Spiral-Rib Drainage Stack for Pressure Fluctuation and Noise Reduction
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Solution Overview
Problem
Plastic building drainage pipes with smooth inner walls experience high frictional resistance, leading to violent pressure fluctuations and noise, which can damage water seals and cause stink phenomena in toilets due to accelerated water flows.
Innovation Solution
A helical inner rib with a radial cross section following a normal distribution curve is arranged on the inner wall of the drainage stack, reducing pressure fluctuations and falling water velocity, and a helical blade with rounded corners is used to avoid stress concentration and prolong service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a smooth inner wall is used in plastic drainage pipes, then frictional resistance is low and water flow velocity is high, but violent pressure fluctuations and noise occur which can damage water seals and cause stink phenomena
Solution Approach 1:
The patent applies local quality by adding helical ribs only at specific locations on the inner wall of the drainage pipe, rather than making the entire surface rough. The helical ribs are positioned to create localized turbulence that increases frictional resistance and reduces water flow velocity, while the rest of the smooth inner wall maintains low overall friction. This localized modification effectively reduces pressure fluctuations and noise without significantly compromising drainage capacity.
2Reliability
If helical inner ribs are added to reduce water flow velocity and pressure fluctuations, then service life is prolonged, but the structure becomes more complex and manufacturing cost increases
Solution Approach 1:
The patent employs curvature by designing the helical ribs with rounded corners instead of sharp edges. The cross-section of each helical rib features curved surfaces that transition smoothly, eliminating stress concentration points. This curved geometry not only prolongs service life by preventing crack initiation but also simplifies the molding process compared to sharp-edged ribs, as the curved surfaces can be directly formed during injection molding without additional machining steps.
3Object-generated harmful factors
If helical blades with sharp corners are used to control water flow, then pressure fluctuations are reduced, but stress concentration occurs which shortens service life
Solution Approach 1:
The patent applies curvature by replacing sharp corners with rounded surfaces on the helical blades. The cross-sectional geometry of each blade incorporates curved transitions at all corners and edges, which distribute stress evenly throughout the structure. This eliminates stress concentration points that would otherwise serve as initiation sites for cracks and failure, thereby significantly prolonging service life while maintaining the pressure fluctuation control function.
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 solution effectively reduces pressure fluctuations and noise, prolongs the service life of the drainage stack by minimizing stress concentration and abrasion, and improves the water flow attachment effect, while maintaining a simple and cost-effective structure.
Implementation Method 1
plastic pipes with smooth inner walls have low frictional resistance... water flows are less influenced by pipe wall frictional resistance, descend quickly, and form accelerative flows
Implementation Method 2
the inner side of the radial cross section of the helical blade (2) is presented as a first normal distribution curve... improves the water flow attachment effect
Data Source
AI summary
The invention discloses a building drainage riser, its forming mold and forming method. The riser comprises a riser body and at least one spiral blade. The spiral blade is in a spiral direction on the inner wall of the riser body, and the spiral blade is fixedly connected to the inner wall of the riser body through its bottom side; the inner side of the radial section of the spiral blade presents the first normal distribution curve and the first normal distribution The abscissa axis of the curve is located on a chord of the inner wall of the riser body, and the distance from the chord to the center of the riser body is greater than half of the inner diameter of the riser body and less than the inner diameter of the riser body. The inner wall of the building drainage riser is provided with a spiral inner reinforcement with a radial section inside the first normal distribution curve, which completely eliminates the sharp tip and the sharp joint between the top and the inner wall of the building drainage riser, reduces the pressure fluctuation in the pipe during drainage and reduces the falling water flow speed. In addition, the molding die and forming method have the advantages of simple structure and low cost.