Injection Head Nozzle Segmentation for Preform Sealing
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Solution Overview
Problem
Existing blow molding apparatuses face issues with leakage and contamination due to the retention and leakage of injection liquids in the nozzle, leading to malformations, cleanliness concerns, and increased production costs.
Innovation Solution
An injection head with a first nozzle featuring an annular mouth seal and a second nozzle with a shoulder seal, along with a compensation fluid channel, to create a secure seal with the preform and minimize fluid leakage, allowing for precise control over the injection process and reducing the dead volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bell-shaped nozzle is used to create a seal with the mold surface, then sealing is achieved, but injection liquid is retained in the space above and around the preform causing leakage and contamination
Solution Approach 1:
The nozzle is divided into multiple segments: a first nozzle portion that creates a first seal with the preform mouth, and a second nozzle portion that creates a second seal with the preform neck ring. This segmentation prevents liquid retention by ensuring each seal is made directly with the preform surface, eliminating the problematic space above the preform that existed in the bell-shaped design.
Solution Approach 2:
The invention extracts and eliminates the problematic intermediate space between the nozzle and preform that caused liquid retention. By making direct seals with the preform mouth and neck ring, the design removes the void space where injection liquid would be trapped and subsequently leak, thereby eliminating the harmful effect without compromising sealing functionality.
2Reliability
If the nozzle creates a seal with the mold surface, then sealing is achieved, but liquid leaks from the injection nozzle when the seal is broken
Solution Approach 1:
The sealing function is segmented into two distinct sealing locations: the first seal at the preform mouth and the second seal at the preform neck ring. This segmentation ensures that when the injection head is retracted, liquid cannot leak from either seal location because both seals are made directly with the preform surface, eliminating the contamination problem associated with single-point sealing.
Solution Approach 2:
The preform itself acts as an intermediary sealing surface between the nozzle and the mold. Instead of the nozzle sealing directly with the mold surface (which creates problematic spaces), the preform mouth and neck ring serve as intermediate sealing surfaces, ensuring liquid-tight seals that prevent leakage and contamination when the seal is broken during retraction.
3Productivity
If injection liquid is used instead of gas, then forming and filling steps are combined, but liquid is retained in the nozzle space causing malformations and cleanliness concerns
Solution Approach 1:
The injection system is segmented into two sealing zones: the first nozzle portion sealing with the preform mouth and the second nozzle portion sealing with the neck ring. This segmentation allows liquid injection to proceed without retention because the segmented seals eliminate the dead space where liquid would be trapped, thereby maintaining process integration benefits while eliminating liquid retention problems.
Solution Approach 2:
The invention extracts and eliminates the dead volume or retention space that exists in traditional bell-shaped nozzles. By making direct seals with the preform surfaces at two locations, the design removes the intermediate space where injection liquid would be retained, allowing liquid injection to proceed without the harmful retention effect while maintaining the integrated forming-filling process.
4Reliability
If a secure seal is created with the preform, then pressure loss is prevented, but the nozzle structure becomes more complex
Solution Approach 1:
The sealing function is segmented into two separate sealing locations rather than one complex seal. The first nozzle portion creates a seal with the preform mouth, and the second nozzle portion creates a seal with the neck ring. This segmentation achieves superior pressure containment through multiple seal points while keeping each individual seal relatively simple in structure.
Solution Approach 2:
The injection head is designed with multi-functionality: the first nozzle portion serves both as an injection channel and a sealing element with the preform mouth, while the second nozzle portion similarly combines injection function with sealing against the neck ring. This multi-functionality reduces the need for additional separate sealing components, thereby containing pressure effectively without proportionally increasing structural complexity.
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 reduces fluid leakage, minimizes contamination, and enhances control over the expansion process, resulting in improved container quality and reduced production costs by eliminating the need for extensive cleaning and drying processes.
Implementation Method 1
the pressurized fluid is injected into the cavity of the preform through the injection head, thereby inducing the preform to undergo plastic deformation and expand to assume the contours of the mold
Implementation Method 2
it becomes necessary to provide a means in the nozzle of the injection head to create a secure seal with the preform, so as to avoid leakage of the pressurized fluid
Implementation Method 3
a stretching rod is inserted into the preform and urged against an interior surface thereof, inducing the preform to deform along its longitudinal axis
Data Source
AI summary
An injection head for a container-fabricating apparatus. The injection head includes a first nozzle establishing fluid communication between an injection liquid source and a preform cavity of a substantially tubular preform. The first nozzle is configured to mate with a mouth of the preform. An annular mouth seal, provided in the first nozzle, creates a seal with the mouth of the preform when disposed in contact therewith.