Simple construction of strong magnets reinforced by ice and woven glass cloths for long high pulsed field

Takeyama, S.; Sasaki, Susumu; Ochimizu, Hideaki; Miura, N.

doi:10.1109/20.119918

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…Motokawa et al [84], does this by encasing the coil in a stainless steel shell, which is then packed with alumina filler, evacuated, filled with water, and slowly cooled using liquid nitrogen. Similar processes are described in [79,82,83,85]. The impregnation is made easy by the fact that there is no need to worry about usable life and the viscosity of water is less than 1/10 of typical epoxy [86].…”

Section: Water Icementioning

confidence: 93%

“…Water ice has been proven a feasible impregnation method in numerous studies. Takeyama et al [82,83] reported success in many operations of a 55 T pulsed magnet impregnated in ice with woven-glass cloths, including melting the ice and refreezing it. Motokawa et al [84] compared a magnet impregnated with ice with an identical one impregnated with epoxy and found that the ice-impregnated magnet was able to produce higher fields.…”

Section: Water Icementioning

confidence: 99%

“…One common observation, shared by [79,[82][83][84] is that ice impregnation is uniquely easy and economical. Motokawa et al [84], does this by encasing the coil in a stainless steel shell, which is then packed with alumina filler, evacuated, filled with water, and slowly cooled using liquid nitrogen.…”

Section: Water Icementioning

confidence: 99%

“…Data from the literature shows that the thermal conductivity of ice at cryogenic temperatures is around 10-20 W mK −1 [87], which is orders of magnitude higher than epoxy or wax. Takeyama et al [82] reported that the ice-impregnated magnet was able to cool to LN 2 temperatures in less than 40% of the time it would take for an epoxy-impregnated magnet. Similarly, Wang et al [79] and Ding et al [88] found that ice had better cooling performance than epoxy impregnation.…”

Section: Water Icementioning

confidence: 99%

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Review of materials for HTS magnet impregnation

Feldman,

Stautner,

Kovacs

et al. 2024

Supercond. Sci. Technol.

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Construction of high-temperature superconducting magnets typically involves impregnation of a coil in a liquid medium, such as epoxy, which is then solidified. This impregnation provides mechanical integrity to the magnet and facilitates heat transfer. The choice of material used for impregnation requires careful consideration of the material properties and the performance requirements in order to ensure optimal magnet operation. This paper offers a comprehensive educational resource on this topic, reviewing the literature available on materials for magnet impregnation. A detailed explanation of considerations for selecting an impregnation material are presented, along with a review of several types of materials and their characteristics as reported in the literature. The materials are compared, and their suitability to different applications is discussed. Topics for future research are suggested.

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Section: Water Icementioning

confidence: 93%

Section: Water Icementioning

confidence: 99%

Section: Water Icementioning

confidence: 99%

Section: Water Icementioning

confidence: 99%

See 2 more Smart Citations

Review of materials for HTS magnet impregnation

Feldman,

Stautner,

Kovacs

et al. 2024

Supercond. Sci. Technol.

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“…In view of this, we proposed the ice impregnation technique to solve the shortcomings of the previous methods. Ice impregnation was first applied to pulsed magnets by Motokawa et al in 1989 [29][30][31][32][33]. It was found that pulsed magnets impregnated with ice produced up to 62 T without noticeable damage, which means that the mechanical strength of the ice impregnated coils was relatively high.…”

Section: Introductionmentioning

confidence: 99%

A new method for avoiding critical current degradation of YBCO coils using ice impregnation

Wang

Ding

et al. 2019

Supercond. Sci. Technol.

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For mechanical reinforcement against the huge Lorentz forces in high magnetic fields, epoxy resins are commonly used to impregnate high temperature superconductor (HTS) coils. Due to the different thermal expansion coefficients between the epoxy resin and the HTS tape, the contraction of the epoxy resin causes critical current degradation in the HTS coils during the cooling process. Alternative techniques, such as coils with no insulation, can avoid current degradation, however their structure has no reinforcement between layers. In view of this, we tried to apply the ice impregnation technique of pulsed magnets to HTS coils for the first time. HTS coils impregnated with ice could avoid critical current degradation after thermal cycles. Also, local heat pulse tests and overcurrent tests showed that the ice impregnated coil had better thermal stability than the epoxy impregnated coil. Moreover, the fabrication process of the ice impregnated coil is simple and economical. Meanwhile HTS tapes can be reused after impregnation. The ice impregnation technique is a promising prospect for high temperature superconducting coils.

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