Gradient Coil Cooling Channel External Placement

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Solution Overview

Problem

Existing gradient coil assemblies in MRI systems face challenges with high eddy currents and inefficient cooling, leading to increased heating and reduced cooling efficiency, especially in wide-bore systems.

Innovation Solution

The cooling channel is arranged outside and along the conductor lines of the gradient coil, with a U-shape or C-shape open at one side, allowing direct contact between the cooling fluid and the conductor lines, thereby enhancing cooling efficiency and reducing eddy currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the cooling channel is placed inside the gradient coil, then the cooling fluid can be in close proximity to the conductor lines, but this arrangement generates high eddy currents and reduces cooling efficiency

Engineering Contradiction:
Improvecooling efficiencyVSAvoideddy current losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent inverts the conventional cooling channel placement by moving it from the interior to the exterior of the gradient coil. The cooling channel is positioned in thermal contact with the outer surface of the gradient coil, allowing cooling fluid to flow outside the coil structure. This inversion eliminates eddy currents in the cooling channel while maintaining effective heat removal through the coil's outer surface.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the cooling channel is arranged with a wall separating it from conductor lines, then the cooling fluid is isolated from the conductors, but this reduces cooling efficiency

Engineering Contradiction:
Improveelectrical isolationVSAvoidcooling efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent extracts the cooling channel from the interior space of the gradient coil and positions it externally. The cooling channel is formed in the support structure surrounding the gradient coil, allowing the cooling fluid to flow in direct thermal contact with the coil's outer surface without requiring an internal wall separation. This extraction achieves both electrical isolation and efficient cooling.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the gradient coil design is optimized for wide-bore systems, then the imaging capability is improved, but the gradient coil radius increases leading to higher power requirements and more difficult cooling

Engineering Contradiction:
Improvewide-bore system capabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The patent transitions the cooling approach from an internal three-dimensional arrangement to an external surface-based cooling system. By positioning the cooling channel on the outer surface of the gradient coil and utilizing the coil's cylindrical geometry, the system achieves effective heat removal without increasing the coil's internal complexity or power consumption, even for wide-bore applications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration minimizes eddy current losses, maintains efficient cooling, and allows for a compact design, effectively addressing the heating issues in gradient coil assemblies.

Implementation Method 1

the cooling channel is arranged outside and along the conductor lines of the gradient coil, with a U-shape or C-shape open at one side, allowing direct contact between the cooling fluid and the conductor lines

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cooling fluid flowing in the cooling channel gets into direct contact with a part of the surface of the one or more conductor lines

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

This heating is mainly caused by eddy currents and resistive heating as current is passed through the gradient coil

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 4

This heating is mainly caused by eddy currents and resistive heating as current is passed through the gradient coil

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Data Source

PatentEP3622308B1Cooling a gradient coil of a magnetic resonance imaging system
Publication Date: 2025.01.15 KONINKLIJKE PHILIPS NV
  • EP3622308B1 patent drawingFigure 1~2
  • EP3622308B1 patent drawingFigure 3~4

AI summary

The present invention is related to cooling a gradient coil (2) of a magnetic resonance imaging system (1). According to the invention, a gradient coil assembly for a magnetic resonance imaging system (1) is provided, the gradient coil assembly comprising at least one gradient coil (2) and a cooling arangement for cooling the gradient coil (2), wherein the gradient coil (2) is comprised of a solid electrical conductor material forming one conductor line (21) or more conductor lines (21, 31, 41) which are in direct contact with each other, the cooling arangement comprises a cooling channel (22, 32, 42) for guiding a cooling fluid (10), and the cooling channel (22, 32, 42) is arranged outside along the one or more conductor lines (21, 31, 41) in such a way that in a cross-sectional view one single continuous interface line between the cooling channel (22, 32, 42) and the one or more conductor (21, 31, 41) lines is formed. In this way efficient cooling of the gradient coil (2) may be achieved.