Variable Volume Hot Melt Adhesive Nozzle with Choke Slots
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Solution Overview
Problem
Conventional dual-component hot melt adhesive dispensing systems experience operational difficulties due to negative and positive pressure spikes, leading to gaps in dispensed volumes when switching between fluid flow states, which affect the accuracy and consistency of the dispensed adhesive.
Innovation Solution
Incorporation of choke slots within the fluid control plates to restrict and delay fluid flow, allowing built-up pressure and volume to be attenuated over time, smoothing transitions between fluid flow conditions and preventing adverse effects from pressure spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If volume control valves are used to control different fluid flows in a dual-component hot melt adhesive dispensing system, then variable volume deposition states can be achieved, but pressure spikes occur during valve switching that cause gaps in the dispensed adhesive
Solution Approach 1:
A pressure equalization chamber is introduced as an intermediary component between the fluid flows and the output nozzles. This chamber absorbs pressure spikes during valve switching by providing a buffer volume, preventing direct transmission of pressure variations to the dispensing system and eliminating gaps in the dispensed adhesive.
Solution Approach 2:
The pressure equalization chamber is designed to anticipate and cushion pressure spikes before they can affect the dispensing process. By pre-establishing a buffer zone, the system prepares for potential pressure variations during valve transitions, ensuring continuous and gap-free adhesive deposition.
2Adaptability or versatility
If one fluid flow is continuously supplied while another is cyclically opened and closed to achieve variable volume deposition, then different adhesive patterns can be created, but pressure spikes occur during cyclical valve operation that disrupt fluid flow stability
Solution Approach 1:
The pressure equalization chamber serves as a mediator that decouples the cyclical valve operation from the continuous fluid flow. It absorbs the intermittent pressure disturbances caused by cyclical valve switching, maintaining stable fluid flow conditions necessary for consistent adhesive pattern formation.
Solution Approach 2:
The chamber provides preemptive cushioning for pressure spikes generated during cyclical valve operation. By establishing a buffer capacity in advance, the system can accommodate repeated valve transitions without compromising fluid flow stability or adhesive pattern consistency.
3Adaptability or versatility
If multiple volume control valves operate simultaneously to achieve six potential volume deposition states, then comprehensive adhesive application flexibility is obtained, but pressure spikes from valve switching affect the accuracy and consistency of dispensed volumes
Solution Approach 1:
The pressure equalization chamber acts as a mediator that isolates the multiple volume control valves from each other and from the dispensing system. This allows independent operation of each valve to achieve different volume deposition states without pressure interference, ensuring accurate and consistent dispensed volumes across all six operational states.
Solution Approach 2:
The chamber provides preemptive pressure buffering for all possible valve switching scenarios. By establishing a sufficient buffer capacity in advance, the system can handle any combination of valve operations (single valve, dual valve, cyclical operation) without pressure spikes compromising volume deposition accuracy.
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 effectively isolates and reduces pressure spikes, ensuring continuous and consistent dispensing of hot melt adhesive, preventing gaps and maintaining desired volumetric flow levels during transitions.
Implementation Method 1
the inertial flow of the second volume of hot melt adhesive effectively undergoes, creates, or results in a negative pressure spike or drop
Data Source
Figure 1
Figure 2
Figure 3a~3g
AI summary
A dual, variable volume hot melt adhesive dispensing nozzle or die assembly is provided with a pair of choke slots (194, 208) within a first fluid control plate (166). The provision of the choke slots within the first fluid control plate effectively restricts and retards the flow of the fluid through such choke slots whereby volumes of the fluids are effectively built up and stored upstream of the choke slots so as to effectively delay the reaction of pressure spikes upon the fluid flows under both positive and negative conditions. This buildup in pressure and volume is then dispensed over time so as to cause the fluid flow to smoothly transition between positive and negative spiked fluid flow conditions and normal fluid flow conditions. Accordingly, the pressure spikes do not adversely affect the resulting fluid flows whereby, for example, under conventional negative pressure spike conditions, gaps in the dispensed hot melt adhesive would otherwise occur.