Cold Head Disassembly Using a Lifting Jig in Tight Maintenance Space
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Solution Overview
Problem
The maintenance of large cold heads in cryocoolers is challenging due to their weight and limited space around them, making it difficult to decompose and reassemble, especially when there is no sufficient space for proper access and handling of heavy components.
Innovation Solution
A method involving the use of lifting-up and displacer holding jigs to facilitate the decomposition of the cold head, where a lifting-up jig is mounted onto the displacer drive unit to lift the displacer drive unit and displacer together, and a displacer holding jig is used to securely hold the displacer during extraction, allowing for easier detachment and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the cold head is decomposed for maintenance, then the maintenance can be performed without increasing the temperature of the object to be cooled, but the weight and limited space make it difficult to perform the decomposition and assembly operations
Solution Approach 1:
A lifting-up jig is introduced as an intermediary tool to facilitate the decomposition and assembly operations. The jig includes a lifting-up portion that engages with the displacer drive unit and a support portion that rests on the cylinder, providing mechanical advantage and control during the separation and reassembly of the cold head components, thereby making operations feasible in constrained spaces with heavy components
2Ease of repair
If the cold head is decomposed for maintenance, then the maintenance can be performed without increasing the temperature of the object to be cooled, but the large weight of components makes the operation difficult
Solution Approach 1:
The lifting-up jig acts as a mechanical intermediary that distributes and manages the weight of heavy components during manipulation. By providing a structured lifting mechanism with engagement portions and support structures, the jig enables operators to control and move heavy displacer drive units and other components without direct manual handling, thus overcoming the difficulty posed by component weight
Data Source
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AI summary
To improve a workability for maintenance of a cold head (22). Provided is a method of decomposing the cold head (22) . The cold head (22) is provided with a displacer (40) that extends in an axial direction, a cylinder (36) that accommodates the displacer (40), and a displacer drive unit (42) that is fastened to the cylinder (36) and is connected to the displacer (40) such that the displacer (40) is driven in the axial direction. The method includes mounting a lifting-up jig (70) onto the displacer drive unit (42), unfastening the displacer drive unit (42) and the cylinder (36) from each other, and operating the lifting-up jig (70) such that the displacer drive unit (42) is lifted up from the cylinder (36) together with the displacer (40).