Cryogenic Actuation Push-Rod with Thermal Radiation Shield

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Solution Overview

Problem

Conventional actuation methods in cryogenic environments, such as superconducting magnet systems, introduce excessive thermal conduction, which can disrupt the cryogenic conditions.

Innovation Solution

A mechanical actuation system is implemented using a push-rod mechanism with a thermal radiation shield to minimize thermal conduction, where the push-rods are constructed of low thermal conductivity materials and thermally linked to the shield, allowing actuation without significant heat transfer from room temperature to the cryogenic environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional actuation methods (electrical drives, gas pressure, pistons) are used to apply actuation force to devices in cryogenic environment, then the actuation function is achieved, but excessive thermal conduction is introduced which disrupts the cryogenic conditions

Engineering Contradiction:
Improveactuation forceVSAvoidcryogenic temperature stability
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

A push-rod mechanism serves as an intermediary mechanical linkage between the room-temperature actuator and the cryogenic device. The push-rod transmits actuation force while being thermally isolated through a thermal radiation shield, preventing direct thermal conduction between the actuator and the cryogenic environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The actuator is extracted from the cryogenic environment and placed in the room-temperature outer vacuum container. Only the push-rod penetrates into the cryogenic region, and even then, thermal conduction is minimized through the radiation shield, effectively separating the thermal environments while maintaining mechanical connectivity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If mechanical actuation is applied through access ports (neck tube) to devices in cryogenic environment, then actuation is achieved, but thermal conduction through the access port compromises the thermal isolation

Engineering Contradiction:
Improveactuation accessibilityVSAvoidthermal isolation
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The thermal radiation shield acts as an intermediary barrier between the access port and the cryogenic device. It intercepts thermal radiation and reduces conductive heat transfer along the push-rod, maintaining thermal isolation while allowing mechanical actuation to proceed through the same access path.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The push-rod exhibits different thermal properties at different locations: it is thermally isolated at the cryogenic end by the radiation shield while being connected to the room-temperature actuator. This local differentiation of thermal conductivity allows mechanical force transmission without compromising overall thermal isolation.

Inventive Principle:
Principle #3Local quality

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 solution enables effective actuation of devices in cryogenic environments while maintaining low thermal conduction, ensuring the cryogenic conditions are not compromised, allowing for reliable operation and simplified servicing.

Implementation Method 1

a thermal radiation shield placed within the OVC, shielding the cryogen cooled component from radiant heat from the OVC

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

push-rods are constructed of low thermal conductivity materials and thermally linked to the shield, allowing actuation without significant heat transfer from room temperature to the cryogenic environment

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9966172B2Actuation arrangement
Publication Date: 2018.05.08 SIEMENS HEALTHCARE LTD

AI summary

A mechanical actuation arrangement for remotely applying a force to a cryogenically-cooled device has a mechanical actuator composed of multiple parts. In use, the parts bear against one another to enable a force to be applied to the device by an actuator device, and when not in use, the parts separate.