Cryogen Free Systems from Cryomagnetics Inc.
The elimination of liquid cryogens and thus the reservoirs to contain them has meant that the cryogen free alternative is a fraction of the size and weight of the conventional systems. The development of these systems has opened up new markets in places where liquid helium is difficult or impossible to obtain. The Cryogen free systems offered are based on two different cryocoolers, the 4.2K pulse tube (PT) and the 4.2K Gifford McMahon (GM).
HSL offers a full range of high quality cryogen free systems including superconducting magnet systems that are cooled to 4.2K using Pulse tube or Gifford McMahon cryocoolers.
Pulse tube refrigerators are thermodynamically less efficient than the GM refrigerators but since they have no moving cold parts the vibration due to the coldhead is minimised. Elimination of a displacer in the cold head simplifies the construction and increases the reliability. The only maintenance required on these systems is replacement of the absorber in the compressor every 30,000 hours of continuous operation. However the pulse tube coolers can only be operated in a vertical orientation.
The 4.2K GM based systems are thermodynamically more efficient and have the added flexibility of being able to operate in any orientation. A popular configuration involves the mounting of a magnet on a stand and rotating the room temperature bore, allowing access in either horizontal or vertical positions.
The disadvantage of these coolers is the added vibration due to the moving displacer within the coldhead. This leads to a maintenance requirement of seal replacement every 10,000 to 15,000 hours and an absorber change every 20,000 to 30,000 hours of continuous operation.
For assistance with your cryogen free systems specification and purchase please call Hall Scientific Ltd on Tel +44 203 004 9895. Alternatively out of hours please leave a message via our Contact us page and we will be pleased to respond to you as quickly as possible.