High-Pressure Adhesive Nozzle with Protective Dried Air Chamber
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Solution Overview
Problem
Existing devices for applying moisture-curing adhesives face challenges such as high design effort, leaks, premature curing, and inefficient application, especially when handling one-component PUR adhesives, which harden upon exposure to moisture, leading to clogging and increased maintenance needs.
Innovation Solution
A device with multiple nozzle openings and switchable adhesive feeds uses a dried air stream as a protective medium to prevent premature curing, allowing for high-pressure operation above 30 bar and maintaining nozzle integrity, enabling adaptive application to various workpiece sizes with reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane valves are used to dispense moisture-curing adhesives, then the barrier between adhesive and air is improved, but the pressure tolerance is limited to below 20 bar and service life is short
Solution Approach 1:
The patent changes the pressure parameter by introducing a protective medium pressure system that maintains pressures above 30 bar in the adhesive supply line, specifically designed to work with high-pressure needle valves rather than membrane valves, thereby resolving the pressure tolerance limitation
Solution Approach 2:
The patent introduces a protective medium (dried air stream) as an intermediary substance that prevents moisture-curing adhesive from contacting ambient moisture. This mediator allows the use of high-pressure needle valves while maintaining the protective barrier function, enabling both high pressure operation and reliable adhesive protection
2Quantity of substance
If individual nozzles are switched off to match workpiece dimensions, then adhesive consumption is reduced, but premature curing occurs in active nozzles leading to clogging
Solution Approach 1:
The patent creates an inert atmosphere by introducing a protective medium (dried air) into the protective space surrounding active nozzles. This inert environment prevents premature moisture-curing of adhesive in nozzles that remain open during selective application, eliminating clogging while allowing adaptive nozzle activation based on workpiece dimensions
3Speed
If high-pressure operation above 30 bar is implemented, then jet velocity and application precision are improved, but seal wear and maintenance requirements increase
Solution Approach 1:
The protective medium acts as a mediator that prevents adhesive contamination of sealing elements during high-pressure operation. By maintaining a moisture-free environment in the protective space, the sealing elements are protected from premature curing and degradation, reducing wear and maintenance frequency despite operating pressures above 30 bar
Solution Approach 2:
The system achieves self-protection by using the protective medium to automatically prevent adhesive from contacting and degrading sealing elements. The protective space design allows the system to self-maintain seal integrity without external intervention, reducing maintenance effort despite high-pressure operation
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 ensures reliable, efficient, and precise application of adhesives with reduced seal wear and clogging, allowing for larger nozzle-to-material distances and lower maintenance efforts, achieving high jet velocities and extended device lifespan.
Implementation Method 1
One-component adhesives are known which harden as soon as they come into contact with moisture. These adhesives are sometimes also referred to as moisture-curing cold glue or moisture-curing adhesive.
Implementation Method 2
Each of the nozzle openings can be actuated by a high-pressure needle valve or high-pressure piston valve with a needle or piston that can be moved up and down
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3
AI summary
The device has multiple nozzle openings and adhesive supply system (15), where adhesive is delivered by a portion of the system. The openings are operated by a high pressure needle valve or high pressure piston valve with a needle or piston (19). A protective region (40) is arranged in a rear region of the needle or piston. The protective region surrounds the needle or the piston in a sealing manner, and the protective region is applied with a protective medium (SM) e.g. liquid and air. Ring-shaped sealing elements (41, 42) surround the needle or the piston. An independent claim is also included for a method for discharging an adhesive bead- or adhesive sheet.