Pressure Equalization Ring Radial Expansion for Underground Jacking
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Solution Overview
Problem
Existing pressure equalization rings for underground pipe jacking do not adequately distribute compressive stresses and provide effective barriers against dirt and media ingress, while also ensuring sufficient sealing and lubrication during the jacking process.
Innovation Solution
A pressure equalization ring composed of two elastomer components: a pressure ring and cuff rings with a C- or U-shaped cross-section, featuring a peripheral collar ring on the inside and/or outside, which acts as a dirt barrier, seal, and lubricant reservoir, allowing radial expansion to reduce tensile stresses and improve sealing and barrier functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple pressure equalization ring is used, then the device complexity is reduced, but the ability to distribute compressive stresses and provide sealing is insufficient
Solution Approach 1:
The pressure equalization ring is divided into multiple functional segments: a pressure transmission ring for stress distribution, inner and outer sealing rings for barrier functions, and connecting webs for structural integration. This segmentation allows each component to specialize in specific functions, improving overall reliability without requiring an entirely complex redesign.
Solution Approach 2:
The pressure equalization ring is designed as a multi-functional integrated component where the pressure transmission ring, sealing rings, and connecting webs work together to simultaneously achieve stress distribution, sealing, and structural stability. This multi-functionality reduces the need for separate components, maintaining simplicity while enhancing performance.
2Ease of manufacture
If the pressure equalization ring is made entirely of elastomer, then the manufacturing precision and ease of manufacture are improved, but the structural strength under maximum pressing forces may be insufficient
Solution Approach 1:
Different regions of the pressure equalization ring are designed with different geometric characteristics to optimize local performance. The pressure transmission ring has a specific cross-sectional shape and thickness distribution to handle compressive loads, while the sealing rings have profiles optimized for creating barriers. This local quality differentiation allows the entire structure to be made of elastomer while maintaining sufficient strength.
Solution Approach 2:
The pressure equalization ring utilizes composite geometric structures within the elastomer material, combining different cross-sectional profiles and thickness variations to achieve both manufacturing simplicity and structural strength. The integrated design of pressure transmission and sealing functions in a single elastomer component creates a composite structure that leverages the material's elasticity while providing enhanced load-bearing capacity.
3Strength
If the pressure ring is allowed to widen radially without constraints, then the tensile stresses on end ring surfaces are reduced, but direct contact with dirt and media increases wear
Solution Approach 1:
The inner and outer sealing rings act as intermediary barriers between the pressure transmission ring and the external environment. These sealing rings prevent direct contact between the pressure ring and dirt or media while still allowing the pressure ring to widen radially. The sealing rings create a protective interface that enables the pressure ring's stress-distributing function without exposing it to harmful factors.
Solution Approach 2:
The sealing rings are positioned concentrically around the pressure transmission ring, creating a nested structure where the pressure ring is enclosed within the protective barrier of the sealing rings. This nested arrangement allows the inner pressure ring to perform its stress-distributing function while being protected by the outer sealing rings from dirt and media ingress.
4Object-affected harmful factors
If sealing between jacking pipes is made absolutely hermetic with sleeve rings, then the barrier against dirt and media is improved, but some leakage is acceptable and complicates the structure
Solution Approach 1:
The sealing rings are designed to provide substantial barrier protection against dirt and media ingress, achieving sufficient sealing performance without requiring absolutely hermetic seals. This partial sealing approach is adequate for the application requirements and avoids the complexity and potential failure points of attempting to create perfect seals. The design accepts that some leakage may occur while still providing effective protection against harmful factors.
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 distributes compressive stresses, prevents dirt and media ingress, and enhances sealing and lubrication, thereby reducing friction and wear, and is designed to withstand maximum pressing forces without damaging the jacking pipes.
Implementation Method 1
The pressure equalization ring consists entirely of an elastomer... reduces locally high compressive stresses and distributes them at least partially in the circumferential direction
Implementation Method 2
An intermediate space is provided between the sleeve rings and the pressure ring, in which a lubricant is located, which reduces the friction between the pressure ring and the sleeve rings
Data Source
Figure 1~2
Figure 3a~3b
AI summary
The ring (1) has a pressure ring (2) and sleeve rings (3, 4) on a periphery of an inner side or an outer side of the pressure ring, where an annular end surface (5) of the pressure ring extends inside end walls (9) of the sleeve rings. An intermediate space (21) is provided between the end surface of the pressure ring and the end walls of the sleeve rings, where the inner cross-section of the sleeve rings is large to absorb the pressure ring when the pressure ring is compressed axially to the maximum.