Resin Pipe Joint Inner Ring Shape for Smooth Flow Sealing

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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 resin tube fitting 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 fluid flow by maintaining a constant cross-sectional area, and the insert has slope and inner peripheral surfaces that deform under pressure to prevent bulging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

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

Engineering Contradiction:
Improvesealing performanceVSAvoidbackwaters and fluid stagnation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The inner protrusion is designed with a tapered inner peripheral surface that has different geometric properties at different locations. The tapering shape (smaller inner diameter toward the axial direction) creates a specific local geometry that prevents bulging into the fluid channel while still allowing the outer protrusion to press the inner sleeve for sealing. This local geometric differentiation resolves the contradiction between achieving sealing pressure and preventing fluid flow obstruction.

Inventive Principle:
Principle #3Local quality

2Reliability

If the inner protrusion is pressed radially inward to form sealing area, then the radial sealing is improved, but the inner protrusion deforms and blocks fluid flow

Engineering Contradiction:
Improveradial sealingVSAvoidfluid flow efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The inner protrusion features a tapered inner peripheral surface that creates different functional zones: the tapered portion prevents bulging into the fluid channel to maintain flow efficiency, while the outer surface can still be pressed radially inward by the outer protrusion to achieve proper sealing. This local geometric differentiation allows simultaneous achievement of radial sealing and unobstructed fluid flow.

Inventive Principle:
Principle #3Local quality

3Reliability

If the fitting is tightly coupled to prevent leakage, then the sealing reliability is improved, but fluid components precipitate and solidify into particles

Engineering Contradiction:
Improvesealing reliabilityVSAvoidparticle formation from precipitation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The tapered inner peripheral surface of the inner protrusion creates a specific local flow geometry that eliminates dead zones and backwaters where fluid stagnation occurs. The smooth tapered surface guides fluid flow continuously through the fitting, preventing stagnation that would otherwise cause precipitation and particle formation, while still maintaining tight sealing through the pressing mechanism.

Inventive Principle:
Principle #3Local quality

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

This design prevents backwaters and ensures smooth fluid flow by eliminating obstructions within the fluid channel, reducing the risk of fluid stagnation and precipitation, and improving the precision of fluid flow through the inner ring.

Implementation Method 1

The first inner peripheral surface is located at the inner periphery of the inner protrusion and causes the inner protrusion to reduce in inner diameter toward the first axial direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The pressing member is designed to press the insert of the inner ring with the tube in between when the second thread is engaged with the first thread

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 3

the outer protrusion presses the inner sleeve radially inward

Methodology Applied
Scientific EffectRadial compression: Compression

Implementation Method 4

the inner sleeve presses the inner protrusion radially inward

Methodology Applied
Scientific EffectRadial compression: Compression

Data Source

PatentEP3604883B1Resinous pipe joint
Publication Date: 2022.12.28 NIPPON PILLAR PACKING CO LTD
  • EP3604883B1 patent drawingFigure 1
  • EP3604883B1 patent drawingFigure 2
  • EP3604883B1 patent drawingFigure 3

AI summary

A resin tube fitting prevents backwaters between its body and inner ring. The fitting includes a body, an inner ring, and a union nut. The body has main, outer, and inner sleeves, and a groove. The inner ring has a cylinder, an insert, and outer and inner protrusions. The union nut has a body and a pressing member. 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 of the inner protrusion has an inner diameter not less than the minimum inner diameter of the inner sleeve. An inner peripheral surface is located at the inner periphery of the inner protrusion and causes it to reduce in inner diameter toward another axial direction.