Multiplexed Heating Strips for Compact Plastic Bag Welding

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Solution Overview

Problem

Current welding technologies for plastic bags in the nuclear industry, such as high-frequency generators and resistance heater generators, are bulky, hazardous, and difficult to use in confined spaces, with high power requirements and old technology components, leading to reduced maneuverability and safety concerns.

Innovation Solution

A method and device for welding plastic bags using individually supplied heating strips with multiplexed electrical energy distribution, where each strip receives successive energy waves offset in time, with a PID-type regulator for temperature control and motorized clamping for ease of use, allowing for efficient and safe welding in restricted areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high-frequency generators are used for welding plastic bags, then welding power is sufficient, but equipment volume becomes very large and maneuverability is reduced

Engineering Contradiction:
Improvewelding powerVSAvoidequipment volume
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The welding device is divided into separate functional modules: a compact generator unit and a handheld welding gun. The heating element is integrated into the gun, which is separated from the power source. This segmentation allows the power generation part to be compact while the welding part remains maneuverable and easy to handle.

Inventive Principle:
Principle #1Segmentation

2Power

If high-frequency generators are used for welding plastic bags, then welding power is sufficient, but safety risks increase due to high voltages and currents

Engineering Contradiction:
Improvewelding powerVSAvoidsafety risks
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

By separating the high-power generation unit from the welding gun, the hazardous high-voltage components are confined to the generator housing, which operators do not directly handle. The welding gun contains only low-voltage, low-current heating elements, significantly reducing the risk of electric shocks and burns during operation.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If resistance heater generators are used for welding plastic bags, then safety is improved, but equipment volume remains large

Engineering Contradiction:
ImprovesafetyVSAvoidequipment volume
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The device separates the power source from the heating element. The generator unit contains the resistance heater components, while the welding gun contains only the compact heating strip and clamping mechanism. This allows the overall system to be safer while the handheld portion remains compact and maneuverable.

Inventive Principle:
Principle #1Segmentation

4Productivity

If heating strips are supplied with electricity simultaneously, then heating efficiency is high, but power requirements become excessive

Engineering Contradiction:
Improveheating efficiencyVSAvoidpower requirements
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The control device activates heating strips sequentially in periodic cycles rather than simultaneously. Each strip receives electrical power in alternating intervals, ensuring that at any given moment, only one or a few strips are active. This periodic activation maintains effective heating while significantly reducing the peak power draw from the generator.

Inventive Principle:
Principle #19Periodic action

5Power

If heating strips are supplied with electricity in succession with multiplexed energy distribution, then power requirements are reduced, but control complexity increases

Engineering Contradiction:
Improvepower requirementsVSAvoidcontrol complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The control device automatically manages the sequential activation and timing of multiple heating strips without requiring manual intervention. The system self-regulates the periodic cycles and energy distribution to each strip, simplifying operation while maintaining reduced power requirements. The complexity is contained within the automated control unit rather than requiring complex manual coordination.

Inventive Principle:
Principle #25Self-service

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

The solution provides a safer, more maneuverable, and reliable welding process with improved reproducibility and reduced equipment weight, enabling efficient sealing of plastic bags in challenging environments without the need for massive generators, ensuring operator safety and effective containment of toxic materials.

Implementation Method 1

each heating strip being supplied with electricity individually... send into each heating strip successive electrical energy waves

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2066490B1Welding device for plastic bags and method of heating its heating strips
Publication Date: 2010.04.28 AREVA NC
  • EP2066490B1 patent drawingFigure 1
  • EP2066490B1 patent drawingFigure 2~4

AI summary

The system according to the invention allows plastic bags to be very securely sealed by welding, using a compact apparatus. The device uses the multiplexing of the electrical energy sent into the heating strips of the welding tongs. Specifically, the strips are heated by successive waves following one after another in an offset and alternating manner, so that, at each instant, only one heating strip is supplied with power. Thus, the overall energy sent into the heating strips is relatively constant and of low level. Application to welding tongs for welding plastic bags used for handling contaminated materials in gloveboxes.