Irrigation Pipe Coupling Bulge Stress Distribution

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Solution Overview

Problem

Couplings for irrigation systems fail to effectively manage the increased stress in the circumferential direction of lay-flat irrigation pipes under internal hydrostatic pressure, leading to potential deformation and leakage issues.

Innovation Solution

A coupling design featuring an inner member with a bulge and a bore, and an outer member with a clamp and shank, where the bulge abuts the clamp under pressure to share stress and maintain fluid retention, utilizing a polyolefin material for durability and ease of assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional coupling design is used without a bulge, then the structure is simpler and easier to manufacture, but the coupling fails to effectively manage the increased stress in the circumferential direction of the pipe under internal hydrostatic pressure

Engineering Contradiction:
Improvestress management capabilityVSAvoidcoupling structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing a bulge at the specific location where the clamp contacts the pipe. This localized structural modification concentrates the stress-bearing capability exactly where needed - at the interface between the clamp and pipe - without requiring complex changes to the entire coupling structure. The bulge creates a localized stress distribution optimization that enhances reliability at the critical stress point.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The coupling is segmented into distinct functional components: the inner member with the bulge that contacts the pipe, and the outer member with the clamp that provides external support. This segmentation allows each component to be optimized independently - the bulge handles circumferential stress while the clamp provides overall structural support - resolving the contradiction between simplicity and stress management capability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the bulge projects further out of the pipe, then the stress distribution improves, but the coupling size increases and storage efficiency decreases

Engineering Contradiction:
Improvestress distributionVSAvoidcoupling projection volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The bulge projects only partially beyond the pipe surface - enough to provide effective stress distribution (sufficient action) but not excessively far (avoiding waste). This partial projection optimizes the balance between stress management capability and space efficiency, implementing just the right amount of structural extension needed for reliable operation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent optimizes the bulge projection distance as a critical parameter. By carefully controlling this dimensional parameter, the design achieves effective stress distribution while minimizing the volume occupied by the coupling when not in use. This parameter optimization directly addresses the contradiction between reliability and storage efficiency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the coupling is designed to be tightly secured under pressure, then fluid retention is maintained, but disassembly becomes more difficult

Engineering Contradiction:
Improvefluid retentionVSAvoiddisassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling design creates a dynamic interaction between the bulge and clamp where the contact pressure adjusts automatically based on the internal hydrostatic pressure of the pipe. Under pressure, the bulge expands and presses against the clamp, enhancing fluid retention. When pressure is released, the bulge relaxes, allowing for easier disassembly. This dynamic behavior resolves the contradiction between secure attachment and ease of disassembly.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2164643B1Irrigation pipe coupling
Publication Date: 2013.04.03 NETAFIM LTD
  • EP2164643B1 patent drawingFigure 1~3
  • EP2164643B1 patent drawingFigure 4~5

AI summary

An irrigation pipe coupling (16) for connecting to a lay flat irrigation pipe (10), comprises an inner member (36) comprising a bulge (50) and a bore (42), the bore (42) being formed about an axis (B) in the inner member (36) an the bulge (50) at least partially surrounding the axis (B); and an outer member (18) comprising a clamp (24) and a shank (22), the clamp (24) at least partially surrounding a base (32) of the shank (22); wherein the coupling (16) is adjustable between a disassemled position in which the inner and outer members (36,18) are separated from each other, and an assembled position in which the shank (22) of the outer member (18) is retained in the bore (42) of the inner member (36) and at least a portion of the inner member's bulge (50) is located between the shank (22) and the clamp (24).