Open-Cell Foam Patches for Window Weep Holes
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Solution Overview
Problem
Existing window frames with weep holes are prone to clogging due to non-uniform sealant gaps, which can lead to water intrusion and insect infestation, especially in rainy areas, as the gaps can become too narrow or blocked by debris and insects, failing to effectively shed rainwater during water penetration tests.
Innovation Solution
Incorporating thin, open-cell foam patches with adhesive on the nail fin of the window frame, covered with a protective layer, to create engineered weep holes that wick water and prevent insect intrusion, ensuring uniform and effective water drainage and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are left in the sealant bead to create weep holes, then water can drain to the outside of the building, but insects and debris can block the gaps, limiting or blocking water escape
Solution Approach 1:
The patent uses open-cell foam patches with controlled porosity to create weep holes. The foam structure allows water to pass through via capillary action while the closed-cell portions prevent insect penetration. This resolves the contradiction by providing a porous material that drains water effectively without creating openings that insects can exploit.
Solution Approach 2:
The invention combines different foam cell structures (open-cell and closed-cell) within a single foam patch material. The open-cell regions facilitate water drainage while the closed-cell regions act as insect barriers. This composite material approach simultaneously achieves effective water shedding and insect prevention.
2Reliability
If gaps in the sealant bead are made for weep holes, then water can escape, but the gaps may not be uniform and some may be too narrow, especially if the sealant has spread
Solution Approach 1:
The open-cell foam patches provide uniformly controlled pore sizes through manufacturing processes, ensuring consistent water drainage capability. The foam structure's uniformity is maintained regardless of sealant spread, as the foam dimensions and pore characteristics are predetermined by the manufacturing process rather than being dependent on sealant application variability.
3Reliability
If weep holes are provided in the window frame, then water can drain to the outside, but the weep holes may act as entry points for water during water penetration tests
Solution Approach 1:
The foam patch combines open-cell and closed-cell structures where the closed-cell portions create water-tight barriers that prevent water penetration during testing, while the open-cell portions maintain water drainage functionality. This composite structure allows the weep hole to pass water during normal conditions but block water during penetration tests.
Solution Approach 2:
Different regions of the foam patch have different cell structures tailored to specific functions: open-cell regions for water drainage and closed-cell regions for water resistance during testing. This local differentiation of material properties allows the same component to perform both drainage and water-blocking functions simultaneously.
4Reliability
If the sealant bead is applied to seal the window frame, then water intrusion is prevented, but the sealant gaps become clogged with insects and dirt over time
Solution Approach 1:
The open-cell foam structure provides a self-cleaning effect where water flow through the porous material prevents insect and debris accumulation. The uniform pore structure allows continuous water passage that prevents clogging, maintaining long-term durability of the weep hole function while preserving the sealing performance of the sealant.
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 open-cell foam patches provide a reliable and uniform pathway for water drainage while blocking insects, reducing installation errors and ensuring a precise seal, thus effectively preventing water intrusion and insect entry, even in harsh weather conditions.
Implementation Method 1
The foam patches, preferably two spaced-apart foam patches, are immediately adjacent to the ends of the sealant bead that is applied around the sides and top of the nail fin so as to limit the intrusion of the water and confine the water so it must run to the bottom of the window frame, constrained along its way by the sealant bead on the fin and water-proof cover, until the water reaches the open cells of the two spaced-apart foam patches at the bottom of the nail fin. From there it proceeds directly to the outside of the building.
Implementation Method 2
at least one thin, open-cell foam patch with open edges and an adhesive on its broad sides that is then covered with a protective, peelable cover over the adhesives on both broad sides
Data Source
AI summary
In an extruded window frame, engineered foam patches are attached to the window frame for delivery to the job site. In combination with a sealant bead that is applied at the job site to the perimeter of the nail fin on the window frame, the foam patches serve as weep holes. Moisture reaching the interior of the rough framed opening of the building after installation of the windows is channeled between the sealant bead and the inside of the window frame. The foam patches, applied as a spaced-apart pair to the inside surface of the nail fin are in physical contact with the sealant bead to receive channeled rainwater, which can flow by gravity to the bottom of the window frame and exit the window. The foam patches block entry of insects.