Expandable Foam Injection Head with Rotary Anti-Seize Control
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Solution Overview
Problem
Existing injection heads for polyurethane foams face issues with cured foam residue obstructing passages and causing rod seizure, requiring frequent maintenance due to inefficient cleaning methods.
Innovation Solution
An injection head design featuring a guiding cage with helical grooves and guide pins or radial pins and cams that induce a rotary motion during the shutter stem's sliding movement, preventing seizing by detaching adhered surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the control rod is moved to a forward position to close the inlet ports, then the injection nozzle is cleaned of residing residual components, but cured foam residue remains and causes progressive seizure of the rod
Solution Approach 1:
The invention transforms the static sliding motion of the control rod into a dynamic rototranslational motion by introducing a guiding cage with helical grooves. This dynamic motion creates continuous surface detachment, preventing cured foam residue from adhering to the rod and causing seizure, while still achieving effective cleaning of the injection nozzle.
Solution Approach 2:
The helical grooves in the guiding cage introduce a curved, rotational path to the control rod's motion. This curved trajectory ensures that the rod surfaces continuously rotate and detach from any adhered foam residue, preventing seizure while maintaining cleaning effectiveness.
2Ease of manufacture
If longitudinal sliding motion is used to remove fouling, then some cleaning is achieved, but cleaning efficiency is still low and seizure problems occur
Solution Approach 1:
The invention upgrades the static longitudinal sliding motion to a dynamic rototranslational motion through the helical guiding cage. This dynamic approach continuously detaches adhered surfaces, dramatically improving cleaning efficiency and preventing seizure while maintaining simple component structure.
Solution Approach 2:
The helical grooves create a vibrational or oscillating motion effect during the control rod's movement. This mechanical vibration action effectively disrupts and removes adhered foam residue, significantly improving cleaning efficiency compared to simple sliding motion.
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
Effectively reduces seizing and maintenance needs by ensuring the shutter stem rotates axially, maintaining smooth operation and reducing residue adhesion.
Implementation Method 1
a guiding cage (7) comprising a fixed constraining member, integral with the cylindrical body (2), and a helical follower element, integral with the shutter stem (3), wherein the sliding movement of the shutter stem (3) induces a rotary motion about its longitudinal axis
Implementation Method 2
The axial rotation action obtained in a passive manner... causes detachment between the surfaces of the stem (3) and those of the central supply duct and nozzle (6), even in the presence of polyurethane residue that tends to stick the surfaces together, thus avoiding undesirable seizing
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An injection head (1) for making hardening foams is disclosed, comprising a housing in which are housed an inflow and mixing body (5) equipped with a central supply duct connected to an injection nozzle (6) and a plurality of supply ducts (5a) of fluid components to be mixed converging on said central supply duct, and a shutter stem (3, 30) mounted sliding longitudinally at least partially in said central supply duct and injection nozzle (6) according to an alternating forward and backward movement which respectively closes and opens inflow ports of said supply ducts (5a) in said central supply duct, further comprising a guiding cage (7) arranged around said plug stem (3, 30) arranged to guide said shutter stem (3, 30) according to a rotation on its longitudinal axial upon said longitudinal sliding.