Patent ID: 9588198
Date: 2017-03-07
CPC Classifications: G01R

Claim:
1. An open type nuclear magnetic resonance magnet system having an iron ring member, the magnet system comprising: an upper portion and a lower portion; the upper and lower portions having the same structure and being symmetrical about an imaging central point of the magnet system; each of the upper and lower portions comprising an annular superconducting coil and a cryogenic container within which the superconducting coil is placed to be subjected to a cryogenic environment so as to achieve superconducting, wherein: the upper portion further includes an upper iron yoke associated with its superconducting coil, the lower portion also includes a lower iron yoke associated with its superconducting coil, and a lateral iron yoke is disposed between the upper and lower iron yokes, so that a magnetic flux circuit is formed for magnetic field generated by the superconducting coil in operation, through the upper and lower iron yokes and the lateral iron yoke and meanwhile the magnetic field is shielded; the upper and lower iron yokes and the lateral iron yoke being configured to be magnetized by the magnetic field generated by the superconducting coil, the superconducting coil generating a desired magnetic field in a magnet imaging central area; the system further includes a cylindrical iron ring mounted in a space defined by an inner perimeter wall of each cryogenic container, and an iron ring supporting member made from non-ferromagnetic materials and supporting the iron ring; the iron ring is configured to change a magnetic field distribution between the superconducting coil and the corresponding one of the upper and lower iron yokes to thus reduce or completely offset an electromagnetic interaction force between the superconducting coil and the corresponding one of the upper and lower iron yokes; each iron ring supporting member being connected to a respective one of the upper and lower iron yokes; the iron ring is comprised of cylindrical iron laminations; and an outer perimeter of the iron ring approaches to an inner side perimeter wall of the cryogenic container.