Tube Sheet Drilling Support With Play Compensation and Rigid Clamping
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Solution Overview
Problem
Existing drilling instruments for machining tubes in nuclear power plant heat exchangers face challenges in reaching multiple working positions efficiently, maintaining low mass, and achieving sufficient accuracy in radioactive environments, with existing robots either being too cumbersome or inaccurate for precise machining.
Innovation Solution
A drilling instrument with a transport device featuring clamping elements and a support system that allows for precise positioning and movement over a tube sheet, compensating for inaccuracies through play between components, enabling the drilling device to be securely clamped in place without transmitting forces to the transport device, and allowing for incremental movement and directional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robot arm is used to position the drilling machine, then the drilling machine can reach multiple working positions, but the mass of the robot becomes correspondingly high and the construction becomes particularly complicated
Solution Approach 1:
The system is divided into two independent parts: a transport device for moving the drilling device to various positions, and a drilling device for machining. The transport device uses a simple platform with retaining devices that can be alternately anchored in tubes, while the drilling device is rigidly connected during machining. This segmentation allows each component to be optimized independently, reducing overall complexity.
Solution Approach 2:
The transport device is designed to be movable and reconfigurable, allowing it to transport the drilling device to different positions on the tube sheet. The retaining devices can be alternately anchored and released to enable movement. During machining, the connection becomes rigid to ensure precision. This dynamic transition between movable and fixed states resolves the contradiction between versatility and complexity.
2Area of stationary object
If the robot arm is constructed to be so large that the working range corresponds to the extent of the tube sheet, then the working range is sufficient, but the mass of the repair robot is even greater and the construction or dismantling is particularly complicated
Solution Approach 1:
Instead of extending the robot arm in one dimension to cover the entire tube sheet area, the transport device moves along the surface of the tube sheet by anchoring and moving between tubes. This approach uses the two-dimensional surface of the tube sheet as the workspace, allowing coverage of large areas without requiring a large single-dimensional arm structure, thereby reducing mass.
3Weight of moving object
If an inspection robot with movable parts is used to move over the tube sheet, then the robot is lighter, but the mechanics exhibit a comparatively high level of inaccuracy in positioning which is not suitable for machining
Solution Approach 1:
The system transitions from a dynamically movable state during transport to a statically rigid state during machining. The drilling device is rigidly connected to the transport device when positioned, eliminating positioning errors. The movable parts are used only for transport, not for positioning during machining, thus achieving both low mass and high precision.
Solution Approach 2:
The transport device serves as an intermediary that carries the drilling device to the correct position, but does not perform the precise positioning itself. The drilling device, once delivered, performs the precise positioning and machining operations. This separation of functions allows the transport device to be lightweight while the machining device maintains high precision.
4Ease of operation
If a drilling machine mounted on a robot arm is used, then the drilling machine can be positioned at machining points, but the robot has to be moved to a different point for each machining location which is relatively complicated
Solution Approach 1:
The transport device is designed to pre-position the drilling device at multiple machining locations by alternately anchoring retaining devices in different tubes. This preliminary positioning action allows the drilling device to be quickly moved between points without requiring complex robot arm repositioning, thereby improving machining efficiency while maintaining ease of operation.
Data Source
AI summary
The present disclosure relates to a drilling instrument for machining tubes in tube sheets of heat exchangers in a radioactive environment, comprising a transport device having clamping elements and having a drilling device with clamping fingers, which are arranged in each case on a common first side. The transport device and the drilling device are connected to a support device having a support plate on which a resting plate of the drilling device rests. In addition, the support plate is connected to the resting plate by way of at least one movable connecting element, and the resting plate is connected to the support plate in a play-free manner in a first position of the connecting element, wherein the resting plate exhibits predefinable play with regard to the carrier plate in a second position of the connecting element.