Plastic Bell Joint Sealing Lip Against Root Intrusion
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Solution Overview
Problem
Plastic pipes with bell joints are susceptible to invasive plant roots penetrating through the gasket, leading to hydraulic sealing impairment and pipe obstruction, requiring costly maintenance and replacement.
Innovation Solution
A plastic pipe with a bell joint featuring an annular closing lip on the inner wall that deforms to compress the male end, forming a tight seal and preventing root penetration by creating an annular cavity that blocks invasive roots, made through machining or thermoforming processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gasket is used in the bell joint to ensure hydraulic sealing, then the sealing performance is improved, but the gasket is vulnerable to root penetration and damage over time
Solution Approach 1:
The closing lip is formed on the inner wall of the bell joint before assembly, creating a preliminary barrier that prevents roots from reaching the gasket. This preliminary protective structure is integrated into the bell joint manufacturing process, ensuring the gasket is protected from the outset rather than requiring additional protective measures during assembly or operation.
Solution Approach 2:
The closing lip acts as an intermediary barrier between the external environment (where roots originate) and the gasket. It intercepts and blocks roots before they can contact the gasket, thereby protecting the sealing function without interfering with the gasket's primary sealing role.
2Ease of manufacture
If the bell joint is made with a simple structure to reduce manufacturing complexity, then production cost is reduced, but root penetration pathways are not effectively blocked
Solution Approach 1:
The inner wall of the bell joint is segmented into functional zones: the closing lip forms a distinct protective segment that blocks root penetration, while the rest of the bell joint maintains its standard structure for sealing and connection. This segmentation allows the addition of protective functionality without completely redesigning the entire bell joint structure.
Solution Approach 2:
The closing lip provides localized protection at the critical area where root penetration is most likely to occur (the interface between the bell joint and inserted pipe). Rather than requiring the entire bell joint to be complex, only the specific region needing root protection is modified with the closing lip structure.
3Object-affected harmful factors
If the closing lip is made rigid to effectively block roots, then root penetration resistance is improved, but the joining process becomes more difficult
Solution Approach 1:
The closing lip is designed with dynamic characteristics that allow it to deform elastically during the joining process when the pipe is inserted, facilitating easy connection. Once the pipe is in place and the joint is formed, the closing lip maintains its structural integrity to provide rigid protection against root penetration. This dynamic behavior reconciles the contradiction between ease of joining and root 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 solution effectively prevents plant roots from entering and damaging the gasket, maintaining hydraulic sealing and reducing maintenance costs by forming a robust and long-lasting barrier against root intrusion.
Implementation Method 1
The closing lip 7 deforms so as to adhere to and firmly and robustly abut the external wall 24 of the further pipe 21
Implementation Method 2
The closing lip 7 is in a single body with the pipe 1 and is made directly on the inner wall 4 by machining with stock removal... Alternatively, the closing lip 7 is made by a thermoforming process
Implementation Method 3
the closing lip 7 is made by a thermoforming process of the inner wall 4, i.e. during the hot forming of the bell joint 3 on the female end 2 of the pipe 1
Data Source
AI summary
A pipe made of plastics includes a female end with a bell joint suitable to receive a male end of another pipe and an inner wall with a seat for a gasket suitable to abut an external wall of the male end. When the pipe and other pipe are connected, a joint is formed having a hydraulic seal. The inner wall of the bell joint has at least one closing lip with an annular shape, which extends towards the inside of the bell joint, towards an external front edge of the bell joint, and includes an abutment edge, which adheres to, and tightens with a predefined force, the external wall of the male end. The closing lip is interposed between the external front edge and the seat and forms, with the inner wall, an annular cavity that opens in the direction of the external front edge.