US-12616403-B2 - Thermally insulated container and magnetospinograph using same

US12616403B2US 12616403 B2US12616403 B2US 12616403B2US-12616403-B2

Abstract

A thermally insulated container ( 10 ) includes an inner container ( 11 ), and an outer container ( 14 ) surrounding the inner container ( 11 ) via a void ( 15 ). Each of the inner container ( 11 ) and the outer container ( 14 ) contains a fiber reinforced plastic prepared by impregnating a base material with a resin. The inner container ( 11 ) includes a first tubular container ( 13 ) and a second tubular container ( 22 ) each having an internal holder ( 23, 24 ) to reserve a refrigerant ( 16 ), and a refrigerant inlet tube ( 12 ) through which the refrigerant ( 16 ) is introduced. The holder ( 24 ) is in communication with the holder ( 23 ). The base material in each of a predetermined area of the second tubular container ( 22 ) and a predetermined area of the outer container ( 14 ) contains woven fabrics. The predetermined area of the outer container ( 14 ) further includes a honeycomb sheet.

Inventors

Masaaki Hirai
Toshio Nakamura

Assignees

ARISAWA MFG. CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20220519
Priority Date: 20210528

Claims (18)

1 . A magnetospinograph, comprising: a superconducting quantum interference device to detect magnetic fields generated from a living body; and a thermally insulated container, comprising: an inner container; and an outer container surrounding the inner container via a void, wherein each of the inner container and the outer container is made of a fiber reinforced plastic prepared by impregnating a base material containing fibers with a resin, the inner container includes: a first tubular container and a second tubular container each including an internal holder to reserve a refrigerant, and a refrigerant inlet tube through which the refrigerant is introduced into the first tubular container, the outer container includes a first portion surrounding the first tubular container of the inner container and a second portion surrounding the second tubular container of the inner container, wherein the second portion of the outer container includes a predetermined area configured to receive a load of a measurement target, the holder of the second tubular container is in communication with the holder of the first tubular container, the base material in each of a predetermined area of the second tubular container and predetermined area of the second portion of the outer container contains woven fabrics, the base material in the predetermined area of the second portion of the outer container further contains a honeycomb sheet, the predetermined area of the second portion of the outer container having a higher rigidity from the honeycomb sheet than the areas of the outer container other than the predetermined area of the second portion of the outer container and the first portion of the outer container such that the predetermined area is configured to receive the load of the measurement target, and the woven fabrics are stacked on one and another surfaces of the honeycomb sheet, wherein, the superconducting quantum interference device is immersed in the refrigerant reserved in the holder of the second tubular container.
2 . The magnetospinograph according to claim 1 , wherein the woven fabrics contains at least one selected from the group consisting of glass fibers, alumina fibers, and carbon fibers.
3 . The magnetospinograph according to claim 1 , wherein the base material in the predetermined area of the outer container further contains a unidirectional fiber sheet fabricated by aligning multiple fibers to one direction, and the unidirectional fiber sheet is stacked on at least one of the one and the other surfaces of the honeycomb sheet.
4 . The magnetospinograph according to claim 3 , wherein a direction of the fibers of the unidirectional fiber sheet in the predetermined area of the outer container is parallel to a direction of extension of a central axis of the second tubular container.
5 . The magnetospinograph according to claim 3 , wherein the base material in the predetermined area of the second tubular container further contains a unidirectional fiber sheet fabricated by aligning multiple fibers to one direction.
6 . The magnetospinograph according to claim 5 , wherein a direction of the fibers of the unidirectional fiber sheet in the predetermined area of the second tubular container is orthogonal to a direction of extension of a central axis of the second tubular container.
7 . The magnetospinograph according to claim 5 , wherein the outer container surrounds the second tubular container such that the unidirectional fiber sheet in the predetermined area of the outer container is opposed to the unidirectional fiber sheet in the predetermined area of the second tubular container.
8 . The magnetospinograph according to claim 3 , wherein the unidirectional fiber sheet in the predetermined area of the outer container contains at least one selected from the group consisting of glass fibers, alumina fibers, and carbon fibers.
9 . The magnetospinograph according to claim 5 , wherein the unidirectional fiber sheet in the predetermined area of the second tubular container contains at least one selected from the group consisting of glass fibers, alumina fibers, and carbon fibers.
10 . The magnetospinograph according to claim 1 , wherein the honeycomb sheet has a thickness of 1 to 7 mm.
11 . The magnetospinograph according to claim 1 , wherein the resin contains an epoxy resin.
12 . The magnetospinograph according to claim 1 , wherein the honeycomb sheet includes hexagonal cells, wherein each side of the hexagonal cells has a length of 3 to 10 mm.
13 . The magnetospinograph according to claim 12 , wherein the length is 3 to 5 mm.
14 . The magnetospinograph according to claim 1 , wherein the fabric is stacked and attached on one surface and the other surface of the honeycomb sheet.
15 . The magnetospinograph according to claim 1 , and a measurement surface of the superconducting quantum interference device faces the predetermined area of the second tubular container and the predetermined area of the second portion of the outer container.
16 . The magnetospinograph according to claim 1 , wherein the second tubular container includes a portion having an axis disposed horizontally and a bottom surface portion closing one end portion of the cylindrical portion, and the second portion of the outer container extends laterally from the first portion of the outer container.
17 . The magnetospinograph according to claim 1 , wherein the first portion of the outer container has a longitudinal axis and the second portion of the outer container extends laterally from the first potion of the outer container.
18 . A thermally insulated container, comprising: an inner container; and an outer container surrounding the inner container via a void, wherein each of the inner container and the outer container is made of a fiber reinforced plastic prepared by impregnating a base material containing fibers with a resin, the inner container includes: a first tubular container and a second tubular container each including an internal holder to reserve a refrigerant, and a refrigerant inlet tube through which the refrigerant is introduced into the first tubular container, the outer container includes a first portion surrounding the first tubular container of the inner container and a second portion surrounding the second tubular container of the inner container, wherein the second portion of the outer container includes a predetermined area configured to receive a load of a measurement target, the holder of the second tubular container is in communication with the holder of the first tubular container, the base material in each of a predetermined area of the second tubular container and predetermined area of the second portion of the outer container contains woven fabrics, the base material in the predetermined area of the second portion of the outer container further contains a honeycomb sheet, the predetermined area of the second portion of the outer container having a higher rigidity from the honeycomb sheet than the areas of the outer container other than the predetermined area of the second portion of the outer container and the first portion of the outer container such that the predetermined area is configured to receive the load of the measurement target, and the woven fabrics are stacked on one and another surfaces of the honeycomb sheet; and a superconducting quantum interference device that detects a magnetic field generated from the measurement target, wherein the superconducting quantum interference device is immersed in the refrigerant stored in the accommodation portion of the second tubular container.

Description

TECHNICAL FIELD The present disclosure relates to a thermally insulated container and a magnetospinograph including the thermally insulated container. BACKGROUND ART In the medical field, a magnetospinograph, which is an apparatus for measuring magnetic fields generated in response to neural activities in a spinal cord, has been developed. Such a magnetospinograph measures weak magnetic fields generated in the spinal cord with a superconducting quantum interference device (hereinafter referred to as “SQUID”) based on the principle of superconducting property. In order to achieve a superconducting state, the SQUID is required to be immersed in a refrigerant, such as liquid helium. The magnetospinograph thus demands a thermally insulated container having excellent thermal insulation properties and capable of reserving the refrigerant for a long period. This thermally insulated container needs to contain non-magnetic materials unsusceptible to magnetic force. For example, Patent Literature 1 discloses an extremely low temperature container including an inner container made of a fiber reinforced plastic (hereinafter also referred to as “FRP”) and an outer container surrounding the inner container, and discloses a magnetic detecting apparatus including this extremely low temperature container. The inner container is filled with a liquid having a low boiling point. A magnetic detecting sensor is installed in this liquid. The void between the inner container and the outer container is in a vacuum state. CITATION LIST Patent Literature Patent Literature 1: Unexamined Japanese Patent Application Publication No. H7-302933 SUMMARY OF INVENTION Technical Problem Since the magnetospinograph measures weak magnetic fields, the distance (lift-off) between the SQUID and the measurement target site of a spinal cord must be made as short as possible. In particular, the thermally insulated container located between the SQUID and the measurement target site of the spinal cord is required to include walls having a reduced thickness, while maintaining sufficient thermal insulation performance. The inner container and the outer container disclosed in Patent Literature 1 include thick walls in order to improve the thermal insulation performance. Unfortunately, these thick walls inhibit the SQUID from detecting weak magnetic fields. An objective of the present disclosure, which has been accomplished in view of the above situations, is to provide a thermally insulated container characterized by excellent thermal insulation properties and thin walls, and a magnetospinograph including the thermally insulated container. Solution to Problem In order to achieve the above objective, [1] a thermally insulated container according to a first aspect of the present disclosure includes an inner container and an outer container surrounding the inner container via a void. Each of the inner container and the outer container is made of a fiber reinforced plastic prepared by impregnating a base material including fibers with a resin. The inner container includes a first tubular container and a second tubular container each having an internal holder to reserve a refrigerant, and a refrigerant inlet tube through which the refrigerant is introduced into the first tubular container. The holder of the second tubular container is in communication with the holder of the first tubular container. The base material in each of a predetermined area of the second tubular container and a predetermined area of the outer container contains woven fabrics. The predetermined area of the outer container further contains a honeycomb sheet. The woven fabrics are stacked on one and the other surfaces of the honeycomb sheet. [2] The woven fabrics may contain at least one selected from the group consisting of glass fibers, alumina fibers, and carbon fibers. [3] The base material in the predetermined area of the outer container may further contain a unidirectional fiber sheet fabricated by aligning multiple fibers to one direction. The unidirectional fiber sheet may be stacked on at least one of the one and the other surfaces of the honeycomb sheet. [4] The direction of the fibers of the unidirectional fiber sheet in the predetermined area of the outer container may be parallel to the direction of extension of the central axis of the second tubular container. [5] The base material in the predetermined area of the second tubular container may further contain a unidirectional fiber sheet fabricated by aligning multiple fibers to one direction. [6] The direction of the fibers of the unidirectional fiber sheet in the predetermined area of the second tubular container may be orthogonal to the direction of extension of the central axis of the second tubular container. [7] The outer container may surround the second tubular container such that the unidirectional fiber sheet in the predetermined area of the outer container is opposed to the unidirectional fiber sheet in the predeterm