Series Piston Load Compensator for Nuclear Fuel Handling

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Solution Overview

Problem

Existing load compensating systems for nuclear reactor fuel element handling machines are not easily manufacturable, operable, efficient, or reliable, particularly in managing variations in the mass of the pickup device and the forces exerted on fuel elements.

Innovation Solution

A load compensating device featuring two fluid-operated piston devices connected in series, a slide, and an operating fluid feed circuit that maintains minimum and maximum tension in a hoisting cable to prevent excessive compression and pull on fuel elements, incorporating a safety lock system and microswitches to manage these forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing load compensating systems are used, then load compensation is provided, but the systems are difficult to manufacture and operate with reduced efficiency and reliability

Engineering Contradiction:
Improveload compensation reliabilityVSAvoidsystem manufacturability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The load compensating system is divided into two independent piston devices (first piston device 18a and second piston device 18b) connected in series, each handling different aspects of load compensation. This segmentation allows each piston device to be manufactured and maintained independently, improving ease of manufacture while maintaining reliable load compensation through distributed functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an operating fluid feed circuit 19 as an intermediary system that parallel-feeds fluid to both piston devices, and a safety lock system 39 as a mediator that intervenes when the fluid supply fails. These intermediary components enhance reliability by providing controlled fluid distribution and fail-safe mechanisms without complicating the core piston devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If existing load compensating systems are used, then load compensation is provided, but the systems are difficult to operate with reduced efficiency

Engineering Contradiction:
Improveload compensation efficiencyVSAvoidsystem operability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The piston devices are designed to automatically respond to load variations without requiring manual intervention. The first piston device 18a automatically compensates for the weight of the pickup device, while the second piston device 18b automatically compensates for variations in pickup device mass, enabling the system to self-regulate and improving both efficiency and ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The safety lock system 39 provides a feedback mechanism that monitors the operation of the piston devices and intervenes when abnormal conditions are detected (such as fluid supply failure). This feedback loop ensures efficient operation by preventing malfunction and automatically engaging safety protocols when needed.

Inventive Principle:
Principle #23Feedback

3Reliability

If single piston device is used, then simpler structure is achieved, but insufficient load compensation is provided for varying masses

Engineering Contradiction:
Improveload compensation reliabilityVSAvoidpiston device configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load compensating device is segmented into two piston devices 18a and 18b connected in series, with the first piston device handling constant weight compensation and the second piston device handling variable mass compensation. This segmentation provides reliable load compensation for varying masses while keeping each individual piston device relatively simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two piston devices work together to provide multiple functions: the first piston device 18a provides baseline load compensation, while the second piston device 18b adjusts for mass variations. This multi-functional arrangement achieves reliable load compensation across different operating conditions without requiring an overly complex single-device solution.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If mechanical series connection of piston devices is used, then load compensation is improved, but device complexity increases

Engineering Contradiction:
Improveload compensation performanceVSAvoidpiston connection structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The piston devices are connected in series through a straightforward mechanical arrangement where the first piston device 18a and second piston device 18b are positioned one after another along the vertical axis. This segmented series connection improves load compensation performance by distributing compensation functions while maintaining a relatively simple mechanical structure compared to parallel or complex interconnected configurations.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2479761B1Load compensating device for a nuclear fuel element handling machine
Publication Date: 2015.04.22 ANSALDO NUCLEARE
  • EP2479761B1 patent drawingFigure 1
  • EP2479761B1 patent drawingFigure 2
  • EP2479761B1 patent drawingFigure 3

AI summary

A load compensating device (15) for a nuclear fuel element handling machine has : a frame (16) fitted to a fixed supporting structure (13); a slide (17), which runs along the frame (16) and is attached to a hoisting member (6) such as a cable; a first and second fluid-operated piston device (18a, 18b) connected mechanically in series to each other and to the slide (17); and an operating fluid feed circuit (19) for parallel-feeding operating fluid to the piston devices (18). The first piston device (18a) is designed to keep the tension of the hoisting member (6) above a given minimum value (Tmin); and the second piston device (18b) is designed to keep the maximum tension of the hoisting member (6) below a given maximum value (Tmax).