Hot Melt Adhesive Nozzle Heating With Adjustable Valve Stroke
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Solution Overview
Problem
Conventional hot melt adhesive dispensers face challenges in maintaining consistent temperature across the nozzle while isolating it from other components, and the fixed stroke length of the valve member limits their versatility across different dispensing applications.
Innovation Solution
A dispenser module with a stroke adjustment assembly that includes a locking collar and adjustment rod, allowing for adjustable stroke length and thermal isolation of the valve member from the heater block, ensuring consistent heat distribution across the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength materials are used for the dispenser components to withstand high impact forces, then the strength is improved, but the thermal conductivity decreases resulting in poor heat distribution
Solution Approach 1:
The dispenser is divided into separate components: a heater block that generates heat, a nozzle body that receives heat, and a valve assembly that is thermally isolated. This segmentation allows different materials to be used in different zones - high thermal conductivity materials in the heater block and high strength materials in the valve assembly - resolving the contradiction between strength and thermal conductivity.
Solution Approach 2:
The valve assembly is extracted and thermally isolated from the heater block using insulating structures. This allows the valve assembly to be made from high strength materials to withstand impact forces while the heater block maintains high thermal conductivity for efficient heat distribution to the nozzle.
2Device complexity
If the stroke length of the valve member is fixed, then the structural simplicity is maintained, but the adaptability to different dispensing applications is reduced
Solution Approach 1:
The stroke adjustment assembly enables dynamic adjustment of the valve member stroke length. The adjustment rod with indexing features and locking mechanism allows the stroke to be changed between different preset positions, providing adaptability to various dispensing applications while maintaining a relatively simple overall structure.
3Speed
If the valve member is pneumatically operated at high velocities, then the dispensing speed is improved, but the thermal isolation requirements increase to protect pneumatic components from high temperatures
Solution Approach 1:
The pneumatic valve assembly is extracted and thermally isolated from the heated zones of the dispenser. Insulating structures physically separate the temperature-sensitive pneumatic components from the high-temperature adhesive flow path, enabling high-velocity pneumatic operation while protecting the components from thermal damage.
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 enables reliable and adjustable dispensing of hot melt adhesive with consistent temperature and improved performance across various applications by maintaining heat concentration within the nozzle and preventing heat transfer to other components.
Implementation Method 1
a stroke adjustment assembly that comprises an adjustment rod configured to contact the valve member, and a locking collar configured to alternate between an unlocked and a locked configuration, where 1) in the unlocked configuration, the adjustment rod is movable relative to the locking collar to adjust the stroke length
Implementation Method 2
the dispenser must consistently maintain certain temperatures throughout parts of the dispenser through which the adhesive flows in order to ensure uniform adhesive characteristics exist across the system
Implementation Method 3
portions of the dispenser, such as pneumatically operated components, function best when isolated from the high temperatures required by the adhesive
Data Source
AI summary
A dispenser for dispensing a liquid onto a substrate is disclosed. The dispenser includes a liquid supply and a dispenser module. The dispenser module includes a nozzle body having an inlet, an outlet, and a chamber for receiving the liquid. The dispenser module also includes a central valve body attached to the nozzle body that defines a piston chamber and a valve member having a piston portion disposed within the piston chamber of the central valve body and a needle portion extending form the piston portion into the chamber of the nozzle body. The dispenser further includes a heater block for heating the nozzle body. The heater block defines a liquid passage for transporting liquid from the liquid supply to the dispenser, a first surface of the heater block directly contacts the nozzle body, and the entirety of the central valve body is spaced from the heater block.