Liquid Container Headspace Formation via Segmented Path
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Solution Overview
Problem
Conventional liquid blow molding methods face issues with air entrainment in the liquid supply path, leading to instability in molding conditions and moldability, as the liquid inside the container is initially filled with air from the preform, which complicates the formation of a precise headspace in the container.
Innovation Solution
A liquid container manufacturing method using a nozzle unit with a blow nozzle, discharge rod, and gas supply port, where the liquid is discharged from the container under closed liquid supply path conditions, and pressurized gas is used to assist in forming a headspace, with the gas supply stopped once a set pressure is reached, ensuring precise control over the headspace formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the liquid inside the container is drawn in through the blow nozzle to create negative pressure and introduce air into the container to form headspace, then the headspace is formed, but air becomes entrained in the liquid supply path causing deterioration in molding stability and moldability
Solution Approach 1:
The liquid supply path is segmented into two separate paths: a first liquid supply path for supplying liquid during blow molding, and a second liquid supply path for discharging liquid after molding. This segmentation prevents air entrained during headspace formation from contaminating the blow molding liquid supply path, thereby maintaining molding stability while enabling precise headspace formation.
Solution Approach 2:
A discharge valve is introduced as an intermediary component to control the liquid discharge process. The discharge valve opens to allow liquid discharge and headspace formation, then closes to seal the second liquid supply path, preventing air from entering the supply path. This intermediary mechanism enables precise control over the headspace formation process while maintaining system reliability.
2Ease of manufacture
If conventional liquid blow molding method is used to manufacture liquid container, then low-cost manufacturing is achieved by omitting filling step, but air entrapment in supply path causes deterioration in molding conditions and moldability
Solution Approach 1:
The liquid supply system is divided into separate paths for blow molding and headspace formation. This allows the conventional liquid blow molding process to continue unchanged (maintaining low cost), while the separate second path handles air-sensitive operations, preventing air entrapment issues without adding significant complexity.
Solution Approach 2:
The discharge valve acts as a mediator that enables the low-cost liquid blow molding process to function reliably by controlling when liquid is discharged and when paths are sealed. It allows the system to maintain the simplicity and low cost of liquid blow molding while preventing the air entrapment problems that would otherwise occur.
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 method enables the production of liquid containers with precise capacity and shape at a low cost, improving stability and moldability by preventing air entrainment and ensuring accurate headspace formation.
Implementation Method 1
supplying pressurized liquid into the preform through the liquid supply port by the pressurized liquid supply source
Implementation Method 2
discharging the liquid out of the liquid container through the discharge port by drawing-in by the liquid drawing source
Implementation Method 3
supplying pressurized gas from the pressurized gas supply source into the liquid container through the gas supply port to thereby assist the discharge
Data Source
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AI summary
A liquid container manufacturing method includes: a liquid blow molding step of molding a preform (2) into a liquid container (C); and a headspace formation step of forming a headspace (H), by discharging, in a state in which a liquid supply path is closed, a liquid (L) out of the liquid container (C) through a discharge port (28a), the discharge accomplished by drawing-in by a liquid drawing source (33). In the headspace formation step, a pressurized gas is supplied from a pressurized gas supply source (38) into the liquid container (C) through a gas supply port (23c) to thereby assist the discharge, by the drawing-in, of the liquid (L) out of the liquid container (C) through the discharge port (28a), and, when a pressure in a discharge path has increased to a set value, the supply of the pressurized gas by the pressurized gas supply source (38) is stopped.