Creative cryogenic systems
Cryogenic pumps
CryoZone offers a wide range of cryogenic pumps specially designed to achieve heat transfer between an application and a cooler using a flow of liquid. As direct conduction cooling between an application and a cooler is not possible in every kind of system, CryoZone has developed a different way to tackle this problem. After assessing an application’s requirements relating to cooling power, temperature and temperature homogeneity, we determine the optimal combination of flow and pressure drop. On the basis of this data the right cryogenic pump for the job is either chosen from our extensive range of existing designs, or custom-made to suit the job.
Specifications
Our cryofgenic pumps are centrifugal pumps that provide a liquid flow (usually helium or nitrogen) that thermally connects the application to a cryocooler.
This cold source can therefore be installed at an adequate distance and position from the application. Heat losses of the application are transferred to the cryocooler by the circulating liquid.
Like all centrifugal pumps, the main parts are the impeller and volute. Their dimensional shape determines the functionality and efficiency of the fan. The impeller is driven by a high rpm electric motor to create the flow. All components are placed within a single housing with the motor installed within the pressurized gas volume. This solution avoids the use of a rotating seal and hence the risk of leakage.
In order to create a thermal barrier between the motor at ambient temperature and the cold impeller, this is mounted on a long thin stainless steel shaft. This cantilever set-up with high-precision balanced shaft and impeller is used to avoid the necessity of a cold bearing. This set-up ensures a MTBM of over 36.000 hours.
The pressure housing with pump volute is mounted onto the cryostat and the liquid circuit lines are connected. The motor with shaft and impeller can now be mounted from the outside. This means that the complete impeller unit can be removed without breaking the vacuum.
