Acoustic screen
US5764059A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1995 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Dec 1, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4215
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention describes apparatus for, and a method of, active acoustic screening and combined active acoustic and magnetic screening, of magnetic field coils, which pass a time varying current and which reside in relatively high static magnetic fields, typically greater than about 0.1 T. The invention is particularly well suited for acoustic screening of magnetic field gradient coils used in Magnetic Resonance Imaging (MRI). In a preferred embodiment a closed loop carrying current is arranged such that two different parts of the loop are mechanically coupled, dimensioned and arranged with respect to one another such that Lorentz forces experienced by the magnetic equipment are substantially reduced and preferably cancelled. In a different embodiment the invention is modified so as to permit simultaneous magnetic and acoustic screening. The invention overcomes existing problems of non-acoustically screened coils used in conjunction with high magnetic fields, by by reducing vibrational forces by cancelling them, within the gradient coil structure, rather than damping or absorbing emitted high levels of acoustic noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.