Double Hung Window Water Management System
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Solution Overview
Problem
Double hung windows face challenges in sealing against water penetration during driving rainstorms due to the complexity of their design, leading to inevitable leaks, especially at the transition from the upper sash seals to the lower sash seals and at the bottom corners, which can result in interior water leakage.
Innovation Solution
A water management system for double hung windows featuring interior and exterior pressure drop seals forming a U-shaped channel around the lower sash, with a bridge seal at the top and a vent channel at the bottom to maintain exterior pressure within the channel, preventing water from seeping into the interior by draining it externally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple compression seals are applied to seal against water penetration in double hung windows, then water sealing capability is improved, but device complexity increases and reliability decreases at transition areas
Solution Approach 1:
The window frame is divided into multiple sealed chambers (first chamber between upper sash and header, second chamber between lower sash and sill, third chamber between sashes) that are separated by sealed mullions. Each chamber has its own drainage path to the exterior, preventing water from penetrating across the entire window assembly even if seals at transitions fail.
Solution Approach 2:
Sealed mullions act as intermediary elements that divide the window frame into separate sealed chambers. These mullions provide both structural support and water separation functions, creating intermediate barriers that prevent water penetration between different sash levels.
2Reliability
If a reservoir is created to catch leaked water, then interior water leakage is reduced, but the reservoir may overflow during prolonged storms
Solution Approach 1:
Instead of creating a large interior reservoir to hold water, the invention extracts the water collection function to exterior drainage channels. Water that penetrates seals is channeled to the exterior through dedicated drainage paths at the bottom of each sealed chamber, preventing interior accumulation and overflow issues.
Solution Approach 2:
The invention converts potentially harmful water penetration into a controlled drainage process. Water that breaches seals is not allowed to accumulate interiorly but is instead directed through exterior drainage channels, turning a failure mode into a controlled water management system.
3Reliability
If seals are applied at all transition areas, then water penetration resistance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The window assembly is segmented into separate sealed chambers with standardized seal configurations at each chamber. This modular approach simplifies manufacturing by allowing standardized components to be assembled, rather than requiring complex custom seals at each transition point.
Solution Approach 2:
Sealed mullions serve as pre-fabricated intermediary components that incorporate necessary seals and drainage features. By manufacturing these mullions as separate sealed units, the complexity of seal installation is reduced to assembling these pre-sealed modules rather than installing multiple individual seals at each transition.
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 system effectively prevents water from entering the interior of the building by maintaining exterior pressure within the U-shaped channel, ensuring that any seepage flows harmlessly down and drains outside, thus enhancing the window's ability to withstand blowing rainstorms without interior leakage.
Implementation Method 1
a vent channel at the bottom to maintain exterior pressure within the channel
Implementation Method 2
interior pressure drop seals forming a U-shaped channel around the lower sash
Data Source
AI summary
A water management system for a double hung window prevents leakage between the lower sash and the frame of the window in a blowing rainstorm. The water management system comprises interior pressure-drop seals disposed between the vertical stiles of the lower sash and the jambs of the window frame and an interior pressure drop seal disposed along an interior edge of the bottom rail of the lower sash and the sill of the frame. Exterior shingling seals are disposed at least between outside edges of the sash and the jamb and the exterior shingling seals and the interior pressure-drop seals at least partially bound vertical channels. A vent communicates between the vertical channels and the outside environment to maintain the pressure in the vertical channels substantially the same as that of the outside environment. This prevents rainwater in a blowing rainstorm from violently breaching the exterior shingling seals and splashing onto the interior pressure-drop seals, which, in turn, prevents leaks into a home.