Packaging Bag Ventilation Design for Cementitious Product Filling
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Solution Overview
Problem
Packaging bags for powdered filling materials, particularly cementitious construction chemical products, face issues with air pockets during filling, reduced filling efficiency, moisture ingress, and rapid degradation of chromate reducers due to atmospheric oxygen, leading to shortened shelf life and legal compliance challenges.
Innovation Solution
A packaging bag design featuring a longitudinal sealed seam with a ventilation channel as secondary ventilation, an outer layer of plastic film providing improved moisture protection and reduced oxygen ingress, combined with an inner layer of perforated plastic film to prevent air pockets and enhance filling efficiency, and a gusseted design for upright storage and easy stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bag is filled quickly to maintain high filling speed, then productivity is improved, but air pockets arise within the bag reducing effective filling volume
Solution Approach 1:
The bag structure is segmented into inner and outer layers with independent ventilation systems. The inner layer has air passage openings for primary ventilation during filling, while the outer layer has ventilation openings for secondary ventilation after closure. This segmentation allows air to be removed efficiently during rapid filling without compromising the outer layer's protective function.
Solution Approach 2:
The space between the inner and outer layers acts as an intermediary zone for air removal. Air passage openings in the inner layer allow displaced air to escape through this intermediate space before reaching the outer layer, enabling efficient deaeration during rapid filling while maintaining the integrity of the outer protective layer.
2Productivity
If ventilation openings are provided on the inner layer for primary ventilation, then air removal during filling is improved, but moisture can penetrate through the paper lining and air passage openings into the bag
Solution Approach 1:
The bag uses a composite structure combining an inner plastic layer with air passage openings and an outer paper layer with ventilation openings. The inner plastic layer provides controlled air removal through its perforations while the outer paper layer provides moisture protection. This composite design allows the benefits of both materials to work together synergistically.
Solution Approach 2:
Different parts of the bag have different properties optimized for their specific functions. The inner layer is designed with high permeability to air (perforated plastic) for efficient air removal during filling, while the outer layer is designed with moisture barrier properties (paper lining) to protect against moisture ingress. Each layer's local properties are optimized for its primary function.
3Productivity
If the outer layer is made of paper for ventilation, then gas exchange is improved, but the outer layer can become soaked with water during improper storage
Solution Approach 1:
The bag combines an inner plastic layer with an outer paper layer, where the plastic layer provides moisture protection and the paper layer provides ventilation. The plastic layer acts as a protective barrier that prevents water from reaching the paper layer during storage, while still allowing the paper layer to perform its ventilation function when needed.
Solution Approach 2:
The inner plastic layer serves as an intermediary protective barrier between the external environment and the outer paper layer. It allows controlled gas exchange while blocking moisture from reaching the paper layer, thus protecting the outer layer from water damage during storage while maintaining its ventilation capability.
4Reliability
If chromate reducers are added to convert water-soluble chromates, then legal compliance is improved, but the chromate reducers are passivated by air oxidation reducing shelf life
Solution Approach 1:
The bag creates a relatively inert environment inside by providing tight sealing and controlled ventilation. The inner plastic layer with its air passage openings allows controlled air exchange during filling but maintains a protected environment that slows down oxidation of chromate reducers during storage, extending their shelf life while maintaining compliance.
Solution Approach 2:
The packaging bag structure acts as an intermediary barrier between the chromate reducers and atmospheric oxygen. The multi-layer structure with controlled ventilation openings allows sufficient gas exchange for safety while minimizing oxygen exposure to the chromate reducers, thus protecting them from oxidation and extending shelf life.
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 design significantly reduces air inclusion during filling, extends the shelf life of chromate-containing products by minimizing moisture and oxygen exposure, and ensures compliance with legal limits for water-soluble chromates, allowing for longer storage without degradation, while maintaining adequate ventilation and structural integrity.
Implementation Method 1
the inner layer has air passage openings which allow the displaced air to be removed quickly and directly through the inner layer
Implementation Method 2
the outer layer being formed from a plastic film and the outer layer being permanent ventilation of the packaging bag after its closure, a secondary ventilation is provided, which allows a slow escape of gas
Implementation Method 3
the outer layer made of a plastic film provides improved protection against moisture and, in particular, also represents a diffusion barrier
Implementation Method 4
the inner layer is made of plastic and is provided with a large number of air passage openings or perforations
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The bag has a plastic inner layer (2) i.e. perforated foil, and an outer layer (1) sectionally connected with each other. The inner layer has air through-flow openings (9) for primary ventilation of an inner space of the bag during a filling process with powder dusty filling goods. The outer layer is formed of a plastic foil, and has a secondary vent for permanent ventilation of the bag after closing the bag and enabling slow gas leakage. A longitudinal sealing seam (6) with a ventilation channel is provided as the secondary vent in a region of a longitudinal edge (5) of the bag.