Container Vent

Manufacturer of sealed containers for cultivating orchids seeks a way to better regulate container air quality and humidity. Great results bloom with Porex’s breathable vent – a vast improvement over previous designs that’s also easy to clean and replace.

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Design Challenge:
In the early stages of growth, orchids are cultured within sealed containers. The rate and uniformity of growth are affected by the humidity within the container and the success with which contaminants such as spores, bacteria and yeasts can be excluded over a period of fifteen months. To offer the market better results in cultivating orchids, a container manufacturer asked Porex to develop a vent to regulate air changes and humidity in a plant culture container, while maintaining its aseptic integrity. Creating this breathable vent required a method to regulate the number of air changes within the container while retaining a high internal water vapor pressure, which is essential to reduce nitrification without dehydration. Since the container was intended for use in small-scale horticultural environments, it was also important to make the vented container easy to use and replace.

Solution:
Careful selection of polymer granules of the correct shape and size is the most important factor in developing membranes designed to meet specific performance parameters. Porex engineers met this requirement, while also designing a product flexible enough to conform to the geometry of the container, through the use of a micro-porous PTFE material. The material allows the passage of air and water vapor, yet serves as a barrier to water in the liquid phase and to many airborne contaminants. The attachment requirements were solved by laminating an outer ring of adhesive on the disc-shaped vent.

Result:
The adhesive-laminated disc simplifies use, while allowing the open area (hence, the vent rate) to be controlled and reproducible. This represents a significant improvement over the cotton wool plugs used in previous designs. Similar designs have subsequently been adapted for membranes across a range of industries, including electronics and automotive applications.

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