains the gain for the users of cryocoolers.
Thales Cryogenics has presented the LSF 9599 SADA II flexure cooler in 2005. Based on Thales' well-known moving magnet flexure technology, the LSF 9599 complies with the SADA II specification with respect to performance, envelope and mass. Being the first manufacturer offering a full flexure-bearing supported cooler that fits within the SADA II envelope, Thales Cryogenics has been selected in several new (military) programs with their LSF coolers. For many of these new programs, the cooldown time requirements are more stringent than in the past, whereas at the same time size, complexity and thus thermal mass of the infrared sensor tends to increase. In order to respond to the need created by the combination of these trends, Thales Cryogenics started a development program to optimize cryogenic performance of the LSF 9599 cooler. The main goal for the development program is to reduce the cooldown time, while maintaining the SADA II compatible interface, and maintaining the robustness and proven reliability of the cooler.
Within these constraints, the regenerator was further optimized using among others the experience with mixed-gauze regenerators obtained from our pulse tube research. Using the mixed gauze approach, the heat storage capacity of the regenerator is adapted as a function of the temperature profile over the regenerator, thus giving the optimum balance between heat storage capacity and pressure drop. A novel way of constructing the regenerator further decreases shuttle heat losses and other thermal losses in the regenerator.
This paper describes the first results of the trade-offs and gives an overview of impact on cooldown times and efficiency figures achieved after the regenerator and displacer optimization.