Pig Trap Injector Nozzle Layout for High-Force Pig Launching

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Solution Overview

Problem

Existing pig launchers in pipeline systems are inefficient in applying force for launching pigs due to low velocity fluid jets perpendicular to the barrel, which results in insufficient momentum and dynamic pressure, often requiring mechanical assistance and being costly to implement and maintain.

Innovation Solution

A directed jet impulse pig launch system using a pig trap fluid injector assembly with nozzles oriented at an oblique angle to deliver high-velocity fluid jets directly to the backside of pigs, eliminating the need for mechanical assistance and allowing for sequential launching of multiple pigs without additional hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If fluid enters the barrel as a fluid jet perpendicular to the wall of the barrel, then the fluid flow can be introduced into the barrel, but the momentum of the jet crosses from one side of the barrel to the other, diminishing most of the momentum and dropping its dynamic pressure without doing any immediate work

Engineering Contradiction:
Improvefluid jet velocityVSAvoidlaunch force on pig
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The patent applies local quality by directing the fluid jet to a specific localized area - the backside of the pig - rather than allowing it to cross the entire barrel. The nozzle is positioned and angled to concentrate the fluid impact precisely where it is needed to propel the pig forward, maximizing the effectiveness of the fluid momentum at the point of application.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the dimension of fluid application by introducing the jet at an oblique angle rather than perpendicular to the barrel wall. This angular introduction allows the fluid to travel along the barrel axis and impact the pig from behind, utilizing the longitudinal dimension of the barrel to deliver momentum directly to the pig in the direction of motion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the kicker line is made large in diameter to match the mainline, then fluid can be diverted into the barrel, but the fluid flow velocity remains relatively low (typically about one-third the diameter of the mainline), creating insufficient stagnation pressure and force to move the pig

Engineering Contradiction:
Improvefluid flow rateVSAvoidfluid jet velocity
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent applies parameter changes by modifying the nozzle geometry and orientation to transform the fluid flow parameters. The nozzle is designed with specific dimensions and an oblique angle that convert the available fluid flow into a high-velocity directed jet, changing the velocity parameter while maintaining adequate flow quantity to generate sufficient launch force.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If mechanical means such as hydraulically activated pins are employed to prevent multiple pigs from launching at once, then pig control is achieved, but the cost to contain and control pigs increases significantly due to hydraulic cylinders, weldment sites, power units, and control systems

Engineering Contradiction:
Improvepig launch controlVSAvoidhydraulic control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing a system where the fluid dynamics themselves provide the control mechanism. The directed jet impulse naturally propels pigs in sequence based on their positioning in the barrel, eliminating the need for external hydraulic control systems. The system uses the fluid flow's own energy and momentum to achieve both launch and sequential control functions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the control function from the launch mechanism itself. Rather than adding separate hydraulic cylinders and control systems to manage pig launching, the invention removes these mechanical control elements and relies on the inherent sequential nature of fluid impulse delivery to naturally control which pig launches when, based on pig positioning and fluid flow timing.

Inventive Principle:
Principle #2Taking out (Extraction)

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 achieves launch forces 10 to 15 times greater than conventional launchers, ensuring reliable and efficient pig movement into the pipeline system with reduced hardware and maintenance costs, and can be retrofitted into existing launchers for bi-directional capabilities.

Implementation Method 1

the nozzle is oriented to deliver a jet of fluid in a downstream direction

Methodology Applied
Scientific EffectJet: Jet

Implementation Method 2

discharging a part of the diverted portion through the nozzle toward a back side of a vertical element of the pig, the discharged part impinging on the back side of the vertical element

Methodology Applied
Scientific EffectImpulse force: Impact Force

Implementation Method 3

the leak path allows the annular space to fill with fluid and pressurise around the outside annular surface of the nozzle assembly

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP3615858B1Pig trap fluid injector assembly and method
Publication Date: 2023.08.23 TDW DELAWARE INC
  • EP3615858B1 patent drawingFigure 1
  • EP3615858B1 patent drawingFigure 2
  • EP3615858B1 patent drawingFigure 3~6

AI summary

A pig trap (10) of this disclosure may include one or more injectors or nozzles (81) located along a sidewall (12) of the barrel (1 1) and oriented to deliver a jet of fluid toward a back side (75) of a vertical member (71) of a pig or tool. The nozzle (81) may be part of an assembly that includes a longitudinally extending pipe (87) having a flat-profile flange (89) at an inlet end (99), a curved-profile flange (91) at the nozzle end, and a bend (105) in between the two ends. When the assembly is installed in a sidewall opening of a pig trap, the nozzle (81) delivers a jet of fluid toward the back side (75) of a vertical member (71) of the pig. A leak path (1 1 1) may be provided through flanges or formed between the sidewall opening and a periphery of the curved-profile flange (91). Launch forces of more than 10 to 15 times that of a conventional launcher may be achieved.