Moisture-Curing Adhesive Nozzle with Gas Jacket
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Solution Overview
Problem
Existing devices for applying moisture-curing adhesives face challenges such as premature hardening, clogging, and high maintenance due to the need to switch off individual nozzles, which leads to inefficient application and increased economic downtime, especially when handling polyurethane-based adhesives.
Innovation Solution
A device with multiple nozzle openings and switchable adhesive feeds, utilizing needle or piston valves that can be operated in two modes, where a gas stream is used to prevent adhesive residue and premature curing, allowing for adaptive application and reduced maintenance by creating a gas jacket around the adhesive as it exits the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If individual nozzles are switched off to adapt to workpiece size, then adhesive consumption is reduced, but the adhesive in closed nozzles hardens prematurely causing clogging and requiring extensive cleaning
Solution Approach 1:
The patent introduces a gas stream (inert atmosphere) into the flow chamber to displace moisture and prevent premature hardening of adhesive in closed nozzles. This allows nozzles to remain closed without clogging, while still enabling adhesive to be dispensed only where needed, reducing overall adhesive consumption.
2Reliability
If membrane valves are used to prevent premature hardening, then adhesive application reliability is improved, but the system cannot tolerate pressures above 20 bar and has limited service life
Solution Approach 1:
The patent uses a gas stream as an intermediary substance to protect the adhesive from moisture without requiring membrane valves. This eliminates the pressure limitation of 20 bar and extends service life, while still preventing premature hardening in closed nozzles.
3Adaptability or versatility
If multiple nozzles are kept open for future use, then application flexibility is maintained, but the adhesive in these nozzles dries out and hardens
Solution Approach 1:
The gas stream creates a protective environment in the flow chamber that prevents adhesive from hardening in closed nozzles. This allows nozzles to remain closed indefinitely without clogging, maintaining application flexibility while eliminating the need for extensive cleaning.
4Speed
If compressed air is used to convey adhesive through air ducts, then adhesive flow is improved, but leaks and drying out occur especially with moisture-curing adhesives
Solution Approach 1:
The patent replaces compressed air with a controlled gas stream that creates a moisture-free environment in the flow chamber. This prevents moisture-curing adhesives from hardening in the supply lines while still enabling smooth adhesive flow through the nozzle.
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
This solution enables efficient, adaptive application of adhesives with reduced premature curing and clogging, allowing for continuous operation and lower maintenance needs, particularly suitable for polyurethane adhesives, by using high-pressure nozzles and a gas jacket to protect the adhesive and prevent hardening.
Implementation Method 1
a gas supply (17) which is connected to the flow chamber (16), wherein the device has an outlet opening (14.1-14.4) in the area of the nozzle opening (11.1-11.4), which is arranged in such a way that when gas (G) is fed in through the gas supply (17) into the flow chamber (16) and when adhesive (K) is fed in through the adhesive channel (15) to the nozzle opening (11.1-11.4), adhesive (K) and gas (G) are simultaneously deliverable through the outlet opening (14.1-14.4)
Implementation Method 2
Each of the nozzle openings (11.1-11.4) has a needle or piston valve (19), preferably electromagnetically driven
Implementation Method 3
High-pressure nozzles with needle or piston valve are used. In contrast to the membrane-based application systems mentioned, such devices have the advantage that they achieve a jet velocity of the dispensed medium that is greater than 4 m/s
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3
AI summary
Method and apparatus for dispensing a moisture-curing adhesive (K). The apparatus (10) has several nozzle openings (11.1 - 11.4) and switchable adhesive supply lines (12). The apparatus (10) can be operated in a first operating mode or a second operating mode, wherein in the first operating mode adhesive (K) is dispensed through all nozzle openings (11.1 - 11.4) and in the second operating mode adhesive (K) is dispensed only through a smaller number of the nozzle openings (11.1 - 11.2). Each nozzle opening (11.1 - 11.4) is formed on or in a housing (13.1 - 13.4) in which an adhesive channel (15) is provided for supplying the adhesive (K) to the nozzle opening (11.1 - 11.4). For each nozzle opening (11.1 - 11.4), a flow chamber (16) is arranged in the region of the nozzle opening (11.1 - 11.4). A gas supply (17) is connected to the flow chambers (16). The device (10) has outlet openings (14.1 - 14.1).4) in the area of the nozzle opening (11.1 - 11.4), which are arranged such that when gas (G) is supplied through the gas supply (17) into the flow chamber (16) and when adhesive (K) is supplied through the adhesive channel (15) to the nozzle opening (11.1 - 11.4), adhesive (K) and gas (G) can be discharged simultaneously through the outlet opening (14.1 - 14.4).