Resin Pipe Joint Inner Ring Geometry to Prevent Flow Backwaters

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Solution Overview

Problem

Resin tube fittings cause backwaters in fluid flows due to the inner protrusion bulging into the fluid channel, leading to fluid stagnation and precipitation, which increases flushing time and can result in particle formation.

Innovation Solution

The design includes an inner protrusion with a tapered or curved first inner peripheral surface that reduces in diameter towards the axial direction, preventing deformation into the fluid channel and ensuring smooth flow by maintaining a constant cross-sectional area, and the insert with sloped and angled surfaces that prevent bulging when the union nut is engaged, allowing fluid to flow unobstructed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner protrusion is pressed radially inward to form a sealing area, then sealing performance is improved, but the inner protrusion bulges into the fluid channel causing backwaters

Engineering Contradiction:
Improvesealing performanceVSAvoidbackwaters in fluid flow
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The inner periphery of the inner protrusion is designed with a specific shape that causes it to reduce in inner diameter toward the axial direction. This localized geometric feature ensures that while the inner protrusion is pressed radially inward for sealing, it maintains a streamlined profile that prevents fluid flow disruption and backwater formation.

Inventive Principle:
Principle #3Local quality

2Reliability

If the inner protrusion is deformed to seal against the inner sleeve, then sealing area is formed, but fluid channel cross-section is reduced causing flow obstruction

Engineering Contradiction:
Improvesealing area formationVSAvoidfluid flow efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The inner periphery of the inner protrusion features a specific geometric configuration that reduces inner diameter toward the axial direction. This localized design allows the protrusion to deform radially inward for sealing while maintaining an streamlined shape that prevents flow obstruction and maintains fluid channel efficiency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4151894B1Resinous pipe joint
Publication Date: 2024.11.06 NIPPON PILLAR PACKING CO LTD
  • EP4151894B1 patent drawingFigure 1
  • EP4151894B1 patent drawingFigure 2
  • EP4151894B1 patent drawingFigure 3

AI summary

A resin tube fitting 1 prevents backwaters between its body and inner ring. The fitting includes a body 5, an inner ring 6, and a union nut 7. The body has main, outer, and inner sleeves (11, 12, 13), and a groove 14. The inner ring has a cylinder 31, an insert 32, and outer and inner protrusions (33, 34). The union nut has a body 51 and a pressing member 53. The inner sleeve has a through hole serving as a channel. The inner protrusion extends from the cylinder to an axial direction to contact the inner sleeve. The inner protrusion has a through hole serving as another channel connected with the inner sleeve's channel. The tip 45 of the inner protrusion 34 has an inner diameter not less than the minimum inner diameter of the inner sleeve. An inner peripheral surface 71 is located at the inner periphery of the inner protrusion 34 and causes it to reduce in inner diameter toward another axial direction.