GRE were contracted to design and manufacture a custom cryostat for NPL (National Physical Laboratory), which comprised a cooled (with a Sumitomo cryocooler), vacuum insulated, cryostat vessel with removable sample holder and temperature control via a microprocessor and touch screen HMI. The system also required the ability to communicate with the client’s LabView system.
System details
The proposed system used a Sumitomo CH110 cryocooler head, mounted directly onto the cryostat vessel. The cryocooler head then cooled the surface of a GRE-designed heat exchanger, by conduction and the use of electric heaters to ‘trim’ the temperature. The heat exchanger surface then transferred the cooling effect to the (interchangeable) media test cartridge, which was fitted with two calibrated, low temperature thermocouples. Secondary cooling for the gas stream into the sample holder was also provided by a vacuum-brazed tube coiled around the upper part of the heat exchanger.
System performance
Cooling power : 22oW @ 115K
GRE’s full scope of works for this ‘turnkey’ project comprised the following:
- Sumitomo CH 110 cryocooler plus the matching water cooled compressor, helium charge and transfer lines.
- Cryostat Vessel (designed to accept interchangeable sample holder)
- Internal (to cryostat) active heat exchanger system with (copper) thermal shield, between the sample holder/primary circuit and the CH 110 cryocooler cold head.
- All electronics, controls, software and communications link to external monitoring software.
System concept, design, analysis, manufacture and testing undertaken by GRE; Sumitomo cryocooler supplied by gasandliquidcontrols.com, all bespoke machined components, including heat exchanger, flanges and fittings, supplied by ashbrook-engineering.co.uk
