Injection Nozzle Shutter with Segmented Fluid Passages
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Solution Overview
Problem
The existing injection molding apparatuses for thermoplastic materials face issues with leakage of molten plastic particles into the upper chamber, leading to solidification and accumulation, which slows down or stops the piston stroke and requires frequent maintenance, causing labor-intensive downtimes.
Innovation Solution
The apparatus features a dual-chamber cylinder-piston system with distinct fluid passages for air and plastic particle exit, allowing for continuous removal of solidified plastic particles during the injection cycle without dismantling, using a separate channel for particle exit and integration of a three-way valve for controlling fluid flow to prevent re-introduction of particles into the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single opening is provided for each chamber for pressurization and depressurization, then the device complexity is reduced, but plastic particles leak into the upper chamber and accumulate, causing maintenance issues
Solution Approach 1:
The single opening for each chamber is segmented into two separate openings: a first opening for fluid introduction and a second opening for fluid and particle exit. This segmentation allows independent control of pressurization and depressurization pathways, preventing particle accumulation in the upper chamber while maintaining relatively simple device structure.
2Object-affected harmful factors
If the clearance between shutter and guide is minimized, then particle leakage is reduced, but the shutter cannot slide properly
Solution Approach 1:
A fluid flow path is introduced as an intermediary mechanism between the shutter and guide clearance. The fluid flow actively removes particles that leak through the necessary clearance, allowing the shutter to slide freely while preventing particle accumulation. This mediator approach decouples the clearance requirement from particle leakage prevention.
3Ease of manufacture
If the apparatus is dismantled for cleaning the upper chamber, then plastic particles are removed effectively, but production stops and labor time increases
Solution Approach 1:
The system performs self-cleaning through the dual-opening configuration. During normal operation, the second opening allows fluid flow to continuously remove particles from the upper chamber without requiring external intervention or dismantling. This self-service mechanism maintains cleaning effectiveness while ensuring production continuity.
4Ease of operation
If a dual-acting cylinder-piston system is used with two chambers, then shutter control is improved, but particle accumulation in the upper chamber occurs
Solution Approach 1:
The dual-chamber structure is maintained for shutter control, but each chamber's single opening is segmented into two openings. This additional segmentation enables particle removal functionality without adding complex external systems, balancing shutter control capability with particle accumulation prevention.
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 continuous operation by removing plastic particles at each injection cycle, preventing re-introduction into the chamber, thus reducing maintenance needs and maintaining production efficiency.
Implementation Method 1
a first passage for the introduction of fluid into the first chamber to take the shutter to the opening position
Implementation Method 2
a second passage, different from the first passage for the exit of fluid and possible plastic particles from the first chamber
Data Source
AI summary
An injection apparatus for injecting molten plastic into a mold of articles made of thermoplastic material including bottle preforms. The injection apparatus includes an injection nozzle and a shutter for controlling flow of the molten plastic through the injection nozzle. A cylinder-piston system moves the shutter from open and closed positions of the injection nozzle. The cylinder-piston system includes a first chamber with a first passage for introducing fluid into the first chamber to open the shutter, and a second passage, different from the first passage, for discharge of fluid and of possible particles from the first chamber. A fluid distribution device with a first channel is connected to the first passage, and a second channel different from the first channel is connected to the second passage. The cylinder-piston system includes a second chamber having a third passage for introducing fluid into the second chamber to close the shutter.