Fiberglass Pipe Jointing via Injected Curing Compound

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Solution Overview

Problem

Current reinforced thermosetting resin (RTR) pipe jointing systems face limitations in withstanding high pressures required for oil field applications, particularly in terms of pressure rating and diameter, due to inadequate joint performance.

Innovation Solution

A mechanical-injected joint system for fiberglass pipes, involving a push-fit design with a spigot and socket configuration, where a joining compound is injected into a cavity between the two pipes to form a secure bond, allowing for increased pressure and diameter capabilities without the need for heavy machinery or complex assembly processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If traditional RTR pipe jointing systems are used, then installation is simple, but pressure rating and diameter capabilities are limited

Engineering Contradiction:
Improvepressure ratingVSAvoidjointing system complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The jointing system is divided into distinct functional components: a spigot portion with an outer surface, a socket portion with an inner surface, and a separate joining compound. This segmentation allows each component to be optimized independently - the spigot and socket provide structural alignment while the injected compound provides pressure-bearing bonding, enabling high pressure ratings without increasing overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A joining compound is introduced as an intermediary material between the spigot and socket portions. This compound is injected into the cavity formed by the push-fit connection and cures to create a strong bond. The intermediary compound enables the joint to withstand high pressures and larger diameters by distributing stress uniformly across the bonding interface, rather than relying solely on mechanical friction or compression

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If complex assembly processes or heavy machinery are used, then pressure and diameter capabilities increase, but installation time and costs increase

Engineering Contradiction:
Improvejoint strengthVSAvoidinstallation time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The spigot and socket portions are designed with predetermined geometric features (tapered surfaces, sealing ridges, alignment guides) that enable self-alignment and automatic cavity formation during insertion. This preliminary design of the joint geometry eliminates the need for on-site machining, alignment equipment, or complex assembly procedures, allowing workers to simply push-fit the components together before injecting the joining compound

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The traditional mechanical jointing methods (welding, threading, flanging) that require heavy machinery and skilled operators are replaced with a chemical-bonding system. The joining compound provides the bonding function through chemical adhesion and curing, substituting complex mechanical fastening systems with a simpler injection-and-cure process that can be performed with basic injection equipment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If simple push-fit design is used, then installation is fast, but pressure rating is insufficient

Engineering Contradiction:
Improveinstallation speedVSAvoidjoint reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The joining compound undergoes a parameter change from liquid to solid state through curing. It is injected in liquid form to fill the cavity completely and ensure all surfaces are coated, then cures to a solid state to provide high-strength bonding. This parameter change allows the joint to maintain the simplicity and speed of push-fit installation while achieving the reliability and pressure rating of a fully bonded connection

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The joint system combines multiple materials with complementary properties: the spigot and socket portions provide structural integrity and geometric precision, the joining compound provides adhesive bonding and stress distribution, and the cured compound creates a rigid bond. This composite approach integrates the advantages of mechanical fit (alignment and initial strength) with chemical bonding (uniform stress distribution and high pressure resistance), achieving both installation speed and joint reliability

Inventive Principle:
Principle #40Composite materials

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 system enables fiberglass pipes to achieve higher pressure ratings and larger diameters, reducing installation time and costs while maintaining a secure and leak-tight seal, thus overcoming the limitations of existing RTR pipe jointing systems.

Implementation Method 1

injecting a joining compound into the cavity

Methodology Applied
Scientific EffectInjection: Injector

Implementation Method 2

the joining compound is injected into the cavity and allowed to cure

Methodology Applied
Scientific EffectCuring: Phase Change

Data Source

PatentEP2786057B1Fiberglass pipe jointing methods and systems
Publication Date: 2020.11.04 FUTURE PIPE IND GRP
  • EP2786057B1 patent drawingFigure 1A~1B
  • EP2786057B1 patent drawingFigure 2A~2C
  • EP2786057B1 patent drawingFigure 3A~3B

AI summary

A system of jointing reinforced thermosetting resin (RTR) pipe, including: a first RTR pipe with a spigot portion, the spigot portion having a first joining surface; a second RTR pipe with a socket portion shaped to receive the spigot portion, the socket portion having a second joining surface; and a cavity between the first joining surface and the second joining surface, the cavity formed when the spigot portion is push-fit into the socket portion; and an injectable/curable material located in the cavity. Additionally, a method of jointing RTR pipe, including the steps of: push-fitting a spigot portion of a first pipe into a socket portion of a second pipe, forming a cavity between the spigot portion and the socket portion; injecting a joining compound into the cavity; and curing the joining compound.