Compact Melter with Subdivided Channels for Rapid Hot Melt Adhesive Processing

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Solution Overview

Problem

Conventional hot melt dispensing systems require extensive heating throughout the tank, pump, and tubing to maintain adhesive in a liquid state, leading to prolonged start-up times and increased risk of adhesive charring due to prolonged heat exposure, as well as inefficient melting of pellets in large volume tanks.

Innovation Solution

A compact hot melt dispensing system with a small melter unit using resistive heating elements and a high surface-area-to-volume ratio design, where solid adhesive pellets are melted quickly and efficiently, allowing for rapid start-up and minimizing heat exposure, featuring a cylindrical melter with subdivided channels for enhanced heat exchange and a separate cold section for pellet storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a large volume tank is used to store pellets for extended dispensing periods, then the dispensing duration is extended, but the start-up time increases and adhesive charring risk increases

Engineering Contradiction:
Improvedispensing durationVSAvoidstart-up time
Core Design Contradiction:
Duration of action of moving objectVSLoss of time

Solution Approach 1:

The system divides the pellet storage and melting function into two separate sections: a large cold storage section for holding pellets and a small melter section for actual melting. This segmentation allows the storage capacity to remain large while the melting volume remains small, resolving the contradiction between extended dispensing duration and reduced start-up time.

Inventive Principle:
Principle #1Segmentation

2Reliability

If heating elements are placed throughout the tank, pump, and dispenser to maintain adhesive temperature, then the adhesive remains in liquid state, but energy consumption increases and adhesive charring risk increases

Engineering Contradiction:
Improveadhesive liquid state maintenanceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system extracts the heating function from the entire adhesive pathway and concentrates it only in the small melter section. The cold storage section remains unheated, and only the melter and immediate dispensing path require heating. This reduces the total volume requiring thermal maintenance, thereby reducing energy consumption and charring risk while maintaining reliable liquid state delivery.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If multiple heating elements line the walls of a rectangular tank, then heating coverage is improved, but heat distribution efficiency decreases and start-up time increases

Engineering Contradiction:
Improveheating coverageVSAvoidmelting efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The system segments the melting function into a small dedicated melter with controlled heating, separate from the large storage tank. This allows concentrated heating power in a small volume, achieving rapid and efficient melting without the heat distribution problems of large tanks. The small melter can be heated uniformly and quickly, improving productivity while maintaining adequate temperature coverage.

Inventive Principle:
Principle #1Segmentation

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 system achieves rapid melting and dispensing of hot melt adhesive, reducing start-up times to approximately ten minutes and minimizing adhesive charring, while maintaining the adhesive in a liquid state throughout the dispensing process.

Implementation Method 1

A compact hot melt dispensing system with a small melter unit using resistive heating elements

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

a cylindrical melter with subdivided channels for enhanced heat exchange

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a cylindrical melter with subdivided channels for enhanced heat exchange

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the melted pellets must be maintained at temperature from the tank to the dispenser

Methodology Applied
Scientific EffectThermal equilibrium: Heating

Data Source

PatentEP3597309B1melter
Publication Date: 2022.03.23 GRACO MINNESTOA INC
  • EP3597309B1 patent drawingFigure 1
  • EP3597309B1 patent drawingFigure 2A
  • EP3597309B1 patent drawingFigure 2B

AI summary

A melt system capable of heating hot melt pellets into a liquid includes a melter (48) including a body, a chamber (90), a collector (100), channels (94), a heater (50) and a feed cap (54) comprising a sensor tower (56) and a level sensor (58) connected to the sensor tower. The thermally conductive body forms an interior with a surface area. The chamber is at an upper end of the body for receiving the pellets. The collector is within the body and located below the chamber for receiving the liquid from the melted pellets. The channels extend between the chamber and the collector to increase the surface area of the interior. The heater transfers heat to the body, and the walls of the channels form heat exchange surfaces. The level sensor senses a level of adhesive pellets in the melter.