Flexible Reservoir Venting for Drain Stack Pressure Attenuation
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Solution Overview
Problem
High-rise building drainage systems face challenges in effectively suppressing and alleviating pressure transients, leading to noise, water seal issues, smell problems, and potential virus transmission, with existing solutions requiring additional space and not adequately addressing air transient pressure in large buildings.
Innovation Solution
A positive air pressure attenuation device integrated into the main drainage stack, featuring a housing with an elastic flexible reservoir that connects to the drainage system, allowing air to contact atmospheric air, and a specific design of openings to manage pressure transients, capable of withstanding pressures up to 20kPa and reducing air pressure surges by up to 90%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positive air pressure attenuation device is mounted adjacent to an air admittance valve as in prior art, then the device can attenuate pressure transients, but extra space is required and extra junctions are needed
Solution Approach 1:
The patent combines the air pressure attenuation device with the air admittance valve into a single integrated unit. The housing of the attenuation device serves as the body of the air admittance valve, eliminating the need for separate mounting and reducing installation complexity while maintaining pressure transient attenuation functionality.
Solution Approach 2:
The device performs multiple functions within a single structure: it acts as both an air pressure attenuation device and an air admittance valve. The flexible reservoir provides pressure attenuation while the valve mechanism within the same housing provides air admission control, reducing the number of components needed in the drainage system.
2Quantity of substance
If the drainage stack diameter is increased to 150-200mm for high rise buildings, then the system can handle larger air volumes, but the problem of air transient pressure is not adequately solved
Solution Approach 1:
The patent uses a flexible reservoir that can dynamically change its volume in response to pressure variations. The reservoir expands when subjected to positive pressure transients and contracts during negative pressure transients, providing adaptive pressure attenuation that is effective for large air volumes in high-rise building drainage stacks with diameters of 150-200mm.
Solution Approach 2:
The patent employs a flexible reservoir made of elastic material that can withstand and respond to pressure transients. This flexible structure allows the device to effectively attenuate large air volume transients in large-diameter stacks by deforming elastically under pressure loads, solving the inadequacy of rigid structures in high-rise applications.
3Strength
If a 1mm thick elastic rubber flexible reservoir is used, then the device can withstand positive air pressure transients up to 20kPa, but the device requires integration into the main drainage stack which limits installation locations
Solution Approach 1:
The integrated design allows the device to be installed directly into the drainage stack at various locations without requiring separate mounting space. The combination of pressure attenuation and air admittance functions in one unit enables installation at convenient locations in the drainage system, improving ease of operation while maintaining pressure resistance.
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 device effectively attenuates both positive and negative pressure transients in high-rise buildings, reducing noise and smell issues while minimizing space requirements, and is suitable for large drainage stacks, providing a solution for tall buildings by equalizing negative reflections within the main drainage pipe.
Implementation Method 1
an elastic flexible reservoir (8) associated to the inner central portion (6) of the pipe (3A), the reservoir (8) being operable on a positive air pressure transient within the drainage system (D)
Implementation Method 2
Tests with a device of the invention have proved that it was a perfect in-line device effective at attenuating the type of pressure surge experienced in very tall buildings
Implementation Method 3
an external casing (3) covering at least partly the flexible reservoir (8) and having at least one air passage way (10) adapted for ensuring at least the portion of the flexible reservoir located into the housing (3) to be in contact with atmospheric air during operation of the device
Data Source
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AI summary
A positive air pressure attenuation device (1) comprising: - a housing (3) with an inner central portion (6) forming a channel (7); and - an elastic flexible inflatable reservoir (8) associated to the inner central portion (6), whereby the inner central portion (6) has a wall portion (60) with a plurality of openings (61) forming passages between the channel (7) and the reservoir chamber (8A).